25 research outputs found
Microwave and Conventional Hydro(solvo)thermal Syntheses of Three Co(II) Coordination Polymers: Supramolecular Isomerism and Structural Transformations Accompanied by Tunable Magnetic Properties
Two
genuine supramolecular isomers [CoÂ(1,4-NDC)Â(5,5′-dmbpy)]<sub><i>n</i></sub> (<b>1α</b> and <b>1β</b>) and compound {[CoÂ(1,4-NDC)Â(5,5′-dmbpy)Â(H<sub>2</sub>O)<sub>2</sub>]<sub>2</sub>}<sub><i>n</i></sub> (<b>2</b>) (1,4-NDCH<sub>2</sub> = 1,4-naphthalenedicarboxylic acid, 5,5′-dmbpy
= 5,5′-dimethyl-2,2′-dipyridyl) have been synthesized
under conventional hydroÂ(solvo)Âthermal reactions. The highly crystalline
single-phases of <b>1β</b> and <b>2</b> with a well-defined
morphology could also be quickly prepared through microwave-assisted
syntheses within 5 min. Compared with <b>2</b>, which possesses
a one-dimensional (1D) single-chain-like structure, <b>1α</b> and <b>1β</b> feature the structures of 1D ladder-like
chain and two-dimensional (2D) layer, respectively, constructed from
the ring-like [Co<sub>2</sub>(OOCR)<sub>2</sub>] dimeric units interlinked
by the 1,4-NDC ligands. The drastic structural transformation from <b>1α</b> to <b>2</b>, as well as the interconversion
between <b>1β</b> and <b>2</b>, was observed, which
involved the reversible destruction and reconstruction of the Co<sub>2</sub>(OOCR)<sub>2</sub> unit during the transformation and was
associated with remarkable changes in magnetic properties. Remarkably,
microwave heating as an external driving force was adopted to achieve
structure transformation from <b>2</b> to <b>1β</b> within 5 min. This work demonstrates that the microwave technique
can be used as a quick and efficient synthetic method to investigate
the structural conversion between compounds and further bring about
property modulation
Hydrothermal synthesis and structural characterization of a three-dimensional coordination polymer on Ag(I)
<div><p></p><p>A new coordination polymer [Ag<sub>3</sub>(1,2,4-btc)]<sub>n</sub> (<b>1</b>) (1,2,4-H<sub>3</sub>btc = 1,2,4-benzenetricarboxylate) has been synthesized by hydrothermal method and characterized by X-ray single crystal diffraction, elemental analysis, IR spectrum and TGA. Compound <b>1</b> exhibits a three-dimensional (3D) network consisting of the 2D layer connected by the ligand 1,2,4-btc<sup>3−</sup> which adopts a new coordination mode. Moreover, blue fluorescence at 480 nm emission was observed under 320 nm excitation.</p></div
From Antiferromagnetic to Ferromagnetic Interaction in Cyanido-Bridged Fe(III)–Ru(II)–Fe(III) Complexes by Change of the Central Diamagnetic Cyanido-Metal Geometry
<i>Cis</i>- and <i>trans</i>-isomeric heterotrinuclear-metallic
complexes and their two-electron-oxidation products, <i>cis</i>-/<i>trans</i>-[CpÂ(dppe)ÂFeÂ(μ-CN)ÂRuÂ(bpy)<sub>2</sub>(μ-CN)ÂFeÂ(dppe)ÂCp]Â[PF<sub>6</sub>]<sub>2</sub> (<i>cis</i>-/<i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>2</sub>) and <i>cis</i>-/<i>trans</i>-[CpÂ(dppe)ÂFeÂ(μ-CN)ÂRuÂ(bpy)<sub>2</sub>(μ-CN)ÂFeÂ(dppe)ÂCp]Â[PF<sub>6</sub>]<sub>4</sub> (<i>cis</i>-/<i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub>), have been synthesized and structurally characterized.
To the best of our knowledge, the complexes are the first example
of a <i>cis</i>-/<i>trans</i>-isomer with multistates.
Although separated by the diamagnetic cyanido-metal bridge, the two
distant paramagnetic metal centers in both the oxidized complexes
exhibit quite strong magnetic couplings. As a unique example, <i>cis</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub> is antiferromagnetic,
and <i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub> is ferromagnetic. Density functional theory (DFT) calculations suggest
that the spin-delocalization mechanism should be responsible for the
magnetic interactions between the two distant paramagnetic FeÂ(III)
centers across the diamagnetic cyanido-metal in both <i>cis</i>- and <i>trans</i>-<b>1</b><sup>4+</sup>. Most importantly,
the DFT calculations revealed that the type (antiferromagnetic or
ferromagnetic) and strength (<i>J</i>) of the magnetic interactions
in such compounds can be controlled by the variation (<i>cis</i> or <i>trans</i>) of the diamagnetic central metal configurations
From Antiferromagnetic to Ferromagnetic Interaction in Cyanido-Bridged Fe(III)–Ru(II)–Fe(III) Complexes by Change of the Central Diamagnetic Cyanido-Metal Geometry
<i>Cis</i>- and <i>trans</i>-isomeric heterotrinuclear-metallic
complexes and their two-electron-oxidation products, <i>cis</i>-/<i>trans</i>-[CpÂ(dppe)ÂFeÂ(μ-CN)ÂRuÂ(bpy)<sub>2</sub>(μ-CN)ÂFeÂ(dppe)ÂCp]Â[PF<sub>6</sub>]<sub>2</sub> (<i>cis</i>-/<i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>2</sub>) and <i>cis</i>-/<i>trans</i>-[CpÂ(dppe)ÂFeÂ(μ-CN)ÂRuÂ(bpy)<sub>2</sub>(μ-CN)ÂFeÂ(dppe)ÂCp]Â[PF<sub>6</sub>]<sub>4</sub> (<i>cis</i>-/<i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub>), have been synthesized and structurally characterized.
To the best of our knowledge, the complexes are the first example
of a <i>cis</i>-/<i>trans</i>-isomer with multistates.
Although separated by the diamagnetic cyanido-metal bridge, the two
distant paramagnetic metal centers in both the oxidized complexes
exhibit quite strong magnetic couplings. As a unique example, <i>cis</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub> is antiferromagnetic,
and <i>trans</i>-<b>1</b>[PF<sub>6</sub>]<sub>4</sub> is ferromagnetic. Density functional theory (DFT) calculations suggest
that the spin-delocalization mechanism should be responsible for the
magnetic interactions between the two distant paramagnetic FeÂ(III)
centers across the diamagnetic cyanido-metal in both <i>cis</i>- and <i>trans</i>-<b>1</b><sup>4+</sup>. Most importantly,
the DFT calculations revealed that the type (antiferromagnetic or
ferromagnetic) and strength (<i>J</i>) of the magnetic interactions
in such compounds can be controlled by the variation (<i>cis</i> or <i>trans</i>) of the diamagnetic central metal configurations
Characteristics of 400 FSWs at enrolment in the prospective cohort study in Mombasa, Kenya (2006–2007).
<p>IQR inter-quartile range. sd standard deviation.</p>*<p>% (n/N) unless otherwise stated.</p>‡<p>Five participants indicated ‘other’ religion.</p>∧<p>Exchange rate of 500 Kenya Shillings = 4.12 Euro.</p
FSWs' experience of violence from current boyfriend or husband, or any other partners in the 12 months prior to cohort entry and during the 12 months cohort (2006–2007).
<p>FSWs' experience of violence from current boyfriend or husband, or any other partners in the 12 months prior to cohort entry and during the 12 months cohort (2006–2007).</p
Number of partners and sex acts, condom use and age discordance between FSWs and their emotional partners and clients after a 12-month cohort study (2006–2007).
¥<p>Age groups consist of <25 years; 25–34 years; 35–44 years; 45 years and older.</p>§<p>Information was obtained using a 3 month recall period in which female sex worker reported sex with boyfriend(s)/husbands (n = 290), regular clients (n = 266) and casual clients (n = 277).</p>a<p>Poisson regression controlled for multiple measures on the same subject.</p>b<p>Ordinal logistic regression controlled for multiple measures on the same subject.</p
IL-1β overexpression in spinal cord was related to mechanical allodynia in VZV infected rats, and activated astrocytes were the only source of IL-1β.
<p>(A–C′) Double immunofluorescent staining showed that IL-1β-immunoreactivity was localized in GFAP-immunopositive cells but not OX42-immunopositive cells in spinal cord of VZV infected rats. Bars = 20 µm. (D) IL-1β expression was significantly increased in spinal cord of VZV infected rats compared to Naive rats and Mock infected rats. Intrathecal treatment with LAA (astrocytic specific toxin) significantly reduced IL-1β overexpression in VZV infected rats. (E) Using real-time RT-PCR, it was found that the spinal mRNA expression of IL-1β was significantly upregulated in VZV infected rats compared to naive rats and mock infected rats. (F) Intrathecal injection of Pentoxifylline (cytokine inhibitor) or IL-1ra (interleukin-1 receptor antagonist) could significantly attenuated the allodynia. All data were calculated as mean ± SEM (n = 10/group). * <i>P</i><0.05, ** <i>P</i><0.01 vs. Naive rats and Mock infected rats; Δ<i>P</i><0.05 vs. post-infection 2 weeks rats in D and E. * <i>P</i><0.05, ** <i>P</i><0.01 vs. saline (vehicle) treated VZV infected rats in F.</p
Spinal astrocytes were activated in VZV infected rats, which was significantly correlated to mechanical allodynia.
<p>(A–C) Compared with Naive rats and Mock infected rats, GFAP-like immunoreactivity (-LI) in spinal dorsal horn of VZV infected rats was significantly increased. Bar = 200 µm. (D) Real-time RT-PCR showed that spinal mRNA expression of GFAP was significantly upregulated in VZV infected rats compared to naive rats and mock infected rats. (E) With regard to the total number of GFAP positive cells, there was no difference between Naïve rats and VZV infected rats. Bar = 10 µm. (F) Compared to Naive rats and Mock infected rats, Western blot analysis showed that spinal GFAP expression was significantly increased in VZV infected rats. (G) The expression level of GFAP was found to be significantly correlated to the paw withdrawal threshold in VZV infected rats (<i>P</i><0.001, r = −0.868). All data were calculated as mean ± SEM (n = 10/group/week). * <i>P</i><0.05, ** <i>P</i><0.01 vs. Naive rats and Mock infected rats; Δ<i>P</i><0.05 vs. post-infection 2 weeks rats.</p
FSWs reporting inconsistent condom use in past 3 months.
<p>Percentage of FSWs who reported inconsistent condom use in the past 3 months with emotional partners, regular clients and casual clients at 3-monthly visits between May 2006 and September 2007.</p