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Synthesis and characterization of two new types of oxovanadium complexes with pyrazole as ligand.
- Source :
- Chinese Science Bulletin; Sep2006, Vol. 51 Issue 17, p2189-2196, 8p, 4 Diagrams, 5 Charts, 1 Graph
- Publication Year :
- 2006
-
Abstract
- At room temperature, two new different oxovanadium complexes with simple pyrazole (C3H4N2) as ligand were synthesized. VO(pz)<subscript>4</subscript>(SO<subscript>4</subscript>)·H<subscript>2</subscript>O (1) (pz: pyrazole) is a mono-nuclear oxovanadium complex with pyrazole as terminal ligands. V<subscript>2</subscript>O<subscript>2</subscript>(μ-pz)(μ-OOSO<subscript>2</subscript>)(μ-OCH<subscript>3</subscript>)(pz)<subscript>4</subscript> (2) is bi-nuclear oxovanadium complex containing three different bridges, which are pyrazolate, sulphate and methoxy, respectively. The two complexes were characterized by IR, elemental analyses, thermal analyses and X-ray diffraction. The crystal structural data of the complexes 1 and 2 are given as follows: Complex 1, orthorhombic, Pna2<subscript>1</subscript>, a =14.547(2) Å, b =10.895(2) Å, c =11.835(2) Å; α=β=γ=90°; V=1875.8(5) ų, Z = 4, R<subscript>1</subscript> = 0.0485, <subscript>w</subscript>R<subscript>2</subscript>= 0.1092. Complex 2, triclinic, P1, a =8.377(2) Å, b =9.928(2) Å, c = 16.527(3) Å, α = 85.54(3)°, δ = 80.92(3)°, γ = 87.92(3)°, R<subscript>1</subscript>= 0.1461, <subscript>w</subscript>R<subscript>2</subscript> = 0.4444. The study of non-thermal kinetic de- composition shows that, for complex 1, the possible reaction mechanisms of the two steps are nucleation and growth n=1/3, and three-dimensional pervasion n=2, respectively, and the kinetic equations may be expressed as da/dT = (A/β)exp(-E/RT){1/3(1-α)[-ln(1-α]<superscript>-2</superscript>} and da/d T = (A/β)exp(-E/RT){3/2(1-α)<superscript>2/3</superscript> [1-(1-α)<superscript>1/3</superscript>]<superscript>-1</superscript>}, respectively; for complex 2, the possible reaction mechanisms of the two steps are chemical reaction, and three-dimensional pervasion n=2, respectively; the kinetic equations may be expressed as da/dT = (A/β)exp(-E/RT)[(1-α)ଡ], and dα/d T = (A/β)exp(-E/RT){3/2(1-α)<superscript>2/3</superscript>[1-(1-α)<superscript>1/3</superscript>]<superscript>-1</superscript>}, respectively. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10016538
- Volume :
- 51
- Issue :
- 17
- Database :
- Complementary Index
- Journal :
- Chinese Science Bulletin
- Publication Type :
- Academic Journal
- Accession number :
- 23653577
- Full Text :
- https://doi.org/10.1007/s11434-006-2085-1