Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Articles
Dioxygen Binding to a Cobalt(II) Porphycene Complex and Its Auto-Oxidized Cobalt(III) Complex
Hisashi ShimakoshiIsao AritomeShun HirotaYoshio Hisaeda
Author information
JOURNALS RESTRICTED ACCESS

2005 Volume 78 Issue 9 Pages 1619-1623

Details
Abstract

The reaction between a cobalt porphycene complex, [CoII(TPrPc)] (TPrPc is a dianion of 2,7,12,17-tetrapropylporphycene), and dioxygen was investigated by means of UV–vis, ESR, and resonance Raman (RR) spectroscopies. These spectra indicate the formation of [CoIII–O2−•]. In the presence of pyridine as an axial ligand, the formation of a six-coordinated superoxide species was confirmed by its characteristic ESR spectrum. The six-coordinated dioxygen adduct exhibits an RR band at 1144 cm−1, which is characteristic of O–O stretching of superoxide. ν(Co–O2) stretching is also observed at 540 cm−1. The ν(O–O) and ν(Co–O2) wavenumbers in the complex were assigned by means of 18O2 substitution. ν(Co–O2) of the O2 adduct shows a higher frequency relative to those of cobalt porphyrin complexes. On standing for one day at room temperature, the compound was auto-oxidized to a CoIII complex, which was structurally determined by X-ray analysis. The complex crystallized in the monoclinic space group P21/n, a = 9.6266(4) Å, b = 12.6343(5) Å, c = 15.6566(6) Å, β = 99.1200(10)°, V = 1880.17(13) Å3, and Z = 2. The CoIII ion lies on the plane of the porphycenato core, and coordinates four porphycenato nitrogen atoms and two pyridine nitrogen atoms. The complex cation, [CoIII(TPrPc)(Py)2]+, exhibits a slightly distorted octahedral coordination geometry. The average Co–N (porphycenato pyrrole) distance and the Co–N (pyridine) distance are 1.929 and 1.952 Å, respectively.

Information related to the author

This article cannot obtain the latest cited-by information.

© 2005 The Chemical Society of Japan
Previous article Next article
feedback
Top