Germylenes stable structures

Four new stable digermenes 66-69 were synthesized from dichlorogermanes and sodium in toluene or lithium naphthalenide (Scheme 10). 66 and 68 have been characterized by X-ray61 (see Section III,B,1). 66-6851 keep their digermene structure in solution, in contrast to 6960 (probably the E isomer due to the steric hindrance in the Z isomer), for which an interconversion with the corresponding germylene was observed. 

As for stable diarylgermylenes, three examples (146, 147, ° and 148, Scheme 14.65) have been structurally analyzed by X-ray crystallographic analysis. The solid-state structure of germylene 146 indicated that its remarkable stability is mainly the result of intramolecular coordination of the fluorine atoms of the -CF3... 

Electronic structure of stable carbenes, silylenes and germylenes... 

Besides the triatomic CAs, the molecular structures have been determined experimentally for only labile silylidene and germylidene, as shown in Table 10. At the same time most of the stable CAs have been characterized by X-ray analysis or by electron diffraction. The available structural data for some stable germylenes, stannylenes and plumbylenes have partly been presented in Section IV. The comprehensive consideration of the geometries of stable CAs is beyond the scope of the present review. 

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