Haloperoxidase-like compounds: Synthesis, structure and properties of two new oxidovanadium-poly(pyrazolyl)borate-carboxylate complexes

Abstract

Two new oxidovanadium (IV) complexes: TpVO(L1)(1) and Tp&z.ast;VO(pzH&z.ast;)(L2)(2) [Tp=hydrotris(pyrazolyl) borate, HL1=5- methyl-1H-pyrazole-3-carboxylic acid, Tp&z.ast;=hydrotris(3,5-dimethyl- pyrazolyl)borate, pzH&z.ast;=3,5- dimethylpyrazole, HL2=5-phenyl-1H-pyra zole-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.©2009 WILEYVCH Verlag GmbH & Co. KGaA.