The Synthesis and Characterization of Transition Metal Complexes of Mono Thiourea as Ligand and its Nonlinear Optic Application
DOI:
https://doi.org/10.11113/jomalisc.v3.81Keywords:
Thiourea, ligand, metal complexes, DFT, NLOAbstract
1,3-Diphenylthiourea (DPTU) is a promising candidate as a nonlinear optical (NLO) material due to its electronic structure, high dipole moment, and potential for strong nonlinear optical responses. It could be used in various photonic applications such as laser frequency conversion, optical switching, and signal processing. This study investigates the nonlinear optics (NLO) properties of metal complexes formed by using 1,3- diphenylthiourea as a ligand with different transition metals (copper, cadmium, and cobalt, labeled CA, CB, and CC respectively). Ligand was synthesized with a 70% yield. The characterization was performed using Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR), and Ultraviolet-Visible (UV-Vis) spectroscopy. Density Functional Theory (DFT) calculations with the 6-31G (d,p) basis set at the B3LYP level were used to optimize the structure of thiourea and compute the IR, 1H NMR, and UV-Vis spectra, which were then validated against experimental data. FT-IR analysis showed the C=S stretching peak at 1242.98 cm⁻¹ (experimental) and 1200.34 cm⁻¹ (computational) for the ligand. Upon complexation, the C=S stretching frequencies shifted to 1028.01 cm⁻¹ (CA), 1183.81 cm⁻¹ (CB), and 1205.50 cm⁻¹ (CC) experimentally, and to 1035.74 cm⁻¹ (CA), 1196.70 cm⁻¹ (CB), and 1221.18 cm⁻¹ (CC) computationally, with deviations under 5%. NMR analysis revealed amine peak signals at ẟ 9.633 ppm (H, NHa) and ẟ 8.169 ppm (H, NHb) for the ligand, shifting to ẟ 8.621 ppm (H, NHa) and ẟ 7.402 ppm (H, NHb) for CA. UV-Vis spectroscopy showed a π–π* transition for the ligand at 238 nm, shifting to 253 nm (CA), 266 nm (CB), and 265 nm (CC), with additional Metal-to-Ligand Charge Transfer (MLCT) transitions at 701 nm (CA), 429 nm (CB), and 507 nm (CC). DFT calculations indicated that the cobalt complex (CC) exhibits the highest NLO properties, with a frequency-dependent first hyperpolarizability (βtot) value of 6030.985 x10⁻³⁰ esu at 1064 nm, supported by a high dipole moment and low energy gap, making it the best candidate for NLO applications.
References
Mishra, A., Ninama, S., Sharma, P., Soni, N., & Awate, R. (2012). A newly synthesis and characterization of metal complexes of 3-(N-phenyl) thiourea-pentanone-2 as ligand. Journal of Physics: Conference Series, 365(1), Article 012039. https://doi.org/10.1088/1742-6596/365/1/012039
Daami, N., & Ali, R. (2015). Synthesis and characterization of 1-(4-chloro phenyl)-3-(pyrimidin-2-yl) thiourea and its complexes with cobalt(II), nickel(II), and copper(II). International Journal of Scientific and Engineering Research, 7(5), 87–93. https://www.iiste.org
Binzet, G., Kavak, G., Külcü, N., Özbey, S., Flörke, U., & Arslan, H. (2013). Synthesis and characterization of novel thiourea derivatives and their nickel and copper complexes. Journal of Chemistry, 2013, Article 536562. https://doi.org/10.1155/2013/536562
Raza, M. A., Javaid, K., Farwa, U., Javaid, A., Yaseen, M., Maurin, J. K., Budzianowski, A., Iqbal, B., & Ibrahim, S. (2023). One pot efficient synthesis of 1,3-di (naphthalen-1-yl) thiourea: X-ray structure, Hirshfeld surface analysis, density functional theory, molecular docking, and in-vitro biological assessment. Journal of Molecular Structure, 1271, Article 133989. https://doi.org/10.1016/j.molstruc.2022.133989
Sapari, S., Zakariah, E. I., Razak, N. H. A., Ramzan, I., Numin, M. S., Heng, L. Y., & Hasbullah, S. A. (2021). A comparative study of microwave-assisted and conventional heating methods for the synthesis of 1-(naphthalene-1-yl)-3-(o, m, p-tolyl)thioureas, DFT analysis, antibacterial evaluation, and drug-likeness assessment. Sains Malaysiana, 50(3), 743–751. https://doi.org/10.17576/jsm-2021-5003-16
Al-Halbosy, A. T. F., Hamada, A. A., Faihan, A. S., Saleh, A. M., Yousef, T. A., Abou-Krisha, M. M., Alhalafi, M. H., & Al-Janabi, A. S. M. (2023). Thiourea derivative metal complexes: Spectroscopic, anti-microbial evaluation, ADMET, toxicity, and molecular docking studies. Inorganics, 11(10), Article 390. https://doi.org/10.3390/inorganics11100390
Javadzade, T., Rzayeva, I., Demukhamedova, S., Akverdieva, G., Farzaliyev, V., Sujayev, A., & Chiragov, F. (2023). Synthesis, structural analysis, DFT study, antioxidant activity of metal complexes of N-substituted thiourea. Polyhedron, 231, Article 116274. https://doi.org/10.1016/j.poly.2022.116274
Noor, A., Qayyum, S., Ali, Z., & Muhammad, N. (2023). Syntheses and structural characterization of divalent metal complexes (Co, Ni, Pd, and Zn) of sterically hindered thiourea ligand and a theoretical insight into their interaction with SARS-CoV-2 enzyme. Journal of Molecular Structure, 1274(2), 42–54. https://doi.org/10.1016/j.molstruc.2022.134
Lewars, E. G. (2016). An outline of what computational chemistry is all about. In Computational chemistry (2nd ed., pp. 1–50). Springer. https://doi.org/10.1007/978-3-319-30685-6
Farooq, S., Hussain, A., Yar, M., Tariq, M., Mahmood, K., Ayub, K., Hussain, R., Rasool, F., Imran, M., & Assiri, M. A. (2023). Nonlinear optical response of facially polarized all cis-1,3,5-trifluorocyclohexane doped with transition metals and calcium. Journal of Molecular Liquids, 391, Article 123331. https://doi.org/10.1016/j.molliq.2023.123331
Canudo-Barreras, G., Ortego, L., Izaga, A., Marzo, I., Herrera, R. P., & Gimeno, M. C. (2021). Synthesis of new thiourea-metal complexes with promising anticancer properties. Molecules, 26(22), Article 6891. https://doi.org/10.3390/molecules26226891
