A highly selective quinaldine-indole based spiropyran with intramolecular H-bonding for visual detection of Cu(II) ions

A novel quinaldine-indole based spiropyran (QSP) with stabilized merocyanine form has been developed for colorimetric detection of Cu2+ ions. Chemosensor QSP shows high sensitivity and selectivity for Cu2+ ions amongst other metal ions (Na+, Mg2+, K+, Ca2+, Al3+, Co2+, Ni2+, Zn2+, Cd2+, Ba2+, La3+, Hg2+, Pb2+). The stoichiometry of QSP-Cu2+ complex determined by Jobs plot was found to be 1:1. The association constant for QSP-Cu2+ complex determine from Benesi-Hildbrand plot was 1.9 x 10(5) M-1 with a limit of detection 6.3 x 10(-7) M. Applicability of QSP to detect Cu2+ ions in tap water has been demonstrated, thus indicating the potential use of QSP as viable probe for visual detection of Cu2+ ions. (C) 2015 Elsevier B.V. All rights reserved.