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

Daniel J Fanna; Luís M P Lima; Alexander R Craze; Adrian Trinchi; Richard Wuhrer; Leonard F Lindoy; Gang Wei; Jason K Reynolds; Feng Li

doi:10.1021/acsomega.8b01483

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

ACS Omega. 2018 Sep 4;3(9):10471-10480. doi: 10.1021/acsomega.8b01483. eCollection 2018 Sep 30.

Authors

Daniel J Fanna^{1

2}, Luís M P Lima³, Alexander R Craze¹, Adrian Trinchi⁴, Richard Wuhrer⁵, Leonard F Lindoy⁶, Gang Wei², Jason K Reynolds¹, Feng Li¹

Affiliations

¹ School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751, Australia.
² CSIRO Manufacturing, P.O. Box 218, Lindfield, New South Wales 2070, Australia.
³ Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
⁴ CSIRO Manufacturing, Private Bag 33, Clayton, Victoria 3169, Australia.
⁵ Advanced Materials Characterisation Facility, Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751, Australia.
⁶ School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia.

Abstract

Herein, we report the synthesis and characterization of a chemosensor, 5-(diethylamino)-2-(2,3-dihydro-1H-perimidin-2-yl)phenol (HL), synthesized from a condensation between 4-(diethylamino)salicylaldehyde and 1,8-diaminonaphthalene. Upon investigation of the sensing properties of HL, it was found that this sensor may be employed for simple yet efficient detection of Cu²⁺ in aqueous methanol solutions. The selective and ratiometric response to Cu²⁺ 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 Cu²⁺ binding constants and complex speciation. Binding of Cu²⁺ to HL occurs in 1:1 stoichiometry, in good agreement with high-resolution electrospray ionization mass spectrometry (ESI-HRMS) results, Cu²⁺ titrations, and Job's plot experiments, while the coordination geometry was tentatively assigned as square pyramidal by spectroscopic studies.