General trends in the molecular physics of azabiphenyls

Abstract

Some phenylpyridines and bipyridines have been studied by UV photoelectron spectroscopy and quantum-chemical methods. This study, together with some new computations on the previously reported bipyrimidines, has allowed a comprehensive analysis of general trends along the whole series of biphenyl-like molecules. Several physico-chemical characteristics have been considered in this respect, including geometric structure, conformational behaviour, relative stabilities, dipole moments and ordering of ionic states.

The results obtained have been analysed in terms of conjugative and steric interactions by means of fragment analysis. On these grounds simple thumb-rules have been suggested, which may prove useful for a better understanding of polyphenyl-like molecules.