Hybrid supports

Figure 3.8. An early example of a hybrid support applied in the rhodium catalysed hydroformylation operated in a continuous flow reactor. Polystyrene containing phosphite ligands were grafted on inorganic silica, such that the catalyst will behave as a homogeneous catalyst when using a compatible solvent...

Scheme 7.8 Generating a library of aryl ethers on a Tentagel-PAMAM hybrid support.

A first example of a polystyrene dendronized with a hyperbranched polymer was recently reported by Stumbe and Haag [36]. They synthesized a polystyrene-polyglycerol hybrid support (61) by coupling a hyperbranched polyglycerol (15)... 

One such organic-inorganic hybrid support has been synthesized by covalently anchoring a N-octyldihydroimidazolium cation fragment onto Si02 (denoted as... 

The immobilization of peroxidases can be classified in agreement with the support used for immobilization. In this way, three main types can be mentioned on organic, inorganic, and hybrid supports. Each of them displays their own characteristics that make them catalytically attractive and potentially applicable. Next, some examples and strategies are described. Additionally, peroxidases have been immobilized for their use in biosensors development with applications in diagnosis or electronics. These interesting and novel applications are covered in Chap. 6. 

A recent paper (286) reported the use of a commercially available soluble hybrid support prepared by copolymerization of styrene and allylic alcohol that exhibits a lipophilicity intermediate between that of PS and PEG chains. This support was grafted with a number of functional groups that were reacted with various monomer sets to produce pyrazolo[3,4-Z ]pyridines and coumarins with high yields and purities after precipitation by addition of ethanol or water. Most of the soluble support was recovered after the cleavage and retained the same efficiency in further reaction cycles. Another example is thoroughly described in the next subsection. 

Figure 3.12. Diagram illustrating the silica surface of unbonded and bonded Waters XTerra hybrid particles. Note that XTerra contains 50% less residual silanols by nature of its hybrid support chemistry. Diagram courtesy of Waters Corporation.

Scheme 4 Synthesis of high-loading PS-aryl ether dendrimer hybrid supports...

Recently, Haag and coworkers reported on the synthesis of polystyrene beads dendronised with a hyperbranched polymer [66, 67]. The polystyrene-polyglycerol hybrid support 5 was obtained by grafting of a hyperbranched polyglycerol directly onto a Merrifield resin [67] or alternatively polymerising glycidol directly onto a polyhydroxylated crosslinked polystyrene... 

Bokhari M.A., Akay G., Birch M.A., Zhang S. 2005. The enhancement of osteoblast growth and differentiation in vitro on a peptide hydrogel - PolyHIPE Polymer hybrid support material. Biomaterials, 26, 5198-5208 (in press). 

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