ja005774u_si_001.pdf (222.12 kB)
Noncovalently Functionalized Dendrimers as Recyclable Catalysts
journal contribution
posted on 2001-08-07, 00:00 authored by Debby de Groot, Bas F. M. de Waal, Joost N. H. Reek, Albertus P. H. J. Schenning, Paul C. J. Kamer, E. W. Meijer, Piet W. N. M. van LeeuwenThe efficient reversible functionalization of the periphery of urea adamantyl poly(propylene imine)
dendrimers with catalytic sites using noncovalent interactions is described. Phosphine ligands equipped with
urea acetic groups, a binding motive complementary to that of the dendrimer host, have been prepared and
assembled to the dendrimer support. The resulting supramolecular complex has been used as a multidentate
ligand system in the palladium-catalyzed allylic amination reaction in a batch process and in a continuous-flow membrane reactor. We found that the activity and selectivity of the dendrimeric complex is similar to
that of the monomer complex, which indicates that the catalytic centers act as independent sites. The size of
the supramolecular system is sufficiently large and the binding of the guests is strong enabling a good separation
of the catalyst components from the reaction mixture using nanofiltration techniques.