Two isostructural 3D metal–organic frameworks constructed from 1D [H2Mo4O14]n2n − chains and the flexible bis-pyridyl-bis-amide ligand

•Flexible bis-pyridyl-bis-amide L was introduced into the polyoxomolybdate system.•CoII (or NiII) ions connect 1D [H2Mo4O14]n2n − chains to form 2D bimetallic layers.•L link the adjacent 2D layers to construct a 3D framework with CdSO4 topology.•Both complexes show excellent electrocatalytic and photocatalytic activities.

Two new isostructural metal–organic frameworks based on 1D [H2Mo4O14]n2n − chains and the flexible N,N′-bis(3-pyridinecarboxamide)-1,2-ethane (L), [M(L)(H2Mo4O14)(H2O)2] (M = CoII for 1, NiII for 2), have been hydrothermally synthesized and characterized by single crystal X-ray diffraction. In the title complexes, the unusual 1D [H2Mo4O14]n2n − chains are linked by the MII ions to form a 2D inorganic bimetallic layer. The adjacent 2D layers are further connected by the L ligands to construct a 3D framework with CdSO4 topology. The electrochemical behaviors and the photocatalytic activities of the title complexes have been investigated.

Graphical abstractBy introducing the flexible N,N′-bis(3-pyridinecarboxamide)-1,2-ethane (L) in the polyoxometalate (POM) system, two new 3D POM-based metal–organic frameworks with CdSO4 topology were obtained, which represents the first example of POM-based complexes containing the unusual 1D polyoxomolybdate [H2Mo4O14]n2n − anion chains and flexible bis-pyridyl-bis-amide ligands. The title complexes show good electrochemical properties and dominant photocatalytic activities.Figure optionsDownload full-size imageDownload as PowerPoint slide