A series of 11 oxovanadium(V) complexes mimicking the active site of vanadium haloperoxidases have been investigated by (51)V magic angle spinning NMR spectroscopy and density functional theory (DFT). The MAS spectra are dominated by the anisotropic quadrupolar and chemical shielding interactions; for these compounds, C(Q) ranges from 3 to 8 MHz, and delta(sigma) is in the range 340-730 ppm. Th...

Bis(peroxo)vanadium(V) complexes are widely investigated as anticancer agents. They exert their antitumor and cyctotoxic effects through inhibition of tyrosine phosphatases and DNA cleavage, respectively. The latter process remains poorly understood. The mechanism of DNA cleavage by NH(4)[(phen)V(O)(eta(2)-O(2))(2)] (phen = 1,10-phenanthroline) was investigated. Kinetic studies on DNA cleavage ...

The oxovanadium(IV) complexes LVO and L'VO (L = dianion of 5,14-dihydro-6,8,15.17tetramethyldibenzo[b.i][l,4.8,ll]tetraazacyclotetradecine. H2L. and L' = dianion of 5.14-dihydro-6,15-dimethyl-8,17-diphenyldibenzo[b,i][l,4,8,1 l]tetraazacyclotetradecine, H2L') are redox active as indicated by cyclovoltammetric measurements and confirmed by preparative methods: Reversible oxidation to the corresp...

Macrocyclic Schiff base ligands (HDAA) and (EDAA) have been synthesized by condensation of Hydrazinedihydrochloride and Ethylenediamine with acetyl acetone respectively in 1:1 molar ratio in ethanolic solution. Further the vanadium complexes were synthesized by refluxing ligands with [VO(acac)2] in1:1 molar ratio in ethanolic medium. The microanalytical analysis have been obtained and UV, IR, H...

the possibility of application of 4-nitrocatechol (4-nc) - tetrazolium salt - organic solventsystems for liquid-liquid extraction-spectrophotometric vanadium (iv and v) speciation wasstudied. six commercially available tetrazolium salts (2,3,5-triphenyltetrazolium chloride (ttc),3-(2-naphtyl)-2,5-diphenyltetrazolium chloride (tetrazolium violet, tv); 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetra...

Two new vanadium oxide compounds, which contain interlamellar transition metal complexes bound to vanadium oxide sheets, were synthesized hydrothermally. The crystal structure of each reveals unusual coordination geometries and interlayer bonding. [Ni(2,29-bipyridine)]2[V12O32] (1) was prepared from the reaction of V2O5, NiO, H2O and 2,29-bipyridyl in the molar ratio 4:8:3312:0.5. The isomorpho...

Given the number of applications surrounding early transition metal cyclopentadienyl sandwich complexes, the paucity of vanadocene research is truly remarkable. This is even more surprising given their potential application as potent antitumor agents,1 paramagnetic medical MRI shift reagents,2ab Ziegler-Natta catalysts,3ab and building blocks for novel magnetic materials.4 Obviously, one of the...

Various combinations of density functionals and pseudopotentials with associated valence basis-sets are compared for reproducing the known solid-state structure of [V 2O 2(OO) 2 l-lact 2] (2-) cis . Gas-phase optimizations at the B3LYP/SBKJC level have been found to provide a structure that is close to that seen in the solid state by X-ray diffraction. Although this may result in part from erro...

The interaction between an RNA model phosphodiester and oxovanadate complexes results in a purely hydrolytic cleavage of a phosphodiester bond under physiological pH and temperature: a comparison of the rate-pH profile with the species distribution diagram indicates that the negatively charged tetravanadate [V(4)O(12)](4-), which forms at toxic vanadium levels, is the hydrolytically active spec...