Ion Pair Charge-Transfer Salts Based on Metal Chalcogenide Clusters and Methyl Viologen Cations

A study was conducted to prepare cluster-based charge transfer salts by integrating crystalline Cds semiconducting metal-chacogenide clusters with methyl viologen cation to form ion pair charge-transfer (IPCT) salts. All compounds were synthesized by solution processor under solvothermal conditions. The crystal structure analysis of IPCT demonstrated that these materials were made of tetrahedral clusters and charge balancing methyl Viologen cations. The deep-red color of crystals together with red-shifted UV-vis absorption spectrum showed a geometric features of an ion-pair charge-transfer complex. The composition of IPCT was MV₂[Zn₁₀S₄(SPh)₁₅Cl], which consist of supertetrahedral T3 clusters. It is concluded that the salts that exhibit red-shift UV-visible absorptions has provided a new way to control optical and electronic properties of metal chalcogenides.