73Ge, NMR

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... 

See introductory remarks in Section I.A.4. Information on NMR spectra of organogermanium compounds appears in Table 2. Most sources usually include chemical shift values, S, and coupling constants, J, however, in many cases other features are also discussed. A general discussion of 73Ge NMR appeared in the literature57. 

Me4- Ge(CH=CH2) , n = 1-4 1H. 13C and 73Ge NMR. Good correlation for chemical shifts with those of Si analogues. Some discrepancy with MNDO calculations. 67... 

FIGURE 37. Comparison of calculated and experimental 73Ge NMR chemical shifts of some simple germanium compounds. The experimental values of GeMe4 nCln (n = 1-3) were not available. They have been estimated from the analogues silicon compounds using empirical correlation factors. Reproduced by permission of John Wiley Sons, Inc. from Reference 158... 

In recent years a number of 73Ge chemical shifts were published. However, the method has still a vast number of limitations and therefore only a few hundred compounds are characterized by 73Ge NMR. Earlier reviews concerning 73Ge NMR chemical shifts are given in the literature8-12. 

The progress in calculating NMR chemical shifts of heavier nuclei made it possible to calculate 73Ge and 119Sn NMR chemical shifts. Figure 37 shows the comparison of... 

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