We report the synthesis, characterization, crystal structures, nonlinear-optical (NLO) properties, and density functional theory (DFT) calculations of nickel(II) and copper(II) complex based ONO tridentate Schiff base ligands: two mononuclear compounds, [Ni(An-ONO)(NC₅H₅)] (5) and [Cu(An-ONO)(4-NC₅H₄C(CH₃)₃)] (6), and two heterobimetallic species, [M(Fc-ONO)(NC₅H₅)] (M = Ni, 7; Cu, 8), where An-ONOH₂ (3) and Fc-ONOH₂ (4) are the 1 : 1 condensation products of 2-aminophenol and p-anisoylacetone and ferrocenoylacetone, respectively. These compounds were characterised by microanalysis, FT-IR and X-ray crystallography in the solid state and in solution by UV-vis and ¹H and ¹³C NMR spectroscopy. The crystal structures of 3–5, 7 and 8 have been determined and show for Schiff base complexes 5, 7 and 8 a four-coordinated square-planar environment for nickel and copper ions. The electrochemical behavior of all derivatives 3–8 was investigated by cyclic voltammetry in dichloromethane, and discussed on the basis of DFT-computed electronic structures of the neutral and oxidized forms of the compounds. The second-order NLO responses of 3–8 have been determined by harmonic light scattering measurements using a 10⁻² M solution of dichloromethane and working with a 1.91 μm incident wavelength, giving rather high β_1.91 values of 350 and 290 × 10⁻³⁰ esu for the mononuclear species 5 and 6, respectively. The assignment and the nature of the electronic transitions observed in the UV-vis spectra were analyzed using time-dependent (TD) DFT calculations. They are dominated by LMCT, MLCT and π–π* transitions.

A new ferrocenyl-containing unsymmetrical Cu^II-Schiff-base complex, 2, and its covalently poly(methyl) (methacrylate) (PMMA)-grafted counterpart 3 were synthesized and characterized using elemental analysis, electrospray ionisation (ESI) mass spectrometry for 2, and FT-IR spectroscopy. New complex 3 was employed as a precatalyst in the copper-catalyzed [3+2] cycloaddition of organic azides to alkynes (CuAAC, “click” reaction). The active Cu^I species generated from only 0.2 mol% of Cu^II precatalyst 2 and sodium ascorbate displayed high activity at room temperature in ethanol for 24 hours allowing the synthesis of a wide variety of 1,4-disubstituted 1,2,3-triazoles in high isolated yields. The PMMA-supported catalyst 3 is also efficient and has been reused at least three times in these “click” reactions without any loss of activity or copper leaching.

Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200–5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.