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Hydrothermal Syntheses, Crystal Structures, and Magnetic Properties of Inorganic−Organic Hybrid Vanadium Selenites with Zero- to Three-Dimensional Structures:  (1,10-Phenanthroline)2V2SeO7, (2,2‘-Bipyridine)VSeO4, (4,4‘-Bipyridine)V2Se2O8, and (4,4‘-Bipyridine)2V4Se3O15·H2O

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posted on 23.10.2003, 00:00 by Zhimin Dai, Zhan Shi, Guanghua Li, Dong Zhang, Wensheng Fu, Haiying Jin, Wei Xu, Shouhua Feng
A family of inorganic−organic hybrid vanadium selenites with zero-, one-, two-, and three-dimensional structures, (1,10-phen)2V2SeO7, (2,2‘-bipy)VSeO4, (4,4‘-bipy)V2Se2O8, and (4,4‘-bipy)2V4Se3O15·H2O (where phen = phenanthroline and bipy = bipyridine), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Different bidentate organodiamine ligands and reactant concentrations were used in the four reaction systems, which are responsible for the variety of structural dimensions of the compounds. (1,10-phen)2V2SeO7 crystallizes in a monoclinic system with space group P21/n and cell parameters a = 8.6509(3) Å,b = 7.8379(2) Å, c = 34.0998(13) Å, β = 91.503(2)°, and Z = 4. (2,2‘-bipy)VSeO4 crystallizes in a monoclinic system with space group C2/c and cell parameters a = 17.0895(12) Å, b = 14.7707(10) Å, c = 11.7657(8) Å, β = 131.354(3)°, and Z = 8. (4,4‘-bipy)V2Se2O8 crystallizes in a triclinic system with space group P1̄ and cell parameters a = 7.1810(10) Å, b = 10.8937(13) Å, c = 11.1811(15) Å, α = 115.455(3)°, β = 107.582(3)°, γ = 91.957(4)°, and Z = 2. (4,4‘-bipy)2V4Se3O15·H2O crystallizes in a monoclinic system with space group Pc and cell parameters a = 7.9889(9) Å, b = 7.8448 Å, c = 23.048(3) Å, β = 99.389(4)°, and Z = 2. (1,10-phen)2V2SeO7 has an isolated structure, (2,2‘-bipy)VSeO4 has a chain structure, (4,4‘-bipy)V2Se2O8 has a layered structure, and (4,4‘-bipy)2V4Se3O15·H2O has a framework structure. The chains are constructed from VO4N2 octahedra and SeO3 pyramids, laced by organic ligands (2,2‘-bipy). The layers consist of vanadium selenite chains [(VO)2(SeO3)2], linked by 4,4‘-bipy molecules. The framework is composed of vanadium selenite sheets [V4Se3O16], pillared by 4,4‘-bipy molecules. All of the compounds are thermally stable to 300 °C, and the magnetic susceptibilities confirm the existence of tetravalent V atoms in the antiferromagnetic (4,4‘-bipy)V2Se2O8 complex and mixed tetravalent and pentavalent V atoms in the paramagnetic complex (4,4‘-bipy)2V4Se3O15·H2O.