Existence of an intradimeric rearrangement in monofunctional tetrabutyldistannoxanes [Bu 4Sn 2X 2O] 2 probed by multinuclear NMR spectroscopy in solution and in solid state

Abstract

A set of 1-D and 2-D, 13C- and 119Sn-NMR experiments—both in solution and in the solid state—exhibit a common peculiarity of the monofunctional tetrabutyldistannoxanes of general formulae R 4Sn 2X 2O in comparison with the no problematic NMR data of difunctional tetrabutyldistannoxanes R 4Sn 2XYO. Relying on the support of these observations, the existence of a dynamic process is evidenced in solution. This process, rapid and equilibrated at ambient temperature, is shown to be frozen both in solution at 188 K and in the solid state. A mechanism of intramolecular rearrangement of the distannoxane dimeric form is discussed on the basis of modelisation of the movements required. It accounts for all spectroscopic observations and is not expected to occur with the dimer form of the difunctional distannoxanes (X≠Y).