DFT and FT-IR analyses of hydrogen bonding in 3-substistuted-3-oxo-arylhydrazonopropanenitriles.
Ab initio calculations, FT-IR and X-ray crystal analysis, indicated that the most stable configuration of 3-oxo-2-(phenylhydrazono)-3-(thien-2-yl)-propionitrile is the anti phenylhydrazone structure 1. Stability of such a conformation, over the possible E-form, 2, that would be stabilized by intramolecular hydrogen bonding, is due to interaction between electron-pair domains of the N, S and O atoms. However, the simulated and experimental IR frequency data indicated intermolecular hydrogen bonding between NH and CN, the latter being lowered to 2214 cm(-1). Studies on 3-oxo-3-phenyl-2-(phenylhydrazono)-propionitrile showed the same result, as well as, another intramolecular hydrogen association of the type N-H...O. This was clearly indicated by the absorbance of the carbonyl stretch at 1605 cm(-1). These data indicated the existence of a bifurcated hydrogen bond in 1a and a single intermolecular association in 1b.
Kenawi
Ihsan M
IM
Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt. ihsanata77@hotmail.com <ihsanata77@hotmail.com>
Elnagdi
Mohamed H
MH
D018360:Crystallography, X-Ray; D006835:Hydrazones / Q000737:chemistry*; D006860:Hydrogen Bonding; D008432:Mathematical Computing; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
C517347:3-oxo-3-phenyl-2-(phenylhydrazono)-propionitrile; D006835:Hydrazones; D009570:Nitriles; C005557:propionitrile