Vanadium complexes electrochemistry

This chapter primarily covers studies of the electrochemistry of vanadium, which have appeared in the literature during the period 1985-2005. The material is organized on the basis of the oxidation state of the starting complex and is not meant to be an exhaustive review. Cyclic voltammetry (CV) studies outnumber other methods of electrochemistry for the study of vanadium complexes, and redox potentials will be reported as referenced to the Cp2Pe /+ couple in the appropriate solvent except as noted [1]. 

Bonadies, J.A. and C J. Carrano. 1986. Vanadium phenolates as models for vanadium in biological systems. 1. Synthesis, spectroscopy, and electrochemistry of vanadium complexes of ethylenebis[(o-hydroxyphenyl)glycine] and its derivatives. J. Am. Chem. Soc. 108 4088 1095. 

Congeneric Nb species are known [4]. A (trimpsi)V(NO)(CO)2 complex (trimpsi = BuSi(CH2PMe2)3) has been reported [5] which undergoes a reversible oxidation to the cationic V(0) complex at —0.74 V versus Cp2Fe/CH2Cl2 and a second, irreversible oxidation at 0.61 V. More highly reduced complexes of vanadium have been prepared, but their electrochemistry has evidently not been explored. The electrochemical synthesis of CpV(CO)4 from a vanadium anode, cyclopentadiene, and 115 bar of CO at 100 °C in DMF has been reported [6]. 

A second type of mechanism would be the reductive or oxidative demetallation of Intermediate metalloporphyrlns, allowing nickel and vanadium to complex. From the electrochemistry of porphyrins, and solution studies Involving oxidizing and reducing... 

The electrochemistry of dinuclear vanadium o-A-salicylideneamino-ethylphenyl complexes were investigated.372 Conversion of Viv—Viv dimers to Vv—Vv dimers was reported and serves as a representative model system for oxidation reactions.294 296 A related class of these dinuclear complexes form mixed valence vanadium(IV/V) complexes upon oxidation and exhibit an unusual electron delocalization over the V203 3+ core.310 A V111—Vlv mixed valent, dinuclear bis(salicy-lidene)ethylenediamine (salen) complex underwent multielectron oxidation with dioxygen to yield a Vv—Viv mixed valence complex.302... 

Vanadium(IV) complexes, 487 acetates, 513 acetylacetonates, 504 electrochemistry, 505 ESR spectra, 505 adenine, 568 adipates, 516 alcohols, 502 amines, 489 amino adds, 544 equilibria, 544 ammonia, 489 arsenates, 513 arsenic ligands, 496 arsines, 498 ascorbic add, 502 benzilato, 522 biguanide, 496 binucleating ligands, 561 bipyridyl, 492,494... 

Vanadium, Niobium and Tantalum An entry into Cp 2Ta chemistry has been developed with the reaction of Cp TaCl3PMe3 with LiCp. The complex Cp 2Nb(BH4) provides an appropriate entry into Cp 2NbH3 chemistry,A study of the electrochemistry of Cp2NbCl2 has led to the identification of the one-electron reduction product (Cp2NbCl3NbCp2l and (Cp2NbCl]2 on the way to niobocene. Reactions of mono and dihydrides of Cp2TaH(C0)... 

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