Phosphorus Functionalized Dendrimers and Hyperbranched Polymers: Is There a Need for Perfect Dendrimers in Catalysis?
Article first published online: 10 MAR 2010
Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Israel Journal of Chemistry
Special Issue: Dendrimers and Related Compounds
Volume 49, Issue 1, pages 79–98, May 2009
How to Cite
Ribaudo, F., Van Leeuwen, P. W. N. M. and Reek, J. N. H. (2009), Phosphorus Functionalized Dendrimers and Hyperbranched Polymers: Is There a Need for Perfect Dendrimers in Catalysis?. Isr. J. Chem., 49: 79–98. doi: 10.1560/IJC.49.1.79
- Issue published online: 10 MAR 2010
- Article first published online: 10 MAR 2010
- Manuscript Accepted: 4 NOV 2008
- Manuscript Received: 21 JUL 2008
In this paper we describe the facile and straightforward covalent functionalization of commercially available dendritic poly(propylenimine) and hyper-branched poly(ethylenimine) with P-containing functional groups. The P-functionalized macromolecules have been applied as multivalent ligands in the Pd-catalyzed allylic substitution reactions (batch and continuous process) using either morpholine or thiophenol as nucleophile. Palladium complexes of all described molecules are active in allylic substitution reactions. The PEI functionalized polymers appear more sensitive to small changes in the P/Pd ratio than the PPI analogues, but form catalysts that are more active. When used in a continuous flow process the macromolecules are completely retained by the nanofiltration membrane, while the catalytic activity decreases with time because of palladium depletion. This is more severe for the allylic thiolation, probably because of the stronger affinity of sulfur for palladium, facilitating palladium leaching.