Cu2+ Selective Chromogenic Behavior of Calix[4]arene Derivative

This study involves the copper selective chromogenic response of 5, 11, 17, 23-Tetrakis (N-pyrrolidinomethyl)-25, 26, 27, 28-tetrahydroxycalix4]arene based mannich base (3). Complexation ability of (3) was explored by examining the effect of a series of various metal ions, such as Li⁺, Na⁺, K⁺, Ag⁺, Ba²⁺, Ca²⁺, Mn²⁺, Mg²⁺, Sr²⁺, Ni²⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Pb²⁺, Zn²⁺, Fe²⁺, Fe³⁺, and Al³⁺, by using UV-visible spectroscopy. Ligand (3) exhibited pronounced selectivity toward Cu²⁺ even in the presence of various co-existing ions. The stoichiometric analysis, i.e., Job's plot revealed that (3) form 1:1 complex with Cu²⁺ ion in DMF-H₂O system. The complexation phenomenon was confirmed by FT-IR spectroscopy that favors the selective nature of (3) with Cu²⁺.