Construction and isomer recognition of polyoxometalates functionalized by 1,2-dimethylimidazole alkane templates

Eleven novel inorganic–organic hybrid polyoxometallates, namely, [1,2-bis(1,2-dimethylimidazole)methane]3[β-HMo8O26]2·[H3O+]2·7H2O (1), [1,2-bis(1,2-dimethylimidazole)ethane]2[β-Mo8O26]·H2O (2), [1,2-bis(1,2-dimethylimidazole)propane]2[α-Mo8O26] (3), [1,2-bis(1,2-dimethylimidazole)butane]2[γ-Mo8O26] (4), [1, 2-bis(1,2-dimethylimidazole) pentane]3[β-Mo8O26]2[H3O+]2 (5), [1,2-bis(1,2-dimethylimidazole) hexane]4[β-Mo8O26]2 (6), [1,2-bis(1,2-dimethylimidazole)heptane][Mo6O19] (7), [1,2-bis(1,2-dimethylimidazole) octane] [Mo6O19] (8), [1,3,5-tris[(1,2-dimethylimidazole-3-iumyl)benzene)]2[β-Mo8O26]1.5·2H2O (9), [1,3,5-tris[(1,2-dimethylimidazole-3-iumyl)-2,4,6-trimethyl benzene)]4 [α-Mo8O26]2 [Mo6O19]2·4H2O (10), [1,3,5-tris[imidazol-1-ylmethyl)-2,4,6-trimethyl benzene)]2 [β-Mo8O26] [Mo6O19] (11) were synthesized by the cation-templated self-assembly with octamolybdate or hexamolybdate anions under hydrothermal reaction conditions. Crystal data analysis revealed that these compounds were all composed of discrete organic cations and polyacid anions interacted by electrostatic and hydrogen bond interactions. Interestingly in these compounds the anion fraction could take on [β-Mo8O26]4− cluster, α-[Mo8O26]4− cluster, γ-[Mo8O26]4− cluster, [Mo6O19]2− cluster or two mixing kinds of polyoxomolybdate anions with the modification of lengths of alkane components or change the valence configuration of the templates.