P. Gilli, V. Bertolasi, L. Pretto
Mar 11, 2005
Citations
0
Influential Citations
111
Citations
Quality indicators
Journal
Journal of the American Chemical Society
Abstract
Phenyl-substituted 1-arylazo-2-naphthols (AAN) display ···HNNCCO··· ⇌ ···NNCCOH··· ketohydrazone−azoenol tautomerism and can form intramolecular resonance-assisted H-bonds from pure NH···O to pure N···HO through tautomeric and dynamically disordered NH···O ⇌ N···HO bonds according to the electronic properties of their substituents. Three compounds of this series (m-OCH3-AAN = mOM; p-Cl-AAN = pCl; and p-NMe2-AAN = pNM2) have been studied by X-ray crystallography at four temperatures (100−295 K), showing that the remarkably short H-bonds formed (2.53 ≤ d(N···O) ≤ 2.55 A) are a pure NH···O in mOM, a dynamically disordered mixture in pCl (NH···O:N···H−O = 69:31 at 100 K), and a statically disordered mixture in pNM2 (NH···O:N···HO = 21:79 at 100 K). These compounds, integrated by the p-H-, p-NO2-, p-F-, and p-O--substituted derivatives, have been emulated by DFT methods (B3LYP/6-31+G(d,p) level) with full geometry optimization of the stationary points along the proton-transfer (PT) pathway: NH···O and N···HO ...