Multidecker Sandwich Cluster VnBenn+1 (n = 1, 2, 3, 4) as a Polarizable Bridge for Designing 1D Second-Order NLO Chromophore: Metal−π Sandwich Multilayer Structure as a Particular Charge-Transfer Axis for Constructing Multidimensional NLO Molecules

Abstract

Multidecker sandwich π-coordination complexes with multiple metal atoms and cyclic π-ligands can be considered as building blocks for designing NLO molecules. In a previous work, we found that multidecker sandwich complexes of the form VnBzn+1 (n = 1, 2, 3) can be considered as stronger electron donors than metallocene Fe(η5-C5H5)2 for the design of second-order NLO molecules, and a layer-number dependence of the first hyperpolarizability of VnBzn+1–(C2H2)3–NO2 (n = 1, 2, 3) and the two-dimensional NLO character was observed from our calculation results. In the present article, by analogy with traditional donor–acceptor substituted conjugated polyenes, we took the multidecker sandwich complexes VnBzn+1 (n = 1, 2, 3, 4) as the polarizable bridge instead of the traditional π-electron conjugated bridge and designed several novel push–pull systems of the form donor–(VnBzn+1)–acceptor (n = 1, 2, 3, 4) by introducing electron-donating and electron-withdrawing groups at the terminal benzene ring of VnBzn+1. The ...