On the photolysis of acylphosphine oxides: 1. Laser flash photolysis studies with 2,4,6-trimethylbenzoyldiphenylphosphine oxide

A Novel Approach for Measuring Absolute Rate Constants by Pulsed Electron Spin Resonance: Addition of Phosphinoyl and 2-Hydroxy-2-propyl Radicals to Several Alkenes,

“…30, 35 The photochemistry and photophysics of bis(acyl)phosphine oxides (2 and 3) are similar to those of the mono(acyl)phosphine oxides (1) and are fairly well understood. 30,79,[86][87][88][89][90] After excitation with light, photoinitiators 2 and 3 undergo an efficient R-cleavage from the excited triplet state to produce strongly spin-polarized acylphosphinoyl (2a, 3a) and benzoyl (2b, 3b) radicals:…”

Synthesis of a novel camphorquinone derivative having acylphosphine oxide group, characterization by UV-VIS spectroscopy and evaluation of photopolymerization performance

“…Since the absorption coefficient of CQ-APO (26.0 M -1 cm -1 ) was approximately the same as that of TMDPO after light irradiation, it could be understood that the C-P cleavage of [>P(=O)-C(=O)-] bond at around 380 nm was generated in both CQ-APO and TMDPO. This occurred via an α-cleavage type of photoinitiation mechanism (Norrish type I system) 4,5) upon light irradiation. Unlike α-cleavage type, in the case of CQ, slow hydrogen abstraction from a solvent toluene does not lead to considerable reduction in an absorption coefficient.…”

“…APO and BAPO undergo so-called α-cleavage type photoinitiation mechanisms (Norrish type I systems) 4,5) in which APO undergoes homolytic α-cleavage at the C-P bond to generate two free-radical species, namely [-(O=)C • ] and [ • P(=O)<]. Both free-radical species are capable of initiating the polymerization, although with different rate constants 4,5) .…”

“…Both free-radical species are capable of initiating the polymerization, although with different rate constants 4,5) . Unlike CQ/tertiary amine system, APO does not require accelerators such as tertiary amines, which might cause adverse interaction with acidic adhesive monomers 2,6) .…”

Light-curing of dental resins with GaN violet laser diode: The effect of photoinitiator on mechanical strength

“…These initiators help reduce the intensity of the yellow tint and improve the photopolymerization efficiency [2,3]. The optimal absorbance wavelengths are mostly distributed from the ultraviolet (UV) to violet visible light region; hence, photopolymerization is barely initiated by standard QTH-LCUs, and might not be initiated at all by blue LED-LCUs [4].…”