Design, Assembly And Properties Of Transition Metal–organic Complexes Based On Polyoxometalates And Amino Triazole Ligands

In this paper, nine polyoxometalates(POMs)-directed(including Keggin-type and Anderson-type POMs, isopolymolybdates and isopolyvanadates) transition metal-organic complexes based on amino triazole ligands have been synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR, TG, PXRD and single crystal X-ray diffractions. The photocatalytic properties of all the compounds and magnetic properties of some compounds have been studied as well.1. Different types of POMs anions were used as inorganic building units, and 4-amino-1,2,4-triazole was used as organic ligand with the reaction of Cu(NO3)2·6H2O under hydrothermal conditions, resulting in five new POM-based compounds containing multinuclear copper clusters. Influence of the citric acid and boric acid on the formation of crystals and the influence of different POMs on the final crystal structures have been explored and discussed.[Cu3(4-atrz)8(PMo12O40)2(H2O)2]·2H2O(1)[Cu2(4-atrz)6(Si W12O40)(H2O)]·6H2O(2)[Cu2(4-atrz)4(μ2-OH)(Cr Mo6H6O24)]·3H2O(3)[Cu3(4-atrz)3(Mo8O27)(H2O)4]·6H2O(4)[Cu3(4-atrz)3(V10O30)0.5(μ3-OH)(H2O)]·H2O(5)4-atrz = 4-amino-1,2,4-triazoleCompound 1 is a zero-dimensional(0D) architecture, which is constructed from a linear trinuclear cluster [Cu3(4-atrz)8(H2O)2]6+ and two Keggin PMo12O403- anions. Compound 2 shows a 1D zigzag chain, in which the binuclear [Cu2(4-atrz)6(H2O)]4+ clusters and Keggin Si W12O404- anions connect each other. Compound 3 is a 1D linear chain based on the linear [Cu3(4-atrz)6]6+ clusters, the [Cr Mo6(OH)6O18]3- anions hang on two sides of the 1D chain. Compound 4 is a 2D layer constructed from trigonal [Cu3(4-atrz)3(H2O)4]6+ clusters and rare infinite [Mo8O27]n6n- chains. The [Mo8O27]6-anion is transformed from the Anderson-type [Co Mo6(OH)6O18]3- anion, which is also rare in the POM-based reaction system. Compound 5 is a 3D framework constructed from the trigonal trinuclear [Cu3(4-atrz)3(OH)]5+ clusters and rare [V10O30]10-polyanions, which represents the first example of V10O30-based 3D metal–organic complex.The photocatalytic experiments manifest that compounds 1–3 are good candidates for the photocatalytic degradation of methylene blue, and compound 1 is a good photocatalyst for the degradation of rhodamine B.2. 3-amino-1,2,4-triazole and 4-amino-1,2,4-triazole are selected as the ligands to react with different transition metal salts and sodium metavanadate under hydrothermal conditions, four new diverse metal-organic complexes based on polyoxovanadates were successfully synthesized. Effect of different ligands and metal ions on the dimension and structures of the compounds have been explored and discussed.[Ni(3-atrz)2V2O6]·2H2O(6)[Ni3(4-atrz)6V6O18]·4H2O(7)[Co3(4-atrz)6V6O18]·4H2O(8)[Zn3(4-atrz)6V6O18]·4H2O(9)3-atrz = 3-amino-1,2,4-triazoleCompound 6 shows a one-dimensional(1D) chain formed by the alternative arrange of linear trinuclear [Ni3(3-atrz)6]6+ clusters and hexanuclear [V6O18]6- clusters. Compounds 7–9 are isostructural three-dimensional(3D) frameworks, which are constructed from the linear trinuclear transition metal clusters and 2D inorganic layers derived from transition metal ions and hexanuclear [V6O18]6- clusters.The photocatalytic experiments manifest that compounds 8 and 9 have obviously photocatalytic degradation for methylene blue.