Dibismuthines reactions

Dibismuthines. Only about a do2en tetraalkyl- and tetraaryldibismuthines are known (135). These compounds can be obtained by the reaction of a sodium dialkyl- or diarylbismuthide and a 1,2-dihaloethane (66—69) ... 

Tetraethyldibismuthine [81956-27-6], CgH2QBi2, undergoes a similar reaction at 40°C (67). At 0°C this dibismuthine as well as tetra-4-tolyldibismuthine [114245-28-2], C2gH2gBi2, (105) decompose to form dark polymeric soHds ... 

The so-prepared compounds are stable in the pure form, whereas they easily undergo consecutive reactions in solution under cleavage of the E—E bond (see Sect. 3.1). Four tetraalkyldistibine (32-35) and two -dibismuthine bisadducts (36 and 37) have been structurally characterized (Table 8). 

Reactions of tetraalkyldistibines and -dibismuthines with trialkylalanes and -gallanes yield bisadducts of the type [R3M]2[E2R4]. These compounds are stable in the solid state, while they easily undergo consecutive reactions in solution. Completely alkyl-substituted heterocycles [R2MER x are formed under cleavage of the Sb—Sb bond, as was demonstrated for two Ga—Sb heterocycles. 

An alternative preparative route to R2QER acid esters (Q = P, As, Sb, Bi E = S, Se, Te) of interest due to its generally applicability to all the heavier group 15 and 16 elements, is the dismutation reaction between diorganodichalco-genides and tetraorgano-diphosphines, -diarsines, -distibines or -dibismuthines (Equation 17).2... 

In sharp contrast to the intensely studied reactions of dipenteles with transition metal compounds, reactions with group 13 metal compounds are almost unknown. Only two diphosphine-borane bisadducts of Type C ([H3B]2[Me4P2], [H2(Br)B]2[Me4P2]) have been synthesized and structurally characterized65 but no diarsine, distibine or dibismuthine adducts. We, therefore, became interested in the synthesis of such compounds, focusing... 

Dibismuthines, preparation, 3, 908 Diboracyclohexadienes, reactions, 3, 39 Diboranaphthalenes, preparation, 3, 39 Diboration... 

Diphenyl disulfide (0.14 g, 0.64 mmol) was added with vigorous stirring to a solution of tetrakis(4-methylphenyl)dibismuthine (0.50 g, 0.64 mmol) in dichloromethane (15 ml) at 0°C under an argon atmosphere. The reaction mixture turned pale yellow within several minutes. After 15 min the reaction mixture was concentrated to a half volume in vacuo, diluted with pentane (3 ml), and poured onto crushed dry ice. After decantation, the yellow residue was washed with pentane and dried in vacuo to obtain the product (0.57 g, 89%) [87ZN(B)695]. 

Thus, the thermal decomposition of tetramethyldibismuthine in the presence of bromotrichloromethane may take place via the following chain mechanism, (i) Tetramethyldibismuthine decomposes first into two dimethyl-bismuth radicals, (ii) These radicals react with bromotrichloromethane to form bromodimethylbismuthine bromide and a trichloromethyl radical, (iii) The trichloromethyl radical reacts with the dibismuthine to form dimethyl(trichlor-omethyl)bismuthine and dimethylbismuth radical. The termination step is the self-combination of the trichloromethyl radicals. In fact, the major product of the reaction is bromodimethylbismuthine bromide and the second product is dimethyl(trichloromethyl)bismuthine. Trimethylbismuthine, hexachloro-ethane and tetrachloroethylene are also formed in smaller quantities [830M1859]. 

Complexes with Sb-Sb and Bi-Bi Bonds 521 Table 15.1 Examples of reactions affording distibines and dibismuthines. 

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