Multinuclear systems polymer

Most of the systems described in Chapter 5 contain small- or medium-sized or multinuclear benzenoid and non-benzenoid arenes. In Chapter 6, Hoger gives an overview over the mastery of the synthesis of macro- and megacycles. He shows different approaches towards shape-persistent macrocycles and carefully examines and discusses selected examples that display the advantages and disadvantages of macrocycle synthesis under kinetic and thermodynamic control. The template approach (both supramolecular and covalent) towards functionalized rings is also discussed and introduces a strong motif of supramolecular chemistry, which is much further developed but in a more polymer-oriented topic, in the next chapter. 

Catalysts obtained from metal alkyl and a bi- or trifunctional protic compound, e.g. in systems such as AlEt3—H20 [17], ZnEt2—H20 [16] and ZnEt2—Ar(OH)3 [31], which are characterised by the appearance of associated multinuclear species with condensed metal atoms ( Mt—O—Mt—O ), also form epoxide polymers with a very high molecular weight and broad molecular weight distribution therefore, in this case also, only a small fraction of the metal species in the catalyst is effective for the polymerisation. 

The possibility of changing the polymerisation mechanism depending on the kind of monomer as well as the catalyst, especially in binary or ternary comonomer systems, is obvious. This may also concern change in the nature of the growing species throughout the propagation of one polymer chain in the presence of both multinuclear catalysts [scheme (33)] and mononuclear catalysts [scheme (34)] ... 

Volume 26 of Annual Reports on NMR Spectroscopy serves to evince the fecundity of NMR in five distinct areas of scientific interest. These include food science, structural studies of peptides and polypeptides in the solid state by 15N NMR, high-resolution NMR as applied to polymer chemistry, the uses of cation NMR, in particular 87Rb, in studies on living systems, and finally, azo dyestuffs as studied by multinuclear NMR. 

H. Nishihara, Redox-based functionalities of multinuclear metal complex systems in A. S. Abd-El-Aziz and I. Manners (Eds.), Frontiers in Transition Metal-Containing Polymers, Wiley, Chichester, 2007. 

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