Coumarin photobase generator for polyimide formation

Abstract

This disclosure relates to a photobase generator comprising a coumarin moiety, a visible light absorbing moiety, and a linker complex. In one embodiment, a base moiety for producing polyimide is provided by irradiating the photobase generator with visible light.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims the benefits of U.S. Provisional Patent Application No. 63 / 492,400, filed on 27 March 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] This disclosure relates to compounds used in photobase generators, which may, for example, be used in polyimide formation. [Background technology]

[0003] Photobase generators (PBGs) typically consist of three components: a chromophore, which absorbs light and converts photon energy into chemical energy; a latent base, which releases the actual base upon irradiation; and a linker, which connects the base and the chromophore. PBGs that release amine bases upon light irradiation are being studied in the fields of photoinitiated polymerization, photo-induced crosslinking of polymers, photopatterning, adhesives, and lithography. However, the development of photobase generators lags behind that of photoacid generators. PBGs exist in both nonionic and ionic forms. Various substances have been used as light-absorbing chromophores, most of which absorb light in the ultraviolet region. Representative PBG linkers include carbamates, O-acyloximes, ammonium salts, sulfonamides, formamides, nifedipine, and α-aminoketones. O-acyloximes require water to release the base. Therefore, water-sensitive polymer substrates may not be ideal. Generally speaking, carbamate linker-based PBGs are efficient and offer greater versatility in synthesis.

[0004] Due to their chemical, mechanical, and electrical properties, polyimides have been widely used as protective and insulating layers in microelectronics. Photosensitive polyimides (PSPIs) can be patterned by direct exposure and developed without photoresist, and are therefore sometimes used in microelectronics. PSPIs can be applied to a variety of electronic materials, electro-optical materials, waveguide materials, and nonlinear optical materials. Photosensitive polyimide systems typically contain a polyimide precursor and a photobase generator as an accelerator for forming polyimide by photoreaction. However, polyimide precursors, which have aromatic rings as their basic skeleton, generally have a broad absorption band in the ultraviolet (UV) region with wavelengths below 400 nm. Therefore, when irradiated with ultraviolet light, the polyimide precursor mainly absorbs the light, preventing the photochemical reaction from proceeding effectively in the exposed area, which can lead to decreased sensitivity and deterioration of the pattern shape. Thus, a photosensitive system containing a photobase generator that absorbs in the visible spectral region can be used to obtain a photosensitive polyimide with the desired photosensitivity and film properties.

[0005] However, a major challenge for most PBGs is that they exhibit little absorption above 400 nm, and base generation is triggered solely by ultraviolet light. Compared to visible light initiators, UV reaction catalysts require high photon energy, often resulting in reduced curing depth and potentially causing irreversible damage to UV-sensitive materials. Furthermore, existing photobase generators exhibit high thermal persistence and low base release efficiency through photodegradation, potentially reducing the efficiency of photosensitive polyimide-based electronic devices. Therefore, further contributions to this technology are needed, for example, photobase generators that exhibit absorption in the visible spectral region, base release under light irradiation, low thermal persistence, and low dielectric loss. [Overview of the project]

[0006] The photo-base generator compounds described in this specification may be used to improve the absorption of materials in the visible spectrum region, the base release efficiency by photodegradation, and the thermal residue. The photo-base generators of the present disclosure can achieve good absorption in the visible spectrum region, efficient release of bases under light irradiation, and low thermal residue. In some embodiments, the photo-base generator absorbs light of a first wavelength and emits light of a second wavelength higher than the first wavelength. As an example, the photo-base generators disclosed herein can be utilized in a method for manufacturing polyimide films used in microelectronics, printed circuit boards, and optical devices. The polyimide films manufactured according to the teachings of the present disclosure can exhibit high thermal and mechanical stability.

[0007] In some embodiments, the photo-base generator compound may include a coumarin derivative, a linker group, and a piperidine derivative. In some embodiments, the linker group may covalently link the coumarin derivative and the base moiety and may have a group responsible for efficient light emission of the piperidine derivative. In some embodiments, the coumarin derivative may absorb the light energy of the first excitation wavelength and transfer the energy to the linker group. In some embodiments, the linker group may release the base moiety by heterolytic cleavage. In some embodiments, the photo-base generator may include a compound having the following general formula.

[0008] [Chemical formula]

[0009] In this formula, R1 and R2 may be independently selected from hydrogen, a methyl group, an alkyl group and vinyl group having 1 to 4 carbon atoms, a dimethylvinyl group, an allyl group, a dimethylallyl group, an isopropyl group, a cyclopropyl group, and an aryl group. In some embodiments, R3 may be selected from hydrogen and / or an aryl group, such as a phenyl group. In some embodiments, R4 may be a base moiety. In some embodiments, R4 may be selected from piperidine, 4-methylpiperidine, 4-ethylpiperidine, and 2,6-dimethylpiperidine. [ka]

[0010] In some embodiments, R1 and / or R2 may be selected from hydrogen, a methyl group, an alkyl group having 1 to 4 carbon atoms, a vinyl group, a dimethylvinyl group, an allyl group, a dimethylallyl group, an isopropyl group, a cyclopropyl group, and an aryl group. In some embodiments, R1 or R2 may be selected from the following: [ka]

[0011] In some embodiments, the photobase generator has one of the following structures.

[0012] [ka]

[0013] [ka]

[0014] [ka]

[0015] [ka]

[0016] [ka]

[0017] [ka]

[0018] [ka]

[0019] [ka]

[0020] In some embodiments, a method for producing polyimide includes preparing a polyimide precursor dispersion in the photobase generator and dispersant described herein, coating a substrate with PBG and the polyimide precursor, irradiating the substrate coated with PBG and the polyimide precursor with visible light, and / or heating the coated substrate to remove the dispersant from the coating and / or cure the coated substrate. In some embodiments, the method may include selectively irradiating the substrate coated with the photobase generator and precursor with visible light while masking a portion of the coated substrate. In some embodiments, a method for measuring the base release efficiency of the photobase generator compound may include dissolving the photobase generator described herein in acetonitrile, measuring the pH of the photobase generator / acetonitrile solution, exposing the photobase generator / acetonitrile solution to visible light, and / or measuring the pH of the photobase generator / acetonitrile solution activated with visible light.

[0021] In one embodiment, the photobase-generating compound described herein may have excellent absorption in the visible spectral region, low thermal persistence when heated to temperatures up to 450°C, and / or separation of the base moiety. In another embodiment, a method for producing a polyimide film using the photobase-generating compound described herein is provided. These and other embodiments are described in further detail below. [Brief explanation of the drawing]

[0022] [Figure 1] Figure 1 shows the absorption spectra of examples of photobase generators described herein that exhibit absorption in the visible spectral region. [Figure 2] Figure 2 is a graph showing the weight of the photobase generator described herein as a function of heat (thermogravimetric analysis of an example of a photobase generator). [Modes for carrying out the invention]

[0023] For the purpose of facilitating understanding of this disclosure, the following embodiments will be described with reference and in specific terms. However, the scope of this disclosure is not limited thereto, and it will be understood that such changes and further modifications to the subject matter described herein, as well as such further applications of the disclosed principles as described herein, are intended to be those that are typically possible for those skilled in the art to which this disclosure relates.

[0024] This disclosure describes photobase-generating compounds and their use in the production of reactive precursors for polyimide production. The photobase-generating compounds may be used for the formation of polyimides under photoirradiation conditions, and may be useful for the efficient manufacture of microelectronic devices. In some embodiments, the photobase-generating compounds may absorb light in the visible region, for example, from 380 nm to 440 nm, may exhibit high photobase-releasing activity, and may have extremely low thermal persistence when heated above 400°C.

[0025] This disclosure also relates to a photobase-generating compound that absorbs light energy of a first wavelength and forms a carbamate containing a coumarin-methyl carbocation and a base moiety by heterolytic cleavage. The carbamate, which is the base and carbon dioxide moiety, can be further cleaved to provide a desired base compound. Furthermore, the cleaved base compound can act as a catalyst for forming polyimides from polyimide precursors.

[0026] As used herein, the terms “bond,” “bonded,” “direct bond,” or “single bond” refer to a chemical bond between two atoms or between two parts, where the atoms bonded by the bond are considered part of a larger structure.

[0027] As used herein, the term “part” refers to a specific location or functional group of a molecule. A chemical part is often perceived as a chemical entity that is embedded within or attached to a molecule.

[0028] As used herein, the term "coumarin" refers to a chemical moiety having the following structure: [ka]

[0029] As used herein, the terms "piperidine" or "piperidine derivative" refer to the chemical moiety having the following structure: [ka]

[0030] In some embodiments, the photobase-generating compound may comprise a coumarin derivative, a linker group, and a piperidine derivative. In one embodiment, the photobase-generating compound comprises a visible light-absorbing coumarin moiety, a linker moiety containing a functional group that can promote the efficient cleavage of a base, such as the base moiety, and a separable base moiety. In some embodiments, a phenyl group is substituted on the double bond of the coumarin moiety to extend conjugation and to efficiently release the base by suppressing the possibility of dimerization under photoirradiation conditions. In some embodiments, a cyclopropyl group, a phenyl group, a dimethylvinyl group, or a dimethyl group is bonded to the linker to efficiently release the base.

[0031] In some embodiments, the photobase generating compound comprises a coumarin derivative. In some embodiments, the photobase generating compound has the following general formula. [ka]

[0032] In this formula, R1 and R2 can be independently selected from hydrogen, a methyl group, an alkyl group having 1 to 4 carbon atoms, a vinyl group, a dimethylvinyl group, an allyl group, a dimethylallyl group, an isopropyl group, a cyclopropyl group, and an aryl group. In some embodiments, R1 or R2 can be selected from the following: [ka]

[0033] In some embodiments, R3 may be selected from hydrogen and / or an aryl group, such as a phenyl group. In some embodiments, R4 may be a base moiety. In some embodiments, the base moiety may be independently selected from piperidine, 4-methylpiperidine, 4-ethylpiperidine, and / or 2,6-dimethylpiperidine. In some embodiments, R4 may be selected from the following: [ka]

[0034] It is thought that the R1 or R2 group can promote the rapid release of the base by stabilizing the coumarin carbocation through the formation of secondary and tertiary carbocations, or through hyperconjugation.

[0035] In some embodiments, the photobase generators disclosed herein may be any of the following compounds, provided for illustrative purposes only and not to be construed as limiting:

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] In some embodiments, a method for measuring the base release efficiency of a photobase generator comprises dissolving the photobase generator compound disclosed herein in a polar solvent such as acetonitrile. In some embodiments, the method may also include measuring the pH of the photobase generator / acetonitrile solution. In some embodiments, the method involves measuring the pH of the photobase generator / acetonitrile solution at 600 mJ / cm³. 2 This may include exposure to visible light such as [specific type of light]. In some embodiments, the method may include exposing the photobase generator / acetonitrile solution to visible light, and then measuring the pH of the photobase generator / acetonitrile solution activated by visible light. By comparing the pH before and after exposure, the change in pH can indicate the amount of base released, and therefore the efficiency.

[0045] In one embodiment, the photobase-generating compound may have high photosensitivity or high quantum yield for releasing a base moiety when exposed to radiation of a desired wavelength. Photosensitivity is indicated by the change in pH before and after exposure. In some embodiments, the pH change may be greater than 0.2, 0.4, 0.8, 1.5, and / or 2.2. In many embodiments, the release quantum yield may be greater than 0.2, 0.3, 0.4, 0.5, 0.6, 0.4, 0.8, 0.9, 1.0, 1.5, and / or 2.2. The base release efficiency can be measured by dividing the pH of the photobase-generating solution after exposure to light of a certain energy by the pH of the same solution before light exposure, and corresponds to the release efficiency of the PBG moiety. In various embodiments, the PBG moiety may have an release efficiency greater than 2.2. In some embodiments, the base release efficiency may be greater than 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.25, 1.5, 2.0, and / or 2.2. The pH change in the solution can be measured using a mercury lamp, such as a UV curing conveyor equipped with a Dymax 5000-EC lamp.

[0046] In some embodiments, the photobase generators described herein may have an absorption maximum peak between wavelengths of about 370 nm and about 440 nm. In many embodiments, the absorption peak may be in the range of about 370 nm, 375 nm, 380 nm, 390 nm, 395 nm, 400 nm, 410 nm, 420 nm, 430 nm, 440 nm to about 410 nm, 420 nm, 430 nm, 440 nm, and / or any permutation of the above values, for example, 365 nm, 405 nm, and / or 436 nm.

[0047] In some embodiments, the photobase generator comprises a yellow light-absorbing coumarin derivative and a piperidine base derivative, the spatial distance between them being optimized via a linker complex to form a carbamate anion, and then photo-emitting the piperidine base.

[0048] In one embodiment, the photobase generator compound (PBGC) may comprise a yellow light-absorbing coumarin derivative, a linker complex, and a piperidine base moiety. The linker complex covalently links the visible light-absorbing coumarin derivative and the piperidine base moiety. In some embodiments, the coumarin derivative absorbs light energy at a first excitation wavelength and transfers energy to the linker complex, resulting in heterolytic cleavage to form a coumarin-methyl carbocation and a carbamate anion. In such embodiments, the carbamate, which is a piperidine derivative and ester-bonded, releases a desired piperidine base moiety via photodecarboxylation. In such embodiments, the pH change of the released base can be greater than 2.2. In such embodiments, the released base compound acts as a catalyst for forming polyimide from a polyimide precursor.

[0049] The linker complex covalently links a yellow light-absorbing coumarin derivative to the piperidine base moiety. The linker complex can be tuned to optimize the rapid release of the piperidine base moiety. By optimizing the linker complex, the efficiency of base release may be adjusted.

[0050] In many embodiments, the linker complex may contain stabilizing substitutions, such as dimethyl, methyl, dimethylvinyl, isopropyl, phenyl, or cyclopropyl. In many embodiments, the photobase generator comprises linker complex (L), which covalently links a coumarin derivative, which may be yellow light absorber, to the piperidine base moiety. In some embodiments, the linker complex may contain a carbonyl bond between the coumarin derivative and the piperidine base moiety.

[0051] In some embodiments, the linker complex may contain an unsubstituted ester group. When the linker complex contains an unsubstituted ester group, the linker complex may have one of the following structures. [ka]

[0052] In some embodiments, the linker complex may contain an unsubstituted ester or a substituted ester. In some embodiments, the linker complex may contain an ester group having 2 to 7 carbon atoms, which may be optically substituted. When the linker complex contains a substituted ester group, the linker complex may be selected from any of the following structures. [ka] A method for producing polyimide may include preparing a photobase generator and a polyimide precursor dispersion as described herein. In some embodiments, the PBG and polyimide precursor may be dispersed in a solvent and / or a dispersant. In some embodiments, the polyimide precursor may be a polyamic acid. In some embodiments, the dispersant may be an aprotic / polar / nonpolar solvent such as n-methylpyrrolidone (NMP). In some embodiments, the method is performed at about 600 mJ / cm 2The method may also include irradiating the substrate coated with PBG and polyimide precursor with visible light such as the above. In some embodiments, the method may include heating the coated substrate, for example, at about 120°C for at least 10 minutes, in order to remove the dispersant from the coating. In some embodiments, the method may also include heating the coated surface, for example at about 185°C for about 5 minutes, in order to cure, polymerize, and / or solidify the surface of the coated substrate. In some embodiments, the method may include masking a portion of the substrate coated with the dispersant in order to limit, minimize, or reduce the exposure of the precursor dispersant to visible light. [Examples]

[0053] The following examples are for illustrative purposes only and should not be construed as limiting the subject matter disclosed herein to the embodiments disclosed therein.

[0054] The photobase generators described herein have been found to exhibit absorption above 400 nm and improve photobase emission performance, as shown in the following examples. These examples are illustrative of the disclosure and are not intended to limit the scope or fundamental principles of the disclosure in any way.

[0055] The following example shows the synthesis procedure for a coumarin photobase generator. <Example 1: Synthesis of a photobase generator> [PBGC-1] 2-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)propan-2-yl(2R,6S)-2,6-dimethylpiperidine-1-carboxylate. [ka]

[0056] (Compound 1) Add 7-(diethylamino)-4-(2-hydroxypropan-2-yl)-2H-chromen-2-one to a 250 mL three-necked flask. 1 (4.96 g, 18.02 mmol) and 1,2-dichloroethane (90 mL) were added. N,N'-dimethylaminopyridine (4.18 g, 34.25 mmol) was added, and 4-nitrophenyl chloroformate (6.17 g, 30.64 mmol) was added at 0°C. After addition, the reaction mixture was stirred at room temperature for 14 hours. After completion, the reaction mixture was poured into H2O (200 mL), the extracted organic product was poured into CH2Cl2, washed with NaCl solution, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (5-10% ethyl acetate in CH2Cl2) to obtain the product. Yield: 5.30g, 70%. MS (LC / MS): Calculated value of chemical formula: C 23 H 25 N2O7[M+H] + =441; Measured value: 441. 1 H NMR(400MHz,CDCl3)δ8.26-8.12(m,2H),7.92(d,J=9.2Hz,1H),7.23-7.11(m,2H),6.60(dd,J=9.3,2.7 Hz,1H),6.55(d,J=2.7Hz,1H),6.11(s,1H),3.42(q,J=7.1Hz,4H),1.93(s,6H),1.22(t,J=7.1Hz,6H). [PBGC-1] (7-(diethylamino)-2-oxo-2H-chromen-4-yl)methyl(2R,6S)-2,6-dimethylpiperidine-1-carboxylate.

[0057] In a 100 mL three-necked flask, under an Ar atmosphere, 2-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)propan-2-yl (4-nitrophenyl) carbonate, Compound 1 (4.0 g, 9.43 mmol), hydroxybenzotriazole (0.38 g, 2.829 mmol), and N,N'-dimethylacetamide (110 mL) were added. 2,6-Dimethylpiperidine (5.10 mL, 37.73 mmol) was added, and the reaction mixture was stirred at 90 °C in the dark for 7 hours. After completion, the reaction mixture was poured into 1% aqueous NaHCO3 (200 mL), and the extracted organic product was poured into ethyl acetate, washed with NaCl solution, and dried over Na2SO4. After drying, the crude product was purified by flash chromatography (0 - 20% ethyl acetate in CH2Cl2) to obtain the product. Yield: 3.29 g, 70.2%. MS (LC / MS): Calculated for C 24 H 35 N2O4 [M + H] + = 415; Found: 415. 1 H NMR (400 MHz, CDCl3) δ 7.84 (d, J = 9.1 Hz, 1H), 6.58 - 6.42 (m, 2H), 6.07 (s, 1H), 4.31 (s, 2H), 3.39 (q, J = 7.1 Hz, 4H), 1.80 (s, 6H), 1.57 (q, J = 14.0 Hz, 4H), 1.46 (dq, J = 12.3, 3.6 Hz, 2H), 1.19 (t, J = 7.1 Hz, 12H). [PBGC-2] 1-(7-(Diethylamino)-2-oxo-2H-chromen-4-yl)-3-methylbut-2-en-1-ylpiperidine-1-carboxylate

Chemical Structure

[0058] In a 100 mL two-necked flask, 7-(diethylamino)-4-(1-hydroxy-3-methylbut-2-en-1-yl)-2H-chromen-2-one 2(1.0 g, 3.32 mmol) and carbonyldiimidazole (0.80 g, 4.98 mmol) were added to 23 mL of CH2Cl2. Triethylamine (0.80 mL, 5.64 mmol) was added dropwise, and the reaction mixture was stirred under reflux in the dark for 4 hours. Then, piperidine (0.98 mL, 9.96 mmol) was added, and the mixture was stirred in the dark for 12 hours. The reaction mixture was washed with water and NaCl solution, extracted with CH2Cl2, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (0-50% ethyl acetate in hexane) to obtain the product. Yield: 0.47g, 35%. MS (LC / MS): Calculated value of chemical formula: C 24 H 33 N2O4[M+H] + =413; Measured value: 413. 1 H NMR(400MHz,CDCl3)δ7.39(d,J=9.1Hz,1H),6.57(ddd,J=9.1,6.1,1.8Hz,2H),6.50(d,J=2.6Hz,1H),6.13(d,J=0.9Hz,1H ),5.32-5.20(m,2H),3.40(q,J=7.1Hz,8H),1.93(d,J=1.3Hz,2H),1.80(s,2H),1.71-1.42(m,8H),1.20(t,J=7.0Hz,6H). [PBGC-3] 1-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)-2-methylpropylpiperidine-1-carboxylate [ka] (Compound 3a) 7-(diethylamino)-4-(1-hydroxy-2-methylpropyl)-2H-chromen-2-one:

[0059] Under an argon atmosphere at -70°C, a solution of 7-(diethylamino)-2-oxo-2H-chromene-4-carbaldehyde (2.0 g, 8.16 mmol) was added slowly to a THF solution of isopropylmagnesium bromide (2 M, 8.16 mL, 16.32 mmol) in dried tetrahydrofuran (25 mL). The reaction mixture was stirred at -70°C for 2 hours. Then, saturated aqueous solution of NH4Cl was added, and the mixture was extracted with siRNA (twice). The combined organic layer was washed with saturated brine (once), dried on Na2SO4, and concentrated under reduced pressure. The product was purified by silica gel chromatography (10-15% ethyl acetate in CH2Cl2) to obtain a pale orange, fluffy solid. Yield: 1.3g (55.3%). MS (LC / MS): Calculated value of chemical formula: C 17 H 24 NO3 [M+H] + =289; Measured value: 289. 1 H NMR(400MHz,CDCl3)δ7.44(d,J=9.0Hz,1H),6.56(dd,J=9.0,2.7Hz,1H),6.52(d,J=2.6Hz,1H),6.19(d,J=1.0Hz,1H),4.73(d ,J=4.9Hz,1H),3.41(q,J=7.1Hz,4H),2.22-2.04(m,1H),1.21(t,J=7.1Hz,6H),1.06(d,J=6.9Hz,3H),0.96(d,J=6.7Hz,3H). (Compound 3b) 1-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)-2-methylpropyl(4-nitrophenyl)carbonate

[0060] 7-(diethylamino)-4-(1-hydroxy-2-methylpropyl)-2H-chromen-2-one, compound 3a (1.30 g, 4.50 mmol), and 1,2-dichloroethane (24 mL) were added to a 100 mL three-necked round-bottom flask. At room temperature, N,N'-dimethylaminopyridine (0.93 g, 7.64 mmol) was added. To this solution, 4-nitrophenyl chloroformate (1.36 g, 6.74 mmol) was added. After addition, the reaction mixture was stirred at room temperature for 14 hours. After completion, the reaction mixture was poured into H2O (200 mL), the extracted organic product was poured into CH2Cl2, washed with NaCl solution, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (5-10% ethyl acetate in CH2Cl2) to obtain the product. Yield: 1.62g (79.4%). MS (LC / MS): Calculated value of chemical formula: C 24 H 27 N2O7[M+H] + =454; Measured value: 454. 1 H NMR(400MHz,CDCl3)δ8.32-8.22(m,2H),7.44(d,J=9.1Hz,1H),7.41-7.30(m,2H),6.61(dd,J=9.1,2.6Hz,1H),6.52(d,J=2.6H) z,1H),6.16(d,J=0.7Hz,1H),5.70(d,J=5.9Hz,1H),3.42(q,J=7.1Hz,4H),1.21(t,J=7.1Hz,6H),1.09(dd,J=6.8,2.7Hz,6H). [PBGC-3] 1-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)-2-methylpropylpiperidine-1-carboxylate

[0061] 1-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)-2-methylpropyl(4-nitrophenyl)carbonate and compound 3b (1.60 g, 3.52 mmol) were added to a 50 mL two-necked round-bottom flask. Under Ar, 15 mL of 1,2-dichloroethane and piperidine (1.05 mL, 10.57 mmol) were added, and the reaction mixture was stirred in the dark for 1 hour. After completion, the reaction mixture was poured into H2O (100 mL), the extracted organic product was poured into CH2Cl2, washed with NaCl solution, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (5-20% ethyl acetate in CH2Cl2) to obtain the product. Yield: 0.9g, 65%. MS (LC / MS): Calculated value of chemical formula: C 23 H 33 N2O4[M+H] + =401; Measured value: 401. 1 H NMR(400MHz,CDCl3)δ7.45(d,J=9.0Hz,1H),6.58(dd,J=9.0,2.6Hz,1H),6.50(d,J=2.7Hz,1H),6.01(s,1H),5.76(d,J=5.0Hz,1H),3.54(s,2H) ),3.40(q,J=7.1Hz,6H),2.17(dq,J=13.2,6.7Hz,1H),1.71-1.47(m,8H),1.20(t,J=7.0Hz,7H),1.04(d,J=6.8Hz,3H),0.97(d,J=6.6Hz,3H). PBGC-4: (7-(diethylamino)-2-oxo-2H-chromen-4-yl)(phenyl)methylpiperidine-1-carboxylate [ka] (Compound 4a) 7-(diethylamino)-4-(hydroxy(phenyl)methyl)-2H-chromen-2-one:

[0062] In a 250 mL two-necked round-bottom flask, 7-(diethylamino)-2-oxo-2H-chromene-4-carbaldehyde (1.60 g, 6.53 mmol), phenylboronic acid (1.59 g, 13.06 mmol), tri-1-naphthylphosphine (0.14 g, 0.33 mmol), Pd(II)Cl2 (0.064 g, 0.33 mmol), and K2CO3 (1.84 g, 13.33 mmol) were added. Under Ar, 60 mL of tetrahydrofuran was added, and the reaction mixture was stirred under reflux for 1 hour. After completion, the reaction mixture was filtered through Celite and washed with CH2Cl2. After drying, the crude product was purified by flash chromatography (0-20% ethyl acetate in CH2Cl2) to obtain the product. Yield: 2.0g, 85%. MS (LC / MS): Calculated value of chemical formula: C 20 H 22 NO3 [M+H] + =324; Measured value: 324. 1 H NMR(400MHz,CDCl3)δ7.47-7.40(m,2H),7.40-7.29(m,3H),7.25(d,J=9.1Hz,2H),6.51-6.38(m ,3H),5.97(d,J=3.6Hz,1H),3.35(q,J=7.1Hz,4H),2.29(d,J=4.0Hz,1H),1.16(t,J=7.1Hz,6H). [PBGC-4]:

[0063] In a 50 mL two-necked flask, 7-(diethylamino)-4-(hydroxy(phenyl)methyl)-2H-chromen-2-one (1.0 g, 3.09 mmol), N,N'-dimethylaminopiperidine (0.38 g, 3.09 mmol), and carbonyldiimidazole (0.60 g, 3.71 mmol) were added to 15 mL of CH2Cl2. The reaction mixture was stirred under reflux in the dark for 3 hours. Then, piperidine (0.92 mL, 9.28 mmol) was added, and the mixture was stirred in the dark for 14 hours. The reaction mixture was washed with water and NaCl solution, extracted with CH2Cl2, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (0-5% ethyl acetate in CH2Cl2) to obtain the product. Yield: 0.74g, 55%. MS (LC / MS): Calculated value of chemical formula: C 26 H 31 N2O4[M+H] + =435; Measured value: 435. 1 H NMR(400MHz,CDCl3)δ7.47-7.41(m,2H),7.38-7.28(m,4H),7.01(d,J=1.0Hz,1H),6.47(d,J=1.1Hz,1H),6.45( d,J=2.6Hz,1H),6.26(d,J=1.0Hz,1H),3.46(s,4H),3.36(q,J=7.1Hz,4H),1.58(s,4H),1.16(t,J=7.1Hz,6H). [PBGC-5] 2-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)propan-2-ylpiperidine-1-carboxylate [ka]

[0064] 2-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)propan-2-yl(4-nitrophenyl)carbonate (compound 1 of PBGC-1 example) (1.24 g, 2.92 mmol) was placed in an oven-dried 50 mL two-necked flask. Under Ar, 20 mL of 1,2-dichloroethane and piperidine (0.87 mL, 8.773 mmol) were added, and the reaction mixture was stirred in the dark for 3 hours. After completion, volatile substances were removed under reduced pressure, and the crude product was purified by flash chromatography (0-20% ethyl acetate in CH2Cl2) to obtain the final product. Yield: 1.02g, 77.8%. MS (LC / MS): Calculated value of chemical formula: C 22 H 31 N2O4[M+H] + =387; Measured value: 387. 1H NMR(400MHz,CDCl3)δ7.82(d,J=8.9Hz,1H),6.51(d,J=2.7Hz,1H),6.48(d,J=2.8Hz,1H), 6.07(s,1H),3.39(q,J=7.1Hz,8H),1.80(s,6H),1.63-1.39(m,6H),1.19(t,J=7.1Hz,6H). [PBGC-6] 1-(7-(diethylamino)-2-oxo-2H-chromen-4-yl)ethylpiperidine-1-carboxylate [ka]

[0065] In a 100 mL two-necked flask, prepare 7-(diethylamino)-4-(1-hydroxyethyl)-2H-chromen-2-one. 1 (0.9 g, 3.43 mmol) and carbonyldiimidazole (0.67 g, 4.12 mmol) were added to 22 mL of CH2Cl2. Triethylamine (0.48 mL, 3.43 mmol) was added dropwise, and the reaction mixture was stirred under reflux in the dark for 4 hours. Then, piperidine (1.20 mL, 10.30 mmol) was added, and the mixture was stirred in the dark for 18 hours. The reaction mixture was washed with water and NaCl solution, extracted with CH2Cl2, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (0-20% ethyl acetate in CH2Cl2) to obtain the product. Yield: 0.78g (61%). MS (LC / MS): Calculated value of chemical formula: C 21 H 29 N2O4[M+H] + =373; Measured value: 373. 1 H NMR(400MHz,CDCl3)δ7.41(d,J=9.1Hz,1H),6.58(dd,J=9.1,2.6Hz,1H),6.51(d,J=2.6Hz,1H),6.10 (d,J=0.9Hz,1H),6.08-5.98(m,1H),3.41(q,J=7.1Hz,8H),1.71-1.48(m,9H),1.20(t,J=7.1Hz,6H). [PBGC-7] Cyclopropyl(7-(diethylamino)-2-oxo-2H-chromen-4-yl)methylpiperidine-1-carboxylate [ka] (Compound 7a) 4-(cyclopropyl(hydroxy)methyl)-7-(diethylamino)-2H-chromen-2-one:

[0066] Under an argon atmosphere at -70°C, a solution of 7-(diethylamino)-2-oxo-2H-chromene-4-carbaldehyde (1.5 g, 6.12 mmol) was added slowly to a THF solution of cyclopropylmagnesium bromide (1 M, 9.18 mL, 9.18 mmol). The reaction mixture was stirred at -70°C for 2 hours. Then, saturated aqueous solution of NH4Cl was added, and the mixture was extracted with siRNA (twice). The combined organic layer was washed with saturated brine (once), dried over Na2SO4, and concentrated under reduced pressure. The product was purified by silica gel chromatography (0-25% ethyl acetate in CH2Cl2) to obtain a fluffy solid. Yield: 1.0g, 57.1%. MS (LC / MS): Calculated value of chemical formula: C 17 H 22 NO3 [M+H] + =288; Measured value: 288. 1 H NMR(400MHz,CDCl3)δ7.62(d,J=9.0Hz,1H),6.58(dd,J=9.1,2.6Hz,1H),6.51(d,J=2.6Hz,1H),6.22(d,J=0.8Hz,1H),4.39(dd,J=7.6,3.7Hz ,1H),3.41(q,J=7.1Hz,4H),2.05(d,J=3.8Hz,1H),1.34(qt,J=8.0,5.0Hz,1H),1.21(t,J=7.1Hz,6H),0.74-0.58(m,2H),0.58-0.39(m,2H). (Compound 7b) Cyclopropyl(7-(diethylamino)-2-oxo-2H-chromen-4-yl)methyl(4-nitrophenyl)carbonate:

[0067] 4-(cyclopropyl(hydroxy)methyl)-7-(diethylamino)-2H-chromen-2-one, compound 7a (1.0 g, 3.48 mmol), and 1,2-dichloroethane (20 mL) were added to a 100 mL three-necked round-bottom flask. N,N'-dimethylaminopyridine (0.72 g, 5.92 mmol) was added at room temperature. 4-nitrophenyl chloroformate (1.05 g, 5.22 mmol) was added to this solution. After addition, the reaction mixture was stirred at room temperature for 14 hours. After completion, the reaction mixture was poured into H2O (200 mL), the extracted organic product was poured into CH2Cl2, washed with NaCl solution, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (5-8% ethyl acetate in CH2Cl2) to obtain the product. Yield: 1.04g, 66.2%. MS (LC / MS): Calculated value of chemical formula: C 24 H 25 N2O7[M+H] + =453; Measured value: 453. 1 H NMR(400MHz,CDCl3)δ8.32-8.23(m,2H),7.53(d,J=9.1Hz,1H),7.43-7.33(m,2H),6.63(dd,J=9.1,2.6Hz,1H),6.52(d,J=2.6Hz,1H),6.2 1(s,1H),5.40(d,J=8.5Hz,1H),3.43(q,J=7.1Hz,4H),2.06(s,1H),1.51(qt,J=8.2,4.9Hz,1H),1.23(q,J=6.7Hz,6H),0.90-0.47(m,4H). [PBGC-7]:

[0068] Cyclopropyl (7-(diethylamino)-2-oxo-2H-chromen-4-yl)methyl(4-nitrophenyl)carbonate and compound 6b (1.00 g, 2.21 mmol) were added to a 50 mL two-necked round-bottom flask. Under Ar, 15 mL of 1,2-dichloroethane and piperidine (0.65 mL, 6.63 mmol) were added, and the reaction mixture was stirred in the dark for 1 hour. After completion, the reaction mixture was poured into H2O (100 mL), the extracted organic product was poured into CH2Cl2, washed with NaCl solution, and dried on Na2SO4. After drying, the crude product was purified by flash chromatography (15-20% ethyl acetate in CH2Cl2) to obtain the product. Yield: 0.5g, 56.8%. MS (LC / MS): Calculated value of chemical formula: C 23 H 31 N2O4[M+H] + =399; Measured value: 399. 1 H NMR(400MHz,CDCl3)δ7.52(d,J=9.0Hz,1H),6.58(dd,J=8.9,2.6Hz,1H),6.51(d,J=2.6Hz,1H),6.11(s,1H),5.56(d,J=7 .5Hz,1H),3.75-3.19(m,8H),1.62-1.44(m,6H),1.33(dt,J=15.0,8.4Hz,1H),1.20(t,J=7.1Hz,6H),0.76-0.38(m,4H). <Example 2: Absorbance of Coumarin-based PBG>

[0069] The absorbance spectrum of the coumarin-based PBG in Example 1 was measured in N-methylpyrrolidone solvent using a Shimadzu UV3600 spectrometer. The normalized absorption spectrum of the coumarin-based PBG is shown in Figure 1. <Example 3: TGA data of coumarin-based PBG>

[0070] TGA measurements were performed using a TA Instruments TGA550 at a ramp rate of 10°C / min under a nitrogen atmosphere with a flow rate of 25 mL / min, from 25°C to 450°C. The TGA data for coumarin-based PBG in Example 1 are shown in Figure 2. <Example 4: Measurement of base release efficiency in solution>

[0071] Approximately 6 mg of the corresponding PBG compound was weighed into an amber-colored vial and dissolved in approximately 6 mL of acetonitrile. The initial pH (before exposure) was measured using a pH meter (Mettler Toledo S500-Std-K benchtop single-channel) (after three pH calibrations at pH 4.0, 7.0, and 10.0).

[0072] The base release efficiency indirectly obtained by pH change of the coumarin-based PBG sample in Example 1 was measured using a UV curing conveyor equipped with a Dymax 5000-EC lamp, at a solution concentration of ~600 mJ / cm³. 2 The measurement was performed by exposure to a mercury lamp. The results are shown in Table 1.

[0073] Furthermore, the results of the pH change of PBG during cauterization (before exposure, after exposure, and change Δ before and after exposure) are shown in Table 1 below. [Table 1] Polyimide formation

[0074] PBG and polyimide precursor polymer (polyamic acid) were weighed into containers / bottles (i.e., 30 mg of PBG in 3 g of PI varnish) and mixed using a Synkey stirrer (2000 rpm, 3 minutes, adding mixing time as needed until completely dissolved). Next, this mixed solution was spin-coated onto a stainless steel (JIS standard SUS304) substrate fixed to a hard glass plate with tape (main spin-coating speed: 1100 rpm, 30 seconds). Afterwards, it was fired at 120°C for 10 minutes to remove the N-methyl-2-pyrrolidone (NMP) solvent. Subsequently, 600 mJ / cm³ was applied. 2 Mercury lamp (Dymax / 225mW / cm²) 2The masked sample was exposed to a UV-curing conveyor (using a Dymax UV-curing conveyor, belt speed 13.5 fpm). Afterward, post-exposure baking was performed at 185°C for 5 minutes. As a final step, FT-IR measurements were performed on the unexposed (amide) / exposed (polyimide) regions to determine the polyimide formation rate (%) (polyimide formation rate % = corrected height of the imide peak (1777 cm)). -1 ) / Corrected height of benzene peak (1489cm) -1 ) × 100).

[0075] Unless otherwise specified, all numerical values ​​used in this specification and the claims to represent properties such as the amount of components and molecular weight, reaction conditions, etc., are understood to be modified in all cases by the term "approximately." Therefore, unless otherwise indicated, the numerical parameters described herein and in the appended claims are approximations that may vary depending on the desired properties to be obtained. At least, without the intention of limiting the application of the doctrine of equivalents to the claims, each numerical parameter should be interpreted using the usual rounding technique, taking into account at least the number of significant figures reported.

[0076] In the context describing this disclosure (in particular in the context of the following claims), the terms “a,” “an,” “the,” and similar demonstrative pronouns are to be interpreted as including both singular and plural unless otherwise indicated herein or unless the context clearly contradicts them. All methods described herein may be performed in any appropriate order unless otherwise indicated herein or unless the context clearly contradicts them. The use of any examples or representative expressions provided herein (e.g., “etc.”) is intended solely to better illustrate this disclosure and does not limit the scope of any claim. Nothing in this specification should be interpreted as indicating an unclaimed element essential to the practice of this disclosure.

[0077] The classification of alternative elements or embodiments disclosed herein shall not be construed as limiting. Elements of each group may be referenced and claimed individually or in any combination with other elements of that group or other elements found herein. For convenience and / or patentability reasons, it is expected that one or more elements of a given group may be included in or removed from a group.

[0078] Specific embodiments, including the best mode known to the inventors for carrying out this disclosure, are described herein. Of course, variations of these described embodiments will be obvious to those skilled in the art by reading the above description. The inventors anticipate that those skilled in the art will adopt such variations as appropriate, and they intend that this disclosure will be carried out in ways other than those specifically described herein. Accordingly, the claims include all modifications and equivalents of the subject matter described herein as permitted by applicable law. Furthermore, unless otherwise indicated herein, or unless it is clearly inconsistent with the context, the above elements are intended to be combined in any possible variations.

[0079] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the claims. Other modifications that may be adopted are included in the claims. Therefore, alternative embodiments may be used in accordance with the teachings herein, but not as examples. Thus, the claims are not strictly limited to the embodiments shown and described herein.

Claims

1. A photobase generator comprising a light-absorbing coumarin derivative, a linker group, and a base moiety, wherein the coumarin derivative and the base moiety are covalently linked by the linker group, light energy of a first excitation wavelength can be absorbed by the coumarin derivative and transferred to the linker group, and the base moiety can be released from the linker group by heterolytic cleavage.

2. The photobase generator according to claim 1, having a structure according to the following formula (I). 【Chemistry 1】 (I)

3. R 1 and R 2 These are independently selected from hydrogen, a methyl group, an alkyl group having 1 to 4 carbon atoms and a vinyl group, a dimethylvinyl group, an allyl group, a dimethylallyl group, an isopropyl group, a cyclopropyl group, and an aryl group. R 3 is hydrogen or a phenyl group, R 4 The photobase generator according to claim 2, wherein is selected from piperidine, 4-methylpiperidine, 4-ethylpiperidine, and 2,6-dimethylpiperidine.

4. R 1 and R 2 The photobase generator according to claim 2, wherein is independently selected from the following. 【Chemistry 2】

5. The photobase generator according to claim 1, having any of the following structures. 【Transformation 3】

6. The photobase generator according to claim 1, wherein the coumarin derivative has an absorption maximum peak at a wavelength of about 370 nm to about 440 nm.

7. The photobase generator according to claim 1, wherein the base portion is selected from piperidine, 4-methylpiperidine, 4-ethylpiperidine, and 2,6-dimethylpiperidine.

8. A compound according to the following formula (I), 【Chemistry 4】 (I) During the ceremony, R 1 and R 2 These are independently selected from hydrogen, a methyl group, an alkyl group having 1 to 4 carbon atoms and a vinyl group, a dimethylvinyl group, an allyl group, a dimethylallyl group, an isopropyl group, a cyclopropyl group, and an aryl group. R 3 is a hydrogen or phenyl group, R 4 The compound is selected from piperidine, 4-methylpiperidine, 4-ethylpiperidine, and 2,6-dimethylpiperidine.

9. R 1 and R 2 The compound according to claim 8, which is independently selected from the following: 【Transformation 5】

10. The compound according to claim 8, having any of the following structures. 【Transformation 6】

11. The compound according to claim 8, having an absorption maximum peak at a wavelength of approximately 370 nm to approximately 440 nm.

12. The process involves preparing a photobase generator according to claim 1 or a compound according to claim 8, and a polyimide precursor dispersion in a dispersant or solvent. The substrate is coated with the aforementioned dispersant, A method comprising irradiating the coated substrate with visible light.

13. The method according to claim 12, further comprising heating the coated substrate to remove the dispersant or curing the coated substrate.

14. The method according to claim 12, further comprising selectively irradiating the photobase generator and the substrate with visible light while masking a portion of the substrate.

15. The method according to claim 12, wherein the polyimide precursor is a polyamic acid.

16. The method according to claim 12, wherein the dispersant is an aprotic, polar, or nonpolar solvent.

17. The method according to claim 16, wherein the dispersant is n-methylpyrrolidone (NMP).

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