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Mohammad El-khateeb Hassan Abul-Futouh Hadil Alshurafa Helmar Görls Wolfgang Weigand 《应用有机金属化学》2020,34(11):e5940
Substitution of carbonyl ligands of the hydrogenase model complex [Fe2(μ-SeCH2CH(Me)CH2Se-μ)(CO)6] ( A ), by 1,1′-bis (diphenylphosphino)ferrocene (dppf), 1,2-bis (diphenylphosphino)benzene (dppbz) or 1,2-bis (diphenylphosphino)acetylene (dppac) is investigated. It is found that the reaction product depends on the diphosphine used. In the case of dppf, the product is an intramolecular bridged disubstituted complex [Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)4{μ,κ1,κ1(P,P)-dppf}] ( 1 ), while the dppac-reaction produces an intermolecular bridged tetra-iron model [Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)5]2{μ,κ1,κ1(P,P)-dppac} ( 2 ). However, the dppbz-reaction gives [Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)4{κ2(P,P)-dppbz}] ( 3 ) in which the dppbz ligand is bonded to one Fe atom in a chelated manner. The newly prepared complexes ( 1 – 3 ) have been characterized by elemental analysis, IR, 1H-, 13C{H}-, 31P{H}-, 77Se{H}-NMR spectroscopy and X-ray structure determination. The electrochemical behavior of 2 and 3 , in absence and presence of acid, is described by cyclic voltammetric measurements in CH2Cl2. 相似文献
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Curcumin is a polyphenolic compound possessing interesting anti-inflammatory and antioxidant properties and has the ability to induce the defensive protein heme oxygenase-1 (HO-1). The objective of this study was to investigate whether curcumin protects against cold storage-mediated damage of human adult atrial myoblast cells (Girardi cells) and to assess the potential involvement of HO-1 in this process. Girardi cells were exposed to either normothermic or hypothermic conditions in Celsior preservation solution in the presence or absence of curcumin. HO-1 protein expression and heme oxygenase activity as well as cellular damage were assessed after cold storage or cold storage followed by re-warming. In additional experiments, an inhibitor of heme oxygenase activity (tin protoporphyrin IX, 10 microM) or siRNA for HO-1 were used to investigate the participation of HO-1 as a mediator of curcumin-induced effects. Treatment with curcumin produced a marked induction of cardiac HO-1 in normothermic condition but cells were less responsive to the polyphenolic compound at low temperature. Cold storage-induced damage was markedly reduced in the presence of curcumin and HO-1 contributed to some extent to this effect. Thus, curcumin added to Celsior preservation solution effectively prevents the damage caused by cold-storage; this effect involves the protective enzyme HO-1 but also other not yet identified mechanisms. 相似文献
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Ahmed H. Al Sharie Tamam El-Elimat Ruba S. Darweesh Samer Swedan Zaina Shubair Reema Al-Qiam Hadil Albarqi 《应用有机金属化学》2020,34(8):e5667
Zinc oxide nanoparticles have attracted significant interest in recent years due to their unique multifunctional chemical and physical properties along with their biological activities. This study demonstrated for the first time the biogenetic synthesis of zinc oxide nanoparticles by utilization of the methanolic extract of Hypericum triquetrifolium (HT). The obtained nanoparticles (HT-ZnO) were characterized by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The shape of the resulted nanoparticles is fusiform nanoflowers with an average hydrodynamic size of 275.46 ± 0.20 nm and a zeta potential of −8.23 ± 0.26 mV. SEM micrographs revealed that HT-ZnO nanoflowers have a multi-process structure in which one of the processes is large and the others have similar smaller dimensions. The synthesized nanoflowers have an average length of 312.28 ± 78.93 nm and the tip of its processes has a width of 48.69 ± 9.71 nm. The antimicrobial activity of HT-ZnO nanoflowers was performed using microbroth dilution format. It showed a bactericidal mode of action against Gram-positive Staphylococcus aureus and Enterococcus faecalis with MIC/MBC values of 20 μg/mL and 5 μg/mL, respectively. MTT assay had revealed that HT-ZnO nanoflowers caused a dose-dependent decline in the viability of A549 adenocarcinomic human alveolar basal epithelial cells with an IC50 value of 20.45 μg/mL. The effect of HT-ZnO nanoflowers on the migration and colony formation abilities against the same cells was evaluated as well. In conclusion, zinc oxide nanoflowers were successfully synthesized using methanolic extract of H. triquetrifolium. The resulting particles showed a bactericidal effect against Gram-positiveS. aureus and E. faecalis and a cytotoxic activity against A549 cells. 相似文献
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Poly(ε-caprolactone)–graft–polystyrenes were successfully synthesized by grafting an azide end-functionalized polystyrene onto a PCL backbone with multiple pendant alkyne moieties using a “click” chemistry reaction. Both precursors, the PCL backbone and the PS side chains, were prepared separately by two different living/controlled mechanisms, ring-opening polymerisation and ATRP, respectively. Molecular weights, polydispersity indexes, and chemical compositions of the backbone and branches were controlled. The subsequent copper-catalysed Huisgen 1,3-dipolar cycloaddition of PS onto PCL was achieved at room temperature with high conversion. However, a bimodal molecular weight distribution was observed in size exclusion chromatography due to the presence of unreacted PS. Nevertheless, crude product was purified by selective fractionation in cyclohexane to achieve pure graft copolymers. 相似文献
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