Germyl cations

In the field of germyl cations, several remarkable examples were recently reported. Thus, the transient germyl cation, prepared as shown in Scheme 2.5, B (Section... 

By contrast, in the formally aromatic 277-electron system of 9886 [Eq. (20)] the average Ge-Ge bond distance is 2.326(4) A (98a) and 2.335(2) A (98b), thus 0.1 A shorter than in the anion 97.81 The three germanium atoms of this free germyl cation form an equilateral triangle. 

The intramolecular stabilization of germyl cation 34 by a remote aryl substituent was demonstrated by the NMR chemical shifts of the coordinated aryl ring. The chemical shift pattern found for the coordinated arene ring of 34 is characteristic for arenium ions and it closely resembles that found bissilylated arenium ions 78. 

While for silyl and germyl cation complexes tetracoordination of the element prevails, stannyl cations favor pentacoordination. That is, the trigonal-bipyramidal environment of the Sn atom in the diwater complex of the stannylium ion Me3Sn ... 

Nevertheless, the germyl cation is more stable than die silyl cation by 18.8 kcal moP [DZP CCSD, Equation (10)], with respect to the tetrahydrides. Germane has the highest... 

While germyl cations are not known in aqueous solutions, reports on the formation of stannyl cations appeared as early as 192324. Since then, numerous investigations25-27 established that ions of the type R3M(OH2)n+ (M = Sn, Pb) can be prepared in aqueous solutions. The early literature on this subject was reviewed in 1966 by Tobias28. Among earlier studies one should mention a series of publications by the group of Rabenstein29,30 who studied plumbyl cation complexes in aqueous solutions by H NMR. 

Oxidation of cyclotrigermenes — formation of the free germyl cation... 

The unusual hydrated germyl cation structure of complex 123c H2O is discussed in Section VIII.A. 

While for silyl and germyl cation complexes tetracoordination of the element prevails, stannyl cations favor pentacoordination. That is, the trigonal-bipyramidal environment of the Sn atom in the diwater complex of the stannylium ion Me3Sn + [Me3Sn(H20)2]+ 84178 has its counterpart in the tetrahedral structure of the pro-tonated silanol 85.116 The structure of the bis(acetonitrile)tricyclohexyltin hexa-fluoroantimonate 86 SbF6179 reveals pentacoordination for the tin atom,180 while all... 

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