Non-metal containing dendrimers

7 METALLODENDRITIC CATALYSTS AND MEMBRANE CATALYSIS CATALYST RECOVERY 

The globular shape of dendritic macromolecules with a persistent nanosize and radius should allow easy separation or retention by ultra- or nanofiltration membranes. This concept of separating the catalysts from the product/substrate 

Compound(s) Reference Complexed Catalyst metal (mol %) In situ prepared Discrete catalyst Metal chelaton  

An interesting novel approach to the synthesis of (metallo)dendrimer catalysts could be the use of random hyperbranched polymers [38]. Obviously, these hyperbranched polymers have comparable but less defined structures, but to arrive at dendrimers with similar sizes, a larger number of preparative steps are required, which may be an economic disadvantage. Furthermore, materials involving heterogeneous supports with well-defined metallodendritic subunits [15] can be a promising future direction giving rise to new types of supramolecu-lar catalysts that can easily be recovered from production streams. 

The future will undoubtedly show considerable activity in the field of (metal-lo)dendrimers, not only because of the beauty of the structures and the synthetic challenge their preparation involves, but also because of their usefulness in fundamental applications and applied science. Finally, while we are learning to design, synthesize and apply these multimetallic catalytic objects (either soluble or insoluble), other challenges may include preparation of multifunctional catalytic prototypes by including, e.g. a substrate recognition function next to the catalytically active site. 

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