Effect of the amino group on the properties of 1-(benzylideneamino)pyridinium salts

Eleven (E)-4-t-butyl-1-(4-dimethylaminobenzylideneamino)pyridinium perchlorates were obtained by the condensation of 1-amino-4-t-butylpyridinium perchlorate with p-amino-benzaldehydes. The position of the primary band in their UV/VIS spectra was not simply related to the sigma substituent constants of the different amino groups. Only two compounds were found to be fluorescent and piezochromic. (C) 2003 Elsevier Ltd. All rights reserved.