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.