Vanadium specific derivatives

Although die role of iron in various heme derivatives and zinc in carboxypep-tidase and carbonic anhydrase is dear. Ihere are many instances in which little is known of the function of the trace metal. For example, it has been known for some time that ascidians ("sea squirts") concentrate vanadium from sea water by a factor of a millionfold, but a satisfactory explanation for its role in these animals remains elusive.117 There are many elements that are known to be usefol but for which no specific function has yet been proved. The list of known functions is expanding rapidly, however. 

The chemistry already described is reproduced by numerous ligands that have not specifically been addressed in the previous discussion. The V-salicylidenehydrazides (Scheme 4.18a) and related compounds provide a good example. The structure [76] of a typical complex, represented in Scheme 4.18b, is not very different from that proposed for the solution structures of dipeptide complexes (Scheme 4.17). Interestingly, other similar complexes, based on Schiff base-derived ligands, form dimeric [VO]2 core complexes (Scheme 4.1) via two long ( 2.4 A) VO bonds [2], The cyclic core is not necessary for dimer formation, and a dimer can form via a linear VOV bond [77], These complexes otherwise are not significantly different in their vanadium coordination from that depicted in Scheme 4.18b. 

Other forms of vanadium have been implicated in the stimulation of the plasma membrane vanadate-dependent NAD(P)H oxidation reaction. Decavanadate has been shown to be a more potent stimulator of the vanadate-dependent NADH oxidation activity than added orthovanadate [30,31], Interestingly, decavanadate reductase activity has been found to be an alternative activity of an NADP-specific isocitrate dehydrogenase [32], Diperoxovanadium derivatives have also been shown to be involved in this type of reaction [33,34], Decavanadate may play a role in the biological role of vanadium, as it is found in yeast cells growing in the presence of orthovanadate [8] and is a potent inhibitor of phosphofructokinase-1, the control step of glycolysis, and other metabolic reactions [35],... 

Note added in proof. This statement is no longer correct. The Gmelin-Institut has commenced publication of volumes in the 8th edition of Gmelin s Handbuch der anorganische Chemie specifically concerned with organometallic compounds. The first volume describes the derivatives of vanadium and chromium. 

In comparison with the bio-oils reported in the literature [2, 3], the investigated bio-oil exhibits relatively low contents of sodium (Na), phosphorous (P), calcium (Ca) and potassium (K) (Table 5). These concentrations are far from the gas turbine normal specifications [15], One should take into account however that the cmde bio-oil has not been submitted to any post-treatment. It is important to note the presence of Mg, Fc and Al. In spite of their low concentrations, diese metals have potential to inhibit the corrosion caused by the vanadium contained in PR-derived oil. 

Transition metal oxides derived from ruthenium (RUO2), iron (Fe304), vanadium (V2O5), tin (Sn02), and manganese (Mn02) are widely used in the research and application of pseudocapacitance [76-78]. Oxide materials are known to exhibit multiple oxidation states at specific potentials, and selection of materials with multiple stable states within an electrolyte s potential window allows maximum capacitance to develop. 

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