Photoinitiators and curable compositions

A photoinitiator comprising:

• a photoinitiator according to Formula (I):
• wherein
• R1 is selected from the group consisting of an alkyl group, an aryl group, a heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, R5—O—, R6—S—, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, a benzophenone group, an a-hydroxyketone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group;
• R2 is selected from the group consisting of hydrogen, an alkyl group, an aryl group, a heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, and an aralkyl group;
• R3 is selected from the group consisting of —C(═O)—O—R7, —C(═O)—NR8—R9, —C(═O)—R7, hydrogen, an alkyl group, an aryl group, a heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, a benzophenone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group;
• R4 is selected from the group consisting of —C(═O)—O—R10, —C(═O)—NR11—R12, —C(═O)—R10, a nitrile group, an aryl group, a heteroaryl group, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group;
• R5 and R6 are independently selected from the group consisting of an alkyl group, an aryl or heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, a benzophenone group, an α-hydroxyketone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group;
• and
• R7, R8, R9, R11 and R12 are independently selected from the group consisting of hydrogen, an alkyl group, an aryl or heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, a benzophenone group, an α-hydroxyketone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group, with the proviso that R8 and R9 and/or R11 and R12 may also represent atoms necessary to form a five or six membered ring;
• R10 is selected from the group consisting of hydrogen, an alkyl group, an aryl or heteroaryl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, and a photoinitiating moiety selected from the group consisting of a thioxanthone group, an α-hydroxyketone group, an α-aminoketone group, an acylphosphine oxide group, and a phenyl glyoxalic acid ester group;
• and at least one of R1, R3, and R4 is functionalized with the photoinitiating moiety;
• or
• a photoinitiator selected from group consisting of: