Shielding anisotropy in tin compounds: spectroscopic studies of alkyltin cations in strong acid solutions

Abstract

We have observed that the 119Sn nmr spectra of dialkyltin cationic species in highly acidic solutions are strongly field dependent. Relaxation time measurements at three different magnetic fields have established that the dominant spin-lattice relaxation mechanism for these species at high magnetic field is shielding anisotropy. A comparison of T1−1 and T2−1 values indicates that at room temperature a rapid chemical exchange process is occurring. In the case of the (CH3)2Sn(SO3F)2–HSO3F system variable temperature 119Sn nmr reveals the presence of three tin species which are involved in this exchange process.