FIELD OF THE INVENTION

The invention relates to new 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives, a method for producing new 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives, new photoinitiating systems for photoinitiated cationic, radical, thiol-ene and hybrid polymerization processes, and use of new 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives.

The new photoinitiating systems according to the invention can be used for photoinitiation with light from the ultraviolet range and from the visible range of photoinitiated cationic, radical, thiol-ene and hybrid polymerization processes of monomers potentially for printing, dentistry, medicine, stereolithography, 3D printing and production of colored varnishes, paints and photocurable adhesives and also for production of colorless varnishes, paints and photocurable adhesives.

The new photoinitiating systems according to the invention can be used for photoinitiating ultraviolet and visible range light for photoinitiated atom transfer radical polymerization (photo-ATRP) processes.

BACKGROUND OF THE INVENTION

Photoinitiating systems for simultaneous initiation of all types of photopolymerization processes

Nowadays, state-of-the-art technologies for producing polymeric materials are based on photochemically initiated processes. The synthesis of polymeric materials carried out by photopolymerization is one of the most efficient methods, thanks to which it is currently a very widespread and still rapidly developing technique. Polymerization by means of light, mainly ultraviolet (UV) radiation, was initially used primarily in the coating industry, mainly in varnishing for solvent-free paints and varnishes for the furniture and automotive industries. This is because with photopolymerization, it is possible to achieve high polymerization rates within fractions of a second, resulting from the rapid formation of radicals or initiator ions, which allows high throughput of the production line. In addition, the possibility of conducting photopolymerization processes at ambient temperature makes the obtaining of polymeric materials carried out by photoinduced polymerization one of the most efficient photochemical technologies. Currently, this type of polymerization is used in many industrial fields, namely in photolithography for the manufacture of printed circuits, in microreplication for the manufacture of spherical lenses, for the photo-curing of polymer adhesives, and in microelectronics for the encapsulation of integrated circuits. A different direction of application for photopolymerization, which enables printing on plastic or metal materials, is the rapidly growing printing industry. In the printing industry, photopolymerization processes are used during the coating of photo- curable solvent-free UV varnishes and photo-curable printing inks, as well as during the lamination process, where photo-curable adhesives are used. Photopolymerization is also playing an increasingly important role in the design and molding of three-dimensional models using stereolithography as well as 3D printing, and in medicine for obtaining hydrogel polymer materials and for producing new photo-curable filling materials in dentistry. Therefore, photoinitiated polymerization is gaining importance in global markets as an easy, energy- efficient and environmentally benign method for obtaining cross-linked polymers.

The growing interest in photopolymerization is prompting the search for new types of high-performance photoinitiators, since their properties determine the efficiency and speed of polymerization. An additional aspect currently being pursued is the development of photoinitiators or photoinitiating systems characterized not only by their efficiency in the initiation process but also by their versatility. Versatility in this regard is related to the suitability of photoinitiator systems for various types of photopolymerization processes, including cationic photopolymerization, free radical photopolymerization, thiol-ene photopolymerization and hybrid photopolymerization. Accordingly, photoinitiators or photoinitiating systems that give the ability to simultaneously initiate all these types of photopolymerization processes are being sought.

Currently, it is crucial that new initiator systems or photoinitiators allow operation using ultraviolet (UV) and visible (Vis) light in the emission range of UV-LEDs (with emission maximum wavelengths of 365 nm, 385 nm or 395 nm) and Vis-LEDs emitting in the visible range, particularly at 405 nm or even 420 nm. Currently, LEDs in both the UV and visible ranges are becoming eco-friendly and alternative to mercury lamps as light sources in the photochemical industry. Therefore, the possibility of applying the developed initiating systems using light emitters equipped with LEDs was an additional aspect motivating the present research work. Illuminators based on UV- LED or Vis-LED light-emitting diodes allow the photopolymerization process to proceed without ozone emissions and emit minimal heat, which are very important features that distinguish this type of system from the traditionally used mercury lamps. With LED's it is easy to control the intensity of the emitted light, it is even possible to use pulsed irradiation. LED irradiators can be successfully used wherever soft irradiation is required, for example, during printing of temperature-sensitive surfaces, i.e.: some plastics. The most popular currently used wavelengths of light-emitting diodes are λ _max =385 nm or 395 nm and λ _max =405 nm, which is due to the very favorable price of radiators based on these systems. Nevertheless, the technology of photochemical surface curing using both UV and Vis LEDs also has fundamental limitations; namely, the main factor inhibiting the expansive development of this technique is still the lack of effective photoinitiating circuits that would show compatibility with the emission of commercially available light-emitting diode-based emitters.

Living photopolymerization and controlled photopolymerization processes

Controlled radical polymerization (GRP) has revolutionized polymer science, enabling user-friendly synthesis of materials - polymers with precisely defined average molecular weights and architectures. Obtaining polymers with specific properties, i.e., molecular weight and low polydispersity, is particularly important when studying, among other things, the physico-chemical properties and rheological properties of polymers with a view to future application of these materials. CRP processes comprise a group of radical polymerization methods that are very popular due to the fact, that they have provided simple routes for the synthesis of well-defined polymers as new functional materials. Among all controlled radical polymerization (CRP) methods, radical polymerization with atom transfer (ATRP) is probably the most widely used method. The basis for the operation of ATRP processes is a redox reaction - involving a metal-based catalyst (metal Cu (I), Ru (II), Fe (II)) in the presence of suitable ligands. Contamination of the final product with the metals involved in the catalytic system is a problem and is a huge limitation of applications of the ATRP technique, e.g. in microelectronics or biomaterials. Recently, several systems have been developed that allowed ATRP reactions involving very low values of copper catalyst at [ppm] values. This is possible in the presence of various reducing agents that continuously regenerate Cu(l) activators from Cu(ll) deactivators and compensate for radical termination. Reducing agents used in activator regeneration in the electron transfer process include various organic compounds such as ascorbic acid, sugars or inorganic compounds such as tin(ll) complexes, metals or hydrazine. In the aforementioned systems, the concentration of the metal catalyst can be reduced to a concentration of about 100 ppm. This catalyst content can remain in products for less demanding applications. There are also options for removing residual catalyst by dialysis, precipitation or filtration. Nevertheless, such approaches are time-consuming making them unpopular. Currently, it is very important to strive to streamline and improve CRP methods by eliminating toxic reactants - such as metal complexes. It is also worth noting that photochemically initiated reactions have recently gained great popularity in controlled radical reaction (CRP) methods. The development of photoinduced radical polymerization with atom transfer (photo-ATRP) was considered a milestone in polymer chemistry, but the catalytic system still remained a problem. However, organic catalysts such as phenothiazine derivatives in combination with alkyl halides have been shown to be effective photocatalytic systems for controlled radical reactions (CRP) without metal-containing compounds. In connection with the above, it is highly desirable to develop new catalytic systems for photocatalytic CRP processes without the use of transition metal-based compounds and tailored to market needs related to the introduction of state-of-the-art and safe Vis- LED light sources.

BACKGROUND OF THE INVENTION

From the Polish patent description Pat, 238050 are known derivatives of 2-amino-4,6-diphenylbenzene-1,3- dicarbonitrile with general formula (I) in which

R ₁ substituent stands for hydrogen atom -H, phenyl group -C ₆ H ₅ , group -C ₂ H ₅ ;

R ₂ substituent stands for hydrogen atom -H, group -CH ₃ , group -C ₂ H ₅ either the substituents R ₁ and R ₂ , together with the nitrogen atom to which they are attached, form a five- membered unsaturated ring constituting a pyrrole group; R ₃ substituent stands for hydrogen atom -H, bromine atom -Br, methylsulfanyl group -SCH ₃ , phenyl group -C ₆ H ₅ , substituted phenyl group , in which the substituent R ₅ indicates a group: -OCH ₃ , -N(C ₆ H ₅ ) ₂ , -CN,

-SCH ₃ , , or the substituent R ₃ stands for a group selected from the following::

R ₄ substituent stands for hydrogen atom -H, bromine atom -Br, methylsulfanyl group -SCH ₃ , substituted phenyl group -C ₆ H ₄ -SCH ₃ , whereby when the substituents R ₁ , R ₂ and R ₄ simultaneously denote the hydrogen atom -H, the substituent R3 is distinct from the hydrogen atom -H, from the bromine atom -Br and from the substituted phenyl group in which the substituent R ₅ indicates a group: -OCH ₃ , -CN, -SCH ₃ .

The subject matter of the invention according to Pat.238050 also includes methods of producing compounds of general formula (I), as well as new photoinitiating systems for cationic, radical, thiol-ene and hybrid photoinitiated polymerization processes, containing onium salts and co-initiator, characterized in that they contain a) at least one onium salt, in an amount of 1% by weight of the composition containing the monomer and photoinitiating system, with the onium salt selected among the following: - iodonium salts selected from among diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4'- dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4’-isopropyl-diphenyliodonium tetrakis pentafluorophenylborate;

- sulfonium salts selected from triarylsulfonium hexafluorophosphate and triarylsulfonium hexafluoroantimonate;; and b) at least one co-initiator, in an amount of 0.1 % by weight of the composition containing the monomer and a photoinitiating system , the co-initiator being selected from the group of 2-amino-4,6- diphenylbenzene-1,3-dicarbonitrile derivatives of general formula (I) in which the meaning of the substituents from R ₁ to R ₄ is defined above.

In addition, the subject of the invention according to Pat.238050 is the use of 2-amino-4,6-diphenylbenzene-1,3- dicarbonitrile derivatives of general formula (I): wherein the meaning of the substituents from R ₁ to R ₄ is set forth above, as co-initiators in photoinitiating systems for photoinitiated cationic, radical, thiol-ene and hybrid polymerization processes containing onium salts selected from the group consisting of iodonium salts selected from diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4'- dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4'-isopropyl diphenyliodonium tetrakis pentafluoro- phenylborate, sulfonyl salts selected from triphenylsulfonyl hexafluorophosphate and triphenylsulfonyl hexafluoroantimonate, in which photoinitiating systems the content of onium salts is 1% by weight, and the co- initiator content is 0.1% by weight, in relation to the weight of the monomer composition with the photoinitiating system undergoing photopolymerization.

DETAILED DESCRIPTION OF THE INVENTION

The object of the invention is new 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives with general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond

that is, compounds selected from a group including:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile 4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-pheny l-benzene- 1 , 3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilino]p henyl]benzene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6-phe nyl-benzene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzene-1 ,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile 4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benzene- 1,3-dicarbonitrile 2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile

The new compounds according to the invention, as well as their chemical names and acronyms, are listed in Table 1 below.

Table 1. New compounds of the invention.

To obtain the compounds according to the invention, the syntheses of the necessary known intermediates were carried out by known means.

Initially, compounds with the general formula (1‘) were produced,

The method used was characterized as including the following steps:

- step A, in which bromobenzaldehyde of general formula (2) was treated with malononitrile, in methanol or ethanol medium in the presence of NaOH or KOH as a base catalyst, and the reaction was carried out at room temperature for a period of one hour, after which the product obtained as a precipitate with the general formula (2‘) was purified by crystallization from methanol or ethanol and dried;

- step B, in which an acetophenone derivative with the general formula (3) was treated with malononitrile, in the medium of toluene, in the presence of ammonium acetate and acetic acid, heating the reaction mixture to boiling for 4 hours, after which the solvent was evaporated and water was added to the residue and the whole was extracted with ethyl acetate to obtain the product with the general formula (3') after evaporation of the solvent, product was purified by crystallization from a solvent selected from methanol, ethanol, isopropanol;

- step C, in which the product of step A was reacted with the product of step B, carrying out the reaction in an organic solvent selected from acetonitrile and dichloroethane, in the presence of piperidine as a catalyst, at room temperature within an hour, and then at the boiling point of the solvent within an hour, after which, after cooling the reaction mixture, the resulting product was separated as a precipitate, washed with cold solvent and dried.

Subsequently, compounds with the general formula (1") were obtained

It was done in such a way that compounds of general formula (1 ') was reacted with iodoethane, carrying out the reaction in N, N-dimethylformamide in the presence of NaOH, at 60°C for 6 hours, after which water was added and the whole thing was extracted with ethyl acetate, the combined organic layers were washed with brine, dried over Na ₂ SO ₄ to obtain the product, which was purified chromatographically.

The object of the invention is a method of producing new compounds according to the invention.

Method of producing new 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds selected from a group including:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-be nzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethy(amino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzen e-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile is characterized in that the 2-(diethylamino)-4-(4-bromophenyl)-6-phenylbenzene-1,3-dicar bonitrile derivative with the formula (1") undergoes a coupling reaction with an amine, which is, depending on the compound obtained: A1) an amine of general formula (4) in which the substituent R ₃ denotes a hydrogen atom, cyano group, methyl group, trifluoromethyl group, fluorine atom, methylsulfanyl group, and the substituent R ₄ denotes a hydrogen atom, methyl group or phenyl group;

A2) piperidine;

A3) carbazole, whereby the reaction is carried out in the presence of the following reagents: a) an alkaline agent selected from a group that includes cesium(IV) carbonate CS ₂ CO ₃ , sodium carbonate Na ₂ CO ₃ , potassium carbonate K ₂ CO ₃ , potassium tertbutanolate KOt-Bu, sodium tertbutanolate NaOf-Bu, caesium pivalate CsOPiv, potassium acetate KOAc, triethylamine Et ₃ N, potassium phosphate b) a two-component palladium catalyst consisting of palladium acetate Pd(OAc) ₂ or Bis(dibenzylideneacetone)palladium(O) - Pd(dba) ₂ ) with the appropriate ligand selected from the following: 4,5- Bis(diphenylphosphino)-9,9-dimethylxanthene - Xantphos, 2-Dicyclohexylphosphino-2',6'-diisopropoxybiphenyl - RuPhos, (2-biphenyl)di-tert-butylphosphine - JohnPhos, (2-biphenyl) dicyclohexyl-phosphine - CyJohn Phos, 2- Dicyclohexylphosphino-2- (N,N-dimethylamino)-biphenyl - Dave Phos, tri-o-tolylphosphine, tri-tert- butylphosphine, 2-di-tert-butylphosphino-2',4',6'-triisopropylbiphenyl - tBu XPhos, 1 , 1 '-ferrocenediyl-bis (diphenylphosphine) - dppf, 1 ,T-binaphthalene-2,2'-diyl) bis (diphenylphosphine) - BINAP or c) single-component palladium catalyst selected from the following: chloro(2-dicyclohexylphosphino-2',4',6'- triisopropyl-1,1 ^, -biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(ll) - XPhos Pd G2, (2-dicyclohexyl-phosphino- 2', 4', 6 -triisopropyl- 1,1 ’-biphenyl) [2-(2-aminoethyl) phenyl)] palladium(ll) chloride - Xphos Pd G1 , chloro (2- dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl) [2-(2 -amino- 1,1 -biphenyl)] palladium (II) - RuPhos Pd G2, (2-dicyclohexylphosphino-2', 4', 6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1 -biphenyl)] palladium(ll) methanesulfonate - XPhos Pd G3 and d) solvent selected from toluene dioxane, tetrahydrofuran THF, tert-butanol - tBuOH, dimethylformamide DMF or isopropanol iPrOH, the chemicals are mixed together under an inert gas atmosphere of argon or nitrogen and heated 12h at 120°C, monitoring the reaction using TIC thin-layer chromatography, using a mixture of hexane and ethyl acetate as eluent and aluminum plates with silica gel applied with a 254 nm fluorescent tracer, after which water is added to the reactor and extraction is carried out with ethyl acetate, then the combined organic layers are washed with brine, dried over Na ₂ SO ₄ , the solvent is driven off and the reaction product is purified on a chromatography column.

Preferably, cesium carbonate(IV) is used as an alkaline agent CS ₂ CO ₃ , palladium acetate is used as a catalyst Pd(OAc) ₂ with ligand 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene - Xantphos or single-component palladium catalyst chloro(2-dicyclohexylphosphino-2',4 ^, ,6'-triisopropyl-1,1’-biphenyl)[2-(2’-amino-1,1'- biphenyl)]palladium(ll) - XPhos Pd G2, toluene is used as a solvent, and the chemicals are mixed under an argon atmosphere.

Also the subject of the present invention are new photoinitiating systems for photoinitiated cationic, radical, thiol- ene, hybrid polymerization processes, which contain onium salts and a photosensitizer, characterized in that they contain a) at least one onium salt selected from the following:

— iodonium salts selected from diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4'- dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4'-isopropyl-diphenyliodonium tetrakis pentafluorophenylborate;

— sulfonium salts selected from triarylsulfonium hexafluorophosphate and triarylsulfonium hexafluoroantimonate; and b) at least one photosensitizer selected from the group of new 2-(diethylamino)-4,6-diphenylbenzene-1,3- dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond

that is, at least one compound selected from the group comprising: 4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3-di carbonitrile 4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilino]p henyl]benzene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6-phe nyl-benzene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzene-1 ,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile 4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benzene- 1,3-dicarbonitrile 2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile with the molar ratio of photosensitizer to onium salt being in the range of 2 to 0.001.

Preferably, in the photoinitiating systems according to the invention, the onium salt is selected from a group including iodonium salts selected from diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl-diphenyliodonium hexafluorophosphate, 4,4'-dimethyl- diphenyliodonium hexafluorophosphate, 4-methyl-4'-isopropyl-diphenyliodonium tetrakis pentafluoro- phenylborate.

The various photoinitiating systems have applications in:

Cationic ring-opening polymerization of aann epoxy monomer (for example, 3,4- epoxycyclohexanecarboxylate 3,4-epoxycyclohexylmethyl monomer)

• Cationic chain polymerization of a vinyl monomer (for example, divinyl ether of triethylene glycol)

• radical polymerization for an acrylic or methoacrylate monomer (for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate)

• Hybrid polymerization for a mixture of epoxide and acrylate (or methacrylate) monomers

• Atom transfer polymerization (ATRP) for monomers polymerizing according to radical polymerization • Radical polymerization with reversible addition-fragmentation chain transfer (RAFT) for monomers polymerizing according to radical polymerization

The subject of the invention is also the use of new 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group that includes:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-be nzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzen e-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]be nzene-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile as photosensitizers in photoinitiating systems for photoinitiated cationic, radical, thiol-ene, and hybrid polymerization processes containing onium salts selected from the group including iodonium salts selected from diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4-dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4'- isopropyl diphenyliodonium tetrakis pentafluoro-phenylborate, sulfonium salts selected from triphenylsulfonium hexafluorophosphate and triphenylsulfonium hexafluoroantimonate, in which systems the molar ratio of the photosensitizer to the onium salt is between 2 and 0.001.

The subject of the invention is also the use of new 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group that includes:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-be nzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzene-1 ,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile as photosensitizers constituting a component in two-component photoinitiating systems for the initiation of photoinitiated radical polymerization processes under visible light, containing a second component in the form of an amine, acting as a co-initiator - proton donor, in the form of ethyl 4-(dimethylamino)benzoate, in which the molar ratio of photosensitizer to amine is contained in the range from 1 to 8. Moreover, the subject of the invention are new two-component photoinitiating systems for initiating radical photopolymerization, which are characterized by the fact that they contain as photosensitizers new derivatives of 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitrile with the general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group that includes: 4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3-di carbonitrile 4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilino]p henyl]benzene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzene-1 ,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile 4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benzene- 1,3-dicarbonitrile 2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile and contain amine: ethyl 4-(dimethylamino)benzoate acting as a co-initiator - a proton donor, in which systems the molar ratio of photosensitizer to amine is between 1 and 8.

The object of the invention is the use of new 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitriie derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group that includes:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-be nzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzen e-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]be nzene-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile as photosensitizers in three-component photoinitiating systems for the initiation of photoinitiated radical polymerization processes in the wavelength range of visible light, containing onium salt selected from iodonium salts: diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4'- dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4'-isopropyl diphenyliodonium tetrakis pentafluoro-phenylborate, and of the sulfonium salts: triphenylsulfonium hexafluorophosphate and triphenylsulfonium hexafluoroantimonate, and

- an amine that acts as a proton donor-coinitiator: ethyl 4-(dimethylamino)benzoate, in which initiator systems, the content of iodonium salt expressed in % by weight expressed with respect to the monomer used for photopolymerization is not less than 0.1% and not more than 10%; the content of photosensitizer expressed in % by weight expressed with respect to the monomer used for photopolymerization is not less than 0.1% and not more than 1%; the amine content expressed in % by weight expressed with respect to the monomer used for photopolymerization is not less than 0.5% and not more than 20%.

Also the subject of the invention are new ternary photoinitiating systems for initiating photoinitiated radical polymerization processes, in the wavelength range of visible light, which are characterized in that they contain:

- onium salt selected from iodonium salts: diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, 4-methyl-4'-isopropyl diphenyliodonium hexafluorophosphate, 4,4'- dimethyldiphenyliodonium hexafluorophosphate, 4-methyl-4'-isopropyl diphenyliodonium tetrakis pentafluoro- phenylborate, and of the sulfonium salts: triphenylsulfonium hexafluorophosphate and triphenylsulfonium hexafluoranthimonate,

- an amine that acts as a proton donor-coinitiator: ethyl 4-(dimethylamino)benzoate, and

- a photosensitizer selected from new 2-(diethylamino)-4,6-diphenylbenzene-1, 3-dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group including:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cy anoanilino)phenyl]-2-(diethylamino)-6-phenyl-benzene- 1 , 3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1, 3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1, 3-dicarbonitrile

2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-b enzene-1, 3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6-phe nyl-benzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzen e-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]be nzene-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile in which initiation systems the content of iodonium salt expressed in weight % expressed with respect to the monomer used for photopolymerization is not less than 0.1% and not more than 10%; the content of photosensitizer expressed in % by weight expressed with respect to the monomer used for photopolymerization is not less than 0.1% and not more than 1%; the amine content expressed in % by weight expressed with respect to the monomer used for photopolymerization is not less than 0.5% and not more than 20%.

The subject of the invention is also the use of new 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond that is, compounds that are selected from a group that includes: 4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3-di carbonitrile 4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)aniljno]p henyl]benzene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile 2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6-phe nyl-benzene-1,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzene-1 ,3-dicarbonitrile 2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]benze ne-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile as photocatalysts in systems for initiating photoinduced atom transfer radical polymerization processes (photo - ATRP - Atom transfer radical polymerization = radical polymerization with atom transfer) in the visible light wavelength range, which are characterized by the fact that they contain the ATRP initiator ethyl a- bromophenylacetate (EBPA) or ethyl 2-bromoisobutyrate (EBiB) or 2-bromopropionitrile (PBN), methyl a- bromoisobutyrate (MBiB), tert-butyl a-bromoisobutyrate, 2-bromoisobutyryl bromide, the systems of which the molar ratio of photocatalyst to initiator is between 1 and 10.

Also the subject of the invention are new systems for initiating photoinduced atom transfer radical polymerization processes in the wavelength range of visible light, characterized in that they contain:

- atom transfer radical polymerization initiator - ethyl a-bromophenylacetate or ethyl 2-bromoisobutyrate or 2- bromopropionitrile, methyl a-bromoisobutyrate, tert-butyl a-bromoisobutyrate, 2-bromoisobutyryl bromide,

- a photocatalyst selected from new 2-(diethylamino)-4,6-diphenylbenzene-1,3-dicarbonitrile derivatives of general formula (1) in which R ₁ stands for: one of the following groups, where the dashed line indicates a bond this is a compound that is selected from a group that includes:

4-(4-anilinophenyl)-2-(diethylamino)-6-phenyl-benzene-1,3 -dicarbonitrile

4-[4-(4-cyanoanilino)phenyl]-2-(diethylamino)-6-phenyl-be nzene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-[4-(trifluoromethyl)anilin o]phenyl]benzene-1,3-dicarbonitriie 2-(diethylamino)-4-[4-(4-fluoroanilino)phenyl]-6-phenyl-benz ene-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(4-methylsulfanylanilino)phenyl]-6- phenyl-benzene-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(1-piperidyl)phenyl]benzen e-1,3-dicarbonitrile

2-(diethylamino)-4-phenyl-6-[4-(N-phenylanilino)phenyl]be nzene-1,3-dicarbonitrile

4-(4-carbazol-9-ylphenyl)-2-(diethylamino)-6-phenyl-benze ne-1,3-dicarbonitrile

2-(diethylamino)-4-[4-(N-methylanilino)phenyl]-6-phenyl-b enzene-1,3-dicarbonitrile in which systems the molar ratio of photocatalyst to initiator is between 1 and 10.

The invention is illustrated by the following examples.

Example 1 Method for chemical synthesis of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives

STEP 1A:

Bromobenzaldehyde (54 mmol, 1eq) and malononitrile (65 mmol, 1.2 eq) were dissolved in methanol (30 ml), alkaline catalyst - an aqueous solution of NaOH (0.27 mmol, 0.01eq in 5 ml of water) was added and stirred at room temperature for one hour. The solvent methanol (10 ml) was added to the resulting precipitate and crystallization was carried out. The resulting precipitate was drained, washed with cold methanol and air-dried.

STEP 1B:

Acetophenone (83 mmol, 1eq) and malononitrile (166 mmol, 2 eq) were dissolved in toluene (200 ml), ammonium acetate (17 mmol, 0.2 eq) and acetic acid (20 ml) were added. The resulting mixture was heated to boiling under a Dean-Stark cap for 4 hours. The solvent was evaporated, and water was added to the remaining oil and the whole extracted with ethyl acetate. The combined organic layers were washed with brine, dried over Na ₂ SO ₄ . After evaporation of the solvent, crystallization from methanol was carried out, the resulting precipitate was air- dried.

STEP 1C: The condensate of bromobenzaldehyde with malononitrile obtained in step 1A (43 mmol, 1 eq), the condensate of acetophenone with malononitrile obtained in step 1B (43 mmol, 1 eq) and the solvent acetonitrile (90 ml) were mixed together and the catalyst piperidine (6.25 ml) was added. The whole mixture was stirred at room temperature for one hour, and then at the boiling point of the solvent (reflux) for one hour. After the reaction mixture cooled, the resulting precipitate was drained and washed with cold acetonitrile, air-dried.

Step 2

The product from step 1C (8 mmol, 1eq) was dissolved in N,N-dimethylformamide (66 ml), NaOH (26 mmol, 3.3 eq) was added, followed by iodoethane (34 mmol, 4.2 eq), and the mixture was heated 5h at 60°C. Water was then added and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over Na ₂ SO ₄ . The product was purified on a chromatography column (SiO ₂ , hexane/ethyl acetate), purity was confirmed by TLC analysis using hexane/ethyl acetate eluent.

Step 3

Where: PK08-017 R ₄ = H, R ₃ = H PK05-186 R ₄ = CH ₃ , R ₃ = H PK08-012 R ₄ = Ph, R ₃ = H PK08-020 R ₄ = H, R ₃ = CN PK08-019 R ₄ = H, R ₃ = CH ₃ PK08-024 R ₄ = H, R ₃ = F PK08-022 R ₄ = H, R ₃ = CF ₃ PK08-023 R ₄ = H, R ₃ = SCH ₃

Buchwlad-Hartwig coupling reaction was carried out. The product from step 2, 2-(diethylamino)-4-(4- bromophenyl)-6-phenylbenzene-1,3-dicarbonitrile (0.58 mmol, 1eq), the corresponding amine (0.82 mmol, 1.4 eq.), alkaline agent base in the form of cesium carbonate(IV) CS ₂ CO ₃ (0.82 mmol, 1.4 eq), a two component palladium catalyst consisting of palladium acetate Pd(OAc) ₂ (0, 03 mmol, 0.05 eq) with the corresponding ligand 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene - Xantphos (0.03 mmol, 0.05 eq) and the solvent toluene (3.3 ml) were mixed together under an inert argon gas atmosphere and heated 12h at 120°C. The reaction was monitored by TLC thin-layer chromatography, using a mixture of hexane and ethyl acetate (in the appropriate volume ratio of 4:1) as eluent and Al Foils, silica gel matrix, with fluorescent indicator 254 nm. The progress of the reaction was observed in a UV chamber at 254nm. Water was then added and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over Na ₂ SO ₄ the solvent was driven off and purified in a chromatography column (SiO ₂ , hexane/ethyl acetate).

Table 2 Spectroscopic data of the obtained compounds

Example 2. Spectroscopic properties of the obtained 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives to determine their suitability to act as photosensitizers in photoinitiating systems.

Absorption properties

For absorption measurements of the 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives studied, a Silver Nova spectrometer from StellarNet Inc. (USA), which has a spectral range of 190-1100 nm. Measurements were made in spectroscopically pure acetonitrile (Sigma Aldrich), using a quartz cuvette with an optical path length of 1 cm. The light source was a deuterium-halogen lamp from StellarNet Inc. (USA). All measurements were performed at room temperature.

Fluorescence measurements

The apparatus for fluorescence studies consisted of a fluorescence excitation light source, for which a UV-LED emitting light diode with a wavelength of Amax = 320 nm (UVTOP315-BL-TO39, Roithner Laser Technik; a Silver Nova spectrometer, and a suitable measuring head,; such as described in I. Kaminska, J. Ortyl, R. Popielarz, Polym. Test. 2015, 42, 99. The fluorescence light from the measuring chamber was fed to the spectrometer using a fiber optic cable with a core diameter of 2 mm made of PMMA (Fibrochem Ltd.).

The first stage of the study was to measure the absorption of new derivatives of compounds based on the 2- (diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile system in acetonitrile. Spectroscopic analysis showed that virtually all of the obtained compounds absorb in the UV-VIS range reaching up to 450 nm (Fig. 1 and Fig. 2). The absorption spectra of some derivatives is shifted slightly toward shorter wavelengths, which may be due to the type of substituent present in the structure. The position of the absorption bands and their intensity mainly depend on the structure of the studied 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives. The most long- wavelength absorption band was recorded for the compound with the acronym PK05-171. In order to comprehensively understand the spectroscopic properties, fluorescence measurements were performed for selected 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives using an excitation λex max = 320 nm. The obtained fluorescence spectra are characterized by the presence of a single emission band, as shown in Fig. 3 nad Fig. 4. The nature of the fluorescence spectrum is strongly influenced by the type of substituent embedded in the structure of the compound. Compound PK05-171 shows the highest fluorescence intensity (Fig. 3), while compounds PK05-172, PK05-187 and PK05-167 show no fluorescence

Example 3. Determination of the electrochemical and thermodynamic properties of the developed derivatives of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile to determine their suitability as photosensitizers in systems that initiate photopolymerization processes.

To determine the suitability of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives for the role of photosensitizers in photoinitiated cationic, radical and hybrid polymerization processes (including thiol-ene), electrochemical and spectroscopic studies were carried out. Due to the mechanism of formation of active centers (cationic and/or radical) during the photopolymerization process, a photoinitiating system containing a photosensitizer (which is an electron donor) and a onium salt in its composition can be qualified as a photoinitiating system exhibiting so-called photoredox processes. In contrast to single-component initiators, in which processes of direct photo-separation of bonds that break under UV light take place, the action of photoinitiating systems consists in a photo-induced process of electron transfer between a photosensitizer acting also as a radiation absorber (it constitutes an electron donor - in the case of the present invention, these are selected derivatives of 2-(diethylamino)-4, 6-diphenylbenzene-1,3-carbonitrile, and the onium salt, while the initiators of polymerization (radicals, radical-cations, protons or cations) are formed by follow-up reactions after the electron transfer process. In an initiator system using the photoredox process, onium salts are used in the role of electron acceptor (for example, iodonium salts), but the selection of a suitable radiation absorber (acting as a photosensitizer, acting as an electron donor) that would effectively interact with the onium salt remains a challenge. Accordingly, the overarching research objective was to design and synthesize innovative radiation absorbers capable of effectively participating in the photoredox process and guaranteeing the obtaining of universal systems that initiate all types of photopolymerization. The method of photopolymerization using photoredox processes, in which an excited photosensitizer is oxidized by an electron acceptor, is much less common, and this despite the fact that it can be used to initiate radical and cationic photopolymerizations. This is due to the small number of compounds that have a sufficiently low oxidation potential. The versatility of applications of photoredox processes manifested by the possibility of initiating radical, cationic, thiol-ene and hybrid polymerizations prompts the search for new highly efficient radiation absorbers, which would be characterized by a broad absorption spectrum adapted to modern UV light sources. The oxidation potential of studied compounds were determined. In addition, an important parameter determining the suitability of molecules in a photoinitiating system operating according to the oxidation mechanism is the free energy change of electron transfer (AGet) between the individual components of the photoinitiating system. This process must be thermodynamically allowed, so the value of (AGet) determined from the Rehm-Weller equation must have a negative value. Accordingly, the values of the parameter (AGet) were also calculated. In order to determine the change in Gibbs enthalpy accompanying electron transfer in the compounds under study, the oxidation potentials of these compounds were measured by cyclic voltammetry and the emission and excitation spectra were examined using a Quanta MasterTM 40 spectrofluorimeter made by PTI. Obtaining negative values of the Gibbs free energy for the excited singlet states confirmed the ability of the electron transfer process to occur spontaneously between the components of the iodonium salt - terphenyl sensitizer inition system

The oxidation potential was measured by cyclic voltammetry (using an M161E electrochemical analyzer apparatus together with an M164D electrode stand equipped with a Faraday can made by MTM, Krakow), using a platinum electrode as the measuring electrode and a chlorosilver electrode as the comparison electrode. The primary electrolyte was tetrabutylammonium hexafluorophosphate (0.1 M). Example 4. Study of photopolymerization kinetics by real-time FT-IR to determine the suitability of the developed 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives for the role of photosensitizers of iodonium salts in initiating systems for photopolymerization processes.

The primary objective of the study undertaken was to determine the suitability of the newly developed photoinitiator systems containing the developed 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives and the onium salt for initiating the photopolymerization of monomers. To test the effectiveness of the developed systems in comparison with a single-component commercial photoinitiator, which was diaryliodonium salt coordinated with a hexafluorophosphate anion with the trade name Speedcure® 938 (Lambson), photopolymerization trials were conducted:

• cationic polymerization of an epoxide monomer (CADE, Sigma Aldrich)

• cationic polymerization of vinyl monomer (TEGDVE, Sigma Aldrich)

• radical polymerization for an acrylic monomer (TMPTA, Sigma Aldrich)

• hybrid polymerization for a mixture of epoxide (CADE, Sigma Aldrich) and acrylic monomers (TMPTA, Sigma Aldrich)

The method used to monitor the degree of monomer conversion during the photopolymerization processes was the real-time FT-IR method, an FTIR - i10 NICOLET™ spectrophotometer from Thermo Scientific equipped with a horizontal attachment was used. A visible range diode emitting light perpendicularly to the sample surface with wavelength λ _max = 405 nm or λ _max = 420 nm or possibly λ _max = 455 nm was used as the light source. Measurements were carried out for up to 800 or 600 seconds depending on the composition, and the resulting data were recorded in OMNIC, a program dedicated to processing FT-IR spectra. Data were recorded in a darkened room, where only lamps emitting red light were used as illumination.

Sample preparation for monitoring photopolymerization process by real time FT-IR metod

Compositions for real-time FT-IR studies were prepared in vials of dark orangish glass in a darkened room. Each composition contained 1% wt. Speedcure 938 iodonium salt initiator and a photosensitizer - 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives at a concentration of about 1·10 ^-3 mol·dm ^-3 relative to the total composition, which was 0.1%, of the respective 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives. A drop of the prepared composition, using a glass pipette, was applied to a pellet made of barium fluoride with a diameter = 25 0.2 mm x 5 0.1 mm for monitoring cationic photopolymerization processes. Once this was done, the pellet was placed on a metal holder and placed in the horizontal attachment of the spectrometer. Measurements were performed while maintaining the same thickness of the applied composition layer of 25 μm, respectively. A Vis-LED emitting light with wavelength 405 nm, 420nm or 455nm was turned on 10 seconds after running the OMNIC software recording the IR spectrum. All compositions were tested in a room with limited daylight. By combining the recording of the infrared spectrum of individual compositions over time, while simultaneously exposing the sample to a preset light source, it is possible to observe the photopolymerization reaction in real time. The change in peak intensity at the corresponding wave numbers (for the epoxy monomer 3,4-epoxycyclohexanecarboxylate-3,4-epoxycyclohexylmethyl (CADE) at 790 cm ^-1 , for the acrylic monomer TMPTA trimethylolpropane triacrylate at a wave number of 1634 cm ^-1 , and for the triethylene glycol divinyl ether TEGDVE 1620 cm ^-1 ) indicates that the photopolymerization process is proceeding efficiently. The conversion of functional groups can be calculated from the following formula:

C=(1-(A/A ₀ ))*100% gdzie:

C - Conversion

A - The value of the band area monitored during the photopolymerization process as a function of time A ₀ - initial value of the band area at the monitored wave number

Example 4 A: Ring-opening cationic photopolymerization for an epoxy monomer and cationic chain photopolymerization for a TEGDVE vinyl monomer

Then, using the data obtained in the real time FTIR experiment, the conversion of functional groups was calculated for compositions containing specific initiator systems based on diaryliodonium salt and a photosensitizer representing the corresponding 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivative. The data are presented in the graphs below ( Fig. 5 - Fig. 12 ) and in Table 5.

Investigations into the suitability of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives for the role of highly effective photosensitizers in a two-component initiator system containing an iodonium salt for initiating cationic photopolymerization processes of an epoxy monomer have shown that derivatives of 2-(diethylamino)- 4, 6-diphenylbenzene-1,3-carbonitrile can find application in initiating systems for initiating ring-opening cationic photopolymerization as well as cationic chain photopolymerization of vinyl monomer (TEGDVE) under visible irradiation.

Table 5. Comparison of the efficiency of initiation of cationic photopolymerization with a photoinitiating system composed of diaryliodonium salt (1%wt.) and the tested 2-(diethylamino)-4,6-diphenylbenzene-1,3-caibonitrile derivatives in the role of photosensitizers (0 1 %wt ) under irradiation with visible li ht (Vis) at λ = 405 nm λ = 420 nm λ = 455 nm

Example 4 B: Free radical photopolymerization of the acrylate monomer TMPTA

The next step was testing the suitability of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives for the role of photosensitizers of commercially available iodonium salts to monitor the course of radical photopolymerization of the acrylate monomer TMPTA. The study was performed for two-component systems consisting of Speedcure® 938 iodonium salt (concentration 1%) and photosensitizers (concentration (0.1%). FT-

IR spectra before and after photopolymerization of the TMPTA monomer are shown in Fig. 13 and Fig. 14.

Then, using the data obtained, double bond conversions were calculated for compositions containing specific initiator systems based on iodonium salt and a photosensitizer in the form of the corresponding 2-(diethylamino)- 4,6-diphenylbenzene-1,3-carbonitrile derivatives. The data are presented in the Fig. 15 - Fig. 20.

The studies showed that during the radical photopolymerization of the acrylate monomer TMPTA, all the 2-

(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives studied are useful for the role of highly effective photosensitizers in the two-component initiator system. The study was carried out using visible light sources emitting radiation at λ = 405nm, λ = 420 nm and λ = 455 nm.

Table 6. Comparison of the efficiency of initiation of radical photopolymerization for TMPTA acrylic monomer with the participation of a photoinitiating system composed of diaryliodonium salt (1%wt. ) and the tested 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives as photosensitizers (0.1%wt.) under visible light (Vis) irradiation at λ = 405 nm, λ = 420 nm and λ = 455 nm.

Example 4C: Free radical photopolymerization of TMPTA acrylate monomer in the presence of two- component initiator systems (terphenyl/amine), (terphenyl/iodonium salt), and in the presence of three- component initiator systems (terphenyl/amine/iodonium salt)

The next step was to study the suitability of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives as components of photoinitiating systems for the radical photopolymerization of the acrylate monomer TMPTA in the presence of an iodonium salt and an amine, as well as a comparison of three-component systems with two- component systems. The studies were performed for systems consisting of Speedcure® 938 iodonium salt (concentration of 1%), photocatalysts (concentration (0.5%) and EDB amine (1.5%). The results were compared with bimolecular systems consisting of Speedcure® 938 iodonium salt (1% concentration) and photocatalysts (concentration (0.5%) and EDB amine (1.5%) and photocatalysts (concentration (0.5%). Photopolymemrization profiles are presented in Fig. 21 - Fig. 28, final conversion values are summarized in Table 7.

Table 7. Comparison of the efficiency of initiation of radical photopolymerization for TMPTA acrylic monomer with the participation of a photoinitiating system composed of diaryliodonium salt (1%wt.), studied 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives as photosensitizers (0.5%wt.) and EDB amine (1.5%) under visible light (Vis) irradiation at λ = 405 nm, λ = 420 nm and λ = 455 nm.

Example 4 D: Hybrid photopolymerization, which consists of the processes of simultaneously occurring radical photopolymerization of an acrylate monomer and cationic photopolymerization with opening of the epoxy ring The final step in the kinetic study of the suitability of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives for the role of photosensitizers of iodonium salts was to monitor the course of the hybrid photopolymerization of CADE and TMPTA monomers constituting a 70/30%wt photopolymerizing composition. The study was performed for binary photoinitiating systems composed of diaryl iodonium salt (1%wt.) and tested 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives as photosensitizers (0.1 %wt.) under irradiation with visible (Vis) light at λ = 405 nm, λ = 420 nm and λ = 455 nm.

Table 8. Comparison of the efficiency of initiation of hybrid photopolymerization consisting of the processes of simultaneous radical photopolymerization of acrylate monomer and cationic photopolymerization with photoinitiating system consisting of diaryliodonium salt (1%wt.) and the investigated 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives as photosensitizers (0.1 %wt.) under irradiation with visible light (Vis) at λ = 405 nm, λ = 420 nm and λ = 455 nm

The study showed that during hybrid photopolymerization, all studied 2-(diethylamino)-4,6-diphenylbenzene-1,3- carbonitrile derivatives are useful for the role of highly effective photosensitizers in the two-component initiating systems. The experiments were carried out using visible light sources emitting radiation at λ = 405 nm, λ = 420 nm and λ = 455 nm (Table 8).

Example 5. Use of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives in initiating systems for resins used in 3D printing.

3D printing experiments were conducted using a NEJE DK-8-KZ 1000 mW laser printer with a 405 nm laser diode with an intensity of 100 mW-cm-2. The prepared compositions were applied to a microscope slide with a rectangular mold and photopolymerization was carried out in air. Compositions consisting of the corresponding 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivative and Speedcure® 938 iodonium salt were applied during printing from TMPTA acrylate monomer, CADE epoxy monomer and TMPTA/CADE monomer mixture (3:7). The compositions consisted of 1 gram of monomer (in the case of hybrid photopolymerization, a total of 1g of monomers was added), Speedcure® 938 commercial photoinitiator in the amount of 10 mg, which accounted for 1% by weight, and 1 mg of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivative, which accounted for 0.1% by weight of the total composition (which was 3.68·10 ^-3 mol·dm ^-3 , respectively). The obtained prints for CADE monomer showed better quality than prints from the radical composition (based on TMPTA monomer), which was due to the slower progress of the process and the lack of oxygen inhibition during the cationic photopolymerization process. Next, systems with two monomers were used for SLA 3D printing: epoxy monomer CADE and acrylate monomer TMPTA. The initiator system consisted of Speedcure® 938 iodonium salt and the 2- (diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivative. The quality of the prints was good, but the print thickness was low. Prints were obtained in a very short time (about 1 min). The prints from the hybrid compositions obtained during the study had the highest resolution. The obtained samples were subjected to microscopic analysis.

Example 6. Controlled radical polymerization (CRP), 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives as photocatalysts initiating photoinduced atom transfer radical polymerization (photo-ATRP) processes

Atom transfer radical polymerization (photo ATRP) of methyl methacrylate (MMA) was carried out in the presence of EBPA alkyl bromide a-bromophenyl ethyl acetate (0.062 mmol, 1 eq) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivative catalyst (0,006 mmol, 0.1eq) in an inert gas (argon) atmosphere. The composition sealed in a vial was irradiated with LED@405nm (intensity of about 54.2 mWcm-2) for 4 hours. Molecular masses and dispersity were determined by GPC gel chromatography. A GPC system was used, a Shimadzu chromatograph equipped with an LC-20AD pump, a DGU-20A3R degasser, a 25 ml manual valve loop, a CTO-10AS VP thermostat, a set of 2 Phenogel columns and an RID-10A linear detector; tetrahydrofuran was used as the eluent.

Table 9. Data for photo-ATRP processes in the presence of 2-(diethylamino)-4,6-diphenylbenzene-1,3-cait>onitrile Brief Description of the Drawings

Fig. 1 Absorption spectra of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives in acetonitrile - part I.

Fig. 2 Absorption spectra of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives in acetonitrile - part II.

Fig. 3 Fluorescence spectra of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives in acetonitrile upon excitation 320 nm, with an integration time of 3000 ms.

Fig. 4 Fluorescence spectra of 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives in acetonitrile upon excitation 320 nm, with an integration time of 3000 ms.

Fig. 5 Changes in the FT-IR spectrum of the CADE epoxy monomer-based composition before and after the cationic photopolymerization process under 455 nm Vis-LED irradiation, using initiating system composed of diaryliodonium salt (1 %wt) and PK05-171 (0.1%wt).

Fig. 6 Changes in the FT-IR spectrum for the CADE epoxy monomer-based composition before and after the cationic photopolymerization process under 405 nm Vis-LED irradiation, using initiating system composed of diaryliodonium salt (1 %wt.) and PK05-171 (0.1%wt).

Fig. 7 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 405 nm - part l.

Fig. 8 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 405 nm - part II.

Fig. 9 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 420 nm - part l.

Fig. 10 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 420 nm - part II.

Fig. 11 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 455 nm - part I.

Fig. 12 Kinetic profiles showing the course of cationic photopolymerization of epoxy monomer in the presence of initiating system based on diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives under LED 455 nm - part II.

Fig. 13. Changes in FT-IR spectrum for TMPTA acrylate monomer-based composition before and after radical photopolymerization under 405 nm Vis-LED irradiation, using initiating system consisting of diaryliodonium salt (1 %wt.) and PK05-166 (0.1%wt.).

Fig. 14. Changes in FT-IR spectrum for TMPTA acrylate monomer-based composition before and after cationic photopolymerization under 405 nm Vis-LED irradiation, using initiating system consisting of diaryliodonium salt (1 %wt.) and PK05-171 (0.1 %wt ).

Fig. 15 Kinetic profiles showing the free radical photopolymerization of acrylate monomer in the presence of initiating system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 1) under LED 405 nm - part I.

Fig. 16 Selected kinetic profiles showing the course of radical photopolymerization of TMPTA acrylate monomer for an initiator system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 2) at 405 nm - part II.

Fig. 17 Kinetic profiles showing the free radical photopolymerization of acrylate monomer in the presence of initiating system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 1) under LED 420 nm - part I.

Fig. 18 Selected kinetic profiles showing the course of radical photopolymerization of TMPTA acrylate monomer for an initiator system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 2) at 420 nm - part II.

Fig. 19 Kinetic profiles showing the free radical photopolymerization of acrylate monomer in the presence of initiating system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 1) under LED 455 nm - part I.

Fig. 20 Selected kinetic profiles showing the course of radical photopolymerization of TMPTA acrylate monomer for an initiator system consisting of diaryliodonium salt and 2-(diethylamino)-4,6-diphenylbenzene-1,3-carbonitrile derivatives (series 2) at 455 nm - part II. Fig. 21 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiating systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK08-001, (b) PK05-163, (c) PK05-166 at 405 nm.

Fig. 22 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiating systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-167, (b) PK05-170, (c) PK05-172 at 405 nm.

Fig. 23 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiator systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-161, (b) PK05-171, (c) PK08-002 at 405 nm.

Fig. 24 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiator systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-187, (b) PK02-120 at 405 nm.

Fig. 25 Kinetic profiles showing the progress of free radical photopolymerization of TMPTA acrylate monomer for two- and three-component initiator systems composed of diaryliodonium salt (IOD), amine (EDB), and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK08-001, (b) PK05-163, (c) PK05-166 at 420 nm.

Fig. 26 Kinetic profiles showing the progress of free radical photopolymerization of TMPTA acrylate monomer for two- and three-component initiator systems composed of diaryliodonium salt (IOD), amine (EDB), and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-167, (b) PK05-170, (c) PK05-172 at 420 nm.

Fig. 27 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiator systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-161, (b) PK05-171, (c) PK08-002 at 420 nm.

Fig. 28 Kinetic profiles showing the progress of radical photopolymerization of TMPTA acrylate monomer for two- and three- component initiator systems composed of diaryliodonium salt (IOD), amine (EDB) and 2-(diethylamino)-4,6- diphenylbenzene-1,3-carbonitrile derivatives (a) PK05-187, (b) PK02-120 at 420 nm.