Polymer-mediated synthesis, dendrimers

Polyethylene, implant material, 145 Polymer-mediated synthesis, dendrimers, 14-15... 

The structure of cationic lipids and polymers is readily amenable to chemical modification [35, 36] allowing the exploration of a virtually unlimited number of combinations and strategies at the mercy of chemists creative abilities. Various reviews have been focused on cationic lipids, dendrimers and polymers in terms of their chemical structures and their transfection properties [36—41], in an attempt to shed some light on the chemical requirements necessary to mediate gene delivery. The focus of this chapter will be to explore these carriers from a synthetic perspective, with a description of the chemical strategies used for the preparation via synthetic organic chemistry (excluding polymer synthesis) of cationic lipids and dendrimers. 

A number of research groups have reported the preparation of a large number of star-shaped molecules and dendrimers containing ferrocenyl or arene cyclopentadienyliron complexes at the core or the peripheries.300-320 A number of these dendrimers were prepared via cyclopentadienyliron-mediated per-alkylation, -benzylation and -allylation reactions of cationic tri-, tetra- and hexamethylbenzene complexes. These dendrimers were multifunctional materials and have been used in the synthesis of branched organic and organometallic polymers. 

The synthesis and properties of star polymers and dendrimers functionalized with ferrocene units has attracted a great deal of attention. The synthesis of high-generation dendrimers functionalized with chiral ferrocenyl units in their structures has been reported. The chiroptical properties of this class of dendrimer was dependent on the number of ferrocenyl groups and their chemical environment, but not on their position within the dendrimer. Deschenaux has reported the synthesis of hquid crystalline ferrocene-based polymers prossessing an enantiotropic smectic A phase. Ferrocene-functionahzed cyclic siloxane (29) and silsesquioxane branched polymers have also been reported. A hyperbranched polymer with a cubic silsesquioxane core was used to mediate the electrocatalytic oxidation of ascorbic acid. 

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