Substituent effects on the spectra of fluorescent arylsubstituted N-methylpyrrolo[3,4-c]pyridines

Abstract Introduction of an alkoxy group into the phenyl ring at the 4 and 7 positions of the tetra-aryl derivatives 1, 6 and 7 has little effect on the absorption and emission spectra of a series of N-methylpyrrolo-[3,4-c]pyridines whilst introduction of a bromo substituent caused a red shift in the spectrum of 1. The nitrite derivative 1 the ester 8 and the 6-unsubstituted derivative 10 were strongly fluorescent whilst the fluorescence of 6 was weak; the hydrazide 9 and carboxylic acid 7 were also weakly fluorescent with a large Stokes shift (c. 150 nm). The pyridazines 13 and 14 were non-fluorescent.