Large nonlinear optical absorption and self-defocusing effects of cluster [MoS₄Cu₄I₂(py)₆]

Abstract

Pentanuclear 'open' structure cluster com pound [MoS₄Cu₄I₂(py)₆] has been prepared by the reaction of (NH₄)₂MoS₄, CuI and 2,2' -bpy with py. Its nonlinear optical (NLO) properties

have been determined though Z-scan technique. The normalized transmittance of [MoS₄Cu₄I₂(py)₆] from NLO absorptive data drops to about 40% at the focus; it shows that the cluster has very strong NLO absorption. Its α₂ value was calculated to be 1.2×10^-9 m W^-1 in a 5.0×10^-5 mol dm^-3 DMSO solution. The value is the biggest for Mo-S clusters. The title compound has also strong self-defocusing behaviour. Its third-order NLO refractive index n₂ is -7.5×10^-7 m² W^-1. The data are superior to those of many Mo-S clusters.