Haloperoxidase-like Compounds: Synthesis, Structure and Properties of Two New Oxidovanadium-Poly(pyrazolyl)borate-Carboxylate Complexes

Two new oxidovanadium (IV) complexes: TpVO(L1) (1) and Tp*VO(pzH*)(L2) (2) [Tp = hydrotris(pyrazolyl)borate, HL1 = 5-methyl-1H-pyrazole-3-carboxylic acid, Tp* = hydrotris(3,5-dimethylpyrazolyl)borate, pzH* = 3,5-dimethylpyrazole, HL2 = 5-phenyl-1H-pyrazole-3-carboxylic acid] have been synthesized and characterized by elemental analysis and IR spectroscopy. The single-crystal structures of the complexes shows that the vanadium ion is in a distorted octahedral environment with a N4O2 donor set in each complex. Additionally, hydrogen bonding interaction exits in both complexes. Interestingly, the molecules of 1 are held together to form a 1D hydrogen bonded polymer along the b axis, whereas complex 2 is a hydrogen bonded dimer. In addition, the catalytic activities of complexes 1 and 2 in bromination reactions in phosphate buffer with phenol red as a trap were evaluated primary by UV/Vis spectroscopy. Furthermore, ab initio calculations of complexes 1 and 2 were performed.