| In this paper,by using metal ions AgI,CuII,CoII,NiIIand a series of rigid organic ligand,four metal-organic coordination polymers and eleven new POM-based compounds have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction,IR spectra and elemental analyses.The electrochemical and photocatalytic properties of some title compounds were investigated.1.Based on rigid ligand 2-?4-thiazolyl?-1H-benzimidazole?L1?and Cu II ions we have synthesized two Keggin-based compounds under hydrothermal conditions.[Cu II?L1?2?H2O?]2[SiW12O40]?1?[?L1?4?L2?2(H3PMo12O40)2]·5H2O?2??L1 = 2-?4-thiazolyl?-1H-benzimidazole,L2 =benzimidazole?.Compound 1 contains two discrete subunits,Keggin-type POM and a butterfly-style cationic complex [Cu?L1?2?H2O?]2+.Compound 2 owns mixed ligands,consisting of Keggin-type anion,four dissociative L1 and two L2 ligands.Furthermore,we studied the electrochemical and photocatalytic properties of compounds 1 and 2.2.Through using mixed N/S-containing ligand 2-?4-thiazolyl?-1H-benzimidazole?L1?and a second organic ligand benzenetricarboxylic?H3BTC?,four new metal-organic coordination polymers have been synthesized under hydrothermal conditions.[Co2?L1?4?HBTC??H2O?2]?3?,[Cu2?L1?2?HBTC?2]×H2O?4?,[Ni?L1?3]·?HBTC?×H2O?5?,[Ni?L1?3]·H2O?6?,?L1=2-?4-thiazolyl?-1H-benzimidazole,H3 BTC = benzenetricarboxylic?Compound 3 contains two {Co L2?H2O?} fragments,which are connected by a BTC molecule to form a discrete “V”-type subunit.The hydrogen bonding interactions between N3···O1 atoms induce a 1D chain of 3.Complex 4 includes bi-nuclear Cu II subunits,which are linked by BTC ligands to form a 2D layer.Each bi-nuclear Cu subunit is linked by four BTC molecules.Both complexes 5 and 6 are based on [Ni L3] subunits.In complex 5,when Ni Cl2·6H2O was used as reactant,a discrete BTC molecule is captured as a counter anion.In contrast,when using reactant Ni SO4·6H2O instead of [Ni L3]·H2O,complex 6 with different structure is formed.Both complexes 5 and 6 contain abundant hydrogen bonding interactions.In these four complexes,the N donors in L1 ligand coordinate with transition metals and the S atoms participate in hydrogen bonding interactions.3.Under hydrothermal conditions,by using Ag as metal centers,classical anions[PMo12O40]3-,[PW12O40]3-and [Si Mo12O40]4-as inorganic building blocks and choosing5-phenyl-1H-tetrazole?L3?and its derivative 5-m-tolyl-1H-tetrazole?L4?as organic ligands,three Keggin-based compounds have been constructed.[Ag9?L3?5(PWVWVI11O40)]·H2O?7?,[Ag11?L3?6?H2O?2(Si Mo VMo VI11O40)]?8?,[Ag10?L4?8(HPMo12O40)]·H2O?9?,?L3 = 5-phenyl-1H-tetrazole,L4 = 5-m-tolyl-1H-tetrazole?Compound 7 shows a channel-like 3D metal-organic framework with Keggin anions inserting into channels.Adjacent layers of compound 8 share the same anions to construct a 3D framework.Compound 9 owns a 2D metal-organic layer containing AgIcycles.Adjacent layers link each other through sharing Ag-N bonds and a channel-like 3D framework is formed.Furthermore,we studied the electrochemical and photocatalytic properties of the title compounds.The experimental results show that compounds 1-3 show excellent catalytic performance for the reduction of nitrite and bromate.Meanwhile,the title compounds also exhibit outstanding photocatalysts properties for the degradation of MB and Rh B.4.By using different organic ligands and octamolybdate,six POM-based compounds with different dimensionalities have been obtained.[Ag4?dpz?8(b-Mo8O26)]?10?,[Cu4?dpz?8(b-Mo8O26)]?11?,[Co2?L1?4?H2O?2(b-Mo8O26)]?12?,[Ni2?L1?4?H2O?2(b-Mo8O26)]·2H2O?13?,[Cu?L1?H2O(b-Mo8O26)1/2]?14?,[Cu?btp?2?H2O?(b-Mo8O26)1/2]·2H2O?15??dpz = 3,5-dimethyl-pyrazolidine,L1 =2-?4-thiazolyl?-1H-benzimidazole,btp = 1,3-bis?1,2,4-triazol-1-yl?propane?By using a dpz ligand,two isostructural 0D compounds 10 and 11 were obtained,with four{M?dpz?2} fragments?M = Ag for 10,Cu for 11?supporting one anion.When rigid L1 was used,0D compounds 12 and 13,and 1D structure of compound 14 was constructed.The L1 play a terminate chelate role in these compounds.By selecting a flexible bis?triazole?btp ligand with more N donors in 15,a 2D hamburger-like layer is formed.Adjacent layers further interpenetrate with each other to construct a 3D interpenetrating framework of compound 15,realizing dimensionality from 2D to 3D.Using different ligands to tune the dimensionality of POM-based structures is rational.Furthermore,the electrochemical and photocatalytic properties of some title compounds were investigated.The results show that the title compounds own good electrochemical and photocatalytic properties. |
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