Xanthates, complexes

In the initial formation of the cupric xanthates, soluble xanthate complexes form prior to the precipitation of the cuprous xanthate with the concurrent formation of the dixanthogen (51). The dixanthogen can be separated by virtue of its solubiUty in ether. Older samples of alkah metal xanthates contain some dixanthogen, which is thought to form by the following reaction (33) ... 

Thus, a series of bis-cyclopentadienetitanium(III) dithiocarbamate and xanthate complexes have been prepared by Coutts et al. (49-51) by reaction of the sodium salts of the ligands with [Cp TiJCl (Cp =7r-cyclo-pentadiene) in air-free water under an inert atmosphere the dithiocarbamate complexes are bright-green, and the xanthates are blue. 

Mohamed, A.A., Kani, I., Ramirez, A.O. and Fackler, J.P. Jr (2004) Synthesis, characterization, and luminescent properties of dinuclear gold(I) xanthate complexes X-ray structure of [Au2(nBu-xanthate)2j. Inorganic Chemistry, 43, 3833-3839. 

Wood [127] reported an innovative development of the Barton-McCombie deoxygenation of alcohols allowed to work under tin-free conditions. A trimethylborane-water complex proves to be an efficient reagent for the reduction of xanthates. Complexation of water by trimethylborane induces a strong decrease of O - H bond dissociation energy from 116 kcal/mol (water) to 86 kcal/mol (Me3B-water complex). 

A similar sequence of electrode reactions is proposed for the corresponding xanthate complexes (58, 59). 

Simple Mo xanthate complexes were obtained by the reaction between Mo(II) acetate and the xanthate ligands in inert atmosphere (550, 581a). The red crystalline compounds had the stoichiometry Mo2(EtXant)4 and reacted readily with donor molecules such as tetrahydrofuran (550) pyridine, 4-picoline, and Et3As (581a). A Mo(lI)-acetate type of dimeric structure was proposed (581a) for this molecule and was confirmed by a subsequent x-ray study (550). 

Following the successful synthesis of the aryl xanthate complexes, Chen and Fackler reported on the synthesis and structural characterization of the diamagnetic, monomeric bis(0-2,4,6-trimethylphenylxanthato)palladium(II) complex (117). A typical PdS4 unit was found in this complex in which the shorter S2C-0 bond length [1.330(12) A] compared to the Ph-0 bond length [ 1.439(16)] indicates a certain importance of the S2C=6 resonance form in the structure of the xanthate ligand. 

Reaction of methyldiphenylphosphine with the benzyl xanthate complexes [M(S2COCH2Ph)2] (M = Pd, Pt) in chloroform yields the dithiocarbonato complexes (43). The platinum complex (43 M = Pt) undergoes a variety of reactions in chloroform solution, e.g. treatment with HC1 yields m-[(Ph2MeP)2PtCl2].149... 

Stereochemical Aspects of Metal Xanthate Complexes Molecular Structures and Supramolecular Self-Assembly... 

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