INVESTIGATION OF HYBRIDIZATION OF OXYGEN ATOM IN n, v-TYPE COMPLEXES BY METHODS OF X-RAY ANALYSIS, NUCLEAR MAGNETIC RESONANCE, AND ELECTRONIC SPECTROSCOPY
The <sup>1</sup>H NMR and X-ray analysis proved that the space structure and hybridization type (sp <sup>2</sup> or sp <sup>3</sup>) of the oxygen atom of N-oxide group in n,v-type molecular complexes of heteroaromatic N-oxides with BF <sub>3</sub> and other Lewis acids depend on electronic factors of the substituents in pyridine ring, solvent type, and space bulks during complexation. For example, in CDCl <sub>3</sub> and DMSO-d <sub>6</sub> in ad-duct of 4-methylpyridine N-oxide with boron trifluoride bond O-B lies in plane of pyridine cycle (sp <sup>2</sup>-hybridization), but in crystal dihedral the angle between planes of N-O-B atoms and pyridine ring is 87,81o (sp <sup>3</sup>-hybridization). Perhaps hybride state of the oxygen atom in n,v-type complexes of carbonylic compounds (aldehyds, ketones, carboxylic acids and their functional derivatives) depends on the same factors.