Photochemical anti-syn isomerization around the -N-N[double bond, length as m-dash] bond in heterocyclic imines.

ABSTRACT: EPR and NMR experiments on a quinazolinone-based Schiff's base in DMSO solution showed that irradiation with UV light (365 nm) leads to photochemically-induced isomerization from the anti- to the higher-energy syn-form around the -N-N[double bond, length as m-dash] linkage. The anti- to syn-isomerization was relatively fast, and the maximum amount of conversion detected (25%) was reached within 10 min; thermodynamic equilibrium re-established itself in about 15 min. DFT calculations were performed on the investigated compound and small model systems, and reproduced the experimental fact of the anti-conformer being lower in energy than the syn. Theoretical analysis of excited states, including visualisation of natural transition orbitals, identified

SUBMITTER: Hricovini M 

PROVIDER: S-EPMC9049245 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature