Marek Matussek

Glycine modified graphene oxide as a novel sorbent for preconcentration of chromium, copper, and zinc ions from water samples prior to energy dispersive X-ray fluorescence spectrometric determination

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.

NCN-Coordinating Ligands based on Pyrene Structure with Potential Application in Organic Electronics

Five novel derivatives of pyrene, substituted at positions 1,3,6,8 with 4-(2,2-dimethylpropyloxy)pyridine (P1), 4-decyloxypyridine (P2), 4-pentylpyridine (P3), 1-decyl-1,2,3-triazole (P4), and 1-benzyl-1,2,3-triazole (P5), are obtained through a Suzuki-Miyaura cross-coupling reaction or CuI -catalyzed 1,3-dipolar cycloaddition reaction, respectively, and characterized thoroughly. TGA measurements reveal the high thermal stability of the compounds. Pyrene derivatives P1-P5 all show photoluminescence (PL) quantum yields (Φ) of approximately 75 % in solution. Solid-state photo- and electroluminescence characteristics of selected compounds as organic light-emitting diodes are tested. In the guest-host configuration, two matrixes, that is, poly(N-vinylcarbazole) (PVK) and a binary matrix consisting of PVK and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) (50:50 wt %), are applied. The diodes show red, green, or blue electroluminescence, depending on both the compound chemical structure and the actual device architecture. In addition, theoretical studies (DFT and TD-DFT) provide a deeper understanding of the experimental results.

Luminescent-Substituted Fluoranthenes-Synthesis, Structure, Electrochemistry, and Optical Properties

Six novel fluoranthene derivatives, namely, three terminally substituted and three bis(fluoranthene) units with fluorene, bithiophene, and carbazole spacers, were obtained through [2+2+2] cycloaddition and characterized completely. Based on the conducted studies, the obtained derivatives can be classified as donor-acceptor (D-A) and acceptor-donor-acceptor (A-D-A) systems, in which the fluoranthene unit acts as an electron-withdrawing unit. The optical results revealed that novel fluoranthene derivatives absorb light in the range λ=236-417 nm, which originates from a π→π* transition within the conjugated system. The compounds exhibit fluorescence that range from deep blue to green, which mainly arises from intramolecular charge transfer (ICT) states. High Stoke shifts and high quantum yields in solution (ϕ=0.22-0.57) and in the solid state (ϕ=0.18-0.44) have been observed for fluoranthene derivatives. All the derivatives display multistep oxidation processes at low potentials. The electronic structure of the presented compounds is additionally supported by time-dependent DFT computations.