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By the batch method, the effects of contact time, pH, ionic strength, initial concentration, temperature on the sorption of Re(VII) and Se(IV) were investigated. Our results illustrated that Re(VII) and Se(IV) sorption was well described by the pseudo-second-order kinetic model, as well as by Freundlich model. This suggests chemical reaction as a rate-controlling step on the surface with 0.51 and 2.24 mg/g maximum sorption capacity at pH 7.0. The pH has little effect on Re(VII) adsorption, While it significantly affects the Se(IV) sorption. The sorption capacity of Re(VII) and Se(IV) decreased with increasing NaCl concentration. And the adsorption processes of Re(VII) and Se(IV) were endothermic spontaneous processes. What's more, our results also show that the sorption of Re(VII) and Se(IV) in clay rock will not interfere with each other under various conditions. Additionally, the adsorption capacity of Se(IV) in clay is significantly increased under acidic conditions when organic acids in the solution, but not influenced under neutral and alkaline conditions. [ABSTRACT FROM AUTHOR]

A highly efficient and effective method for the synthesis of N-unsubstituted 4-aryl-1,2,3-triazoles promoted by Amberlyst-15 is described. The promoter can be recycled and reused up to eight times without any reduction in its catalytic activity. [ABSTRACT FROM AUTHOR]

By employing a chiral bifunctional thiourea-tertiary amine as catalyst, domino Michael-type Friedel-Crafts alkylation/cyclization of β-naphthols with akylidene Meldrum's acids was realized. The reactions afforded various enantioenriched β-arylsplitomicins with good yields (up to 99%) in moderate enantioselectivities (up to 79%). [ABSTRACT FROM AUTHOR]

This paper presents the theoretical studies of the reactions of Cl atoms with CFCHOCH, CFCHOCHF and CFCHOCHF using an ab initio direct dynamics theory. The geometries and vibrational frequencies of the reactants, complexes, transition states and products are calculated at the MP2/6-31+(d,p) level. The minimum energy path is also calculated at same level. The MC-QCISD method is carried out for further refining the energetic information. The rate constants are evaluated with the canonical variational transition state theory (CVT) and CVT with small curvature tunneling contributions in the temperature range 200-1,500 K. The results are in good agreement with experimental values. [ABSTRACT FROM AUTHOR]

The multiple-channel reactions OH + CH3SCH3 → products, CF3 + CH3SCH3 → products, and CH3 + CH3SCH3 → products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6-31+G(d,p) level, and energetic information is further refined by the MC-QCISD (single-point) method. The rate constants for eight reaction channels are calculated by the improved canonical variational transition state theory with small-curvature tunneling contribution over the temperature range 200-3000 K. The total rate constants are in good agreement with the available experimental data and the three-parameter expressions k1 = 4.73 × 10-16T1.89 exp(-662.45/T), k2 = 1.02 × 10-32T6.04 exp(933.36/T), k3 = 3.98 × 10-35T6.60 exp(660.58/T) (in unit of cm3 molecule-1 s-1) over the temperature range of 200-3000 K are given. Our calculations indicate that hydrogen abstraction channels are the major channels and the others are minor channels over the whole temperature range. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [ABSTRACT FROM AUTHOR]

The multiple-channel reactions SiH3 + SiH3CH3 → products and SiH3 + SiH2(CH3)2 → products are investigated by direct dynamics method. The minimum energy path (MEP) is calculated at the MP2/6-31+G(d,p) level, and energetic information is further refined by the MC-QCISD method. The rate constants for individual reaction channels are calculated by the improved canonical variational transition state theory (ICVT) with small-curvature tunneling (SCT) correction over the temperature range of 200–2400 K. The theoretical three-parameter expression k1(T) = 2.39 × 10-23T4.01exp(-2768.72/T) and k2(T) = 9.67 × 10-27T4.92exp(-2165.15/T) (in unit of cm3 molecule-1 s-1) are given. Our calculations indicate that hydrogen abstraction channel from SiH group is the major channel because of the smaller barrier height among eight channels considered. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 [ABSTRACT FROM AUTHOR]

Ullmann-type coupling reactions between aryl halides and N-containing reagents, phenols, and other related nucleophilic agents are very valuable transformations for organic synthesis. Their conventional reaction conditions require high reaction temperatures. We describe here that some amino acids, either as substrates or ligands, can lead Cu-catalyzed C-N, C-O, C-S, and C-C bond formations work at relatively low temperatures. An ortho-substitution effect caused by NHCOR groups is discussed. Applications of these newly developed reactions to heterocycle preparation and asymmetric synthesis are also presented. [ABSTRACT FROM AUTHOR]

The multiple-channel reactions SiH3 + SiH(CH3)3 → products are investigated by direct dynamics method. The minimum energy path (MEP) is calculated at the MP2/6-31+G(d,p) level, and energetic information is further refined by the MC-QCISD (single-point) method. The rate constants for individual reaction channels are calculated by the improved canonical variational transition state theory with small-curvature tunneling correction over the temperature range of 200–2400 K. The theoretical three-parameter expression k(T) = 2.44 × 10-23T3.94 exp(-4309.55/T) cm3/(molecule s) is given. Our calculations indicate that hydrogen abstraction channel R1 from SiH group is the major channel because of the smaller barrier height among five channels considered. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009 [ABSTRACT FROM AUTHOR]

Theoretical investigations are carried out on the title reactions by means of the direct dynamics method. The optimized geometries, frequencies and minimum energy path are obtained at the MP2/6-31 + G(d,p) level, and energetic information is further refined at the MC-QCISD (single-point) level. The rate constants for both reactions are calculated by the improved canonical variational transition state theory with the small-curvature tunneling correction in a wide temperature range 200–3,000 K. The theoretical rate constant is in good agreement with the available experimental data. Furthermore, the effects of different halogen substitution on the rate constants are also discussed. [ABSTRACT FROM AUTHOR]

Abstract  Two new complexes, [Cu(L)2(CH3OH)] · (ClO4)2 (1) and [Cu(L)2(H2O)] · (NO3)2 (2), have been synthesized and their crystal structures have been determined by X-ray analysis, where L = 3-(3,5-bimethylpyrazole-yl)-6-chloro-pyridazine]. The complex 1 crystallizes in the monoclinic, space group C2/c, and the coordination configuration of copper (II) is better described as trigonal pyramidal geometry with four N atoms from L and one Omethanol. The coordination configuration of 2 is quite similar to that of 1 except Owater instead of Omethanol. The intermolecular hydrogen bonds link the repeat units and extend the molecules to multinuclear structures in both compounds. The spectral properties of the title compounds have been studied and discussed. Furthermore, the antibacterial activities of the title compounds have been detected, the results indicate that the ligands and two copper(II) complexes exhibit certain fungicidal activities again several bacteria. Index Abstract  Two new complexes, [Cu(L)2(CH3OH)]·(ClO4)2 (1) and [Cu(L)2(H2O)]·(NO3)2 (2), have been synthesized and their crystal structures have been determined by X-ray analysis, where L= 3-(3,5-bimethylpyrazole-yl)-6-chloro-pyridazine. The intermolecular hydrogen bonds extend the molecules to multinuclear structures in both compounds. [ABSTRACT FROM AUTHOR]

Theoretical investigations are carried out on the reaction multi-channel CH3COCH3 + Cl (R1) and CH3 COCH3 + CH3 (R2) by means of direct dynamics methods. The minimum energy path (MEP) is obtained at the MP2/6-31 + G(d,p) level, and energetic information is further refined at the BMC–CCSD (single-point) level. The rate constants are calculated by the improved canonical variational transition state theory (ICVT) with the small-curvature tunneling (SCT) correction in a wide temperature range 200–3,000 K. The theoretical overall rate constants are in good agreement with the available experimental data and are found to be k 1 = 3.08 × 10−17 T 2.03exp(−32.96/ T) and k 2 = 1.61 × 10−23 T 3.53 exp(−3969.51/ T) cm3molecule−1s−1. [ABSTRACT FROM AUTHOR]

The multiple-channel reactions OH + CH3NHC(O)OCH3 → products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6-311+G(d,p) level, and energetic information is further refined by the BMC-CCSD (single-point) method. The rate constants for every reaction channels, R1, R2, R3, and R4, are calculated by canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200–1000 K. The total rate constants are in good agreement with the available experimental data and the two-parameter expression k(T) = 3.95 × 10-12 exp(15.41/T) cm3 molecule-1 s-1 over the temperature range 200–1000 K is given. Our calculations indicate that hydrogen abstraction channels R1 and R2 are the major channels due to the smaller barrier height among four channels considered, and the other two channels to yield CH3NC(O)OCH3 + H2O and CH3NHC(O)(OH)OCH3 + H2O are minor channels over the whole temperature range. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 [ABSTRACT FROM AUTHOR]

The multiple-channel reactions OH + SiH(CH3)3 → products (R1) and the single-channel reaction OH + Si(CH3)4 → Si(CH3)3CH2 + H2O (R2) have been studied by means of the direct dynamics method at the BMC-CCSD//MP2/6-311+G(2d,2p) level. The optimized geometries, frequencies and minimum energy path are all obtained at the MP2/6-311+G(2d,2p) levels, and energy information is further refined by the BMC-CCSD (single-point) level. The rate constants for every reaction channels are calculated by canonical variational transition states theory (CVT) with small-curvature tunneling (SCT) contributions over the temperature range 200–2,000 K. The theoretical total rate constants are in good agreement with the available experimental data, and the three-parameter expression k 1 = 2.53×10−21 T 3.14 exp(1, 352.86/ T), k 2 = 6.00 × 10−19 T 2.54 exp(−106.11/ T) (in unit of cm3 molecule−1 s−1) over the temperature range 200–2,000 K are given. Our calculations indicate that at the low temperature range, for reaction R1, H-abstraction is favored for the SiH group, while the abstraction from the CH3 group is a minor channel. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWNTs) functionalized with a water-soluble conducting polymer, sulfonated polyaniline (SPAN), were prepared by in situ polymerization of aniline followed by sulfonation with chlorosulfonic acid in an inert solvent and by hydrolysis in water. Electron microscopy, laser Raman spectroscopy, X-ray photoelectron spectroscopy, and UV−vis absorption spectroscopy were employed to characterize the morphology and chemical structure of the resulting product. The results show that the quinonoid structure of SPAN preferentially interacts with the nanotubes and is stabilized by strong − interaction between two components. The structure of MWNTs was not perturbed by the incorporation of SPAN, since the − interaction between MWNTs and SPAN is much weaker in comparison to that of the carbon covalent bond. The SPAN functionalized MWNTs are highly dispersible in water, thus opening new possibilities for their prospective technological applications. [ABSTRACT FROM AUTHOR]

CuI-catalyzed coupling reaction of electron-deficient aryl iodides with aliphatic primary amines occurs at 40 °C under the promotion of N-methylglycine. Using L-proline as the promoter, coupling reaction of aryl iodides or aryl bromides with aliphatic primary amines, aliphatic cyclic secondary amines, or electron-rich primary arylamines proceeds at 60-90 °C; an intramolecular coupling reaction between aryl chloride and primary amine moieties gives indoline at 70 °C; coupling reaction of aryl iodides with indole, pyrrole, carbazole, imidazole, or pyrazole can be carried out at 75-90 °C; and coupling reaction of electron-deficient aryl bromides with imidazole or pyrazole occurs at 60-90 °C to provide the corresponding N-aryl products in good to excellent yields. In addition, N,N-dimethylglycine promotes the coupling reaction of electron-rich aryl bromides with imidazole or pyrazole to afford the corresponding N-aryl imidazoles or pyrazoles at 110 °C. The possible action of amino acids in these coupling reactions is discussed. [ABSTRACT FROM AUTHOR]

The article discusses the use of dialkylpyridine ligands in the palladium (Pd)-catalyzed olefination of electron-deficient arenes. It is proposed that Pd-catalyzed olefination of benzene has been made to improve the efficiency and practicality of the reaction. Moreover, chemical reaction is also associated with the reliability of dialkylpyridine ligands.

We have developed a novel and simple method for chemical reaction synthesis of Eu(OH)3nanorods with a diameter of 20-30 nm and a length of about 300 nm at 90?°C using cyclohexylamine as the alkaline source instead of NaOH with subsequent thermal conversion to Eu2O3nanorods at 700?°C. The effect of different alkaline sources on the shape of Eu(OH)3nanostructures has been investigated. Moreover, the morphology, structure and optical properties of the Eu(OH)3and Eu2O3nanostructures prepared under different conditions have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL). The mechanisms of formation for the synthesis of the Eu(OH)3nanostructures with different morphologies are presented. [ABSTRACT FROM AUTHOR]

The LixZryOz compounds, including pure monoclinic-phase Li2ZrO3, triclinic and monoclinic-phase Li6Zr2O7, high-purity tetragonal-phase Li2ZrO3 and rhombohedral-phase Li8ZrO6 were synthesized by solid-state reaction method. The influences of different reagents, calcination temperature and time on the product of LixZryOz were investigated via X-ray diffraction (XRD), and the properties of CO2 adsorption were also tested by the reactive Thermo-gravimetric (TG) analysis. The results indicated that monoclinic-phase Li2ZrO3 was the main product if Li2CO3 and ZrO2 used as the initial reagents; when Li2CO3 was substituted with LiOH, tetragonal and monoclinic-phase Li2ZrO3, triclinic and monoclinic-phase Li6Zr2O7 could be produced at suitable conditions, respectively; with replacing ZrO2 by Zr(NO3)4, the synthesis time for monoclinic-phase Li6Zr2O7 could be shorten greatly, and high-purity rhombohedral-phase Li8ZrO6 could be produced at enough Li/Zr molar ratio. The CO2 adsorption test indicated that each of the synthesized LixZryOz products has definite CO2 capture capacity. [ABSTRACT FROM AUTHOR]

A highly atom-economic one-pot synthesis of functionalized tetrahydropyridines by a multicomponent condensation reaction of β-keto ester, two equivalents of aromatic aldehyde, and two equivalents of amine in the presence of a catalytic amount of cerium ammonium nitrate (CAN) is reported. In this way, a series of pharmacologically interesting substituted piperidine derivatives were obtained in moderate to good yields at room temperature. [ABSTRACT FROM AUTHOR]

An efficient and metal-free oxidative method was reported for synthesis of triply linked diporphyrins with 2.5 equiv of phenyliodine bis(trifluoroacetate) (PIFA). This reaction showed high selectivity for Zn(II) porphyrins and had been successfully applied in the synthesis of a novel triply−singly interlacedly linked porphyrin array with lower energy gap. [ABSTRACT FROM AUTHOR]

Ultrathin hexagonal SnS2nanosheets are synthesized viaa simple hydrothermal reaction. The nanosheets have been applied as an anode for lithium-ion battery, which shows highly reversible capacity and good cycling stability with excellent capacity retention of 96% after 50 cycles. [ABSTRACT FROM AUTHOR]

An efficient copper-catalyzed synthesis of 3-(trifluoromethyl) pyrrolo[2,1-α]isoquinolines was achieved through a sequential one-pot two-step three-component reaction of a substituted isoquinoline, a terminal aryne, and methyl 4,4,4-trifluorobut-2-ynoate, with air as an oxygen source. This oxidative cyclization proceeds through an initial copper(I)-catalyzed C–H alkynylation to give alkynyl-1,2-dihydroisoquinolines that subsequently undergo a copper(II)-assisted intramolecular cyclization under mild conditions to give the desired products in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

A one-pot two-step three-component process for the synthesis of trifluoromethylated 2-hydroxy-5-oxo-3,4,5,6,7,8-hexahydro- 2H-chromenes has been developed. The three-component reaction of dimedone, substituted benzaldehydes, and methyl 4,4,4-trifluorobut- 2-ynoate gave the desired products in moderate to good yields. Excellent regioselectivity and diastereoselectivity were observed. Furthermore, refluxing the product chromenes with p-toluenesulfonic acid in toluene gave the corresponding dehydrated products - trifluoromethylated 5-oxo-5,6,7,8-tetrahydro-4H-chromenes. [ABSTRACT FROM AUTHOR]

Focuses on the study conducted by Chinese researchers on the synthesization of the new three-dimensional bimetallic tellurite, BaV₂TeO₈, through hydrothermal reaction of Ba(OH)₂, TeO₂ and V₂O₅; Characterization of the synthesization by a single-crystal X-ray diffraction; Composition of the three-dimensional framework with anionic layers parallel to and connected via Ba-O bonds; Attribution of the anionic layers as formed through types of polyhedra such as the VO#x2085; tetragonal pyramids, VO#x2084; tetrahedra, and TeO#x2084;₊#x2082; folded square polyhedra.

The spontaneous self-assembly reactions of 2,3,5,6-tetrafluorobenzenedicarboxylic acid (H2BDC-F4) with Ca(NO3)2·4H2O in different solvents resulted in the generation of hydrophilic 3D chiral and achiral Ca(II)-organic frameworks {[Ca4(BDC-F4)4(H2O)4]·4H2O}n (1) and [Ca(BDC-F4)(MeOH)2]n (2), respectively. Complex 1 exhibits higher water solubility compared to 2, and further dissolution of 1 in water results in a new achiral crystal, [Ca(BDC-F4)(H2O)4]n (3). All complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal and powder X-ray diffraction techniques. Complex 1 crystallizes in the tetragonal P41212 chiral space group and features a rare binodal 5-connected network, directed by a unique 3D chiral (10,3)-a water aggregation consisting of two distinct helical arrays. Complex 2 crystallizes in the space group C2/c and has a binodal 4-connected pts net. Complex 3 crystallizes in the space group P21/m and presents a 2D layer framework containing the unprecedented polymeric [CaII-H2O]n chain based on triple μ2-O aqua bridges. The structural discrepancies illustrate the solvent-induced effect on the construction and structural transformation of chiral and achiral coordination frameworks. Moreover, gas (N2 and CO2) adsorption studies show that the dehydrated framework 1a exhibits excellent selective CO2 gas uptake at 195 K. [ABSTRACT FROM AUTHOR]

The monomer 1 derived from achiral 1-(aminoxy)cyclopropanecarboxylic acid (OAcc) and oligopeptides 2-9 consisting of a chiral α-aminoxy acid and an achiral α-aminoxy acid such as OAcc were synthesized and their structures characterized. The eight-membered-ring intramolecular hydrogen bond, namely the α N-O turn, was formed between adjacent residues independent of their chirality. However, the helix formation was sequence-dependent. Dipeptide 2 bearing chiral α-aminoxy acid (D-OAA) at the N-terminus and achiral OAcc at the C-terminus preferentially adopted a right-handed 1.88 helical structure, but dipeptide 3 (OAcc-D-OAA) did not. Theoretical calculation results, in good agreement with experimental ones, revealed that the biased handedness of α N-O turn found in OAcc residue depends on its preceding chiral residue. It was then found that the helical conformation was destroyed in the case of oligopeptides 6 and 7 [OAA-(OAcc)n, n = 2, 3]. The crystal structure of tripeptide 8 (iPrCO-D-OVal-OAcc-D-OVal-NHiBu) further disclosed the helical structure formed by three consecutive homochiral α N-O turns. This study has uncovered achiral aminoxy acid residues such as the OAcc unit as a useful building block to be incorporated into chiral aminoxy peptides to mimic chiral helix structure. [ABSTRACT FROM AUTHOR]

A novel bis(8-hydroxyquinoline) compound based on formylquinolinol has been synthesized and characterized by X-ray single-crystal diffraction, IR, UV, 1H NMR, MS, and elemental analysis. It is reported that the formylation of 8-hydroxyquinoline gives substitution at the 7-position by X-ray structure analysis. In comparison with the spectrum for 8-hydroxyquinoline, the fluorescence spectrum of this novel bis(8-hydroxyquinoline) species shows a red shift. The optimized geometrical structures of the neutral and cationic states on 2,7‘-ethylenebis(8-hydroxyquinoline) were optimized at the DFT B3LYP/cc-pvdz level. The results are in good agreement with the reference and experimental values. The hole mobility of 2,7‘-ethylenebis(8-hydroxyquinoline) has been predicted by the reorganization energy and electron-transfer coupling matrix elements using quantum mechanics (QM), and the value is 1.612 cm2/(V s). [ABSTRACT FROM AUTHOR]