THE FIRST CATHODICALLY GENERATED TETRAALKYLAMMONIUM-TIN COMPOUNDS

The reduction products of tetramethylammonium (TMA(+)) and dimethylpyrrolidinium (DMP(+)) at a tin cathode were isolated and examined in the solid-state for the first time. The empirical formula of R(4)N-metals derived from tin is R(4)N(Sn-x), where x is equal or close to 5. Existence of R(4)N(+) cations and negatively charged tin particles within the structure was demonstrated. Isolated TMA(Sn-5) is a deep red solid while DMP(Sn-5) is dark gray. They show a weak electron spin resonance signal, but the bulk material is diamagnetic as in the case of DMP(Pb-5). X-ray powder diffraction patterns of DMP(Pb-5) TMA(Sn-5), and DMP(Sn-5) were generated. We fmd that the lead compound shows the elemental lead diffraction pattern, suggesting charged metal particles, and the tin compounds show no diffraction lines, consistent with charged metal clusters, of size less than 50 Angstrom arranged in a noncrystalline morphology. We concluded that these materials should not be considered molecular; i.e., they are not composed of discreet metal clusters, (M(5))(-) or (M(10))(2-), but Of larger er aggregates (nanoclusters or nanocrystals) approaching the structure of the bulk metal.