Self-assembling of aminopyrazine fluorescent dyes and their solid state spectra

2,5-Diamino-3,6-dicyanopyrazine has strong yellowish-green fluorescence in spite of its small chromophoric system. Substitution at the amino groups, and hydrolysis followed by esterification of the cyano groups gave many types of fluorescent dyes. Their absorption and fluorescent spectra both in solution and solid state were correlated with their molecular stacking on vapor deposited thin film. Steric hindrances of the substitutents largely affected their solid state absorption and fluorescent spectra. Structural optimization by means of MOPAC PM3 method was conducted and these results well indicated their molecular stacking behaviors. (C) 1998 Elsevier Science Ltd. All rights reserved.