Synthesis and coordination chemistry of lower rim cavitand ligands

Four new cavitand ligands, modified at the lower rim with cyano and pyridyl functional groups, have been synthesized and their coordinative behaviour toward transition metal ions has been explored. The outcome of the self-assembly of these compounds in the presence of different metal precursors is biased toward the formation of intramolecular complexes, independent of the coordination geometry imposed by the metal centre. Dimeric species have been obtained by decreasing the number of ligands at the lower rim from four to two and by using a metal precursor capable of exchanging four ligands simultaneously.