Pentacoordinated Organo and Hydrido Cyclic Silanes via Sulfur Donor Action1

Autor:	Ramil-Marcelo L. Mercado, Roberta O. Day, Robert R. Holmes, A. Chandrasekaran
Rok vydání:	1999
Předmět:	Silanes Organic Chemistry Diol Activation energy Ring (chemistry) Photochemistry Medicinal chemistry Inorganic Chemistry NMR spectra database Trigonal bipyramidal molecular geometry chemistry.chemical_compound chemistry Proton NMR Pseudorotation Physical and Theoretical Chemistry
Zdroj:	Organometallics. 18:906-914
ISSN:	1520-6041 0276-7333
DOI:	10.1021/om980751y
Popis:	The new cyclic organosilanes S(C10H6O)2SiMe2 (1) and S(C10H6O)2SiPh2 (2) were obtained by the reaction of R2Si(NMe2)2 (R = Me, Ph) with thiobis(2,2‘-naphthol), while S[Me2C6H2O]2SiH(Me) (3) and S[(t-Bu)MeC6H2O]2SiH(Me) (4) were formed by reaction of Cl2SiH(Me) with the appropriate diol in the presence of Et3N. Characterization was achieved by 29Si and 1H solution NMR, 29Si solid-state NMR, and X-ray structural studies. As a result of sulfur donor interaction, pentacoordinate geometries were obtained where 3 and 4 were displaced further toward a trigonal bipyramid (TBP) compared to 1 and 2. Variable-temperature NMR spectra showed 1 to be fluxional with an activation energy of 9.4 kcal/mol. An exchange mechanism involving rupture of the Si−S donor interaction accompanying a ring pseudorotation is postulated. The less symmetric silanes 3 and 4 do not exchange, as indicated by the 1H NMR data. Comparison of the degree of Si−S donor interaction of 1−4 with that of related cyclic organosilanes possessing Si−O a...
Databáze:	OpenAIRE
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