Nonlinear optical chromophores having short-chain bridge structures, low optical loss materials containing the same and methods for preparing the same

Abstract

A nonlinear optical chromophore having a short chain bridge between the donor and acceptor is provided. The chromophore has a shortened λ max Electro-optic films prepared from the provided nonlinear optical chromophores have enhanced transparency to wavelengths outside the narrow absorption band, low optical loss, and high thermal and photostability.

Description

[Technical field]

[0001] The present invention relates to a nonlinear optical chromophore having a short-chain bridge structure, a low optical loss material containing the same, and a method for preparing the same. [Background technology]

[0002] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 296,579, filed January 5, 2022, the entire contents of which are incorporated herein by reference.

[0003] (Background technology) Nonlinear optical (NLO) chromophores provide electro-optical (EO) activity in poled electro-optical polymer devices. For many years, electro-optical polymers have been investigated as a replacement for inorganic materials such as lithium niobate in electro-optical devices. Electro-optical devices include, for example, external modulators for telecommunications, RF photonics, optical interconnects, etc. Polymer electro-optical materials have shown great potential for core applications in a wide range of next-generation systems and devices, such as phased array radar, satellite and fiber telecommunications, cable television (CATV), optical gyroscopes for aviation guidance and missile guidance applications, electronic countermeasure (ECM) systems, backplane interconnects for high-speed computing, ultrafast analog-to-digital conversion, mine detection, radio frequency photonics, spatial light modulation, and all-optical (light-switching-light) signal processing.

[0004] A large number of NLO molecules (chromophores) have been synthesized that exhibit high molecular electro-optic properties. Due to the involvement of dipoles in materials processing, the product of molecular dipole moment (μ) and hyperpolarizability (β) is often used as a measure of molecular electro-optic performance. See WO 00 / 09613 (Dalton et al., "New Class of High Hyperpolarizability Organic Chromophores and Process for Synthesizing the Same").

[0005] Nevertheless, it is possible to calculate the hyperpolarizability of a microscopic molecule (β) by comparing it to the hyperpolarizability of a macroscopic material (χ 2 ) have encountered great challenges. The molecular subcomponents (chromophores) must be incorporated into NLO materials that exhibit (i) a high degree of macroscopic nonlinearity and (ii) sufficient temporal, thermal, chemical, and photochemical stability. High electro-optic activity and the stability of the electro-optic activity, also called "temporal stability," are important for commercially viable devices. The electro-optic activity can be increased in electro-optic polymers by increasing the concentration of the nonlinear optical chromophore in the host polymer and by enhancing the electro-optic properties of the chromophore. However, some techniques to increase the chromophore concentration risk decreasing the poling efficiency and temporal stability. Simultaneously solving these dual problems is considered the final obstacle to the widespread practical application of EO polymers in many devices and systems.

[0006] High material hyperpolarizability (χ 2 The creation of NLO chromophores is limited by the poor social character of the NLO chromophores. Commercially available materials must incorporate the chromophores at high molecular densities with the required molecular moments statistically oriented along a single material axis. To achieve such organization, the charge-transfer (dipole) properties of the NLO chromophores are typically exploited. Here, an external electric field is applied during material processing that results in local low-energy conditions that favor non-centrosymmetric order. Unfortunately, even at moderate chromophore densities, the molecules form multi-molecular dipole-coupled aggregates (centrosymmetric) that cannot be broken up with realistic electric field energies. To overcome this difficulty, the incorporation of anti-social dipolar chromophores into cooperative material structures has typically been achieved by constructing physical barriers (e.g., anti-packing steric groups) that limit the association between nearby molecules.

[0007] Thus, it has often been considered advantageous in the art to produce nonlinear optical chromophore-containing materials that exhibit high glass transition temperatures (Tg). Materials with high glass transition temperatures exhibit improved thermal stability and maintain macroscopic electro-optical properties to a greater extent than materials with lower glass transition temperatures. Materials with high glass transition temperatures also exhibit desirable macroscopic optical properties, thermal stability, and shorter wavelength absorption maxima, i.e., λ max It is also advantageous to prepare nonlinear optical chromophores having the formula: Summary of the Invention [Means for solving the problem]

[0008] The present invention is generally directed to nonlinear optical chromophores having a short chain bridge between the donor and acceptor. Various embodiments of the present invention include nonlinear optical chromophores having a short chain bridge between the donor and acceptor, which chromophores have a shortened λ max Various embodiments of the present invention include a nonlinear optical chromophore having a short chain bridge between a donor and an acceptor in a polar solvent, the chromophore having a λ value of 800 nm or less. max In some instances, the nonlinear optical chromophore has a λ value of 750 nm or less. max In other examples, the nonlinear optical chromophore has a λ value of 700 nm or less, 650 nm or less, or 600 nm or less. max In certain embodiments, the nonlinear optical chromophore having a short chain bridge between the donor and acceptor has a shortened λ max Denote the value of λ max In an exemplary embodiment, the nonlinear optical chromophore can have a narrow absorption band at λ (e.g., about 30-800 nm or less). max In other particular embodiments, the nonlinear optical chromophore can have a narrow absorption band (e.g., about 30-100 nm or less) at λ of the chromophore analog in a nonpolar solvent. max Based on Δλ max It is characterized by:

[0009] In the embodiments described herein, λ maxValues ​​of λ outside the ranges described herein may be used. max For example, various nonlinear optical chromophore embodiments provide transparency over 800 nm, which has applications in 1) short-range local area networks, 2) free-space fiber optic communications and optical interconnects in combination with LEDs or semiconductor lasers, and 3) as active materials in terahertz (THz) applications.

[0010] Various embodiments of the present invention include nonlinear optical chromophores with short chain bridges between donors and acceptors, which can exhibit reduced optical loss and provide higher transparency at various wavelengths. Additionally, various embodiments of the present invention have optimized properties of (1) higher r33 (electro-optic coefficient) at various wavelengths, (2) higher Tg (glass transition temperature), (3) particularly high thermal stability, and (4) high light stability.

[0011] Various embodiments of the present invention relate to a compound represented by the general formula (I): D-Π-A (I) wherein D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D; and Π represents a Π-bridge between A and D, the Π-bridge comprising a carbon chain covalently bonding A and D and separating A and D, the carbon chain length between A and D being 2-4 carbon atoms, the 2-4 carbon atom chain comprising up to two carbon-carbon double bonds and up to four pendant substituents, and two or more of the pendant substituents can form a ring structure with the 2-4 carbon atom chain.

[0012] Various embodiments of the present invention include compounds of the general formula (I a )

[0013] [ka]

[0014] wherein D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D; x is 1 or 2; and each R is independently hydrogen, an alkyl group, an aryl group, an alkyl or aryl group linked by sulfur or oxygen, an aryl group (optionally with a diamondoid group) linked directly by a carbon-carbon bond (e.g., adamantyl anisole), a halogen, a halogenated alkyl group, a halogenated aryl group, a branched or unbranched, optionally heteroatom-containing C1-C4 substituent, or a diamondoid-containing group. In various embodiments, one or more of the R substituents can represent a moiety having from 1 to 4 carbon atoms. In various embodiments, one or more of the R substituents can represent a thiophene moiety.

[0015] In various embodiments of the invention, the electron donating group comprises a substituted or unsubstituted quinolinyl group.In various embodiments of the invention, the π-bridge comprises a pendant substituent that contains a thiophene.

[0016] In certain embodiments, a composition of nonlinear optical chromophores for preparing electro-optic films exhibiting one or more enhanced optical properties is provided, the nonlinear optical chromophores having a λ of 800 nm or less. max value, and the one or more enhanced optical properties is the electro-optic coefficient of the electro-optic film. In one exemplary embodiment, the nonlinear optical chromophore has the general formula (I) D-Π-A, where D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D, Π represents a Π-bridge between A and D, the Π-bridge including a carbon chain covalently bonding A and D and separating A and D, the carbon chain length between A and D being 2-4 carbon atoms, the 2-4 carbon atom chain including up to 2 carbon-carbon double bonds and up to 4 pendant substituents. In this and other examples, a high boiling point aprotic polar solvent can be used, which is adapted to promote high material hyperpolarizability of the electro-optic film.

[0017] Other aspects, features and advantages will become apparent from the following disclosure, including the detailed description, the preferred embodiments, and the appended claims.

[0018] The foregoing summary, and the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the accompanying drawings, in which there is shown, for the purpose of illustrating the invention, an embodiment which is presently preferred, but it should be understood that the invention is not limited to the precise arrangements and equipment shown. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a spectrograph 100 showing the absorption of an exemplary short-chain bridged chromophore of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 101 shows the absorption of an exemplary short-chain bridged chromophore of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 102 shows the absorption of an exemplary short-chain bridged chromophore of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Diagram 2] FIG. 2 is a spectrograph 200 showing the absorption of the exemplary short-chain bridged chromophore of the second example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 201 shows the absorption of the exemplary short-chain bridged chromophore of the second example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 102 shows the UV-Vis absorption spectrum of the exemplary short-chain bridged chromophore of the second example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Diagram 3] FIG. 3 is a spectrograph 300 showing the absorption of the exemplary short-chain bridged chromophore of the third example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 301 shows the absorption of the exemplary short-chain bridged chromophore of the third example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 302 shows the absorption of the exemplary short-chain bridged chromophore of the third example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Figure 4]FIG. 4 is a spectrograph 400 showing the absorption of the exemplary short-chain bridged chromophore of the fourth example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 401 shows the absorption of the exemplary short-chain bridged chromophore of the fourth example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 402 shows the absorption of the exemplary short-chain bridged chromophore of the fourth example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Diagram 5] FIG. 5 is a spectrograph 500 showing the absorption of the exemplary short-chain bridged chromophore of the fifth example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 501 shows the absorption of the exemplary short-chain bridged chromophore of the fifth example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 502 shows the absorption of the exemplary short-chain bridged chromophore of the fifth example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Figure 6] FIG. 6 is a spectrograph 600 showing the absorption of the exemplary short-chain bridged chromophore of the sixth example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 601 shows the absorption of the exemplary short-chain bridged chromophore of the sixth example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 602 shows the absorption of the exemplary short-chain bridged chromophore of the sixth example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Figure 7] FIG. 7 is a spectrograph 700 showing the absorption of the exemplary short-chain bridged chromophore of the seventh example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 701 shows the absorption of the exemplary short-chain bridged chromophore of the seventh example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 702 shows the absorption of the exemplary short-chain bridged chromophore of the seventh example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. [Figure 8]FIG. 8 is a spectrograph 800 showing the absorption of the exemplary short-chain bridged chromophore of the eighth example of Formula 1a in two separate solvents in the UV-Vis band, where a first curve 801 shows the absorption of the exemplary short-chain bridged chromophore of the eighth example of Formula 1a in 1,4-dioxane solvent in the UV-Vis band and a second curve 802 shows the absorption of the exemplary short-chain bridged chromophore of the eighth example of Formula 1a in dichloromethane (DCM) solvent in the UV-Vis band. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] As used herein, the singular terms "a" and "the" are synonymous with and used interchangeably with "one or more" and "at least one," unless the description and / or context clearly indicates otherwise. Thus, for example, a reference to "a polymer" or "the polymer" herein or in the appended claims can refer to a single polymer or multiple polymers. As a further example, a reference to "a solvent" or "the solvent" herein or in the appended claims can refer to a single solvent or a mixture of multiple solvents. Additionally, unless otherwise indicated, all numerical values ​​are understood to be modified by the word "about."

[0021] As used herein, the term "nonlinear optical chromophore" (NLOC) refers to a molecule or portion of a molecule that produces a nonlinear optical effect when illuminated with light. A chromophore is any molecular unit that produces a nonlinear optical effect upon interaction with light. The desired effect can occur at resonant or nonresonant wavelengths. The activity of a particular chromophore in a nonlinear optical material is manifested as a hyperpolarizability, which is directly related to the molecular dipole moment of the chromophore. Various embodiments of the NLO chromophores of the present invention are structures that are useful for producing NLO effects.

[0022] First-order hyperpolarizability (β) is one of the most common and useful NLO properties. Higher-order hyperpolarizabilities are useful in other applications, such as all-optical (light-switching-light) applications. To determine whether a material, such as a compound or polymer, contains a nonlinear optical chromophore with first-order hyperpolarizability and a sufficient value of the electro-optic coefficient (r33, which is a function of β), the following test can be performed: First, a thin film of the material is placed in an electric field to align the dipoles. This can be done, for example, by sandwiching a thin film of the material between electrodes, such as an indium-tin-oxide (ITO) substrate, a thin gold film, or a thin silver film.

[0023] The nonlinear optical chromophores according to the embodiments herein have a short bridge between the donor and acceptor, and the chromophore ends in excess of λ max Denote the value of λ max For example, a nonlinear optical chromophore having a short chain bridge between the donor and acceptor can have a narrow absorption band at λ (e.g., about 50-800 nm or less). max As another example, a nonlinear optical chromophore with a short chain bridge between the donor and acceptor can have a narrow absorption band (approximately 50-100 nm or less) at λ max It can have a narrow absorption band (approximately 30 to 50 nm or less) in the

[0024] Δλ max is the λ of the nonlinear optical chromophore in a standard polar solvent (e.g., DCM). max and λ of the analogues in non-polar solvents (e.g., 1,4-dioxane). max The lower polarity solvent (1,4-dioxane) stabilizes the chromophore in its neutral ground state, while the higher polarity solvent (DCM) stabilizes the charge-transfer state of the chromophore. The more readily charge-transfer occurs, the more "polarizable" the chromophore is, and the more active it is. Here, it has been found that longer wavelengths are directly proportional to lower energy. That is, the Δλ between the two solvents maxThe larger r, the less energy is required to achieve the charge transfer state. Furthermore, r, which is measured experimentally and is equal to the response of the passing light to an applied electric field, has a general correlation with Δλ, with a larger Δλ generally correlating with a larger r. Thus, Δλ max is a characteristic of the "strength" of the electro-optic activity of a chromophore. For example, the Δλ max is about 30 nm or more, it correlates with a sufficiently large r33. max is about 35 nm or more.

[0025] Referring to FIG. 1, the absorption of the chromophore (IU4128A) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. The λ max is 653.45 nm in dichloromethane (DCM) and 622.40 nm in 1,4-dioxane.

[0026] Referring to Figure 2, the absorbance of the chromophore (IV8422) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. max is 661.97 nm in dichloromethane (DCM) and 595.77 nm in 1,4-dioxane.

[0027] Referring to Figure 3, the absorbance of the chromophore (KM4042) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. The λ max is 662 nm in dichloromethane (DCM) and 627 nm in 1,4-dioxane.

[0028] Referring to Figure 4, the absorbance of the chromophore (KM4043) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. max is 630 nm in dichloromethane (DCM) and 596 nm in 1,4-dioxane.

[0029] Referring to Figure 5, the absorbance of the chromophore (KM4044) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. max is 617 nm in dichloromethane (DCM) and 581 nm in 1,4-dioxane.

[0030] Referring to Figure 6, the absorbance of the chromophore (KM4051) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. max is 661 nm in dichloromethane (DCM) and 626 nm in 1,4-dioxane.

[0031] Referring to Figure 7, the absorbance of the chromophore (KM4060) was measured in two different solvents. The concentration of the sample was 14 μg / mL in 1,4-dioxane and 8.5 μg / mL in dichloromethane (DCM). max is 631 nm in dichloromethane (DCM) and 595 nm in 1,4-dioxane.

[0032] Referring to Figure 8, the absorbance of the chromophore (KM4084) was measured in two separate solvents. The concentration of the sample in each solvent was 17 μg / mL. max is 627 nm in dichloromethane (DCM) and 593 nm in 1,4-dioxane.

[0033] The λ of short-chain bridged chromophores in Figures 1 to 8 max and Δλ max The data is summarised as follows:

[0034] [Table 1]

[0035] To generate the poling field, a potential is applied to the electrodes while the material is heated to near its glass transition temperature (Tg). After a suitable time, the temperature is gradually decreased while maintaining the poling field. Alternatively, the material can be poled by corona poling, where a charged needle at a suitable distance from the material film provides the poling field. In either case, dipoles in the material tend to align with the electric field. Various embodiments according to the present invention can or may include electro-optic materials having a material glass transition temperature of 100° C. or higher, 125° C. or higher, 150° C. or higher, or higher.

[0036] The nonlinear optical properties of the polarizing material are then examined as follows: polarized light (often from a laser) is passed through the poled material and a subsequent polarizing filter to a light intensity detector. If the intensity of light received by the detector changes when the potential applied to the electrodes is changed, the material incorporates a nonlinear optical chromophore with an electro-optically variable refractive index. A more detailed discussion of techniques for measuring the electro-optic constants of poled films incorporating nonlinear optical chromophores can be found in Chia-Chi Teng, Measuring Electro-Optic Constants of a Poled Film, in Nonlinear Optics of Organic Molecules and Polymers, Chp. 7, 447-49 (Hari Singh Nalwa & Seizo Miyata eds., 1997), which is hereby incorporated by reference in its entirety. However, in the event of any disclosure or definition that conflicts with this specification, the disclosure or definition in this specification shall take precedence.

[0037] The relationship between the change in applied potential and the change in refractive index of a material is expressed as the electro-optic (OE) coefficient r33. This effect is commonly referred to as the electro-optic effect (EO effect). Devices containing materials whose refractive index changes in response to a change in applied potential are called electro-optic (EO) devices. In compositions having short-chain bridged chromophores as described herein, high EO coefficients of greater than 30 pm / V (e.g., measured at 980 nm) or greater than 20 pm / V (e.g., measured at 1310 nm) can be achieved.

[0038] The compositions having short-chain bridged chromophores described herein can also exhibit reduced optical loss. The optical loss of the various embodiments described herein can be less than 2 dB / cm. Furthermore, the compositions described herein can provide greater transparency at wavelengths outside the absorption bands of the various embodiments described herein. In addition, the compositions described herein can also exhibit extremely high thermal stability (characterized by a decomposition temperature greater than 250° C.) and high photostability as measured by degradation of photo-optic materials under broadband light and ambient conditions.

[0039] Second-order hyperpolarizability (γ) or third-order susceptibility (χ (3)) is a common measure of third-order NLO activity. There are several ways to measure these properties, but the degenerate four-wave mixing (DFWM) method is very common. See CW Thiel, "For-wave Mixing and Its Applications", http: / / www.physics.montana.edu.students.thiel.docs / FWMixing.pdf, which is incorporated herein by reference in its entirety. A method for evaluating the third-order NLO properties of thin films known in the art as the degenerate four-wave mixing (DFWM) method can be used, see US Patent Publication No. 2012 / 0267583, which is incorporated herein by reference in its entirety. In FIG. 4 of US Patent Publication No. 2012 / 0267583, beams 1 and 2 are picosecond coherent pulses that are absorbed in an NLO film deposited on a glass substrate. Beam 3 is a weaker, slightly delayed beam with the same wavelength as beams 1 and 2. Beam 4 is the result of wave mixing diffracted off the transient holographic grating produced by the interference of Beam 1 and Beam 2 in the NLO material of the film. Beam 3 can be a "control" beam at telecommunications wavelengths that produces a "signal" beam at a frequency not absorbed by the NLO material.

[0040] Nonlinear optical chromophores suitable for use in accordance with various embodiments of the present invention have the general formula (I): D-Π-A (I) (wherein D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D; and Π represents a Π-bridge between A and D). The terms electron donating group (donor or "D"), Π-bridge (bridging group or "Π"), and electron accepting group (acceptor or "A"), as well as general synthetic methods for forming D-Π-A chromophores, are known in the art and are described, for example, in U.S. Pat. Nos. 5,670,091, 5,679,763, 6,090,332, 6,716,995, and U.S. Patent Application No. 17 / 358,960, filed June 25, 2021, which are incorporated herein by reference in their entireties.

[0041] An acceptor is an atom or group of atoms with a low reduction potential that can accept electrons from a donor through a π bridge. Because the acceptor (A) has a larger electron affinity than the donor (D), at least in the absence of an external electric field, the chromophore is generally polarized in the ground state, with a relatively high electron density on the acceptor (A). Typically, the acceptor group contains at least one electronegative heteroatom that is part of a π bond (double or triple bond), and a resonance structure can be drawn in which the electron pair of the π bond is transferred to the heteroatom, simultaneously reducing the multiplicity of the π bond (i.e., the double bond is formally converted to a single bond or the triple bond is formally converted to a double bond) and the heteroatom acquires a formal negative charge. The heteroatom may be part of a heterocycle. Exemplary acceptor groups include, but are not limited to, -NO2, -CN, -CHO, COR, CO2R, -PO(OR)3, -SOR, -S2R, and -S3R, where R is alkyl, aryl, or heteroaryl. The total number of heteroatoms and carbons in the acceptor group is about 30, and the acceptor group may be further substituted with alkyl, aryl, and / or heteroaryl.

[0042] Suitable electron accepting groups "A" (also referred to in the literature as electron withdrawing groups) for nonlinear optical chromophores that can be used in accordance with various embodiments of the present invention include those described in U.S. Patent Application Publication Nos. 2007 / 0260062, 2007 / 0260063, 2008 / 0009620, 2008 / 0139812, 2009 / 0005561, and 2012 / 0267583 (collectively the "prior published documents"), which are incorporated herein by reference in their entireties, and in U.S. Patent Nos. 6,584,266, 6,392, 6,413, 6,512, 6,522, 6,536, 6,540, 6,552, 6,562, 6,572, 6,582, 6,592, 6,671, 6,711, 6,722, 6,736, 6,742, 6,752, 6,762, 6,826, 6,912, 6,922, 6,932, 6,822, 6,912, 6,922, 6,932, 6,742, 6,822, 6,93 ... Nos. 3,190, 6,448,416, 6,44,830, 6,514,434, 5,044,725, 4,795,664, 5,247,042, 5,196,509, 4,810,338, 4,936,645, 4,767,169, 5,326,661, 5,187,234, 5,170,461, 5,133,037, 5,106,211, and 5,006,285.

[0043] In nonlinear optical chromophores suitable for use in accordance with various embodiments of the present invention, suitable electron accepting groups are represented by the general formula (II a ):

[0044] [ka]

[0045] (In the formula, R 2 and R 3 are each independently H, substituted or unsubstituted C1-C 10 Alkyl, substituted or unsubstituted C2-C 10Alkenyl, substituted or unsubstituted C2-C 10 Alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted alkylaryl, substituted or unsubstituted carbocyclic groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted cyclohexyl, and (CH2) n -O-(CH2) n where n is 1 to 10. As used herein, the following symbols represent a point of attachment to another portion of a larger molecular structure.

[0046] [ka]

[0047] In various preferred embodiments, R 2 and R 3 One or both of R represent halogen substituted moieties. Halogen substitution may refer to mono-, di-, tri- and higher degrees of substitution. In various embodiments, R 2 and R 3 One of R represents a halogen substituted alkyl moiety and the other represents an aromatic moiety. 2 and R 3 one represents a halogen substituted aromatic moiety and the other represents an alkyl moiety. In various embodiments, the electron accepting group can be:

[0048] [ka]

[0049] In various embodiments, the electron accepting group can be:

[0050] [ka]

[0051] In various embodiments, the electron accepting group can be:

[0052] [ka]

[0053] The donor comprises an atom or group of atoms with a low oxidation potential, which can donate electrons to the acceptor "A" through a π bridge. Since the donor (D) has a smaller electron affinity than the acceptor (A), at least in the absence of an external electric field, the chromophore is generally polarized in the ground state and has a relatively low electron density on the donor (D). Typically, the donor group comprises at least one heteroatom having an unshared electron pair capable of conjugating with the p orbital of the atom directly bonded to the heteroatom, and a resonance structure can be drawn in which the heteroatom formally gains a positive charge by transferring the unshared electron pair to a bond with the p orbital of the atom directly bonded to the heteroatom, thereby formally increasing the bond multiplicity between the heteroatom and the atom directly bonded to the heteroatom (i.e., a single bond is formally converted to a double bond or a double bond is formally converted to a triple bond). The p orbital of the atom directly bonded to the heteroatom may be vacant or may be part of a multiple bond with another atom other than the heteroatom. The heteroatom may be a substituent of an atom having a pi bond or may be within a heterocycle. Exemplary donor groups are R2N-, and R n X 1 - (wherein R is alkyl, aryl or heteroaryl; and X 1 is O, S, P, Se or Te, and n is 1 or 2. The total number of heteroatoms and carbons in the donor group can be about 30, and the donor group can be further substituted with alkyl, aryl or heteroaryl.

[0054] Suitable electron donating groups "D" for nonlinear optical chromophores that can be used in accordance with various embodiments of the present invention include those described in U.S. Patent Application Publication Nos. 2007 / 0260062, 2007 / 0260063, 2008 / 0009620, 2008 / 0139812, 2009 / 0005561, and 2012 / 0267583 (collectively, the "Prior Published Documents"), which are incorporated herein by reference in their entireties, and in U.S. Patent Nos. 6,584,266, 6,393,190, 6,448,416, and 6,44,830, which are incorporated herein by reference in their entireties. Nos. 6,514,434, 5,044,725, 4,795,664, 5,247,042, 5,196,509, 4,810,338, 4,936,645, 4,767,169, 5,326,661, 5,187,234, 5,170,461, 5,133,037, 5,106,211, and 5,006,285, as well as those described in U.S. Patent Application Serial No. 17 / 358,960, filed June 25, 2021, the entirety of which is incorporated herein by reference.

[0055] In various embodiments, the electron donating group can include quinolinyl groups, which may be substituted or unsubstituted, including hydro and alkyl substituents, aryl substituents, and combinations thereof.Such quinolinyl groups can have one or more diamondoid groups covalently bonded thereto.For example, the electron donating group can include alkoxyphenyl-substituted quinolones, such as:

[0056] [ka]

[0057] Or, for example, the electron donating group can include an aromatic nitrogen-containing group such as:

[0058] [ka]

[0059] A "π-bridge" includes an atom or group of atoms through which electrons can be delocalized from an electron donor (defined above) to an electron acceptor (defined above) via orbitals of atoms in the bridge. Typically, the orbitals are located at doubly bonded carbon atoms (sp 2 ) or p orbitals on triple bonded carbon atoms (sp). Additionally, the orbitals may be p orbitals on atoms such as boron or nitrogen. Additionally, the orbitals may be p, d or f organometallic or hybrid organometallic orbitals. In this specification, the bridge atoms containing the orbitals where the electrons are delocalized are referred to as "critical atoms". The number of critical atoms in the bridge is 1 to about 30. The critical atoms may be substituted with organic or inorganic groups. The substituents are selected with a view to improving the solubility of the chromophore in the polymer matrix, improving the stability of the chromophore, or for another purpose.

[0060] In accordance with various embodiments of the nonlinear optical chromophores described herein, the Π-bridge comprises a carbon chain separating the electron donating and electron accepting groups, the length of the chain separating them being from 2 to 4 carbon atoms. The Π-bridge can further comprise one or more pendant substituents, the atoms of which are not included in the chain length count. In various embodiments, the two or more pendant substituents can form a ring structure together with the 2 to 4 carbon atom bridge. For example, the Π-bridge in the nonlinear optical chromophores according to various embodiments of the present invention can be represented by the general formula (I a )-(Ih wherein A, D, x and each R are as defined herein above:

[0061] [ka]

[0062] Nonlinear optical chromophores according to various embodiments of the present invention have an absorption maximum (λ ) of 800 nm or less. max ) The nonlinear optical chromophores according to various embodiments of the present invention exhibit excellent second order optical properties and have excellent thermal stability. The nonlinear optical chromophores according to various embodiments of the present invention can be used mixed with one or more host polymers or matrix materials and / or one or more solvents, or can be used neat (i.e., without host polymer or solvent). The nonlinear optical chromophores according to various embodiments of the present invention can be formed into thin films for electro-optical devices and poled according to various processes known in the art for producing ordered thin films.

[0063] The invention will now be described in further detail with reference to the following non-limiting examples. EXAMPLES

[0064] Example 1: Chromophore IU4128A (Synthesis of triphenyl(p-tolyl)silane)

[0065] [ka]

[0066] A dry RB flask (1) was charged with 1-bromo-4-methyl-benzene (9.93 mL, 0.0807 mol) and THF (200 mL) and cooled to −78° C. in a dry ice / acetone bath. n-Butyllithium (2.50 mol / L, 32.3 mL, 0.0807 mol) was added at a rate (5 mL increments) such that the temperature did not rise above −55° C. and the reaction was stirred under nitrogen for 2 hours.

[0067] In a separate RB flask (2), evacuated and filled with nitrogen three times, charged with triphenylsilyl chloride (26.2 g, 0.0888 mol), evacuated / filled with nitrogen three times, and stirred under reduced pressure for 1 h at 60° C. Flask (2) was cooled, filled with nitrogen, THF (100 mL) was added, and cooled to −78° C.

[0068] The contents of Flask 2 were cannulated into Flask 1 in a steady dropwise fashion, allowing the temperature to rise to 5° C. The reaction was stirred under nitrogen and allowed to warm slowly to room temperature.

[0069] The reaction was diluted with DCM, washed with water then brine, dried over MgSO4 and evaporated to give a white solid which was stirred in hexane for 1 h and filtered / washed with hexane (500 mL).

[0070] Triphenyl(p-tolyl)silane (25.4 g, 0.0725 mol, 89.8% yield) was obtained as a white powder.

[0071] (Wahl-Ziegler bromination reaction of triphenyl(p-tolyl)silane)

[0072] [ka]

[0073] A RB flask was charged with triphenyl(p-tolyl)silane (0 mmol / L, 0 mL, 0.0394 mol), N-bromosuccinimide (7.36 g, 0.0413 mol), 400 mL DCM, and 2-[(E)-(1-cyano-1-methyl-ethyl)azo]-2-methyl-propanenitrile (0.323 g, 0.00197 mol). The reaction was refluxed under nitrogen overnight. TLC showed quantitative conversion to the bromide. The reaction was washed with water, then brine, dried over MgSO4, and evaporated to give a brown powder. This was triturated in hexane and filtered to give a first fraction of 13.8 g. The filtrate was evaporated to give a second fraction of 3.49 g. The hexane fraction was chromatographed eluting with hexane / ethyl acetate (3-5%). The appropriate fractions were combined and evaporated to give 885mg of a very white granular powder.

[0074] 4-(Bromomethyl)phenyl]-triphenylsilane (14.7 g, 0.0342 mol, 87.0% yield) was obtained.

[0075] (Alkylation of 2,2,4,7-tetramethyl-3,4-dihydro-1H-quinoline)

[0076] [ka]

[0077] Under nitrogen, a RB flask was charged with [4-(bromomethyl)phenyl]-triphenylsilane (13.8 g, 0.0321 mol), 2,2,4,7-tetramethyl-3,4-dihydro-1H-quinoline (6.08 g, 0.0321 mol), and 200 mL of DMF. The mixture was cooled to 0° C. and sodium hydride (60.0%, 1.41 g, 0.0353 mol) was added. The reaction was stirred under nitrogen and allowed to warm slowly to room temperature. At the 2 hour mark, the reaction was warm and homogeneous, but after approximately 15 minutes the product crashed out and stirring was stopped. The reaction became a solid white paste.

[0078] The reaction was triturated in water and filtered / washed with water. The organics were chromatographed eluting with hexane / ethyl acetate (5%). The appropriate fractions were combined and evaporated to give an off-white solid. This was dissolved in DCM, hexane was added and the DCM was evaporated off. The resulting solid was filtered.

[0079] Triphenyl-[4-[(2,2,4,7-tetramethyl-3,4-dihydroquinolin-1-yl)methyl]phenyl]silane (10.86 g, 0.0202 mol, 63.0% yield) was obtained.

[0080] (Vilsmeier-Haack formylation of triphenyl-[4-[(2,2,4,7-tetramethyl-3,4-dihydroquinolin-1-yl)methyl]phenyl]silane)

[0081] [ka]

[0082] Under nitrogen, a round bottom flask was charged with 200 mL of DCM, N,N-dimethylformamide (3.69 mL, 0.0479 mol), and POCl3 (4.04 mL, 0.0442 mol). After stirring the reaction for 1 h, quinoline (dissolved in an additional 200 mL of DCM) was added dropwise to the reaction using an addition funnel at a fast rate. The mixture was stirred at room temperature for 16 h and then further stirred at 32° C. for 24 h. The reaction mixture was cooled to room temperature, after which 10% sodium carbonate was added and stirred vigorously for 1 h. The phases were separated and the organic phase was dried over anhydrous MgSO4. This material was purified by elution through a silica gel column using DCM as the eluent. The appropriate fractions were combined and concentrated. The resulting material was triturated in hexane, filtered, and dried.

[0083] There was obtained 2,2,4,7-tetramethyl-1-[(4-triphenylsilylphenyl)methyl]-3,4-dihydroquinoline-6-carbaldehyde (18.9 g, 0.0334 mol, 90.7% yield) as a bluish white powder.

[0084] (Knoevenagel condensation)

[0085] [ka]

[0086] A round bottom flask was charged with 2,2,4,7-tetramethyl-1-[(4-triphenylsilylphenyl)methyl]-3,4-dihydroquinoline-6-carbaldehyde (1.00 g, 0.00177 mol), 2-[3-cyano-4-methyl-5-(4-phenylphenyl)-5-(trifluoromethyl)-2-furylidene]propanedinitrile (0.692 g, 0.00177 mol), 1-propanol (10.0 mL) and acetic acid (1.01 mL, 0.0177 mol). The reaction was sealed and stirred at 80° C. for 16 hours. The reaction mixture was turned off and evaporated. The residue was purified by normal phase chromatography (eluting with 15-30% EtOAc in hexanes). Appropriate fractions were combined and evaporated to give a colorful film. This was dissolved in DCM and evaporated to crystallize overnight.

[0087] There was obtained 2-[3-cyano-5-(4-phenylphenyl)-4-[(E)-2-[2,2,4,7-tetramethyl-1-[(4-triphenylsilylphenyl)methyl]-3,4-dihydroquinolin-6-yl]vinyl]-5-(trifluoromethyl)-2-furylidene]propanedinitrile (1.12 g, 0.00119 mol, 67.5% yield).

[0088] Example 2: Chromophore IV8422 (Buchwald coupling of 1,2,3,4-tetrahydroquinoline with 1-(5-bromo-2-methoxy-phenyl)adamantane)

[0089] [ka]

[0090] A solution of 1,2,3,4-tetrahydroquinoline (2.00 g, 0.0150 mol) and 1-(5-bromo-2-methoxy-phenyl)adamantane (97.0%, 5.22 g, 0.0158 mol) in toluene was sparged with N2 and then treated with potassium tert-butoxide (2.19 g, 0.0195 mol), Pd(OAc)2 (0.135 g, 0.000601 mol), and tri-tert-butylphosphine (0.243 g, 0.00120 mol). The flask was fitted with a condenser and the reaction mixture was heated to 115° C. overnight. The reaction mixture was concentrated and diluted with 1:1 DCM / hexanes. The solids were removed by vacuum filtration. The filtrate was concentrated and diluted with MeOH. A beige solid precipitated out of solution. The solid was isolated and soaked again in MeOH (2 times). The solid was isolated and dried by vacuum filtration, then soaked in Et2O (3 times). The solid was isolated and dried by vacuum filtration, then dried in air over the weekend.

[0091] There was obtained 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline (96.0%, 5.25 g, 0.0135 mol, 89.8% yield) as a brown solid.

[0092] (Vilsmeier-Haack formylation of 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline)

[0093] [ka]

[0094] A suspension of 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline (96.0%, 4.00 g, 0.0103 mol) and N,N-dimethylformamide (3.98 mL, 0.0514 mol) in DCM (50 mL) was sparged with N2, followed by the dropwise addition of POCl3 (3.76 mL, 0.0411 mol). The mixture was stirred at room temperature. The mixture immediately turned olive green and after 20 min it was dark amber. After 35 min, LCMS analysis indicated >99% conversion to the iminium and aldehyde. The reaction was quenched by pouring into 10% Na2CO3 ice solution. The mixture was diluted with DCM and stirred vigorously overnight. The DCM was evaporated leaving an aqueous with a large amount of precipitated solid. The solid was collected by vacuum filtration. LCMS analysis indicated complete hydrolysis to the aldehyde. The solid was triturated in Et2O (twice), isolated and dried under reduced pressure.

[0095] There was obtained 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline-6-carbaldehyde (98.0%, 4.45 g, 0.0109 mol, 106% yield) as a brown solid.

[0096] (Wittig condensation reaction of 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline-6-carbaldehyde with thiophenephosphonium bromide)

[0097] [ka]

[0098] A solution of triphenyl(2-thienylmethyl)phosphonium bromide (9.74 g, 0.0222 mol) in THF (250 mL) was treated with potassium tert-butoxide (2.49 g, 0.0222 mol). The mixture immediately turned red-orange. After 10 min, 1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinoline-6-carbaldehyde (4.45 g, 0.0111 mol) was added in small portions. The flask was capped and the reaction mixture was stirred at room temperature. LCMS analysis after 2 h showed complete conversion. The mixture was concentrated and the residue was dissolved in Et2O. The solids were removed by filtration and the filtrate was concentrated. This material was purified by normal phase chromatography (15% EtOAc in hexanes). The product fractions were concentrated.

[0099] There was obtained 1-[3-(1-adamantyl)-4-methoxy-phenyl]-6-[(E)-2-(2-thienyl)vinyl]-3,4-dihydro-2H-quinoline (87.0%, 5.01 g, 0.00906 mol, 81.7% yield) as a bright yellow film.

[0100] (Vilsmeier-Haack formylation of 1-[3-(1-adamantyl)-4-methoxy-phenyl]-6-[(E)-2-(2-thienyl)vinyl]-3,4-dihydro-2H-quinoline)

[0101] [ka]

[0102] A solution of 1-[3-(1-adamantyl)-4-methoxy-phenyl]-6-[(E)-2-(2-thienyl)vinyl]-3,4-dihydro-2H-quinoline (87.0%, 5.01 g, 0.00906 mol) and DMF (3.51 mL, 0.0453 mol) in DCM (250 mL) was sparged with N2, followed by the dropwise addition of POCl3 (1.04 mL, 0.0113 mol). The bright yellow mixture was stirred at room temperature overnight. The reaction was quenched by pouring into 10% Na2CO3 ice solution. The mixture was diluted with DCM and stirred vigorously for 96 h. The DCM was evaporated leaving an aqueous with a large amount of precipitated solid. The solid was collected by vacuum filtration. The solid was dissolved in Et2O and purified by NP chromatography (20% EtOAc in hexanes). The product fractions were concentrated.

[0103] There was obtained (Z)-3-[1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinolin-6-yl]-2-(2-thienyl)prop-2-enal (96.4%, 2.81 g, 0.00531 mol, 58.7% yield) as a bright orange solid.

[0104] (Knoevenagel condensation of (Z)-3-[1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinolin-6-yl]-2-(2-thienyl)prop-2-enal and 2-(3-cyano-4,5,5-trimethyl-2-furylidene)propanedinitrile)

[0105] [ka]

[0106] A suspension of (Z)-3-[1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinolin-6-yl]-2-(2-thienyl)prop-2-enal (96.4%, 1.00 g, 0.00189 mol) in EtOH (50 mL) was treated with 2-(3-cyano-4,5,5-trimethyl-2-furylidene)propanedinitrile (0.414 g, 0.00208 mol). The flask was sealed with a septum and the mixture was stirred at 60 °C for 120 h. It was then warmed to 95 °C for an additional 48 h. The reaction mixture was concentrated and purified by normal phase chromatography (50-100% DCM in hexanes). The product fractions were concentrated and the residue was recrystallized from DCM / MeOH.

[0107] 2-[4-[(1E,3Z)-4-[1-[3-(1-adamantyl)-4-methoxy-phenyl]-3,4-dihydro-2H-quinolin-6-yl]-3-(2-thienyl)buta-1,3-dienyl]-3-cyano-5,5-dimethyl-2-furylidene]propanedinitrile (0.472 g, 0.000683 mol, 36.1% yield) was obtained as a green powder.

[0108] Those skilled in the art will appreciate that changes can be made to the embodiments described above without departing from the broad inventive concept. It is understood, therefore, that the invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the invention as defined by the appended claims.

Claims

1. 1. A composition for preparing an electro-optic film exhibiting one or more optimized optical properties, said composition comprising: General formula (I) D-Pi-A (I) wherein D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D; and Π represents a Π-bridge between A and D; a polar solvent adapted to promote hyperpolarizability of said electro-optic film; Including, the Π-bridge comprises a carbon chain covalently linking and separating A and D, the carbon chain length between A and D being 2 to 4 carbon atoms, the 2 to 4 carbon atom chain comprising up to 2 carbon-carbon double bonds and up to 4 pendant substituents; The nonlinear optical chromophore has a λ of 800 nm or less. ｍａｘ indicates the value, The nonlinear optical chromophore has a Δλ of 30 nm or more compared to its analog in nonpolar solvents. ｍａｘ Show values A composition comprising:

2. The composition of claim 1 , wherein the one or more optimized optical properties are characterized by a high level of transparency at wavelengths longer than 800 nm.

3. 2. The composition of claim 1, wherein the one or more optimized optical properties is an electro-optic coefficient, the value of the electro-optic coefficient being 20 pm / V or greater when measured at a wavelength of 1000 nm or greater.

4. The composition of claim 1 , wherein the one or more optimized optical properties is a glass transition temperature of about 100° C. or greater.

5. The composition of claim 1 , wherein the one or more optimized optical properties is low optical loss, the optical loss being less than 2 dB / cm.

6. The composition of claim 1 , wherein the one or more optimized optical properties are characterized by high thermal stability characterized by a decomposition temperature greater than 250° C.

7. The composition of claim 1 , wherein the one or more optimized optical properties are characterized by high light stability as measured by degradation of an electro-optic film under broadband light and ambient conditions.

8. The nonlinear optical chromophore has the general formula (Ia) 【Chemistry 1】 wherein D represents an organic electron donating group; A represents an organic electron accepting group having an electron affinity greater than that of D; x is 1 or 2; and each R is independently hydrogen, an alkyl group, an aryl group, an alkyl or aryl group linked by sulfur or oxygen, an aryl group (optionally with a diamondoid group) linked directly by a carbon-carbon bond (e.g., adamantyl anisole), a halogen, a halogenated alkyl group, a halogenated aryl group, a branched or unbranched, optionally containing a heteroatom, a C alkyl group, a C aryl ... １ -C ４ 2. The composition of claim 1, comprising a nonlinear optical chromophore, which is a substituent, or a diamondoid-containing group.

9. 9. The nonlinear optical chromophore of claim 8, wherein the electron donating group comprises a substituted or unsubstituted quinolinyl group.

10. The electron donating group is 【Chemistry 2】 9. The nonlinear optical chromophore of claim 8, selected from the group consisting of:

11. 9. The nonlinear optical chromophore of claim 8, wherein at least one R group represents a thiophene.

12. 9. The nonlinear optical chromophore of claim 8, characterized in that x is 2 and at least one R group represents a thiophene.

13. 9. The nonlinear optical chromophore of claim 8, wherein x is 1 and each R represents hydrogen.

14. 10. The nonlinear optical chromophore of claim 9, characterized in that at least one R group represents a thiophene.

15. 10. The nonlinear optical chromophore of claim 9, characterized in that x is 2 and at least one R group represents a thiophene.

16. 10. The nonlinear optical chromophore of claim 9, wherein x is 1 and each R represents hydrogen.

17. The nonlinear optical chromophore has the general formula 【Chemistry 3】 2. The composition of claim 1, comprising a nonlinear optical chromophore having the formula:

18. The nonlinear optical chromophore has the general formula 【Chemistry 4】 2. The composition of claim 1, comprising a nonlinear optical chromophore having the formula:

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