Dialkyldithiocarbamates

Of the dialkyldithiocarbamates belonging to the second group of dithiocar-bamates, dimethyidithiocarbamates have the highest activity. With an increase of the alkyl group fungitoxity is rapidly reduced. The compounds are prepared by the reaction of dimethylamine with carbon disulfide and alkali hydroxide. The individual active substance can be obtained by the addition of the alkali salt formed. 

The sodium salt of dimethyidithiocarbamate is diram (29), and the ammonium salt is diram-A. Both salts are phytotoxic but can be used for seed treatment. Of this group, too, only the water-insoluble metal salts come under consideration as foliage fungicides. Of these, the iron salt of dimethyidithiocarbamate, ferbam (30), is the most important because it is more stable than the zinc salt, ziram (31). 

In the preparation of ferbam an excess of ferric ions must be avoided, because their oxidising action diminishes the stability of ferbam. The metal salts of 

The excellent fungicidal properties of dithiocarbamates have stimulated research-workers to investigate this area for active substances of improved biological activity, and possibly of higher selectivity. 

Part of this research has been directed towards N,N-dimethylthiocarbamoyl-thioacetic acid (33) and its homologues, which have properties similar to those of auxins and have a systemic antifungal effect (Van der Kerk et at., 1955 Garraway, 1965). 

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Nickel dialkyldithiocarbamates stabili2e vulcani2ates of epichlorhydrinethylene oxide against heat aging (178). Nickel dibutyldithiocarbamate [56377-13-0] is used as an oxidation inhibitor in synthetic elastomers. Nickel chelates of substituted acetylacetonates are flame retardants for epoxy resins (179). Nickel dicycloalkyldithiophosphinates have been proposed as flame-retardant additives for polystyrene (180—182) (see Flame retardants Heat stabilizers). 

Fe " complexes in general have magnetic moments at room temperature which are close to 5.92 BM if they are high-spin and somewhat in excess of 2BM (due to orbital contribution) if they are low-spin. A number of complexes, however, were prepared in 1931 by L. Cambi and found to have moments intermediate between these extremes. They are the iron(lll)-A,A-dialkyldithiocarbamates, [Fe(S2CNR2)3], in which the ligands are ... 

Blue [CrlRxantla] (R = Me, Et, or L-menthyl) complexes have been prepared and characterized (103, 106, 107), and these complexes, together with some of the dialkyldithiocarbamate complexes, show spin-forbidden transitions, E, Ti A2, and T2 2, the last two... 

Peroxide decomposers—These function by reacting with the initiating peroxides to form nonradical products. Presumably mercaptans, thiophenols, and other organic sulfin compounds function in this way [19]. It has been suggested that zinc dialkyldithiocarbamates function as peroxide decomposers, thus giving mbber compounds good initial oxidative stability. 

The reaction of methylene bis(dialkyldithiocarbamates) with [Au(C6F5)(tht)j leads to the complexes [ Au(C6F5) 2 CH2(S2CNR2)2 ] [43] (R = Me, Et, n-Bu, Bz). The NMR resonances of the bridging methylene groups in the complexes are observed at lower field than that in the free ligand and some modification of the C=S stretching is observed. 

The dinuclear dialkyldithiocarbamate precursor [Co2(dtc)5]+ reacted with diamine mustards N,N- and /V,/V -bis(2-chloroethyl)ethylenediamine (bee, dee) and their non-chlorinated analogs yield [Co(dtc)2(diamine)]+.1049 The bee and dee compounds were prepared and tested as potential hypoxia-selective cytotoxins, but did not prove of value as potential bioreductive anticancer drugs, partly due to their redox instability. 

Zinc dithiocarbamates have been used for many years as antioxidants/antiabrasives in motor oils and as vulcanization accelerators in rubber. The crystal structure of bis[A, A-di- -propyldithio-carbamato]zinc shows identical coordination of the two zinc atoms by five sulfur donors in a trigonal-bipyramidal environment with a zinc-zinc distance of 3.786 A.5 5 The electrochemistry of a range of dialkylthiocarbamate zinc complexes was studied at platinum and mercury electrodes. An exchange reaction was observed with mercury of the electrode.556 Different structural types have been identified by variation of the nitrogen donor in the pyridine and N,N,N, N -tetra-methylenediamine adducts of bis[7V,7V-di- .vo-propyldithiocarbamato]zinc. The pyridine shows a 1 1 complex and the TMEDA gives an unusual bridging coordination mode.557 The anionic complexes of zinc tris( V, V-dialkyldithiocarbamates) can be synthesized and have been spectroscopically characterized.558... 

Complexes of zinc dialkyldithiocarbamates with bidentate nitrogen ligands such as 1,10-phen-anthroline have been structurally characterized.563 The related complexes (4,4 -bipyridyl)... 

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

Nickel-copper alloys, 73 518 77 100 Nickel cyanide, 77 112 Nickel dialkyldithiocarbamates, 77 124 Nickel dicycloalkyldithiophosphinates, 77 124... 

The authors describe experiments on six NR compounds commonly used for latex gloves to determine the potential hazards of skin contact with reference to curing compounds and accelerators, including mercaptobenzthiazole and zinc dialkyldithiocarbamates. Simulation methods and the influence of a common hand disinfectant were investigated. In the case of tetramethylthiuram disulphide, it was discovered that decomposition products could be formed on the skin which are not present in the original rubber. 6 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.849747... 

We found that the nucleophilic substitution of PVC with N,N-dialkyldithiocarbamate (R-N-CS-S-, DTC) was feasibly achieved at low temperature as 50-60°C in DMF without accompanied dehydrochlorination (equation 3)( ). ... 

The second important class of accelerators are zinc dialkyldithiocarbamates (XXI). These are more active with faster vulcanization rates than the 2-mercaptobenzothiazole sulfena-mides. Also, activators are not usually needed since the zinc is incorporated into the accelerator molecule. Tetralkylthiuram disulfides (XXII) in combination with activators S... 

Inhibition of Oxidation. Several antioxidants were tested in chloroprene at 45°C. Those which can be classified as mainly suppressors of initiation (I), because of their ability to destroy hydroperoxides—namely, zinc dialkyldithiophosphates, zince dialkyldithiocarbamates, triphenyl-phosphine, and the like—had no inhibiting effect at the 100-p.p.m. level. 

A crystallographic study of MeZnS2CNEt2 (40) revealed that in the crystal phase, this complex exists in the dimeric [MeZnS2CNEt2]2 form. Unfortunately, no clear conclusion could be drawn about the structure of this compound in either the solution or the gas phase. Mass spectra of 40 and related compounds MeZnS2CNMe2 (41) and EtZnS2CNMe2 (42) contained peaks attributed to the M+ of the monomers and to the [Zn(dialkyldithiocarbamate)2] + ions". ... 

V(S2CNR2)3] (R = Me, Et, Prn or Bu ) were obtained by oxidation of VBr2-6H20 with diethylammonium dialkyldithiocarbamates in anaerobic ethanol/triethyl orthoformate.290 Complexes [VL3] and [VCILJ of cyclic substituted dithiocarbamates L (L = piperidino, morpholino, thiomorpholino and V-methylpiperazino) were reported 291 their properties are consistent with bidentate dithiocarbamate. 

MCD spectroscopy has been useful in the location of the spin-forbidden transitions.1019 That the Cr—S bond is comparatively strong has been adduced from the presence of relatively intense molecular ion peaks in the mass spectra of several Cr111 dialkyldithiocarbamates.1020... 

Scheme 2), which acts as a catalyst for the ionic decomposition of hydroperoxides (B-80MI11504, B-81MI11502). Other sulfur compounds known to be active peroxide decomposers are the nickel dialkyldithiocarbamates (3) (B-80MI11505) and the thiol (4) (B-81MI11502). 

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