Dialkyldithiocarbamates metal

RG Shelkova. Mechanism Action of Dialkyldithiocarbamates of Metals as Effective Inhibitors of Hydrocarbon Oxidation. PhD (Chem.) Thesis Dissertation, Petrochemical Institute, Moscow, 1990 [in Russian],... 

Some complexes with particularly interesting structures are formed from gold(I) and N, iV-dialkyldithiocarbamates and 0,0 -diisopropyldithiophosphate,277 279 and probably also for dithiophosphinates, prepared according to equation (38). These form dimeric units with approximately linear SAuS linkages, but the dimers are further associated into chains by intermolecular Au Au contacts as shown in Figure 7. When it is considered that the Au—Au distance in metallic gold is 276.8 pm, it is clear that the intramolecular and intermolecular Au—Au distances in these complexes of 276-310 pm and 305-340 pm respectively must involve some bonding interaction,7 and this has been confirmed by Raman spectroscopy.281... 

The chelating S,S-donors, applied in the examined syntheses, are widely represented (see Sec. 2.2.4.5) by alkali metal salts of dialkyldithiocarbamates and alkylxanto-genates (3.144) [310] ... 

Tetraalkylthiuram disulfides, R2NC(S)S-S(S)CNR2, are oxidized forms of the di-alkyldithiocarbamate ions R2NC(S)Sa Thiuram disulfides possess pronounced oxidative properties and can easily oxidize and stabilize polyvalent cations in high oxidation states (Ni(III), Cu(III), Ag(II), etc.) as well as coordinate these metal ions in the molecular form [18,19]. Therefore, it should always be kept in mind that complexation of polyvalent cations with dialkyldithiocarbamate anions can be accompanied by a redox equilibrium of the following type ... 

Metal dithiocarbamates have been investigated as single-source precursors for MOCVD nanosized particles of metal sulfides, such as PtS and PdS,43 PbS,437,4 8 and Bi2S3,439 and tin sulfide thin films.440 In this respect the termochemistry of dithiocarbamates (periodically reviewed441 144) is important. Molybdenum dialkyldithiocarbamates are highly effective antiwear, antiseize, and antifriction additives for lubricating oils,445 and are used as vulcanization accelerators.446... 

Coordination of a hard metal ion, Cr111, to soft S- or Se-donors is regarded as unusual.646 Typical structures of crystallographically characterized compounds ((138)-(142)) are illustrated.647-651 By far the most numerous known mononuclear complexes of this type are those with l,l-dithiolato(l—) ligands, including dialkyldithiocarbamates, xanthates, dithiocarboxylates,... 

The antifungal effect of the 2 1 complex nontoxic in itself, is an unsettled question. According to certain authors, it is converted within the cell into the 1 1 complex. However, this is inconsistent with the fact that the 2 1 complex cannot penetrate the cell with its very low water solubility. According to recent theories, the stabilities of the complexes play the decisive role. The stability of the metal complexes of identical dialkyldithiocarbamates depends on the metal. The order of stability of dimethyldithiocarbamate complexes used as fungicides is, according to Eckert (1957), Mn[Pg.360]

The ajkyl and dialkyldithiocarbamates are important commercially. Some of their heavy metal salts, produced by metathesis from the sodium or ammonium salt solution, are used as accelerators for the vulcanization of rubber (e.g., the zinc salt). 

Diarylamines do not react with carbon disulfide, whereas dialkyl amines readily form dithiocarbamates. However, NjAT-diaryldithiocarbamates can be prepared from metal salts of diarylamines and carbon disulfide (15). They are more stable than dialkyldithiocarbamic acids, eg, N,N -diphenyldithiocarbamic acid [7283-79-6], mp 142°C. Similarly, various metal salts of DPA react with carbon dioxide and an epoxide to give the P-hydroxyalkyldiphenylcarbamates (16). 

Oxidized Metal Dithiocarbamates. One of the most intriguing developments in recent years in the chemistry of CS2 derivatives is the exceptional ability of the N,N -dialkyldithiocarbamate ligand to stabilize complexes in which the metal is in a high formal oxidation state. The... 

Since hydroperoxides play a determining role in the photooxidative degradation of polymers, decomposition of hydroperoxides into more stable compounds, before the hydroperoxides undergo photolytic cleavage, would be expected to provide an effective means of UV protection. Metal complexes of sulfur-containing compounds such as dialkyldithiocarbamates (XIX), dialkyldithiophosphates (XX) and thiobisphenolates (XXI) are very efficient hydroperoxide decomposers even if used in almost... 

However, hydroperoxide decomposers may act by much more complicated mechanisms. Many sulfur compounds, like the thiodipropionate esters (DRTPs) or the metal dialkyldithiocarbamates (MRDCs) are oxidised to sulfur acids (sulfinic, sulfonic and SO3) which are ionic catalysts for the non-radical decomposition of hydroperoxides. The MRDCs are particularly important since, unlike the phosphites, they also contain complex transition metal ions and when M is a transition metal ion e.g. Ni) they are also UVAs. 

Secondary antioxidants work by preventing the formation of free radicals. Some of them will decompose hydroperoxides by a safe reaction before they get the chance to generate fiee radicals. Hydroperoxide decomposers fall into two categories some act by a catalytic mechanism. These include the sulfur-containing acids that are formed by the oxidation of thiodipropionate esters or metal dialkyldithiocarbamates. The last-mentioned, if they contain a transition metal, are also ultraviolet light absorbers. An alternative type of hydroperoxide decomposer acts by a stoichiometric mechanism, namely the phosphite esters. 

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