| Molybdate(Ⅳ/Ⅴ) complexes with nitrilotriacetic acid (H3nta) was isolated as [Mo3O(OH)3(Hnta)3]Cl·3H2O (1), K4.5(NH4)1.5[Mo2O4(Hnta)2][Mo2O4(nta)2]·5.5HO (2), (NH4)4[Mo2O4(nta)2]·7H2O (3) in different pH values, which have been characterized by spectroscopic and structural analyses. Moreover, polytelluromolybdates and polyvanadatomolybdate were also synthesized and characterized as (NH4)6[TeMo6O24]·7H2O (4), (NH4)6[TeMo6O24]·Te(OH)6·7H2O (5), (Imi)6[TeMo6O24] (6),(Imi)2(NH4)4[TeMo6O24]··2H2O (7) and (n-C4H9NH3)2(NH4)[VMo12O40]·3(n-C4H9NH2)·4H2O (8).The main results are as follows:1. Complex 1 was synthesized from H3nta and K2MoO4 in the existence of excess strong reducing agent. The complex contains a trimolybdenum center with metal-metal bond.2. Complexes 2 and 3 are dinuclear molybdenum complexes with metal-matal bond. Mo is coordinated by twoβ-carboxy oxygens and a nitrogen atom of nta ligand, forming stable five-member ring, while uncoordinatedβ-carboxylic acid group remains uncoordinated and forms strong hydrogen bond in 2. Similarly, uncoordinatedβ-carboxy group in complex 3 is deprotonated.3. In the study the catalysis of MoTeO for the selective oxidation of propane to acrolein molybdenum, (NH4)6[TeMo6O24]·7H2O (4) and (NH4)6[TeMo6O24]·Te(OH)6·7H2O (5) are served as molecular precursor of MoTeO catalysts. We have also isolated and characterized MoTeO complexes with imidazol: (Imi)6[TeMo6O24] (6) and (Imi)2(NH4)4[TeMo6O24]·2H2O (7) to improve the metal's environment. In addition, we have isolated and characterized a Keggin structure compound (n-C4H9NH3)2(NH4)[VMo12O40]·3(n-C4H9NH2)·4H2O (8) containingⅤand Mo metal atoms. |
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