Acylphosphineoxide initiators

An acyl phosphine oxide initiator comprising an acyl group selected from the group consisting of a benzoyl group substituted in position 3 by either a urea group or an oxalylamide group;

• a 2,6-dimethyl benzoyl group substituted in position 3 by either a urea group or an oxalylamide group;
• a 2,6-dimethoxy benzoyl group substituted in position 3 by either a urea group or an oxalylamide group;
• a 2,4,6-trimethyl benzoyl group substituted in position 3 by either a urea group or an oxalylamide group;
• and a 2,4,6-trimethoxybenzoyl group substituted in position 3 by either a urea group or an oxalylamide group,
• wherein if the acyl group comprises a urea group, then the acyl phosphine oxide initiator does not comprise a thiol group, and
• wherein the acyl phosphine oxide initiator is of Formula (III):
• wherein
• each R2 is selected from the group consisting of a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and OR8;
• and
• each R3 is selected from the group consisting of a substituted and substituted aryl group, a substituted or unsubstituted heteroaryl group, or is of Formula (II);
• wherein
• * is the point of attachment to the phosphine oxide group in Formula (III);
• each R4, R5 and R6 independently is hydrogen, methyl, or methoxy;
• each R7 and R8 independently is hydrogen, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted heteroaryl group, a (meth)acrylate containing group, or a (meth)acrylamide containing group;
• L is a divalent linking group comprising 2 to 60 carbon atoms;
• and
• n is an integer having a value of 0 or 1.