Acylstannanes: Cleavable and Highly Reactive Photoinitiators for Radical Photopolymerization at Wavelengths above 500 nm with Excellent Photobleaching Behavior

Abstract

Within this work, anovel acylstannane-based photoinitiator (PI) is presented. Tetrakis (2,4,6-trimethylbenzoyl) stannane (1) displays outstanding properties compared to state-of-the-art acylgermane-based initiators. Most importantly, the initiator shows absorption up to 550 nm, which allows higher penetration depths,especially in highly filled photopolymers. Besides that, 1 shows extremely high photo-initiating activity towards (meth)acrylic double bonds,aswell as very fast photobleaching.Furthermore,unlike many orga-notin compounds, 1 shows surprisingly low cytotoxicity.