CALIXARENE AND RESORCINARENE LIGANDS IN TRANSITION-METAL CHEMISTRY

This is an exhaustive review of calixarenes containing transition meta ls. General preparative routes to calixarene ligands suitable for tran sition metal complexation are briefly reviewed. The aspects concerning their coordinative properties are organized according to the site and type of donor atom(s) involved in complexation. Emphasis has been pla ced on synthetic aspects so as to allow the reader to acquire a useful knowledge of the construction of transition metal complexes derived f rom calixarenes. Structural aspects have been systematically discussed for those complexes which have been characterized by X-ray analysis. Many interesting features of calixarene-derived ligands have been emph asized, e.g. the ability to act as bulky ligands or to behave as a pol yoxo surface and the possibility to form novel supramolecular assembli es and to associate a catalytic centre with a potential receptor cavit y. It is shown that transition metals are ideal partners for shaping o r assembling calixarenes, thus allowing the construction of a number o f large molecular systems, leading to various applications, notably li quid crystals, sensors for analytical purposes or molecular filters. ( C) 1997 Elsevier Science S.A.