Selective recognition of Cu (II) and Fe (III) using a pyrene based chemosensor.

A pyrene-based colorimetric chemosensor 1-(pyren-1-yl)-N,N-bis-(pyridine-2-ylmethyl)methanamine (1) was synthesised for selective detection of Cu (II) and Fe (III) over the other metal cations Ni, Mg, Cd, Hg, Na, K, Ca, Co, Cr, Pb and Zn. The significant changes in UV-vis absorption band of receptor 1 and the emergence of 660nm band in presence of Cu ion indicates the selective binding of Cu ion as compared to other metal cations which could easily be identified from the naked eye strong colour change. Job plots suggest a 1:1 and 2:1 stoichiometric binding of Cu and Fe, respectively, which was evidenced by ESI-MS analysis. Chemosensor 1 explores a cost-effective and selective colorimetric sensor for naked eye detection of trace amount of Cu and Fe ions in presence of other metal cations.