Search

Li–S rechargeable batteries are desirable for electric transportation because of their low cost, environmental friendliness, and superior energy density. However, the Li–S system has yet to conquer the market owing to its drawbacks such as soluble polysulfide formation. To tackle this issue, we report herein a strategy based on the use of a micro-porous copper metal–organic framework named CuMOF as a host material for sulfur immobilization via chemical bonds between sulfur and the MOF structure. CuMOF has been obtained by simple chemical synthesis using copper salt and benzene-1,3,5-tricarboxylic acid as the ligand. Then, by the melt-diffusion method, sulfur-impregnated CuMOFS material is finally fabricated. As a cathode material for Li–S batteries, the CuMOFS cathode delivers a capacity of 1051.3 mA h g−1 after 300 cycles at a charge/discharge current density of 200 mA g−1. It is worth noting that the main cathode structure can retain more than 19.3 wt% sulfur due to the CuMOF host, which dramatically decreases capacity fading and improves coulombic efficiency during prolonged charge/discharge cycling. The XPS peaks of CuMOFS are assigned according to the information obtained from density functional theory (DFT) calculations. Linear scaling DFT structure relaxation for a model with ＞1000 atoms is carried out to exemplify the interactions between CuMOF framework and embedded Li2S. The excellent electrochemical performance can be due to firm confinement of sulfur/polysulfides because of strong chemical interactions between carbon and sulfur species in the CuMOF host. [ABSTRACT FROM AUTHOR]

Using the bi- and mono-triazole ligand, a series of novel cobalt(II) complexes [Co(L1)2(NCS)2(H2O)2] (1), [Co2(NCS)4(H2O)6]·3L2(2) and [Co(L3)2(NCS)2(H2O)2] (L1= 4–3-pyridine-1,2,4-triazole, L2= 1,4-bis(4H-1,2,4-triazol-4-yl)benzene, and L3= 2,6-di(1,2,4- triazol-4-yl)pyridine) have been synthesized. The crystal structures of1–3have been determined by single-crystal X-ray diffraction analysis.1and3has the mononuclear fundamental structure unit while2form the dinuclear structure unit.1–3were furthermore assembled into three-dimensional (3D) supramolecular complex via the intermolecular hydrogen bonds and aromatic π–π stacking interactions. The complexes1–3also have been characterized by elemental analysis, FT-IR, and TGA analysis. Variable temperature magnetic susceptibility measurement (2–300 K) also reveals weak anti-ferromagnetic interactions in2. [ABSTRACT FROM PUBLISHER]

Under the hydrothermal conditions, based on a highly flexible H2L (2,2′-thiodiacetic acid) ligand and corresponding lead(II) salts, a novel lead(II) inorganic-organic hybrid framework {Pb3(μ8-L)2(μ2-Br)2}n(1) has been isolated. In 1, 1D infinite Pb-O-Pb and Pb-Br-Pb connectivity can be observed, which are interlinked forming a novel 2D inorganic-organic framework with I2O0type. The six-coordinated geometry of Pb1 in the hemidirected geometry and eight-coordinated geometry of Pb2 in the holodirected geometry in 1 also can be observed. TG analysis and solid-state fluorescent spectrum of 1 have also been investigated. The variable lead(II) geometries and coordination numbers together with flexible coordination modes of deprotonated 2,2′-thiodiacetate ligand also reveal great potential in the rational design and deliberate construction of those novel inorganic-organic hybrid materials. Supplementary material is available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file.] [ABSTRACT FROM PUBLISHER]

Using the achiral 1,4-naphthalenedicarboxylic acid (H2L) ligand and corresponding cadmium(II) salts, under hydrothermal conditions, a novel 3D chiral inorganic-organic hybrid complex with the formula [Cd(μ6-L)(DMF)]nhas been isolated and characterized by single-crystal X-ray diffraction, FT-IR, TGA, and luminescent analysis. The crystal crystallizes in the chiral space group P212121,a= 6.7180(10) Å,b= 13.507(2) Å,c= 15.229(2) Å,Z= 4, the flack parameter is near zero (–0.02(4)). Two kinds of 1D infinite right-handed Cd-O-Cd helical chains can be observed, which are further interlinked into 1D infinite Cd-O-Cd linkage in a unique arrangement way. Solid-state luminescent spectrum of 1 also has been investigated indicating the strong emission band centered at 494 nm upon excitation at 370 nm. The result also represents a good example of the construction of those chiral inorganic-organic hybrid frameworks containing infinite M-O-M linkage using the achiral precursor. Supplementary materials are available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file. [ABSTRACT FROM AUTHOR]

Using the tripodal N-(carbamoylmethyl)iminodiacetato acid (H2ADA) ligand and corresponding Ag(I) and Cr(III) salts, a novel two-dimensional (2D) heterometallic Ag(I)-Cr(III) coordination polymer [AgCr(ADA)2]n(1) has been isolated. H2ADA are deprotonated into ADA2−, which adopts a novel asymmetrical η1, η1, η1, η2, μ5-pentadentate coordination mode to bridge neighboring seven-coordinated Ag(I) and five-coordinated Cr(III) ions forming a 2D inorganic-organic hybrid framework containing 2D Ag-O-Cr inorganic connectivity. The solid-state fluorescence spectrum of 1 was also investigated exhibiting the maximum emission peak at 609 nm while no fluorescence emission band can be observed for the free ligand. 1 also represents a luminescent heterometallic hybrid framework with scarcely reported pentacoordinated deprotonated H2ADA ligands. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file. [ABSTRACT FROM AUTHOR]

Under hydrothermal conditions, using 5-methyl-pyrazine-2-carboxylic acid (HL) and lead(II) bromide, a new 2D lead(II) framework [Pb(L)(μ2-Br)(H2O)]n(1) can be isolated, in which infinite Pb-O-Pb and Pb-Br-Pb helical chains can be observed. The crystal crystallizes in the monoclinic system, space groupP2(1)/c,a= 7.5493(10),b= 6.6775(9),c= 19.335(3) Å,β =92.884(2)°, andZ= 1. The X-ray analysis shows that strong O-H···N and weak O-H···Br hydrogen bonds further extending 1 into a 3D supramolecular packing architecture. Solid state luminescent spectrum of 1 also has been investigated indicating strong emission bands centered at 453 nm. [ABSTRACT FROM PUBLISHER]