Turn on fluorescence strip based sensor for recognition of Sr2+ and CN- via lowerrim substituted calix[4]arene and its

Fluorescence sensor L designed around a calix[4]arene scaffold, bearing two fluorogenic aminoquinoline moities, has been synthesized. It is found to be selective and sensitive towards Sr2+ and CN- over a wide range of cations and anions in a spectrofluorometric study in acetonitrile. The ion-binding property of L was monitored by fluorescence spectroscopy, UV-vis spectroscopy, ESI-MS, H-1 NMR, FT-IR investigation and PXRD study. The host L shows a minimum detection limit which is 1.36 nM for Sr2+ and 1.23 nM for CN- having concentration range 5-120 nM and 5-115 nM respectively. The calculated binding constants for L:Sr2+ and L: CN- are respectively 8.859 x 10(8) M-1 and 8.574 x 10(8) M-1. Our host L has been utilised in formation of a user-friendly, affordable, and disposable paper-based analytical device (PAD) for rapid chemical screening of Sr2+ and CN- ion via single strip. Moreover, the optimization of probe L has also been done by the MOPAC-2016 software package using NM7 popular method resulting -21.71 kcals/mol heat of formation and also determined the HOMO-LUMO energy band gap for L, L:Sr2+ and L: CN-. Further, molecular docking score has been calculated using HEX software. The applicability of our probe in real samples containing Sr2+ and CN- has also been checked by emission study with 94-99% recovery. (C) 2020 Elsevier B.V. All rights reserved.