Phenacyl cationic photoinitiators

Recently, Yagci and coworkers investigated the initiation mechanism of a new type of cationic photoinitiator, namely, /V-phenacyl-/V,/V-dimethylanilinium hexafluoroan-timonate (PDA+ Sbl fi ) which initiates the polymerization of appropriate monomers [116]. The proposed mechanism includes irreversible fragmentation of the absorbent salt to yield the initiating species either via a heterolytic cleavage or via a homolytic cleavage followed by subsequent electron transfer between the preformed species still, forming the same cation that initiates cationic polymerization (Scheme 11.30). 

F. Kasapoglu, et al., Photoinitiated cationic polymerization using a novel phenacyl anilinium salt. Polymer 2002, 43(8), 2575-2579. 

N. Yonet, N. Bicak, and Y. Yagci, Photoinitiated cationic polymerization of cyclohexene oxide by using phenacyl benzoylpyridinium salts. Macromolecules 2006, 39(8), 2736-2738. 

Nitrogen, XII, and phosphorus, XIII, analogs to the already described dialkyl-pheriacylsulfonium salts have also been reported to be active photoinitiators for the cationic polymerization of many different types of monomers Their synthesis can be achieved by the direct condensation of phenacyl halides with the appropriate amine or phosphine. 

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