Indium‐Bridged [1]Ferrocenophanes

Indium‐bridged [1]ferrocenophanes ([1]FCPs) and [1.1]ferrocenophanes ([1.1]FCPs) were synthesized from dilithioferrocene species and indium dichlorides. The reaction of Li₂fc?tmeda (fc=(H₄C₅)₂Fe) and (Mamx)InCl₂ (Mamx=6‐(Me₂NCH₂)‐2,4‐tBu₂C₆H₂) gave a mixture of the [1]FCP (Mamx)Infc ( 4₁ ), the [1.1]FCP [(Mamx)Infc]₂ ( 4₂ ), and oligomers [(Mamx)Infc]_n ( 4 _n ). In a similar reaction, employing the enantiomerically pure, planar‐chiral (S_p,S_p)‐1,1′‐dibromo‐2,2′‐diisopropylferrocene ( 1 ) as a precursor for the dilithioferrocene derivative Li₂fc^iPr2, equipped with two iPr groups in the α position, gave the inda[1]ferrocenophane 5₁ [(Mamx)Infc^iPr2] selectively. Species 5₁ underwent ring‐opening polymerization to give the polymer 5 _n . The reaction between Li₂fc^iPr2 and Ar′InCl₂ (Ar′=2‐(Me₂NCH₂)C₆H₄) gave an inseparable mixture of the [1]FCP Ar′Infc^iPr2 ( 6₁ ) and the [1.1]FCP [Ar′Infc^iPr2]₂ ( 6₂ ). Hydrogenolysis reactions (BP86/TZ2P) of the four inda[1]ferrocenophanes revealed that the structurally most distorted species ( 5₁ ) is also the most strained [1]FCP.     

溶剂热法合成花朵状钴磁性粉体及表征

采用一种简单的溶剂热法成功的合成了花朵状的钴磁性粉体。通过X射线粉末衍射(XRD),扫描电子显微镜(SEM)等对样品进行物相与形貌的表征。结果表明样品为六排堆积(hcp)和面心立方结构(fcc)混合结构的钴单质,形貌为由很多个厚度约为50～150 nm的菱形花瓣构成的花朵状结构,每个花朵的尺寸约为2μm左右。采用振动样品磁强计(VSM)测试了样品的磁性能,测试表明样品在室温下表现出铁磁性,饱和磁化强度(Ms)为140 emu.g-1,剩磁(Mr)为9.4 emu.g-1,矫顽力(Hc)为280 Oe。     

Exploration of tertiary aminosquaramide bifunctional organocatalyst in controlled/living ring‐opening polymerization of l‐lactide

A series of tertiary aminosquaramides as bifunctional organocatalysts in the ring‐opening polymerization (ROP) of l ‐lactide (l ‐LA) were developed, allowing the activation of both the l ‐LA monomer and the alcohol group of the initiator/propagating species. Further, the impact of tertiary nitrogen substituents on catalytic activity in ROP of l ‐LA was explored. The tertiary aminosquaramide— an air‐stable and moisture‐stable catalyst—exhibited superior activity in contest with thiourea counterpart when both were equipped with a similar tertiary amine group. Kinetic and chain‐extension experiments indicated that the formed poly(l ‐LA) is featured with narrow polydispersity and high end‐group fidelity, hallmarks of a living polymerization process. The initiator efficiency was further executed at ease by preparation of an ABA triblock copolymer poly (l ‐LA)‐b‐poly (ethylene glycol)‐b‐poly (l ‐LA) in the presence of a dual‐headed PEG macroinitiator. ¹H NMR titration experiments suggested a bifunctional catalytic mechanism, wherein both the l ‐LA monomer and the propagating hydroxyl group were activated en route to polymerization. The ¹H NMR, SEC, and MALDI‐TOF MS measurements validated the quantitative incorporation of the initiator in the polymeric chains and enchainment over competitive trans‐esterification reaction. Overall, the structure‐activity relationships were surveyed to uncover aminosquaramide as a new bifunctional dual hydrogen‐bond donor catalyst for living ROP of l ‐LA. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2483–2493     

Mixed-solvent thermal synthesis and magnetic properties of flower-like microstructured nickel

Flower-like microstructured nickel was synthesized by a facile mixed-solvent thermal process. The structure, morphology, and magnetic properties of the reaction products were investigated, respectively, by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The results showed that the products consisted of a face-centered cubic (fcc) structure with lattice constant of α = 3.524 Å. The average diameter of flower-like microstructured nickel was about 5 μm and the thickness of a single flake was about 100 nm. Magnetic measurement showed that these powders exhibited ferromagnetic characteristics.     

溶剂热法制备翠玉状Fe3O4微晶及表征

采用溶剂热法合成粒径为1～2 μm的翠玉状的Fe3O4晶粒.样品物相用X射线衍射(XRD)仪表征,形貌通过电子扫描显微镜(SEM)观测.所得样品的磁性用振动样品磁强计(VSM)测试,结果显示出铁磁性:饱和磁化强度Ms为89.7 emu/g,剩余磁化强度Mr为6.7 emu/g,矫顽力Hc为107.1 Oe.     

Hydrothermal growth of octahedral Fe3O4 crystals

This paper reports the growth of octahedral magnetic Fe3O4 particles from iron powders via a simple alkaline hydrothermal process. The chemical compositions and morphologies of the as-grown Fe3O4 particles were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, and scanning electron microscopy （SEM）. Structure characterization showed that the phase structure of the prepared particles evolved from α-Fe to pure Fe3O4 with increasing concentration of KOH, indicating the important role of KOH concentration on the formation of the magnetite octahedron. The magnetic properties of samples were also studied by means of a vibrating sample magnetometer （VSM）. The pure magnetite Fe3O4 octahedrons exhibited a relatively high saturation magnetization of 96.7 emu/g.     

Einen doppelten Scheidetrichter

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