Synthesis, crystal structure and non-linear optical properties of the heterobimetallic polymeric compound {[n-Bu4N][W2Ag3S8]}n

Abstract

The heterobimetallic, polymeric compound has been synthesized by the reaction of (NH₄)₂WS₄ and AgBr with n-Bu₄NBr in CH₂Cl₂ solution under a purified nitrogen atmosphere using standard Schlenk techniques. The crystals were characterized by elemental analysis, IR and single-crystal X-ray crystallography. The polymeric anion has a hanging ladder-like polymeric chain which can also be described as double helical chains bridged by silver atoms. Its non-linear optical properties (NLO) were investigated using Z-scan techniques with an 8 ns pulsed laser at 532 nm, and the cluster also exhibits both strong non-linear optical absorption and an optical self-defocusing effect (effective α₂ = 1.11 × 10⁻¹⁰ m W⁻¹, n₂ = 3.67 × 10⁻¹⁸ m² W⁻¹, when measured with a 1.2 × 10⁻⁴ mol dm⁻³ DMF suspension).