Stannylene acetals trimeric

These compounds are less aggregated in solution. For instance, 2,2-dibutyl-l,3,2-dioxastannolane, a polymer in the solid state, has been shown, by variable temperature Sn NMR spectroscopy, to be a mixture of dimers, trimers, and tetramers in solution, with dimers predominating at room temperature and above. This technique has also indicated that most carbohydrate-derived stannylene acetals are present predominantly as dimers in solution." " " Supporting evidence has been obtained from mass spectral studies and by comparison of solid-state NMR spectra with those of solutions." Some dibutylstannylene acetals derived from cw-diols contain an observable proportion of higher oligomers benzyl 4,6-0-benzylidene-2,3-0-dibutylstannylene-o -D-mannopyranoside is present as a mixture of a dimer and a trimer in chloroform-d at -60 °C but, in the less polar solvent toluene-dg, is mainly present as a tetramer at that temperature. ... 

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