Published In

The Journal of Physical Chemistry. A

Document Type

Article

Publication Date

10-29-2021

Subjects

Porphyrins -- Analysis, Porphyrins -- Synthesis

Abstract

A detailed TDDFT study (with all-electron STO-TZ2P basis sets and the COSMO solvation model) has been carried out on the effect of diprotonation on the UV-vis-NIR spectra of free-base tetraphenylporphyrin and tetrakis(-aminophenyl)porphyrin. The diprotonated forms have been modeled as their bis-formate complexes, i.e., as so-called porphyrin diacids. The dramatic redshift of the Q-band of the TAPP diacid has been explained in terms of an elevated "a" HOMO and lowered LUMOs, both reflecting infusion of aminophenyl character into the otherwise classic Gouterman-type frontier MOs. The exercise has also yielded valuable information on the performance of different exchange-correlation functionals. Thus, the hybrid B3LYP functional was found to yield a substantially better description of key spectral features, especially the diprotonation-induced redshifts, than the pure OLYP functional. Use of the range-separated CAMY-B3LYP functional, on the other hand, did not result in improvements relative to B3LYP.

Rights

© 2021 The Authors. Published by American Chemical Society

DOI

10.1021/acs.jpca.1c06621

Persistent Identifier

https://archives.pdx.edu/ds/psu/36638

Included in

Chemistry Commons

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