NAPHTHOPYRAN PHOTOSWITCHABLE PHOTOINITIATORS FOR LOCALLY POLYMERIZING A STARTING MATERIAL BY DUAL COLOR PHOTOPOLYMERIZATION

20250179306 ยท 2025-06-05

    Inventors

    Cpc classification

    International classification

    Abstract

    The present invention relates to a process for locally polymerizing a starting material by dual color photopolymerization using photoinitiator molecule which is represented by one of the following formula (Ib)

    ##STR00001##

    Claims

    1. A process for locally polymerizing a starting material by dual color photopolymerization, comprising: providing a polymerizable starting material containing photoinitiator molecules which can be converted by sequential optical excitation into a reactive state in which the photoinitiator molecules locally trigger polymerization of the starting material; and photopolymerizing the starting material in a local volume by irradiating light of a first wavelength and light of a second wavelength, different from the first wavelength, into the local volume, whereby in the local volume the photoinitiator molecules are converted, due to the absorption of the light of the first wavelength, from an initial state in which the photoinitiator molecules substantially do not absorb the light of the second wavelength, into an intermediate state with changed optical properties compared to the initial state, such that the photoinitiator molecules in the intermediate state absorb the light of the second wavelength; and the photoinitiator molecules are transferred from the intermediate state to the reactive state due to the absorption of the light of the second wavelength, which triggers the polymerization locally; wherein the photoinitiator molecule is represented by one of the following formula (Ib) ##STR00062## wherein R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.20 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl, substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; and the following structures (i) to (viii) ##STR00063## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    2. The process according to claim 1, wherein R.sup.1 and R.sup.2 are H or D; and at least one of R.sup.4 to R.sup.9, and R.sup.11 to R.sup.20 are independently selected from the group consisting of halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl, substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; and the following structures (i) to (viii) ##STR00064## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36 are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    3. The process according to claim 1, wherein At least one of R.sup.5, R.sup.6, R.sup.8, R.sup.13, and R.sup.18 is independently selected from the group consisting of halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl, substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; and the following structures (i) to (viii) ##STR00065## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.5, R.sup.6, R.sup.8, R.sup.13, R.sup.18 and R.sup.21 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.21-R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    4. The process according to claim 1, wherein R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.20 are independently selected from the group consisting of H; D; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, two R may form a ring structure; and the following structures (i) or (iii) ##STR00066## wherein R.sup.21 to R.sup.23 and R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.23 and R.sup.26, are independently selected from the group consisting of D; halogen; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; and substituted or unsubstituted C.sub.2-C.sub.49-aryl ester; and two adjacent groups of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.23 and R.sup.26 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.1 to R.sup.23, are independently selected from the group consisting of D; halogen; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; and substituted or unsubstituted C.sub.2-C.sub.49-aryl ester.

    5. The process according to claim 1, wherein R.sup.8 and R.sup.9 are linked to each other to form a substituted or unsubstituted fused ring structure.

    6. The process according to claim 1, wherein R.sup.6 and R.sup.7 are linked to each other to form a substituted or unsubstituted fused ring structure.

    7. The process according to claim 1, wherein at least one of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.20 is selected from the following structures (i) to (viii) ##STR00067## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.21-R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    8. The process according claim 1, wherein at least one of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.20 is selected from the following structures (i) and (iii) ##STR00068## wherein R.sup.21 to R.sup.23 and R.sup.26 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.23 and R.sup.26, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.21 to R.sup.23 and R.sup.26 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.23 and R.sup.26, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    9. The process according to claim 8, wherein at least one of R.sup.5, R.sup.6 and R.sup.8 is selected from the following structures (i) and (iii) ##STR00069## wherein R.sup.21 to R.sup.23 and R.sup.26 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.23 and R.sup.26, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.21 to R.sup.23 and R.sup.26 may be linked to each other to form a substituted or unsubstituted fused ring, wherein the one or more substituents, if present in one or more of R.sup.21 to R.sup.23 and R.sup.26, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    10. The process according to claim 1, wherein at least one of R.sup.1 to R.sup.20 is independently selected from the group consisting of ##STR00070## or an electron withdrawing group.

    11. The process according to claim 1, wherein one of R.sup.1 to R.sup.20 is independently selected from the group consisting of ##STR00071## or an electron withdrawing group.

    12. The process according to claim 1, wherein at least one of R.sup.5, R.sup.6, and R.sup.8 is independently selected from the group consisting of ##STR00072## or an electron withdrawing group.

    13. The process according to claim 1, wherein at least one of R.sup.5, R.sup.6 and R.sup.8 is ##STR00073##

    14. The process according to claim 1, wherein R.sup.1 to R.sup.20 are each H.

    15. The process according to claim 1, wherein the photoinitiator molecule has the formula PM-1 to PM-6 ##STR00074## ##STR00075##

    17. A process comprising using a photoinitiator molecule for locally polymerizing a starting material by dual color photopolymerization; wherein the photoinitiator molecule is represented by one of the following formula (Ib) ##STR00076## wherein R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 R.sup.20 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl, substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; and the following structures (i) to (viii) ##STR00077## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    18. An apparatus for locally polymerizing a starting material by dual color photopolymerization, comprising: an intake for a polymerizable starting material; light generating means arranged to generate light of a first wavelength and light of a second wavelength, the second wavelength being different from the first wavelength; and a light guide device arranged to irradiate the light of the first wavelength and the light of the second wavelength into a local volume; said device being adapted to perform the following procedure: taking up the polymerizable starting material by said intake, said starting material containing photoinitiator molecules which can be excited by sequential optical excitation into a reactive state in which the photoinitiator molecules locally initiate polymerization of the starting material; and photopolymerizing the starting material in a local volume by irradiating the light of the first wavelength and the light of the second wavelength into the local volume, whereby in the local volume the photoinitiator molecules, due to the absorption of the light of the first wavelength, are converted from an initial state in which the photoinitiator molecules substantially do not absorb the light of the second wavelength into an intermediate state with changed optical properties compared to the initial state, such that the photoinitiator molecules in the intermediate state absorb the light of the second wavelength; and the photoinitiator molecules are transferred from the intermediate state to the reactive state due to the absorption of the light of the second wavelength, which triggers the polymerization locally, wherein the photoinitiator molecule is represented by one of the following formula (Ib) ##STR00078## wherein R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 R.sup.20 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl, substituted or unsubstituted C.sub.1-C.sub.20-hetero alkyl, and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl, substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; and the following structures (i) to (viii) ##STR00079## wherein R.sup.21 to R.sup.36 are independently selected from the group consisting of H; D; halogen; NO.sub.2; CN; OH; SH; substituted or unsubstituted C.sub.1-C.sub.20-alkyl; substituted or unsubstituted C.sub.3-C.sub.20-cycloalkyl; substituted or unsubstituted C.sub.6-C.sub.48-aryl; substituted or unsubstituted C.sub.2-C.sub.42-heteroaryl; substituted or unsubstituted C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy, and NH.sub.2; substituted or unsubstituted C.sub.1-C.sub.20-alkyl ester; substituted or unsubstituted C.sub.6-C.sub.48-aryl ester; substituted or unsubstituted C.sub.1-C.sub.20 alkyl amide; substituted or unsubstituted C.sub.6-C.sub.48-aryl amide; NR.sub.2, SiR.sub.3, OSiR.sub.3 wherein R is independently selected from the group consisting of substituted or unsubstituted C.sub.1-C.sub.20-alkyl and substituted or unsubstituted C.sub.6-C.sub.48-aryl, two R may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof, substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C.sub.2-C.sub.20-alkynyl and substituted or unsubstituted C.sub.2-C.sub.20-alkenyl; or R.sup.15 and R.sup.16 form together a single bond and the remaining R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.14 and R.sup.17 to R.sup.36 are selected as defined above; wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH; and two adjacent groups of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36 may be linked to each other to form a substituted or unsubstituted fused ring structure, wherein the one or more substituents, if present in one or more of R.sup.1, R.sup.2, R.sup.4 to R.sup.9, and R.sup.11 to R.sup.36, are independently selected from the group consisting of D; halogen; NO.sub.2; CN, C.sub.2-C.sub.49-alkyl acyl; substituted or unsubstituted C.sub.1-C.sub.20-alkoxy; substituted or unsubstituted C.sub.6-C.sub.48-aryloxy; substituted or unsubstituted C.sub.2-C.sub.49-aryl acyl; substituted or unsubstituted C.sub.2-C.sub.49-aryl ester, (meth)acrylate; tosyl; NH.sub.2; and OH.

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0283] In the following, further design examples are explained with reference to figures in a drawing, wherein

    [0284] FIG. 1 shows a back reaction from B to A that can be triggered thermally or by radiation.

    [0285] FIG. 2 shows an example of producing a photoinitiator molecule and its necessary function.

    [0286] FIG. 3 shows a schematic representation of an embodiment of the process according to the invention;

    [0287] FIG. 4 shows a schematic representation of the process according to the invention; and

    [0288] FIG. 5 shows a perspective view of the embodiment of the inventive step shown in FIG. 4.

    [0289] FIG. 6 shows UV/Vis spectra of the objects printed by using comparative compound C-1 and the compounds PM-1, PM-3, PM-4 and PM-5 according to the present disclosure.

    [0290] FIG. 7 is a schematic view of a device for processing an optically reactive material from above.

    [0291] FIG. 8 is a schematic view of the device of FIG. 7 from the side.

    [0292] FIG. 9 shows another example of producing a photoinitiator molecule and its necessary function.

    DETAILED DESCRIPTION

    [0293] FIG. 3 schematically shows an embodiment of the invention. By means of a first light source 10 a light with a first wavelength is generated and irradiated onto a structure comprising a curable composition 14. The assembly is a layered assembly comprising a light-blocking layer 11 and two transparent layers 12. The assembly further comprises a spacer 13.

    [0294] In the space formed by the two transparent layers 12 and the spacer 13, the curable composition 14 corresponding to the polymerizable starting material and containing one or more photoinitiator molecules according to the invention is introduced. The layered structure further comprises two light-blocking layers 11 arranged so that at least a portion of the curable composition 14 can be irradiated by both the light of the first wavelength generated by the first light source 10 and a light of a second wavelength generated by the second light source 15. The region of the curable composition 14 which can be irradiated both by light from the first light source 10 and by light from the second light source 15 is cured according to the mechanism described herein.

    [0295] FIGS. 4 and 5 show a further embodiment of the invention in which a part of a curable composition 24, 34, is cured, which is simultaneously irradiated both by light from a first light source 20, 30 and light from a second light source 25, 35 through holes 23, 33 in light-blocking layers 21, 31 which partially shield the curable composition 24, 34 from the respective light sources 20, 30 and 25, 35, respectively. The curable composition 24, 34 is here arranged in a transparent container 22, 32. In this version it is provided that the light source 20, 30 is arranged orthogonally with respect to the second light source 25, 35. In principle, however, other angles are also provided here according to the invention.

    [0296] FIGS. 7 and 8 show a schematic representation of an arrangement for a device for optical processing of an optically reactive material from above and from the side. A working volume is provided in a receiving container 51, 61, which is at least partially filled by a starting material. The starting material can comprise one or more substances, which can be solid, liquid or pasty. For processing, the starting material is irradiated with light of a first wavelength from a first light generator 52, 62 and optionally light of a first wavelength from a second light generator 53, which are irradiated in an overlapping manner in the working volume to trigger an optically activated reaction in a layer subvolume 54. The receiving container 51, 61, which is at least partially filled by a starting material may be moved along an axis for cuvette moving 55, 65 to shift the position of the subvolume 54 in the receiving container 51, 61 and in the starting material filled therein.

    [0297] Alternatively, the first light generator 52, 62 and optionally the second light generator 53 may be moved along an axis to shift the position of the subvolume 54 in the receiving container 51, 61 and in the starting material filled therein (not shown in FIGS. 7 and 8).

    [0298] The first light generator 52, 62 and optionally the second light generator 53 may be a light sheet generator.

    [0299] Depending on the current position of the irradiation area 56, 66 (light sheet), the light of the second wavelength is projected with the aid of a projector 57, 67 into the layered part volume currently irradiated with the light of the first wavelength (projector or projection image). This means that the projection plane or projection volume of the projector 57, 67 is located in the layer subvolume that is currently being irradiated with the light of the first wavelength. The light of the first wavelength (light section) and the light of the second wavelength (light projection) thus at least partially overlap spatially or in a projection plane of the projector 57, 67 in a macroscopic partial layer volume of the starting material, which as a partial volume of the working volume which is just being irradiated by means of the light section.

    [0300] In this way, at least one material property of the starting material is changed in the currently irradiated layered partial volume, for example to the effect that the original starting material hardens. In this case, polymerization can be triggered in the starting material due to the coincidence of the light of the two wavelengths. In this way, it is possible, for example, to continuously produce a three-dimensionally shaped body layer by layer in the working volume. The three-dimensional shaping of the body is influenced and determined with the aid of the projection of the projector 57, 67 formed in the respective layer volume.

    [0301] In one embodiment, a process for local polymerization of a polymerizable starting material by means of dual color polymerization is provided. In dual color polymerization, photoinitiator molecules, which can also be designated as mediator molecules, absorb photons of light of different wavelengths in order to convert the photoinitiator molecules from the initial state via an intermediate state into a reactive state which is suitable for locally initiating or initiating a polymerization reaction in the polymerizable starting material so that the starting material is polymerized, up to hardening or curing, in particular in the case of plastics.

    [0302] The mediator molecule, in the following also called photoinitiator molecule, and its necessary function can be produced in different ways. One example is as shown in FIG. 9.

    [0303] The photoinitiator can exist in three different states, which are characterized as follows:

    Initial State (A):

    [0304] Without light irradiation the photoinitiator molecules are present in this state.

    Intermediate State (B):

    [0305] The B state is an electronic ground state. [0306] The intermediate state is created from the initial state A by absorption of light of wavelength .sub.1. [0307] The photoinitiator molecules have a new or more intense absorption band for light of wavelength .sub.2. [0308] Alternatively, the absorption band for 1 disappears. The photoinitiator molecule returns to the initial state A spontaneously in the absence of light or by absorption of light of wavelength .sub.3.

    Reactive State (C):

    [0309] The reactive state is generated from the intermediate state B by absorption of light of wavelength .sub.2. [0310] The reactive state initiates a polymerization reaction in the immediate vicinity of the molecule. [0311] A back reaction to B is not intended.

    EXAMPLES

    [0312] Hereinafter, the action and effect of the invention will be described in detail through specific examples of the invention. However, the examples are provided only to illustrate the present invention, and the scope of the invention is not limited thereto.

    Synthesis

    Synthesis of Compound PM-1

    ##STR00053##

    [0313] 1,1-Diphenyl-2-propyn-1-ol (1 g, 4.8 mmol) and 6-Benzoyl-2-naphthol (1.2 g, 4.8 mmol) are suspended in toluene (15 mL) and heated to 60 C. p-Toluenesulfonic acid (14 mg, 0.07 mmol) is added, and the mixture is stirred at 60 C. for 2 h. After cooling to room temperature ethyl acetate is added and the organic phase is washed with aqueous sodium hydroxide solution (1 M), water, and saturated aqueous sodium chloride solution. The remaining organic phase is dried over anhydrous magnesium sulfate and the solvents are removed under reduced pressure. The crude product is purified by silica gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield compound PM-1 as a solid (1.57 g, 90%).

    [0314] .sup.1H NMR (500 MHz, Methylene Chloride-d2) 8.16 (d, J=1.8 Hz, 1H), 8.08 (d, J=8.8 Hz, 1H), 7.95 (dd, J=8.8, 1.8 Hz, 1H), 7.84-7.79 (m, 2H), 7.77 (d, J=8.8 Hz, 1H), 7.65-7.60 (m, 1H), 7.55-7.49 (m, 6H), 7.41-7.32 (m, 5H), 7.31-7.26 (m, 3H), 6.39 (d, J=10.0 Hz, 1H).

    PM-2

    PM-2 (CAS 4222-20-2) is commercially available

    ##STR00054##

    Synthesis of Compound PM-3

    ##STR00055##

    [0315] 9-Ethynyl-9H-fluoren-9-ol (415 mg, 2.0 mmol) and 6-Benzoyl-2-naphthol (0.5 g, 2.0 mmol) are suspended in toluene (10 mL) and heated to 60 C. p-Toluenesulfonic acid (6 mg, 0.03 mmol) is added, and the mixture is stirred at 60 C. for 2 h. After cooling to room temperature ethyl acetate is added and the organic phase is washed with aqueous sodium hydroxide solution (1 M), water, and saturated aqueous sodium chloride solution. The remaining organic phase is dried over anhydrous magnesium sulfate and the solvents are removed under reduced pressure. The crude product is purified by silica gel column chromatography using petroleum ether/ethyl acetate mixtures as eluent to yield compound PM-3 as a solid (1.57 g, 90%).

    [0316] .sup.1H NMR (500 MHz, Methylene Chloride-d2) 8.26-8.18 (m, 2H), 8.02 (dd, J=8.8, 1.8 Hz, 1H), 7.88-7.84 (m, 2H), 7.77 (d, J=8.8 Hz, 1H), 7.71 (dt, J=7.6, 0.9 Hz, 2H), 7.64 (ddt, J=8.0, 6.9, 1.3 Hz, 1H), 7.57-7.50 (m, 5H), 7.45 (td, J=7.5, 1.1 Hz, 2H), 7.27 (td, J=7.5, 1.1 Hz, 2H), 7.08 (dd, J=8.8, 0.7 Hz, 1H), 5.77 (d, J=10.1 Hz, 1H).

    Synthesis of PM-4

    ##STR00056##

    [0317] 1,1-Diphenyl-2-propyn-1-ol (0.93 g, 4.5 mmol) and 4-Bromo-2-naphthol (1 g, 4.5 mmol) are suspended in toluene (20 mL) and heated to 55 C. p-Toluenesulfonic acid (13 mg, 0.067 mmol) is added, and the mixture is stirred at 55 C. for 2 h. After cooling to room temperature ethyl acetate is added and the organic phase is washed with aqueous sodium hydroxide solution (1 M), water, and saturated aqueous sodium chloride solution. The remaining organic phase is dried over anhydrous magnesium sulfate and the solvents are removed under reduced pressure. The crude product is purified by silica gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the halogenated naphthopyran as a white solid (1.36 g, 73%).

    [0318] .sup.1H NMR (500 MHz, Chloroform-d) 8.19-8.12 (m, 1H), 8.02-7.95 (m, 1H), 7.59 (d, J=0.7 Hz, 1H), 7.53 (ddd, J=8.4, 6.8, 1.3 Hz, 1H), 7.51-7.47 (m, 4H), 7.44 (ddd, J=8.2, 6.8, 1.2 Hz, 1H), 7.38-7.31 (m, 4H), 7.31-7.27 (m, 3H), 6.31 (d, J=10.0 Hz, 1H).

    [0319] The halogenated naphthopyran (0.5 g, 1.2 mmol) is dissolved in dry tetrahydrofuran (8 mL) under an argon atmosphere and cooled to 78 C. n-Butyl lithium (1.3 mmol, 2.5 M in hexanes) is added dropwise. After stirring for 30 min at 78 C., N-Methoxy-N-methylbenzamide (0.2 g, 1.3 mmol) is added, and the reaction mixture is allowed to warm to room temperature. The reaction is stirred for 3 h at room temperature and 1 M aqueous hydrochloric (10 mL) acid is added. The mixture is stirred for 20 min, 1 M aqueous NaOH solution is added (20 mL) and the mixture is extracted with ethyl acetate. The combined organic layers are dried over anhydrous MgSO.sub.4 and evaporated under reduced pressure. The residue is purified by silica-gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the compound PM-4 as a solid (0.39 g, 73%).

    [0320] .sup.1H NMR (500 MHz, Chloroform-d) 7.94 (dt, J=8.6, 0.9 Hz, 1H), 7.87 (dt, J=8.5, 0.9 Hz, 1H), 7.78-7.71 (m, 2H), 7.49 (ddt, J=8.7, 7.2, 1.3 Hz, 1H), 7.40 (ddd, J=8.4, 6.8, 1.3 Hz, 1H), 7.38-7.32 (m, 6H), 7.30-7.26 (m, 1H), 7.25-7.19 (m, 6H), 7.18-7.14 (m, 2H), 6.30 (d, J=10.0 Hz, 1H).

    Synthesis of PM-5

    ##STR00057##

    1,1-Diphenyl-2-propyn-1-ol (1.2 g, 5.8 mmol) and 4-Bromo-2-naphthol (1.3 g, 5.8 mmol) are suspended in toluene (20 mL) and heated to 55 C. p-Toluenesulfonic acid (16 mg, 0.09 mmol) is added, and the mixture is stirred at 55 C. for 1 h. After cooling to room temperature ethyl acetate is added and the organic phase is washed with aqueous sodium hydroxide solution (1 M), water, and saturated aqueous sodium chloride solution. The remaining organic phase is dried over anhydrous magnesium sulfate and the solvents are removed under reduced pressure. The crude product is purified by silica gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the halogenated naphthopyran as a white solid (2.2 g, 92%).

    [0321] .sup.1H NMR (500 MHz, Chloroform-d) 8.10 (d, J=1.8 Hz, 1H), 7.61 (d, J=8.8 Hz, 1H), 7.56 (d, J=8.7 Hz, 1H), 7.49 (t, J=1.8 Hz, 2H), 7.48 (dd, J=1.9, 0.8 Hz, 2H), 7.38 (dd, J=8.7, 1.9 Hz, 1H), 7.35-7.31 (m, 4H), 7.29-7.25 (m, 2H), 7.24-7.19 (m, 2H), 6.29 (d, J=10.0 Hz, 1H).

    [0322] The halogenated naphthopyran (1.1 g, 2.7 mmol) is dissolved in dry tetrahydrofuran (20 mL) under an argon atmosphere and cooled to 78 C. n-Butyl lithium (2.9 mmol, 2.5 M in hexanes) is added dropwise. After stirring for 30 min at 78 C., N-Methoxy-N-methylbenzamide (0.44 g, 2.9 mmol) is added and the mixture is stirred for 30 min at 78 C. The reaction mixture is allowed to warm to room temperature. The reaction is stirred for 1 h at room temperature and 1 M aqueous hydrochloric (10 mL) acid is added. The mixture is stirred for 20 min, 1 M aqueous NaOH solution is added (20 mL) and the mixture is extracted with ethyl acetate. The combined organic layers are dried over anhydrous MgSO.sub.4 and evaporated under reduced pressure. The residue is purified by silica-gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the compound PM-5 as a solid (0.73 g, 63%).

    [0323] .sup.1H NMR (500 MHz, Chloroform-d) 8.44-8.40 (m, 1H), 7.88-7.83 (m, 2H), 7.80 (d, J=8.4 Hz, 1H), 7.72 (dd, J=8.5, 1.7 Hz, 2H), 7.65-7.60 (m, 1H), 7.52 (dd, J=8.3, 7.0 Hz, 2H), 7.49-7.46 (m, 4H), 7.35-7.30 (m, 5H), 7.26 (ddt, J=7.2, 6.2, 1.3 Hz, 3H), 6.29 (d, J=10.0 Hz, 1H).

    Synthesis of PM-6

    ##STR00058##

    [0324] 4-Bromobenzen (10.0 g, 38.5 mmol) is dissolved in dry tetrahydrofuran (100 mL) and cooled to 0 C. Lithium acetylide ethylenediamine complex (20.8 g 192.5 mmol) is added and the mixture is stirred for 3 days. 1 M aqueous hydrochloric (150 mL) acid is added and the mixture is extracted with ethyl acetate. The combined organic layers are dried over anhydrous MgSO.sub.4 and evaporated under reduced pressure. The residue is purified by silica-gel column chromatography using petroleum ether/ethyl acetate (20/1) as eluent to yield 1-(p-Bromophenyl)-1-phenyl-2-propyn-1-ol (7.1 g, 60%).

    [0325] .sup.1H NMR (500 MHz, Chloroform-d) 7.61-7.57 (m, 2H), 7.50-7.44 (m, 4H), 7.37-7.32 (m, 2H), 7.32-7.27 (m, 1H), 2.94 (s, 1H), 2.89 (s, 1H).

    [0326] 1-(p-Bromophenyl)-1-phenyl-2-propyn-1-ol (1.9 g, 6.6 mmol), 6-Bromo-2-naphthol (1.5 g, 6.6 mmol), and p-Toluenesulfonic acid (94 mg, 0.5 mmol) are suspended in chloroform (300 mL), and the mixture is stirred at room temperature for 18 h. The crude product precipitates, is filtered, and washed with aqueous sodium hydroxide solution (1 M) and water. The crude product is purified crystallization from ethyl acetate to yield the dibromo naphthopyran as a white solid (2.5 g, 77%).

    [0327] .sup.1H NMR (500 MHz, Chloroform-d) 7.86 (d, J=2.0 Hz, 1H), 7.80 (d, J=9.1 Hz, 1H), 7.56 (d, J=8.9 Hz, 1H), 7.52 (dd, J=9.0, 2.1 Hz, 1H), 7.51-7.42 (m, 4H), 7.38-7.31 (m, 4H), 7.31-7.27 (m, 1H), 7.27-7.23 (m, 1H), 7.19 (dd, J=8.9, 0.7 Hz, 1H), 6.22 (d, J=9.9 Hz, 1H).

    [0328] The dibromo naphthopyran (1.0 g, 2.0 mmol) is dissolved in dry tetrahydrofuran (20 mL) under an argon atmosphere and cooled to 78 C. n-Butyl lithium (4.5 mmol, 2.5 M in hexanes) is added dropwise. After stirring for 30 min at 78 C., N-Methoxy-N-methylbenzamide (0.68 g, 4.5 mmol) is added and the mixture is stirred for 30 min at 78 C. The reaction mixture is allowed to warm to room temperature. The reaction is stirred for 2 h at room temperature and 1 M aqueous hydrochloric (20 mL) acid is added. The mixture is stirred for 20 min, 1 M aqueous NaOH solution is added (40 mL) and the mixture is extracted with ethyl acetate. The combined organic layers are dried over anhydrous MgSO.sub.4 and evaporated under reduced pressure. The residue is purified by silica-gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the compound PM-6 as a solid (0.52 g, 47%).

    [0329] .sup.1H NMR (500 MHz, Chloroform-d) 8.17 (d, J=1.8 Hz, 1H), 8.06 (d, J=8.8 Hz, 1H), 7.97 (dd, J=8.8, 1.8 Hz, 1H), 7.84-7.81 (m, 2H), 7.81-7.72 (m, 5H), 7.64-7.60 (m, 3H), 7.60-7.55 (m, 1H), 7.53-7.48 (m, 4H), 7.48-7.44 (m, 2H), 7.42-7.34 (m, 3H), 7.33-7.27 (m, 2H), 6.34 (d, J=10.0 Hz, 1H).

    Synthesis of Comparative Compound C1

    ##STR00059##

    [0330] 1,1-Diphenyl-2-propyn-1-ol (1.7 g, 8.2 mmol) and 4-Bromo-2-naphthol (1 g, 4.5 mmol) are suspended in toluene (20 mL) and heated to 60 C. p-Toluenesulfonic acid (13 mg, 0.07 mmol) is added, and the mixture is stirred at 60 C. for 2 h. After cooling to room temperature ethyl acetate is added and the organic phase is washed with aqueous sodium hydroxide solution (1 M), water, and saturated aqueous sodium chloride solution. The remaining organic phase is dried over anhydrous magnesium sulfate and the solvents are removed under reduced pressure. The crude product is purified by silica gel column chromatography using petroleum ether/ethyl acetate (9/1) as eluent to yield the halogenated naphthopyran as a white solid (0.77 g, 40%). The halogenated naphthopyran (0.77 g, 1.9 mmol) is dissolved in dry tetrahydrofuran (10 mL) under an argon atmosphere and cooled to 78 C. n-Butyl lithium (2.0 mmol, 2.5 M in hexanes) is added dropwise. After stirring for 45 min at 78 C., N-Methoxy-N-methylbenzamide (0.44 g, 2.9 mmol) is added and the mixture is stirred for 30 min at 78 C. The reaction mixture is allowed to warm to room temperature. The reaction is stirred for 3 h at room temperature and 1 M aqueous hydrochloric (10 mL) acid is added. The mixture is stirred for 20 min, 1 M aqueous NaOH solution is added (20 mL) and the mixture is extracted with ethyl acetate. The combined organic layers are dried over anhydrous MgSO.sub.4 and evaporated under reduced pressure. The residue is purified by silica-gel column chromatography using petroleum ether/ethyl acetate (10/1) as eluent to yield the compound C-1 as a solid (0.4 g, 49%).

    [0331] .sup.1H NMR (500 MHz, Chloroform-d) 8.49-8.41 (m, 1H), 8.26 (dd, J=8.0, 1.5 Hz, 1H), 7.88-7.80 (m, 2H), 7.61-7.56 (m, 1H), 7.56-7.48 (m, 6H), 7.45 (t, J=7.7 Hz, 2H), 7.38-7.32 (m, 5H), 7.32-7.26 (m, 2H), 6.67 (d, J=9.8 Hz, 1H), 6.23 (d, J=9.7 Hz, 1H).

    C-2

    ##STR00060##

    [0332] The synthesis of comparative compound C-2 is disclosed in Pozzo et al. Helvetica Chimica Acta, 1997, 80, 3, 725-738.

    ##STR00061##

    [0333] The synthesis of comparative compound C-3 is disclosed in WO 2020/245456 A1.

    [0334] The following Table 1 shows the reactivity of the respective formulations 1-9 under simultaneous irradiation with 375 nm (Formulations 1-3, 5-8: 4.5 mW/cm.sup.2; Formulations 4,9: 12.5 mW/cm.sup.2) and 455 nm (26.8 mW/cm.sup.2) in an experiment according to FIG. 1. The table gives the time until curing or solidification or a phase transition in the volumes which are irradiated with both wavelengths is observed. After the given time a similar curing or solidification or phase transition is not observed in the volumes which are irradiated with only one wavelength. Typically, an object is formed on at least one of the transparent layers according to FIG. 1. The object can be washed with solvent and further analyzed or isolated. Homogeneous irradiation was performed using LEDs M455L2 and M375L4 each in combination with an adjustable collimation adapter SM2F32-A, all available from Thorlabs inc. The intensity has been measured with a power meter consisting of PM400 and PM16-130, available from Thorlabs inc. The thickness of the volume has been adjusted to 0.65 mm.

    TABLE-US-00001 TABLE 1 Comparative Formulations for different dual color photoinitiators Reaction No. DCPI DCM TEOA PETA ACMO MDEA UDMA time 1 C1 1 mL 300 mg 1 g >10 min 12 mg 2 PM-4 1 mL 300 mg 1 g 3 min 12 mg 3 PM-1 1.4 g 1 g 20.4 g 1.5 min 16.3 mg 4 PM-2 1.4 g 1 g 20.4 g 12 min 8.2 mg 5 PM-3 0.7 g 0.5 g 10.2 g 40 s 8.4 mg 6 PM-4 1.4 g 1 g 21.4 g 40 s 16.3 mg 7 PM-5 1.4 g 1 g 20.2 g 30 s 16.5 mg 8 C-1 1.4 g 1 g 21.4 g 5.5 min 16.3 mg 9 C-2 0.7 g 0.5 g 10.2 g 15 min 7.9 mg

    [0335] Comparing the reactivity of different naphthopyrans in the same formulation surprisingly reveals that [2,1-b]naphthopyran is a more reactive dual color photoinitiator than [1,2-b]naphthopyran (No. 4 and 9). Furthermore, the introduction of carbonyl substituents results in an increased reactivity (No. 4 and 7). Also for carbonyl substituted derivatives the reactivity of [2,1-b]naphthopyran derivatives is surprisingly higher than the reactivity of the respective [1,2-b]naphthopyran (No. 1 and 2; No. 6 and 8). The higher reactivity for carbonyl substituted [2,1-b]naphthopyran derivatives is independent of the positioning of the carbonyl group (No. 3, 6, and 7). The two aryl substituents on the [2,1-b]naphthopyran are not limited to unsubstituted phenyl substituents (No. 5). Surprisingly cured resins from formulations containing [2,1-b]naphthopyrans showed little or no coloring directly after polymerization without further post treatment of the printed object. Specifically, the absorption of printed objects between 450 nm and 800 nm was found to be neglectable. For some [2,1-b]naphthopyrans no absorption in the cured objects has been observed in the region between 400 nm and 1000 nm. The objects also remain colorless or little colored when stored under ambient light conditions. The cured resin of formulation No. 8 is colored, similar to objects described in the state of the art (European Polymer Journal, 2023, 196, 112312 and Nature, 2020, 588, 620). FIG. 4 shows absorption spectra of the comparative objects which have been obtained using the conditions given in Table 1.

    [0336] While the documents cited in the state of the art concentrate on acrylate based resins in dual color volumetric printing, it may be advantageous to include thiol based monomers or oligomers in a formulation. Thiol based monomers such as Trimethylolpropane tris(3-mercaptopropionate) (TMPMP) or Pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) may lead to a more controlled polymerization yielding less brittle materials. Furthermore, oxygen inhibition is a common problem in polymerization techniques which rely on low concentrations of photoinitiators such as dual color volumetric printing. Thiols may be helpful to decrease the oxygen inhibition and can act as chain-transfer agents. Additionally, thiols can act as co-initiators and may be used to substitute the otherwise employed amine co-initiator resulting in formulations with reduced or no amine content. A low amine content is especially relevant for non or low yellowing materials. Therefore, there is a need for dual color photoinitiators which are compatible and reactive with thiols. No such dual color photoinitiator is known from the state of the art.

    [0337] The following Table 2 shows the reactivity of the respective formulations 10-13 under simultaneous irradiation with 375 nm (4.5 mW/cm.sup.2) and 455 nm (26.8 mW/cm.sup.2) in an experiment according to FIG. 1. The table gives the time until curing or solidification or a phase transition in the volumes which are irradiated with both wavelength is observed. After the given time a similar curing or solidification or phase transition is not observed in the volumes which are irradiated with only one wavelength. Homogeneous irradiation was performed using LEDs M455L2 and M375L4 each in combination with an adjustable collimation adapter SM2F32-A, all available from Thorlabs inc. The intensity has been measured with a power meter consisting of PM400 and PM16-130, available from Thorlabs inc. The thickness of the volume has been adjusted to 0.65 mm.

    TABLE-US-00002 TABLE 2 Reactivity of formulations containing the thiol-based monomer TMPMP and dual color photoinitiators Co- Reaction No. PM-5 ACMO Initiator UDMA TMPMP time 10 8.2 mg 0.7 g MDEA 10.0 g 0.5 g 30 s 0.5 g 11 8.4 mg 0.7 g MDEA 9.2 g 1.0 g 30 s 0.5 g 12 8.0 mg 0.7 g 9.7 g 1.0 g 3 min 13 12.4 mg 0.7 g 10.6 g 6.3 g 2.5 min

    [0338] Naphthopyran based dual color photoinitiators show high reactivity and a dual color effect in formulations containing thiol-based monomers. The reactivity of formulations with and without thiol are similar (No. 7, 10, 11). Furthermore, in presence of a thiol an amine-based co-initiator is not necessarily required (No. 12). Naphthopyran based dual color photoinitiators may also be suitable for resins, where the number of thiol moieties and the number of ene moieties are similar or equal (No. 13). Formulations containing thiols form more homogenous networks due to an at least partial step-growth mechanism in contrast to a pure free radical polymerization. This results in more flexible and less brittle materials. A further advantage lies in the reduced oxygen inhibition, which is of high importance as in volumetric printing approaches the exclusion of oxygen from highly viscous resins is difficult. It is known from the state of the art, that spiropyrans react with thiols in a dark reaction, which may interfere with the dual color polymerization (Phys. Chem. Chem. Phys. 2014, 16, 12137) and may render them not suited for conducting thiol-ene polymerizations.

    [0339] Surprisingly, the employed naphthopyran-based dual color photoinitiators do not seem to suffer from such a reaction and can be utilized when thiols are present in the formulation.

    [0340] According to the documents cited in the state of the art, the typically employed co-initiator is a derivative of ethanolamine, usually N-Methyldiethanolamine or Triethanolamine. Ethanolamine derivates are highly reactive co-initiators but suffer from low long-term stability and yellowing of the cured material. Furthermore, such co-initiators are of low molecular weight, allowing for migration and leakage of residual co-initiators from the cured object. To prevent leakage and migration oligomer-bound co-initiators on the basis of aminobenzoic acid derivatives have been invented. Therefore, there is a need for dual color photoinitiators which are compatible and reactive with derivatives of aminobenzoic acid or other co-initiators of lower reactivity. No such dual color photoinitiator is known from the state of the art.

    [0341] The following Table 3 shows the reactivity of the respective formulations 14-17 under simultaneous irradiation with 375 nm (Formulations 15-17: 4.5 mW/cm.sup.2) or 405 nm (Formulation 15: 18 mW/cm.sup.2) and 455 nm (26.8 mW/cm.sup.2) in an experiment according to FIG. 1. The table gives the time until curing or solidification or a phase transition in the volumes which are irradiated with both wavelength is observed. After the given time a similar curing or solidification or phase transition is not observed in the volumes which are irradiated with only one wavelength. Homogeneous irradiation was performed using LEDs M455L2 and M375L4 each in combination with an adjustable collimation adapter SM2F32-A, all available from Thorlabs inc. The intensity has been measured with a power meter consisting of PM400 and PM16-130, available from Thorlabs inc. The thickness of the volume has been adjusted to 0.65 mm.

    TABLE-US-00003 TABLE 3 Example formulations with co-initiators and additives Reac- co- Addi- tion No. PM-5 ACMO initiator UDMA tive time 14 26.9 mg 0.35 g 5.0 g I907 9 min 49 mg 15 8.2 mg 0.7 g EHDBA 10.7 g 6 min 500 mg 16 8.2 mg 0.7 g EHDBA 10.7 g DPI 2 min 500 mg 50 mg 17 4.7 mg 0.35 g 5.0 g DPI 6 min 56 mg

    [0342] Naphthopyran based dual color photoinitiators show reactivity and a dual color effect in formulations containing the type1 initiator 1907 instead of a co-initiator (No. 14). Surprisingly also the EHDBA co-initiator which is not based on ethanolamine has been found to be reactive. Even more surprisingly a synergistic effect has been found, when the EHDBA co-initiator is combined with an iodonium salt (No, 15, 16, 17) resulting in an increased reactivity.

    [0343] For the evaluation of the performance of a dual color photoinitiator in volumetric printing a respective volumetric printing experiment has been conducted. The typically applied wavelength 405 nm has been chosen as the first wavelength supplied from a laser source, while the second wavelength has been chosen as 455 nm (50-300 mW/cm.sup.2) supplied from a modified LED projector. The setup for volumetric printing is as follows: a cuvette with four transparent windows was filled with the resin and was irradiated in one direction with a light sheet of wavelength 1, while an image is projected onto the light sheet from a different angle (90) with wavelength 2. The image is changed to produce a movie, while the light sheet is moved through the cuvette. The prints result in solidification only in volumes where the light of both wavelengths intersects. The residual uncured resin is removed to obtain the shaped body, which is further washed with ethanol and post-processed. As a first reference object a cube has been chosen with the dimensions 7 mm7 mm7 mm, where a rectangular hole of 2 mm2 mm width connects the center of a first face with the center of the cube and the center of the cube with a second face, wherein the first face and the second face are adjacent faces. In other words, a rectangular tubing or channel connects two adjacent faces via the center of the cube. In a successful print the tubing is free to let a liquid such as the washing solvent run from one face to an adjacent face through the cube. Another reference object may be a spring which connects two plates. In a successful print the spring is functional and can be reversible compressed in a range given by the material properties. Table 4 lists formulations for volumetric printing. The concentration has been adjusted to assure for an absorbance at the first wavelength of 0.2 to 0.5 in the initial state, resulting in comparable uptake of light of the first wavelength. The printing speed has been chosen as 1 mm/min.

    TABLE-US-00004 TABLE 4 Formulations for volumetric printing of complex objects Co- 405 nm No. DCPI ACMO initiator UDMA TMPMP Additive Intensity 18 PM-1 1 g MDEA 20.4 g 15 mW/mm.sup.2 12.8 mg 2 g 19 PM-3 1 g MDEA 20.3 g 15 mW/mm.sup.2 3.3 mg 2 g 20 PM-4 1 g MDEA 20.5 g 3.7 mW/mm.sup.2 1.6 mg 2 g 21 PM-5 1 g MDEA 20.4 g 0.8 mW/mm.sup.2 1.4 mg 2 g 22 C-1 1 g MDEA 20.1 g 0-20 mW/mm.sup.2 4.5 mg 2 g 23 PM-5 MDEA 19.3 g 2 g 1.1 mW/mm.sup.2 1.65 mg 2 g 24 PM-5 1 g EHDBA 20.3 g DPI 5 mw/mm.sup.2 1.9 mg 2 g 0.2 g 25 C-3 0.5 g MDEA 10.1 g 0-10 mW/mm.sup.2 8.9 mg 1 g 26 C-3 MDEA 10.2 g 1 g 0-10 mW/mm.sup.2 9.1 mg 1 g

    [0344] For comparison with the state of the art formulations 1 and 2 have been tested. The viscosity of both formulations has been measured to 0.062 Pa s using a Kinexus+ Rheometer supplied by Netzsch. With such low viscosity volumetric dual color printing is usually not possible, since any cured voxel floats away from its position. Therefore, no print has been observed for No. 1 and 2. The [2,1-b]naphthopyran derivatives PM-1, PM-3, PM-4, and PM-5 have been successfully tested with the conditions given in table 4, resulting in a free channel through the cube and a reversible compressible spring (No. 18-21). Printing of the same complex objects has also been achieved with formulations No 23 and 24, with the conditions given in table 4 and resulting in a free channel through the cube and a reversible compressible spring. Surprisingly, the comparative experiment with the [1,2-b]naphthopyran C1 or the spiropyran C-3 did not result in a printed object. When No. 8 or 22 is subjected to the printing process no curing is observed, even at the highest intensity the setup could supply. Also a reduction in print speed to 0.5 mm/min which increased the energy uptake did not result in any curing. Both formulations showed absorbance at 405 nm between 0.2 and 0.5. Attempts to print complex objects using formulations No. 25 and 26 did neither result in a cube with a free channel nor in a reversible compressible spring.

    [0345] It has to be further noted, that the printed objects are colorless, while objects manufactured with dual color photoinitiators according to the state of the art are intensely colored.

    [0346] Resin R-1 is prepared from PM-6 (1.7 mg), EHDBA (2 g), TMPMP (1 g), Polyethyleneglycole (MW 200, 1.5 g), Aerosil 200 (300 mg), and UDMA (22.4 g). The resin R-1 is used for printing in a setup with a light sheet (375 nm), a projector (430 nm-650 nm) and a moved cuvette as shown in FIGS. 5 and 6. The following objects have been printed: A cube in the dimensions of 8 mm8 mm8 mm comprising a channel with a width of 1.5 mm which connects three neighboring faces of the cube via the center. [0347] A plate of the dimensions of 7 mm12 mm and a thickness of 1.5 mm, where cylindrical columns with an aspect ratio of 2:1 (height:width) are printed on one side of the plate. The columns have increasing diameters ranging from 50 m to 1000 m. [0348] A cube in the dimensions of 8 mm8 mm8 mm with a regular open pore structure and a wall thickness of 1 mm (gyroid structure). A cube in the dimensions of 8 mm8 mm8 mm with a regular open pore structure and a wall thickness of 2 mm (gyroid structure). [0349] A model of The Thinker by Aguste Rodin in a height of 11.5 mm. [0350] A cube in the dimensions of 8 mm8 mm8 mm, wherein each pair of opposing faces is connected by 9 straight cylindrical channels with a diameter of 1.2 mm, forming a regular porous structure. DCPI: Dual color photoinitiator [0351] DCM: Dichloromethane [0352] TEOA: Triethanolamine [0353] PETA: Pentaerythritol Tetraacrylate [0354] ACMO: Acryloylmorpholine [0355] MDEA: N-Methyldiethanolamine [0356] UDMA: Urethane Dimethacrylate (CAS 72869-86-4) [0357] TMPMP: Trimethylolpropane tris(3-mercaptopropionate) [0358] EHDBA: 2-Ethylhexyl 4-(dimethylamino)benzoate [0359] DPI: Diphenyliodonium hexafluorophosphate [0360] I907: 2-Methyl-4-(methylthio)-2-morpholinopropiophenon

    [0361] The features disclosed in the foregoing description and in the dependent claims may, both separately and in any combination thereof, be material for realizing the aspects of the disclosure made in the independent claims, in diverse forms thereof.