Peter R. Wells

Acetolysis of hexaaryldileads

The acetolyses of hexaaryldileads (XC6H4)6Pb2 in which X is H, p-CH3O, m- and p-CH3, m- and p-Cl and 2,5-(CH3)2, have been examined kinetically at 40° in 1 3 acetic acid/dioxane solution. Hexaphenyldilead has been examined also at several temperatures, in two other acetic acid/dioxane solutions and in the presence of various added salts and tetraphenyllead. The results are not consistent with a prior dissociation to tetraaryllead and diaryllead, but correspond to electrophilic CPb cleavage to yield a partially acetoxylated derivative which decomposes to the observed products triaryllead acetate, diaryllead diacetate, lead(II) acetate and aromatic hydrocarbon. Partially acetoxylated derivatives, Ar3Pb2(OCOCH3)3 where Ar is phenyl and p-tolyl, have been prepared in acetic anhydride/acetic acid solution and on the basis of mass spectra are suggested to possess the unsymmetrical (CH3COO)Ar2PbPbAr(OCOCH3)2 structures. Employing 14C labelled materials it has been found that no detectable exchange takes place between hexaphenyldilead and tetraphenyllead in benzene or tetrahydrofuran solution at 40°, nor between hexaphenyldilead and triphenyllead chloride in benzene solution at 40°.

Reactions of hexamethylditin with alkylmercury salts I. Stoichiometry and rate step

Hexamethylditin in methanol solution reacts rapidly with mercuric chloride to yield mercury and trimethyltin chloride. With alkylmercuric salts the reaction is complex, yielding tetraalkyltin and/or dialkylmercury, depending upon the reactivity of the alkylmercuric salt. An electrophilic substitution mechanism involving trimethylstannyl mercurials as transient intermediates is suggested. The reaction of hexaalkylditin with diarylmercury is suggested to follow a homolyric pathway.

Some reactions of tris(trimethylstannyl)- and tetrakis(trimethylstannyl)-methane

Abstract With a variety of electrophilic reagents reaction occurs exclusively at the CH 3 Sn bonds of [(CH 3 ) 3 Sn] 4 C and [(CH 3 ) 3 Sn] 3 CH. While the inner SnC bonds remain intact, methyl groups may be progressively cleaved off, one from each of the trimethylstannyl groups; in the case of bromine a second Me group may be cleaved from each of the SnMe 2 Br groups. The various products were identified by 1 H, 13 C and 119 Sn NMR spectroscopy.

Reaction of hexamethylditin with dimethyltin dichloride. I. Product composition and intermediates

Hexamethylditin in methanol solution reacts with dimethyltin dichloride to yield as major products trimethyltin chloride and polymeric materials whose composition depends upon the molar ratio of the reactants. Tetramethylditin dichloride is a significant minor product together with small amounts of various intermediates which have been tentatively identified. The stoichiometry of the reaction has been established.

Hexamethyldilead. I. Preparation, thermal decomposition and methanolysis

The preparation, stability and storage of pure samples of hexamethyldilead is discussed. Thermal decomposition in hydrocarbon and carbon tetrachloride.

Hexamethyldilead : II. Reactions with trimethyllead and trimethyltin chlorides☆

Abstract Hexamethyldilead reacts with trimethyltin chloride or trimethyllead chloride to yield tetramethyltin and/or tetramethyllead and lead(II) chloride three

Reactions of hexamethylditin with alkylmercuric salts II. Reactions of trimethylstannylmercury intermediates

Abstract The kinetics of the formation of two kinds of products from the intermediate (CH3)3SnHgCH3, postulated to be formed by reaction of hexamethylditin with methylmercuric salts, have been studied. The two processes are suggested to be electrophilic attack at mercury by methylmercuric halide, and at mercury bound carbon by trimethyltin halide. When pure, the intermediate may be more stable than has been previously supposed.

Isomerization in Olefin Formation in Radiation Degradation of Poly(Olefin Sulphone)s

SummaryGamma irradiation of poly(3-methyl-1-butene sulphone) in the solid state at 20°C produced a mixture of isomers,viz. 3-methyl-1-butene (61%), 2-methyl-1-butene (2%) and 2-methyl-2-butene (37%). Similarly, poly(1-butene sulphone) yielded 1-butene (65%) and 2-butene (35%). A hydride shift reaction in a polymer cation produced by main-chain scission is proposed to account for the isomerization.

Hexamethyldilead: III. Reaction with metal salts and organomercurials☆

Abstract Hexamethyldilead reacts with various metal salts very rapidly in comparison with the rate of mixing of the reactants so that the product composition depends upon the order of addition and the competition between rapid reactions rather than any fundamental differences in mechanism.

Cleavage of hexaphenyldilead by mercuric salts

The reactions of hexaphenyldilead with mercuric chloride and with mercuric acetate in 15/1 v/v dioxane-methanol at 30° have been examined. Kinetic and product composition data have been shown consistent with an initial electrophilic CPb bond cleavage yielding a pentaphenyldilead followed by two competing reactions. One involves further CPb bond cleavage followed by decomposition, while the other involves PbPb bond cleavage yielding an unstable (triphenylplumbyl)mercury intermediate.