title: Porphyrinylboranes Synthesized via Porphyrinyllithiums.
abstract: As the most nucleophilic porphyrins, meso- or β-lithiated porphyrins were generated by iodine-lithium exchange reactions of the corresponding iodoporphyrins with n-butyllithium at -98 °C. Porphyrinyllithiums thus prepared were used for synthesis of dimesitylporphyrinylboranes through reactions with fluorodimesitylborane. The boryl groups proved to serve as an electron-accepting unit to alter the photophysical and electrochemical properties. In addition, 5-diarylamino-15-dimesitylboryl-substituted donor-accepter porphyrins showed increased intramolecular charge-transfer character in the S1 state. Furthermore, the reaction of β-lithiated porphyrin with dichloromesitylborane provided a boron-bridged porphyrin dimer, which exhibited a conjugative interaction between two porphyrin units through the vacant p-orbital on the boron center.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku Kyoto 606-8502 (Japan).
authors.forename: Keisuke
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku Kyoto 606-8502 (Japan). yori@kuchem.kyoto-u.ac.jp.|ACT-C Japan Science and Technology Agency, Sakyo-ku Kyoto 606-8502 (Japan). yori@kuchem.kyoto-u.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yorimitsu
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku Kyoto 606-8502 (Japan). osuka@kuchem.kyoto-u.ac.jp.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Osuka
keywords: borylation; donor-acceptor systems; halogen-lithium exchange; porphyrin; triarylborane