Direct Measurement of Dissolved Gas Using a Tapered Single-Mode Silica Fiber.

Dissolved gases in the aquatic environment are critical to understanding the population of aquatic organisms and the ocean. Currently, laser absorption techniques based on membrane separation technology have made great strides in dissolved gas detection. However, the prolonged water-gas separation time of permeable membranes remains a key obstacle to the efficiency of dissolved gas analysis. To mitigate these limitations, we demonstrated direct measurement of dissolved gas using the evanescent-wave absorption spectroscopy of a tapered silica micro-fiber. It enhanced the analysis efficiency of dissolved gases without water-gas separation or sample preparation. The feasibility of this sensor for direct measurement of dissolved gases was verified by taking the detection of dissolved ammonia as an example. With a sensing length of 5 mm and a consumption of ~50 µL, this sensor achieves a system response time of ~11 min and a minimum detection limit (MDL) of 0.015%. Possible strategies are discussed for further performance improvement in in-situ applications requiring fast and highly sensitive dissolved gas sensing.

Boosting the Electrochemical Performance of Primary and Secondary Lithium Batteries with Mn-Doped All-Fluoride Cathodes.

Transition metal fluorides are potentially high specific energy cathode materials of next-generation lithium batteries, and strategies to address their low conductivity typically involve a large amount of carbon coating, which reduces the specific energy of the electrode. In this study, MnyFe1-yF3@CFx was generated by the all-fluoride strategy, converting most of the carbon in MnyFe1-yF3@C into electrochemical active CFx through a controllable NF3 gas phase fluorination method, while still retaining a tightly bound graphite layer to provide initial conductivity, which greatly improved the energy density of the composite. This synergistic effect of nonfluorinated residual carbon (∼11%) and Mn doping ensures the electrochemical kinetics of the composite. The loading mass of the active substance had been increased to 86%. The theoretical and actual discharge capacity of MnyFe1-yF3@CFx composite was up to 765 mAh g-1 (pure FeF3 is 712 mAh g-1) and 728 mAh g-1, respectively. The discharge capacity at the high-voltage (3.0 V) platform was more than three times higher than that of the non-Mn-doped composite (FeF3@CFx).

Microfluidic static droplet generated quantum dot arrays as color conversion layers for full-color micro-LED displays.

This paper presents an easy and intact process based on microfluidics static droplet array (SDA) technology to fabricate quantum dot (QD) arrays for full-color micro-LED displays. A minimal sub-pixel size of 20 µm was achieved, and the fluorescence-converted red and green arrays provide good light uniformity of 98.58% and 98.72%, respectively.

Micropore filling fabrication of high resolution patterned PQDs with a pixel size less than 5 µm.

PQDs are promising color converters for micro-LED applications. Here we report the micropore filling fabrication of high resolution patterned PQDs with a pixel size of 2 µm using a template with SU8 micropores.

Flexible Quantum-Dot Color-Conversion Layer Based on Microfluidics for Full-Color Micro-LEDs.

In this article, red and green perovskite quantum dots are incorporated into the pixels of a flexible color-conversion layer assembly using microfluidics. The flexible color-conversion layer is then integrated with a blue micro-LED to realize a full-color display with a pixel pitch of 200 µm. Perovskite quantum dots feature a high quantum yield, a tunable wavelength, and high stability. The flexible color-conversion layer using perovskite quantum dots shows good luminous and display performance under different bending conditions; is easy to manufacture, economical, and applicable; and has important potential applications in the development of flexible micro-displays.

Effects of TiO2 crystal structure on the luminescence quenching of [Ru(bpy)2(dppz)]2+-intercalated into DNA.

The intercalation of [Ru(bpy)2(dppz)]2+ labeled as Ru(II) (bpy=2,2'-bipyridine and dppz=dipyrido[3,2,-a:2',3'-c]phenazine) into herring sperm DNA leads to the formation of emissive Ru(II)-DNA dyads, which can be quenched by TiO2 nanoparticles (NPs) and sol-gel silica matrices at heterogeneous interfaces. The calcinations temperature exhibits a remarkable influence on the luminescence quenching of the Ru(II)-DNA dyads by TiO2 NPs. With increasing calcinations temperature in the range from 200 to 850°C, the anatase-to-rutile TiO2 crystal structure transformation increases the average particle size and hydrodynamic diameter of TiO2 and DNA@TiO2. The anatase TiO2 has the stronger ability to unbind the Ru(II)-DNA dyads than the rutile TiO2 at room temperature. The TiO2 NPs and sol-gel silica matrices can quench the luminescence of the Ru(II) complex intercalated into DNA by selectively capturing the negatively DNA and positively charged Ru(II) complex to unbind the dyads, respectively. This present results provide new insights into the luminescence quenching and competitive binding of dye-labeled DNA dyads by inorganic NPs.

Short communication: possible mechanism for inhibiting the formation of polymers originated from 5-hydroxymethyl-2-furaldehyde by sulfite groups in the dairy thermal process.

5-Hydroxymethyl-2-furaldehyde can undergo polymerization to form high-molecular weight molecules via the Maillard reaction during dairy thermal treatment. In this study, the effect of sulfite group on polymer formation, especially in inhibiting the formation of high-molecular weight polymers has been described. Results showed that the sulfite group significantly inhibited the increase of polymer molecular weight via prevention of the polymerization of 5-hydroxymethyl-2-furaldehyde. The formation of an intermolecular dimer based on the glucose molecule through Schiff base cyclization can lead to a competitive reaction with 1,2-enolization to reduce 5-hydroxymethyl-2-furaldehyde formation, which might be another factor in reducing the formation of high-molecular weight polymers.

Poly[diaqua-bis-(µ(3)-1H-imidazole-4,5-dicarboxyl-ato)(µ(2)-sulfato)-diytterbium(III)].

In the title compound, [Yb(2)(C(5)H(2)N(2)O(4))(2)(SO(4))(H(2)O)(2)](n), the Yb(III) ion is eight-coordinated by four O atoms and one N atom from three imidazole-4,5-dicarboxyl-ate ligands, two O atoms from one SO(4) (2-) anion (site symmetry 2), as well as one O atom of a water mol-ecule, giving a bicapped trigonal-prismatic coordination geometry. The metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate and sulfate ligands, generating a heterometallic layer. The layers are stacked along the a axis via N-H⋯O, O-H⋯O, and C-H⋯O hydrogen-bonding inter-actions, generating a three-dimensional framework.

Poly[[tetra-aqua-bis-(µ(3)-imidazole-4,5-dicarboxyl-ato)tetra-kis-(µ(2)-imidazole-4,5-dicarboxyl-ato)tricobalt(II)dilutetium(III)] dihydrate].

In the title compound, {[Co(3)Lu(2)(C(5)H(2)N(2)O(4))(6)(H(2)O)(4)]·2H(2)O}(n), the Lu(III) ions are seven-coordinated in a monocapped trigonal prismatic coordination geometry by six O atoms from three imidazole-4,5-dicarboxyl-ate ligands and one water O atom. The Co(II) ions are six-coordinated in a slightly distorted octa-hedral geometry and exhibit two types of coordination environments. One Co(II) ion, located on an inversion center, is coordinated by two water O atoms as well as two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands. The other Co(II) ion is bonded to four O atoms and two N atoms from four imidazole-4,5-dicarboxyl-ate ligands. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate ligands, generating a three-dimensional network. The crystal structure is further stabilized by N-H⋯O, O-H⋯O, and C-H⋯O hydrogen-bonding inter-actions between the water mol-ecules and the imidazole-4,5-dicarboxyl-ate ligands.

Poly[[tetra-aqua-(µ(4)-imidazole-4,5-dicarboxyl-ato)(µ(3)-imidazole-4,5-dicarboxyl-ato)-µ(3)-sulfato-µ(2)-sulfato-cobalt(II)digadolinium(III)] monohydrate].

The asymmetric unit of the title compound, {[CoGd(2)(C(5)H(2)N(2)O(4))(2)(SO(4))(2)(H(2)O)(4)]·H(2)O}(n), contains one Co(II) ion, two Gd(III) ions, two imidazole-4,5-dicarboxyl-ate ligands, two SO(4) (2-) anions, four coordinated water mol-ecules and one uncoordinated water mol-ecule. The Co(II) ion is six-coordinated by two O atoms from two coordinated water mol-ecules, as well as two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands, giving a slightly distorted octa-hedral geometry. Both Gd(III) ions are eight-coordinated in a distorted bicapped trigonal-prismatic geometry. One Gd(III) ion is coordinated by four O atoms from two imidazole-4,5-dicarboxyl-ate ligands, three O atoms from three SO(4) (2-) anions and a water O atom; the other Gd(III) ion is bonded to five O atoms from three imidazole-4,5-dicarboxyl-ate ligands, two O atoms from two SO(4) (2-) anions as well as a water O atom. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate and sulfate ligands, generating a heterometallic layer parallel to the ac plane. The layers are stacked along the b axis via N-H⋯O, O-H⋯O, and C-H⋯O hydrogen-bonding inter-actions, generating a three-dimensional framework.

Poly[[(µ(2)-acetato-κO,O':O')aqua-bis-(µ(3)-isonicotinato-κO:O':N)samarium(III)silver(I)] perchlorate].

The title compound, {[AgSm(C(6)H(4)NO(2))(2)(CH(3)CO(2))(H(2)O)]ClO(4)}(n), is a three-dimensional heterobimetallic complex constructed from a repeating dimeric unit. Only half of the dimeric moiety is found in the asymmetric unit; the unit cell is completed by crystallographic inversion symmetry. The Sm(III) ion is eight-coordinated by four O atoms of four different isonicotinate ligands, three O atoms of two different acetate ligands, and one O atom of a water mol-ecule. The two-coordinate Ag(I) ion is bonded to two N atoms of two different isonicotinate anions, thereby connecting the disamarium units. In addition, the isonicotinate ligands also act as bridging ligands, generating a three-dimensional network. The coordinated water mol-ecules link the carboxyl-ate group and acetate ligands by O-H⋯O hydrogen bonding. Another O-H⋯O hydrogen bond is observed in the crystal structure. The perchlorate ion is disordered over two sites with site-occupancy factors of 0.560 (11) and 0.440 (11), whereas the methyl group of the acetate ligand is disordered over two sites with site-occupancy factors of 0.53 (5) and 0.47 (5).

Poly[tetra-deca-aqua-tetra-kis-(µ(3)-1H-imidazole-4,5-dicarboxyl-ato)tetra-µ(3)-sulfato-cobalt(II)hexa-gadolinium(III)].

The asymmetric unit of the title compound, [CoGd(6)(C(5)H(2)N(2)O(4))(4)(SO(4))(6)(H(2)O)(14)](n), contains a Co(II) ion (site symmetry [Formula: see text]), three Gd(III) ions, two imidazole-4,5-dicarboxyl-ate ligands, three SO(4) (2-) anions, and seven coordinated water mol-ecules. The Co(II) ion is six-coordinated by two O atoms from water mol-ecules, two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands, giving a slightly distorted octa-hedral geometry. The Gd(III) ions exhibit three types of coordination environments. One Gd ion is eight-coordinated in a bicapped trigonal-prismatic geometry by four O atoms from two imidazole-4,5-dicarboxyl-ate ligands, two O atoms from two SO(4) (2-) anions and two coordinated water mol-ecules. The other Gd ions are nine-coordinated in a tricapped trigonal-prismatic geometry; one of these Gd ions is bonded to four O atoms from two imidazole-4,5-dicarboxyl-ate ligands, three O atoms from three SO(4) (2-) anions and two water O atoms and the other Gd ion is coordinated by one O atom and one N atom from one imidazole-4, 5-dicarboxyl-ate ligand, five O atoms from three SO(4) (2-) anions as well as two coordinated water mol-ecules. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate and sulfate ligands, generating a three-dimensional network. The crystal structure is further stabilized by N-H⋯O, O-H⋯O, and C-H⋯O hydrogen-bonding inter-actions between water mol-ecules, SO(4) (2-) anions, and imidazole-4,5-dicarboxyl-ate ligands.

Poly[[tetra-aqua-bis-(µ(3)-1H-imidazole-4,5-dicarboxyl-ato)tetra-kis-(µ(2)-1H-imidazole-4,5-dicarboxyl-ato)tricobalt(II)diytterbium(III)] dihydrate].

The asymmetric unit of the title compound, {[Co(3)Yb(2)(C(5)H(2)N(2)O(4))(6)(H(2)O)(4)]·2H(2)O}(n), contains one Yb(III) ion, two Co(II) ions (one situated on an inversion centre), three imidazole-4,5-dicarboxyl-ate ligands, two coordinated water mol-ecules and one uncoordinated water mol-ecule. The Yb(III) ion is seven-coordinated, in a monocapped trigonal prismatic coordination geometry, by six O atoms from three imidazole-4,5-dicarboxyl-ate ligands and one water O atom. Both Co(II) ions are six-coordinated in a slightly distorted octa-hedral geometry. The Co(II) ion that is located on an inversion center is coordinated by two O atoms from two water mol-ecules, as well as two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands. The second Co(II) ion is bonded to four O atoms and two N atoms from four imidazole-4,5-dicarboxyl-ate ligands. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl-ate ligands, generating a three-dimensional network. The crystal structure is further stabilized by N-H⋯O, O-H⋯O and C-H⋯O hydrogen-bonding inter-actions involving the water mol-ecules and the imidazole-4,5-dicarboxyl-ate ligands.

Poly[tetra-deca-aqua-tetra-kis-(µ(3)-imidazole-4,5-dicarboxyl-ato)hexa-µ(3)-sulfato-cobalt(II)hexa-samarium(III)].

In the title three-dimensional compound, [CoSm(6)(C(5)H(2)N(2)O(4))(4)(SO(4))(6)(H(2)O)(14)](n), the Co(II) ion is six-coordinated with two O atoms and two N atoms from two imidazole-4,5-dicarboxyl-ate ligands and two coordinated water mol-ecules, giving a slightly distorted octa-hedral geometry. One Sm(III) ion is eight-coordinated in a bicapped trigonal-prismatic coordination geometry by four O atoms from two imidazole-4,5-dicarboxyl-ate ligands, two O atoms from two SO(4) (2-) anions and two coordinated water mol-ecules. The other two Sm(III) ions are nine-coordinated in a tricapped trigonal-prismatic coordination geometry; one of these Sm(III) ions is bonded to four O atoms from two imidazole-4,5-dicarboxyl-ate ligands, three O atoms from three SO(4) (2-) anions and two water O atoms, and the other Sm(III) ion is coordinated by one O atom and one N atom from one imidazole-4,5-dicarboxyl-ate ligand, five O atoms from three SO(4) (2-) anions, as well as two coordinated water mol-ecules. The crystal structure is further stabilized by N-H⋯O, O-H⋯O, and C-H⋯O hydrogen-bonding inter-actions.

Preparative separation of high-purity cordycepin from Cordyceps militaris(L.) Link by high-speed countercurrent chromatography.

A high-speed counter-current chromatography (HSCCC) technique in a preparative scale has been applied to separate and purify cordycepin from the extract of Cordyceps militaris(L.) Link by a one-step separation. A high efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane-n-butanol-methanol-water (23:80:30:155, v/v/v/v) by eluting the lower mobile phase at a flow rate of 2 ml/min under a revolution speed of 850 rpm. HSCCC separation of 216.2 mg crude sample (contained cordycepin at 44.7% purity after 732 cation-exchange resin clean-up) yielded 64.8 mg cordycepin with purity of 98.9% and 91.7% recovery. Identification of the target compound was performed by UV, IR, MS, (1)H NMR and (13)C NMR.

Degradation mechanisms of phoxim in river water.

Degradation of phoxim in river water was fully explored in this paper. Effects of pH, temperature, and photoirradiation on the degradation were investigated in detail. The results indicated that the degradation was characterized by a first-order process; UV irradiation and the increase of pH and temperature substantially accelerated the degradation. To fully characterize the degradation mechanism, HPLC-MS/MS was utilized to identify the degradation intermediates. Five intermediates were identified as phoxom, phoxom dimer, O,O,O',O'-tetraethyldithiopyrophosphate, O,O,O'-triethyl-O'-2-hydroxyethyldisulfinylpyrophosphate, and O,O,O'-triethyl-O'-2-hydroxyethyldithiopyrophosphate. On the basis of the results of the intermediate analysis, the degradation pathways of phoxim under the present experimental conditions were proposed. Through conversion of a thiophosphoryl into a phosphoryl group, some phoxim was converted to phoxom, most of which further formed dimer. Another portion of phoxim transformed to O,O,O',O'-tetraethyldithiopyrophosphate via nucleophilic substitution and photolysis. Thereafter, O,O,O',O'-tetraethyldithiopyrophosphate underwent hydroxylation to form O,O,O'-triethyl-O'-2-hydroxyethyldithiopyrophosphate or sulfur oxidation first and then hydroxylation to produce O,O,O'-triethyl-O'-2-hydroxyethyldisulfinylpyrophosphate. The understanding of phoxim's degradation mechanism in this study will be critical to its safety assessment and increase the understanding of the fate of phoxim in environment water.

Preparative Isolation and Purification of Flavone C-Glycosides from the Leaves of Ficus microcarpa L. f by Medium-Pressure Liquid Chromatography, High-Speed Countercurrent Chromatography, and Preparative Liquid Chromatography.

Combined with medium-pressure liquid chromatography (MPLC) and preparative high-performance liquid chromatography (perp-HPLC), high-speed countercurrent chromatography (HSCCC) was applied for separation and purification of flavone C-glycosides from the crude extract of leaves of Ficus microcarpae L. f. HSCCC separation was performed on a two-phase solvent system composed of methyl tert- butyl ether - ethyl acetate - 1-butanol - acetonitrile - 0.1% aqueous trifluoroacetic acid at a volume ratio of 1:3:1:1:5. Partially resolved peak fractions from HSCCC separation were further purified by preparative HPLC. Four well-separated compounds were obtained and their purities were determined by HPLC. The purities of these peaks were 97.28%, 97.20%, 92.23%, and 98.40%.. These peaks were characterized by ESI-MS(n). According to the reference, they were identified as orientin (peak I), isovitexin-3″-O-glucopyranoside (peak II), isovitexin (peak III), and vitexin (peak IV), yielded 1.2 mg, 4.5 mg, 3.3 mg, and 1.8 mg, respectively.

Erratum: Poly[[di-µ(3)-nicotinato-µ(3)-oxalato-samarium(III)silver(I)] dihydrate]. Corrigendum.

The title of the paper by Zhu, Zhao & Yu [Acta Cryst. (2009), E65, m1105] is corrected.[This corrects the article DOI: 10.1107/S1600536809032115.].

Ethyl-enediammonium bis-(3,4-dihy-droxy-benzoate) monohydrate.

In the title compound, C(2)H(10)N(2) (2+)·2C(7)H(5)O(4) (-)·H(2)O, the cation lies on a centre of symmetry. The crystal structure is stabilized by various inter-molecular O-H⋯O and N-H⋯O hydrogen bonds, and by weak π-π stacking inter-actions with centroid-centroid distances between symmetry-related benzene rings ranging from 3.5249 (13) to 3.7566 (14) Å.

Ammonium (E)-3-(4-hy-droxy-3-meth-oxy-phen-yl)prop-2-enoate monohydrate.

In structure of the title compound ammonium ferulate monohydrate, NH(4) (+)·C(10)H(9)O(4) (-)·H(2)O, O-H⋯O and N-H⋯O hydrogen bonds link the ammonium cations, ferulate anions and water mol-ecules into a three-dimensional array. The ferulate anion is approximately planar, with a maximum deviation of 0.307 (2) Å.