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Updated: Aug 13, 2026

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Coordination control of intramolecular electron transfer in boronate-bridged zinc porphyrin-diimide molecules
H Shiratori1, T Ohno, K Nozaki
1Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Abstract:
Three sets of dyads, in which a zinc-porphyrin (ZP) electron donor is connected to an aromatic diimide electron acceptor,either pyromellitimide (PI) or naphthalene-1,8:4,5-tetracarboxylic acid diimide (NI), via a boronate-ester bridge, a piperidine bridge, and a 1,3-dioxolane bridge, respectively, were prepared for the purpose of control of intramolecular electron transfer (ET) by acid-base reactions at the connecting bridge. Boronate-ester bridge is a Lewis acidic site and confers a chance to regulate intramolecular ET reaction upon base coordination. This has been demonstrated by suppression of photoinduced ET from ZP to PI or NI in highly electron-pair donating solvents or upon addition of a fluoride anion. To extend this strategy to control of ET-path selectivity, we prepared triad 18, which consists of a ZP donor bearing NI and PI acceptors at similar distances through a boronate-ester bridge and an acetal bridge, respectively. Photoexcitation of 18 in a free form led to intramolecular ET from (1)()ZP preferentially to NI, but the ET path was completely switched toward PI in F(-)-coordinated form without a serious drop in the rate, constituting a novel ET-switching molecular system.
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