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 |1J(Si,H)| in SiHnCl4-n (n = 0−4) dissolved in THF-d8 is presented. We found |1J(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-d12. We also report on the variations in |1J(Si,H)| as a function of temperature, which we found to be linearly temperature dependent for the chlorine-substituted silanes and temperature independent for SiH4. Furthermore, the temperature dependence of |1J(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.