Dithiocarbamate and xanthate

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. 

The in vivo antitumor and trypanocidal effects of dimeric [Irn2(CH3COO)4(L)ra]° (L = classical organic antimalarial drugs, n= 1, 2) are reported.494 The dimeric complexes are characterized by IR spectroscopy. Further studies of monomeric Ir11 complexes, IrnL2, where L = alkyl or aryl dithiocarbamates and xanthates, reveal no clear relation between antitumor and antitrypanosomal actvities.495 Structure-activity data for the Ir11 complexes is presented. 

The in vitro trypanocidal and antitumor activities of lfr(cot)L], cot = cyclotetraene, derivatives of dithiocarbamates and xanthates, have been investigated.700 The Ir complexes were characterized by IR spectroscopy, and MO calculations (Hiickel) were performed on the ligands. Similar studies were performed on [Ir(nbr)L], nbr = norbornadiene, L = derivatives of alquil and aryl xanthates 701 and also on [Ir2(cod)2L]X2, where L = 2-hydroxystilbamidine, X = C1, N03, C104, BPh4, and [Ir(cod)L2 ]X, where L = benznidazole, R0-2516, nifurtimox, niridazole. The complex [Ir2(cod)2(2-hydroxystilbami-dine)](BPh4)2 showed the highest activity, as studied by optical microscopy of rats kidneys. 

A term applied to a class of organic accelerators with a very fast and powerful accelerating action examples are the thiuram disulphides, dithiocarbamates and xanthates. See TMT, ZDC and ZIX. 

Thiuram accelerators break down into the corresponding dithiocarbamate before becoming active. There is thus a delay in the onset of vulcanisation. Thiurams can be used over a wide range of sulphur systems. They can behave as system activators when used in combination with thiazoles, whilst acting as retarders for dithiocarbamate and xanthate systems. 

Dithiocarbamates and xanthates form particularly stable, neutral complexes with Cu(II), Cd(II) (and also Ni, Hg, Pb), which are membrane permeable and increase the apparent bioaccumulation of these metals [13]. In the series of sulfoxine, oxine, and chloroxine, the hydrophobicity of the neutral and the charged form, as well as of the Cu complex, increases. While the sulfoxine is not hydrophobic and does not modulate copper toxicity [220], the Cu-oxine complex is hydrophobic with an octanol-water partition constant, log Kok, of 1.7 [221] or 2.6 [222]. Chloroxine can be assumed to be even more hydrophobic, but so far its influence on uptake and toxicity has not been investigated. Uptake of Cu2+ into unilamellar liposomes was increased in the presence of 8-hydroxy-chinoline, and decreased again after adding HA [223],... 

Values of the normalized bite b and the twist angle 8 for these complexes are given in Table 14. In sharp contrast to other tris(chelate) complexes, it is very clear that 8 is not a simple function of b. In all cases 8 is lower than predicted, and in many cases the trigonal prism with 8 = 0° is observed. These dithiolate ligands are clearly different from other bidentate ligands, even other sulfur donors such as MeSCH=CHS, dithioacetylacetonate, dithiooxalate, dithiophosphates, dithiocarbamates and xanthates. 

The (IsQ-coordinated species [Mo(CO)3(py)3] prepared from [Mo(CO)6] and pyridine is useful for the synthesis of various jr-allyl molybdenum compounds (68JOM(13)Pl, 970M5365). The 3-allyl complexes [( 3-allyl)Mo(CO)2Br(py)2] form [( 3-allyl)Mo(CO)2(S,S)(py)] with the anionic S,S-donors, dithiocarbamates and xanthates of sodium and potassium, M (S,S) (81JOM(218)185). [( 3-C3H5)Mo(CO)2(py)2Br] (68JO M(14)375) with thallium hexafluorophosphate in acetonitrile gives... 

Reactions of diaryliodonium salts with various organochalcogen anions led to the arylchalcogen derivatives. (Table 5.7) The anions of sulfur compounds afford generally the 5-aryl derivatives. Sometimes the intermediate iodanes can be isolated. Examples are the reaction of dithiocarbamate and xanthate salts with diaryliodonium. Upon heating, the dithiocarbamate derived iodane afforded the aryldithiocarbamates.133 Thermal decomposition of the xanthate derived iodanes gave mixtures of arylxanthates and diaryldisulfides. ... 

Rate of vulcanization Ultra-accelerators include dithiocarbamates and xanthates. Semiultra-accelerators include thiurams and amines. Fast accelerators are thiazoles and sulfonamides. A medium-rate system is diphenylguanidine. A slow accelerator is thiocarbanilide. 

The anaerobic oxidation of a range of dithiocarbamates and xanthates by inert metal complexes has been shown to proceed by an outer-sphere process, in which the key step involves the formation of a sulfur-centered radical. The standard electrode potential for the Et2NCS2/Et2NCSJ couple is estimated to be 0.425 0.33 V vs. SCE. 

Comparison of sodium diethyl dithiocarbamate and xanthate in the flotation of Pb-Zn ore is given by the following ... 

A whole variety of thiocarbonylthio compoimds have been S5mthesized and used in RAFT polymerization. The initial work was focused to some extent on the use of dithioesters. More recently the range of RAFT agents is expanded to trithiocarbonates, dithiocarbamates, and xanthates. 

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