Spectral Studies and Normal Coordinate Analysis of Some Symmetric 1,5-Diaryl-3-cyanoformazans

摘要

The 1,5-diaryl-3-cyanoformazans were prepared and and subjected to IR, MS, ~1H NMR, and ~(13)C NMR spectral analysis. The results indicate the presence of a strong intramolecular hydrogen bond in the formazan molecule. Moreover, the two phenyl rings are equivalent and the C ident to N and N-H stretching vibrational modes are slightly affected with electron-withdrawing substituents and interact with the neighboring C-C stretching mode. The syn, s-cis formazan form was supported by calculating the frequencies, normal coordinate analysis, force constant refinement, and group theory treatment. High quality of fitting between the experimental and calculated frequencies with all formazans has been achieved.