Cyclophane coordination polymers

With these features in mind, we envisioned a new family of macrocyclic ligands for olefin polymerization catalysis (Fig. 9) [131, 132], We utilized macrocycles as the ligand framework and installed the catalytic metal center in the core of the macrocycles. Appropriate intra-annular binding sites are introduced into cyclophane framework that not only match the coordination geometry of a chosen metal but also provide the appropriate electronic donation to metal center. The cyclophane framework would provide a microenvironment to shield the catalytic center from all angles, but leaving two cis coordination sites open in the front one for monomer coordination and the other for the growing polymer chain. This could potentially protect the catalytic center and prevent it from decomposition or vulnerable side reactions. 

Representatives of structure type C are also realized (M = Cr°, Fe " ) exchange of both benzene rings by cyclopentadienyl rings leads to the family of ferrocenophanes (fcp), of which a large number of representatives are known. Interesting electrochemical properties are to be expected with structure type D. The syntheses of several monomeric units, where a metal atom is coordinated to two cyclophane ligands (M = Cr , Fe, Ru ), constitute a partial success on the way to a corresponding polymer (n = oo). 

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