Urs K Fischer
Ivoclar Vivadent AG, Liechtenstein
Title: Photoinitiating efficiency of visible light initiators based on tetraacyl derivatives of germanium and tin
Biography
Biography: Urs K Fischer
Abstract
For several years, bisacylgermanium derivatives have been known to be very potent monomolecular initiators for photopolymerization induced by visible light (VL).[1] In particular, bis-(4-methoxybenzoyl) diethylgermane (Ivocerin®) exhibits an outstanding performance as amine-free Norrish type I photoinitiator (PI) for polymerization of dimethacrylate resins in dental materials and dimethacrylate-based composites, initialized by blue LED curing lights. Ivocerin® is characterized by strong absorption in the blue region of the VL spectrum, good solubility in and high PI reactivity towards dimethacrylate resins, good storage stability and excellent bleaching behavior. Recently, a very efficient synthetic method was developed, which allows the preparation of tetraacylgermanium derivatives according to a facile procedure in good yields. Based on the same synthetic procedure, the tin analogue tetrakis (2, 4, 6-trimethylbenzoyl) stannane is accessible, which displays a significant VL absorption beyond 500 nm.
