617 research outputs found
catena-Poly[[bis(2-hydroxy-2-phenylacetato-κ2 O 1,O 2)zinc(II)]-μ-1,2-di-4-pyridylethane-κ2 N:N′]
The title compound, [Zn(C8H6O3)2(C12H12N2)]n, consists of [Zn(Hopa)2] (H2opa = 2-hydroxy-2-phenylacetic acid or mandelic acid) units bridged by 1,2-di-4-pyridylethane (bpe) ligands, forming a polymeric chain developing parallel to the b axis. The bridging bpe ligand is arranged around a twofold axis passing through the middle of the ethane C—C bond. The geometry around the ZnII ion is distorted octahedral, constructed by four O atoms from two Hopa− ligands and two N atoms from two bridging bpe ligands. O—H⋯O hydrogen bonds link the chains, forming a three-dimensional network
Unveiling the Role of Ruthenium in Layered Sodium Cobaltite Toward High-Performance Electrode Enabled by Anionic and Cationic Redox
The effect of Ru substitution on the structure and electrochemical properties of P2-type Na0.67CoO2 is investigated. The first-discharge capacities of Na0.67CoO2 and Na0.6 [Co0.78Ru0.22]O2 materials are 128 and 163 mAh g−1 (23.5 mA g−1), respectively. Furthermore, the rate capability is improved due to the electro-conducting nature of Ru doping. Operando X-ray diffraction analysis reveals that the Na0.67CoO2 does not undergo a phase transition; however, multiple Na+/vacancy ordered superstructures within the P2 phase appear during Na+ extraction/insertion. In contrast, the Na0.6[Co0.78Ru0.22]O2 material undergoes a P2–OP4 phase transition during desodiation, with no formation of Na+/vacancy ordering within the P2 phase. The increased discharge capacity of Na0.6[Co0.78Ru0.22]O2 is most likely associated with additional cationic Ru4+/Ru5+ redox and increased anionic O2−/(O2n−) redox participation. Combined experimental (galvanostatic cycling, X-ray absorption spectroscopy, differential electrochemical mass spectrometry) and theoretical (density functional theory calculations) studies confirm that Ru substitution provokes the oxygen-redox reaction and that partial O2 release from the oxide lattice is the origin of the reaction. The findings provide new insight for improving the electrode performance of cathode materials via 4d Ru substitution and motivate the development of a new strategy for the design of high-capacity cathode materials for sodium-ion batteries.</p
Tetra-μ-benzoato-bis[(6-methylquinoline)copper(II)]
In the title compound, [Cu2(C7H5O2)4(C10H9N)2], the paddle-wheel-type dinuclear complex is constructed by four bridging benzoate groups and two terminal 6-methylquinoline ligands. The asymmetric unit contains one-half of the whole molecule, and there is an inversion center at the mid-point of the Cu⋯Cu bond. The octahedral coordination of each Cu atom, with four O atoms in the equatorial plane, is completed by the N atom of the 6-methylquinoline molecule [Cu—N = 2.212 (2) Å] and by another Cu atom [Cu⋯Cu = 2.6939 (13) Å]. The Cu atom lies 0.234 Å out of the plane of the four O atoms. The molecular packing is stabilized by one intramolecular C—H⋯O as well as C—H⋯π and π–π interactions
Engineering Transition Metal Layers for Long Lasting Anionic Redox in Layered Sodium Manganese Oxide
Oxygen-redox-based-layered cathode materials are of great importance in realizing high-energy-density sodium-ion batteries (SIBs) that can satisfy the demands of next-generation energy storage technologies. However, Mn-based-layered materials (P2-type Na-poor Nay[AxMn1−x]O2, where A = alkali ions) still suffer from poor reversibility during oxygen-redox reactions and low conductivity. In this work, the dual Li and Co replacement is investigated in P2-type-layered NaxMnO2. Experimentally and theoretically, it is demonstrated that the efficacy of the dual Li and Co replacement in Na0.6[Li0.15Co0.15Mn0.7]O2 is that it improves the structural and cycling stability despite the reversible Li migration from the transition metal layer during de-/sodiation. Operando X-ray diffraction and ex situ neutron diffraction analysis prove that the material maintains a P2-type structure during the entire range of Na+ extraction and insertion with a small volume change of ≈4.3%. In Na0.6[Li0.15Co0.15Mn0.7]O2, the reversible electrochemical activity of Co3+/Co4+, Mn3+/Mn4+, and O2-/(O2)n- redox is identified as a reliable mechanism for the remarkable stable electrochemical performance. From a broader perspective, this study highlights a possible design roadmap for developing cathode materials with optimized cationic and anionic activities and excellent structural stabilities for SIBs.</p
Light-chain amyloidosis presenting with rapidly progressive submucosal hemorrhage of the stomach
SummaryThe gastrointestinal tract is frequently in involved light-chain (AL) amyloidosis, but significant hemorrhagic complications are rare. A 71-year-old man presented to our hospital with dyspepsia and heartburn for 1 month. Gastroscopy revealed a large submucosal hematoma at the gastric fundus. Two days later, a follow-up gastroscopy indicated extensive expansion of the hematoma throughout the upper half of the stomach. The hematoma displayed ongoing expansion during the endoscopic examination, suggesting that rupture was imminent. Emergency total gastrectomy was performed, and amyloidosis was confirmed after examining the surgical specimen. Bone marrow examination revealed multiple myeloma, and serum immunoglobulin assay confirmed the diagnosis of myeloma-associated AL amyloidosis. At manuscript submission, the patient was doing well and was undergoing chemotherapy
Recommended from our members
PS49. Shifted Circadian Phase in Manic Episode was Returned to Normal after Treatment in Bipolar Disorder
- …