Carbon disulphide complexes

Dimethyl 2-methylenepentanedioate. Methyl acrylate (30.0 g, 349 mmol) (distilled immediately before use) and dry pyridine (30 ml, CAUTION) containing tris(cyclohexyl)phosphine-carbon disulphide complex (2.0 g, 6 mmol) (1) are refluxed under nitrogen for 16 hours. The deep red solution is cooled and the pyridine removed under reduced pressure. The residue is taken up in ether (400 ml) and the solution washed with aqueous 1 m hydrochloric acid (3 x 40 ml). The combined aqueous layers are extracted with ether (2 x 50 ml) and the combined organic layers washed with 1 m hydrochloric acid (30 ml), saturated brine (40 ml) and saturated aqueous sodium hydrogen carbonate (2 x 30 ml), dried over sodium sulphate and evaporated. Distillation of the oil gives dimethyl 2-methylenepentanedioate (23.8 g, 79%) as a liquid, b.p. 66-68 °C/1 mmHg i.r. (thin film) 1738, 1715, 1635cm-1. 

Notes. (1) Pyridine was stored over potassium hydroxide and distilled immediately before use. The tris(cyclohexyl)phosphine-carbon disulphide complex is prepared by the method of K. Issleib and A. Brack.9 This involves the addition of carbon disulphide to an ethereal solution of tricyclohexylphosphine, the precipitate is washed with light petroleum (b.p. 50-60 °C), and recrystallised under a nitrogen atmosphere from either methanol, ethanol or dioxane the complex has m.p. 118 °C. 

To the cold acid chloride add 175 ml. of pure carbon disulphide, cool in ice, add 30 g, of powdered anhydrous aluminium chloride in one lot, and immediately attach a reflux condenser. When the evolution of hydrogen chloride ceases (about 5 minutes), slowly warm the mixture to the boiling point on a water bath. Reflux for 10 minutes with frequent shaking the reaction is then complete. Cool the reaction mixture to 0°, and decompose the aluminium complex by the cautious addition, with shaking, of 100 g. of crushed ice. Then add 25 ml. of concentrated hydrochloric acid, transfer to a 2 htre round-bottomed flask and steam distil, preferably in the apparatus, depicted in Fig. II, 41, 3 since the a-tetralone is only moderately volatile in steam. The carbon disulphide passes over first, then there is a definite break in the distillation, after whieh the a-tetralone distils completely in about 2 htres of distillate. 

The reaction of a-aminonitriles and carbon disulphide was stated by Cook and Heilbron to give 5-amino-2-mercaptothiazoles however, they later found that the same reaction with aminoacetonitrile was more complex. When aminoacetonitrile sulphate in ethanolic solution was treated with carbon disulphide, the dithiodicarbamate 9 was formed. Benzylation was then carried out treatment of the resulting ester 10 with phosphorus tribromide with subsequent loss of water gave 5-amino-2-benzylthiothiazole 11 in a quantitative fashion. The rapid reaction was thought to be the first example of the formation of a 5-aminothiazole from an a-aminoamide. 

With phosphorus trichloride, a rather complex reaction results partly in the formation of [PhaP N uPPha PPhCl]+ Cl. The reactivity of the phosphorus(iii) atom is also demonstrated by its ability to desulphurize thiophosphoryl chloride, and its ready reactions with Group VI elements, diborane, and carbon disulphide ... 

Carbon disulphide was used as an extraction solvent when analysing epoxy resins. On one occasion, adding to a hardener produced a vigorous fume-ofif leaving a residue looking like sulfur [1], Amines and complexes thereof are used as hardeners, and the reaction with, especially, polyamines to give dithiocarbamates is surprisingly exothermic [2],... 

The more powerful the solvent-solute interaction, the more pronounced will solvent broadening be for this reason, saturated hydrocarbons are preferred as solvents for spectroscopy, and such strongly interacting media as methylene chloride and chloroform are to be avoided. It is obvious that the requirements of spectroscopy and those of solubility are in direct conflict. Carbon tetrachloride and carbon disulphide are often used as compromise solvents ) (although both of these react thermally or photochemically with many carbonyl complexes) but are generally inferior spectroscopically to alkanes. 

In support of the theory that in brown soln. a complex of solute and solvent is formed, F. Dolezalek 1 having shown that the partial press, of each form of a substance in a soln. is proportional to the molecular proportion of it present in the mixture, P. Wantig found that boiling soln. of iodine in ether, carbon disulphide, carbon tetrachloride, chloroform, and benzene agree with the assumption that even at the b.p. there is a considerable amount of association between iodine and the solvents which form brown soln. With this hypothesis also before them, J. H. Hildebrand and B. L. Glascock measured the depression of the f.p. of certain neutral solvents—bromoform and ethylene dibromide—produce by iodine and certain liquids separately and together. With mixtures which produce violet soln. the total depression of the mixture in the constituents are considered separately or together with mixtures which produce brown soln. the total depression with the mixture is less than the sum of the separate depressions. This is taken as a proof... 

Arsenic exhibits allotropy, which is characteristic of non-metals the usual, more stable, metallic form resembles the typical metals in appearance and in being a fairly good conductor of electricity. Under atmospheric pressure it begins to volatilise at about 450° C. and passes into a vapour containing complex molecules, As4, which at higher temperatures dissociate to As2 this complexity is not unusual in non-metals. The yellow allotrope, which is stable at low temperatures, resembles white phosphorus in being soluble in carbon disulphide—a property which emphasises the non-metallic character of this variety. The reactivity of the allotropes, as in the case of phosphorus, differs considerably. 

Two classes of material will be described here - the metal dithiolenes and rare earth metallocenes. In the metal dithiolenes a strong, low energy pi-pi transistion occurs in the near IR (9.10). This can be tuned from about 700 nm to 1400 nm by altering the metal ion, substituents or charge state of the dithiolene. The dithiolenes are particularly attractive because of their optical stability which has been exploited in their use as laser Q-switch materials. In the rare earth complexes the near IR band is provided by/-/transistions of the rare earth ion rather than the cyclopentadienyl ring structure various nonlinear optical phenomena have been observed in glasses incorporating similar ions. Previous studies have shown that dicyclopentadienyl complexes such as ferrocene have off-resonant nonlinearities similar to nitrobenzene or carbon disulphide (11-13)... 

In order to clarify the mechanism, the reaction of carbon disulphide with mercury bis(n-butanethiolate) was studied. On the basis of results obtained, it was suggested that this reaction involved the formation of a coordination complex, followed by the formation of active species containing the Hg-SC(S) bond. Moreover, the cyclic trithiocarbonate, ethylene trithiocarbonate, found to be present in trace amounts in copolymerisation products, was excluded as a possible intermediate for the copolymer formation, since it did not undergo any polymerisation under the given conditions [249],... 

Judging from the decreasing metallic properties in the series, Pb, Sn, Si, C, we should expect the tetrachlorides to hydrolyze more readily as we progress in this order. Two factors modify this effect the tendency to form a complex acid such as H SnCle with the anion SnCle--, and the insolubility or total lack of ionization of the tetrachloride. Explain from this point of view why carbon tetrachloride and carbon disulphide are without perceptible action with water. 

An obvious extension of the above studies concemig the reactivity of olefine complexes towards C02 is the investigation of the chemistry of the relate molecule CS2. Carbon disulphide chemistry is often... 

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