Germanium protonation

There are a few isolated cases of the addition of amines, thiols, carboxylic acids, and a phosphorus ylide to doubly bonded germanium compounds. Again, the reactions are regioselective, with the nucleophilic portion of the weak acid adding to the germanium and the proton adding to the heteroatom. 

The triaryl radicals of germanium exhibit lower g values than their trialkyl counterparts. In part, this arises from increased delocalization of the unpaired spin density onto the aryl rings (and the Ar3Ge radicals do show hyperfme coupling to the ring protons). For example, spin densities for the radicals PhmMe3 mGe, calculated by the Hiickel method (Table 2), reveal that there is a linear correlation between the g value of the radical and... 

You could swallow a capsule of germanium, Ge (atomic number 32), without ill effects. If a proton were added to each germanium nucleus, however, you would not want to swallow the capsule. Why (Consult a periodic table of the elements.)... 

While much of the preceding is speculative, it is no more speculative chemically than Mendeleev s predictions of gallium (eka-afuminum) and germanium (eka-silicon). The speculation centers on the possible or probable stability of nuclei with up to twice as many protons as the heaviest stable nucleus. The latter falls outside the realm of inorganic chemistry, but the synthesis and characterization of some of these elements would be most welcome. 

The characteristic structural features of two-coordinate low-valent germanium cation 276 are similar to those of the analogous Si cation 268 discussed above. The average C—N and C—C bond distances (1.348 A and 1.392 A, respectively) and the essentially planar ring indicate aromatic delocalization.691 In contrast, however, the y-CH proton (8 H 4.23) is more shielded. The aromatic substituents are perpendicular to the GeN2C3 plane. 

In the 80 MHz H-NMR spectrum of Sn(OMC)Cl, and in the analogous germanium complex, the meso-protons appear as two signals while in the spectra of the acetate derivatives a single resonance has been observed. No linewidth data have been reported and the results have been explained considering that the behavior of acetate as a bidentate ligand, discussed in Sect. 4.2, would introduce distortions into the molecule causing accidental isochrony of the meso-proton resonances. 

Fig. 1. (Top) y-Ray energy spectrum of the reaction 19F(p,ay)160 measured by a 3-inch Nal detector. Proton energy is 2.7 MeV, sample material is fluorapatite. (Middle) y-Ray energy spectrum for the same reaction acquired by a high purity germanium detector. The sample is meteoritic material. Low energy lines from several other nuclear reactions can be identified. (Bottom) Low-energy y-ray spectrum from 19F(p,p y)19F inelastic scattering recorded with a thin Ge(Li) detector. Reproduced with permission from Grambole and Noll [59],...

This unusual reaction has been proposed to occur via a four-center mechanism131. While no structural information was derived from the original experiments, calculations at the HF level predict that a linear structure corresponding to protonated germanium oxide, GeOH+, is considerably more stable than the alternative linear HGeO+ structure151. 

A germanium complex with ethylenediaminetetraacetic acid (Hedta) 532 has a pen-tadentate edta ligand with one protonated acetate group which does not coordinate, forming a six-coordinate complex1150. 

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