Silicon, Germanium, Tin, and Lead Complexes

Pentacoordinate silicon complexes can also be prepared via the reaction of diaryldichlorosilanes with carbenes 4 (R = Et, Pr R = Me). Interestingly, a 2-(trimethylsilyl)imidazolium salt (56) was formed when MesSil was treated with 4 (39). Unfortunately, no information regarding the crystal structures of these species is available. 

Pentacoordinate tin complexes can also be isolated from the reaction of diphenyldichlorostannane with 4 (R = Pr, R = Me) 38). The structure of the Ph2SnCl2 complex 60 was shown to be very similar to that of 54 by X-ray crystallography. Thus, the geometry around 

Cyclopropenylidene Complexes of Divalent Germanium, Tin, AND Lead Amides 

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C. Group 13 Trialkyls and Triaryls Silicon, Germanium, Tin, and Lead Complexes... 

Silicon, germanium, tin and lead can make use of unfilled d orbitals to expand their covalency beyond four and each of these elements is able (but only with a few ligands) to increase its covalency to six. Hence silicon in oxidation state -f-4 forms the octahedral hexafluorosilicate complex ion [SiFg] (but not [SiCl] ). Tin and lead in oxidation state -1-4 form the hexahydroxo complex ions, hexahydroxostannate(IV). [Sn(OH) ] and hexahydroxoplum-bate(IV) respectively when excess alkali is added to an aqueous solution containing hydrated tin(IV) and lead(IV) ions. 

The range of organo-silicon, germanium, tin, and lead porphyrin complexes reported to date are given in Table Some mono- and dialkyltin... 

Silicon, Germanium, Tin and Lead Table 7 Examples of Five- and Six-Coordinate Complexes and Complex Anions... 

Catenated Organic Compounds of Silicon, Germanium, Tin, and Lead Henry Gilman, William H. Atwell, and Frank K. Cartledge Cyclobutadiene-Metal Complexes P. M. Maitlis Organoarsenic Chemistry W. R. Cullen... 

Although transition metal germanium, tin and lead complexes have been known for a considerable period of time compared to the area of transition metal-silicon chemistry, studies on these systems are less developed. There are a variety of reviews, or... 

Nucleophilic carbenes have been reported to react with Eewis acidic group 14 complexes with the isolation of neutral or ionic compounds via simple adduct formation or displacement of a halide ion. > The range of carbene complexes of silicon, germanium, tin, and lead, as well as some related cyclopropenylidene complexes are described below. 

Table III lists the trifluoroacetato complexes of silicon, germanium, tin, and lead that have been characterized. Although a large number of organotin(IV) trifluoroacetates have been reported, the only complete series R Sn(02CCF3)4 (where n = 0-4) is the R = vinyl series. Peruzzo et al. (194) obtained (CH2=CH)3Sn(02CCF3) by the exchange reaction of (CH2=CH)4Sn and Na(02CCF3). The dropwise addition of (CH2=CH)4Sn to anhydrous CFgCOgH at room temperature results...

Ojima, I. Kogure, T. Reviews on Silicon, Germanium, Tin, and Lead Compounds Vol. 5, No. 1, 7-66, 1981. This reference gives a review of hydrosilation with metal complexes other than Speier s catalyst. 

Group 14 elements include carbon, silicon, germanium, tin, and lead. As already noted, carbon forms a solid of complex structure that does not exhibit metallic properties. The second and third members of the group, silicon and germanium, cannot be classified as metals either they are only semimetals. 

This method has been the most useful for the preparation of metal complexes. Several compounds containing main-group elements such as boron, gallium, indium, silicon, germanium, tin and lead as the metal are shown in equations 134 , 135, 136 , 13791.146, i3gi3i 139 , 140 and 141 . 

Halides of Silicon, Germanium, Tin, and Lead.—Interest in halide derivatives has been focussed mainly on the synthesis of metal-halogen bonds, structure and bonding, and complex formation. A new method for the... 

TM=tetrel complexes (1) W. Petz, Chem. Rea, 86, 1019 (1986). Transition Metal Complexes with Derivatives of Divalent Silicon, Germanium, Tin, and Lead as Ligands, (m) W. A. Herrmann, Angew. Chem., Int. Ed. Engl., 25, 56 (1986). Multiple Bonds Between Transition Metals and Bare Main Group Elements Links Between Inorganic Solid State Chemistry and Organometallic Chemistry. 

In contrast to the sulfide of silicon (p. 187). the sulfides of tetravalent germanium (white) and tetravalent tin (yellow) are stable in water, but form complexes in the presence of excess sulfide ion. The sulfides of divalent tin and lead (both black) dissolve neither in strong base, in excess sulfide, nor in dilute acids. Note that PbS has the same structure as sodium chloride and is probably the most nearly covalent salt known having this structure, its color and metallic lustre setting it apart from the structurally similar ionic halides and oxides. 

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