Synthesis, Characterization And Properties Of Series Of Sadnwich Type Polyoxometalates

Recently,the design and synthesis of organic-inorganic hybrid compounds based on polyoxometalate blocks and transitional metal molybdenum phosphates are of great interest owing to not only their intriguing structural frameworks but also potential applications in catalysis,electronic conductivity and material etc.In this paper,seven sandwich type transitional metal or alkaline metal molybdenum phosphate complexs are synthesized on the basis of hydrothermal technique and structurely characterized by elemental analyses, IR,UV-vis and single crystal X-ray diffractions.The innovative achievements of the paper include:1.Coexisting isolated V-shaped neutral water trimers and proponated diethylenetriamine(deta) molecules form an unprecedented interesting hydrogen bonded 1D belt arrangement via intricate hydrogen bonding interactions in the host crystal lattice of a new ferrous molybdenum(V) phosphate,[C₄H₁₅N₃]₄(H₃O)⁺ {Na[Fe^â…¡Mo₁₂^â…¤O₂₄(OH)₆(HPO₄)₆(PO₄)₂]}·6H₂O (C₄H₁₃N₃=diethylenetriamine),which is prepared under hydrothermal condition and characterized by elemental analyses,IR,UV-vis,TG-DTA, cyclic voltammetry and single-crystal X-ray diffraction.The hydrogen-bonded 1D arrangement plays an important role in stabilizing and influencing through intermolecular non-covalent interactions the arrangement of the surroundings herein refering to a new 1-D inorganic anion chain constructed by the versatile building blocks of the formula Fe[Mo₆P₄O₃₁]₂ covalently connected with NaO₆ octahedra.2.An unprecedented H-bonded 2-D arrangement consisting of water dimers, V-shaped water trimers and protonated diethylenetriamine(deta) molecules is crystallographically characterized for the first time in the host crystal lattice of a new reduced molybdenum(V) phosphates [H₂deta]₄ {Na[NaMo₁₂^â…¤O₂₄(OH)₆(H₂PO₄)₂(HPO₄)₄(PO₄)₂]}·8H₂O(C₄H₁₃N₃ =diethylenetriamine) which is prepared under hydrothermal condition and characterized by elemental analyses,IR,UV-vis,TG-DTA,cyclic voltammetry and single-crystal X-ray diffraction.The harmonious assembly of the small dimer and trimer water clusters and deta molecules is significant in stabilizing and influencing the arrangement of their surroundings which herein refers to the 1-D inorganic anion chains constructed by the versatile building blocks of the formula[Mo₆P₄O₃₁] covalently connected with NaO₆ octahedra,giving rise to a 3-D arrays via complex hydrogen bonding interactions.3.One composite solids consisting of one-dimensional mixed-valence iron and molybdenum phosphates with metal complexes, [(C₁₃H₁₄N₂)₃H₆]Fe₂^â…¡Fe₂^â…¢Mo₂₄^â…¤(H₂PO₄)₈(HPO₄)₄(PO₄)₄O₄₈(OH)₁₂(H₂O)₄·4H₂O (C₁₃H₁₄N₂=1,3-di(4-pyridyl)propane=bpp) 1,in which the one-dimensional inorganic anion chains are constructed of alternating[Fe^â…¡(P₈Mo₁₂)]and Fe^â…¢ions,which is same as the compounds [(C₁₀H₁₈N₂)₃Fe^â…¡]₃Fe₂^â…¢Fe₂^â…¡Mo₂₄^â…¤(H₂PO₄)₈(HPO₄)₄(PO₄)₄O₄₈(OH)₁₂(H₂O)₄·2H₂O2 and[(C₁₀H₈N₂)₃Fe^â…¡]₂Feâ…¡Feâ…¢MoV₁₂(H₂PO₄)₂(H_2-xPO₄)(H_1-xPO₄) (HPO₄)₂(PO₄)₂O₂₄(OH)₆(H₂O₎₂·9H₂O(x=0-1)(C₁₀H₁₈N₂=2,2'-bipyridine) 3, which we have reported earlier,and characterized by elemental analysis and single-crystal X-ray diffraction.Because organic ligands as structure directing agents have significant influence on the arrangement pattern of one-dimensional mixed-valence iron molybdophosphate anion chains,the one-dimensional inorganic anion chains are further connected together by bbp (bpp=1,3-di(4-pyridyl)propane) to produce an interesting interpenetrating 3D network structure in 1.Otherwise,Fe(2,2'-bpy)3 complexes which are situated between the layers which were formed via the hydrogen bond interactions in 2 and 3.4.Two ferrous molybdenum(V) phosphates,(C₃H₁₂N₂)₇Fe^â…¡[Mo₁₂^â…¤(HPO₄)₂ (PO₄)₆(OH)₆O₂₄]·8H₂O and(C₃H₁₂N₂)₆Fe^â…¡[Mo₁₂^â…¤(HPO₄)₄(PO₄)₄(OH)₆O₂₄]·4H₂O(C₃H₁₂N₂=1,2-propanediamine) obtained from an identical starting mixture through hydrothermal reactions using temperature as the only independent variable which allowed two different energetic processes to be clearly evidenced.It is shown that increasing reaction temperature leads to less protonation of the PO₄ groups with the result that the anion carry much charges and subsequently give rise to much numbers of protonated 1,2-propanediamine cation per Fe^â…¡(Mo₆^â…¤P₄)₂ unit,though the non-hydrogen atomic ratios among Mo,Fe,P,O in the anions are the same.All of these 1,2-propanediamine molecules have important role in forminig interpenetrating 3D H-bond network structure.5.A new reduced ferrous molybdenum(V) phosphates (C₆H₂₂N₄)₃ {Fe^â…¡Mo₁₂^â…¤(OH)₆(HPO₄)₄(PO₄)₄O₂₄}·6H₂O(C₆H₁₈N₄= triethylenetetramine) which is prepared under hydrothermal condition and characterized by elemental analyses,IR and single-crystal X-ray diffraction.Coexistence of water dimer and chain-like water tetramer in Fe^â…¡[Mo₆P₄O₃₁]₂ inorganic building blocks host.Water dimers and "Z" type water tetramers connect Fe^â…¡[Mo₆P₄O₃₁]₂ inorganic building blocks through complex hydrogen bond,giving rise into 3D H-bond network supermolecule structure.6.A new reduced molybdenum(V) phosphates(C₆H₂₂N₄)₄NaMo₁₂^â…¤(OH)₆ (HPO₄)(PO₄)₇O₂₄·10H₂0(C₆H₁₈N₄=triethylenetetramine=teta) which is prepared under hydrothermal condition and characterized by elemental analyses,IR and single-crystal X-ray diffraction.The structure of Na[Mo₆P₄]₂ dimer have two type:standing and lying.Sandwich type molybdenum phosphate Na[Mo₆P₄]₂ dimers act as the templated, two-dimensional hydrogen-bond network[(H₂O)₄(teta)]_n based on acyclic water tetramer clusters and triethylenetetramine molecules have been formed. There are many hexagonal pores in the two-dimensional hydrogen-bond network,which is contructed by acyclic water tetramer clusters and triethylenetetramine molecules through hydrogen bonds.The standing and lyinig Na[Mo₆P₄]₂ dimers that is alternately arranged on the hexagonal voids results in a 3D structure through hydrogen bonds between Na[Mo₆P₄]₂ dimers and[(H₂O)₄(teta)]_n two-dimensional network.