Architecture of dipodal ratiometric motif showing discrete nanomolar response towards fluoride ion

A new fluoride selective fluorescent receptor (13E,19E)-N1',N3'-bis[4-(diethylamino)-2-hydroxybenzylidene]malonohydrazide (1) was designed and synthesized. Receptor 1 showed a highly selective fluorescent 'turn-on' response towards F- among the various tested anions such as F-, Cl-, Br-, I-, HSO4-, (HPO4-)-P-2, NO2- and CN- in CH3OH:H2O (50:50, v/v), due to the formation of hydrogen bonding host-guest complex in 1:1 stoichiometry with a detection limit of 45.7 nM and association constant of 1.0 x 10(4)M(-1). The nature of interactions between the receptor 1 and F- was investigated by H-1 NMR and the probable structure of the 1.F- complex was predicted by B3LYP/6-31G(**) method. (C) 2014 Elsevier B.V. All rights reserved.