The stereochemistry of molecules containing the CCN group. Part IV. X-Ray determination of the molecular structure of N-p-tolyl-2,2-diphenylvinylideneamine and N-p-bromophenyl-2,2-diphenylvinylidenamine

Abstract

The molecular structures of the isomorphous compounds N-p-tolyl-2,2-diphenylvinylideneamine (C₂₁H₁₇N, a= 11·446, b= 7·874, c= 18·355 Å, β= 101° 28′) and N-p-bromophenyl-2,2-diphenylvinylideneamine (C₂₀H₁₄BrN, a= 11·417, b= 7·869, c= 18·798 Å, β= 100° 46′) have been determined by X-ray diffraction analysis in space group P2₁/n with Z= 4. In all 2907 independent photographic intensities from the p-tolyl and 2239 from the p-bromophenyl compound were refined to R 8·06% and 9·33% respectively. The angle at the nitrogen atom is slightly greater than 120°, but the carbon–nitrogen distance in the chain appears to be abnormally short. The results are compared with those obtained previously for other molecules containing the CCN linkage.