Oxidation of bis(triethylgermyl)mercury in the presence of tert-butyl alcohol

The oxidation of bis(triethylgermyl)mercury by oxygen in the presence of tert-butyl alcohol has been investigated. It has been shown that the dependence of the rate of oxidation on the value of n ¹ for tert-butyl alcohol within the range n = 0–12 is similar to that for unassociated ligand-catalysts. On increasing n further (from 12 to 60) increasing association of the alcohol causes a drastic increase in the reaction rate relative to the increase in n due to the higher catalytic activity of the high molecular weight associated species.     

Interaction of dicyclopentadienyltitanium dichloride with bis(triethylgermyl)-cadmium and -mercury

The reaction of dicyclopentadienyltitanium dichloride with bis(triethylgermyl)mercury in benzene solution at 20° yields metallic mercury quantitatively, titanocene monochloride and triethylchlorogermane. The reaction of dicyclopentadienyltitanium dichloride with bis(triethylgermyl)cadmium leads to the formation of a complex of the following general composition: [Cp₂TiCl₂ - Cd(GeEt₃)₂]. The reactivity of this complex has been studied: in toluene solution at 20° it decomposes slowly to yield metallic cadmium, triethylchlorogermane and Cp₂TiCl(GeEt₃).     

The reaction of ethylene sulfide with isothiocyanates

Ethylene sulfide reacts with isothlocyanates in the presence of triethylamine catalyst at 20°C, to give low-molecular copolymerization products having the general formula [-C(NR)-S-CH₂-CH₂-S-]n. Their hydrolysis gives a salt of the amine and [-C(O)-S-CH₂CH₂S-]_n. Vacuum-heating the latter gives ethylenedithiocarbonate, and hydrogen peroxide oxidation in formic acid gives ethane disulfonic acid. Treatment of the copolymer from phenyl isothiocyanate and ethylene sulfide with liquid ammonia, amines, or aqueous alkali results in splitting and formation of 2-phenylimino-1,3-dithiolane, while its reaction with ethylene oxide in the presence of triethylamine gives 3-phenyloxazolid-2-one.     

Reactions of compounds containing SnLi and GeLi bonds with organic and organometallic peroxides

The reactions of tris(trimethylsilylmethyl)stannyllithium, tris(trimethylsilylmethyl)germyllithium and triethylgermyllithium with di-t-butyl peroxide, bis(trimethylsilyl)peroxide, trimethyl(t-butylperoxy)silane, triphenyl(t-butyl-peroxy)germane, bis(triphenylgermyl) peroxide, triphenyl(trimethylsilylperoxy)-germane, benzoyl peroxide and dicyclohexyl peroxydicarbonate were investigated. The reactions proceed under mild conditions with nucleophilic attack by the R₃M anion (R = Et, Me₃SiCH₂, M = Ge, Sn) on one of the peroxide oxygen atoms. In the case of unsymmetrical organometallic peroxides the character of nucleophilic cleavage is dependent on the nature of the starting nucleophile, steric effects of peroxide group substituents and other factors.     

Non-innocent behaviour of imido ligands in the reactions of silanes with half-sandwich imido complexes of Nb and V: a silane/imido coupling route to compounds with nonclassical Si--H interactions

Reactions of imido complexes [M(Cp)(=NR')(PR'3)2] (M=V, Nb) with silanes afford a plethora of products, depending on the nature of the metal, substitution at silicon and nitrogen and the steric properties of the phosphine. The main products are [M(Cp)(=NR')(PR3)(H)(SiRnCl3-n)] (M=V, Nb; R'=2,6-diisopropylphenyl (Ar), 2,6-dimethylphenyl (Ar')), [Nb(Cp)(=NR')(PR'3)(H)(SiPhR2)] (R2=MeH, H2), [Nb(Cp)(==NR')(PR'3)(Cl)(SiHRnCl2-n)] and [Nb(Cp)(eta 3-N(R)SiR2--H...)(PR'3)(Cl)]. Complexes with the smaller Ar' substituent at nitrogen react faster, as do more acidic silanes. Bulkier groups at silicon and phosphorus slow down the reaction substantially. Kinetic NMR experiments supported by DFT calculations reveal an associative mechanism going via an intermediate N-silane adduct [Nb(Cp){=N(-->SiHClR2)R'}(PR'3)2] bearing a penta-coordinate silicon centre, which then rearranges into the final products through a Si--H or Si--Cl bond activation process. DFT calculations show that this imido-silane adduct is additionally stabilized by a Si--HM agostic interaction. Si--H activation is kinetically preferred even when Si--Cl activation affords thermodynamically more stable products. The niobium complexes [NbCp(=NAr)(PMe3)(H)(SiR2Cl)] (R=Ph, Cl) are classical according to X-ray studies, but DFT calculations suggest the presence of interligand hypervalent interactions (IHI) in the model complex [Nb(Cp) (==NMe)(PMe3)(H)(SiMe2Cl)]. The extent of Si--H activation in the beta-Si--HM agostic complexes [Cp{eta 3-N(R')SiR2--H}M(PR'3)(Cl)] (R'=PMe3, PMe2Ph) primarily depends on the identity of the ligand trans to the Si--H bond. A trans phosphine leads to a stronger Si--H bond, manifested by a larger J(Si--H) coupling constant. The Si--H activation diminishes slightly when a less basic phosphine is employed, consistent with decreased back-donation from the metal.     

Reactions of organogermanium derivatives of mercury with bromine

Conclusions The bromination of bis(triisopropylgermyl)mercury by bromine gives a high yield of triisopropylgermylmercury bromide. It was found that triisopropylgermylmercury bromide and other compounds of this type reduce HgX₂ to Hg₂X₂ (X=halide).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 927–929, April, 1986.