-
[show abstract]
[hide abstract]
ABSTRACT: We report the synthesis, crystal structures, thermal and magnetic characterizations of a family of metal-organic frameworks adopting the niccolite (NiAs) structure, [dmenH(2)(2+)][M(2)(HCOO)(6)(2-)] (dmen=N,N'-dimethylethylenediamine; M=divalent Mn, 1Mn; Fe, 2Fe; Co, 3Co; Ni, 4Ni; Cu, 5Cu; and Zn, 6Zn). The compounds could be synthesized by either a diffusion method or directly mixing reactants in methanol or methanol-water mixed solvents. The five members, 1Mn, 2Fe, 3Co, 4Ni, and 6Zn are isostructural and crystallize in the trigonal space group P31c, while 5Cu crystallizes in C2/c. In the structures, the octahedrally coordinated metal ions are connected by anti-anti formate bridges, thus forming the anionic NiAs-type frameworks of [M(2)(HCOO)(6)(2-)], with dmenH(2)(2+) located in the cavities of the frameworks. Owing to the Jahn-Teller effect of the Cu(2+) ion, the 3D framework of 5Cu consists of zigzag Cu-formate chains with Cu-OCHO-Cu connections through short basal Cu-O bonds, further linked by the long axial Cu-O bonds. 6Zn exhibits a phase transition probably as a result of the order-disorder transition of the dmenH(2)(2+) cation around 300 K, confirmed by differential scanning calorimetry and single crystal X-ray diffraction patterns under different temperatures. Magnetic investigation reveals that the four magnetic members, 1Mn, 2Fe, 3Co, and 4Ni, display spin-canted antiferromagnetism, with a Néel temperature of 8.6 K, 19.8 K, 16.4 K, and 33.7 K, respectively. The Mn, Fe, and Ni members show spin-flop transitions below 50 kOe. 2Fe possesses a large hysteresis loop with a large coercive field of 10.8 kOe. The Cu member, 5Cu, shows overall antiferromagnetism (both inter- and intra-chains) with low-dimensional characteristics.
Chemistry - An Asian Journal 08/2011; 6(11):3084-96. · 4.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Several carbon/tin oxide
composite anode materials are prepared through a novel and simple solution route. Powder x-ray diffraction and energy dispersive
analysis of x-ray measurements confirm that the nanosized
particles are homogeneously dispersed in the carbon matrix. Both the content of
and the carbonization temperature play an important role on the electrochemical performance of the
composites. The
anode material with 47%
, carbonized at
, has the optimal electrochemical performance. This material exhibits an initial charge capacity of
and an average reversible capacity of
during
at a current density of
.
Journal of The Electrochemical Society. 02/2011; 158(3):A296-A301.
-
[show abstract]
[hide abstract]
ABSTRACT: Ankylosing spondylitis (AS) is an autoimmune disease which has a strong association with HLA-B27. Its pathogenesis includes the interaction between microorganism and host, the recognition of MHC class I molecule by immune cells and the imbalance of the cytokine network and so on. Unfolded protein response (UPR) participates in the development of AS. And the activation of the IL-23/IL-17 axis, which is in the downstream of UPR, may make a critical contribution to the pathogenesis. UPR and IL-23/IL-17 axis open new avenues of investigation as well as identifying new therapeutic target in this disease.
Sheng li ke xue jin zhan [Progress in physiology] 02/2011; 42(1):16-20.
-
[show abstract]
[hide abstract]
ABSTRACT: Zirconia precursor nanowires were synthesized via the solvothermal reaction of zirconium tetra-n-propoxide Zr(OPr(n))(4) with ethylene glycol and 1-butyl-3-methyl imidazolium tetrafluoroborate ionic liquid at 160 degrees C. The as-synthesized nanowires were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), thermogravimetric and differential scanning calorimetric (TG-DSC) analysis, and infrared spectroscopy (IR), etc. The length of the as-synthesized nanowires reaches approximately 20 mum, and the width approximately 50 nm, giving an aspect ratio of a few hundreds. Upon calcination at elevated temperatures, the zirconia precursor nanowires transform from relative dense structure into highly porous ZrO(2) nanowires consisting of interconnected nanocrystallites; in addition the length of the nanowires is greatly reduced. Cyclic voltammetry measurement shows that the modification of the graphite electrode with the ZrO(2) nanowires greatly enhances sensitivity of the detection of vanadium, suggesting that ZrO(2) nanowires may find important applications in vanadium(V) determination using electroanalytical methods with chemically modified electrode technique.
Journal of Colloid and Interface Science 03/2009; 333(2):734-40. · 3.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Tin oxide (SnO2) microspheres with an average 2.5 microm in diameters have been successfully synthesized through a rapid hydrothermal process heating by microwave in the presence of an ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate. X-ray diffraction, scanning electron microscopy and transmission electron microscopy are used to characterize the morphology and crystalline structure of the microspheres. The as-synthesized SnO2 microspheres exhibit a tetragonal rutile structure. The mechanism of the microspheres formation is proposed.
Journal of Colloid and Interface Science 04/2008; 319(1):115-22. · 3.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Copper oxalate nanowires were synthesized via the reaction of Cu(CH3COO)2·4H2O and oxalic acid in ethanol solution with the aid of 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) ionic liquid under solvothermal conditions at 180 °C. The as-synthesized nanowires were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetric analysis (TG-DSC). The length of the nanowires reaches ∼10 μm, and the width ∼30 nm, giving an aspect ratio of a few hundreds. The formation of the nanowires follows a novel mechanism based on the reorganization of a copper oxalate solid phase. The copper oxalate nanowires can further transform from a dense structure (enclosed by a smooth surface) into highly porous CuO nanowires consisting of interconnected nanocrystallites.
Journal of Crystal Growth.
