Hydrogen Complexes of O-Vinylacetoxime with Trifluoroacetic Acid

摘要

According to B3LYP/6-31G** calculations,the stable antiperi-,antiperiperiplanar and antiperi-,synperiperiplanar conformers of O-vinylacetoxime(1)form with trifluoroacetic acid strong H complexes of two types:with N…H-O and O…H-O hydrogen bonds.The former are more stable.Complexation changes N-O and C-O bond lengths in molecule 1,as well as mutual orientation of its vinyl and azomethine groups.The structural effect depends on the orientation of the H bond,which,in its turn,is determined by the nature of the electron-donor center.When the nitrogen atom of oxime 1 is involved in complex formation,the H bond lies in the molecular plane,whereas the H bond involving the oxygen atom is directed in parallel with its lone electron pair.