Accurate Prediction of the Excited States in the Fully Conjugated Porphyrin Tapes across the Full Spectral Range: A Story of the Interplay between π-π* and Intramolecular Charge-Transfer Transitions in Soft Chromophores

Rodion V Belosludov; Dustin E Nevonen; Victor N Nemykin

doi:10.1021/acs.jpca.1c00217

Accurate Prediction of the Excited States in the Fully Conjugated Porphyrin Tapes across the Full Spectral Range: A Story of the Interplay between π-π* and Intramolecular Charge-Transfer Transitions in Soft Chromophores

J Phys Chem A. 2021 Apr 1;125(12):2480-2491. doi: 10.1021/acs.jpca.1c00217. Epub 2021 Mar 18.

Authors

Rodion V Belosludov¹, Dustin E Nevonen², Victor N Nemykin^{2

3}

Affiliations

¹ Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
² Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
³ Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States.

PMID: 33734683
DOI: 10.1021/acs.jpca.1c00217

Abstract

The ability of density functional theory (DFT) and time-dependent DFT (TDDFT) methods for the accurate prediction of the energies and oscillator strengths of the excited states in a series of fully conjugated meso-meso β-β β-β triple-linked porphyrin oligomers (porphyrin tapes 2-12) was probed in the gas phase and solution using several exchange-correlation functionals. It was demonstrated that the use of the hybrid B3LYP functional provides a good compromise for the accurate prediction of the localized π-π* and intramolecular charge-transfer transitions, thus allowing confident interpretation of the UV-vis-NIR spectra of porphyrin oligomers. The TDDFT-based sum-over-state (SOS) calculations for the porphyrin tape dimer 2 and trimer 3 as well as parent monomer 1 correctly predicted the signs and shapes of the magnetic circular dichroism (MCD) signals in the low-energy region of the spectra.