Calixarenes copper complexes

Calixarenes, when in their cone-conformation (54), represent versatile host systems for metalated container molecules and many examples have been reported in the literature (55-61). Reinaud and coworkers have carried out extensive work concerned with calix[6]arenes that are functionalized at the small rim by nitrogen arms (62), aiming to reproduce the hydro-phobic binding site of mononuclear zinc and copper metalloen-zymes. A recent example is the calix[6]arene ligand L1 (Fig. 3), in which a tris(2-methylpyridyl)amine unit covalently caps the calixarene small rim (63). The ligand forms copper complexes of... 

In a study, Cacciapaglia et al. (2006) successfully synthesized a pseudo-biomimetic catalyst that worked as a phosphodiesterase enzyme [37]. For that purpose, 1,2-, 1,3-, and 1,2,3-positions of the upper rim of calix[4]arene were functionalized with 1,5,9-triazacyclododecane ([12]ane-N3) moieties, which were able to coordinate with several metals (see Fig. 27.15). These calix[4]arene derivatives were complexed with Zinc(II) and copper(II) to produce effective catalysts for the cleavage reaction of phosphodiester as RNA models. As seen in Fig. 27.16, the reaction takes place over the calixarene-metal complexes that indeed clarifies the importance of the substitution pattern of ligated metal ions (1,2-vicinal or 1,3-distal) along with cahx[4]arene skeleton. 

Key words Acidities, amino acids, binding mechanisms, calixarenes, choline, conformations, copper complexes, NMR, polyphenolates, resorcinarenes, supramolecular complexes. 

HPNPP (101) was also used to probe the catalytic ability of zinc- and copper-containing calix[4]arenes that carried two or three [12]ane-N3 macrocycles on their upper rim. Cooperativity was found between the catalytically active metal complexes during phosphodiester transesterification provided that they were adjacent to each other, i.e. on proximal positions of the calixarene rim, whereas those on opposite... 

Complexes consisting of functionalized calix[4]arenes with zinc (II) (Scheme 4.23), barium (II), copper (II), and lanthanum (III) were proved as most interesting and efficient catalytic systans [83-85]. In these studies, bi- and trinu-clear metal complexes consisting of Zn (II), Cu (II), and calixarene containing... 

---