Journalartikel

Jahr der Veröffentlichung: 1996

Seiten: 10635-10639

Zeitschrift: Journal of the American Chemical Society

Bandnummer: 118

Heftnummer: 43

DOI Link: https://doi.org/10.1021/ja9616701

Verlag: American Chemical Society

Abstract: 

Ab initio quantum mechanical methods were applied to examine M₂(GaH)₃ (M = Li, Na, K) compounds, which are models for the newly synthesized class of Ga₃ three-membered-ring cyclogallene compounds. Basis sets of triple-ζ plus double polarization augmented with diffuse functions (TZ2P+diffuse) quality were employed at the self-consistent field (SCF) and density functional theory (B3LYP) levels of theory. Computed equilibrium geometries, harmonic vibrational frequencies, and chemical shifts are reported. The experimental (X-ray) structures of cyclogallenes are in close agreement with theory. While Na₂(GaH)₃ possesses C₃ symmetry (the deviation from C3h symmetry is very small), the remaining two compounds are C_3h symmetric. The parent neutral three-membered-ring structure (GaH)₃ is not stable as the imaginary vibrational frequencies of (GaH)₃ lead to Ga−Ga bond breaking. Upfield changes in the chemical shifts for the alkali metal atoms over and under the ring plane are taken as strong evidence for ring currents in the cyclogallene moiety. This finding and the large negative nucleus independent chemical shifts (NICS) clearly support the proposed aromatic character of the title compounds.

Harvard-Zitierstil: Xie, Y., Schreiner, P., Schaefer, H., Li, X. and Robinson, G. (1996) Are Cyclogallenes [M2(GaH)3] (M = Li, Na, K) Aromatic?, Journal of the American Chemical Society, 118(43), pp. 10635-10639. https://doi.org/10.1021/ja9616701

APA-Zitierstil: Xie, Y., Schreiner, P., Schaefer, H., Li, X., & Robinson, G. (1996). Are Cyclogallenes [M2(GaH)3] (M = Li, Na, K) Aromatic?. Journal of the American Chemical Society. 118(43), 10635-10639. https://doi.org/10.1021/ja9616701