Two rare {M(MoO)} chain-containing molybdate-based metal-organic complexes with a bis-pyrazole-bis-amide ligand: fluorescent sensing and photocatalysis performance.

By introducing a bis-pyrazole-bis-amide ligand, ,'-bis(1-pyrazole-4-carboxamide)-1,4-benzene (L), two molybdate-based metal-organic complexes containing {M(MoO)} (M = Co, Zn), [CoL(MoO)]·HO (1), [ZnL(MoO)]·HO (2), have been prepared under hydrothermal/solvothermal conditions. X-ray diffraction analyses reveal that both 1 and 2 are isostructural. An interesting structural feature is that a kind of {M(MoO)} chain could be found in 1 and 2, although different raw materials [MoO] and [PMoO] anions were utilized. Then these chains are further linked by L ligands into a two dimensional (2D) structure. The title complexes represent the first examples containing {MoO} units and pyrazole-/or amide-derivative ligands. Complexes 1 and 2 exhibit distinct performances due to different metal centers, with 2 acting as a fluorescent sensor for Fe, MnO , CrO and CrO , but 1 being a better photocatalyst towards degradation of cationic dyes methylene blue (MB) and neutral red (NR).