Multinuclear (tin-119, carbon-13, deuterium) NMR spin-lattice relaxation studies on organo-tin compounds

Abstract

The carbon-13, tin-119 and deuterium MR spectra of a number of organo tin compounds have been detected by direct observation. The compounds fall into two main classes consisting of organo tin hydrides and organo tin chlorides. Tin-119 spin-lattice relaxation data for and nBu.Sn were measured, the first three over a temperature range. Measurements of tin-119 values were carried out with proton decoupling using, the inversion-recovery technique. NOE factors were measured by comparing spectra resulting from continuous and gated proton decoupling. For the n-alkyl tin compounds the T1 and HOE data indicated contributions to the total rate arising from the dipole-dipole interactions of tin-119 with remote protons. The competing mechanism was spin-rotation. T1 values were typically less than 5 seconds. Measurements of tin-119 T1 values in the hydrides were complicated by the magnitude of ( >1500 Hz) and only for nBuuSnH and Ph SnH have T and HOE factors n been determined. Carbon-13 T measurements have been made for factors have been determined for the last four molecules. Segmental motion was apparent in the n-alkyl chains. For rotation of the phenyl groups about the tin-carbon bond was indicated and the ratio of D /D has been determined.2The spin-lattice relaxation time of over a range of temperature was measured and the quadrupole coupling ponstant of deuterium in the bond was estimated as 88 +/- 10 kHz. The variation of the tin-119 chemical shift of with temperature and concentration has been investigated and the data can be adequately explained in terms of monomer-dimer equilibrium. Equilibrium constants and the enthalpy for the dissociation of the dimer have been evaluated. The tin-119 T1 and NOE data for this molecule at 1.4 and 2.3 T indicated a significant contribution to the relaxation from a field dependent mechanism.