Phenol-formaldehyde macrocycles in polymer systems.
Part II. Preparation methods involving stepwise polyreactions
Polimery 2000, No 6, 381
SummaryA review with 29 references covering synthesis, properties and uses of polymers containing in-built phenol-formaldehyde macrocycles (calixarenes) with particular reference to the methods used to bond calixarenes to polymer chains. New methods are described to prepare multicalixarene oligomers endowed with dendritic and supramolecular struchzres. There are two principal routes to polymer systems including covalently linked calixarene units, viz., (i) to make a calixarene to react with a suitably functionalized polymer and (ii) to prepare a calixarene monomer and to polymerize or copolycondense it with commercial monomers. Route (ii) allows better-defined products to be prepared, because it eliminates the possibility of an incomplete reaction of functional groups of the polymer that in route (i) was used as a matrix. Calixarene monomers have been incorporated into polymer backbones by using functional groups within the narrow (Figs. 1 and 2) and the wide rim (Figs. 3 and 4). A drąwback to the route is that, when linked to the polymer chain, calixarene ionophores can distort the binding sites via interactions of the polymer backbone with macrocycle's receptor groups and thus result in reduced selectivity of complexation by the ionophore. In some cases conjugation of a calixarene with the polymer backbone can result in enhanced ionophore's activity, e.g., on account of the cumulated bonds formed in the polymer chain. Application of immobilized calixarenes in conducting polymers (Figs. 5 and 6) and to nonlinear optics (Figs. 5–7) is described. Other multicalixarene systems are also described (Figs. 9–13).