Manganese complexes, dithiocarbamates

Chemical Name manganese ethylenebis(dithiocarbamate) (polymeric) complex with zinc salt CAS Registry No 8018-01-7 Uses fungicide... 

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. 

Mancozeb is a polymeric mixture of a zinc salt and maneb containing 20% of manganese and 2.55% of zinc (HSDB 1999). Its chemical name is manganese ethylenebis(dithiocarbamate) (polymeric) complex with zinc salt. It may be in the form of a wettable or dustable powder, a suspension concentrate, or dry seed treatment. 

Synonyms Ethylene bis dithiocarbamic acid manganese zinc complex Maneb, zinc enriched Manganese ethylenebis dithiocarbamate complex with zinc salt Manoseb Manzeb... 

Doherty and Manning prepared authentic manganese(ll) dithiocarbamate complexes, [(Ti -C5H4Me)Mn(NO)(S2CNR2)], from the addition of dithiocarbamate salts to [(ri -C5H4Me)Mn(CO)2(NO)][PF6] (Eq. 108), although this interesting class of complexes appears not to have been studied further (1128). 

Aluminum is extracted from sea water into chloroform after complexation with pyrocatechol violet and the formation of an ion associate of the aluminum complex with zephiramine (tetradecyldimethylbenzylammonium chloride). With 5 ml of chloroform as much as 94.7% of the aluminum was separated from 110 ml of sea water, i.e. a 20-fold aluminum concentration could easily be achieved. Several ions, such as manganese, iron(II), iron(III), cobalt, nickel, copper, zinc, cadmium, lead, and uranyl also react with pyrocatechol violet and to some extent are extracted together with aluminum. However, the interferences of these ions and other metal ions present in sea water could be eliminated by masking with sodium diethyl-dithiocarbamate and 8-hydroxyquinaldine. In presence of these agents all the above metal ions except aluminum were extracted into chloroform51). 

NO adds reversibly to reduced cobalamin, Cbl(II).156 It does not react directly with aquacobalamin(III), (0blni(H2O)), but it does add to Cbl,n(N02 ) and Cblm(NO).175 Acid hydrolysis of the dinitroso species releases nitrite, and binding of nitrite to Cblln(H20) generates Cbln,(. 02 ). This sequence thus affords a nitrite-catalyzed mechanism for NO substitution at Cblln(H20). The reaction of NO with Com porphyrins is quite complex.176 In the first step, NO displaces an axial water ligand to form a weakly bound mono NO complex this mono NO complex reacts with a second molecule of NO to form nitrite and a reduced Co-NO complex. This latter process is called reductive nitrosylation. Manganese(II) porphyrins bind NO very rapidly.177 Stability constants have been measured for the formation of mono and bis NO complexes of Cun(dithiocarbamate)2.157... 

Rao et al. (1993) present a modification of the usual CS2 evolution method (which measures CS2 by spectrophotometry) with a method that converts maneb to a manganese-PAN complex that is extracted in isobutyl methyl ketone (MIBK) the complex then absorbs at 550 nm and can be measured from 0.37 to 3.75 micrograms/mL. Their method determines micro-quantities of maneb in commercial formulations, synthetic mixtures, grain, and in the presence of various other dithiocarbamates. The authors note that this method is particularly selective since other pesticides like ziram, zineb, and ferbam which usually interfere in other methods did not interfere under their experimental conditions. 

Manganese, zinc and iron dithiocarbamates, whether they are 1 1 or 2 1 complexes, react with copper-containing complex compounds, thus with proteins,... 

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. 

Ethylene bis dithiocarbamic acid manganese zinc complex. See Mancozeb Ethylenebis (iminodiacetic acid) tetrasodium salt. See Tetrasodium EDTA Ethylene bis (mercaptoacetate). See Glycol dimercaptoacetate... 

Separations of REEs using anion or cation exchangers, anhydrous manganese dioxide, organic complexes (ammonium pyrrohdone dithiocarbamate), precipitations with hydroxides, fluorides, and the development of combined separation schemes based on these procedures have also been reported and a short review was given by Alfassi (1994a). 

Depending on their carbon skeleton, DTCs can be categorized into three subclasses, that is,dimethyldithio-carbamates (DMDs), ethylenebis(dithiocarbamates) (EBDs), and propylenebis(dithiocarbamates) (PBDs) (Table 26.1).They are mainly produced as complexes of transition metals, preferably manganese and zinc. In the case of EBD and PBD, it is unclear if the complexes are monomer or polymer in type. Therefore, the stmcture formulae presented in Table 26.1 only provide composition. The two metal-free fungicides in use are thiram and dazomet. Dazomet is mainly used as soil sterilant (precursor of methyl isothiocyanate), whereas DTCs are typically applied to aerial parts of plants. 

Some thiolate metal complexes, unlike the oxygen complexes referred to above are powerful antioxidants (see Chapter 1) and undergo inversion to prooxidant metal ions in sunlight. The iron, manganese, cobalt, vanadium and cerium dithiocarbamates (II) are typical examples of such restrained prooxidants. 

Complexes containing bidentate sulfur-bonded ligands which form four-membered rings with the manganese atom are obtained by the reaction between [MnBr(CO) 5] and dithiobenzoic acid(2 69a) or sodium N,N-dialkyl-dithiocarbamates (2696) the products have the compositions [Mn(S2CC jH 5) (CO)4] or [Mn(S2CNR2)(CO)4] (R = CH3, C2H5) respectively. 

It is not clear when dithiocarbamates were first prepared, but certainly they have been known for at least 150 years, since as early as 1850 Debus reported the synthesis of dithiocarbamic acids (1). The first synthesis of a transition metal dithiocarbamate complex is also unclear, however, in a seminal paper in 1907, Delepine (2) reported on the synthesis of a range of aliphatic dithiocarbamates and also the salts of di-iTo-butyldithiocarbamate with transition metals including chromium, molybdenum, iron, manganese, cobalt, nickel, copper, zinc, platinum, cadmium, mercury, silver, and gold. He also noted that while dithiocarbamate salts of the alkali and alkali earth elements were water soluble, those of the transition metals and also the p-block metals and lanthanides were precipitated from water, to give salts soluble in ether and chloroform, and even in some cases, in benzene and carbon disulfide. 

The manganese ethylene bis(dithiocarbamate) complex MANEB is used as a fungicide (15). Manganese is a well-known toxin for Parkinsonism in humans, while dithiocarbamates can induce extra-pyramidal syndromes. One publication details the development of permanent Parkinsonism in a 37-year old man exposed to MANEB for only 2 years (1134), and follows a previous report of the same symptoms developed after 10 years exposure (1135). 

In further contributions, the kinetics of the reaction of [Cu(S2CNR2)2] (R = Me, Et R2 = MePh) with periodate have been studied. Oxidation is shown to be first order with respect to the complex and periodate (1729), while copper(III) complexes, [Cu(S2CNR2)2][BF4] (R =Me, Et), have been found to oxidize iron and manganese(III) tris(dithiocarbamate) complexes to give [M(S2 CNR2)3][BF4] (M = Fe, Mn) (1124). 

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