Several liquid-liquid extraction systems containing vanadium {vanadium(IV) or vanadium(V)}, azoderivative of resorcinol {ADR: 4-(2-pyridylazo)-resorcinol (PAR) or 4-(2-thiazolylazo)-resorcinol (TAR)} and (phenylmethoxibis)tetrazolium salts {MBT: 3,3'-(3,3'-dimetoxy-4,4'-biphenylene)-bis(2,5diphenyl-2H-tetrazolium) chloride (Blue Tetrazolium, BT) or 3,3'-(3,3'-dimetoxy-4,4'-biphenylene)bis[2,5-d...

The toxicity of amyloid-forming proteins can be linked to many degenerative and systemic diseases. Human islet amyloid polypeptide (hIAPP, amylin) has been associated with type II diabetes. Methods for efficient inhibition of amyloid fibril formation are highly clinically important. This study demonstrated the significant inhibitory effects of six vanadium complexes on hIAPP aggregation. Vanadi...

We report the first structures of simple acetate complexes of vanadium(III) formed in aqueous solution. Paramagnetic (1)H NMR spectroscopy titration experiments indicate the formation of two major V(III)/acetate complexes in acidic aqueous solution for acetate/V(III) < or =4, pD 3.50. A novel tetranuclear cluster and a trinuclear cluster have been characterized by X-ray diffraction studies. Mas...

A force field for vanadium-oxos was developed and tested with a variety of complexes with coordination numbers of 5 or 6 and formal oxidations states of +4 or +5 on the metal. Similarly, a semiempirical quantum mechanical method for transition metals was extended to vanadium. In this research soft and hard ligands were studied, as were ligands coordinated through single, multiple, and dative bo...

Oxo- and imido-vanadium(V) metal complexes supported by bis(phenolate)-functionalized N-heterocyclic carbene (NHC) ligands were synthesized structurally identified. In the presence of [(Ph3P)2N]Cl ([PPN]Cl), saturated NHC oxo-vanadium showed activity in coupling CO2 cyclohexene oxide (CHO) into cis-cyclohexene carbonate (cis-CHC). More importantly, complex bearing less electron-donating benzann...

A series of oxovanadium(V) complexes containing amine pyridine(s) phenolate ligands [ONN] (2a-f) have been synthesized in high yields (68-83%) by reacting VO(O(n)Pr)3 with 1.0 equiv. of the ligands in CH2Cl2. These complexes were characterized by (1)H, (13)C and (51)V NMR spectroscopy and elemental analysis. X-ray structural analysis for 2a, 2c and 2d revealed that these complexes adopt a six-c...

in this research some mathematical calculations has been explained on the “ +vo2 +glycylglycine” system and some equations has been deduced to determine the stability constants ofthe equilibrium models including mlh+, ml and ml2h species (while m+ ≡ +2 vo , h2l+ ≡protonated glycylglycine and mlh+, ml and ml2h represent the considered complexes). thecalculations are based on some relations betwe...

The crystal structure of the title compound, [Cr(C8H8NO)3], is isotypic with the vanadium(III) analogue. The asymmetric unit consists of one Cr(3+) cation and three N-methyl-salicylaldiminate anions. The metal cation is octa-hedrally coordinated by three N,O-chelating N-methyl-salicylaldiminate ligands, leading to discrete and neutral complexes. In the crystal, neighbouring complexes are linked...

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resu...

A series of mononuclear V((V)), V((IV)) and V((III)) complexes were investigated by V L-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The spectra show significant sensitivity to the vanadium oxidation state and the coordination environment surrounding the vanadium center. The L-edge spectra are interpreted with the aid of the recently developed Density Functional Theory/...