A fluorescent copper(II) complex based on 4,4-oxybisbenzoic acid and benzimidazole for selective detection of nitroaromatic compounds

Victoria T. Olayemi; Adetola C. Oladipo; Vincent O. Adimula; Ayobami C. David; John O. Abedoh; Basheer A. Jaji; Adedibu C. Tella

doi:10.46481/jnsps.2026.3130

Authors

Victoria T. Olayemi
[email protected]

Department of Chemistry and Industrial Chemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B 1530, Malete, Nigeria
Adetola C. Oladipo
Department of Physical Sciences, Landmark University, Omu-Aran, Kwara State, Nigeria.
Vincent O. Adimula
Department of Chemistry, University of Ilorin, P.M. B 1515, Ilorin, Kwara State, Nigeria.
Ayobami C. David
Department of Chemistry and Industrial Chemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B 1530, Malete, Nigeria
John O. Abedoh
Department of Chemistry and Industrial Chemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B 1530, Malete, Nigeria
Basheer A. Jaji
Department of Chemistry and Industrial Chemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B 1530, Malete, Nigeria

Department of Physical \& Chemical Sciences, Faculty of Sciences, Federal University of Health Sciences Ila-Orangun, Nigeria.
Adedibu C. Tella
Department of Chemistry, University of Ilorin, P.M. B 1515, Ilorin, Kwara State, Nigeria.

Keywords:

Emission, Ligand, Nitroaromatics, Spectroscopy, Quenching

Abstract

Nitroaromatic compounds (NACs) are electron-deficient aromatic molecules extensively used in explosives, dyes, and pesticides, and their high toxicity and environmental persistence pose serious risks to human health and ecological systems. Consequently, the development of sensitive, selective, and portable sensing platforms for NAC detection is of significant importance. In this work, a copper-based coordination complex, [Cu(Oba)₂(Beim)(H₂O)] (1) (H2Oba = 4,4’-oxybisbenzoic acid; Beim = benzimidazole), was synthesized via a conventional method and fully characterized using standard instrumental techniques. Infrared spectroscopy confirmed the coordination environment, with characteristic bands observed at 1666 cm^-¹(vC = O), 1243 cm^-¹(vC - - N), and 3061 cm^-¹(vN --H). The complex exhibits strong fluorescence emission at 490 nm and good thermal stability. Fluorescence sensing studies revealed a significant quenching response in the presence of NACs, particularly 4-nitroaniline. The sensor demonstrated a low limit of detection (LOD) of 1.46 ppm and a high Stern–Volmer quenching constant (KSV = 9.16 × 10⁴M^-¹) towards 4-nitroaniline, indicating excellent sensitivity and selectivity. Furthermore, recyclability experiments showed that the complex could be reused for up to four sensing cycles without significant loss of performance. These results highlight the potential of the copper coordination complex as an efficient and reusable fluorescent sensor for nitroaromatic compounds.

Dimensions

REFERENCES

[1] J. Tiwari, P. Tarale, S. Sivanesan, & A. Bafana, “Environmental persistence, hazard, and mitigation challenges of nitroaromatic compounds”, Environ. Sci. Pollut. Res. 26 (2019) 28650. https://doi.org/10.1007/s11356-019-06043-8.

[2] D. Zhao,S. Yu, W. Jiang ,Z. Cai,D. Li,Y. Liu & Z. Chen, “Recent progress in metal-organic framework based fluorescent sensors for hazardous materials detection”, Molecules 27 (2022) 1. https://doi.org/10.3390/molecules27072226.

[3] A. Chatz-Giachia, A. E. Psalti, A. D. Pournara,M. J. Manos, C. Pappa, K. Triantafyllidis & T. Lazarides, “Detection of nitrophenols with a fluorescent Zr(IV) metal-organic framework functionalized with benzylamino groups”, J. Mater. Chem. C 34 (2022) 12307. https://doi.org/10.1039/d2tc02494b.

[4] M. J. Tsai, C. Y. Li, & J. Y. Wu, “Luminescent Zn(II) coordination polymers as efficient fluorescent sensors for highly sensitive detection of explosive nitroaromatics”, Crys. Eng. Comm. 20 (2018) 6762. https://doi.org/10.1039/c8ce01371c.

[5] J. Yan, J. C. Ni, J. X. Zhao, L. X. Sun, F. Y. Bai, Z. Shi & Y. H. Xing, “The nitro aromatic compounds detection by triazole carboxylic acid and its complex with the fluorescent property”, Tetrahedron 73 (2017) 2682. https://doi.org/10.1016/j.tet.2017.03.057.

[6] B. Dutta, S. Paul, & S. Halder, “Explosive and pollutant nitroaromatic sensing through a Cd(II) based ladder shaped 1D coordination polymer”, Heliyon 9 (2023) e13504. https://doi.org/10.1016/j.heliyon.2023.e13504.

[7] A. C. Tella, V. T. Olayemi, F. A. Adekola, A. C. Oladipo, V. O. Adimula, J. O. Ogar, E. C. Hosten, A. S. Ogunlaja, S. P. Argent & R. Mokaya , “Synthesis, characterization and density functional theory of copper(II) complex and cobalt(II) coordination polymer for detection of nitroaromatic explosives”, Inorganica Chim. Acta 515 (2021) 120048. https://doi.org/10.1016/j.ica.2020.120048.

[8] L. Lu,J. Wang, W. Wu, A. Ma, J. Liu , R. Yadav & A. Kumar, “Fluorescent sensing of nitroaromatics by two coordination polymers having potential active sites”, J. Lumin. 186 (2017) 40. https://doi.org/10.1016/j.jlumin.2017.02.010.

[9] W. D. Li, S. S. Chen, S. S. Han, & Y. Zhao, “The syntheses, structures, and properties of metal-organic frameworks based on mixed multi-N donor and carboxylate ligands”, J. Solid State Chem. 283 (2020) 121133. https://doi.org/10.1016/j.jssc.2019.121133.

[10] A. A. Alhadi, S. A. Shaker, W. A. Yehye, H. M. Ali, & M. A. Abdullah, “Synthesis, magnetic and spectroscopic studies of Ni(II), Cu(II), Zn(II) and Cd(II) complexes of a newly Schiff base derived from 5-bromo-2-hydroxybezylidene)-3,4,5-trihydroxybenzohydrazide)”, Bull. Chem. Soc.Ethiop. 26 (2012) 95. https://doi.org/10.4314/bcse.v26i1.10.

[11] V. P. Singh, K. Tiwari, & M. Mishra, “Synthesis, spectral and thermal studies of some polymeric mixed ligand uracil-hydrazide complexes with transition metal ions”, Des. Monomers Polym. 16 (2013) 456. https://doi.org/10.1080/15685551.2012.747164.

[12] T. Aiyelabola, E. Akinkunmi, E. Obuotor, I. Olawuni, D. Isabirye, & J. Jordaan, “Synthesis characterization and biological activities of coordination compounds of 4-hydroxy-3-nitro-2 h-chromen-2-one and its aminoethanoic acid and pyrrolidine-2-carboxylic acid mixed ligand complexes”, Bioinorg. Chem. Appl. 2017 (2017) 6426747. https://doi.org/10.1155/2017/6426747.

[13] K. J. Vetti & A. Koca, “Highly efficient iron and cobalt benzimidazole metal organic framework electrocatalysts for hydrogen evolution reaction”, Int. J. Hydrogen Energy 97 (2025) 214. https://doi.org/10.1016/j.ijhydene.2024.11.421.

[14] E. R. Souaya, W. G. Hanna, E. H. Ismail, & N. E. Milad, “Studies on some acid divalent-metal nitrilotriacetate complexes”, Molecules 5 (2000) 1121. https://doi.org/10.3390/51001121.

[15] P. M. Thabede, N. D. Shooto, & S. J. Modise, “Synthesis of lanthanum metal organic framework using 1,4 benzenedicarboxylic acid”, Dig. J. Nanomater. Biostructures 18 (2023) 157. https://doi.org/10.15251/DJNB.2023.181.157.

[16] M. M. Abou, T. I. Kashar, & S. A. Aly, “Author ’ s personal copy Spectrochemical study and effect of high energatic gamma ray on copper (II) complexes”, Solid State Sciences 13 (2011) 2080. https://doi.org/10.1016/j.solidstatesciences.2011.07.015.

[17] S. Elmehrath, K. Ahsan, N. Munawar, A. Alzamly, H. L. Nguyen, & Y. Greish, “Antibacterial efficacy of copper-based metal-organic frameworks against Escherichia coli and Lactobacillus”, RSC Adv. 14 (2024) 15821. https://doi.org/10.1039/d4ra01241k.

[18] Z. Tang, H. Chen, Y. Zhang, B. Zheng, S. Zhang, & P. Cheng, “Functional two-dimensional coordination polymer exhibiting luminescence detection of nitroaromatics”, Cryst. Growth Des. 19 (2019) 1172. https://doi.org/10.1021/acs.cgd.8b01640.

[19] M. Kou, X. Zhai, W. long Duan, P. Zhang, J. Mart´ı-Rujas, & F. Guo, “Exploring the sensing behavior in the detection of nitroaromatics using coordination complexes based on 4,4’-(1,3-phenylenedioxy)-dianiline ligand”, Inorganica Chim. Acta 494 (2019) 154. https://doi.org/10.1016/j.ica.2019.05.012.

[20] M. M. Chen, X. Zhou, H. X. Li, X. X. Yang, & J. P. Lang, “Luminescent two-dimensional coordination polymer for selective and recyclable sensing of nitroaromatic compounds with high sensitivity in water”, Cryst.Growth Des. 15 (2015) 2753. https://doi.org/10.1021/acs.cgd.5b00095.

[21] G. Chakraborty, P. Das, & S. K. Mandal, “Strategic construction of highly stable metal-organic frameworks combining both semi-rigid tetrapodal and rigid ditopic linkers: selective and ultrafast sensing of 4-nitroaniline in water”, ACS Appl. Mater. Interfaces 10 (2018) 42406. https://doi.org/10.1021/acsami.8b15894.

[22] M. Bagheri, M. Y. Masoomi, & A. Morsali, “Highly sensitive and selective ratiometric fluorescent metal–organic framework sensor to nitroaniline in presence of nitroaromatic compounds and VOCs”, Sensors Actuators, B Chem. 243 (2017) 353. https://doi.org/10.1016/j.snb.2016.11.144.