Development of sensitive and selective chemosensors for trace detection of metals (e.g. copper(II), lead(II) and mercury(II) ions) rich in nature, either associated to important physiological processes or representing environmental hazards and health issues is an attractive area of current research.

Calixarenes are one of the most widespread scaffolds in host-guest chemistry because of their rigid structures, which make them perfect candidates for complexation studies with ions and neutral molecules through the formation of inclusion complexes.

In this communication we report the chemosensing ability of newly designed bicyclic calix[4]arene-carbazole-polymers (Calix-OCP-PPE-CBZs) and a sole molecular probe (Calix-OCP-2-CBZ) toward metal ions in fluid phase. Evidence for the formation of a ground-state complex between Calix-OCP-PPE-2,7-CBZ and Cu(II) came from UV-Vis spectroscopic titrations.

Two clear isosbestic points appear at 370 and 439 nm indicating the establishment of the binding equilibrium of Cu(II) with Calix-OCP system which was supported by the high binding energy(DE = -1616.6 kJ/mol) obtained by DFT calculations for a model compound with Cu(II), confirming the ligand-to metal charge transfer (LMCT) bands observed in UV-Vis titrations and thus the formation of supramolecular inclusion complexes.