Pure and binary adsorption of CO2, H2, and N2 on activated carbon

A new developing field of application for pressure swing adsorption (PSA) processes is the capture of CO₂ to mitigate climate change, especially the separation of CO₂ and H₂ in a pre-combustion context. In this process scheme the conditions of the feed to the separation step, namely a pressure of 3.5 to 4.5 MPa and a CO₂ fraction of around 40% are favorable for an adsorption based separation process and make PSA a promising technology. Among the commercial adsorbent materials, activated carbon is most suitable for this application. To evaluate the potential, to benchmark new materials, and for process development a sound basis of the activated carbon thermodynamic data is required, namely equilibrium adsorption isotherms of the relevant pure components and mixtures, Henry’s constants and isosteric heats.     

Synthesis of a [2.2]paracyclophane based planar chiral palladacycle by a highly selective kinetic resolution/C-H activation reaction

Kinetic resolution of racemic 4-N,N-dimethylaminomethyl[2.2]paracyclophane with 50% sodium tetrachloropalladate and (R)-N-acetylphenylalanine under basic conditions resulted in the formation of a (S(p))-planar chiral palladacycle (35%, >99% ee). Similarly use of 100 mol% sodium tetrachloropalladate resulted in higher levels of conversion and recovery of (S(p))-4-N,N-dimethylaminomethyl[2.2]paracyclophane (41%, >97% ee).     

Synthesis of stable free base secochlorins and their corresponding metal complexes from meso-tetraarylporphyrin derivatives

Cleavage reactions of 2,3-diamino-meso-tetraarylporphyrins and meso-tetraarylporphyrins fused to imidazole rings afforded secochlorins including stable free base derivatives.     

Ruthenium(II) complexes with new large-surface ligands based on electron-accepting expanded pyridiniums: insights from density functional theory

With the aim of designing new inorganic photosensitizers for photovoltaic applications, the structural and electronic properties of two Ru(II) complexes containing terpyridine-based ligands derived from expanded pyridiniums both branched—polyphenyl—and fused—polycyclic—were investigated by the means of density functional theory (DFT) and time-dependent DFT (TD-DFT). In particular, the structure and electronic absorption of the fused architectures—including the isolated ligand and its complex—were compared with those of their respective branched precursors with the aim to account for the their enhanced electronic features in the visible spectral region. The theoretical insights gained into the “large-surface” ligand and its associated complex open the route for a joint experimental and theoretical design of new inorganic photosensitizers based on fused expanded pyridiniums.     

Tripodal europium complex with triangulenium dye: a model bifunctional metallo-organic system

A new tripodal ligand has been designed by coupling pyridyldicarbonyl binding strands with a triazatriangulenium platform (TATA). The complexation reaction with europium provides a C(3)-symmetrical mononuclear compound that is characterized with NMR, ESMS and qualitatively with single-crystal X-ray crystallography. In addition, photophysical studies of this dual emissive system have been performed, since the combination of the TATA fluorophore with trivalent lanthanides is of potential interest for the further development of imaging applications.     

Glyphosate and ATP binding by mononuclear Zn(ii) complexes with non-symmetric ditopic polyamine ligands

Binding of Zn(ii) by the ditopic ligands L1py, L2py and L1para, composed of a cyclam unit linked to the linear polyamines 1,4,8,11-tetraazaundecane (L1py and L2para) and 1,4,7-triazaheptane (L2py) via a 2,6-dimethylpyridinyl (L1py and L2py) or a 1,4-dimethylbenzyl spacer (L2para), has been analyzed by means of potentiometric and (1)H and (13)C NMR measurements. All ligands form stable mononuclear Zn(ii) complexes in a wide pH range, featuring the metal ion bound to the macrocyclic unit. The open-chain polyamine unit can easily bind several protons in aqueous solution affording protonated metal complexes at neutral and acidic pH values. These complexes behave as bifunctional receptors for the anionic substrates N-(phosphonomethyl)glycine (glyphosate or PMG) and ATP. Potentiometric, (1)H and (31)P NMR measurements show that the Zn(ii) complex with L1py is the better receptor for both substrates, thanks to the simultaneous presence of a pyridine linker functionalized at its 2,6 positions and of a flexible linear tetraamine chain. In fact, these structural features allow a stronger interaction of PMG and ATP with both the protonated tetraamine moiety and the Zn(ii)-cyclam core.     

Lanthanide-mediated triangular cationic assemblies: structural and physico-chemical properties

This contribution investigates Ln(III) complexes formed with a small ditopic ligand, L1, and their structural, thermodynamic and photophysical properties. The spectrophotometric and NMR titrations evidence the triangular assemblies [Ln(3)(L1-H)(3)](6+) at stoichiometric conditions and their properties are discussed in relation to L2-containing analogues. In addition, the dinuclear species, [Ln(2)(L1-H)](5+), is observed with an excess of metal.     

Electrochemical properties of gold nanoparticles assembly at polarised liquid|liquid interfaces

Capacitance measurements of a polarised liquid|liquid interface show that the capacitance of the interface increases in the presence of an adsorbed monolayer of citrate-coated gold nanoparticles. This unusual observation can be explained by an increase of the interfacial charge density or by an increase of the interfacial corrugation. This study shows that capacitance measurements provide a method to monitor metallic film formation at ITIES.     

Evaluation of an hPXR reporter gene assay for the detection of aquatic emerging pollutants: screening of chemicals and application to water samples

Many environmental endocrine-disrupting compounds act as ligands for nuclear receptors. Among these receptors, the human pregnane X receptor (hPXR) is well described as a xenobiotic sensor to various classes of chemicals, including pharmaceuticals, pesticides, and steroids. To assess the potential use of PXR as a sensor for aquatic emerging pollutants, we employed an in vitro reporter gene assay (HG5LN-hPXR cells) to screen a panel of environmental chemicals and to assess PXR-active chemicals in (waste) water samples. Of the 57 compounds tested, 37 were active in the bioassay and 10 were identified as new PXR agonists: triazin pesticides (promethryn, terbuthryn, terbutylazine), pharmaceuticals (fenofibrate, bezafibrate, clonazepam, medazepam) and non co-planar polychlorobiphenyls (PCBs; PCB101, 138, 180). Furthermore, we detected potent PXR activity in two types of water samples: passive polar organic compounds integrative sampler (POCIS) extracts from a river moderately impacted by agricultural and urban inputs and three effluents from sewage treatment works (STW). Fractionation of POCIS samples showed the highest PXR activity in the less polar fraction, while in the effluents, PXR activity was mainly associated with the dissolved water phase. Chemical analyses quantified several PXR-active substances (i.e., alkylphenols, hormones, pharmaceuticals, pesticides, PCBs, bisphenol A) in POCIS fractions and effluent extracts. However, mass-balance calculations showed that the analyzed compounds explained only 0.03% and 1.4% of biological activity measured in POCIS and STW samples, respectively. In effluents, bisphenol A and 4-tert-octylphenol were identified as main contributors of instrumentally derived PXR activities. Finally, the PXR bioassay provided complementary information as compared to estrogenic, androgenic, and dioxin-like activity measured in these samples. This study shows the usefulness of HG5LN-hPXR cells to detect PXR-active compounds in water samples, and further investigation will be necessary to identify the detected active compounds.