Molecular motion in tetraphenyltin studied by NMR

NMR second moment and spin-lattice relaxation times in the laboratory (60 a nd 25 MHz) and in the rotating frame (B-1 = 2.1 mT) were studied for polycr ystalline tetraphenyltin Sn(C6H5)(4) in a wide temperature range. Two kinds of motions were detected: isotropic rotation of whole molecules and reorie ntations/oscillations of phenyl rings. A dependence of the potential energy of the molecule in the crystal on the angle of the phenyl ring rotation ab out the Sn-C bond was obtained on the basis of atom-atom calculations. The amplitude of the ring-oscillations at 133 K was estimated as +/-7 degrees. Below room temperature the magnetisation recovery is significantly non-expo nential, which may be interpreted as due to the correlated motion of phenyl rings.