Correlation among the gas-phase, solution, and solid-phase geometrical and NMR parameters of dative bonds in the pentacoordinate silicon compounds. 1-Substituted silatranes

Elena F Belogolova; Valery F Sidorkin

doi:10.1021/jp4035216

Correlation among the gas-phase, solution, and solid-phase geometrical and NMR parameters of dative bonds in the pentacoordinate silicon compounds. 1-Substituted silatranes

J Phys Chem A. 2013 Jun 27;117(25):5365-76. doi: 10.1021/jp4035216. Epub 2013 Jun 18.

Authors

Elena F Belogolova¹, Valery F Sidorkin

Affiliation

¹ A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky, 1, Irkutsk 664033, Russian Federation.

PMID: 23777391
DOI: 10.1021/jp4035216

Abstract

Silatranes XSi(OCH2CH2)3N exhibit a good linear relationship between their experimental and calculated (IGLO and GIAO) values of the NMR chemical shifts of (15)N, δN, and the lengths of dative bonds Si←N, dSiN, determined in the gas phase (ED, CCSD), solutions (COSMO PBE0, B3PW91), and crystals (X-ray). An aggregate of the obtained data provides strong evidence that the gas-phase value of dSiN in MeSi(OCH2CH2)3N should be greater by ∼0.05 Å than that determined in the electron diffraction (ED) experiment (2.45 Å). Given this condition, a long-standing contradiction between the data of the structural (X-ray, ED) and NMR (15)N experiments for the molecules of 1-methyl- and 1-fluorosilatrane regarding the sensitivity of their coordination contact Si←N to the medium effect is resolved.