The force field of 4-vinylpyridine and 4-vinylpyridine metal complexes

A normal coordinate analysis is carried out to obtain the Urey–Bradley force constants for 4-vinylpyridine (4-vipy) assuming under C2v point group. These constants are adjusted to fit the observed frequencies for 4-vipy and its deuterated species. The calculated frequencies are found to reproduce well experimental infrared spectrum of liquid 4-vipy. Two new Hofmann-Td-type complexes of the form Cd (4-vipy)2 M (CN)4 (M=Cd, Hg) have been prepared and their infrared spectra are reported. The coordination effect on the ligand vibrational modes was also investigated. It is shown that the ring vibrations in pyridine are to be effected upon metal substitution.