Syntheses and Structures of Oxovanadium (IV) Complexes, HB(pz)₃VO(ph‐acac) · 2H₂O (pz, Pyrazole) and HB(3,5‐Me₂pz)₃VO(ph‐acac) · 2H₂O and V₂O₄[HB(pz)₃]₂ · 2CH₃CN

The reaction of VO(ph‐acac)₂ (ph‐acac=phenyacetylacetonato) with NaHB(pz)₃ (pz=pyrazole) or NaHB(3,5‐Me₂pz)₃ in the solution of MeOH gave oxovanadium (IV) complexes HB(pz)₃VO(ph‐acac) · 2H₂O (1) and HB(3,5‐Me₂pz)₃VO(ph‐acac) · 2H₂O (2), respectively. An oxovanadium complex, V₂O₄[HB(pz)₃]₂ · 2CH₃CN (3), was obtained by the reaction of VOSO₄ · 3H₂O with tri(pyrazolyl)borate sodium in MeOH. The complexes 1, 2 and 3 were characterized by elemental analysis, IR, UV‐Vis, NMR. In particular, the crystals of complex 1 and 3 were determined by X‐ray diffraction. They crystallize in space group P2 ₁/c, a=16.497(5) Å, b=7.6601(19) Å, c=17.199(4) Å, β=107.498(19)°, V=2072.8(9) ų, Z=4, R=0.0371 (I>2σ(I)) for 1; in the monoclinic, space group Pbca, with cell dimensions of a=15.531(2) Å; b=18.007(2) Å; c=10.725(2) Å; V=2999.4(8) ų, Z=4, R= 0.0401(I>2σ(I)) for 3. Structure analyses have shown that complex 1 is a monomeric oxovanadium complexe containing polypyrazolylborate and two lattice water. Complex 3 consists of a V₂O₄(HB(pz)₃)₂ molecule and two free CH₃CN lattice molecules in an unit cell. Both possess a similar coordination mode for the vanadium atom. In addition, luminescence properties and thermal analysis characterization of the complexes also are discussed.

Keywords:

• oxovanadium complexes
• tripyrazolylborate
• crystal structures
• spectral properties

We wish to express our sincere thanks to National Natural Science Foundation of China (No. 20571036), and SRF for ROCS, SEM and Education Foundation of Liaoning Province (No. 05L212) and Japan Society for the Promotion of Science for Postdoc. Grant (2001, 9 – 2003, 9. No: P01072) for financial assistance.