The structure of arylosazones

Article abstract of DOI:10.1016/0584-8539(81)80131-6

The u.v./visible spectra of arylosazones have been examined.These show that in nonchelated arylosazones the ?-electrons in both arylhydrazone groups are highly delocalised, compared to those of simple arylhydrazones, but that there is very little, if any, electronic interaction between the two 10?-electron systems.Both chromophores contribute separately to the absorption spectrum.In chelated arylosazones only one of the arylhydrazone groups has this enhanced electron delocalisation, and an explanation for this is proposed.The delocalisation causes an increase in the N-N bond order and a reduction in the C-N bond order.The delocalised structures proposed for both chelated and non-chelated arylosazones enable a number of the known properties of sugar phenylosazones to be now statisfactorily explained.