混合价双核锰[Mn2(cyclen)2(μ-O)2](ClO4)3·4H2O的晶体结构和表征

The mixed-valence manganese(Ⅲ/Ⅳ) complex [Mn2(cyclen)2(μ-O)2](ClO4)3-4H2O (1) (cyclen=1,4,7,10-tetraazacyclododecan) with chemical formula C16H48Cl3Mn2N8O18 has been synthesized and characterized by single crystal X-ray diffraction analysis, elemental analysis, IR and electronic spectra. The results showed that the manganese(Ⅲ/Ⅳ) ions were six-coordinated by four nitrogen atoms from cyclen and two oxygen atoms from the oxygen bridge, forming a distorted octahedron geometry. There were two very strong peaks in the range of 400-700 nm in electronic spectrum, which was similar to Mn catalase and Mn ribonucleotide reductase extracted from organisms.Electrochemical study indicated that the complex underwent a quasi-reversible one-electron reduction and oxidation at E1/2=0.827 V in acetonitrile.     

Self‐Assembled Alluaudite Na2Fe3−xMnx(PO4)3 Micro/Nanocompounds for Sodium‐Ion Battery Electrodes: A New Insight into Their Electronic and Geometric Structure

A series of alluaudite Na₂Fe_3?xMn_x(PO₄)₃ microcompounds, which self‐assembled from primary nanorods, were prepared successfully through a solvothermal method. As a promising candidate cathode for sodium‐ion batteries, it is necessary to obtain a deeper understanding of the relationship between the structure and physicochemical properties of these materials. The local electronic and geometric environments were systematically investigated, for the first time, by using a combination of soft/hard X‐ray absorption, IR, and Mössbauer spectroscopy. The results show that the electrochemical performance is not only associated with morphology, but also with the electronic and crystalline structure. With the introduction of manganese into the lattice, the long‐range order maintains the isostructural framework and the lattice parameters expand as expected. However, for short‐range order, PO₄ tetrahedra and MO₆ octahedra (M=Fe and Mn) become more severely distorted as a function of Mn concentration. Meanwhile, larger MnO₆ octahedra will compress the space of FeO₆ octahedra, which will result in stronger core/electron–electron interactions for Fe, as characterized by hard/soft X‐ray absorption spectra. These slight changes in the electronic and local structures lead to different electrochemical performances with changes to the manganese content. Moreover, other physicochemical properties, such as magnetic behavior, are also confirmed to be correlated with these different electron interactions and local geometric environments.     

Synthesis of Cobalt Ion‐Based Coordination Polymer Nanowires and Their Conversion into Porous Co3O4 Nanowires with Good Lithium Storage Properties

Cobalt ion‐based coordination polymer nanowires were synthesized by using nitrilotriacetic acid (NA) as a chelating agent by a one‐step hydrothermal approach. In the synthesis, cobalt ions were bonded with amino or carboxyl groups of NA to form one‐dimension polymer nanowires, which can be confirmed by FTIR and TGA results. Our experimental results show that the morphologies of polymer nanowires greatly depend on the precursor salts, ratios between deionized water and isopropyl alcohol. The probable molecular formula and growth mechanism have been proposed. After heat treatment, the cobalt ion‐based coordination polymer nanowires can be converted into porous Co₃O₄ nanowires, which completely preserved the nanowire‐like morphology. When used as anodes in lithium‐ion batteries, the obtained porous Co₃O₄ nanowires exhibited a high reversible capacity of 810 mA h g^?1 and stable cyclic retention at 30th cycle. The good electrochemical performance could be attributed to the porous nanostructure of Co₃O₄, which provides pathways for easy accessibility of electrolytes and fast transportation of lithium ions.     

Synthesis, nuclear, and magnetic structures and magnetic properties of [Mn3(OH)2(SO4)2(H2O)2

[Mn(3)(OH)(2)(SO(4))(2)(H(2)O)(2)] and its deuterated analogue were synthesized by a hydrothermal technique and characterized by differential thermal analysis, thermogravimetric analysis, and IR spectroscopy. Its nuclear structure, determined by single-crystal X-ray analysis and Rietveld analysis of neutron powder-diffraction data, consists of a 3D network of chains of edge-sharing Mn(1)O(6), running along the c axis, connected by the apices of Mn(2)O(6) and SO(4) units. It is isostructural to the nickel analogue. Determination of the magnetic structure and measurements of magnetization and heat capacity indicate the coexistence of both magnetic long-range ordering (LRO) and short-range ordering (SRO) below a Néel temperature of 26 K, while the SRO is retained at higher temperatures. The moments of the two independent Mn atoms lie in the bc plane, and that of Mn(1) rotates continuously by 54 degrees towards the c axis on decreasing the temperature from 25 to 1.4 K. While the SRO may be associated with frustration of the moments within a Mn(3) trimer, the LRO is achieved by antiparallel alignment of the four symmetry-related trimers within the magnetic unit cell. A spin-flop field, measured by dc and ac magnetization on a SQUID, is observed at 15 kOe.     

Synthesis,Structure and Magnetic Phase Transitions of the Manganese Succinate Hybrid Framework,Mn(C4H4O4)

An anhydrous manganese succinate, Mn(C₄H₄O₄), has been synthesised hydrothermally and studied by single‐crystal X‐ray diffraction. It adopts a succinate pillared structure in which layers of corner‐sharing MnO₆ octahedra alternate with sheets that contain chains of edge‐sharing octahedra. This unique 3D framework structure contains highly distorted MnO₆ octahedra, which are made possible by the lack of ligand field stabilisation energy for the high‐spin Mn²⁺ ion. Attempts to dope the structure with other divalent transition‐metal ions were accordingly unsuccessful. Magnetic susceptibility and heat capacity measurements indicate that Mn(C₄H₄O₄) undergoes antiferromagnetic ordering below 12 K, with a second antiferromagnetic transition at approximately 6 K. These two antiferromagnetic phases undergo further transitions in applied fields, underlining the subtle magnetic behaviour that is possible in inorganic–organic frameworks of this structural complexity.     

Characterization of Fe3O4/P(St-MPEO) Amphiphilic Magnetic Polymer Microspheres

IntroductionMagnetic microspheres have been widely usedin many fields,such as targetdrug,cell separationand enzyme immunoassay,since the past twentyyears because of their relatively rapid and easymagnetic separation[1] .Although a poly(ethyleneoxide) supported- catalyst system with a solublepolymer as the carrier can easily keep the activityand the selectivity of the catalyst,its recovery hasto be performed by filtration or precipitation fromthe reaction medium,which is time- consuming andener…     

Synthesis, Crystal Structure and Magnetic Properties of Novel Three-dimensional Frameworks [Mn(PDC)H2O]n

A novel coordination polymer, [Mn(PDC)H2O]n (1) (H2PDC＝pyridine-2,3-dicarboxylic acid), has been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. X-ray single crystal structural analyses revealed that two-dimensional frameworks were formed, and further assembled into a three-dimensional supramolecular structure bridged by PDC ligands. Moreover, the magnetic study of complex 1 shows weak antiferromagnetic interaction between the neighboring Mn(II) centers within the chains and even weak ferromagnetic interactions between the Mn(II) centers in different chains.     

Synthesis of Well‐Defined Bicapped Octahedral Iron Clusters [(trenL)2Fe8(PMe2Ph)2]n (n=0, −1)

The synthesis of polynuclear clusters with control over size and cluster geometry remains an unsolved challenge. Herein, we report the synthesis and characterization of open‐shell octairon clusters supported by two heptaamine ligands [o‐H₂NC₆H₄NH(CH₂)₂]₃N (^trenLH₉). The crystal structure of the all‐ferrous species ([^trenL)₂Fe₈(PMe₂Ph)₂] ( 1 ) displays a bicapped octahedral geometry with Fe? Fe distances ranging from 2.4071(6) to 2.8236(5) Å, where the ligand amine units are formally in amine, amide, and imide oxidation states. Several redox states of the octairon cluster are accessible, as ascertained using cyclic voltammetry. The one‐electron‐reduced clusters [M]⁺[(^trenL)₂Fe₈(PMe₂Ph)₂]^? (M=Bu₄N ( 2 a ); (15‐crown‐5)Na(thf) ( 2 b )) were isolated and characterized. Variable‐temperature magnetic susceptibility data indicates that the exchange coupling within the [Fe₈] core is antiferromagnetic which is attenuated upon reduction to the mixed valent anion.     

Structural and Magnetic Insights into the Trinuclear Ferrocenophane and Unexpected Hydrido Inverse Crown Products of Alkali‐Metal‐Mediated Manganation(II) of Ferrocene

With the aim of introducing the diisopropylamide [NiPr₂] ^? ligand to alkali‐metal‐mediated manganation (AMMMn) chemistry, the temperature‐dependent reactions of a 1:1:3 mixture of butylsodium, bis(trimethylsilylmethyl)manganese(II), and diisopropylamine with ferrocene in hexane/toluene have been investigated. Performed at reflux temperature, the reaction affords the surprising, ferrocene‐free, hydrido product [Na₂Mn₂ (μ‐H)₂{N(iPr)₂}₄]?2 toluene ( 1 ), the first Mn hydrido inverse crown complex. Repeating the reaction rationally, excluding ferrocene, produces 1 in an isolated crystalline yield of 62 %. At lower temperatures, the same bimetallic amide mixture leads to the manganation of ferrocene to generate the first trimanganese, trinuclear ferrocenophane, [{Fe(C₅H₄)₂}₃{Mn₃Na₂(NiPr₂)₂ (HNiPr₂)₂}] ( 2 ) in an isolated crystalline yield of 81 %. Both 1 and 2 have been characterised by X‐ray crystallographic studies. The magnetic properties of paramagnetic 1 and 2 have also been examined by variable‐temperature magnetisation measurements on powdered samples. For 1 , the room‐temperature value for χT is 3.45 cm³ K mol^?1, and on lowering the temperature a strong antiferromagnetic coupling between the two Mn ions is observed. For 2 , the room‐temperature value for χT is 4.06 cm³ K mol^?1, which is significantly lower than the expected value for three isolated paramagnetic Mn^II ions.