Progress in appended calix[4]arene-based receptors for selective recognition of copper ions.

In the past two decades, there has been significant progress in the design and development of synthetic receptors for molecular recognition as they find application in the field of chemical, biological, medical, and environmental sciences. Synthetic receptors based on calix systems appended with fluorogenic and chromogenic groups have gained considerable attention for sensing and recognition of ions and molecules. Copper (Cu) is an essential element required in trace amounts in all living organisms to carry out various biological processes.