Naphthoquinone based chemosensor 2-(2′-aminomethylpyridine)-3-chloro-1,4-naphthoquinone for metal ions: Single crystal X-ray structure, experimental and TD-DFT study

Naphthoquinone based redox active chemosensor 1; 2-(2'-aminomethylpyridine)-3-chloro-1,4-naphthoquinone ligand has been synthesized and characterized. Chemosensor 1 crystallizes in monoclinic space group P2(1)/n. Molecules showed intramolecular N-H center dot center dot center dot O and N-H center dot center dot center dot N, intermolecular N-H center dot center dot center dot O, C-H center dot center dot center dot O and slipped pi-pi stacking interactions. Chemosensor 1 showed orange colored solution in methanol and specifically detects Cu2+ ions by deprotonation of N-H. The deprotonation of amino N-H can also be achieved by mild base viz. triethylamine and chemosensor 1 can be used to detect several metal ions for example Ni2+, Mn2+ etc. that could observed by naked eye. Color changes observed were monitored by UV-visible and fluorescence spectra. Chemosensor 1 could provide either bidentate or tridentate coordination sites to metal ions. Redox nature of chemosensor 1 was evaluated by cyclic voltammetry studies. Electronic transition wavelengths of chemosensor 1 ligand have been evaluated in methanol, water and triethylamine by TD-DFT studies and comparative studies were performed with experimental results. (C) 2015 Elsevier B.V. All rights reserved.