Organic compounds and organic light-emitting devices

Abstract

The present invention provides an organic compound that can be suitably used as a light-emitting material for displays, and an organic light-emitting device containing such an organic compound. [Solution] An organic compound according to one embodiment of the present invention has a lone pair of electrons and a π electron orbital, and the energy level E of the lowest singlet excited state S1 S1 From the lowest triplet excited state T1, the energy level E T1 The energy difference ΔE after subtracting ST -0.20eV≦ΔE ST It is <0.0090 eV.

Description

[Technical Field]

[0001] The present invention relates to organic compounds that can be used as light-emitting materials, and to organic light-emitting devices containing such organic compounds. [Background technology]

[0002] Organic light-emitting diodes (OLEDs) are an example of organic light-emitting devices that utilize organic electroluminescent (hereinafter referred to as OLEDs) materials composed of organic compounds. Even now, with displays and lighting devices equipped with OLEDs available on the market, there is a high demand for novel OLED materials with higher luminous efficiency. OLED materials are an example of light-emitting materials. OLED materials include fluorescent materials and phosphorescent materials. The theoretical internal quantum efficiency of phosphorescent materials is four times higher than that of fluorescent materials. Therefore, research and development of phosphorescent materials has been leading from the perspective of increasing internal quantum efficiency. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2015 / 159971 [Non-patent literature]

[0004] [Non-Patent Document 1] Hiroki Uoyama et al. "Highly efficient organic light-emitting diodes from delayed fluorescence", Nature, 2012, 492, 234. [Non-Patent Document 2] Johannes Ehrmaier et. al.,"Singlet-Triplet Inversion in Heptazine and in Polymeric Carbon Nitrides", The Journal of Physical Chemistry A, 123, 8099-8108 (2019) [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, phosphorescent materials have the problem of being expensive because they contain costly metals such as iridium.

[0006] [Regarding Patent Document 1 and Non-Patent Document 1] As a light-emitting material that is less expensive than phosphorescent materials containing expensive metals such as iridium, thermally activated delayed fluorescence materials described in Patent Document 1 and Non-Patent Document 1 are known. Hereinafter, thermally activated delayed fluorescence materials will be referred to as TADF (Thermally Activated Delayed Fluorescence) materials.

[0007] TADF materials have the lowest singlet excited state S1 energy level E S1 From the lowest triplet excited state T1, the energy level E T1 The energy difference ΔE after subtracting ST The material is configured to have a low voltage (for example, around 100 meV). TADF materials utilize the lowest triplet excited state T1, which would normally be deactivated by heat, as delayed fluorescence by thermally inducing a reverse intersystem crossing from the lowest triplet excited state T1 to the lowest singlet excited state S1. As a result, it is theoretically possible to increase the internal quantum efficiency of organic EL materials to 100%.

[0008] Also, ΔE ST By reducing the energy to approximately the same level as room temperature energy, we successfully promoted reverse intersystem crossing and shortened the emission lifetime of delayed fluorescence to a few microseconds. This emission lifetime is comparable to that of conventional phosphorescent materials.

[0009] However, when assuming the use of TADF materials in displays, it has to be said that the emission lifetime of TADF materials is far from the practical level. The emission lifetime of TADF materials is about three orders of magnitude longer compared with the typical emission lifetime of organic EL materials used in displays provided in the market.

[0010] This long emission lifetime causes the degradation of TADF materials due to the increase in the triplet exciton density in TADF materials and the decrease in the emission efficiency during high-brightness emission.

[0011] [Regarding Non-Patent Document 2] Due to the exchange interaction in the excited state, the energy level E T1 of the lowest triplet excited state T1 is lower than the energy level E S1 of the lowest singlet excited state. In other words, ΔE ST becomes positive.

[0012] On the other hand, organic compounds with a negative ΔE ST obtained by calculation have been reported (for example, see Non-Patent Document 2). The organic compound described in Non-Patent Document 2 has ΔE ST < -0.23 eV (see Table 3 of Non-Patent Document 2). Thus, a negative ΔE ST with a large absolute value belongs to a region called the Marcus inverted region. In organic EL materials belonging to the Marcus inverted region, it is considered that the rate constant of reverse intersystem crossing from the lowest triplet excited state T1 to the lowest singlet excited state S1 becomes small. In addition, the inventors of the present application have confirmed that such organic EL materials exhibit extremely low emission intensity and emission quantum yield experimentally. Therefore, it is not practical to use organic EL materials belonging to the region called the Marcus inverted region as light-emitting materials for displays.

[0013] One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to provide an organic compound that can be suitably used as a light-emitting material for displays, and an organic light-emitting device including such an organic compound.

Means for Solving the Problem

[0014] In order to solve the above problems, the organic compound according to the first aspect of the present invention is an organic compound having a lone pair and a π electron orbital, and the energy level E of the lowest singlet excited state S1 minus the energy level E of the lowest triplet excited state T1 The energy difference ΔE ST is -0.20 eV ≤ ΔE ST < 0.0090 eV.

[0015] In addition, the organic compound according to the second aspect of the present invention has a radiative deactivation rate constant k r in addition to the configuration of the organic compound according to the first aspect described above, and 6 s -1 < k r is adopted.

[0016] In addition, the organic compound according to the third aspect of the present invention has a configuration in which the oscillator strength f is 0.0050 < f in addition to the configuration of the organic compound according to the first or second aspect described above.

[0017] In addition, the organic compound according to the fourth aspect of the present invention is a heptazine derivative represented by the following formula (1) and having three arbitrary substituents R1, R2, and R3 independently of each other, in addition to the configuration of the organic compound according to any one of the first to third aspects described above.

Chemical formula

[0018] In addition, the organic compound according to the fifth aspect of the present invention has a configuration in which the substituents R1, R2, and R3 are composed of two types of substituents, in addition to the configuration of the organic compound according to the fourth aspect described above.

[0019] Furthermore, the organic compound according to the sixth aspect of the present invention employs a configuration in which, in addition to the configuration of the organic compound according to the fourth aspect described above, the substituents R1, R2, and R3 are each composed of three different substituents.

[0020] Furthermore, the organic compound according to the seventh aspect of the present invention employs a configuration in which, in addition to the configuration of the organic compound according to the fourth aspect described above, the substituents R1, R2, and R3 are composed of only one type of substituent.

[0021] To solve the above problems, the organic compound according to the eighth aspect of the present invention is an organic compound having a lone pair of electrons and a π electron orbital, represented by the following formula (1), and is a heptadine derivative having three arbitrary substituents R1, R2, and R3 independently of each other, wherein the substituents R1, R2, and R3 are composed of two or three types of substituents. [ka]

[0022] Furthermore, the organic light-emitting device according to the ninth aspect of the present invention comprises an organic compound according to any one of the first to eighth aspects of the present invention.

[0023] Furthermore, the organic light-emitting device according to the tenth aspect of the present invention employs a configuration that, in addition to the configuration of the organic light-emitting device according to the ninth aspect described above, includes a light-emitting layer comprising the organic compound that functions as a dopant compound and a host compound.

[0024] To solve the above problems, an organic light-emitting device according to an eleventh aspect of the present invention comprises a light-emitting layer containing a dopant compound and a host compound. In this organic light-emitting device, the host compound is an organic compound having a lone pair of electrons and a π electron orbital, and the energy level E of the lowest singlet excited state S1 S1 From the lowest triplet excited state T1, the energy level E T1 The energy difference ΔE after subtracting ST If negative or 0 eV ≤ ΔE STIt is an organic compound with an eV of <0.0090 eV.

[0025] To solve the above problems, an organic light-emitting device according to a twelfth aspect of the present invention comprises a light-emitting layer containing a dopant compound and a host compound. In this organic light-emitting device, the host compound is a heptazine derivative having a lone pair of electrons and a π electron orbital, represented by the following formula (1), and having an arbitrary substituent R1. [ka] [Effects of the Invention]

[0026] According to one aspect of the present invention, it is possible to provide an organic compound that can be suitably used as a light-emitting material for displays, and an organic light-emitting device containing such an organic compound. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram of energy levels in an organic compound according to one embodiment of the present invention. [Figure 2] This graph shows the emission spectrum, temperature dependence of transient emission decay, and temperature dependence of rate constant kDF of a mixed thin film of organic compound A and PPF, which is a first embodiment of the present invention. [Figure 3] This graph shows the emission spectrum, temperature dependence of transient emission decay, and temperature dependence of rate constant kDF of a toluene solution of organic compound A, which is a first reference example of the present invention. [Figure 4] This graph shows the correlation between the energy difference ΔEST and oscillator intensity f in organic compounds 1 to 38, which are the second reference example group of the present invention. [Figure 5] This is a scatter plot showing the phase relationship between the energy difference ΔEST and oscillator intensity f in the organic compound pX-Y, ​​which is a third example of the present invention. [Figure 6]This table shows the energy difference ΔEST and oscillator strength f of organic compounds pX-Y numbered 1 to 200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 7] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 201 to 400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 8] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 401 to 600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 9] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 601 to 800, in ascending order of their energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 10] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 801 to 1000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 11] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 1001 to 1200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 12] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 1201 to 1400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 13] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 1401 to 1600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 14]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 1601 to 1800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 15] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 1801 to 2000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 16] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 2001 to 2200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 17] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 2201 to 2400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 18] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 2401 to 2600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 19] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 2601 to 2800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 20] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 2801 to 3000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 21] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 3001 to 3200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 22]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 3201 to 3400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 23] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 3401 to 3600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 24] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 3601 to 3800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 25] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 3801 to 4000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 26] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 4001 to 4200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 27] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 4201 to 4400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 28] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 4401 to 4600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 29] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 4601 to 4800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 30]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 4801 to 5000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 31] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 5001 to 5200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 32] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 5201 to 5400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 33] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 5401 to 5600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 34] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 5601 to 5800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 35] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 5801 to 6000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 36] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 6001 to 6200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 37] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 6201 to 6400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 38]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 6401 to 6600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 39] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 6601 to 6800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 40] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 6801 to 7000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 41] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 7001 to 7200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 42] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 7201 to 7400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 43] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 7401 to 7600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 44] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 7601 to 7800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 45] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 7801 to 8000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 46]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 8001 to 8200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 47] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 8201 to 8400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 48] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 8401 to 8600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 49] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 8601 to 8800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 50] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 8801 to 9000, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 51] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 9001 to 9200, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 52] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 9201 to 9400, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 53] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 9401 to 9600, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 54]This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 9601 to 9800, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 55] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 9801 to 10000, in ascending order of energy difference ΔEST, from organic compound pX-Y to organic compound pX-Y numbered 9801 to 10000. [Figure 56] This table shows the energy difference ΔEST and oscillator intensity f for organic compounds pX-Y numbered 10001 to 10006, in ascending order of energy difference ΔEST, from the third example group of organic compounds pX-Y according to the present invention. [Figure 57] This graph shows the emission spectrum of a toluene solution of organic compound C, which is one embodiment of the present invention. [Figure 58] This graph shows the temperature dependence of the transient luminescence decay of a toluene solution of organic compound C, which is one embodiment of the present invention. [Figure 59] This graph shows the temperature dependence of the rate constant kDF of delayed fluorescence of a toluene solution of organic compound C, which is one embodiment of the present invention. [Figure 60] This graph shows the emission spectrum of a toluene solution of organic compound D, which is one embodiment of the present invention. [Figure 61] This graph shows the temperature dependence of the transient luminescence decay of a toluene solution of organic compound D, which is one embodiment of the present invention. [Figure 62] This graph shows the temperature dependence of the rate constant kDF of delayed fluorescence of a toluene solution of organic compound D, which is one embodiment of the present invention. [Figure 63] This graph shows the emission spectrum of a toluene solution of organic compound E, which is one embodiment of the present invention. [Figure 64] This graph shows the transient luminescence decay of a toluene solution of organic compound E, which is one embodiment of the present invention. [Figure 65] This graph shows the emission spectrum of an organic light-emitting device using organic compound C, which is one embodiment of the present invention. [Figure 66] This graph shows the current density-voltage-luminance characteristics of an organic light-emitting device using organic compound C, which is one embodiment of the present invention. [Figure 67] This graph shows the external quantum efficiency-luminance characteristics of an organic light-emitting device using organic compound C, which is one embodiment of the present invention. [Figure 68] This graph shows the transient emission decay of an organic light-emitting device using organic compound C, which is one embodiment of the present invention, and an organic light-emitting device using 4CzIPN. [Modes for carrying out the invention]

[0028] [Organic compounds] <Overview> An organic compound according to one aspect of the present invention is an organic compound having lone pairs of electrons and π electron orbitals. Hereinafter, an organic compound according to one aspect of the present invention will be referred to as the organic compound of the present invention. The organic compound of the present invention can exist in at least a ground state S0, a lowest singlet excited state S1, and a lowest triplet excited state T1 (see Figure 1). When electrons and holes are induced in the organic compound of the present invention, some of them are excited to the lowest singlet excited state S1, and most of the remaining ones are excited to the lowest triplet excited state T1. Hereinafter, induced electrons and holes will be collectively referred to as carriers.

[0029] The organic compound of the present invention is the lowest singlet excited state S1 energy level E S1 From the lowest triplet excited state T1, the energy level E T1 The energy difference ΔE after subtracting ST -0.20eV≦ΔE ST It is configured to be <0.0090 eV. Note that in Figure 1, the energy level E T1 is energy level E S1 A state exceeding that, i.e., an energy difference ΔE ST This indicates a state where the value is positive.

[0030] Furthermore, in the organic compound of the present invention, the energy difference ΔE STis preferably negative, that is, -0.20 eV ≦ ΔE ST is preferably configured to be < 0 eV.

[0031] In addition, in the organic compound of the present invention, the radiative deactivation rate constant k r is 1.0×10 6 s -1 < k r is preferably.

[0032] In addition, in the organic compound of the present invention, the oscillator strength f is preferably 0.0050 < f.

[0033] Note that each of the above-described energy difference ΔE ST , radiative deactivation rate constant k r , and oscillator strength f is described with two significant figures. When each of the energy difference ΔE ST , radiative deactivation rate constant k r , and oscillator strength f has three or more significant figures, the significant figures are made two by rounding the third significant figure.

[0034] <Advantages of the organic compound> The lowest triplet excited state T1 is an unstable excited state. Therefore, for example, when the organic compound of the present invention is used as a light-emitting material for a display including an organic light-emitting diode, the longer the time the excited carriers stay in the lowest triplet excited state T1, the more likely the organic compound is to deteriorate, and the more likely the driving life, which is the life that can be driven as a light-emitting material, is to be shortened.

[0035] In the organic compound of the present invention, since the energy difference ΔE ST is less than 0.0090 eV, it is more likely to undergo reverse intersystem crossing from the lowest triplet excited state T1 to the lowest singlet excited state S1 compared to the TADF materials described in Patent Document 1 and Non-Patent Document 1. That is, the reverse intersystem crossing rate constant k RISC of the organic compound of the present invention is the rate constant k RISCIt is larger than that. In other words, the organic compounds of the present invention can shorten the time that excited carriers remain in the lowest triplet excited state T1 compared to the TADF materials described in Patent Document 1 and Non-Patent Document 1.

[0036] Furthermore, the emission lifetime of fluorescence emission resulting from the recombination of carriers in the lowest singlet excited state S1 is shorter than the emission lifetime of fluorescence emission resulting from the recombination of carriers from the lowest triplet excited state T1. Therefore, the organic compounds of the present invention can achieve a shorter emission lifetime than the TADF materials described in Patent Document 1 and Non-Patent Document 1.

[0037] The organic compound of the present invention, configured as described above, can have higher durability than the TADF materials described in Patent Document 1 and Non-Patent Document 1, and consequently, the operating life of organic light-emitting diodes and displays using the organic compound of the present invention can be extended.

[0038] Furthermore, in the organic compound of the present invention, the energy difference ΔE ST Since the rate constant k is -0.20 eV or higher, compared to the organic compounds described in Non-Patent Document 2, RISC This allows for a larger size, as well as increased luminescence intensity and luminescence quantum yield.

[0039] Energy difference ΔE ST Organic compounds whose energy difference ΔE is clearly below -0.20 eV are considered to have an energy difference of ΔE ST Since k is negative and its absolute value is too large, it belongs to the Marcus inversion region. Organic compounds belonging to the Marcus inversion region have a rate constant k RISC The calculation results predict that this value will be small. Furthermore, it has been experimentally confirmed that organic compounds belonging to the Marcus inversion region have very low luminescence intensity and luminescence quantum yield. Therefore, it is not practical to use organic compounds belonging to the Marcus inversion region as luminescent materials for displays.

[0040] Therefore, the organic compounds of the present invention can be suitably used as light-emitting materials for displays equipped with organic light-emitting diodes, compared to the TADF materials described in Patent Document 1 and Non-Patent Document 1 and the organic compounds described in Non-Patent Document 2. Note that an organic light-emitting diode is one embodiment of an organic light-emitting device, and an organic light-emitting diode containing the organic compounds of the present invention falls within the scope of the present invention.

[0041] <Energy difference ΔE ST Upper and lower limits > (Energy difference ΔE) ST (Preferred lower limit) Inverse intersystem crossing in organic compounds, the weak spin-orbit interaction (H) of the organic compound SO Assuming a non-adiabatic transition based on ), its rate constant k RISC This can be expressed by equation (1), which is a Marcus theory-type equation (see Aizawa, N., Harabuchi, Y., Maeda, S., & Pu, Y.-J. Kinetic Prediction of Reverse Intersystem Crossing in Organic Donor-Acceptor Molecules. ChemRxiv. Preprint. https: / / doi.org / 10.26434 / chemrxiv.12203240.v1).

number

[0042] Here

number

number

[0043] From equations (1) and (2), the velocity constant k RISC ΔE ST The maximum occurs when +λ=0. The theoretical value of λ calculated by TDDFT is 0.050eV to 0.20eV for typical TADF materials (see Aizawa et al. above), and 0.0030eV to 0.10eV for heptadine derivatives, which are an example of the organic compounds of the present invention. The organic compounds of the present invention have an energy difference ΔE ST The lower limit of the rate constant k is -0.20 eV. RISC It can be made larger.

[0044] Furthermore, in an organic compound according to one aspect of the present invention, the energy difference ΔE ST It may be below -0.20 eV.

[0045] (Energy difference ΔE) ST (Upper limit) The rearrangement energy λ is always positive because it is based on the most stable energy of the lowest triplet excited state T1. To date, the smallest ΔE in an isolated, single organic molecule has been found. ST A value of 0.009 eV has been reported (see Hironori Kaji et al. "Purely organic electroluminescent material realizing 100% conversion from electricity to light", Nat. Commun. 6, 8476 (2015)). Intermolecular exchange interactions are due to an energy difference ΔE ST It is one of the origins of [something]. Note that intermolecular exchange interactions are smaller than intramolecular exchange interactions. The organic compounds of the present invention have an energy difference ΔE ST The upper limit of is 0.0090 eV, which means that the rate constant k RISC This can be made larger than the TADF material described in Patent Document 1 and Non-Patent Document 1.

[0046] <Lower limit value of the radiation inactivation rate constant k r > In the organic compound of the present invention, the radiation inactivation rate constant k r is 1.0×10 6 s -1 <k r ≦1×10 9 s -1 is preferable. According to this configuration, compared with typical light-emitting materials used in displays equipped with organic light-emitting diodes available on the market, quantum yields and emission lifetimes close to theirs, or quantum yields and emission lifetimes of the same degree, can be realized.

[0047] Also, in the organic compound of the present invention, it is preferable that the oscillator strength f satisfies 0.0050 < f. According to this configuration, the fluorescence intensity can be increased. Therefore, when the organic compound of the present invention is used as a light-emitting material constituting the light-emitting layer of an organic light-emitting diode, the luminance of the organic EL device can be increased.

[0048] <Regarding the wavelength of fluorescence>

[0049] The wavelength λ (nm) of the fluorescence emitted by the organic compound of the present invention is determined according to the energy difference ΔE S1 from the energy level E of the lowest singlet excited state S1 S0 to the energy level E of the ground state S0 S01 (eV). The wavelength λ is obtained by λ = 1240 / ΔE S01 .

[0050] In the organic compound of the present invention, the wavelength λ is not particularly limited.

[0051] <Preferred examples of the organic compound> Hereinafter, a preferred example of the organic compound of the present invention will be described more specifically. However, the organic compound of the present invention has an energy difference ΔE ST that is negative or 0 eV ≦ ΔE STAs long as the relationship <0.0090eV is satisfied, the chemical structure is not limited to those exemplified below. Furthermore, the organic compounds of the present invention are -0.20eV≦ΔE ST It is preferable to satisfy the relationship <0.0090eV.

[0052] In a preferred example, the organic compound of the present invention has a structure represented by the following formula (2). [ka]

[0053] In formula (2), R1, R2, and R3 (hereinafter sometimes referred to as R1-R3) are arbitrary substituents, independent of each other. X1, X2, X3, X4, X5, and X6 (hereinafter sometimes referred to as X1-X6) are either nitrogen atoms or CH, independent of each other. When X1-X6 are nitrogen atoms, a preferred example is a heptadine derivative.

[0054] In the above formula (2), it is preferable that at least one of X1 to X6 is a nitrogen atom, more preferably two or more or three or more are nitrogen atoms, and even more preferably that all are nitrogen atoms. When all of X1 to X6 are nitrogen atoms, the structure is as shown in the following formula (1). [ka]

[0055] In equation (1), the definitions of R1 to R3 are the same as in equation (2).

[0056] Below, we will provide a more detailed explanation of a preferred example of R1 to R3 in equations (1) and (2).

[0057] R1 to R3 may each have different substituents, but a structure in which two of R1 to R3 (for example, R2 and R3, or R1 and R3) are the same substituent and the other one is a different substituent is preferred. In other words, it may be preferable for R1 to R3 to be composed of three different substituents, two different substituents, or one different substituent.

[0058] In particular, the symmetry in a preferred example is D 3h By making it lower, the energy difference ΔE ST Since it is negative, that is, -0.20eV ≤ ΔE ST In some cases, it is possible to realize organic compounds that satisfy the <0eV relationship and have a high luminescence quantum yield.

[0059] (Examples of R1-R3) Examples of each of R1 to R3 are as follows: [ka] [ka] [ka] [ka]

[0060] (Regarding an example of R1) In a more preferable example, R1 takes the structure shown in equation (3). -S-R31, -O-R31, or -N-(R32)R33···(3) In formula (3), R31 to R33 are independently linear or cyclic hydrocarbon groups having 20 or fewer carbon atoms, and may be substituted with substituents. In one example, it is preferable that the linear or cyclic hydrocarbon groups have 10 or fewer carbon atoms. Furthermore, R32 and R33, which are bonded to the same nitrogen (N), may be bonded to each other to form a ring structure.

[0061] Examples of linear or cyclic hydrocarbon groups as R31 to R33 include, specifically, linear alkyl groups, linear alkenyl groups, linear alkynyl groups, or hydrocarbon ring groups.

[0062] Examples of linear alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, hexyl, and octyl groups, which have 20 or fewer carbon atoms, preferably 15 or fewer, more preferably 10 or fewer, and even more preferably 5 or fewer, in a linear or branched configuration.

[0063] Examples of linear alkenyl groups include vinyl groups, propenyl groups, butenyl groups, 2-methyl-1-propenyl groups, hexenyl groups, octenyl groups, etc., which are linear or branched and have 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10 or fewer.

[0064] Examples of linear alkynyl groups include ethynyl group, propynyl group, butynyl group, 2-methyl-1-propynyl group, hexynyl group, octinyl group, etc., which are linear or branched and have 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10 or fewer.

[0065] Examples of hydrocarbon ring groups include cycloalkyl groups such as cyclopropyl, cyclohexyl, and tetradecahydroanthranyl groups, which have 3 or more carbon atoms, preferably 5 or more, and 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10; cycloalkenyl groups such as cyclohexenyl groups, which have 3 or more carbon atoms, preferably 5 or more, and 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10; and aryl groups such as phenyl, anthranyl, phenanthuryl, and ferrocenyl groups, which have 6 or more carbon atoms and 18 or fewer, preferably 10 or fewer carbon atoms.

[0066] The linear alkyl groups, linear alkenyl groups, linear alkynyl groups, or hydrocarbon ring groups exemplified as R31 to R33 may have substituents. Examples of substituents on a linear alkyl group, a linear alkenyl group, or a linear alkynyl group include halogen groups (halogen atoms) such as fluorine, chlorine, bromine, and iodine atoms.

[0067] Examples of substituents on hydrocarbon ring groups include, in addition to the halogen groups mentioned above, amino groups (-NH2), nitro groups (-NO2), cyano groups (-CN), hydroxyl groups (-OH), alkyl groups, alkyl halides, and alkoxy groups. Examples of alkoxy groups include methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups, butoxy groups, isobutoxy groups, sec-butoxy groups, tert-butoxy groups, pentyloxy groups, hexyloxy groups, and octyloxy groups. The alkyl portion of alkyl groups, alkyl halides, and alkoxy groups preferably has 5 or fewer carbon atoms.

[0068] A more specific example of the structure shown in equation (3) above is as follows: [ka]

[0069] (Regarding an example of R2) In a more preferred example, R2 is selected from a hydrocarbon ring group or a heterocyclic group.

[0070] Examples of hydrocarbon ring groups include cycloalkyl groups such as cyclopropyl, cyclohexyl, and tetradecahydroanthranyl groups, which have 3 or more carbon atoms, preferably 5 or more, and 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10; cycloalkenyl groups such as cyclohexenyl groups, which have 3 or more carbon atoms, preferably 5 or more, and 20 or fewer carbon atoms, preferably 15 or fewer, and more preferably 10; and aryl groups such as phenyl, anthranyl, phenanthuryl, and ferrocenyl groups, which have 6 or more carbon atoms and 18 or fewer, preferably 10 or fewer carbon atoms.

[0071] Examples of heterocyclic groups include heteroaryl groups consisting of a monocyclic ring with 5 to 6 members or a fused ring formed by the fusion of 2 to 6 monocyclic rings with 5 to 6 members, and heterocycloalkyl groups consisting of a monocyclic ring with 5 to 6 members or a fused ring formed by the fusion of 2 to 6 monocyclic rings with 5 to 6 members. Examples of heteroatoms include nitrogen, oxygen, and sulfur atoms. Specifically, examples include monocyclic rings with 5 members such as the thienyl group; monocyclic rings with 6 members such as the pyridyl group, 1-piperidinyl group, 2-piperidinyl group, and 2-piperazinyl group; and fused rings formed by the fusion of 2 to 6 monocyclic rings with 5 to 6 members such as the benzothienyl group, carbazolyl group, quinolinyl group, and octahydroquinolinyl group.

[0072] A preferred example of R2 is a phenyl group which may have 1 to 5 substituents, or a pyridyl group which may have 1 to 4 substituents, as described later. If substituents are present, the number is not particularly limited, but 1 to 3 substituents may be preferred.

[0073] These hydrocarbon ring groups or heterocyclic groups may have substituents as described above. Examples of substituents include halogen groups (halogen atoms) such as fluorine, chlorine, bromine, and iodine atoms; amino groups (-NH2); nitro groups (-NO2); cyano groups (-CN); hydroxyl groups (-OH); linear or branched alkyl groups with 20 or fewer carbon atoms, preferably 15 or fewer, more preferably 10 or fewer, and even more preferably 5 or fewer carbon atoms, such as methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, hexyl groups, and octyl groups; alkyl halides; alkoxy groups; and the like. Examples of alkoxy groups include methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups, butoxy groups, isobutoxy groups, sec-butoxy groups, tert-butoxy groups, pentyloxy groups, hexyloxy groups, and octyloxy groups. The alkyl portion of alkyl groups, alkyl halides, and alkoxy groups preferably has 5 or fewer carbon atoms.

[0074] The following describes in more detail a preferred example of R2, which may have 1 to 5 substituents, a phenyl group, or a pyridyl group, which may have 1 to 4 substituents. The substituents on the phenyl group or pyridyl group are preferably the halogen group, hydroxyl group, alkyl group, alkyl halide, or alkoxy group mentioned above. In a phenyl group which may have 1 to 5 substituents, the preferred number of substituents is 0, 1, 2, or 3. When there is 1 substituent, it is preferable that the substituent is located at the 2nd or 4th position of the phenyl group. When there are 2 substituents, it is preferable that the substituent is located at the 2nd, 4th or 2nd, 6th positions of the phenyl group. When there are 3 substituents, it is preferable that the substituent is located at the 2nd, 4th, and 6th positions of the phenyl group. When there are 2 or 3 substituents, it may be preferable that 2 or 3 substituents are selected from the group consisting of alkyl groups, alkoxy groups, and halogen groups. In a pyridyl group which may have 1 to 4 substituents, the preferred number of substituents is 0, 1, 2, or 3, and 0, 1, or 2 may be more preferred.

[0075] A more specific example of R2 is as follows: [ka]

[0076] (Regarding an example of R3) In a more preferred example, R3 is selected from the substituents exemplified as R1 or R2. R1 to R3 may be different substituents, but it is more preferable that R3 and R1 are the same substituent, or that R3 and R2 are the same substituent.

[0077] (An example of a preferred combination of R1, R2, and R3) In one example of a preferred combination of R1, R2, and R3, R1 is a substituent that satisfies formula (3) above, and R2 and R3 are phenyl groups which may be substituted with 1 to 3 substituents. Here, R2 and R3 are more preferably the same group. Even more preferably, R1 is one of the following: [ka] Furthermore, R2 and R3 are combinations selected from unsubstituted phenyl groups and phenyl groups substituted with 1 to 3 methyl groups (preferably R2 and R3 are the same group).

[0078] Particularly preferred examples of the organic compounds of the present invention include the following. [ka] [ka] [ka]

[0079] Among the above, the organic compounds numbered 1st, 2nd, 3rd, 4th (11th), 6th, 16th, 23rd, 25th, 27th, and 29th (33rd) may be more preferable.

[0080] <An example of a synthesis method for an organic compound represented by formula (1) or formula (2)> The method for synthesizing organic compounds is not particularly limited. For example, a compound in which R1 to R3 in formula (1) or formula (2) are halogen groups (precursor compound) can be synthesized by reacting it with compounds corresponding to R1, R2, and R3 in the presence of a Lewis acid catalyst (e.g., aluminum chloride). When using two or more compounds corresponding to R1, R2, and R3, different R1, R2, and R3 can be introduced by appropriately adjusting the amounts of these compounds used, the timing of their addition to the reaction system, and other reaction conditions. Details of the synthesis method can also be found in the Examples section described later.

[0081] <Uses of the organic compound of the present invention> The organic compounds of the present invention are suitably used, for example, as light-emitting materials for the light-emitting layer of organic light-emitting devices or organic light-emitting devices. The organic compounds of the present invention may form a light-emitting layer on their own, or they may form a light-emitting layer as a composition (sometimes referred to as a "light-emitting composition") obtained by mixing them with other compounds. Organic light-emitting devices or organic light-emitting devices that contain the organic compounds of the present invention in their light-emitting layer are also within the scope of the present invention.

[0082] The light-emitting layer often contains a host compound and a dopant compound. The dopant compound is sometimes called a guest compound. The host compound is responsible for charge (electron and hole) transport. The dopant compound is responsible for light emission. The organic compounds of the present invention may be used as either a host compound or a dopant compound in the light-emitting layer. In particular, among the organic compounds of the present invention, the energy difference ΔE ST -0.20eV≦ΔE STCompounds that satisfy the relationship <0.0090eV can be used as either a host compound or a dopant compound. Furthermore, among the organic compounds of the present invention, the energy difference ΔE ST is ΔE ST Compounds that satisfy the relationship <-0.20eV are preferably used as host compounds.

[0083] Furthermore, the method used to fabricate the light-emitting layer is not limited. For example, a vacuum deposition method or a coating method may be used to fabricate the light-emitting layer. Examples of coating methods include inkjet printing, gravure printing, and nozzle coating. In addition, the substrate constituting the organic light-emitting device may be any translucent substrate, and may be a hard substrate such as glass or a flexible substrate such as resin. [Examples]

[0084] [First Example] The first embodiment of the present invention, organic compound A, is described below. Organic compound A is a heptadine derivative represented by the following formula (4). That is, organic compound A has heptadine as its core, and the three substituents R1, R2, and R3 are such that R1 is a 1-piperidinyl group (i.e., -N-(R32)R33 as shown in formula (4), with -R32 and -R33 bonded to each other to form a ring structure), and R2 and R3 are both 4-methoxyphenyl groups. In other words, the three substituents are composed of two types of substituents. [ka]

[0085] <Energy difference ΔE ST And calculation of oscillator strength f > (TDDFT calculation) Using TDDFT calculations, we optimized the structure of the lowest singlet excited state S1 and the lowest triplet excited state T1 of organic compound A, and determined the energy difference ΔE of organic compound A. STAnd the oscillator strength f were calculated respectively. For the TDDFT calculation, the TDDFT calculation implemented in Gaussian16 was used, the ωB97X-D was used for the functional, and the 6-31G(d) was used for the basis function.

[0086] (ADC(2) calculation) In the most stable structure of the lowest triplet excited state T1 of organic compound A obtained by the above TDDFT calculation, the energy difference ΔE of organic compound A was calculated using the ADC(2) calculation ST And the oscillator strength f were calculated respectively. For the ADC(2) calculation, the ADC(2) calculation implemented in Q-Chem5.2 was used, and the 6-31G(d) was used for the basis function.

[0087] The energy difference ΔE of organic compound A calculated by the TDDFT calculation and the ADC(2) calculation ST And the oscillator strength f are shown in Table 1. The energy difference ΔE of organic compound A calculated using the ADC(2) calculation that can also consider two-electron excitation ST And the oscillator strength f were, respectively, ΔE ST =-0.35 eV, and f = 0.017. That is, organic compound A was predicted to show a negative energy difference ΔE ST And a relatively large oscillator strength f.

Table 1

[0088] <Synthesis scheme> Organic compound A was obtained by the following synthesis scheme: Under an argon atmosphere, AlCl3 (1.83 mmol) was added at 0°C to a 5 ml solution of Anisole (2.5 mmol) in dichloromethane. After standing at that temperature for 40 minutes, trichloroheptadine (0.83 mmol) was added at 0°C. After 10 minutes, the temperature was raised to room temperature and the mixture was run overnight. After 20 hours, reflux was started and continued for 4 hours. After the temperature returned to room temperature, 0.5 ml (excess amount) of piperidine was added. After 1 hour, water was added to quench the mixture. Organic compound A, a yellowish-white substance, was isolated by column purification (1% AcOEt / DCM → 15% AcOEt / DCM). In this example, the yield of organic compound A was 15%. [ka]

[0089] <Luminous properties> For a mixed thin film of the organic compound A synthesized in this manner and 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF), (1) the emission spectrum was measured using a HORIBA Fluoromax-4 fluorescence spectrophotometer, (2) the emission quantum yield was measured using a Hamamatsu Photonics C9920 integrating sphere, and (3) the emission lifetime τ of the delayed fluorescence was measured using a HORIBA Fluorolog-3. In this example, the concentration of organic compound A in the mixed thin film was 5 wt%. The upper, middle, and lower panels of Figure 2 show, respectively, the emission spectrum, the temperature dependence of transient emission decay, and the rate constant k of the delayed fluorescence of the mixed thin film in this example. DF This graph shows the temperature dependence of [the function / phenomenon].

[0090] The measurements described in (1), (2), and (3) above were performed under an inert nitrogen atmosphere. Furthermore, the measurement described in (3) above was performed using a UNISOKU CoolSpeK cryostat, with the temperature varied. The temperature dependence of the obtained luminescence lifetime τ was analyzed using equation (3), which assumes thermal equilibrium between the lowest singlet excited state S1 and the lowest triplet excited state T1, and the energy difference ΔE STand the radiative deactivation rate constant k r The experimental values of were estimated. In Equation (3), k B is the Boltzmann constant, T is the absolute temperature, and k DF is the rate constant of delayed fluorescence.

Number

[0091] The mixed thin film of this example showed blue emission (CIE 0.16, 0.14) with a maximum emission wavelength of 442 nm (see the upper part of Figure 2). Further, the mixed thin film of this example had a high emission quantum yield of 85%, a short emission lifetime τ of 1066 ns, and a radiative deactivation rate constant k r 1.2×10 8 s -1 was shown. From the temperature dependence of the emission lifetime τ, the energy difference ΔE ST was estimated to be ΔE ST =0.004 eV (see the middle and lower parts of Figure 2). Further, the oscillator strength f estimated using Equation (4) from the radiative deactivation rate constant k r taking into account the degeneracy was f = 0.35.

Number

Number

[0092] 〔First Reference Example〕 A toluene solution of the organic compound A synthesized using the synthesis scheme described in the first example is taken as the first reference example. In the toluene solution of this reference example, the concentration of the organic compound A is 8×10 -5M is the value. For the toluene solution in this reference example, as in the first example, (1) the emission spectrum was measured using a HORIBA Fluoromax-4 fluorescence spectrophotometer, (2) the emission quantum yield was measured using a Hamamatsu Photonics C9920 integrating sphere, and (3) the emission lifetime τ of the delayed fluorescence was measured using a HORIBA Fluorolog-3. The upper, middle, and lower panels of Figure 3 show, respectively, the emission spectrum of the toluene solution in this reference example, the temperature dependence of the transient emission decay, and the rate constant k of the delayed fluorescence. DF This graph shows the temperature dependence of [the function / phenomenon].

[0093] The toluene solution in this reference example exhibited blue emission (CIE 0.16, 0.16) with a maximum emission wavelength of 442 nm (see upper panel of Figure 3). Furthermore, the toluene solution in this reference example showed a high emission quantum yield of 75% and a short emission lifetime τ of 588 ns. From the temperature dependence of the emission lifetime τ, the energy difference ΔE ST ΔE ST = Estimated to be 0.033 eV, and the radiative deactivation rate constant k r to k r = 2.2 × 10 7 s -1 This was the estimated cost (see the middle and lower sections of Figure 3).

[0094] [Second group of examples] The second group of examples of the present invention, organic compounds 1 to 38, are described below. Each of organic compounds 1 to 38 is one of the 38 organic compounds mentioned above, each being a particularly preferred example of the organic compounds of the present invention.

[0095] Similar to the first example, the lowest singlet excited state S1 and lowest triplet excited state T1 of organic compounds 1-38 were optimized using TDDFT calculations, and the energy difference ΔE of organic compounds 1-38 was determined. ST The oscillator strength f was calculated for each of these. Figure 4 shows the energy difference ΔE for organic compounds 1 to 38. ST This graph shows the correlation between and oscillator intensity f. The solid line in Figure 4 represents f. (ΔEST) =(ΔE ST The function f expressed as (-0.18) × 0.3 (ΔEST)This represents that each of the organic compounds 1 to 38 has f ≥ (ΔE ST The relationship (-0.18) × 0.3 is satisfied.

[0096] Energy difference ΔE of organic compound A, which is the first example. ST When using TDDFT calculations, ΔE ST =0.27eV, but when calculated from the luminescence properties of the synthesized organic compound A, ΔE ST = 0.0040 eV. That is, the energy difference ΔE calculated from the luminescence characteristics. ST This is the energy difference ΔE when using TDDFT calculations. ST It was found that the value shifts in the direction of becoming smaller compared to [the previous value].

[0097] Based on the results of the first embodiment described above, the energy difference ΔE ST In the space spanned by the oscillator strength f, the energy difference ΔE was obtained using TDDFT calculations. ST And the oscillator strength f is f≧(ΔE ST Each of the organic compounds 1 to 38 that satisfy the relationship (-0.18) × 0.3 is included within the scope of the present invention.

[0098] [Comparative Example 1] The organic compound B described in Non-Patent Document 2 is explained below. Organic compound B is a heptadine derivative represented by the following formula (5). That is, organic compound B has heptadine as its core, and the three substituents R1, R2, and R3 are all 4-methoxyphenyl groups. [ka]

[0099] For organic compound B, the energy difference ΔE was calculated using ADC(2) calculations. ST And the oscillator strength f is ΔE, respectively. ST The values ​​were -0.250eV and f = 0.0000050.

[0100] On the other hand, a toluene solution of organic compound B was prepared, and, as in the first example, (1) the emission spectrum was measured using a HORIBA Fluoromax-4 fluorescence spectrophotometer, (2) the emission quantum yield was measured using a Hamamatsu Photonics C9920 integrating sphere, and (3) the emission lifetime τ was measured using a HORIBA Fluorolog-3. As a result, the radiative deactivation rate constant k r , and each of the oscillator strength f are, respectively, k r = 1.0 × 10 6 s -1 , and f = 0.0039. Furthermore, it was found that organic compound B does not exhibit delayed fluorescence. Therefore, with respect to organic compound B, the energy difference ΔE ST We were unable to evaluate it.

[0101] As described above, organic compound B does not exhibit delayed fluorescence, and the energy difference ΔE ST Because it cannot be evaluated, it is not included in the scope of the present invention. Organic compound B has low fluorescence intensity due to its extremely low oscillator intensity. Therefore, organic compound B is difficult to use as a light-emitting material for displays.

[0102] [Third group of examples] The third example of the present invention, the organic compound pX-Y, ​​is described below.

[0103] <Nomenclature rules for organic compounds> In the organic compound pX-Y, ​​X and Y are each integers between 1 and 186, corresponding to the numbers of the 186 substituents exemplified in the section (Examples of R1-R3). In the structure of formula (1) below, the organic compound pX-Y employs substituents specified by the common X as R2 and R3, and substituents specified by Y as R1. [ka]

[0104] For example, the organic compound p37-151 is represented by the following formula (6). [ka]

[0105] <Screening Calculation> In organic compounds pX-Y, ​​R2 and R3 are selected from 186 substituents, and similarly, R1 is selected from 186 substituents. Therefore, organic compounds pX-Y are a group of 34,596 organic compounds in total.

[0106] For these 34,596 organic compound pX-Y groups, T1 structure optimization was performed using Unrestricted DFT implemented in Gaussian16. The functional used was LC-BLYP, and the domain decomposition parameter was 0.18 Bohr. -1 The basis set used was 6-31G. Using the obtained T1 optimized structure, the energy difference ΔE was calculated by TDDFT. ST The oscillator intensity f was calculated. The functional used was LC-BLYP, and the domain division parameter was 0.18 Bohr. -1 The basis set used was 6-31G(d). Hereafter, this calculation will be referred to as the screening calculation.

[0107] The results of the screening calculations for 34596 organic compounds pX-Y are shown in Figure 5. Figure 5 shows the energy difference ΔE for 34596 organic compounds pX-Y. ST And a scatter plot showing the phases of oscillator intensity f. Also, among 34596 organic compounds pX-Y, ​​the energy difference ΔE ST Figures 6 to 56 show the 10006 organic compounds pX-Y selected in ascending order of ΔE. ST And a table showing the oscillator intensity f. Note that the numbers shown in Figures 6 to 56 represent the energy difference ΔE. ST They are numbered in ascending order.

[0108] <High precision calculation> Furthermore, for organic compounds C, D, and E among the organic compounds pX-Y, ​​the T1 structure was optimized using Unrestricted MP2 implemented in Gaussian16. The basis set used was cc-pVDZ. Using the obtained T1 optimized structures, the energy difference ΔE was calculated using EOM-CCSD or ADC(2). ST The oscillator intensity f was also calculated. The basis set used was cc-pVDZ. Hereafter, this calculation will be referred to as the high-precision calculation.

[0109] Organic compounds C and D show a relatively small energy difference ΔE in the screening calculations described above. ST It exhibited a large oscillator intensity f. Furthermore, organic compound E is an analog of organic compounds C and D.

[0110] Organic compound C is organic compound p37-151, represented by the following formula (7). [ka] The synthesis of organic compound C was carried out as follows: Intermediate I1, shown in formula (8) below, was dissolved in m-xylene, and aluminum chloride (1.0 g, 7.6 mmol) was added at 0°C. The mixture was stirred at 0°C for 2 hours and at room temperature for 17 hours, after which water was added. Subsequently, chloroform was added and the mixture was stirred for 30 minutes. The organic layer was then separated, dried over sodium sulfate, and concentrated. Columnar purification (CHCl3 100%) was performed to obtain organic compound C. The amount of organic compound C obtained as a yellow solid was 17 mg (0.224 mmol, 7.1%). 1H NMR (600 MHz, CDCl3) δ[ppm] = 2.39 (s, 6H), 2.73 (s, 6H), 4.88 (q, J = 8.2 Hz, 2H), 7.11 - 7.13 (m, 4H), 8.19 (d, J = 7.8 Hz, 2H) MS (MALDI-TOF): 478.60 [calcd:479.17] [ka]

[0111] The synthesis of intermediate I1 was carried out as follows: 2,2,2-trifluoroethanol (199 mL, 2.78 mmol) was dissolved in tetrahydrofuran (10 mL), and sodium hydride (121 mg, 3.0 mmol) was added at 0°C. After stirring for 30 minutes, ciameric acid (700 mg, 2.53 mmol) was slowly added dropwise to a tetrahydrofuran solution (20 mL) at 0°C, and the mixture was stirred at 0°C for 2 hours, followed by 1 hour at room temperature. Intermediate I1 was obtained by concentrating the reaction mixture under reduced pressure.

[0112] Organic compound D is organic compound p37-107, represented by the following formula (9). [ka] The synthesis of organic compound D was carried out as follows: Intermediate I2, shown in formula (10) below, was dissolved in m-xylene (20 mL), and aluminum chloride (980 mg, 0.79 mmol) was added under an argon atmosphere at room temperature, and the mixture was stirred for 17 hours. Water was added to stop the reaction. After extraction with chloroform, the organic layer was dried over sodium sulfate and concentrated. Purification was performed by column chromatography (AcOEt: CHCl3 = 0:100 - 5:95) to obtain the target product. The obtained yellow solid organic compound D amounted to 25 mg (0.054 mmol, 2.2%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.66 - 1.71 (m, 6H), 2.36 (s, 6H), 2.67 (s, 6H), 3.96 (br s, 4H), 7.06 - 7.07 (m, 4H), 7.99 (d, J = 8.4 Hz, 2H) MS (MALDI-TOF): 465.71 [calcd:464.24] [ka]

[0113] The synthesis of intermediate I2 was carried out as follows. Cyanuric chloride (677 mg, 2.45 mmol) was dissolved in tetrahydrofuran (20 mL), and piperidine (266 mL, 2.7 mmol) was added at room temperature. After 30 minutes, the temperature was raised to 50 °C and stirred for 45 minutes. After returning to room temperature, the reaction solution was concentrated under reduced pressure to obtain intermediate I2.

[0114] Organic compound E is organic compound p37-37 and is represented by the following formula (11). [Chemical formula] The synthesis of organic compound E was carried out as follows. Cyanuric acid (623 mg, 2.26 mmol) was dissolved in m-xylene (20 mL), and diphenylamine (420 mg, 2.49 mmol) was added at room temperature. After stirring for 2.5 hours, the temperature was raised to 50 °C and stirred for another 2 hours. After cooling to 0 °C, aluminum chloride (904 mg, 6.8 mmol) was added, and after stirring at room temperature for 17 hours, water was added. Subsequently, chloroform was added after 30 minutes, the organic layer was separated, dried over sodium sulfate, concentrated, and column purified (CHCl3 100%) to obtain the target product. The obtained white solid organic compound p37-37 was 70 mg (0.14 mmol, 6.4%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 2.34 (s, 6H), 2.63 (s, 6H), 7.03 (br s, 4H), 7.28 - 7.31 (m, 6H), 7.38 (t, J = 7.8 Hz, 4H), 7.97 (d, J = 8.4 Hz, 2H) MS (MALDI-TOF): 549.94 [calcd:548.24]

[0115] The high-precision calculation results of organic compounds C, D, and E are shown in Table 2. [Table 2]

[0116] <Evaluation of Luminescence Characteristics> The luminescence spectra of a toluene solution of organic compound C (concentration 8.0 × 10 -5 M) and a mixed thin film (concentration 10 wt%) with 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) prepared by vacuum evaporation were measured using a Fluoromax-4 fluorescence spectrophotometer manufactured by HORIBA. The luminescence quantum yields of the toluene solution and the mixed thin film of organic compound C were measured using an integrating sphere C9920 manufactured by Hamamatsu Photonics. The luminescence lifetime τ of the toluene solution and the mixed thin film of organic compound C was measured using a Fluorolog-3 fluorescence lifetime measurement device manufactured by HORIBA. The luminescence lifetime τ can also be said to be the delayed fluorescence lifetime. The above measurements were carried out with an excitation light wavelength of 370 nm under an inert nitrogen atmosphere. Also, the measurement of the delayed fluorescence lifetime τ was carried out by changing the temperature using a cryostat CoolSpeK manufactured by UNISOKU. The temperature dependence of the obtained delayed fluorescence lifetime τ was analyzed by Equation (3) assuming the thermal equilibrium between S1 and T1, and the experimental values of the energy difference ΔE ST and the radiative deactivation rate constant k r were estimated.

Equation

[0117] Similar to organic compound C, toluene solutions of organic compounds D, E, F, G, H, I, J, K, L, M were prepared and their luminescence characteristics were evaluated.

[0118] Organic compound F is organic compound p1-151 and is represented by the following formula (12).

Chemical formula

[0119] Organic compound G is organic compound p7-151, represented by the following formula (13). [ka] The synthesis of organic compound G was carried out as follows: Intermediate I1 was dissolved in toluene (10 mL), aluminum chloride (872 mg, 6.5 mmol) was added at 0°C, and the mixture was stirred at 0°C for 30 minutes, followed by 19 hours at room temperature. Chloroform was added to water, and the mixture was stirred for 30 minutes, after which the organic layer was separated. After drying over sodium sulfate, the mixture was concentrated and purified by column (CHCl3 100%) to obtain the target product. The resulting yellow solid organic compound G amounted to 90 mg (0.20 mmol, 9.2%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 2.46 (s, 6H), 4.90 (q, J = 8 Hz, 2H), 7.33 (d, J = 7.8 Hz, 4H), 8.45 (d, J = 8.4 Hz, 4H) MS (MALDI-TOF): 452.64 [calcd:451.14]

[0120] Organic compound H is organic compound p7-107, represented by the following formula (14). [ka] The synthesis of organic compound H was carried out as follows: 100 mg, 0.36 mmol of ciameryl chloride was dissolved in toluene (3 mL), and piperidine (36 mL, 0.36 mmol) was added at room temperature. After 5 minutes, the temperature was raised to 100°C and stirred for 30 minutes, then returned to room temperature. Aluminum chloride (106 mg, 0.79 mmol) was added, and the mixture was stirred at 100°C for 1 hour, then returned to room temperature, and water was added. The organic layer was separated, dried over sodium sulfate, concentrated, and purified by column (AcOEt: CHCl3 = 0:100 - 1:20) to obtain the target product. The amount of organic compound H obtained as a yellow solid was 19 mg (0.044 mmol, 12.1%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.68 - 1.72 (m, 6H), 2.44 (s, 6H), 3.99 (br s, 4H), 7.29 (d, J = 7.8 Hz, 4H), 8.44 (d, J = 7.8 Hz, 4H)

[0121] Organic compound I is organic compound p64-166, represented by the following formula (15). [ka] The synthesis of organic compound I was carried out as follows: To a solution of intermediate I3 (608 μL, 4.3 mmol) shown in formula (16) below in dichloromethane (11.8 mL), aluminum chloride (616 mg, 4.6 mmol) was added at room temperature and the mixture was stirred for 40 minutes. A solution of compound 2 in dichloromethane (12 mL) was slowly added and the mixture was stirred at room temperature for 20.5 hours. A 1 M aqueous sodium hydroxide solution (16 mL) was added at 0°C and the mixture was stirred at room temperature for 4 hours, after which it was filtered using Celite. After adding a 20% aqueous sodium chloride solution to the reaction mixture, the organic layer was separated, dried over anhydrous sodium sulfate, concentrated, and purified by column (CH2Cl2- CH2Cl2: MeOH = 9 : 1) to obtain the crude product (117 mg). The crude product was purified by preparative column (SunFire, Hexane / siRNA = 82 : 18), and organic compound I was obtained as the first peak. The amount of the obtained yellow solid organic compound I was 8.4 mg (0.015 mmol, 1.4%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 0.80-0.92 (br, 2H), 1.20-1.38 (br, 2H), 1.38-1.50 (br, 2H), 1.69-1.79 (br, 2H), 2.01-2.11 (br, 2H), 2.41 (s, 12H), 3.80 (s, 6H), 3.87-3.96 (br, 1H), 6.60 (s, 4H) [ka]

[0122] The synthesis of intermediate I3 was carried out as follows: Diisopropylethylamine (93 μL, 0.54 mmol) and cyclohexanethiol (66 μl, 0.54 mmol) were added to a suspension of ciameryl chloride-potassium trichloride mixture (536 mg, 1.1 mmol) in toluene (8.9 mL) at room temperature, and the mixture was heated under reflux for 14 hours. After cooling to room temperature and filtering out the insoluble matter, intermediate I3 was obtained by concentration under reduced pressure.

[0123] Organic compound J is organic compound p107-4 and is represented by the following formula (17). [Chemical formula] The synthesis of organic compound J was carried out as follows. Cyameluric acid chloride (70 mg, 0.25 mmol) was added to a dichloromethane (3 mL) solution of aluminum chloride (133 mg, 1.0 mmol) and methoxybenzene (41 μL, 0.38 mmol) at 0 °C. After 10 minutes, the reaction solution was warmed to room temperature and stirred for 17 hours. An excess amount of piperidine (0.5 mL) was added and stirred for 30 minutes, and then diluted with water and chloroform. The separated organic layer was concentrated and then purified by column (CH2Cl2 100% - AcOEt:CH2Cl2 = 1:4) to obtain the target product. The obtained yellow solid organic compound J was 6.8 mg (0.015 mmol, 6.1%). 1 H NMR (600 MHz, CDCl3) δ [ppm] = 1.64 - 1.69 (m, 12H), 3.91 (t, 4H), 3.95 (t, 4H), 6.93 (d, J = 9 Hz, 2H), 8.48 (d, J = 8.4 Hz, 2H) 13 C NMR (600 MHz, CDCl3) δ [ppm] = 24.44, 26.16, 45.50, 55.44, 113.47, 127.71, 132.10, 155.21, 156.09, 161.40, 163.88, 172.87 MS (FD-TOF): 445.2342 [M] + , calcd. for C 23 H 27 N9O (445.2339)

[0124] Organic compound K is organic compound p107-107 and is represented by the following formula (18). [Chemical formula] The synthesis of organic compound K was carried out as follows: To a solution of aluminum chloride (133 mg, 1.0 mmol) and methoxybenzene (41 μL, 0.38 mmol) in dichloromethane (3 mL), ciameryl chloride (70 mg, 0.25 mmol) was added at 0 °C. After 10 minutes, the reaction solution was raised to room temperature and stirred for 17 hours. An excess amount of piperidine (0.5 mL) was added and stirred for 30 minutes, after which it was diluted with water and chloroform. The separated organic layer was concentrated and purified by column chromatography (CH2Cl2 100% - AcOEt:CH2Cl2=1:4) to obtain the target product. The obtained white solid organic compound K amounted to 30 mg (0.071 mmol, 28.4%). 1 H NMR (600 MHz, CDCl3) δ [ppm] = 1.59 - 1.65 (m, 18H), 3.87 (t, 12H) 13 C NMR (600 MHz, CDCl3) δ[ppm] = 24.50, 26.12, 45.15, 155.11, 161.59 MS (FD-TOF): 422.2658 [M] + , calcd. for C 21 H 30 N 10 (422.2655)

[0125] Organic compound L is organic compound p105-105, represented by the following formula (19). [ka] The synthesis of organic compound L was carried out as follows: Dicyclohexylamine (1.39 ml, 7.0 mmol) was added to a suspension of ciameryl chloride-potassium trichloride mixture (501 mg, 1.0 mmol) in toluene (5.5 mL) at room temperature. The mixture was stirred at 100°C for 21 hours using a heat block. After adding dichloromethane and water to the reaction mixture, the organic layer was separated, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the crude product (1.088 g). Recrystallization and column purification (CH2Cl2) were performed from the crude dichloromethane to obtain organic compound L. The obtained white solid organic compound L amounted to 220.7 mg (0.310 mmol, 31.0%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.10-1.22 (br, 12H), 1.27-1.44 (br, 18H), 1.58-1.74 (br, 18H), 1.80 (d, J = 12.0 Hz, 12H), 2.08-2.94 (br, 6H) MS (MALDI-TOF): 712.251 [M+H = 712.067]

[0126] Organic compound M is organic compound p144-144, represented by the following formula (20). [ka] The synthesis of organic compound M was carried out as follows: 138 mg, 0.5 mmol of ciameryl chloride and 220 mg, 1.8 mmol of dimethylaminopyridine were placed in a flask, and 3 mL of cyclohexanol was added under a nitrogen atmosphere at room temperature. After 5 minutes, the temperature was raised to 60°C, and then to 70°C after 1 hour, and the mixture was stirred for 17 hours. After returning to room temperature and adding water, the mixture was extracted with chloroform, and the organic layer was dried over sodium sulfate and concentrated. Purification by column chromatography (CHCl3 100%) was performed to obtain the target product. The obtained white solid organic compound M amounted to 41 mg (0.088 mmol, 18%). 1H NMR (600 MHz, CDCl3) δ[ppm] = 1.28 - 1.34 (m, 3H), 1.36 - 1.43 (m, 6H), 1.53 - 1.56 (m, 3H), 1.58 - 1.64 (m, 6H), 1.77 - 1.79 (m, 6H), 1.95 - 1.98 (m, 6H), 5.15 - 5.19 (m, 3H), MS (ESI): 468.27 [calcd:467.26]

[0127] (Luminescence properties of organic compound C) Organic compound C exhibited blue emission with a maximum emission wavelength of 449 nm in toluene solution (see Figure 57). The emission quantum yield of organic compound C in toluene solution was high at 74%, and it showed a short emission lifetime τ of 214 ns. From the temperature dependence of the emission lifetime τ, the energy difference ΔE was determined. ST At -6 meV, the radiative deactivation rate constant k r 1.1 × 10 7 s -1 This was the estimated amount (see Figures 58 and 59).

[0128] (Luminescence properties of organic compound D) Organic compound D exhibited blue emission with a maximum emission wavelength of 442 nm in toluene solution (see Figure 60). The emission quantum yield of organic compound D in toluene solution was high at 67%, and it showed a short emission lifetime τ of 565 ns. From the temperature dependence of the emission lifetime τ, the energy difference ΔE was determined. ST With a voltage of 47 meV and a radiative deactivation rate constant k r 3.2 × 10 7 s -1 This was the estimated cost (see Figures 61 and 62).

[0129] (Luminescence properties of organic compound E) Organic compound E exhibited green emission with a maximum emission wavelength of 518 nm in toluene solution (see Figure 63). The emission quantum yield of organic compound E in toluene solution was 12%. No delayed fluorescence was observed from transient emission decay measurements; only fluorescence with an emission lifetime τ of 90 ns was observed (see Figure 64).

[0130] (Luminescence properties of organic compounds F-M) Table 3 shows the luminescence properties of organic compounds F, G, H, I, J, K, L, and M. Table 3 also includes the luminescence properties of organic compounds C, D, and E mentioned above.

[0131] As shown in Table 3, in toluene solution, organic compounds F and G exhibit a negative energy difference ΔE, similar to organic compound C. ST This was shown. Organic compound H, like organic compound D, has a positive energy difference ΔE. ST This was observed. Organic compounds I, J, K, L, and M did not show delayed fluorescence, similar to organic compound E. [Table 3]

[0132] <Evaluation of Organic Light-Emitting Devices> A glass substrate coated with 130 nm thick indium tin oxide (ITO) was ultrasonically cleaned in the following order: neutral detergent, ultrapure water, acetone, and 2-propanol. After boiling in 2-propanol, it was treated with UV ozone for 30 minutes. On this ITO-coated glass substrate, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) diluted to 60% with ultrapure water (Clevious, manufactured by Hereaeus) was applied. TMA dispersion of CH8000 was spin-coated under air, and then dried at 200°C for 10 minutes to deposit a 30 nm thick PEDOT:PSS film. Subsequently, an organic light-emitting device was fabricated by vacuum deposition using the following layers: a 5 nm thick layer of molybdenum trioxide (MoO3), a 3 nm thick layer of 4,4′′-bis(triphenylsilanyl)-(1,1′,4′,1′′)-terphenyl (BST), a 10 nm thick layer of bis(4-(dibenzo[b,d]furan-4-yl)phenyl)diphenylsilane (DBFSiDBF), a 15 nm thick mixed film of 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) and organic compound C (10 wt%), a 10 nm thick layer of PPF, a 40 nm thick layer of tris(8-hydroxyquinolinato)aluminium (Alq3), a 1 nm thick layer of (8-hydroxyquinolinato)lithium (Liq), and a 100 nm thick layer of aluminum. The light-emitting area of ​​the organic light-emitting device was 2.0 × 2.0 mm². 2 The structural formulas for PEDOT, PSS, BST, DBFSiDBF, PPF, Alq3, and Liq are as follows. [ka]

[0133] Similarly, we fabricated an organic light-emitting device using 2,4,5,6-tetra(carbazol-9-yl)isophthalonitrile (4CzIPN) instead of organic compound C.

[0134] The current density-voltage-luminance characteristics of the fabricated organic light-emitting device were measured using a Tektronix Keithley 2400 source meter and a Konica Minolta CS-200 luminance meter. The EL spectrum was measured using a Hamamatsu Photonics PMA-11 multi-channel spectrometer. Transient emission attenuation was measured using a Hamamatsu Photonics H7826 photosensor, an Agilent 33220A function generator, and a Tektronix DPO3052 oscilloscope, by applying a pulsed voltage (maximum 8 V, minimum -4 V) at a frequency of 1 kHz.

[0135] The organic light-emitting device using organic compound C exhibited blue light emission from organic compound C at currents from 0.1 mA to 5.0 mA (see Figure 65). Furthermore, this organic light-emitting device showed excellent current density-voltage-luminance characteristics with no leakage current (see Figure 66). In this organic light-emitting device, the maximum external quantum efficiency of organic compound C reached 17% (see Figure 67). These results indicate that organic compound C can convert triplet excitons into singlet excitons and can be used as an organic light-emitting device. Moreover, compared to the common TADF material 4CzIPN, organic compound C in this organic light-emitting device showed rapid transient emission decay (see Figure 68). This is due to the negative energy difference ΔE of organic compound C. ST This is because it allows for the rapid conversion of triplet excitons into singlet excitons, which can then be used as light emission.

[0136] <Other Organic Compounds> In addition to the organic compounds C-M mentioned above, we also synthesized organic compounds p4-107, p4-4, p37-118, p139-139, p141-141, p142-142, p140-140, p162-162, and p65-166.

[0137] The organic compound p4-107 is represented by the following formula (21). [ka] The synthesis of organic compound p4-107 was carried out as follows: 70 mg, 0.3 mmol of ciameryl chloride was dissolved in 3 mL of dichloromethane, and aluminum chloride (130 mg, 1.0 mmol) and methoxybenzene (80 mL, 0.8 mmol) were added at 0°C. After stirring for 15 minutes, the temperature was raised to room temperature and stirred for 18 hours. An excess amount of piperidine (1.0 mL) was added to the reaction mixture, and after 30 minutes, water and dichloromethane were added to dilute it. The organic layer was separated, dried over sodium sulfate, concentrated, and purified by column (AcOEt:CH2Cl2=1:50 - 1:6) to obtain organic compound p4-107. The obtained yellow solid organic compound p4-107 amounted to 5.4 mg (0.012 mmol, 4.6%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.68 - 1.72 (m, 6H), 2.44 (s, 6H), 3.99 (br s, 4H), 7.29 (d, J = 7.8 Hz, 4H), 8.44 (d, J = 7.8 Hz, 4H) MS (MALDI-TOF): 469.61 [calcd:468.20]

[0138] The organic compound p4-4 is represented by the following formula (22). [ka] The synthesis of the organic compound p4-4 was carried out as follows: 100 mg, 0.36 mmol of ciameryl chloride was dissolved in 3 mL of dichloromethane, and 196 mL, 1.8 mmol of methoxybenzene and 173 mg, 1.3 mmol of aluminum chloride were added at 0°C. After 5 minutes, the temperature was raised to room temperature and the mixture was stirred for 24 hours. After adding water, the organic layer was separated and dried over sodium sulfate. After concentration, the mixture was purified by column chromatography (AcOEt: CHCl3 = 0:100 - 1:20) to obtain the target product. The amount of the obtained yellow solid organic compound p4-4 was 34.5 mg (0.071 mmol, 19.8%). 1H NMR (600 MHz, CDCl3) δ[ppm] = 3.92 (s, 9H), 6.99 (d, J = 9 Hz, 6H), 8.57 (d, J = 9 Hz, 6H) MS (MALDI-TOF): 492.65 [calcd:491.17]

[0139] The organic compound p37-118 is represented by the following formula (23). [ka] The synthesis of the organic compound p37-118 was carried out as follows: Ciameric acid (623 mg, 2.26 mmol) was dissolved in m-xylene (20 mL), and diphenylamine (420 mg, 2.49 mmol) was added at room temperature. After stirring for 2.5 hours, the temperature was raised to 50°C and stirred for a further 2 hours. The mixture was cooled to 0°C, aluminum chloride (904 mg, 6.8 mmol) was added, and after stirring at room temperature for 17 hours, water was added. Subsequently, chloroform was added after 30 minutes, the organic layer was separated, dried over sodium sulfate, concentrated, and purified by column (CHCl3 100%) to obtain the target product. The obtained yellow solid organic compound p37-118 amounted to 318 mg (0.58 mmol, 25.6%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 2.34 (s, 6H), 2.63 (s, 6H), 7.03 (br s, 4H), 7.28 - 7.31 (m, 6H), 7.38 (t, J = 7.8 Hz, 4H), 7.97 (d, J = 8.4 Hz, 2H) MS (MALDI-TOF): 549.94 [calcd:548.24]

[0140] The organic compound p139-139 is represented by the following formula (24). [ka] The synthesis of organic compound p139-139 was carried out as follows: 138 mg, 0.5 mmol of ciameryl chloride was dissolved in tetrahydrofuran (2 mL), and methanol (2 mL) and N,N-diisopropylethylamine (425 mL, 2.5 mmol) were added under a nitrogen atmosphere at room temperature. After 20 minutes, the temperature was raised to 60°C and stirred for 24 hours. After returning to room temperature and adding water, the precipitate was filtered and vacuum-dried. It was dissolved in chloroform, filtered with silica gel, and washed with chloroform to obtain the target product. The obtained white solid organic compound p139-139 amounted to 35 mg (0.133 mmol, 27%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 4.10 (s, 9H) MS (MALDI-TOF): 264.30 [calcd:263.08]

[0141] The organic compound p141-141 is represented by the following formula (25). [ka] The synthesis of organic compound p141-141 was carried out as follows: Intermediate I4 (228 mg, 0.5 mmol) represented by formula (26) below was dissolved in 1-propanol (3 mL), and 2,4,6-trimethylpyridine (217 mL, 1.65 mmol) was added under an argon atmosphere at room temperature. After stirring for 10 minutes, the temperature was raised to 90°C and stirred for 3 hours. After returning to room temperature and adding water, the mixture was extracted with chloroform, the organic layer was dried over sodium sulfate, and concentrated. Purification was performed by column chromatography (AcOEt: CHCl3 = 5:95 - 15:85) to obtain the target product. The obtained white solid organic compound p141-141 amounted to 107 mg (0.31 mmol, 62%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.00 (t, 9H), 1.80 (s, 6H), 4.43 (t, 6H) MS (MALDI-TOF): 348.50 [calcd:347.17] [ka]

[0142] The synthesis of intermediate I4 was carried out as follows: Ciameryl chloride (314 mg, 1.1 mmol) was dissolved in toluene (5 mL), and 3,5-dimethylpyrazole (362 mg, 3.8 mmol) and N,N-diisopropylethylamine (969 mL, 5.7 mmol) were added under an argon atmosphere at room temperature. After 40 minutes, the temperature was raised to 70°C, and then to 90°C after another 20 minutes, and the mixture was stirred for 2 hours. After returning to room temperature and adding water, the mixture was extracted with chloroform, and the organic layer was dried over sodium sulfate and concentrated. Purification was performed by column chromatography (MeOH: CHCl3 = 1:99 - 10:90) to obtain the target product. The obtained pale yellow solid intermediate I4 amounted to 490 mg (1.08 mmol, 94%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 2.34 (s, 9H), 2.76 (s, 9H), 6.11 (s, 3H) MS (MALDI-TOF): 456.54 [calcd:455.20]

[0143] The organic compound p142-142 is represented by the following formula (27). [ka] The synthesis of organic compound p142-142 was carried out as follows: 358 mg, 1.3 mmol of ciameryl chloride was dissolved in tetrahydrofuran (3 mL), and 3 mL of 1-butanol and 1.1 mL, 6.5 mmol of N,N-diisopropylethylamine were added under an argon atmosphere at room temperature. After addition, the temperature was raised to 70°C, and then to 90°C after 2 hours, and stirred for 1.5 hours. After returning to room temperature and adding water, the mixture was extracted with chloroform, the organic layer was dried over sodium sulfate, and concentrated. Purification was performed by column chromatography (AcOEt:CH2Cl2 = 1:99 - 10:90) to obtain the target product. The obtained white solid organic compound p142-142 amounted to 374 mg (0.96 mmol, 74%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 0.95 (t, 9H), 1.45 (tq, 6H), 1.76 (tt, 6H), 4. 47 (t, 6H), MS (MALDI-TOF): 390.64 [calcd:389.22]

[0144] The organic compound p140-140 is represented by the following formula (28). [ka] The synthesis of the organic compound p140-140 was carried out as follows: 456 mg, 1.65 mmol of ciameryl chloride was dissolved in tetrahydrofuran (5 mL), and 5 mL of ethanol and 1.4 mL, 8.3 mmol of N,N-diisopropylethylamine were added under an argon atmosphere at room temperature. After 2 hours, the temperature was raised to 80°C and stirred for 17 hours. After returning to room temperature and adding water, the mixture was extracted with dichloromethane, the organic layer was dried over sodium sulfate, and concentrated. Purification was performed by column chromatography (AcOEt:CH2Cl2 = 5:95 - 15:85) to obtain the target product. The obtained white solid organic compound p140-140 amounted to 172 mg (0.56 mmol, 34%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.41(t, 9H), 4.53(q, 6H) MS (MALDI-TOF): 306.47 [calcd:305.12]

[0145] The organic compound p162-162 is represented by the following formula (29). [ka] The synthesis of organic compound p162-162 was carried out as follows: 221 mg, 0.8 mmol of ciameryl chloride was dissolved in toluene (5 mL), and ethanethiol (592 mg, 4.0 mmol) and N,N-diisopropylethylamine (680 mL, 5.7 mmol) were added under an argon atmosphere at room temperature. After 30 minutes, the temperature was raised to 35°C and stirred for 17 hours. After returning to room temperature and adding water, the mixture was extracted with chloroform, the organic layer was dried over sodium sulfate, and concentrated. Purification was performed by column chromatography (AcOEt:CH2Cl2=0:100-5:95) to obtain the target product. The obtained white solid organic compound p162-162 amounted to 234 mg (0.66 mmol, 83%). 1 H NMR (600 MHz, CDCl3) δ[ppm] = 1.37 (t, 9H), 3.16(q, 6H) MS (MALDI-TOF): 354.43 [calcd:353.06]

[0146] The organic compound p65-166 is represented by the following formula (30). [ka] The synthesis of organic compounds p65-166 was carried out as follows: To a solution of intermediate I3 (608 μL, 4.3 mmol) in dichloromethane (11.8 mL), aluminum chloride (616 mg, 4.6 mmol) was added at room temperature and the mixture was stirred for 40 minutes. A solution of compound 2 in dichloromethane (12 mL) was slowly added and the mixture was stirred at room temperature for 20.5 hours. A 1 M aqueous sodium hydroxide solution (16 mL) was added at 0°C and the mixture was stirred at room temperature for 4 hours, after which it was filtered using Celite. After adding a 20% aqueous sodium chloride solution to the reaction mixture, the organic layer was separated, dried over anhydrous sodium sulfate, concentrated, and purified by column chromatography (CH2Cl2- CH2Cl2: MeOH = 9:1) to obtain the crude product (117 mg). The crude product was purified by preparative column chromatography (SunFire, Hexane / siRNA = 82:18), and organic compound p65-166 was obtained as the third peak. The amount of the obtained yellow solid organic compound p65-166 was 13.8 mg (0.025 mmol, 2.3%). 1H NMR (600 MHz, CDCl3) δ[ppm] = 0.80-0.92 (br, 2H), 1.20-1.38 (br, 2H), 1.38-1.50 (m, 2H), 1.66-1.76 (br, 2H), 2.00-2.08 (br, 2H), 2.31 (s, 6H), 2.32 (s, 6H), 3.78 (s, 6H), 3.89-3.98 (br, 1H), 6.57 (s, 2H), 6.63 (s, 2H)

[0147] The crude sample was purified using a preparative column (SunFire, Hexane / SiO2 = 82:18), and the second peak was obtained from the organic compound shown in equation (31) below. The amount of the obtained yellow solid organic compound was 22.4 mg (0.040 mmol, 3.8%). 1H NMR (600 MHz, CDCl3) δ[ppm] = 0.80-0.92 (br, 2H), 1.20-1.38 (br, 2H), 1.38-1.50 (m, 2H), 1.68-1.77 (br, 2H), 2.00-2.10 (br, 2H), 2.31 (s, 3H), 2.32 (s, 3H), 2.41 (s, 6H), 3.78 (s, 3H), 3.79 (s, 3H), 3.86-3.98 (br, 1H), 6.58 (s,1H), 6.59 (s, 2H), 6.64 (s, 1H) [ka]

[0148] [Additional Notes] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Industrial applicability]

[0149] This invention can be used as a light-emitting material.

Claims

[Claim 1] The invention described in the specification.

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