Octamolybdate-Based Metal–Organic Framework with Unsaturated Coordinated Metal Center As Electrocatalyst for Generating Hydrogen from Water

Two octamolybdate-based MOFs with unsaturated coordinated metal centers formulated as Cu₃(Mo₈O₂₆)­(H₂O)₂(OH)₂(L1)₄ (L1 = 4H-4-amino-1,2,4-triazole) (1) and Ag₄(Mo₈O₂₆)­(L2)_2.5(H₂O) (L2 = 3,5-dimethyl-4-amino-4H-1,2,4-triazole) (2) were synthesized and structurally characterized by single-crystal X-ray diffractions. Complex 1 exhibits a 1D chain-like structure. In complex 2, 1D Ag-octamolybdate chains in the ac plane are covalently embedded into the 2D Ag-L2 layer, and the Ag-octamolybdate chains in the bc plane covalently link the 2D layers into 3D architecture. The two complexes both exhibit electrocatalytic activities toward generating H₂ from water with lowered overpotentials and enhanced currents, and the Cu complex exhibits better electrocatalytic activity toward generating H₂ from water than the Ag complex.