Calixarenes as aryloxides: oligonuclear europium(iii) derivatives
Abstract
Synthetic and structural studies of europium complexes of calix[8]arene, p-t-Bu-calix[7]arene and p-t-Bu-calix[9]arene are reported. The complex [Eu2(calix[8]arene-6H)(dmso)5] was found to have a similar structure to previously reported p-t-Bu- and p-nitro-calix[8]arene complexes of the lanthanides. Despite being prepared under similar conditions, the complex of p-t-Bu-calix[7]arene was found to be a tetranuclear assembly, formulated as [(HO)2(OCO2)Eu4(p-t-Bu-calix[7]arene-4H)2(dmso)6]. Expanding the