Trithiocarbonate ions

The preparation and chemistry of nickel trithiocarbonate complexes have been studied in detail, and both [NKCSs) ] and [Ni(CS4)2 have been isolated (379). Shul man and co-workers (379) reprepared the known [Ni(NH3)3(CS3)]and [Ni(en)3]CS3, and the kinetics of the reaction of Ni(II) with the trithiocarbonate ion in methanol was studied the results confirmed the previously proposed ion-pair mechanism (380). 

The reaction, evidently, starts with addition of trithiocarbonate ion across the exocyclic C = C bond followed by elimination of a CS2 molecule from intermediate 90. Intramolecular S-nucleophilic attack and subsequent departure of two bromide ions from aH-adduct 91 furnishes condensed thiopene 89 (Scheme 28). 

Complexation with zinc effectively separates the C3S5 dianion from the trithiocarbonate ion in high yield, and the material obtained is sufficiently pure for further reactions. The quaternary ammonium zincate salt is alkylated slowly but smoothly by many halides at room temperature in solvents such as acetone or tetrahydrofuran. Reaction of the zincate with benzoyl chloride followed by cleavage of the resulting benzoate by sodium ethoxide in ethanol provides the much more reactive species NajCaSs. The sodium salt is, however, very air sensitive,5 whereas the zinc salt is completely stable. 

The cleavage of the sulfur-carbon bond of thioacetals and thioketals,671 thioortho-formates672 [Eq. (3.101)], and tetraalkyl thioorthocarbonates673 [Eq. (3.102)] leads to the corresponding mono-, di-, and trithiocarbenium ions, respectively. Trimethylthio-carbenium ion 361 was also prepared by methylating dimethyl trithiocarbonate [Eq. (3.102)]. 

Formation of 5-substituted 5-mercaptothiatriazoles from trithiocarbonate 5,5-dioxides (71CC314) or alkylthio- or arylthio-thiocarbonyl p-toluenesulfonyl disulfides reacting with azide ion has been reported (79CC1135) but these methods have not found any synthetic application. 

The earliest studies showed no evidence for intermediates in the reactions of carbonoxysulphide and of carbon disulphide with hydroxide ion (for which the stable products are carbonate, trithiocarbonate and sulphide). Wronski followed the rates of formation of sulphide ion (1) and of trithiocarbonate (2), viz. 

Trithiocarbonate and dithiocarbamate decompositions in alkaline solutions have received preliminary study. The former is said to be retarded by hydroxide and sulphide ions (but also by sodium chloride) , and to involve an activation energy of 19.8 kcal.mole". ... 

Dialkyl, alkyl aryl, and diaryl trithiocarbonates are reduced in DMF to the radical anion, which loses a thiolate ion [146-148]. The rate of the cleavage was measured with CV for substituted diphenyltrithiocarbonates, the rate constant of the cleavage was found to vary linearly with Hammett s substituent constant a. The anion radicals of mono- and... 

In contrast to the facile formation of ethylene trithiocarbonate (52) by the reaction of ethylene dibromide with sodium trithiocarbonate as shown in Equation (10) and Scheme 9, the major course of the reaction of ethylene dibromide with the selenodithiocarbonate ion (53) <71ZAAC(384)235> has been reported to lead to the precipitation of red selenium (75%), accompanied by the vigorous evolution of ethylene, and the expected thiaselenoranethione (54) was obtained only in 2% yield. The reaction process can be rationalized by assuming that the initially formed monoalkylated anion (55) is in equilibrium with carbon disulfide and the /i-bromoethylselenide ion (56) the latter can rapidly cyclize to the extremely thermolabile ethylene episelenide (1). 

As another example, Lai et al. [189] reported the synthesis of carboxyl-terminated trithiocarbonates. The synthesis of S.S -bislaa -dimethylacetic acid)trithiocarbonate is presented in Scheme 31 and requires the use of carbon disulfide, which reacts with hydroxide ions. This synthesis yields trithiocarbonate with purities above 99%. 

The reaction of CS2 with OH to form the hydrogen dithiocarbonate ion HCS2O" is rate determining for the reaction, preceding the rapid subsequent reaction with cellulose. The decomposition of the dithiocarbonate ion forms HS (as a by-product of sulfite) and COS (reacts to form trithiocarbonate) ... 

Trigonal-planar symmetry 299 Trimethylene oxides 102 Trithiocarbonates 19,31,214 Tropolones 95, 123 Tropones 123 Tungstate ion 285, 292 Twisting vibrations 2... 

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