Selective and benign alkylation of sulfido-oxo stannate clusters with propyl, pentyl, or hexyl substituents

Chalcogenido metalate compounds that are based on tetrahedral clusters have been extensively studied in recent years due to their rich structural chemistry and uncommon chemical and physical properties. Recently it was shown that partial butylation of the inorganic cluster core by ionothermal reactions allowed access to tetrahedral sulfido-oxo stannate clusters with reasonable solubility in conventional solvents at the retainment of their opto-electronic features. We have expanded this mild alkylation approach, and herein report success in receiving the first sulfido-oxo stannate clusters that are selectively propylated, pentylated, and hexylated. This was achieved in a unique way by preparing symmetrically 1,3-substituted imidazolium bromides in preparative scale and using them as both the reaction medium and alkylatoin reagent. We discuss the effect of the organic groups attached to the cluster and present in the counterions of the products on the compounds' structural and opto-electronic properties. Salts of well-soluble clusters [Sn10O4S16(SR)4]4- (R = propyl, pentyl, hexyl) result from treatment of Na4[SnS4]center dot 14H2O with symmetrically bis-alkyl-functionalized imidazolium-based ionic liquids.

Automated summary

Chalcogenido metalate compounds based on tetrahedral clusters have been extensively studied. It has been shown that partial butylation of the inorganic cluster core allows access to tetrahedral sulfido-oxo stannate clusters with reasonable solubility in conventional solvents. In this study, selective propylation, pentylation, and hexylation of sulfido-oxo stannate clusters were achieved using symmetrically bis-alkyl-functionalized imidazolium-based ionic liquids. The effect of attached organic groups and counterions on the structural and opto-electronic properties of the compounds was discussed.