title: Optical, electrochemical, and magnetic properties of pyrrole- and thiophene-bridged 5,15-diazaporphyrin dimers.
abstract: The first examples of pyrrole- and thiophene-bridged 5,15-diazaporphyrin (DAP) dimers are prepared through Stille coupling reactions of nickel(II) and copper(II) complexes of 3-bromo-10,20-dimesityl-5,15-diazaporphyrin (mesityl=2,4,6-trimethylphenyl) with the respective 2,5-bis(tributylstannyl)heteroles. The effects of the heterole spacers and meso nitrogen atoms on the optical, electrochemical, and magnetic properties of the DAP dimers are investigated by UV/Vis absorption spectroscopy, density functional theory calculations, magnetic circular dichroism spectroscopy, cyclic voltammetry, and EPR spectroscopy. The heterole spacers are found to have a significant impact on the electronic transitions over the entire π-system. In particular, the pyrrole-bridged DAP dimers exhibit high light-harvesting potential in the low-energy visible/near-infrared region owing to the intrinsic charge-transfer character of the lowest excitation.
authors.affiliation: Department of Fundamental Sciences, Graduate School of Science and Technology, Niigata University, Nishi-ku, Niigata 950-2181 (Japan).
authors.forename: Satoshi
authors.initials: S
authors.lastname: Omomo
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Ko
authors.initials: K
authors.lastname: Furukawa
authors.forename: Taniyuki
authors.initials: T
authors.lastname: Furuyama
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Nakano
authors.forename: Nagao
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matano
mesh_terms: D004563:Electrochemistry / Q000379:methods*; D008280:Magnetics; D008958:Models, Molecular; D011758:Pyrroles / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D011758:Pyrroles; D013876:Thiophenes
keywords: EPR spectroscopy; diazaporphyrins; macrocyclic compounds; porphyrinoids; transition metals