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• 266339-51-9 tris(maltolato)vanadium(III) 
• 118-71-8 Maltol 

Relevant academic research and scientific papers

Reaction chemistry of BMOV, bis(maltolato)oxovanadium(IV) - A potent insulin mimetic agent

The reaction chemistry of the potent insulin-mimetic agent bis(maltolato)oxovanadium(IV) (abbreviated BMOV or VO(ma)2) is reported. VO(ma)2 (log K1 = 8.80(2), log K2 = 7.51 (2), log β2 = 16.31(3)) has a rich coordination chemistry, forming a number of V(IV) and V(V) derivatives. In aqueous solution it is slowly oxidized by molecular oxygen to [VO2(ma)2]- (log K1 = 7.5(1), log K2 = 6.2(1), log β2 = 13.7(1)); in alcohols a variety of V(V) analogs VO(OR)(ma)2 (R = CH3, C2H5, i-C3H7) are formed by aerial oxidation. All these vanadate complexes can be interconverted by reaction with the appropriate alcohol or water. In addition, the six-coordinate V(IV) pyridine adduct VO(ma)2py can be formed and this undergoes oxidation to V(V) complexes much more slowly, demonstrating that a vacant coordinate site is required for the coordination of O2 to VO(ma)2 before inner-sphere oxidation can take place. 51V NMR and electrochemistry have been studied as a function of pH; a complete study of the aqueous chemistry of VO(ma)2 and [VO2(ma)2]- has been undertaken because the oral activity of VO(ma)2 as an insulinmimetic may be related to the chemical properties of the two compounds in water. Oral gavage studies in STZ-diabetic rats have been performed which showed that the intact complex is required for activity and that the presence of a biologically compatible reducing agent, ascorbic acid, neither interferes with nor augments the insulin-mimetic effect of VO(ma)2. The X-ray structures of VO(ma)2 and the cis-VO2 compound K[VO2(ma)2]·H2O have been determined; crystals of VO(ma)2 [BMOV] are monoclinic, P21/n, a = 7.366(1), b = 12.759(2), c = 13.190(1) A?, β = 97.31(1)°, Z = 4, and those of K[VO2(ma)2]·H2O are monoclinic, P21/n, a = 7.1841(9), b = 12.196(1), c = 17.147(1) A?, β = 96.64(1)°, Z = 4. The structure of VO(ma)2 was solved by direct methods and that of K[VO2(ma)2]·H2O by the Patterson method. The structures were refined by full-matrix least-squares procedures to R = 0.076 and 0.033 (R(w) = 0.075 and 0.034) for 1078 and 3232 reflections with 1 ≥ 3σ(I), respectively. VO(ma)2 forms a square pyramid with the O4 set from the two maltolato ligands in the base and the vanadyl V = O apical. [VO2(ma)2]- is roughly octahedral with a cis-[VO2]+ unit being completed by two ma- ligands. The macroscopic structure is a chain with six-coordinate K+ ions linking adjacent [VO2(ma)2]- units through coordination to the chelating ligand O atoms and water molecules.

Vanadium speciation by XANES spectroscopy: A three-dimensional approach

A library of X-ray absorption near-edge structure (XANES) spectroscopic data for VV, VIV and VIII complexes with a broad range of biologically relevant ligand has been used to demonstrate that three-dimensional plots of key XANES parameters (pre-edge and edge energies; pre-edge and white line intensities) can be used for the prediction of V oxidation states and coordination numbers in biological or environmental matrices. The reliability of the technique has been demonstrated by re-analysis of the published XANES data for a VV-dependent bromoperoxidase.

Insulin-enhancing vanadium(III) complexes

Simple, high-yield, large-scale syntheses of the V(III) complexes tris(maltolato)vanadium(III), V(ma)3, tris(ethylmaltolato)vanadium(III), V(ema)3, tris(kojato)vanadium(III) monohydrate, V(koj)3·H2O, and tris(1,

A MAGNETIC RESONANCE IMAGING METHOD USING VANADYL-BASED CONTRAST AGENTS

A new, clinically applicable magnetic resonance imaging (MRI) method has been developed for in vivo imaging of a population of cells in a subject based on a class of paramagnetic divalent vanadyl-based contrast agents. The method includes administering to a subject a VO2+-based contrast agent and monitoring distribution of the VO2+-based contrast agent in the subject using magnetic resonance imaging.