Vanadium, dithiocarbamate complexes

Inorganic Derivatives.- 1,6-Anhydro 2-chloro-2,4-dideoxy-4-(diphenylphosphoryl)-P-D-glucopyranose, the P-in-the-ring sugar analogues (27) and (28)," the natural arsenic-containing riboside (29), methyl 4,6-0-benzylidene-3-deoxy-3-C-triphenylstannyl-a-D-altropyranoside, two isomeric chromium(III) complexes with 1,3,5-triamino-1,3,5-trideoxy-cw-inositol in the one structure, the vanadium(in) complex (30),and the platinum(Il)-dithiocarbamate complex (31). ... 

Another widely utilized method involves the oxidative-addition of thiuram disulhdes to metal centers (Eq. 15) a reaction that has been reviewed by Victoriano (25, 170). Dithiocarbamate complexes of a number of transition metals can be prepared via this method, with examples at vanadium (171-173), molybdenum (174-180) and tungsten (181-183) being particularly prevalent. 

For example, addition of a range of thiuram disulfides to the vandium(II) complex, [VCl2(thf)2], yields vanadium(lV) bis(dithiocarbamate) complexes, [VCl2(S2CNR2)2] (R = Me, Et R2 = CsHio, C4H8O) (Eq. 16) (173). 

The first examples of vanadium dithiocarbamate complexes were the eight-coordinate vanadium(IV) species [V(S2CNR2)4] prepared in the late 1960s by... 

Figure 62. Structural representations of vanadium tris- and tetralds(dithiocarbamate) complexes.

Vanadium(III) complexes, 473 adenine, 475 alcohols, 478 amides, 474, 480 amines, 474 amino acids, 484 ammonia, 474 aqua, 477 arsines, 476 azide, 475 bipyridyl, 475 bromides, 483 carboxylates, 479 catecholates, 478 chlorides, 482 complexones, 485 cyanides, 474,476 (Wethyl sulfoxide, 480 dioxygen, 478 dithiocarbamates, 481 dithiolates, 481 dithiophosphinates, 481 ethers, 478... 

Some thiolate metal complexes, unlike the oxygen complexes referred to above are powerful antioxidants (see Chapter 1) and undergo inversion to prooxidant metal ions in sunlight. The iron, manganese, cobalt, vanadium and cerium dithiocarbamates (II) are typical examples of such restrained prooxidants. 

Figure 63. Examples of vanadium(V) tris(dithiocarbamate) imido complexes.

The vanadium(V) oxo complex, [VO(S2CNMe2)3] (714), has been shown to sensitize the polymerization of styrene when irradiated at X 365 nm (715). A spectroscopic analysis shows that initiation occurs primarily through loss of a dithiocarbamate radical via an intramolecular photoredox reaction, with [VO(S2CNMe2)2] being the final photoproduct. The rate of polymerization is proportional to the square root of [VO(S2CNMe2)3] concentration. 

Closely related are vanadium-copper complexes [VCu4(p -S>4(S2CN C4HgO)4 (SPh) ] n = 1-3) (Fig. 236), in which copper centers are linked by sulfido bridges to vanadium, and each copper carries either a dithiocarbamate or thiolate ligand (700,1747,1748). Vanadium-51 NMR studies suggest that in solution the different complexes are in equilibrium with one another. 

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