Arylsulfinate salts in photoinitiator systems for polymerization reactions

A composition comprising:

• an electron donor comprising an arylsulfinate salt having a anion of Formula I
• Ar1—SO231 I
• and a cation having at least one carbon atom and either a positively charged nitrogen atom or a positively charged phosphorus atom, said electron donor having an oxidation potential in N,N-dimethylformamide of 0.0 to +0.4 volts versus a silver/silver nitrate reference electrode, wherein
• Ar1 is a substituted phenyl, an unsubstituted or substituted C7-30 aryl, or an unsubstituted or substituted C3-30 heteroaryl, said substituted Ar1 having a substituent that is an electron withdrawing group or an electron withdrawing group in combination with an electron donating group
• the cation is selected from
• 1) a phosphorous-containing cation of Formula III
• where each R2 is independently an unsubstituted alkyl, an alkyl substituted with a hydroxy, an unsubstituted aryl, or an aryl substituted with an ethyl, hydroxy, or combinations thereof;
• or
• 2) a nitrogen-containing cation having a ring structure comprising a 4 to 12 member heterocyclic group having a positively charged nitrogen atom, said heterocyclic being saturated or unsaturated and having up to 3 heteroatoms selected from oxygen, sulfur, nitrogen, or combinations thereof, wherein said ring structure is unsubstituted or substituted with a substituent selected from an alkyl, aryl, acyl, alkoxy, aryloxy, halo, mercapto, amino, hydroxy, azo, cyano, carboxy, alkoxycarbonyl, aryloxycarbonyl, halocarbonyl, or combinations thereof;
• and
• a sensitizing compound capable of absorbing a wavelength of actinic radiation in the range of 250 to 1000 nanometer, the sensitizing compound comprising a dye selected from a ketone, xanthene, acridine, thiazole, thiazine, oxazine, azine, aminoketone, aromatic polycyclic hydrocarbon, p-substituted aminostyryl ketone, aminotriaryl methane, cyanine, pyridinium, or triarylmethane.