Dithiocarbamates metal

Photoelectron spectroscopy of metal dithiocarbamate, xanthate and dithiophosphate complexes. 

By using an alkali-metal hydroxide in situ as a proton acceptor, the alkali-metal dithiocarbamate salts, having various degrees of hydration, may be obtained (17). 

The second type oiPd lV) andPt(/F) complexes have the general stoichiometry M(R2C fc)3X 117). These compounds are isostructural with Ni(Bu2rftc)3Br 118). However, in contrast to the preparation of the latter complex, the former complexes cannot be obtained by the direct halogenation of the divalent metal dithiocarbamates, so other preparative routes, as given in Table 1 must be followed. 

The structural chemistry of some metal dithiocarbamates, i.e. systematics, coordination modes, crystal packing, and supramolecular self-assembly patterns of nickel, zinc, cadmium, mercury,363 organotin,364 and tellurium,365 366 complexes has been thoroughly analyzed and discussed in detail. Supramolecular self-assembly frequently occurs in non-transition heavier soft metal dithiocarbamates. Thus, lead(II),367 bismuth(III)368 zinc,369 cadmium,370 and (organo)mercury371 dithiocarbamates are associated through M- S secondary bonds, to form either dimeric supermolecules or chain-like supramolecular arrays. The arsenic(III)372 and antimony(III)373 dithiocarbamates are... 

Reverse reactions, in which the disulfides are reduced and S—S bond breaking takes place, are also possible. So thiuram disulfide reacts with elemental Cu or Ag yielding the metal dithiocarbamates, and (109) can be oxidized with thiuram disulfide to (110) and (111) to (112). 

The second general method for making polymer materials photo-chemically degradable is to mix a radical initiator into the polymer. Once carbon-based radicals have formed, the chains degrade by the autoxidation cycle (Scheme 2). Numerous radical initiators have been investigated, and a partial list includes metal dithiocarbamates,8 metal oxides (e.g., Ti02, ZnO, CuO), metal chlorides (e.g., LiCl, FeCl3), M(acac) complexes, M (stearate), complexes, benzophenone, quinones, and peroxides.1,2... 

Four main types of antioxidants are commonly used in polypropylene stabilizer systems although many other types of chemical compounds have been suggested. These types include hindered phenolics, thiodi-propionate esters, aryl phosphites, and ultraviolet absorbers such as the hydroxybenzophenones and benzotriazoles. Other chemicals which have been reported include aromatic amines such as p-phenylenediamine, hydrocarbon borates, aminophenols, Zn and other metal dithiocarbamates, thiophosphates, and thiophosphites, mercaptals, chromium salt complexes, tin-sulfur compounds, triazoles, silicone polymers, carbon black, nickel phenolates, thiurams, oxamides, metal stearates, Cu, Zn, Cd, and Pb salts of benzimidazoles, succinic acid anhydride, and others. The polymeric phenolic phosphites described here are another type. 

Diorgano tellurium dihalides and alkali metal dithiocarbamates react to produce diorgano tellurium bis[dithiocarbamates]4 8. 

Similarly, nickel(ll) and copper(ll) transition metal dithiocarbamate ion-pair receptors 21, containing amide-and crown ether-recognition sites, bind alkali metal cations and various anions. The sandwich K+ complex of the nickel(ll) receptor cooperatively enhanced the binding of acetate anion, while the copper(ll) receptor electrochemi-cally can sense anions and cations via perturbation of the copper(n)/copper(m) dithiocarbamate redox couple <2002JSU89>. 

Dithiocarbamates are normally prepared as alkali metal salts by the action of primary or secondary amines on CS2 in the presence of, say, NaOH. The zinc, manganese, and iron dithiocarbamates are extensively used as agricultural fungicides, and zinc salts as accelerators in the vulcanization of rubber. Alkali metal dithiocarbamates are usually hydrated and are dissociated in aqueous solution. When anhydrous, they are soluble in organic solvents in which they are associated. 

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... 

Evolved gas applications are widespread and diverse. Coordination chemistry has been considerably enhanced by thermal analysis studies of a wide range of metal complexes. The emphasis of these studies has been to derive thermal decomposition mechanisms for such metal complexes. Prior to the development of EGA, such reported mechanisms were suspect because the volatile decomposition products and the solid intermediates were, in general, not identified directly but characterized indirectly on the basis of mass loss data. This procedure is flawed when multiple gaseous decomposition products and nonstoichiometiic intermediates are involved. The thermal analysis of one such group of metal complexes, the metal dithiocarbamates, has been extensively studied and reviewed by Hill and Magee and these are definitive studies in this field. 

Hill, J.O. Magee, R.J. The thermochemistry of metal dithiocarbamate complexes and related compounds. Rev. Inorg. Chem. 1981, 3, 141-197. 

By taking advantage of the different stabilities of individual metal dithiocarbamates, it is possible to use ehloroform solutions of the relatively less-stable metal dithiocarbamates for the extraction of the metals which give more stable complexes [103-105]. In determining copper, for example, the colourless chloroform solution of lead diethyldithiocarbamate, Pb(DDTC)2, is used as the reagent. In this way the selectivity of metal reactions with dithiocarbamates may be enhanced. 

In lubricating compositions, these compounds show excellent antioxidant synergy with aromatic amines such as alkylated diphenylamines [43] and sulphur compounds such as metal dihydrocarbyl dithiophosphate, a metal dithiocarbamate, sulphurised olefins, alkyl and aryl sulphides, alkyl and aryl polysulphides, sulphurised carboxylic acid esters, sulphurised alkylphenols, reaction product of an olefin and sulphurised alkylphenol, and phosphosulphurised terpenes or mixtures thereof [43],... 

Some of the most powerful uv stabilisers belong to the class of peroxide decomposing preventive antioxidants and it has been suggested that the mechanism of this type of uv stabiliser is not distinguishable from their behaviour as thermal antioxidants although all peroxide decomposers do not behave as uv stabilisers (11). Of paramount importance in the peroxide decomposer -uv stabiliser class are the metal dithiocarbamates (III) (9,22,23,24) the dithiophosphates (IV) (11,24) and the... 

Marshall, 1977). Fortunately, the active substances themselves are not persistent on the plant. Finally, it is important to keep the ETU content of the preparations to a minimum. Of the metal complexes, the coordination complex of zinc and manganese, mancozeb, is the most stable therefore, the preparations of this active substance contain the smallest amount of ETU (Blazquez, 1973). The potentiation of the activity of metal dithiocarbamates may allow the levels of ETU to be reduced by permitting a reduction in the amount of dithiocarbamate needed to control a fungal pathogen. Clifford and Bruyns-Haylett (1978) reported that zineb 1 1 complex with 2-(2-aminoethylamino)ethanol was shown to be more active than zineb in greenhouse and field trials against Plasmopara viticola. 

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