Tuning of metal ion selectivity by varying number of coordinating atoms in quinoline-derived fluorescent sensors

การปรับความเลือกจำเพาะไอออนโลหะด้วยการปรับเปลี่ยนจำนวนอะตอมโคออร์ดิเนตในฟลูออเรสเซนต์เซ็นเซอร์จากควิโนลีน

Name: Jutawat Hojitsiriyanont

Abstract: Both Cd2+ and Zn2+ are metal ions in group 12 elements with very different toxicities but similar binding properties to most organic and biological ligands. In this work, a series of quinoline derivatives were synthesized and studied with an aim for Cd2+ selective turn-on fluorescent sensors. The structures of the compounds were designed to systematically evaluate the effects of amino protons, number of N-coordinating atoms, quinoline/picoline moieties and substituents on the sensing properties. The association constants of all synthesized ligands were studied by UV-vis absorption titration in aqueous solution. The results revealed that the ligands having 6- and 4- donor atoms and absent of amino proton gave higher association constants for Cd2+ and Zn2+, respectively. L6, a ligand with 2 quinolines/2 picolines and 6 N atoms without amino proton, exhibited the highest Cd2+ sensitivity providing 118-fold of fluorescence enhancement (I/I0) at 480 nm and highest Cd2+/Zn2+ selectivity giving the Cd2+/Zn2+ association constant ratio of 32. L5, a tetradentate ligand containing 1 quinoline/2 picolines without amino protons showed highest association constant for Zn2+. The greater number of the quinoline units led to lower binding affinity and lower I/I0. Fluorescence quenching was even observed for ligands having solely 3 and 4 quinoline units (L12 and L13). Electron withdrawing substituents gave higher I/I0 but lower association constants. L6 was thus selected for further optimization as Cd2+ fluorescent sensor. The selectivity of Cd2+ detection by L6 was significantly improved by an addition of tripicolylamine (TPA), a non-fluorescent tetradentate ligand, that provided the limit of detection Cd2+ of 69 nM. In the fluorescence cell imaging, L6 could monitor Cd2+ in the concentration range of 0.1–10 µM.

Chulalongkorn University. Office of Academic Resources

Address: BANGKOK

Email: cuir@car.chula.ac.th

Name: Mongkol Sukwattanasinitt

Role: advisor

Name: Vithaya Ruangpornvisuti

Role: advisor

Created: 2020

Modified: 2566-01-25

Issued: 2023-01-25

วิทยานิพนธ์/Thesis

application/pdf

URL: http://cuir.car.chula.ac.th/handle/123456789/76807

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Chemistry

Grantor: Chulalongkorn University

©copyrights Chulalongkorn University

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