Employing a hydrazine linked asymmetric double naphthalene hybrid for efficient naked eye detection of F-: Crystal structure with real application for F.

An asymmetric hydrazide, (12E, 13E)-2-((naphthalen-1-yl) methylene)-1-(1-(2-hydroxynaphthalen-6-yl) ethylidene) hydrazine (abbreviated as AH) is synthesized and characterized by standard techniques and crystal structure of AH has been obtained. The naked eye detection of F- in aqueous acetonitrile (acetonitrile: water=7:3/v:v) by AH has been investigated by UV-Visible titration and in presence of other anions, the limit of detection being 1.31×10-6(M). The mechanism of F- sensing has been explored by 1H NMR titration. AH undergoes hydrogen bonding with F- followed by deprotonation. The practical utility of AH has been explored by successful test kit response and color change in toothpaste solution.