Toluene-3,4-dithiol

In the field, cassiterite ore is usually recognized by its high density (7.04 g/cm ), low solubiUty in acid and alkaline solutions, and extreme hardness. Tin in solution is detected by the white precipitate formed with mercuric chloride. Stannous tin in solution gives a red precipitate with toluene-3,4-dithiol. 

The reaction of toluene-3,4-dithiol(3,4-dimercaptotoluene) and antimony trichloride ia acetone yields a yeUow soHd Sb2(tdt)2, where tdt is the toluene-3,4-dithiolate anionic ligand (51). With the disodium salt of maleonitnledithiol ((Z)-dimercapto-2-butenedinitrile), antimony trichloride gives the complex ion [Sb(mnt)2] , where mat is the maleonitnledithiolate anionic ligand. This complex has been isolated as a yeUow, crystalline, tetraethyl ammonium salt. The stmctures of these antimony dithiolate complexes have apparendy not been unambiguously determiaed. 

Toluene-3,4-dithiol, usually called dithioP, yields a slightly soluble, dark-green complex, (CH3.C6H3.S2)3Mo(VI), with molybdenum(VI) in a mineral acid medium, which can be extracted by organic solvents. The resulting green solution is used for the colorimetric determination of molybdenum. 

Discussion. In acid solution, toluene-3,4-dithiol (dithiol) forms a red compound when warmed with tin(II) salts (compare molybdenum, Section 17.30). Tin(IV) also reacts, but more slowly than tin(II) thioglycollic acid may be employed to reduce tin(IV) to tin(II). The reagent is not stable, being easily reduced, and hence should be prepared as required. A dispersant is generally added to the solution under test. 

Reagents. Dithiol reagent solution. Dissolve 1 g toluene-3,4-dithiol in 100 mL pentyl acetate. This should be prepared immediately before use. 

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). 

Titrimetric apparatus see Graduated glassware Toluene-3,4-dithiol see Dithiol Tongs for crucibles and beakers, 98 Transmittance 648 conversion to absorbance, 709 Triangulation 245 Triethanolamine 317 Tri-n-butyl phosphate 171 Triethyl phosphate in homogeneous pptn. 425 Triethylenetetramine-fV,fV,fV, yV",fV", fV "-hexa acetic acid (TTHA) 57 Trifluoroacetylacetone 170, 237 Trimethyl phosphate in homogeneous pptn., 425... 

The Au-S bond length at 2.30 A is very similar to that in the gold(III) analogue (2.299-2.312 A) and other gold(III) complexes like Au(toluene-3,4-dithiolate) (2.31 A) suggesting substantial covalent character in the bond. 

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... 

Microgram amounts of pertechnetate can be determined by measuring the extinction of its colored complex with toluene-3,4-dithiol in 2.5 N hydrochloric acid after extraction into carbon tetrachloride . One hour must be allowed for the development of the color. The molar extinction coefficient at 450 nm is 15,000. Beer s law is followed over the range of 1.5 to 16.5 fig Tc per ml. The overall error does not exceed a standard deviation of 5%. Because many cations interfere, an initial separation of technetiiun is necessary. 

The complex formation of technetium, rhenium, and molybdenum with toluene-3,4-dithiol and its analytical application have been studied by Koyama et al. . 

Molybdenum VI) has also been determined spectrophotometrically in soil extracts using toluene-3,4-dithiol chromogenic reagent. However, copper(II) interferes in this procedure. Milham et al. [169] discussed an isoamylacetate extraction procedure for overcoming such interference. 

Modified spectrophotometric procedures are described for the quantitative determination of cobalt and molybdenum as the 2-nitrosonaphth-l-olate and toluene-3,4-dithiolate complexes in carbon tetrachloride. The extraction, chelation and phase separation steps permitted rapid sample handling, controlled interferences more effectively and provided accurate assays. The molar absorptivities for cobalt and molybdenum were 5.1 x 104 and 2.5 xl04mol/lcm, respectively, and the detection limits for both elements were 4 ng/g. 

As well as the above 2,3-dimercaptoalkanes a few other vicinal dithiols have also been sythesized. The interaction of methylmercury(II) with chelating agents such as BAL involves linear two-coordinate complexes and in only a few cases has chelation involved a bidentate ligand. In a search for evidence of thiol-containing bidentate chelation, Alcock et al.311 synthesized three sterically constrained dithiols - cyclohexane-1,2-dithiol, toluene-3,4-dithiol and bicyclo[2.2. l]heptane-2,3-dithiol - and demonstrated by spectroscopy and crystallography their formation of chelates with methylmercury(II) of the form (40). 

Natural water Sn Traces Polyether Toluene-3,4-dithiol... 

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