Silicon-tin bond

Element-element bonds, addition to G-G multiple bonds arsenic—selenium bonds, 10, 782 boron—boron bonds, 10, 727 boron—sulfur bonds, 10, 778 B-S and B-Ge bonds, 10, 758 chalcogen—chalcogen additions, 10, 752 germanium—germanium bonds, 10, 747 germanium-tin bonds, 10, 780 overview, 10, 725-787 phosphorus—phosphorus bonds, 10, 751 phosphorus—selenium bonds, 10, 782 phosphorus-sulfur bonds, 10, 781 Se-Si and Se-Ge bonds, 10, 779 silicon-germanium bonds, 10, 770 silicon-phosphorus bonds, 10, 780 silicon-silicon bonds, 10, 734 silicon-sulfur bonds, 10, 779 silicon-tin bonds, 10, 770 tin-boron bonds, 10, 767 tin-tin bonds, 10, 748... 

Keywords tin-substituted oligosilane, cyclic silane, silicon-tin bond... 

The chemistry of mono- and polycyclic oligosilanes has been well investigated, but only little is known about cyclic silanes containing the higher elements of group 14. In recent years our studies have been focused on tin-modified oligosilanes, compounds which contain at least one silicon-tin bond [1-5]. 

Additions Forming Bonds between Carbon and Silicon, Tin, and Pbospborus... 

Direct metallation of o-halogenophenoxyelement derivatives of silicon, tin, and phosphorus leads to an unstable metallated intermediate which undergoes a rapid 1,3-rearrangement under element-carbon bond formation. This type of reaction seems to be a general method for the synthesis of hydroxyphenyl element derivatives [1-4], We have studied the influence of different organoelement groups on the reaction pathway. The yield increases in the sequence R3Sn < R2P < RjSi P(0)(0R)2. 

Palladium-catalyzed addition of a silicon-tin linkage across a carbon-carbon triple bond was first reported in 1985 by the Mitchell group and the Ghenard group independently.251,252 Since then, the silastannation reaction of alkynes has been studied extensively (Table J) 25S 261... 

The tetrametalmethane species la,b which contains carbon bonded to germanium, silicon, tin, and boron have been obtained (Equations (5) and (6)),7 and the overall yield of la,b varies with the order of attachment of the different metals. 

Carbon-carbon bond formation has also been achieved using electroauxiliaries. The method developed by Yoshida and coworkers uses an auxiliary (silicon, tin, sulfur), which when added to a molecule, decreases the oxidation potential of the starting compound. Thus the chance of overoxidation can be avoided. The anodic oxidation of compounds having a... 

Although substitutions at germanium and tin bonded to transition metals are well known, only a few reports describe substitutions at silicon - . 

Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between silicon carbide and a variety of compounds at relatively high temperatures. Sodium silicate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal silicide. Silicon carbide decomposes in fused alkalies such as potassium chromate or sodium chromate and in fused borax or cryolite, and reacts with carbon dioxide, hydrogen, air, and steam. Silicon carbide, resistant to chlorine below 700°C, reacts to form carbon and silicon tetrachloride at high temperature. SiC dissociates in molten iron and the silicon reacts with oxides present in the melt, a reaction of use in the metallurgy of iron and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new silicon nitride-bonded type exhibits improved resistance to cryolite. 

Vinylsilanes react with boron trichloride to give the corresponding borodesilylation products in good yield which, in turn, can be transformed into boronic esters 124 by alcoholysis (equation 102). The initial dichloroorganoborane products can be used directly in the Suzuki-Miyaura cross-coupling reaction192. Replacement of a carbon-silicon bond by a carbon-tin bond in fluorinated alkenes (e.g. 125) can be achieved by the reaction of silanes with Bu3SnCl and KF in DMF under mild conditions (equation 103)193. It is... 

Eaborn and co-workers28 have reported product isotope ratios for the cleavage of benzyl-silicon, benzyl-tin, and aryl-tin bonds using an equimolar mixture of MeOH and MeOD as the solvent. A free carbanion would not be expected to discriminate between MeOH and MeOD in the fast step (24), and hence28 the product isotope ratio kH/kD should be unity. The values of kJkD in Table 11 indicate that the carbanions are not entirely free, but that some degree of electrophilic attack by the solvent at the benzyl carbon atom takes place, as in (V). 

Cobalt-silicon bonds, in hydridocobalt complexes, 7, 5 Cobalt—tin bonds, in hydridocobalt complexes, 7, 5 Co-catalyst effects, in olefin polymerization, 4, 1111 (—)-Goccinine, via Alder-ene reactions, 10, 593 Co-condensation sites, in metal vapor synthesis technique,... 

Homonuclear carbonyl dimers, palladium complexes, 8, 206 Homonuclear element-element bonds, addition to C-C multiple bonds boron-boron bonds, 10, 727 chalcogen-chalcogen additions, 10, 752 germanium-germanium bonds, 10, 747 phosphorus-phosphorus bonds, 10, 751 silicon—silicon bonds, 10, 734 tin—tin bonds, 10, 748... 

In contrast, use of metalloid elements, such as silicon, tin antimony or boron, which can form weak covalent bonds with oxygen, nitrogen or sulfur substituents during the course of the reaction, results in templated products that may be obtained metal-free by simple hydrolysis. These covalent template reactions (the M—X bond is essentially covalent in these cases) also have the advantage that the... 

As noted above, the lability of the Sn-C bond is often a factor determining the outcome of such reactions and this is well illustrated in a very early reaction between Na2[Fe(CO)4] with MeSnCl3, where redistribution of methyl groups took place to form 77 and 78226. An unusual hypercoordinated tin compound 79 was obtained by reacting K[Fe(CO)3 Si(OMe)3 Ph2P(2-pyridyl ] with Cl2SnPh2, which involved an unusual silicon-tin exchange227. 

The synthesis of numerous organometallic compounds containing covalent metal-metal bonds has been achieved in a variety of ways. The majority of such compounds contain silicon, germanium, or tin bonded to a transition metal the latter frequently contains carbon monoxide among its ligands. The six principal methods of synthesis, with an example of each, are as follows ... 

During the above study, it became apparent that stannyl amides exhibit lower oxidation potential compared with the original nonstan-nylated amides. These phenomena have also been reported by Yoshida et al. in their measurements of oxidation potentials of a-stannyl derivatives (Table 7). Yoshida and co-workers explained that the decrease in the oxidation potential is attributed to the rise of the HOMO level of the stannyl (or silyl) compound by interaction of the carbon-tin (or carbon-silicon) a bond and the nonbonding p orbital of the oxygen atom. 

In organic syntheses allylsilanes and allylstannanes have been used extensively as allyl anion equivalents during the last two decades [187-190]. The regioselective attack of electrophiles, which finally yields products with allylic inversion (Scheme 43), has been explained by the hyperconju-gative stabilization of carbenium centers by the carbon-silicon or carbon-tin bond in the j3-position [191-196], which has initially been derived from solvolytic experiments [197-199]. 

---