New multinuclear experiments on solid organotin fluorides

(Bu3SnF)-Bu-71 and Mes(3)SnF (Mes = mesityl) are organotin fluorides that have direct Sn-F bonds. The Sn-119 and F-19 NMR spectra of these compounds have been measured using a selection of CPMAS probes. Doubly decoupled {H-1,F-19} as well as singly decoupled (H-1) Sn-119 NMR spectra are shown. Double decoupling gives higher resolution spectra and allows the sample of Mes(3)SnF 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 for Sn-119 NMR through reduced splittings when the F-19 decoupler power and offset were varied. Proton-decoupled F-19 spectra have been measured using a new HF double-resonance probe. In addition, two-dimensional heteronuclear correlation spectra are presented for Mes(3)SnF, allowing a full assignment for the F-19 and Sn-119 chemical shifts of the two sites. Full shielding tensor data are reported for both compounds. Values have been derived for the effective (Sn-119, F-19) dipolar coupling constants from both Sn-119 and F-19 experiments, yielding estimates of coupling anisotropy. (C) 1997 Academic Press.