Research Article Spectral, Structural, and Antibacterial Study of Copper(II) Complex with N 2 O 2 Donor Schiff Base Ligand and Its Usage in Preparation of CuO Nanoparticles Afshin Saadat , 1 Alireza Banaei, 2 Patrick Mcardle, 3 and Rana Jafari 2 1 Department of Chemistry, Germi Branch, Islamic Azad University, Germi, Iran 2 Department of Chemistry, Payame Noor University, Tehran, Iran P.O. Box 19395-4697 3 Department of Chemistry, NUI Galway, Galway, Ireland Correspondence should be addressed to Afshin Saadat; saadat@iaugermi.ac.ir Received 18 January 2022; Revised 23 February 2022; Accepted 11 March 2022; Published 30 March 2022 Academic Editor: Liviu Mitu Copyright © 2022 Afshin Saadat et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A new Schiff base complex, Cu(H 2 L) 2 (H 3 L: 6,6′ -((1E,1 ′ E)-((azanediylbis(ethane-2,1-diyl))bis(azanylylidene)) bis(methanylylidene))bis(2-methoxyphenol)), through the reaction of ligand H 3 L with Cu(NO 3 ) 2 3H 2 O, in the ratio of 2 : 1 in methanol solvent was prepared. The obtained ligand (H 3 L) was characterized by FT-IR, 13 C NMR, 1 H NMR and elemental analyses. Then its copper(II) complex was prepared and characterized by FT-IR spectroscopy, thermal studies, elemental analyses and single crystal X-ray diffraction. The X-ray crystallography revealed that the two H 3 L ligands in bidentate fashion coordinated to one copper center for producing Cu(H 2 L) 2 complex. We used copper(II) Schiff base complex, Cu(H 2 L) 2 , for the preparation of CuO nanoparticles via solid-state thermal decomposition. The crystalline structure of the product was studied by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). XRD indicated that the new product was copper oxide. SEM image showed that the size of CuO nanoparticles was between 46 and 53 nm, and they had uniform shape. The antibacterial properties of the complex and ligand were also investigated. The results revealed that Schiff base complex showed higher biological activity than Schiff base ligand. 1. Introduction Schiff base complexes have attracted many attentions in coor- dination chemistry because of their interesting applications, structures, and properties [1–4]. These complexes have been highlighted in coordination chemistry where they are used as catalysts for organic reactions and they also have interesting magnetic properties [5–7]. Moreover, metal complexes of Schiff bases received great importance in biology for their widespread applications [8, 9]. In biological systems, the Schiff bases characterized by an imine group (N=CH) help to explain the process of Schiff transamination and racemization reaction [10]. Tetradentate Schiff base ligands with a N 2 O 2 donor atom are popular for coordinating with different metal ions [11–13]. These Schiff base complexes have attracted more attentions since they can be used as antibacterial, antifungal, and antitu- mor agents [14–18]. Because of the applications of Schiff base complexes in the preparation of CuO nanoparticles, they have received considerable attention recently [19]. The synthesis and characterization of CuO nanoparticles through thermal decomposition of complexes have been widely studied because of their unique properties and applications. There are various methods for the preparation of CuO nanoparticles such as electrochemical, hydrothermal, and thermal decomposition and evaporation. Among them, thermal decomposition is a good choice because it can control process conditions and particle crystal structure, size, and purity [20–25]. Studies on thermal decomposition of metal complex for preparation of metal oxide nanoparticles indicated its superiority over other conventional methods since it is economical, rapid, and con- trollable [26, 27]. In the present study, we have synthesized 6,6 ′ -((1E,1 ′ E)-((azanediylbis(ethane-2,1diyl))bis(azanylylide- ne))bis(methanylylidene))bis(2-methoxyphenol) (H 3 L) Schiff base ligand and used it for the preparation of new Cu(H 2 L) 2 Hindawi Journal of Chemistry Volume 2022, Article ID 8913874, 13 pages https://doi.org/10.1155/2022/8913874