Multifrequency TREPR Investigation of Excited-State ZnTPP/Nitroxide Radical Complexes |
| |
Authors: | Valery F Tarasov Saiful S M Islam Yasunori Ohba Malcolm D E Forbes Seigo Yamauchi |
| |
Institution: | 1. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin St., 4, 119991, Moscow, Russia 3. Caudill Laboratories, Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, NC, 27599-3290, USA 2. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan
|
| |
Abstract: | Multiple-frequency (X-band and W-band) time-resolved electron paramagnetic resonance spectra of Zn-tetraphenylporphyrin (ZnTPP) triplet states coordinated to two different stable nitroxide moieties are presented and discussed. The position of the pyrimidyl nitroxide relative to the ZnTPP plane is the only structural change made between the two complexes, from ortho to para. This changes the angle between the interacting orbitals of the three-spin system with only a minor change in the distance between the unpaired electron of the nitroxide and the TPP ring system. Changes in the electron spin polarization patterns at the two different frequencies of observation are discussed in terms of a radical?Ctriplet pair spin-state mixing model, including the intersystem crossing processes. It is determined that the inclusion of an additional spin-selective relaxation process to the computational model for the spectral shapes gives adequate reproduction of the experimental results using the same parameters at each frequency. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|