Dipicolylamine-Based Fluorescent Probes and Their Potential for the Quantification of Fe3+ in Aqueous Solutions

Nipuni N Vitharana; Chiranthi Kaushalya; Theshini Perera; Samitha P Deraniyagala; W M C Sameera; Asitha T Cooray

doi:10.1021/acsomega.2c02862

Dipicolylamine-Based Fluorescent Probes and Their Potential for the Quantification of Fe³⁺ in Aqueous Solutions

ACS Omega. 2022 Aug 1;7(32):28342-28350. doi: 10.1021/acsomega.2c02862. eCollection 2022 Aug 16.

Authors

Nipuni N Vitharana¹, Chiranthi Kaushalya¹, Theshini Perera¹, Samitha P Deraniyagala¹, W M C Sameera^{2

3}, Asitha T Cooray^{1

4}

Affiliations

¹ Department of Chemistry, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda 10250, Sri Lanka.
² Institute of Low Temperature Science, Hokkaido University, N19-W8, Kita-ku, Sapporo, Hokkaido 060-0819, Japan.
³ Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka.
⁴ Instrument Centre, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda 10250, Sri Lanka.

Abstract

We have synthesized two ligand systems, N(SO₂)(R₁)dpa (L1) and N(SO₂)(R₂)dpa (L2), where R₁ = biphenyl and R₂ = azobenzene, which are sulfonamide derivatives of the NNN-donor chelating dipicolylamine. Both L1 and L2 can be used as sensors for detecting Fe³⁺ and are highly sensitive and selective over a wide range of common cations. Time-dependent density functional theory (TDDFT) calculations confirmed that the key excitations of L2 and the [Fe(L2)(H₂O)₃]³⁺ model complex involve -R₂-unit-based π and π* charge transfer. L2 demonstrates a relatively high photostability, a fluorescence turn-on mechanism, and a detection limit of 0.018 μM with 1.00 μM L2 concentration, whereas L1 has a detection limit of 0.67 μM. Thus, both ligands have the potential to be used as fluorosensors for the detection of Fe³⁺ in aqueous solutions.