Since insulin-dependent diabetes mellitus (IDDM), which causes many severe secondary complications, is characterized by hyperglyceria due to absolute deficiency of insulin, the diseases is controlled by daily injection of insulin. Therefore, the development of insulin replacements of mimetics upon oral administration is an important investigation. Recent studies indicate that vanadium, which is...

Two novel vanadium(III) complexes: V(dipic)(Hbdc)(H2O)2 (1) and [V2(dipic)2(H2btec)(H2O)4]·2H2O (2) (H2dipic = 2,6-pyridinedicarboxylic acid, H2bdc = 1,3-benzene-dicarboxylic acid, H4btec = 1,2,4,5-benzenetetracarboxylic acid) are synthesized by the reaction of V2(SO4)3, 2,6-pyridinedicarboxylic acid and 1,3-benzene-dicarboxylic acid (for 1) or 1,2,4,5-benzenetetracarboxylic acid (for 2) under ...

A new chromophoric reagent, 2-ketobutyric acid thiosemicarbazone (KBAT) has been used for the simultaneous determination of iron, copper and vanadium. KBAT forms yellowish-green and blue complexes with iron (II) and copper (II) respectively at pH 6.5 and a yellow complex with vanadium (V) at pH 5.5. Calibration graphs for the individual determinations by second derivative spectrophotometry were...

A series of mixed alkoxyalkoxo chloro complexes of vanadium(V), [VOCl2(OCH2CH2OR)]2 (R = Me, Et, iPr, Bz), [VOCl2(OCMe2CH2OMe)]2 and [VOCl2(OCH2(cyclo-C4H7O)]2, were synthesised and characterised. The title compounds can be obtained either from VOCl3 and the alkoxyalcohols by HCl elimination or from the corresponding lithium alkoxides and VOCl3 by salt metathesis reaction. X-Ray diffraction stu...

In the present paper [VO(acac)2] reacts with an equimolar amount of tridentate dibasic ONO donor hydrazone ligand derived from the condensation of benzoyl hydrazine with either 2hydroxyacetophenone (H2L 1) or its para-substituted derivatives (H2L 2) (general abbreviation H2L), in the presence of excess amount of salicylaldehyde (Hsal) in methanol under aerobic conditions producing the mixed-lig...

Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S.BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity.

The photo-induced substitution of a CO ligand in Cp*Ta(CO)4 (1) has been used to pre­ pare a series of Cp*Ta(CO)3L (2) complexes, in which the two-electron ligand L includes, e.g., isonitriles, sulfanes, cyclic ethers, phosphanes and pyridines. The complexes (2a-y) were characterized by their v(CO) frequencies and their ’H and 13C NMR spectra, and were compared if possible with the correspondin...