Influence of N-substituent and solvent on internal conversion in 1-aminonaphthalenes

N-Methyl-N-methoxycarbonylmethyl-1-aminonaphthalene (MMAN) and N,N-dimethoxycarbonylmethyl-1-aminonaphthalene (DCAN) were synthesized and their fluorescence and absorption spectra in solvents of varied polarity were investigated and compared to those of 1-dimethylaminonaphthylene (DMAN). The data were discussed in terms of the N-substitution effects on the internal conversion (IC). Results showed that the IC was enhanced when the N-methyl group in DMAN was replaced by N-CH2CO2CH3.