Synthesis, Luminescent Properties, and Fluorimetric Detection of Nitroaromatic Explosives Using Novel Terbium(III) β-Diketone Complexes

International Journal of Chemistry | Vol. 8, No. 2, February 2017 | pp. 9–16

DOI: 10.46882/2017/IJC/000101

Article Type: Original Research Paper

Title: Synthesis, Luminescent Properties, and Fluorimetric Detection of Nitroaromatic Explosives Using Novel Terbium(III) β-Diketone Complexes

Names of Authors: A. O. Balogun¹, J. E. Kim²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Chemistry, Seoul National University, Seoul, South Korea.

Abstract: Rare-earth coordination materials displaying highly sensitive photoluminescent behaviors are increasingly sought for chemical sensor fabrications due to their sharp emission bands and high signal-to-noise ratios. This study reports the synthesis, material characterization, and analytical sensor optimization of a novel terbium(III) complex using 2-thenoyltrifluoroacetone and 1,10-phenanthroline ligands. Structural configurations were verified using elemental analysis, molar conductance, and Fourier-transform infrared (FT-IR) spectroscopy. Analytical calculations confirmed a 1:3:1 metal-to-ligand stoichiometric coordination pattern, conforming to the formula [Tb(TTA)₃(phen)]. Molar conductivity tests in acetonitrile confirmed a completely non-electrolytic layout. Photoluminescence scanning at room temperature showed intense green monochromatic emission peaks at 545 nm, corresponding to the characteristic ⁵D₄ to ⁷F₅ electronic transition of the central Tb(III) ion. The analytical potential of the complex as a fluorimetric sensor for trace nitroaromatic explosives was evaluated in aqueous media. The introduction of picric acid caused immediate, highly selective luminescence quenching of the green emission intensity. The fluorimetric quenching behavior followed the Stern-Volmer relationship with a high quenching constant (Ksv) of 4.5 x 10⁴ M⁻¹ and a low limit of detection (LOD) of 0.18 μM, pointing to a photoinduced electron transfer pathway.

Keywords: Terbium complexes; Rare earth elements; Photoluminescence; Fluorimetric sensor; Nitroaromatic explosives; Stern-Volmer relation

Manuscript Timeline: Received: May 12, 2016; Revised: June 25, 2016; Accepted: July 18, 2016; Published: February 04, 2017.

Citation: Balogun, A. O., & Kim, J. E. (2017). Synthesis, Luminescent Properties, and Fluorimetric Detection of Nitroaromatic Explosives Using Novel Terbium(III) β-Diketone Complexes. International Journal of Chemistry, 8(2), 9–16.

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