Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

Abstract

Cu(II) complexes with Schiff bases derived from ethylenediamine (en) and 2-pyridinecarboxaldehyde (pyca), 2,5-dimethoxybenzaldehyde (dmbaH) or 4-imidazolecarboxaldehyde (4Him) were obtained and studied by elemental analysis, UV-VIS and IR spectra. Zinc oxide was synthesized using a simple homogeneous precipitation method with zinc acetate as a starting material. Thin layers of the studied Cu(II) complexes were deposited on Si(111) or ZnO/Si(111) substrates by a spin coating method and characterized with a scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectroscopy. For Cu(II) layers the most intensive fluorescence bands due to intra-ligand transitions were observed between 462 and 503 nm. The fluorescence intensity of thin layers was corelated to the rotation speed. In the case of the [Cu(II)(en(4Him) 2 )Cl 2 ](2a)/ZnO/Si and [Cu(en(dmbaH) 2 )Cl 2 ](3a)/ZnO/Si layers the quenching of the emission band from ZnO at 440 nm (λ ex = 330 nm) associated with various intrinsic or extrinsic lattice defects was noted.

Crystal structure, spectroscopic characterization and Hirshfeld surface analysis of aquadichlorido{N-[(pyridin-2-yl)methylidene]aniline}copper(II) monohydrate

“…Cu II ions coordinated by diimine N-donor ligands (-N C-C N-) are of great interest since they combine structural flexibility with other desired characteristics, such as ease of preparation, photophysical (Barwiolek et al, 2016) and photobiological (Banerjee et al, 2016) properties, and catalytic activity (Dias et al, 2010), as well as the capability to mimic active protein sites (Gupta & Sutar, 2008) and stabilize both metal oxidation states common in biological systems. These complexes also exhibit a broad spectrum of pharmacological properties including anti-inflammatory, antibacterial, antioxidant and antimetastatic (Chaviara et al, 2005) activities.…”

Synthesis of novel benzimidazoles and benzothiazoles via furan‐2‐carboxaldehydes, o‐phenylenediamines, and 2‐aminothiophenol using Cu(II) Schiff‐base@SiO2 as a nanocatalyst

“…Copper(II) complex of tetradentate Schiff‐base ligand immobilized onto silica [Cu(II) Schiff‐base@SiO 2 ] was produced by adding 3‐aminopropyl‐functionalized silica gel to copper(II) Schiff‐base complex in EtOH solvent at room temperature for 24 h. [ 75 ] Copper(II) Schiff‐base complex was prepared via the reaction of N , N ′‐bis‐(pyridin‐2‐ylmethylene)‐ethane‐1,2‐diamine in the presence of CuCl 2 .2H 2 O and EtOH at room temperature (Scheme 1). [ 83–87 ] The catalyst was characterized by FT‐IR, FESEM, energy‐dispersive X‐ray spectroscopy (EDX), XRD, and ICP.…”

“…The observed peaks at 1644 cm −1 represent the stretching band of imine (C═N) nitrogen groups of Schiff‐base (Figure 2a). [ 85 ] The shift of the (C═N) stretching band to around 1604 cm −1 suggests the coordination of ligand to the copper ion (Figure 2b). [ 85 ] The appearance of a peak in ~471 cm −1 is related to the formation of Cu–N during the immobilization of the Cu(II) Schiff‐base@SiO 2 (Figure 2c).…”

“…[ 85 ] The shift of the (C═N) stretching band to around 1604 cm −1 suggests the coordination of ligand to the copper ion (Figure 2b). [ 85 ] The appearance of a peak in ~471 cm −1 is related to the formation of Cu–N during the immobilization of the Cu(II) Schiff‐base@SiO 2 (Figure 2c). [ 85 ] The peaks at 797 and 1103 cm −1 are related to the symmetric and asymmetric stretching vibration of Si–O groups.…”

“…Copper(II) Schiff‐base complex was synthesized by N , N ′‐bis‐(pyridin‐2‐ylmethylene)‐ethane‐1,2‐diamine with CuCl 2 .2H 2 O (1.0 mmol) in ethanol solvent (10.0 mL) at room temperature for 4 h. After completion of the reaction, the thick precipitate was filtered off and washed with ethanol (3 × 5 mL) and obtained dark green solid copper(II) Schiff‐base complex. [ 83–87 ]…”