Vibrational analysis of substituted phenols: part II. Transferability of valence force constants

A zero-order normal coordinate analysis was made for the in-plane and out-of-plane vibrations of 2,6-dimethylphenol, 2,3-dimethylphenol, 3,5-dimethylphenol, 2,6-dichloro-4-nitrophenol, 2,4-dichloro-6-nitrophenol, 3-chloro-4-hydroxy-5-methoxybenzaldehyde, 3-bromo-4-hydroxy-5-methoxybenzaldehyde and 3-iodo-4-hydroxy-5-methoxybenzaldehyde and for the in-plane vibrations of 2-amino-4-nitrophenol by transferring the force constants obtained beforehand. The transferability of the force constants was demonstrated by the good agreement between the observed and calculated frequencies. On the basis of calculated potential energy distributions and eigenvectors, several assignments suggested by earlier workers have been revised.