Rhodium, dithiocarbamate complexes

Rhodium(I) and (III) complexes are well known, although there is still some debate about the existence and nature of compounds formulated to contain rhodium(II) dithiocarbamate centers. Relatively little work has been carried out on iridium complexes, although again the +1 and +3 states are both accessible. The +4 oxidation states can also be generated for both metals, and somewhat unusually, rhodium(IV) complexes show far greater stability than their iridium analogues. 

A number of binuclear rhodium(I) complexes are known. When carbon monoxide is bubbled through a diethyl ether suspension of [Rh(S2CN MePh)(NBD)], dimeric [Rh2(CO)2(NBD)(p-S2CNMePh)2] (338) (Fig. 186) results, which is believed to contain two dithiocarbamates (285). 

Craciunescu et al. (1463,1464) examined the antimmor activity of a range of rhodium and iridium tris(dithiocarbamate) complexes. Iridium complexes showed low activity against various tumors and there was also a correlation between this activity and their trypanosomicidal activity against various trypanosoma species in rats. Rhodium complexes showed similar behavior with [Rh(S2CNHPh)3] being most promising. As a result the nephrotoxic effects of the latter were studied by optical and electron microscopy. 

Carbon-based sorbents are relatively new materials for the analysis of noble metal samples of different origin [78-84]. The separation and enrichment of palladium from water, fly ash, and road dust samples on oxidized carbon nanotubes (preconcentration factor of 165) [83] palladium from road dust samples on dithiocarbamate-coated fullerene Cso (sorption efficiency of 99.2 %) [78], and rhodium on multiwalled carbon nanotubes modified with polyacrylonitrile (preconcentration factor of 120) [80] are examples of the application of various carbon-based sorbents for extraction of noble metals from environmental samples. Sorption of Au(III) and Pd(ll) on hybrid material of multiwalled carbon nanotubes grafted with polypropylene amine dendrimers prior to their determination in food and environmental samples has recently been described [84]. Recent application of ion-imprinted polymers using various chelate complexes for SPE of noble metals such as Pt [85] and Pd [86] from environmental samples can be mentioned. Hydrophobic noble metal complexes undergo separation by extraction under cloud point extraction systems, for example, extraction of Pt, Pd, and Au with N, A-dihexyl-A -benzylthiourea-Triton X-114 from sea water and dust samples [87]. 

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