A single, broad singlet is observed at 3.2 ppm at room temperature in the solution state phosphorus nuclear magnetic resonance (PNMR) of ((Dipp)P)Ge. This signal is consistent with rapid exchange between the planar and pyramidal phosphorus centers. As the temperature is reduced to -80 C, the signal becomes two broad, equal intensity singlets at -42.0 ppm and 8.0.
Two peaks with isotropic chemical shifts of 81.9 and -61.6 ppm, in a 1:1 ratio are observed in the solid state PNMR. No other signals are observed in the PNMR. In general diphosphagermylenes with pyramidal phosphorus centers exhibit a chemical shift close to those of free phosphine. In addition, planar phosphorus centers of Ge=P compounds generally have a downfield PNMR shift. Consequently, peaks at 81.9 and -61.6 ppm have been assigned as planar and pyramidal phosphorus centers of ((Dipp)P)Ge, respectively. This has been supported by DFT calculations that predict PNMR shifts of planar and pyramidal phosphorus centers of ((Dipp)P)Ge are at 100 and -61 ppm.