Polymer-immobilized ligands

The development of polymer-immobilized ligands and catalysts for asymmetric synthesis is a rapidly growing field [1], which has great importance due mainly to the easy separation and recyclability of polymer-supported catalysts. The polymeric catalysts also represent one of the most powerful tools for green sustainable chemistry, in the sense that they can be easily recovered and reused many times. 

N. V. Bovin and H.-J. Gabius, Polymer immobilized carbohydrate ligands versatile chemical tools for biochemistry and medical science, Chem. Soc. Rev., 24 (1995) 413—421. 

El Ashgar used a variation on the technique [16]. Specifically, 3-chloropropyltrimethoxysilane was used to alkylate diethylenetiiamine, i.e, reaction with the halide end to produce a precursor of a polymer (I, Eqn. 1). The reaction of I with tetraethylorthosilicate resulted in a "diethylenetiiamine polysiloxane immobilized ligand system."... 

Polymer-immobilized complexes with heterocyclic ligands as catalysts 92UK257. 

Recently, another variation on this theme was presented. By introducing PEG-modified affinity sorbents (Sepharose beads carrying the immobilized ligand) a new process configuration for protein purification was achieved as shown in Figure 2 (32). The beads were exposed to the cell homogenate before the phase components were added. After phase separation the particles were recovered from the top phase, as a layer on top of the interface. The beads were collected and transferred to a column, where they were washed free of the phase polymers, and then the elution was carried out according to conventional procedures. 

Styrene-divinyl benzene resins have been used as typical support for the metal containing catalysts bound to them. The synthesis of these polymeric reagents has involved several approaches depending on the application which they are intended. The immobilization of transition metals on polymer supports involves using polymers containing ligands which can complex with the metal such that the coordination sphere of the metal remains essentially the same as in... 

Poly(ethylene oxide)s are the only water-soluble polymers which can be terminally functionalized and from which we can obtain complexes bound to the polymer tail. Thereby, several problems encountered in producing conventional polymer-immobilized catalysts can be obviated. The metal complexes synthesized retain the properties of, on the one hand, homogeneous low molecular weight metal complexes, and on the other, poly(ethylene oxide)s or ethylene oxide-propylene oxide block copol)miers. Among these properties are, first of all, water solubility and also the ability to concentrate nonpolar substances in polymer globules or micelles formed by polymer ligands. 

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