Structures and intramolecular motions of special polycyclic germanium(II) amides

Article abstract of DOI:10.1002/zaac.19966220907

Compounds of the general formula MeSi(NtBu)₃Ge₂X (X = Cl (1), N(SiMe₃)₂ (2), P(C₆H₅)₂ (3)) have been synthesized and characterized by X-ray structure analyses and multinuclear NMR-spectroscopy. The temperature dependent NMR investigations of 2 in solution show bond fluctuations concerning the metal-nitrogen bonds and ElMe₃ (El = C, Si) rotations. Some of these intramolecular motions also occur in the solid state as detected by means of temperature dependent ¹³CCP/MAS NMR spectroscopy. The special nature of these NMR spectroscopically detected movements in solution are compared with the results of the X-ray structure analyses. A model of the dynamical behaviour of 2 in solution suggests a quasi circular movement of the two germanium atoms within the molecular cage. After the phase transition from solution to the solid state at ambient temperature this special metal fluctuation is stopped. In the solid state the rotations of the SiMe₃ groups in 2 are only hindered at low temperatures. Johann Ambrosius Barth 1996.