Germanium, Tin, and Lead Complexes

The anionic orthometallated compound [Fe(CO)2 P(OPh)3 (PhO)2POC6H4 ] reacts with organotin and -lead halides to form Fe-Sn and Fe-Pb bonds (Equation (47)).  

A new silyl-substituted heterocubane of tin and nitrogen was synthesized, and reaction with FcaCCOlg led to the addition of Fe(CO)4 fragments to two of the tin atoms (Equation (48)).  

Mononuclear Iron Carbonyls without Hydrooarbon Ligands 

Iron carbonyl complexes containing tin(ll) ligands could also be obtained starting from arene iron complexes by displacement of the arene (Equations (49) and (50))4 Reactions of (arene)Fe(SnR2)(ethene) or bis bis(2- /t-butyl-4,5,6-trimethylphenyl) Sn Fe( -toluene) with carbon monoxide led to the substitution of the ethene and toluene ligands (Equation (49))4 The complex bis bis(2- /ir-butyl-4,5,6-trimethylphenyl) Sn Fe( j -toluene) was synthesized and reacted with 1 atm of carbon monoxide (Equation (50)). Attempts to synthesize the product in which only the toluene is substituted were unsuccessful. 

The cyclic FcaSna complex reacts with PdCl2(SEt2)2 to substitute one of the Sn atoms by Pd (Equation (51)). 

---

In the report that described the synthesis of 108 (777), Whitmire also observed that the reaction between NaBi03 and methanolic [Fe(CO)s] in the presence of hydroxide afforded the trianionic species [Bi Fe(CO)4 4]3, 110, which was subsequently characterized by X-ray crystallography (775). Cluster 110 contains a central bismuth atom tetrahedrally coordinated by four Fe(CO)4 fragments and is isoelectronic with the anionic tetracobalt-indium complex, 27, and the neutral tetracobalt-germanium, - tin, and -lead complexes, 68, 71, and 72. Oxidation of 110 affords 108 (777), while acidification (772) yields the hydride-containing cluster [BiFe3(CO)9(/i-H)3], 111, which also contains a tetrahedral BiFe3 core. Johnson and Lewis (114) have... 

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... 

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. 

Acidity, complexing, basicity and H-bonding of organic germanium, tin and lead compounds experimental and computational results ... 

The aim of this review is to focus on the hydrogen bonding, the acidity and basicity, complexing as well as some aspects of computational chemistry concerning the organo-element chemistry of germanium, tin and lead. This chapter is not exhaustive in scope, but rather consists of surveys of the most recent decade of work in this still developing area. This chapter emphasizes the synthesis, reactions and molecular structures of the class of... 

There are some examples of macrocyclic complexes of germanium, tin and lead reported in the recent literature. Several crown ethers73,75, tetraaza macrocycles76 [for instance dibenzotetramethyltetraaza[14]annulene (TMTAA)], cyclic polyamines (polyazacycloalkanes)77-80 or, as already mentioned above, poly(pyrazolyl)borate were... 

Scheme 7. Cyclopropenylidene complexes of divalent germanium, tin, and lead.

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

Two factors combine to lend a greater diversity in the stereochemistries exhibited by bivalent germanium, tin and lead compounds, the increased radius of Mn compared with that of Mw and the presence of a non-bonding pair of electrons. When the non-bonding pair of electrons occupies the isotropic valence level s orbital, as in, for example, the complex cations Pb[SC(NH2)2]6+ and Pb[antipyrine]6+, or when they are donated to conductance band levels, as in the binary tin and lead selenides or tellurides or the perovskite ternary phases CsMX3 (M = Sn, Pb X = Cl, Br, I), then the metal coordination is regular. However, in the majority of compounds an apparent vacancy in the coordination sphere of the metal is observed, which is usually ascribed to the presence of the non-bonding pair of electrons in a hybrid orbital and cited as evidence for a stereochemically active lone pair . 

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

It is apparent from most of the examples previously described that the most common formal oxidation state found for the Group 14 element is E(IV) (E = Ge, Sn, Pb). Relatively few examples of divalent germanium, tin, or lead complexes have been described, and of these, many are not well characterized. Cobalt-containing compounds are no exception in this regard and there appears to be only one report in the literature that describes a species of this type, viz. [Ge Co(CO)4 2], 67, although the precise structure of this complex is unknown (77). Two main synthetic routes are described, Eqs. (4) and (S), the starting complex in the latter reaction being... 

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... 

We divided Section IV into three parts according to the three elements of Group 14 germanium, tin and lead. The main interest is the complexing chemistry of these elements. 

---