Tetraethyl stannane: structure, conformations, and orientational order when dissolved in a nematic liquid crystalline solvent

Quantum chemical calculations are used to investigate the structure and the distribution of conformers of tetraethyl stannane, and these are compared with those of tetraethyl methane. The calculations predict that the most abundant conformers in tetraethyl stannane are those with symmetry C-1, in contrast to tetraethyl methane, in which the D-2d and S-4 conformers are dominant. The structural and conformational information on tetraethyl stannane are then used, together with the additive potential model, to explain the finite quadrupolar splittings observed in the deuterium NMR spectrum of tetraethyl stannane dissolved in a nematic liquid crystalline solvent. This analysis emphasizes that to understand the orientational order of a flexible molecule in a liquid crystalline phase it is essential to consider the symmetry of individual conformers rather than that of an average structure.