Application of the Perimeter Model to the Assignment of the Electronic Absorption Spectra of Gold(III) Hexaphyrins with [4n 2] and [4n] pi-Electron Systems

作者：Muranaka Atsuya; Matsushita Osamu; Yoshida Kengo; Mori Shigeki; Suzuki Masaaki; Furuyama Taniyuki; Uchiyama Masanobu; Osuka Atsuhiro^*; Kobayashi Nagao

来源：Chemistry - A European Journal, 2009, 15(15): 3744-3751.

DOI：10.1002/chem.200801742

• ab initio calculations
• electronic structure
• magnetic properties
• porphyrinoids

The electronic excited states of two forms of meso-hexakis(pentafluorophenyl)-substituted gold(III) hexaphyrin(1.1.1.1.1.1) have been investigated by density functional calculations and magnetic circular dichroism (MCD) spectroscopy, in order to assign their low-energy excited singlet states. We found that the perimeter model can be successfully applied to the interpretation of the electronic states. In the case of the neutral forms (Au(2)-N, Au-N), the absorption bands observed in the NIR and visible region can be assigned to pi-pi* transitions referred to as the L and B bands, respectively, analogous to the Q and Soret bands of regular porphyrins. In marked contrast with the neutral forms, the absorption bands of the reduced forms (Au(2)-R and Au-R) are attributed to pi-pi* transitions involving six frontier molecular pi orbitals. By applying the 4N-electron perimeter model, the six orbitals are labeled as h(-), h( ), s(-), s( ), l(-), and l( ), while the observed absorption bands can be assigned to the S, N(1), N(2), P(1), and P(2) transitions, in order of increasing energy.

• 出版日期2009