PUB - Publikationen an der Universität Bielefeld

A series of different aryl-linked (frustrated) Lewis pairs with perfluoroethylsilyl and -stannyl functions as Lewis acids has been prepared. The 1,2-phenylene linked tin/phosphorus Lewis pair with a di-tert-butylphosphanyl unit as base shows a strong intramolecular donor-acceptor interaction, but still readily adds hydrogen chloride. At the same time, the analogous silicon/phosphorus Lewis pair could not be obtained due to the decomposition of at least one perfluoroethyl group. With a sterically more demanding 2,2,6,6-tetramethylpiperidine base, stable Lewis pairs could be obtained for both, silicon and tin. However, they do not show activity in small molecule activation with H-2, phenyl isocyanate, CS2 or SO2. Furthermore, 2-benzyl-linked tin/nitrogen and silicon/phosphorus Lewis pairs were synthesized. Studies on their reactions towards small molecules did not show any reactivity, probably caused by an unfavorable preorganization due to rotation of the benzyl position.