A simple benzimidazole styryl-based colorimetric chemosensor for dual sensing application

A new colorimetric styryl-benzimidazole based receptor to recognize more than one analyte trans-2-[4'-(dimethylamino) styryl] benzimidazole) (L1) has been synthesized and fully characterized by C-13 and H-1 NMR, elemental analysis, UV-vis spectroscopy, and HRMS. Investigation of sensing ability of receptor L1was carried out in presence ofmultiple anions (Br-, CN-, Cl-, ClO4-, F-, HSO4-, PF6-, NO3-, S-2(-), OH-, AcO- and H2PO4-) and cations (Cu2+, Cr3+, Al3+, Mg2+, Cd2+, Ni2+, Fe3+, K+, Fe2+, Mn2+, Ag+, Hg2+, Ca2+, Co2+, Pb2+, Na+, and Zn2+) by using UV-vis spectroscopy. Receptor L1 showed colorimetric response towards only for HSO4- ion. Receptor L1-HSO4- interaction confirmed with the help of H-1 NMR titration. Among various cations, L1 selectively sense the Cu2+ and Al3+ with the drastic colour change from yellow to green and dark yellow respectively. The stoichiometric binding ratio of L1 with HSO4-, Cu2+, and Al3+ found to be 1: 1 by jobs method and HRMS data proved the complex formation between L1 and Cu2+/Al3+ with very low detection limit. In addition to explore practical applicability of L1, paper strips have been made and used to detect HSO4- and Cu2+ ions, respectively, up to 10 ppm level. (C) 2019 Elsevier B.V. All rights reserved.