title: Intramolecular triplet energy transfer in donor-acceptor molecules linked by a crown ether bridge.
abstract: Bichromophoric compounds BP-C-NP and BP-C-NBD were synthesized with benzophenone chromophore (BP) as the donor, and 2-naphthyl (NP) and norbornadiene group (NBD) as the acceptor, respectively. Their intramolecular triplet energy transfer was examined. The bridges linking the donor and acceptors in these molecules involve a crown ether moiety complexing a sodium ion. Phosphorescence quenching, flash photolysis and photosensitized isomerization experiments indicate that intramolecular triplet energy transfer occurs with rate constants of about 3.3 x 10(5) and 4.8 x 10(5) s(-1) and efficiencies of about 33 and 42 % for BP-C-NP and BP-C-NBD, respectively. Theoretical calculations indicate that these molecules adopt conformations below room temperature which allow their two-end chromophores conducive to through-space energy transfer.
authors.affiliation: Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, PR China.
authors.forename: Xiao-He
authors.initials: XH
authors.lastname: Xu
authors.forename: Xiao-Gang
authors.initials: XG
authors.lastname: Fu
authors.forename: Li-Zhu
authors.initials: LZ
authors.lastname: Wu
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Zhang
authors.forename: Chen-Ho
authors.initials: CH
authors.lastname: Tung
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Ji
authors.forename: Kirk S
authors.initials: KS
authors.lastname: Schanze
authors.forename: Rui-Qin
authors.initials: RQ
authors.lastname: Zhang