title: Synthesis, characterization, and electrochemistry of the manganese(I) complexes of meso-substituted [14]tribenzotriphyrins(2.1.1).
abstract: Metalation of 6,13,20,21-tetraaryl-22H-[14]tribenzotriphyrins(2.1.1) (TriP, 1 a-d) with [Mn(CO)5 Br] provided Mn(I) tricarbonyl complexes of [14]tribenzotriphyrins(2.1.1) 2 a-d in 85-93 % yield. The complexes were characterized by mass spectrometry and UV/Vis absorption, IR, and NMR spectroscopy. Single-crystal X-ray analyses revealed that 2 b and 2 c adopt bowl-shaped conformations. The redox properties of [(TriP)Mn(I) (CO)3 ] (2 a-d) were studied by cyclic voltammetry. Each compound undergoes two reversible one-electron reductions to form a porphyrin π anion radical and a dianion in CH2 Cl2 . Two oxidation waves were observed, the first of which corresponds to a metal-centered electron-transfer process. The redox potentials of 2 a-d are consistent with the optical spectroscopic data and the relatively narrow HOMO-LUMO gaps that were predicted in DFT calculations. The optical spectra can be assigned by using Michl's perimeter model. TDDFT calculations predict the presence of several metal-to-ligand charge-transfer bands in the L-band region between 500 and 700 nm.
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu University, Xuefu Road 301, Zhenjiang 212013 (P. R. China).
authors.forename: Zhaoli
authors.initials: Z
authors.lastname: Xue
authors.forename: Yemei
authors.initials: Y
authors.lastname: Wang
authors.forename: John
authors.initials: J
authors.lastname: Mack
authors.forename: Weihua
authors.initials: W
authors.lastname: Zhu
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Ou
keywords: circular dichroism; density functional calculations; electrochemistry; manganese; porphyrinoids