New fluorescent chemodosimeter for Cu²⁺ based on Schiff base derived from 1-naphthylamine and 2-chlorobenzaldehyde

Abstract

<span style="letter-spacing:-.2pt;mso-ansi-language: PT-BR" lang="PT-BR">On condensation of 1-naphthylamine with 2-chlorobenzaldehyde, the Schiff base (Z)-N-(2-chlorobenzylidene)naphthalene-1-amine (<b>L</b>) is formed which<span style="mso-ansi-language:PT-BR" lang="PT-BR"> shows moderate fluorescence. <b>L </b>on interaction with Cu²⁺ hydrolyses back into fluorescent 1-naphthylamine and hence acts as fluorescent chemodosimeter for Cu²⁺ by “off-on” mode with an <i>ca.</i> 18 times enhancement in fluorescent intensity (detection limit is 10^-5<i>M</i>). The other hydrolysed product, 2-chlorobenzaldehyde, forms a tris chelate complex with Cu²⁺, as shown by UV/visible spectroscopy and cyclic voltammetry. The metal ions, Na⁺, K⁺, Ca²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cd²⁺, Hg²⁺, Pb²⁺ and Ag⁺, do not interfere while in the case of Zn²⁺, moderate interference is observed.

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