UV-Induced Benzyloxy Rotamerization in an Ortho OH-Substituted Aryl Schiff Base

Sidir I., Sidir Y. G., Gobi S., Berber H., Fausto R.

PHOTOCHEM, no.2, pp.376-389, 2022 (ESCI) identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.3390/photochem2020026
  • Journal Name: PHOTOCHEM
  • Journal Indexes: Emerging Sources Citation Index (ESCI)
  • Page Numbers: pp.376-389
  • Istanbul Kültür University Affiliated: Yes

Abstract

A new benzyloxy containing ortho hydroxyl-substituted aryl Schiff base, trans 2-((2-(benzyloxy)benzylidene) amino)phenol (abbreviated as BBAP), was synthesized and characterized by H-1-, C-13-NMR and infrared spectroscopic techniques and elemental analysis. The conformational landscape of the compound, as well as its infrared spectra in argon and N-2 cryogenic matrices (10 K) were investigated, followed by the study of the effects of in situ UV irradiation of the matrix-isolated compound. The structural information was obtained through an extensive series of quantum chemical calculations performed at the DFT(B3LYP)/6-311++G(d,p) level of theory, which enabled to identify 3 low-energy OHN intramolecularly H-bonded conformers of the molecule that were later found to be present in the as-deposited cryogenic matrices. The 3 experimentally relevant conformers of BBAP differ in the geometry of the benzyloxy substituent, and were discovered to interconvert upon in situ UV irradiation (lambda = 230 nm) of the matrix-isolated compound. This is the first report on UV-induced conformational changes taking place in a benzyloxy fragment for a matrix-isolated compound.