Datensatz

Zusammenfassung

Quantum chemical calculations at the semi-empirical, Hartree-Fock and correlated ab initio levels have been carried out to rationalize structure, bonding and reactivity of stable cyclic diaminosilylenes and -germylenes. Theory shows excellent agreement with experimental X-ray and electron diffraction data. The calculated thermochemical data provide a consistent description of chemical vapour deposition from a cyclogermylene precursor. Electronic stabilization via p_π–p_π delocaliiation is an important bonding feature in aminosubstituted silylenes and germylenes. The aminogermylenes have singlet ground states with the lowest triplet states at least 40 kcal/mol higher in energy. In contrast to the homologous aminocarbenes, aminosilylenes and -germylenes are thermodynamically stable with respect to their tetravalent isomers. Planar 2-germaimidazoles are predicted to be unstable. Theoretical data for four different types of Ge–N bonds are compared.