Are multicentre bond indices and related quantities reliable predictors of excited-state aromaticity?

Ponec, Robert, Cooper, David L ORCID: 0000-0003-0639-0794 and Karadakov, Peter B (2020) Are multicentre bond indices and related quantities reliable predictors of excited-state aromaticity? Molecules.

There is a more recent version of this item available.

Text
molecules-949153.pdf - Author Accepted Manuscript
Access to this file is restricted: awaiting official publication and publisher embargo.
Download (534kB)

Abstract

Systematic scrutiny is carried out of the ability of multicentre bond indices and the NOEL-based similarity index dAB to serve as excited-state aromaticity criteria. These indices were calculated using state-optimized complete active-space self-consistent field wavefunctions for several low-lying singlet and triplet states of the paradigmatic molecules of benzene and cyclobutadiene and the inorganic ring S₂N₂. The comparison of the excited-state indices with aromaticity trends for individual excited states suggested by the values of magnetic aromaticity criteria show that whereas the indices work well for aromaticity reversals between the ground singlet and first triplet electronic states, addressed by Baird’s rule, there are no straightforward parallels between the two sets of data for singlet excited states. The problems experienced while applying multicentre bond indices and dAB to singlet excited states are explained by the loss of the information inherently present in wavefunctions and/or pair densities when calculating the first-order density matrix.

Item Type:	Article
Uncontrolled Keywords:	excited-state aromaticity reversals, multicentre bond indices, molecular similarity, magnetic properties of excited states
Depositing User:	Symplectic Admin
Date Deposited:	16 Oct 2020 07:24
Last Modified:	18 Jan 2023 23:28
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3104325