Zinc dithiol

Zinc dithiol is more stable than toluene-3,4-dithiol. It can be used to prepare a solution of toluene-3,4-dithiol and for many purposes it is added as the solid or as a suspension in ethanol (see Ref. 2). 

It has been suggested that the use of zinc dithiolate complexes as vulcanization catalysts may be closely related to the ability of these complexes to form sulfur-rich complexes that have very labile disulfide sulfur atoms (230). 

The amplification method for arsenic is based on its extractive separation as molybdoarsenic acid and determination of Mo with Sulphonitrophenol S (e = 4.5 10 ) or zinc dithiol [56]. The molybdoarsenic acid, after extraction into a mixture of butyl acetate and ethanol, is decomposed, then Mo(VI) is reduced to Mo(Ul) in a Jones reducer, and finally Mo is oxidised to Mo(Vl) be means of Fe(Itl). The Fe(ll) produced in this reaction gives a coloured complex with ferrozine. The amplification factor is 36, and e=9.4 10 [57]. 

Stanton, R. E., and Hardwick, A. J. (1967). The colorimetric determination of molybdenum in soils and sediments by zinc dithiol. Analyst 92 387-90. 

Magnesium triflate and zinc triflate are outstanding catalysts for the intro duction of the thioketal group for the protection of the ketone function [126] The reaction of a variety of ketones with ethane 1,2-dithiol in the presence of these triflates proceeds under mild conditions to form the corresponding thioketals in high yield (equation 62)... 

A trimeric species was formed with one equivalent of a bis(benzimidazole) ligand in the presence of benzylthiolates (59) (Figure 10). Zinc-zinc distances were in the range 3.069-3.958(2) A.126 Other zinc-thiolate trinuclear compounds include Zn3(CH2SiMe3)3(SC6H2iPr3)3 and Zn3(o-phen)2(toluene-3,4-dithiolate)3 but have little structural similarity.81,525... 

Dithiolate ligands are of interest in biological and materials chemistry, and zinc polysulfido complexes can effect the dehydrogenative conversion of alkenes into dithiolates (Scheme 2). 

Naphthalenedithiol can be prepared by adding 1,5-naph-thalenedisulfonyl chloride to an ethanol solution of tin (II) chloride 2-hydrate saturated with hydrogen chloride.6 An 80% yield of the crude dithiol melting at 103° was previously reported using zinc dust and sulfuric acid.7... 

Synthesis. These macrocycles are prepared from seven-membered ring dinitrile complexes, 84a-84c (Scheme 17), which contain either methylene, sulfur or oxygen in the five position (129). These cyclic dinitriles are synthesized by alkylating maleonitrile dithiolate or derivatives thereof with the corresponding dihalide. The dinitriles 84a-84c can be cyclized in magnesium propoxide to form porphyrazines 85a (33%), 85b (19%), and 85c (27%) (Scheme 17), which can be demetalated with trifluoroacetic to form 86a-86c. Additionally, 86a has been remetalated with nickel (87a, 92%), copper (88a, 95%), and zinc (89a, 94%). The sulfur and oxygen derivatives 85b, 85c, 86b, and 86c are of low solubility and are not suitable for further manipulation. 

Probucol, a hypocholesterolemic drug that possesses antioxidant activity, inhibits the ex vivo release of IL-1 from LPS-stimulated macrophages of mice pretreated orally with 100 mg/kg/day of this compound [94,95]. This compound has been shown to inhibit LPS-induced zinc-lowering effect, is cited as direct evidence for the inhibition of IL-1 release, and may be useful candidate for the treatment of atherosclerosis [95,96]. An amino-dithiol-one derivative (RP 54745) blocked the proliferative action of IL-1 P on murine thymocytes in vitro and also inhibited the production of IL-1 in mouse peritoneal macrophages in vitro and in vivo. The compound RP 54745 selectively inhibited the expression of IL-la and IL-1 3 mRNA while TNFa mRNA was unaffected [97, 98]. 

The great drawback to this reagent is its proneness to oxidation and it is often stored as the zinc complex from which it is released by dissolving in acid or alkali. The analogous quinoxaline-2,3-dithiol has been recommended for the determination of Ni and Co, and 2-mer-captobenzothiazole (28) for cadmium through extraction of its complex into chloroform.52... 

N-(2,3-Dimercaptopropyl)phthalamidic acid (41, DMPA) has been shown to form relatively stable complexes with cadmium, zinc and mercury312. DMPA has also been shown to enhance faecal and urinary excretion of mercury in mice and arsenic in mice and rabbits. For the decorporation of arsenic, taken in as arsine, the administration of 3-(tolylthio)propane-l, 2-dithiol (42) has been proposed in the USSR313. ... 

Electrochemical reduction of the salts (4) provides radicals (18) which dimerize or undergo further reduction to anions (32) or dianions (80MI43100). The reduction potentials are not much affected by substituents. Reduction with zinc in aprotic conditions gives bi(l,2-dithiol-3-yls) (59), and 3-chloro-l,2-dithiolylium salts (35a X = Cl) are converted into bi(l,2-dithiol-3-ylidenes) (20) (75TL3473). Divalent chromium converts the 3,5-dimethyl-l,2-dithiolylium cation into a dithioacetylacetonate ligand (72AJC2547). The reaction of 3,5-diamino-l,2-dithiolylium salts (8) or alkyl derivatives with thiols provides dithiomalonamides (60) by electron transfer (63ACS163). 

Macrocycle LXXXVIII was prepared (13) in an 8% yield from the reaction of the disodium salt of ethane-1,2-dithiol with di(2-bromo-ethyl)amine in ethanol at high dilution, and it was found to complex with Ni(II) and Co(II) ions when these were added as salts. A macrocycle containing the same donor atoms (LXXXIX) has been obtained in the form of complexes (87) by the template reactions of l,2-bis(2-aminophenylthio)ethane and 1,4-bis (2-formylphenyl)-1,4-dithiabutane with Ni(II) and Co(II) perchlorates. Iron, cobalt, nickel, and zinc as their M(II) perchlorates have been used as templates in the formation of XC (55, 133). 

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