Synthesis, Time-Resolved Photoluminescence, and Trace Explosive Sensing of Novel Samarium(III) Complex Networks

International Journal of Chemistry | Vol. 11, No. 7, July 2020 | pp. 49–56

DOI: 10.46882/2020/IJC/000141

Article Type: Original Research Paper

Title: Synthesis, Time-Resolved Photoluminescence, and Trace Explosive Sensing of Novel Samarium(III) Complex Networks

Names of Authors: A. O. Balogun¹, Y. K. Tanaka²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo, Japan.

Abstract: Sm(III) coordination networks display specific orange-red luminescence tracks that serve as sensitive signaling systems for modern chemical detection platforms. This study details the chemical synthesis, structural characterization, and analytical sensing validation of a novel samarium(III) complex built with acetylacetone and 2,2'-bipyridine. The elemental compositions, crystal geometries, and binding architectures were resolved using elemental microanalysis, molar conductivity, and Fourier-transform infrared (FT-IR) spectroscopy. Quantitative data confirmed a 1:3:1 metal-to-ligand stoichiometry with an empirical formula of [Sm(acac)₃(bipy)]. Conductance profiles in acetonitrile established a non-electrolytic layout. Room-temperature photoluminescence scans showed narrow, characteristic emission peaks at 563 nm, 598 nm, and 642 nm, corresponding to the ⁴G₅/₂ to ⁶H_J (J = 5/2, 7/2, 9/2) transitions of the Sm(III) core. The operational utility of the complex as a fluorimetric sensor for trace nitroaromatic chemical explosives was tested systematically in aqueous systems. The introduction of 2,4-dinitrotoluene triggered an immediate, concentration-dependent quenching of the orange emission intensity. The fluorimetric quenching curve conformed tightly to the Stern-Volmer relationship, showing a high quenching constant (Ksv) of 3.4 x 10⁴ M⁻¹ and a low limit of detection (LOD) of 0.24 μM, driven by an intermolecular photoinduced electron transfer path.

Keywords: Samarium complexes; Rare earth elements; Photoluminescence; Fluorimetric sensor; Nitroaromatic explosives; Stern-Volmer equation

Manuscript Timeline: Received: January 14, 2020; Revised: March 02, 2020; Accepted: April 12, 2020; Published: July 04, 2020.

Citation: Balogun, A. O., & Tanaka, Y. K. (2020). Synthesis, Time-Resolved Photoluminescence, and Trace Explosive Sensing of Novel Samarium(III) Complex Networks. International Journal of Chemistry, 11(7), 49–56.

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