Polymerizations miscellaneous cationic

Complex cations containing 2,2 -bipyridyl or 1,10-phenanthroline as ligands, particularly those of ruthenium, have been encountered in Section 57.3.2.2(iii). However, the bis-chelate complex was generally anchored to a polymer chain by coordination to pendant pyridyl groups although the possibility of electrochemical polymerization of a 4-vinyl-4-methyl-2,2 -bipyridyl was considered.59 In this section, some miscellaneous examples of the role of bipyridyl and phenanthroline complexes are considered. 

A large number of cationic photoinitiators are known. The most significant from the commercial point of view are aryldiazonium, diaryliodon-ium, triarylsulfonium, and ferrocenium salts. These salts possess anions of very low nucleophilicity which do not terminate the polymerization process. Nonionic cationic photoinitiators such as organosilanes, latent sulfonic acids, and some other miscellaneous compounds are also used. 

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