Search

In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a new polyiodoantimonate (HpipeH2)2[Sb2I10](I2) and analyzed its crystal and electronic structure by application of X-ray crystal structure analysis, Raman and diffuse reflectance spectroscopies, and quantum chemical calculations. It was demonstrated that I2 molecules link Sb2I10 edge-sharing octahedra into zig-zag chains, whereas the organic cations link inorganic anionic chains into a 3D structure featuring a complex pattern of covalent bonds and non-covalent interactions. Overall, these features provide the background for forming the electronic structure with a narrow band gap of 1.41 eV, therefore being a versatile tool for optimizing the band gap of a potential light-harvesting hybrid compound. [ABSTRACT FROM AUTHOR]

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO3-based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO3-derived catalysts combined with the re-oxidation of spent catalysts to SmCoO3 onto its long-term performance was studied. In particular, the modification of heterometallic precursors by supercritical antisolvent precipitation (SAS) considerably decreases coke formation upon the exploitation of the derived SmCoO3 sample. Moreover, the re-oxidation of the corresponding spent catalysts followed by pre-heating under N2 affords catalysts that stably provide syngas yields of 88–95% for at least 41 h at 900 °C. The achieved yields are among the highest ones currently reported for DRM catalysts derived from both LnMO3 perovskites and related oxides. The origins of such good performance are discussed. Given the simplicity and availability of all the applied methods and chemicals, this result opens prospects for exploiting SAS in the design of efficient DRM catalysts. [ABSTRACT FROM AUTHOR]

The Pd (II) complexes trans‐[PdCl2(μ‐L)]2 and [Pd(acac)(L)][BF4] (L = RS(CH2)2O(CH2)2SR, R = Me, Et, nPr, iPr, nBu, iBu, n‐hexyl, benzyl) were obtained through the reaction of Pd(cod)Cl2 or [Pd(acac)(MeCN)2][BF4] with one equivalent of oxadithioether (L). The structural features of these complexes were analyzed by nuclear magnetic resonance (NMR) and Fourier‐transform infrared spectroscopy (FTIR), as well as electrospray ionisation mass spectrometry and density functional theory calculations. The complexes di‐μ‐(2,10‐dimethyl‐6‐oxa‐3,9‐dithiaundecane‐κ2S,S′)‐bis[trans‐dichloropalladium (II)] and (acetylacetonate‐κ2O,O′)(2,10‐dimethyl‐6‐oxa‐3,9‐dithiaundecane‐κ2S,S′)palladium (II) tetrafluoroborate were characterized by X‐ray diffractometry. The X‐ray structures of each complex indicate an axial M–O interaction formed by the endodentate conformation of the oxadithioether ligand. Palladium (II) dichloride complexes with oxadithioethers were demonstrated to have a 16‐membered dinuclear structure with a trans‐configured S2PdCl2 fragment. In the case of cationic palladium acetylacetonate complexes, only mononuclear complexes with a cis configuration of the oxadithioether fragment were observed. Variable temperature 1H and 13C NMR studies of the complexes demonstrate dynamic bonding of the oxadithioether ligands consistent with the presence of diastereoisomers that differ in the orientation of the S‐R groups along with both endodentate and exodentate bonding modes in solution. FTIR studies of the complexes indicate the presence of isomers in the solid state. The palladium catalyst precursors trans‐[PdCl2(μ‐L)]2 and [Pd (acac)(L)][BF4] were found to be active in the addition polymerization of norbornene. In the presence of cocatalysts, such as diisobutylaluminum chloride and boron trifluoride etherate, Pd (II) complexes exhibited activities in the range of 105 to 107 g of polymer (mol of Pd)−1 h−1. The catalyst systems showed good thermostability with a high activity of 1.43 × 107 g of polymer (mol of Pd)−1 h−1 at 75°C. These complexes are examples of Pd (II) complexes bearing thioether ligands, which are rarely observed in the field of olefin polymerization. [ABSTRACT FROM AUTHOR]

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO 3 -based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO 3 -derived catalysts combined with the re-oxidation of spent catalysts to SmCoO 3 onto its long-term performance was studied. In particular, the modification of heterometallic precursors by supercritical antisolvent precipitation (SAS) considerably decreases coke formation upon the exploitation of the derived SmCoO 3 sample. Moreover, the re-oxidation of the corresponding spent catalysts followed by pre-heating under N 2 affords catalysts that stably provide syngas yields of 88-95% for at least 41 h at 900 °C. The achieved yields are among the highest ones currently reported for DRM catalysts derived from both LnMO 3 perovskites and related oxides. The origins of such good performance are discussed. Given the simplicity and availability of all the applied methods and chemicals, this result opens prospects for exploiting SAS in the design of efficient DRM catalysts.