Synthesis of chromophores based on the hydrazinylidene cyclic acceptor moieties via the reaction of organolithium reagents with diazo compounds

Abstract

An approach to the synthesis of D-A chromophores containing hydrazinylidene cyclic acceptor moieties via the reaction of organolithium reagents with cyclic diazo compound precursors was developed. In contrast to conventional approaches the new one allows to introduce thiophene fragments into a chromophore molecule which is important for the better molecular planarity. The approach demonstrated convenience for the synthesis of hydrazinylidenecyclopentadiene, hydrazinylidenebarbituric and hydrazinylideneindanedione chromophores and a series of hydrazonocyclopentadienes with various aromatic and heterocyclic substituents were synthesized. The products demonstrated intense absorption of visible light with absorption maxima within 373–562 nm and extinction coefficients up to 36500 М−1⋅cm−1. Importantly, previously unavailable thiophenylhydrazones displayed longer wavelength absorption maxima and higher extinction coefficients relative to conventional arylhydrazones.