Iron dimethyldithiocarbamate

Fig. 6 Comparison between the number average molar mass and the relative amount of butanedioic acid in photo-oxidised polyethylenes containing different photoinitiators and stabilisers. The used additives were iron dimethyldithiocarbamate in SGI, iron dimethyldithiocarbamate and 0.8% carbon black in SG2 and iron dimethyldithiocarbamate and nickel dibutyldithiocarbamate in SG3...

SYNONYMS carbamate, dimethylcarbamodithioic acid, iron complex, ferric dimethyl-dithiocarbamate, iron dimethyldithiocarbamate, iron tris (dimethyldithiocarbamate), karbam... 

Dithiocarbamate fungicides consist of metal salts of dimethylthiocarbamate and ethylenebis-dithiocarbamate anions, as shown in Figure 17.5. These fungicides are named in accordance with the metal ion present. For example, the manganese salt of dimethyldithiocarbamate is called maneb, and the zinc and sodium salts are zineb and nabam, respectively. The iron salt of ethylenebisdithio-carbamate is called ferbam, and the zinc salt of this ion is called ziram. These salts are chelates (Section 2.3) in which two S atoms from the ethylenebisdithiocarbamate anion are bonded to the same metal ion in a ring structure. 

The traditional copper fungicides are in fact inorganic copper coordination compounds The still most important group of organic protectant fungicides, the dithiocarbamates, are applied in the form of their metal-coordination compounds. Dimethyldithiocarbamate as the iron complex ferbam and the zinc complex ziram, ethylenebisthiocarbamate as the zinc complex zineb and the manganese complex maneb. 

The first example originates from older work (1) on the mode of antifungal action of dimethyldithiocarbamates. It could be proven that fungitoxicity is not connected with the dimethyldithiocarbamate ion as such or with its iron or zinc complexes used in practice, but with the very special properties of its 1 1 copper complex which is formed from the very minute but ubiquitous amounts of copper present in all natural waters, even in "pure" tap water. 

SYNS AAFERTIS BERCElvLA FERTAM 50 CARBAMATE DIMETHYLCARBAMODITHIOIC ACID, IRON COMPLEX DIMETHYLCARBAMODITHIOIC ACID, IRON(3+) SALT DIMETHYLDITHIOCARBAMIC ACID, IRON SALT DIMETHYLDITHIOCARBAMIC ACID, IRON(3+) SALT EISENDIMETHYLDITHIO-... 

In the mode of action of the dimethyldithiocarbamate, ferbam (30), reduction and the atmospheric re-oxidation of iron also play a role (Owens and Rubinstein, 1964). The end-products of this process are dimethylamine and carbon disulfide. 

Cobalt is well known for its ability to break an oxidatively destructive chain reaction catalysed by another metal (cf. Baur and Preis, 1936). This suggested to the Dutch workers that the iron and copper complexes of oxine, pyrithione, and dimethyldithiocarbamic acid were oxidatively destroying thioctic acid (dihydrolipoic acid) (2.28) which is the essential coenzyme for the oxidative decarboxylation of pyruvic acid. This was confirmed when they found pyruvic acid accumulating in the medium (Sijpesteijn and Janssen, 1959 also personal communications from these authors). The receptor in all three examples is the small molecule (2.28) although, at the time, it caused surprise to find one of such low molecular weight. 

Dimethyldithiocarbamic acid, or DMDC (5.57), is a potent fungicide much used in agriculture as the sodium ( NaDDC ), iron (Termate or ferbam), and zinc ( Zerlate or ziram) salts. Formula (77.75) shows the 1 1 copper complex. 

For further reading on the dimethyldithiocarbamates, see Thorn and Ludwig (1962). Some agriculturalists prefer to use the zinc and iron complexes of... 

Copperas red. See Iron oxide red Copper bichloride. See Copper chloride (ic) Copper, bis (acetate) hexametaarsenitotetra-. See Copper acetoarsenite Copper, bis(dimethyldithiocarbamate)-. See Copper dimethyidithiocarbamate Copper bis (2-pyridinethiol-1-oxide). See Copper pyrithione... 

Synonyms Aafertis Bercema Fertam 50 Carbamate Dimethylcarbamodithioc acid iron complex Dimethylcarbamodithioc acid iron(3+) salt Dimethyldithiocarbamic acid iron salt Dimethyldithiocarbamic acid iron(3+) salt ENT 14689 Ferbam 50 Ferbame Fer-bam, iron salt Ferbeck Ferberk Fermate Fermate ferbam fungicide Fermocide Ferra-dow Ferric dimethyldithiocarbamate Fuklasin Fuklasin ultra Hexaferb Hokmate Iron flowable Iron tris(dimethyldithiocarbamate) Karbam black Trifimgol Tris(dimethyl-carbamodithioato-S,y)iron Tris(dimethyldithiocarbamato)iron Vancide FE95. 

The first report of iron dithiocarbamate chemistry was in 1907, when Delepine (2) detailed the synthesis of the iron(III) tris(dithiocarbamate) complex [Fe(S2CN i-Bu2)3]. Later the dimethyldithiocarbamate complex [Fe(S2. CNMe2)3l (Ferbam) found widespread use as a fungicide (14). Iron(ll)... 

For further reading on the dimethyldithiocarbamates, see Thom and Ludwig (1962). Some agriculturalists prefer to use the zinc and iron complexes of DMDC, principally because of the excellent adhesion to plants which enables the complexes to resist long periods of rain. Others prefer tetramethylthiuram disulphide, which is the disulphide obtained by oxidizing DMDC, and which is slowly reduced to DMDC imder field conditions. 

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