| Arsenomolybdate polyacid is an important branch of POMs and is the focus of POMs chemistry. However, the preparation of such compounds is in need of toxic arsenic source such as As2O3 or organic arsenic, thus there is rare reported on them. This paper resorts to Na As O2 and Na3 As O4 with relatively low toxicity as arsenic source to synthesize 12 kinds of new arsenomolybdate POMs with different arsenomolybdate building blocks by means of hydrothermal synthesis method, changing the ratio of raw materials and adjusting the p H of the reaction system and controlling the reaction temperature. At the same time, the crystal structures are represented through elemental analysis, IR, TG, UV, XPS and X-ray diffraction thereby identifying the formula of the compounds as follows respectively:(H2bib)[{Cu(H2O)2(bib)}{H2As2Mo6O26}]·2H2O(1) [{CuI(dim)2}2{As2Mo6O26}{CuII2(dim)(H2O)2}](2) [{Cu(4,4’-bpy)1.5(H2O)2}2{H2As2Mo6O26}](3) [{Cu(bilb)1.5(H2O)}2{H2As2Mo6O26}]·2H2O(4) [{(Hbiyb)Cu(biyb)0.5}2{As2Mo6O26}]·2H2O(5) [{Cu2(bth)4}{H2As2Mo6O26}](6) [{Co(btb)(H2O)2}2{H2As2Mo6O26}]·2H2O(7) [H3pt]2[As2Mo6O26](8) [{Cu4(btp)4}{(Cu O6)(As3O3)2Mo6O18}]·2H2O(9) [{Cu(2,2’-bpy)}2{H2As2Mo2O14}](10) [H3biyb]2[B-As2Mo6O26(H2O)]·H2O(11) [Hbilb]2[HAs Mo12O40](12) [bib=1,4-Bis(1-imidazoly)benzene; dim= Diimidazole; 4,4’-bpy=4,4’-Bipyridine; 2,2’-bpy=2,2’-Bipyridine; bilb=1,4-Bis(benzoimidazo-1-yl)benzene; biyb=1,4-Bis(imidazol-1-ylmethyl)benzene; bth=1,6-Bis(triazol)hexane; btb=1,4-Bis(1H-1,2,4-triazol-1-yl)butane; pt=4’-(3’’-pyridyl)-2,3’:6’3’’-terpyridine; btp=1,3-Bis(1,2,4-triazol-1-yl)propane]Structural analysis shows that Compound 1-8 contain arsenomolybdate anion [Hx As2Mo6O26](6-x)-: In Compound 1, the organic ligand bib, water molecule and transition metal ion Cu2+ coordinate to form [Cu(H2O)2(bib)]2+ chain complex ion. [H2As2Mo6O26]4- acts as bisupported structures and complex ions to form a two-dimensional layer and the hydrogen bonding between layers and free and organic ligand bib constitutes a three-dimensional supramolecular structure. In Compound 2, there are two coordination ways between dim and the transition metal Cu ions: [CuI(dim)2]+ is located in the two ends of polyanions, [CuII2(dim)(H2O)2]4+ bridges two adjacent polyanions, thus forming the one-dimensional structure. At the same time, π-π stacking interactions exist between the organic ligand dim in [CuI(dim)2]+ and [CuII2(dim)(H2O)2]4+ and thus constitutes a two-dimensional structure. In Compound 3, polyanion [H2As2Mo6O26]4- takes bisupported structures to connect with the complex ion [Cu(4,4’-bpy)1.5(H2O)2]2+ to constitute a one-dimensional structure of this compound. The hydrogen bonding and supramolecular further constitutes the two-dimensional and three-dimensional structure. In Compound 4, ligand bilb exist in two forms, passing as monodentate and bidentate ligands bilb connects to Cu2+ which again connects to tetrahedral oxygen atoms in Mo O6 and As O4, thus in turn constituting a two-dimensional structure. In Compound 5, [As2Mo6O26]6- acts as a bidentate ligand, linking [(Hbiyb)Cu(biyb)0.5]3+ chains formed by Cu2+ and ligands biyb thus forming a two-dimensional structure of this compound. In Compound 6, Cu and ligand bth consist of an organic metal frame so that tetradentate ligand of polyanion [H2As2Mo6O26]4-connects to the metal frame; In Compound 7, [H2As2Mo6O26]4- connects to complex ion chains formed by Co2+, H2 O and btb by means of bidentate ligands so as to form a two-dimensional structure; Compound 8 is an organic-inorganic supramolecular compound containing [As2Mo6O26]6-.Compound 9-12 stand for compounds with four different arsenomolybdate anions: in Compound 9, polyacid anion [(Cu O6)(As3O3)2Mo6O18]4- is embedded in quad-core rings of [Cu4(btp)4]4+ complex ion in the form of “bullseye” which and the rings connect to each other and thus constitutes a one-dimensional structure of Compound 9. In Compound 10, chain polyacid anion [H2As2Mo2O14]n4n- is another new member of POMs; Compound 11 and 12 as organic-inorganic supramolecular compounds respectively contain [B-As2Mo6O26(H2O)]6- anions and Keggin-type [HAs Mo12O40]2-anions.The electrochemical experiments on Compound 1-12, which shows that 12 kinds of the compounds are all good at cyclic voltammetry stability. Meanwhile, the test of electrical catalytic properties on these 12 compounds showed that they could play a role in electrical catalytic activity on aqueous solution with NO2-. Besides, the Compounds 1-8 worked in degradation of organic dystuff methylthionine chloride through photocatalytic degradation. What’s more, fluorescence of Compounds 9 and 10 are studied at room temperature and the findings showed that Compound 9 and 10 are both equipped with the potential of becoming luminescent material. |
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