The preparation of polymer-functionalized graphene nanoribbons (PF-GNRs) in a one-pot synthesis is described. Multiwalled carbon nanotubes (MWCNTs) were intercalated by potassium under vapor- or liquid-phase conditions, followed by the addition of vinyl or epoxide monomers, resulting in PF-GNRs. Scanning electron microscopy, thermogravimetric mass spectrometry, and X-ray photoelectron spectroscopy were used to characterize the PF-GNRs. Also explored here is the correlation between the splitting of MWCNTs, the intrinsic properties of the intercalants and the degree of defects and graphitization of the starting MWCNTs. The PF-GNRs could have applications in conductive composites, transparent electrodes, heat circuits, and supercapacitors.
COBISS.SI-ID: 36526597
This study investigates several CNT-supported Pd-based catalysts and compares their morphological as well as electrochemical characteristics for formic acid electro-oxidation. Pd/C catalysts were prepared via various impregnation methods, using different reaction media (EtOH, MeOH, THF, H2O) or reducing agents (hydroquinone or SDS). The average mean particle sizes of the precipitated Pd varied from 2.6 nm to 18.0 nm. It was further shown that the particle size of Pd/C dispersions can be easily controlled by changing the solvent and experimental conditions during the preparation procedure. Measurements of catalytic activity by using cyclic voltammetry revealed strong particle size dependence of the anodic peak current density. The electro-oxidation of formic acid may be kinetically-controlled or diffusion-controlled regarding the Pd morphological characteristics.
COBISS.SI-ID: 36573189
In addition to quinolones, which are O,O ligands, we have also decided to prepare ruthenium complexes of various ß-diketonates. Such ligands coordinate similarly as quinolones and it is known that their metal complexes exert interesting physico-chemical and biological properties. Five different fluorinated β-diketone ligands in the presence of sodium methoxide easily react with the organoruthenium precursor generating neutral complexes 1–5 with typical ‘‘piano-stool’’ geometry. All synthesized compounds were characterized by multinuclear NMR, X-ray diffraction and other standard physico-chemical methods. It was found that these compounds are ready-to-use catalysts, which are efficient for direct arylation of 2-phenylpyridine. Literature data revealed that frequently, compounds with catalytic properties exert also biological activity and we plan to test biological activity of isolated compounds in the future.
COBISS.SI-ID: 36426757
Nine novel and six previously reported zinc complexes with quinolones (oxolinic acid, enrofloxacin and flumequine) and bidentate nitrogen ligands (phananthroline and bipyridine) were synthesized and characterized by spectroscopic and analytical technique. A study of biological propetries of the zinc complexes and the free ligands was performed. All complexes exhibit good binding propensity to human or bovine serum albumin protein showing relatively high binding constant values. Interaction of the complexes with calf-thymus (CT) DNA, studied by UV spectroscopy, has shown that they bind to CT DNA. Competitive study with ethidiumbromide (EB) has shown that all complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. Intercalative binding mode is proposed for the interaction of the complexes with CT DNA and has also been verified by DNA solution viscosity measurements.
COBISS.SI-ID: 36469509
This work studied the phases in the Al corner of the Al-Mn-Be phase diagram inthe as-cast state and heat-treated conditions. Metallographic investigations, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy were used for identifying the phases. The Be contents in the identified phases were precisely determined using Auger electron spectroscopy. The results indicated that Al6Mn does not dissolve Be, whilst delta-Al4Mn dissolves up to 7 at.% Be. The average composition of the T phase, which is normally designated as Al15Mn3Be2, was 72 at.% Al, 19 at.% Mn, and 9 at.% Be. The phase with the nominal composition Be4AlMn contained more Al than Mn. The atomic ratio Al:Mn was between 1.3:1 and 2:1. The hexagonal Be-rich phase did not dissolve any Al and Mn. The icosahedral quasicrystalline (IQC) phase contained up to 45 at.% Be. The compositions of T phase, delta-Al4Mn, IQC, and Be4AlMn may vary, however, the ratio (Al + Be):Mn remained constant, and was close either to four or six indicating substitution of Al atoms with Be atoms in these phases.
COBISS.SI-ID: 16956694