Fourteen-Electron Ring Model and the Anomalous Magnetic Circular Dichroism of meso-Triarylsubporphyrins

作者:Vancoillie Steven; Hendrickx Marc; Minh Tho Nguyen; Pierloot Kristine; Ceulemans Arnout*; Mack John; Kobayashi Nagao
来源:Journal of Physical Chemistry A, 2012, 116(15): 3960-3967.
DOI:10.1021/jp302623q

摘要

The MCD spectra of meso-triarylsubporphyrins show a sign anomaly which is correlated with the acceptor properties of the aryl substituent. From the spectra, magnetic moments of the excited states are determined. In the context of a simplified orbital model, the sign change is attributed to the quenching of the magnetic moment of the LUMO by acceptor orbitals of the substituent. The actual calculation of this moment presents a major challenge to computational methods. It is shown that wave function techniques based on CASSCF underestimate the covalency effects that are responsible for the quenching. In contrast, a CI method based on DFT orbitals yields excellent results; which fully support the orbital model.

  • 出版日期2012-4-19