title: Quantum chemical exploration of the intramolecular hydrogen bond interaction in 2-thiazol-2-yl-phenol and 2-benzothiazol-2-yl-phenol in the context of excited-state intramolecular proton transfer: a focus on the covalency in hydrogen bond.
abstract: The present work demonstrates a computational exploration of the intramolecular H-bond (IMHB) interaction in two model heterocyclic compounds - 2-thiazol-2-yl-phenol (2T2YP) and 2-benzothiazol-2-yl-phenol (2B2YP) by meticulous application of various quantum chemical tools. Major emphasis is rendered on the analysis of IMHB interaction by calculation of electron density ρ(r) and Laplacian ∇(2)ρ(r) at the bond critical point using the Atoms-In-Molecule methodology. Topological features based on ρ(r) suggest that at equilibrium geometry the IMHB interaction develops certain characteristics typical of a covalent interaction. The interplay between aromaticity and Resonance-Assisted H-Bond (RAHB) has also been discussed using both geometrical and magnetic criteria. The occurrence of IMHB interaction in 2T2YP and 2B2YP has also been criticized under the provision of the Natural Bond Orbital (NBO) analysis. The ESIPT phenomenon in the molecular systems is also critically addressed on the lexicon of potential energy surface (PES) analysis.
authors.affiliation: Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009, India.
authors.forename: Bijan Kumar
authors.initials: BK
authors.lastname: Paul
authors.affiliation: Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009, India.
authors.forename: Aniruddha
authors.initials: A
authors.lastname: Ganguly
authors.affiliation: Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009, India. Electronic address: nguchhait@yahoo.com.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Guchhait
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D019800:Phenol / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory
chemical_list: D052160:Benzothiazoles; D011522:Protons; D019800:Phenol
keywords: Aromaticity; Atoms-In-Molecules; ESIPT; Hyperconjugative charge transfer; Intramolecular hydrogen bond; Natural Bond Orbital