New syntheses and spectral properties of diazepine fluorescent dyes with non-planar molecular structure

Two types of new diazepine fluorescent dyes were synthesized by the condens ation of N-(4-substituted-4-oxo-2-buten-2-yl)diaminomaleonitrile and 2,3-di cyano-6H-1,4-diazepines with an arylaldehyde. Regioselective condensation r eaction are observed and their reactivities are evaluated from their optimi zed molecular structures obtained by means of the ab initio molecular orbit al calculation methods. Substituent effects of the donor moiety to absorpti on and fluorescent properties in solution were correlated with chromophoric systems with regard to the non-planar diazepine moiety. A strong intramole cular charge-transfer chromophoric system of dyes are confirmed and its lar ge Stokes shift of over 100 nm. resulted in emission of red fluorescence. T hese dyes are of current interest as a red light emitter for electrolumines cence devices. (C) 2001 Published by Elsevier Science Ltd. All rights reser ved.