X-ray diffraction studies of three 1-phenylethynylgermatranes with two phenyl groups in atrane skeleton

Single crystal structures of treo-N(CH2CH2O)2(CHPhCHPhO)GeCCPh (1), erythro-N(CH2CH2O)2(CHPhCHPhO)GeCCPh (2) and N(CH2CH2O)2(CH2CPh2O)GeCCPh (3) were determined by X-ray diffraction studies. These compounds show transannular N→Ge interactions; the strength of this interaction depends on the Ph groups position in atrane skeleton (1, d(N→Ge)=2.210(4) Å; 2, d(N→Ge)=2.166(4) Å; 3, d(N→Ge)=2.138(3) Å). The structures of these compounds are discussed along with performed DFT calculations data. General trends for molecular structures of the group 14 elements (Si, Ge) metallatranes containing carbon substituents in atrane framework are reviewed.