Formation of a long-lived electron-transfer state in mesoporous silica-alumina composites enhances photocatalytic oxygenation reactivity

Shunichi Fukuzumi, Kaoru Doi, Akinori Itoh, Tomoyoshi Suenobu, Kei Ohkubo, Yusuke Yamada, Kenneth D. Karlin

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

A simple donor-acceptor linked dyad, 9-mesityl-10-methylacridinium ion (Acr+-Mes) was incorporated into nanosized mesoporous silica-alumina to form a composite, which in acetonitrile is highly dispersed. In this medium, upon visible light irradiation, the formation of an extremely long-lived electron-transfer state (Acr-Mes•+) was confirmed by EPR and laser flash photolysis spectroscopic methods. The composite of Acr+-Mes-incorporated mesoporous silica-alumina with an added copper complex [(tmpa)CuII](ClO4-)2 (tmpa = tris(2-pyridylmethyl)amine) acts as an efficient and robust photocatalyst for the selective oxygenation of p-xylene by molecular oxygen to produce p-tolualdehyde and hydrogen peroxide. Thus, incorporation of Acr +-Mes into nanosized mesoporous silica-alumina combined with an O2-reduction catalyst ([(tmpa)CuII]2+) provides a promising method in the development of efficient and robust organic photocatalysts for substrate oxygenation by dioxygen, the ultimate environmentally benign oxidant.

Original languageEnglish
Pages (from-to)15572-15577
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number39
DOIs
StatePublished - 25 Sep 2012

Keywords

  • Copper complex catalyst
  • Donor-acceptor dyad
  • Nanosized silica-alumina
  • Photoinduced electron transfer
  • p-xylene

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