1487465-75-7Relevant academic research and scientific papers
Acylgermanes: Photoinitiators and sources for Ge-centered radicals. insights into their reactivity
Neshchadin, Dmytro,Rosspeintner, Arnulf,Griesser, Markus,Lang, Bernhard,Mosquera-Vazquez, Sandra,Vauthey, Eric,Gorelik, Vitaly,Liska, Robert,Hametner, Christian,Ganster, Beate,Saf, Robert,Moszner, Norbert,Gescheidt, Georg
supporting information, p. 17314 - 17321 (2014/01/06)
Acylgermanes have been shown to act as efficient photoinitiators. In this investigation we show how dibenzoyldiethylgermane 1 reacts upon photoexcitation. Our real-time investigation utilizes femto- and nanosecond transient absorption, time-resolved EPR (50 ns), photo-chemically induced dynamic nuclear polarization, DFT calculations, and GC-MS analysis. The benzoyldiethylgermyl radical G? is formed via the triplet state of parent 1. On the nanosecond time scale this radical can recombine or undergo hydrogen-transfer reactions. Radical G? reacts with butyl acrylate at a rate of 1.2 ± 0.1 × 108 and 3.2 ± 0.2 × 108 M-1 s-1, in toluene and acetonitrile, respectively. This is ～1 order of magnitude faster than related phosphorus-based radicals. The initial germyl and benzoyl radicals undergo follow-up reactions leading to oligomers comprising Ge-O bonds. LC-NMR analysis of photocured mixtures containing 1 and the sterically hindered acrylate 3,3-dimethyl-2-methylenebutanoate reveals that the products formed in the course of a polymerization are consistent with the intermediates established at short time scales.
