ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Fluorescent detection of sodium diclofenac and tetracycline hydrochloride by a photoluminescent copper(I) thiocyanate-based complex

Simona Butan, Alexandra Virginia Bounegru, Sergiu Shova, and Aurel Tăbăcaru

Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, “Dunărea de Jos” University of Galati, Galati, Romania

E-mail: aurel.tabacaru@ugal.ro

Received: 21 February 2025  Accepted: 7 July 2025

Abstract:

The reaction of copper(I) thiocyanate (CuSCN) with triphenylphosphine (PPh₃) and 2,2’-dipyridylamine (dpa) in acetonitrile, at room temperature for just two hours, led to the formation of the photoluminescent complex [Cu(SCN)(PPh₃)(dpa)], which exhibits intense blue-green photoluminescence in the solid state. This synthesis route represents an advancement over previously reported method that required longer reaction time and different solvent, thus offering a more efficient and practical approach. Single-crystal X-ray diffraction revealed a novel crystal structure featuring a slightly distorted tetrahedral geometry around the Cu(I) center, stabilized by P, N, and S donor atoms from the ligands and thiocyanate. The resulting Cu(I) complex was applied to fluorescent detection studies and showed a strong affinity for the pharmaceutical analytes sodium diclofenac and tetracycline hydrochloride. This interaction was evidenced by significant fluorescence quenching, low limits of detection (LOD) of 3.14 µM for sodium diclofenac and 0.33 µM for tetracycline hydrochloride, and high binding constants (K_b) of 0.00714 µM⁻¹ and 0.00425 µM⁻¹, respectively. The complex exhibited a linear fluorescence response within relevant concentration ranges, suggesting excellent sensitivity and potential applicability for detecting trace pharmaceutical residues. These findings highlight the promise of this complex as a practical and efficient sensor, with implications for environmental monitoring and pharmaceutical quality control.

Keywords: Copper(I) complex; Photoluminescence; Fluorescent sensor; Sodium diclofenac; Tetracycline hydrochloride; Limit of detection

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04280-5

Chemical Papers 79 (11) 7689–7702 (2025)