Germanium double bonded compounds

Until recently, there have been only two examples of stable Ge-S double bond compounds and one each for Ge-Se and GE-Te double bond compounds, but both of them are stabilized by the intramolecular coordination of a nitrogen ligand to the germanium center. 

Heteroatom-Substituted Germanium-Chalcogen Double Bond Compounds... 

The existence of a germanium-carbon pjr-pjr double bond in the intermediate complex is likely. The intermediate was not isolated as such, but as its dimer. Compounds containing a carbon-germanium double bond were prepared by Satg6 and coworkers59, like the fluorenylidenedimethylgermanium, where stabilization arises from change transfer in the aromatic system. 

Reactivity of stable germanium-nitrogen double bond compounds has been widely documented in previous reviews.3,4,6,7,119... 

Conjugated double-bond compounds containing germanium. 869... 

Table 5 shows the structural and spectral data of tetra- and pentacoordinate double-bond compounds between germanium or tin and group 16 ele-... 

Unstable compounds with double-bonded silicon and germanium atoms... 

Unstable compounds with double-bonded silicon and germanium atoms (silenes, silanones, germanones, germathiones)... 

Compounds containing double-bonded silicon and germanium atoms are the nearest analogues of olefins, ketones and thioketones. However, most of them are very unstable and highly reactive species. 

Although no 73Ge NMR spectra of stable doubly bonded germanium compounds have been recorded, NMR chemical shift data for the heteroatom of the double bond are available these are listed in Table II. The chemical shift of the, sp2-hybridized carbon atom of dimesitylneopentylger-mene (entry 1, Table II), without any polar substituents, falls at 8 124.2.26 The chemical shifts of the boron-substituted sp2-hybridized carbon atoms of two stable germenes (entry 2, Table II) fall in the upfield region of the... 

With the availability of stable geometric isomers of doubly bonded germanium compounds, experimental determinations of the 7r-bond strength can be made. The enthalpy of activation for double bond isomerization in Mes(Tip)Ge=Ge(Tip)Mes (Tip = 2,4,6-triisopropylphenyl) has been determined for the Z-E conversion, 22.2 . 3 kcal/mol and for the E-Z conversion, 20.0 0.3 kcal/mol.15 These values agree well with recent theoretical estimations.7 The isomerization barrier in germaphos-... 

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