New Multinuclear Experiments on Solid Organotin Fluorides

Abstract

nBu3SnF and Mes3SnF (Mes = mesityl) are organotin fluorides that have direct Sn–F bonds. The119Sn and19F NMR spectra of these compounds have been measured using a selection of CPMAS probes. Doubly decoupled {1H,19F} as well as singly decoupled {1H}119Sn NMR spectra are shown. Double decoupling gives higher resolution spectra and allows the sample of Mes3SnF to be spun slower to give more spinning-sidebands without overlapping of signals, giving improved analysis. The doubly decoupled spectra are sensitive to the power and offset of the decouplers. The effect of off-resonance decoupling has been observed for119Sn NMR through reduced splittings when the19F decoupler power and offset were varied. Proton-decoupled19F spectra have been measured using a new HF double-resonance probe. In addition, two-dimensional heteronuclear correlation spectra are presented for Mes3SnF, allowing a full assignment for the19F and119Sn chemical shifts of the two sites. Full shielding tensor data are reported for both compounds. Values have been derived for the effective (119Sn,19F) dipolar coupling constants from both119Sn and19F experiments, yielding estimates of coupling anisotropy.