Structures and stability of Cl–M–N–H rings and cages (M = Si, Ge, Sn, Ti)

Abstract

Structures and thermodynamic properties of amido and imido monomer and oligomer compounds as potential single-source precursors for group 14 nitrides have been obtained at the B3LYP/DZP level of theory. The thermodynamic analysis shows that Cl₃MNH₂ amido compounds are stable with respect to both HCl elimination and oligomerization processes. In contrast, Cl₂MNH and ClMN species should undergo oligomerization. Formation of trimer compounds is more exothermic compared to the corresponding dimers. The M(IV) and M(II) cubanes are found to be the most promising precursors for group 14 nitrides: the ammonolysis reaction of cubanes is thermodynamically allowed in a wide temperature range for all M.

Keywords:

• monomer
• oligomer
• cubanes
• silicon
• germanium
• tin
• titanium

Acknowledgements

Excellent service by the Hochschulrechenzentrum of the Philipps-Universität Marburg is gratefully acknowledged. EID is grateful to the DAAD for a short-term fellowship. AYT is grateful to the Alexander von Humboldt foundation for financial support of his visit to Philipps-Universität Marburg. Work at St. Petersburg State University was supported by the Russian Foundation for Basic Research, grants 00-03-32566 and 01-03-06085.

Supporting Information

The total energies, sum of electronic and thermal enthalpies, and standard entropies of investigated compounds; predicted vibrational frequencies and IR intensities for investigated compounds; Cartesian coordinates for optimized structures of investigated compounds at the B3LYP/DZP level of theory.