Manganese–calcium clusters supported by calixarenes

An investigation inspired by the structure of the oxygen-evolving complex of photosystem II has resulted in the isolation and structural characterization of the first examples of Mn/Ca clusters supported by a calixarene ligand.

Sensing hazardous metal ions using a fluoroionophore calix[4]arene species containing two 8-oxyquinoline groups

The interaction of a calix[4]arene-based species containing two 8-oxyquinoline chromophore pendants with hazardous metal ions has been investigated using optical absorption and fluorimetric techniques. In the presence of Hg2+, Cd2+, and Pb2+ ions, there is only a small decrease of the calixarene absorption band at 283 nm. The main changes are associated with the absorption band of the 8-oxyquinoline group at 315 nm, undergoing a systematic bathochromic shift to above 350 nm. In addition, a systematic decrease of the oxyquinoline emission at λem = 392 nm (λexc = 315 nm) has been observed. These observations are consistent with the coordination of the metal ions to the quinoline groups attached to the calixarene ligand, providing a useful fluoroinophore species for analytical purposes.