Tetramethyltin study by NMR spectroscopy in the gas and liquid phase

Tetramethyltin was studied by high-resolution NMR spectroscopy in liquid and gaseous states at 300 K. A small amount of this compound was introduced to the buffer gases: CO2 and N2O. Extrapolation of the gas-phase chemical shifts to the zero-density limit permitted the determination of 1H, 13C and 117/119Sn absolute nuclear magnetic shieldings in an isolated tetramethytin molecule. These new experimental results are useful for a reliable verification of the quantum chemical calculations of proton, carbon and tin nuclear magnetic shieldings in the molecule under study. The indirect spin–spin coupling constants were extracted from experimental spectra and compared with the values previously reported in the relevant literature. Intermolecular effects in the gaseous state, as well as in passing from gas to liquid are also found to be of essential significance here. The gas-to-liquid shifts measured are negative (deshielding) for proton and carbon but positive (shielding) for the tin nuclei.

► NMR chemical shifts of Sn(CH3)4 are linearly dependent on CO2 and N2O buffer gas density. ► New experimental nuclear magnetic shieldings of Sn(CH3)4 were estimated. ► The significance of intermolecular interactions Sn(CH3)4–CO2 and Sn(CH3)4–N2O in the gas phase was studied. ► The observed 1H, 13C and 117/119Sn NMR gas-to-liquid shifts were found. ► Scalar spin–spin nuclear coupling constants in gaseous and liquid Sn(CH3)4 were evaluated.