Ligands directed versatile cadmium-bis(triazole) metal–organic fragments to generate three new two dimensional complexes based on polymolybdenum phosphate

Three new two dimensional (2D) polymolybdenum phosphate-based cadmium complexes, [Cd2.5(btp)2(H2O)3][Cd0.5(PO4)(HPO4)3(MoO2)6(OH)3]·2H2O (1), [Cd(Hbtb)(H2O)]4[Cd(PO4)4(HPO4)4(MoO2)12(OH)6]·6H2O (2) and [Cd(H2O)2][Cd(H2O)(Hbth)]2[Cd0.5(H2O)(bth)]2[Cd(PO4)4(HPO4)2(H2PO4)2(MoO2)12(OH)6]·4H2O (3) (btp = 1,3-bis(1,2,4-triazol-1-yl)propane, btb = 1,4-bis(1,2,4-triazol-1-yl)butane and bth = 1,6-bis(1,2,4-triazol-1-yl)hexane), have been synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Single crystal X-ray diffraction analyses reveal that all the compounds are based on the polymolybdenum phosphate [P4Mo6O28(OH)3]9− ([P4Mo6]) units, which are further connected into sandwich-type [Cd(P4Mo6)2] dimers by cadmium ions, and different multi-nuclear CdII subunits. There exist penta-nuclear subunits in 1, which are further connected by btp ligands to form 1D chains; tetra-nuclear fragments in 2; and a 1D zigzag Cd–O–P chains based on tri-nuclear CdII units in 3, all of which are extended into different 2D networks by [Cd(P4Mo6)2] dimers. The –(CH2)n– spacers of the bis(triazole)-based ligands play an important role in the formation of multi-nuclear CdII subunits and the ultimate 3D supramolecular frameworks. Moreover, the thermal stabilities, electrochemical properties of the title compounds have been investigated in this paper.