Polynuclear vanadium complexes

POLYNUCLEAR VANADIUM COMPLEXES AND ATTEMPTS TO OBTAIN V02+-Cu2+ BRIDGED POLYMERS... 

The great recent development in electrochemical techniques will certainly be helpful for the study of redox processes of a metal which can occur in so many oxidation states. Multinuclear NMR spectrometers will allow increased use of 51V resonance as a routine method for the characterization of complexes in solution. Other recent developments are the study of polynuclear complexes, metal clusters (homo and hetero-nuclear) and mixed valence complexes, and it can be anticipated that these topics will soon become important areas of vanadium coordination chemistry, although the isolation of compounds with such complex... 

Another example of a complicated polynuclear complex is an octanuclear basic benzoate containing four vanadium(IU) and four zinc(II) atoms [VZn0(02CPh)3(THF)]4-2THF.27D The crystal structure shows that the distances between these four vanadium atoms are just below 3 A and therefore some V—V bonding may occur. 

Some examples of polynuclear polymeric metal arene complexes, obtained by cryosynthetic reactions from tin, titanium, vanadium, chromium, and molybdenum, are represented [202,542,543]. However, the preparative possibilities of such syntheses are not yet clear [201,202]. 

The compound [VCl3(terpy)] is a paramagnetic, octahedral complex formed in the reaction of VCI3 (100) or [VCl3( BuNC)3] (408) with terpy. A bis(terpy)vanadium(III) complex is presumably the product of oxidation of [V(terpy)2] (49). A red polynuclear complex is formed from the reaction of aqueous vanadium(III) solutions with one equivalent of terpy (49). 

Vanadium compounds of a low oxidation state are reductants, while vanadium(V) compounds are oxidants. In aqueous solutions V aq, V aq, VO ", and VOf ions exist, but also numerous complexes and polynuclear complexes. 

Pajdowski, L. (1963b) Vanadium(lll) hydrolysis. Part 11. Equilibria in a system of mono-and polynuclear complexes. Rocz. Chem., 37, 1363-1376. 

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