Ultrasensitive Colorimetric and Ratiometric Detection of Cu²⁺: Acid–Base Properties, Complexation, and Binding Studies

Abstract

Herein, we report the synthesis and characterization of a chemosensor, 5-(diethylamino)-2-(2,3-dihydro-1 H -perimidin-2-yl)phenol (H L ), synthesized from a condensation between 4-(diethylamino)salicylaldehyde and 1,8-diaminonaphthalene. Upon investigation of the sensing properties of H L , it was found that this sensor may be employed for simple yet efficient detection of Cu 2+ in aqueous methanol solutions. The selective and ratiometric response to Cu 2+ yielded an outstandingly low limit of detection of 3.7 nM by spectrophotometry and is also useful as a naked-eye sensor from 2.5 μM. The system was studied by spectrophotometric pH titrations to determine Cu 2+ binding constants and complex speciation. Binding of Cu 2+ to H L occurs in 1:1 stoichiometry, in good agreement with high-resolution electrospray ionization mass spectrometry (ESI-HRMS) results, Cu 2+ titrations, and Job’s plot experiments, while the coordination geometry was tentatively assigned as square pyramidal by spectroscopic studies.

A chromogenic diarylethene-based probe for the detection of Cu2+ in aqueous medium in Drosophila for early diagnosis of Alzheimer

“… 2-Naphthaldehyde based PBS buffer 1.0 × 10 −6 – – [ 47 ] 8. 1H-Perimidine based MeOH:H 2 O (1:1) 3.7 × 10 −9 EDTA real water samples [ 48 ] 9. Pyrene-based H 2 O 40 × 10 −9 – Bio-imaging in Bohonia Nigalandra and Monilia Albicans [ 49 ] 10.…”