title: The key role of -CH3 steric hindrance in bis(pyrazolyl) ligand on polyoxometalate-based compounds.
abstract: Through using two kinds of bis(pyrazolyl) ligands, four polyoxometalate (POM)-based compounds were hydrothermally synthesized and structurally characterized, [Ag3(Hbhpe)2(H2O)(H2PMo12O40)]·H2O (1), [Ag(H2bdpm)2(H2PW12O40)]·4H2O (2), [Ag6(H2bdpm)6(HPW(VI)8W(V)4O40)]·2H2O (2) and [Ag4(H2bdpm)4(H2P2W18O62)]·3H2O (4) (H2bhpe = 1,2-bis(1-H-pyrazolate)ethane, H2bdpm = 1,1'-bis(3,5-dimethyl-1H-pyrazolate)methane). In compound 1, the Ag-Hbhpe subunit is a 2D layer containing large penta-membered cycles and small tri-nuclear Ag(I) clusters. The Keggin anions covalently float on the large cycles. In compound 2, the Keggin anions are fused by [Ag(H2bdpm)2](+) subunits to form a 1D chain. Compound contains hexa-membered metal-organic cycles, which are further linked by Keggin anions to build a 1D chain. Adjacent chains share the Ag(I) ions to construct a 3D framework of 3. Compound 4 exhibits a wavy double-track chain structure, with the Wells-Dawson anions covalently suspended up and down this chain. The steric hindrance of -CH3 groups in H2bdpm leads to the formation of mono-nuclear Ag(I) subunits in 2 - 4. The influence of -CH3 steric hindrance in bis(pyrazolyl) ligands on the structures of 1 - 4 is discussed. The electrochemical and photocatalytic properties of the title compounds have been studied.
authors.affiliation: Department of Chemistry, Bohai University, Jinzhou, 121000, P. R. China. tianax717@163.com wangxiuli@bhu.edu.cn.
authors.forename: Ai-xiang
authors.initials: AX
authors.lastname: Tian
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Ying
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Xiao-ling
authors.initials: XL
authors.lastname: Lin
authors.forename: Ju-wen
authors.initials: JW
authors.lastname: Zhang
authors.forename: Xiu-li
authors.initials: XL
authors.lastname: Wang
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D006861:Hydrogen Peroxide / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009573:Nitrites / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D011720:Pyrazoles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D006861:Hydrogen Peroxide; D008024:Ligands; D009573:Nitrites; D009942:Organometallic Compounds; D011720:Pyrazoles; D012834:Silver; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates