采用基于铬离子构筑的金属有机骨架化合物(MIL-53-Cr、MIL-101-Cr、MIL-102-Cr)为模板,通过简单的煅烧处理制备出三种不同形貌的Cr2O3。实验结果表明以MIL-102-Cr作为前驱体制备的Cr2O3具有较规则的中空结构形貌,当其作为锂离子电池负极材料时展现出最优异的电化学性能,当电流为0.1 C时,首次放电容量为840 m Ah/g,在电流为1 C循环100次后,可逆容量可以保持在200 m Ah/g。
In this work, a series of new metal phosphonates were hydrothermally synthesized and structurally characterized based on m-xylylenediphosphonic acids(H4L), including[M(H2L)(bpy)](M = Mn 1, Co 2), [MH2L)(phen)](M = Co3, Cu 4), and [Cu2(H2L)2(bpy00)2] 5(bpy = 2,20-bipyridine,phen = 1,10-phenanthroline, bpy00= 4,40-dimethyl-2,20-bipyridine). X-ray diffraction indicated that compounds 1 and2 were isomorphic. Complexes 3 and 4 were shown to crystallize in different space groups but had similar crystallographic units. In the complexes, H4 L was seen to partially deprotonate to afford H2L2-. The H2L2-ligands in 1–4functioned as tetradentate ligands with each phosphonate group adopting bidentate coordination mode with two M centers to generate a 2D layer. In addition, the H2L2-anions in5 functioned as tridentate ligands with one phosphonate group adopting the bidentate mode and another phosphonate group adopti ng the monodentate mode, thus linking three Cu atoms to provide a 1D chain. The IR and thermal stabilities of these compounds were subsequently examined.
Yu YangWei XuYuanxin LiMeng LiuYiheng ZhangLei Wang
Although the numbers of co-crystals,salts,polymorphs,hydrates,and solvates are growing steadily,trimers that contain both inorganic and organic acids are still very rare in the Cambridge Structural Database(CSD).When 3,5-dihydroxybenzoic acid was crystallized readily with 6-methyl-1,3,5-triazine-2,4-diamine in a 4:3 ratio of ethanol and water by adding a few drops of nitric acid upon slow evaporation in ambient conditions,6-methyl-1,3,5-triazine-2,4-diamine and 3,5-dihydroxybenzoic acid with the nitric acid form of 1:1:1 an inorganic-organic salt formulated as[(C4H8N5+)·(NO3-)·(C7H6O4)].The supramolecular architecture,which is quite elegant and simple,appeared as stacking of a 3D network in adduct.Proton transfer from the HNO3to 6-methyl-1,3,5-triazine-2,4-diamine N acceptor(triazine N)occurred in the organic salt and led to the ionic heterosynthon in the structure.Cooperation among the–COOH,–OH,NO3–,and–NH–functional groups for the observed hydrogen bond synthon was examined in the structure.In adduct,recognition among the constituents is established through N–H···O,O–H···N,and O–H···O hydrogen bonds.The agomelatine molecules are linked through the intermolecular hydrogen bonding interactions(O–H···O)to form a 1D chain.In addition,the nitric acid anions and base cations act as donors and acceptors of hydrogen bonds and interlink,almost to co-planarity,the hydrogen-bonded chains through interchain N–H···O,O–H···N,as well as O–H···O interactions into a 2D sheet structure.Persistent N–H···O interactions were found to play an important role in the formation of the final 3D array.The salt was characterized by elemental analysis,IR,thermogravimetric analysis,and singlecrystal X-ray diffraction,to better understand how intermolecular interactions influence its supramolecular assembly.
Three polymeric heterometallic clusters with 1D, 2D, and 3D frameworks, constructed from a cyclic vanadate {V4O12}4- building block and three geometric constraint ligands, were synthesized by a one-pot self-assembly reaction. Z-scan experiments demonstrated that all the three cluster polymers have large hyperpolarizability y values. TD-DFT calculations afforded insight into the electronic transitions and spectral characterization of these novel NLO molecular materials.
LIU FaQianWANG LeiGUO JiXiLI WeiHuaLI ChaoQinJIN YanLingLI RongXunJIAN FangFang
