Spectrochemical, ab initio and density functional studies on the conversion of 2-hydroxybenzonitrile (o-cyanophenol) into the oxyanion.
The spectral and structural changes caused by the conversion of 2-hydroxybenzonitrile (o-cyanophenol) into the corresponding oxyanion have been followed by IR spectra, ab initio and density functional force field calculations. In agreement between theory and experiment, the conversion is accompanied by a 29 cm(-1) frequency decrease of the cyano stretching band, 2.7-fold increase in its integrated intensity, 5.8-fold (total value) intensification of the aromatic skeletal bands of Wilson's 8 and 19 types, and other essential spectral changes. According to the calculations, the strongest structural changes are the shortening of the Ph-O bond with 0.10 A, lengthenings of the adjacent CC bonds in the phenylene ring with 0.06 A and bond angle variations near the oxyanionic center. All these changes are connected with the formation of a quasi-ortho-quinonoidal structure of the o-phenylene ring in the oxyanion. According to the electronic density analysis, 0.41 e(-) (Mulliken) or 0.56 e(-) (natural bond orbital, NBO) of the anionic charge remain localized at the oxyanionic center. Conformations and hydrogen bonds have also been discussed on the basis of experimental and theoretical data.
Institute of Organic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria. yb@orgchm.bas.bg
Yuri I
YI
Binev
Miglena K
MK
Georgieva
Lalka I
LI
Daskalova
D000838:Anions / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
D000838:Anions; D009570:Nitriles; D010636:Phenols; C014356:benzonitrile