Conformational analysis of cationic complexes of heteroaromatic N-oxide

N-O group can have electron-donor or electron-acceptor properties depending on the structure of heteroaromatic N-oxides. It was suggested that the oxygen atom in complexes of this compounds can have sp3-hybridization or sp2-hybridization. To check this hypothesis, we carried out conformational analysis of four solts of heteroaromatic N-oxides: bis(pyridine-N-oxide)hydrogen bis(2-methyl-pyridine-N-oxide)hydrogen, bis(2,6-dimethylpyridine-N-oxide)hydrogen and bis(4-chloroquinolin-N-oxide)hydrogen. Since the energies corresponding to sp2-hybrid oxygen atom correspond to the maxima on the energy surface, the existence of steady adducts of N-oxides with sp2-hybridized oxygen atom in the solid phase can be questioned.