321733-39-5Relevant academic research and scientific papers
Coordination control of intramolecular electron transfer in boronate-bridged zinc porphyrin - Diimide molecules
Shiratori,Ohno,Nozaki,Yamazaki,Nishimura,Osuka
, p. 8747 - 8757 (2007/10/03)
Three sets of dyads, in which a zinc-porphyrin (ZP) electron donor is connected to an aromatic diimide electron accepter, 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 accepters 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 1ZP* 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.
