Synthesis and second-order nonlinear optical properties of bis(salicylaldiminato)M(II) metalloorganic materials

A new synthetic strategy to second-order nonlinear optical (NLO) metalloorganic chromophores has been developed. These materials exhibit a sizable nonlinearity, an excellent thermal stability, and can be easily incorporated in thermally stable main-chain polymers for poled polymer NLO applications. In addition, substituted donor–acceptor derivatives exhibit two-dimensional NLO characteristics. The effect of the metal center in such complexes is manifold; it templates the formation of acentric molecular structures, imparts high thermal stability to the chelate ring, and both ‘switches on’ and enhance NLO response. This paper briefly reviews recent research developed in our laboratory on this new class of NLO materials.