Synthesis and Applications of Organotin Clusters with Multi-Layered Structure

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Novel fluorodistannoxanes [XR^F_2SnOSnR^F_2Y]_2(R^F=C_6F_<13>C_2H_4;C_4F_9C_2H_4,X,Y=Cl,Br,NCS) were synthesized. As expected, these compounds were highly fluorophilic and thus exhibited high partition coefficients for the fluorous solvents when dissolved in a binary flurous/organic solvent mixture. The fluorous biphasic (trans)esterification by use of these catalysts enabled quantitative recovery of the catalysts, hence allowing the recycled use more than 20 times. More importantly, the reaction proceeded in 100% conversion and yield even by use of reactants in a strict 1:1 ratio. This means that the fluorous biphasic technology enabled the perfect conversion of the equilibrium reactions, which had be been realized before.Next, the chlorine atoms in the above compounds were replaced by C_8F_<17>SO_3 and (C_8F_<17>SO_2)_2N with the hope to further increase the fluorophilicity. The desired compounds were obtained as hydrates, but they were not completely insoluble in fluorous solvents in contrary to our expectation. On the hand, they were soluble in polar organic solvents and, to our surprise, they preferentially dissolved in fluorous solvents when exposed to a binary mixture of fluorous and polar organic solvents. This anomaly was explained by replacement of hydrated water with polar organic solvents. Based on this character, fluorous distannoxanes proved to work as fluorous surfactants.