Covalent porphyrinic cages (CPCs) have been a target of interest for years. In this paper, we report the design and synthesis of two CPCs in which the cofacial porphyrins have a distance of 7.66 and 11.96 Å via template-directed imine condensation reactions and through the selective choice of templating linker and diamine length.

Highly dispersed bimetallic Ni–Rh nanoparticles with an average diameter of (1.2±0.2) nm were successfully deposited on the metal–organic framework (MOF) ZIF‐8 by using a simple liquid impregnation method. These catalysts were composition dependent toward the dehydrogenation of hydrazine in alkaline solution, whereas Ni66Rh34@ZIF‐8 exhibited the highest catalytic activity among all the catalysts tested with a turnover frequency value of 140 h−1 and 100 % hydrogen selectivity at 50 °C. The excellent catalytic performance may be caused by the synergistic molecular‐scale alloying effect of the bimetallic Ni–Rh nanoparticles on ZIF‐8 and the promotion effect of ZIF‐8. The development of high‐performance catalysts by utilizing MOFs as a novel porous catalyst support to control the limited growth of metal nanoparticles may promote the application of hydrous hydrazine as a promising chemical hydrogen‐storage material and open up new opportunities to use MOF‐supported metal nanoparticles for more applications.

We report a facile liquid impregnation approach for immobilization of ultrafine bimetallic Ni-Pt nanoparticles (NPs) inside the pores of MIL-101. The methods of powder X-ray diffraction, N2 physisorption, X-ray photoelectron spectroscopy, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy were employed to characterize the NiPt@MIL-101 catalysts and further indicated the as-synthesized Ni-Pt NPs were confined in the pores of MIL-101. These as-synthesized bimetallic NiPt@MIL-101 NPs exhibit exceedingly high catalytic activity, selectivity, and durability toward hydrogen generation from alkaline solution of hydrazine.

如今随着生物柴油产业的蓬勃发展,其副产物甘油的再利用也越来越受到关注.文章从甘油酯化、氧化、氢解3个方面概述了甘油催化转化为其它化学品的国内外研究进展,由于篇幅所限,涉及的催化剂体系仅限于有利于工业化的多相催化剂体系.

For the first time, ultrafine Ru nanoparticles with mean diameter of 2 nm are successfully deposited on MIL-96 by using a simple liquid impregnation strategy, and tested for catalytic hydrolysis of ammonia borane. The powder X-ray diffraction, N-2 physical adsorption, transmission electron microscopy, energy-dispersive X-ray spectroscopy and inductively coupled plasma-atomic emission spectroscopy measurements are employed to characterized the Ru/MIL-96 catalysts. Thanks to the unique 3D structure of MIL-96, Ru NPs supported on MIL-96 exhibit much enhanced catalytic activity compared with other commercial supported materials and graphene, with the TOF value of 231 mol H-2 min(-1) (mol Ru)(-1), which is among the highest value ever reported. Moreover, this simple method can be extended to facile synthesis of other MOFs supported monometallic and polymetallic NPs for more application. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

研究了吡咯和邻乙氧基苯胺在水相和有机相中的恒电位化学共聚行为,通过紫外吸收光谱、元素分析和循环伏安测试表征了所得共聚物的组成、电活性及其受电聚合条件的影响,发现在乙腈溶液中,恒电压共聚存在4个阶段,电沉积以2D模式进行;而在水溶液中,电沉积在早期是按2DI模式,后期介于2DI和3DI之间。制备规整的、具有较高电活性的吡咯和邻乙氧基苯胺导电聚合物薄膜,需在酸性水溶液中进行,以聚合电压小于0.7 V的恒电位聚合条件最为理想。

Under the socially economic situation of modern times, as a modern enterprise, capital is not the only source of creating wealth, knowledge can create wealth similarly. In fact, the reliance of enterprises to knowledge workers has gradually exceeded capital. This paper applies person-organization (POF) theory to analyze the managerial puzzles, which find the establishment and maintenance of POF is available to solve knowledge workers’ managerial problems. Meantime, this paper put up with some managerial countermeasures for the establishment and maintenance of POF of knowledge workers through combining their traits.

The induction period of Negishi coupling catalyzed by pincer thioamide-palladium complex 1 was investigated. A heterogeneous mechanism was excluded by kinetic studies and comparison with Negishi coupling reactions promoted by Pd(OAc)(2)/Bu(4)NBr (a palladium-nanoparticle system). Tetramer 2 was isolated from the reaction of 1 and organozinc reagents. Dissociation of complex 2 by PPh(3) was achieved, and the structure of resultant complex 8 was confirmed by X-ray diffraction analysis. A novel alkylated pincer thioimido-Pd(II) complex, 7, generated from catalyst precursor 1 and basic organometallic reagents (RM), was observed by in situ IR, (1)H NMR, and (13)C NMR spectroscopy for the first time. The reaction of 7 with methyl 2-iodobenzoate afforded 74% of the cross-coupled product, methyl 2-methylbenzoate, together with 60% of Pd(II) complex 2. Furthermore, the catalyst, as an electron-rich Pd(II) species, efficiently promoted the Negishi coupling of aryl iodides and alkylzinc reagents without an induction period, even at low temperatures (0 degrees C or -20 degrees C). To evaluate the influence of the catalyst structure upon the induction period, complex 9 was prepared, in which the nBu groups of 1 were displaced by more bulky 1,3,5-trimethylphenyl groups. Trimer 10 was isolated from the reaction of complex 9 and basic organometallic reagents such as CyZnCl or CyMgCl (Cy: cyclohexyl); this is consistent with the result obtained with complex 1. The rate in the induction period of the model reaction catalyzed by 9 was faster than that with 1. Plausible catalytic cycles for the reaction, based upon the experimental results, are discussed.

Two amphiphilic chiral receptors 2a and 2b were designed and synthesized. Both are efficient chiral solvating agents for chiral carboxylic acids. In particular, 2a is an excellent CSA not only for lipophilic guests, but also for some hydrophilic guests. It is the first CSA for the direct determination of the enantiomeric composition of hydrophilic chiral hydroxylated acid in protic polar solvent. (C) 2008 Elsevier Ltd. All rights reserved.

A series of cellulose polyelectrolytes, containing acylamino and carboxyl groups, were homogenously synthesized from cellulose with acrylamide in NaOH/urea aqueous solutions. The structure and solution properties of the polyelectrolytes were characterized with elemental analysis, FTIR, NMR, viscometer and zeta-potential measurement. The nitrogen content and total degree of substituent (DS) of the derivatives increased with increasing of the molar ratio of acrylamide to the anhydroglucose unit (AGU) and the cellulose concentration. The DS of carboxyl groups hardly changed because of the similar reaction and hydrolysis conditions, while the DS of acylamino groups increased with increasing of the total DS values of the products. The polyelectrolytes are soluble in water at a total DS as low as 0.36, and the zeta-potential values in pure water are in the range of −15 to −25 mV. The [η] values of the polyelectrolytes in NaCl aqueous solutions increased apparently with an increase of the pH value in the lower pH region, and reached the maximum value at the pH range from 5 to 6, and while hardly changed at the pH range from 7 to 12. This work provided a facile method for the synthesis of cellulose polyelectrolytes with two different functional groups.

This article abstracts the essential organization influence variable from the variable analysis on the cause influencing the turnover intention of knowledge employees, i.e. the influence of enterprise value on knowledge employees. Meanwhile, basis on the closely relationship between value and POF, it makes a conclusion that the POF can decrease the turnover intention of knowledge employees and designs theoretic hypothesis model. It also proposes outlooks to the further study in future.

New bifunctional organocatalysts amine-thioureas bearing multiple hydrogen bonding donors were synthesized and applied in catalytic asymmetric Michael addition of acetylacetone to aryl and alkyl nitroolefins. Multiple hydrogen bonding donors play a significant role in accelerating reactions, improving yields and enantioselectivities.

Four linear thiourea anion receptors (1-3) derived from simple amino acid have been synthesized and their bonding properties with various chiral N-protected amino acid anions were examined by using UV-vis and fluorescence titration experiments. Receptors 1a, 2, and 3 exhibit excellent enantioselective recognition abilities towards N-Boc-protected alanine anion in the UV-vis spectra, obvious difference in the color of solution indicate that the enantiomers of N-Boc-alanine anion could be distinguished by naked eye directly. Receptor 1a is also found to carry out enantioselective fluorescent recognition of the N-acetyl-glutamate. (1)H NMR experiments suggest that hydrogen-bonding interaction between the host and guest is the main factor in the recognition process.

A novel biodegradable amphiphilic copolymer with hydrophobic poly(C-caprolactone) branches containing cholic acid moiety and a hydrophilic poly(ethylene glycol) chain was synthesized. The copolymer was characterized by FTIR, H-1 NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), polarizing light microscopy (PLM), and wide-angle X-ray diffraction (WAXD) analysis. The amphiphilic copolymer could self-assemble into micelles in an aqueous solution. The critical micelle concentration of the amphiphilic copolymer was determined by fluorescence spectroscopy. A nanoparticle drug delivery system with a regularly spherical shape was prepared with high encapsulation efficiency. The in vitro drug release from the drugloaded polymeric nanoparticles was investigated. Because of the branched structure of the hydrophobic part of the copolymer and the relatively fast degradation rate of the copolymer, an improved release behavior was observed. (c) 2007 Wiley Periodicals, Inc.

Water-insoluble polysaccharide (TM3a), extracted from sclerotia of Pleurotus tuber-regium, was identified as a hyperbranched beta-d-glucan from the results of one- and two-dimensional NMR and GC-MS analysis. The degree of branching of TM3a is 65.5%. TM3a was fractionated by using a non-solvent addition method into 14 fractions, and its solution properties in 0.25 M LiCl/dimethylsulfoxide (DMSO) solution were studied systematically by using static laser light scattering, dynamic light scattering, and viscometry at 25 degrees C. The dependences among the values of intrinsic viscosity ([eta]), radius of gyration (z 1/2), and hydradynamic radius (Rh) on weight-average molecular weight (Mw) were found as the following: [eta] = 0.46Mw0.30+/-0.01, z 1/2 = 4.79 x 10-2Mw0.43+/-0.04, and Rh = 5.01 x 10-2Mw0.41+/-0.02 in the Mw range from 1.94 x 105 to 2.06 x 107 for TM3a in a 0.25 M LiCl/DMSO solution at 25 degrees C. The current theory of polymer solution was applied to explain the relationship among the fractal dimension, ratio of geometric to hydrodynamic radius (rho = z 1/2/Rh), and MwA2/[eta] of TM3a. The results indicated that TM3a existed as a compact chain conformation with a sphere-like structure in LiCl/DMSO solution. Furthermore, by using transmission electron microscopy, we observed directly the spherical molecules with an average diameter of 23.0 +/- 1.8 nm.

Two benzo[de]isoquinoline 1,3-dione amino acids 1 and 2 were readily prepared, and their enantiodiscriminating ability were investigated by H-1 NMR spectroscopy. It was found that 1 exhibited an excellent chiral recognition ability toward chiral alpha-phenylethylamine and some of its derivatives, leading to clear baseline separation of the multiplet of the probe groups in two enantiomers. The stoichiometric ratio and association constants of some host-guest complexes were determined. The interactions between the hosts and guest 3 were further studied by intermolecular NOE experiment and ESI-MS. (c) 2007 Elsevier Ltd. All rights reserved.

行政庇护下的会计师事务所没有生存危机感,缺乏风险和竞争意识,不去主动开辟新的服务领域。

Several acyclic and macrocyclic polyamines were evaluated for their ability to cleave DNA. 1,7-Dimethyl-1,4,7,10-tetraazacyclododecane (DMC) could hydrolyze double-strand DNA at a concentration of 25microM. pH 7.2 was the optimal condition to cleave DNA in the presence of DMC. Supercoiled DNA hydrolytic cleavage by DMC was supported by the evidence from free radical quenching and T4 ligase ligation.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The enantioselectivity of chiral macrocyclic polyamides 1–3 derived from L-/D-tartaric acid was investigated by using 1H NMR. All the macrocycles exhibited certain chiral recognition towards the enantiomers of the racemic carboxylic acids we had chosen. As a chiral solvating agent, the compound 3 has the excellent enantiomeric discriminating ability for mandelic acids and its derivatives, containing an α-OH at the chiral carbon, while the compound 2 has the best enantioselectivity towards dibenzoyltartaric acid. The molar ratio and the association constants of the compound 3 with each of the enantiomers of some guest molecules were determined by using the Job's plots and a nonlinear leastsquares fitting method, respectively. The effect of the structure of the hosts or guests on the enantioselectivity of the compound 1–3 has been explored.