An experimental and theoretical study of spin-spin coupling in chlorosilanes.
An experimental and theoretical study of the absolute value of the one-bond spin-spin coupling constant |(1)J(Si,H)| in SiH(n)Cl(4-n) (n = 0-4) dissolved in THF-d(8) is presented. We found |(1)J(Si,H)| to increase with an increasing number of chlorine substituents, and the quantitative changes were found to differ from the values previously reported for the same compounds dissolved in cyclohexane-d(12). We also report on the variations in |(1)J(Si,H)| as a function of temperature, which we found to be linearly temperature dependent for the chlorine-substituted silanes and temperature independent for SiH(4). Furthermore, the temperature dependence of |(1)J(Si,H)| varied between the different chlorosilanes. Solvent-solute interactions were studied by quantum chemical DFT calculations. The variations in chloro-silane bond lengths upon adduct formation and the different adduct interaction energies may explain the temperature dependences of the coupling constants.
Thorshaug
Knut
K
Department of Hydrocarbon Process Chemistry, SINTEF Materials and Chemistry, P.O. Box 124, Blindern, N-0314 Oslo, Norway. knut.thorshaug@sintef.no
Swang
Ole
O
Dahl
Ivar M
IM
Olafsen
Anja
A