A novel and selective sorbent for micro-solid phase extraction was synthesized by chemical functionalization of graphene oxide with glycine. The structure of this nanomaterial, referred to as GO-Gly, was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. GO-Gly was used for preconcentration of chromium, zinc, and copper ions from water samples prior to their determination by energy dispersive X-ray fluorescence spectrometry (EDXRF). The proposed procedure is based on dispersion of micro amounts of GO-Gly in aqueous samples. After adsorption of metal ions on its surface, samples were filtered under vacuum and then membrane filters were directly submitted to energy dispersive X-ray fluorescence spectrometric measurements. In order to obtain optimal preconcentration conditions, some parameters affecting sorption process, such as pH, amount of GO-Gly, sorption times, and sample volume, were examined. Under optimal conditions the calibration curves were linear in a 1–150 ng mL⁻¹ range with recoveries higher than 97%. The obtained detection limits for Cr(III), Zn(II), and Cu(II) determinations are 0.15, 0.07, and 0.08 ng mL⁻¹, respectively. A relative standard deviation of the proposed procedure (at a 10 ng mL⁻¹ level for n = 10) is lower than 2.3%. The proposed method was successfully applied for determination of Cr(III), Zn(II), and Cu(II) ions in water samples.

Three Re(I) carbonyl complexes [ReCl(CO)₃(Lⁿ)] bearing 2,2′-bipyridine, 2,2′:6′,2′′-terpyridine, and 1,10-phenanthroline functionalized with diphenylamine/or triphenylamine units (L¹–L³) were synthesized to explore the impact of highly electron donating units appended to the imine ligand on the thermal and optoelectronic properties of Re(I) systems. Additionally, for comparison, the ligands L^1–3 and parent complexes [ReCl(CO)₃(bipy)], [ReCl(CO)₃(phen)] and [ReCl(CO)₃(terpy-κ²N)] were investigated. The thermal stability was evaluated by differential scanning calorimetry. The ground- and excited-state electronic properties of the Re(I) complexes were studied by cyclic voltammetry and differential pulse voltammetry, absorption and emission spectroscopy, as well as using density-functional theory (DFT). The majority of the compounds form amorphous molecular materials with high glass transition temperatures above 100 °C. Compared to the unsubstituted complexes [ReCl(CO)₃(bipy)], [ReCl(CO)₃(phen)] and [ReCl(CO)₃(terpy-κ²N)], the HOMO–LUMO gap of the corresponding Re(I) systems bearing modified imine ligands is reduced, and the decrease in the value of the ΔE_H–L is mainly caused by the increase in HOMO energy level. In relation to the parent complexes, all designed Re(I) carbonyls were found to show enhanced photoluminescence, both in solution and in solid state. The investigated ligands and complexes were also preliminarily tested as luminophores in light emitting diodes with the structures ITO/PEDOT:PSS/compound/Al and ITO/PEDOT:PSS/PVK:PBD:compound/Al. The pronounced effect of the ligand chemical structure on electroluminescence ability was clearly visible.