Organometallic Complexes of Siloles and Germoles

The first T -transition metal organometallic complexes 272 were made from Li(Me4C4ESiMe3) (E = Si, Ge) and Cp HfCl3 (98JA8245). Species 272 (E = Si) with trimethylphosphine forms the Hf-PMe3-adduct. 

Retention of configuration may be used for the synthesis of the intramolecular carbene complexes [87J0M(336)C1]. Methyl- or phenyllithium or di- 

Treatment of (1,1 -difluoro-2,5-diphenylsilacyclopentadiene)tricarbonyliron with a mixture of potassium fluoride and 18-crown-6 gives 279 [88JOM(347)Cl]. 

The polymeric species containing silole nuclei also form the Fe(CO)3 complexes T] -coordinated via the heteroring on interaction with Fe(CO)5 [93JOM(456)35 990M1717]. 

Silole reacts with Co2(CO)8 to form the monosubstituted p -silacyclopentadiene complex 286 [85JOM(293)295]. The 2,5-diphenyl analog of the latter with excess silole yields the corresponding disubstituted derivative 287 [87JOM(320)C7]. The similar complex was previously made for the 1,1-dimethyl derivative [76JCS(D)2484]. Treatment of 287 with iodine gives 288. 

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These considerations led to the preparation of the ti -coordinated complexes of siloles and germoles (94PAC1431). A number of facts in support of this view were obtained by X-ray determination of the structures of the organometallic derivatives of nontransition metals. Thus, the dianion of tetraphenylgermole forms a sandwich (Ulithium salt264 in dioxane at —20°C [96AG(E)1002]. At 25°C, however, the salt with a mixed coordination mode 265 results. Columnar structure is observed... 

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