title: Group 14 Dithienometallole-Linked Ethynylene-Conjugated Porphyrin Dimers.
abstract: The considerably conjugated π systems of the group 14 dithienometallole-linked ethynylene-conjugated porphyrin dimers (1Ms) were described based on comprehensive experimental and theoretical studies. The electronic absorption spectra of 1M displayed a large splitting in the Soret band and a red-shifted Q-band, indicating that the dithienometallole spacer was effective in facilitating the porphyrin-porphyrin electronic coupling. Torsional planarization behaviors of 1M were observed in the time-resolved fluorescence spectra. Density functional theory (DFT) calculations revealed that the dithienometallole spacer is an ideal partner for the ethynylene-conjugated porphyrin to produce fully delocalized highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels due to their similar HOMO and LUMO levels. Finally, 1M exhibited a strong propensity for the quinoidal-cummulenic conjugation in the dithienometallole spacer when in a photoexcited state.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Morisue
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hoshino
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University , Higashi-Hiroshima 739-8527, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Yumura
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Machida
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University , Higashi-Hiroshima 739-8527, Japan.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Ooyama
authors.forename: Masaki
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University , Higashi-Hiroshima 739-8527, Japan.
authors.forename: Joji
authors.initials: J
authors.lastname: Ohshita