Unprecedented Bifunctional Chemistry of Bis(acyl)phosphane Oxides in Aqueous and Alcoholic Media

Max Schmallegger, Anna Eibel, Jan P. Menzel, Anne Marie Kelterer, Michal Zalibera, Christopher Barner-Kowollik, Hansjörg Grützmacher, Georg Gescheidt*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Tailor-made photoinitiators play an important role for efficient radical polymerisations in aqueous media, especially in hydrogel manufacturing. Bis(acyl)phosphane oxides (BAPOs) are among the most active initiators. Herein, we show that they display a remarkable photochemistry in aqueous and alcoholic media: Photolysis of BAPOs in the presence of water or alcohols provides a new delocalized π-radical, which does not participate in the polymerization. It either converts into a monoacylphosphane oxide acting as a secondary photoactive species or it works as a one-electron reducing agent. Upon the electron-transfer process, it again produces a dormant photoinitiator. We have established the structure and the chemistry of this π radical using steady-state and time-resolved (CIDEP) EPR together with ESI-MS, NMR spectroscopy, and DFT calculations. Our results show that bis(acyl)phosphane oxides act as bifunctional reagents when applied in aqueous and alcoholic media.

Original languageEnglish
Pages (from-to)8982-8986
Number of pages5
JournalChemistry - a European Journal
Volume25
Issue number38
DOIs
Publication statusPublished - 5 Jul 2019

Keywords

  • BAPOs
  • density functional calculations
  • ESI-MS
  • NMR spectroscopy
  • photochemistry

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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