Germyl Cation Research Articles

A Free Cyclotrigermenium Cation with a 2pi-Electron System

The reaction of tetrakis(tri-tert-butylsilyl)cyclotrigermene with trityl tetraphenylborate in benzene produces tris(tri-tert-butylsilyl)cyclotrigermenium tetraphenylborate [(tert-Bu3SiGe)3+BPh4-], which can be isolated as a yellow solid that is stable in the absence of air. The crystal structure of the cyclotrigermenium ion reveals a free germyl cation with a 2pi-electron system. The three germanium atoms form an equilateral triangle similar to the carbon analog, the cyclopropenium ion.

Cyclotrigermenium Ion, a Free Germyl Cation with 2π-Electron System

The reaction of tetrakis(tri-t-butylsilyl)cyclotrigermene with trityl tetraphenylborate in benzene produced tris(tri-t-butylsilyl)cyclotrigermenium tetraphenylborate [(t-Bu3SiGe)3 +BPh4 -], which can be isolated as yellow solids stable in the absence of air. The crystal structure of the cyclotrigermenium ion reveals a free germyl cation with 2π-electron system.

Synthesis and Structure of a Bridging Germylidyne Complex: A Stable Germyl Cation

A three-coordinate, cationic germanium center is the unusual feature of this dimeric tungsten complex 1 generated by the thermolysis of [Cp2W(SiMe3)(GeMe2OTf)]. Delocalization of the charge onto only one of the tungsten centers is suggested by structural and orbital overlap considerations.

The structures, energies, vibrational, and rotational frequencies, and dissociation energy of GeH+5

Eight protonated germane structures (GeH+5) were examined in detail using the self-consistent field (SCF), configuration interaction including single and double excitations (CISD), and coupled cluster including single, double, and perturbatively included triple excitations [CCSD(T)] methods in conjunction with a double-ζ plus polarization (DZP) and a triple-ζ plus polarization (including f functions on germanium TZP+f) basis set. The C4v and the D3h isomers are high in energy [84 and 48 kcal mol−1, respectively, relative to the Cs(I) structure at DZP SCF]. Although structure Cs(I) is the global minimum, both Cs structures, where GeH+5 is comprised of a nearly planar germyl cation and a hydrogen molecule, are essentially equal in energy and allow virtually free hydrogen moiety rotation. Complete hydrogen scrambling does not occur, as the energy of the C2v(I) structure [33 kcal mol−1 (TZP+f CCSD)] is higher than the dissociation energy of GeH+5 into GeH+3 and H2 (D0=10 kcal mol−1). D0 of GeH+5 is almost the same as for SiH+5 due to a favorable highest occupied molecular orbital (HOMO) (σH2)−lowest unoccupied molecular orbital (LUMO) (pGe) interaction in GeH+5. The global minimum was characterized by vibrational frequency analyses (up to TZP+f CCSD), and we also report on the rotational constants as well as the proton affinity of germane (156 kcal mol−1).