The reaction of [RuCl2(p-cymene)]2 with 1,3-dialkylimidazolinium salts 1a–f in the presence of a small excess of cesium carbonate yields chelated η6-arene, η1-carbene ruthenium complexes 2a–f. All synthesised compounds were characterized by elemental analysis, NMR spectroscopy. The catalytic activity of RuCl2(η6-arene, η1-imidazolinylidene) complexes 2a–f was evaluated in the direct arylation of 2-phenylpyridine with chlorobenzene derivatives. 相似文献
Like pearls on a string , molecular building blocks have been preorganized and then interlinked on a surface (see STM images). In this way both the supramolecular self‐assembly of the reactants as well as the subsequent thermal activation to release the protecting group are controlled.
In this article we present a new finite algorithm for globally minimizing a concave function over a compact polyhedron. The algorithm combines a branch and bound search with a new process called neighbor generation. It is guaranteed to find an exact, extreme point optimal solution, does not require the objective function to be separable or even analytically defined, requires no nonlinear computations, and requires no determinations of convex envelopes or underestimating functions. Linear programs are solved in the branch and bound search which do not grow in size and differ from one another in only one column of data. Some preliminary computational experience is also presented. 相似文献
Most of the fluorescent pH probes work near neutral or acidic regions of the pH scale. In this work, two different fluorescent Schiff bases, chloro phenyl imino propenyl aniline (CPIPA) and nitro phenyl imino propenyl aniline (NPIPA), have been investigated for pH sensing in the alkaline region. Absorption and emission based spectral data, quantum yield, fluorescence lifetime, photostability and acidity constant (pK(a)) of the Schiff bases were determined in conventional solvents and in PVC. The long wavelength excitable immobilized Schiff bases CPIPA (lambda(ex)=556 nm) and NPIPA (lambda(ex)=570 nm) exhibited absorption and emission based optical response to proton in the pH range of 8.0-12.0 and 7.0-12.0, respectively. Response of the CPIPA was fully reversible within the dynamic working range. The response times were between 3-13 min. A relative signal change of 95% and 96% have been achieved for sensor dyes of CPIPA and NPIPA, respectively. The CPIPA displayed better fluorescence quantum yield (varphi(F)=3.7 x 10(-1)) and higher matrix compatibility compared to NPIPA (varphi(F)=1.6 x 10(-1)) in immobilized PVC. The CPIPA and NPIPA exhibited a slight cross sensitivity to the ions of Hg(+) and Fe(3+), respectively. 相似文献
A voltammetric method using a poly(1‐methylpyrrole) modified glassy carbon electrode was developed for the quantification of adrenaline. The modified electrode exhibited stable and sensitive current responses towards adrenaline. Compared with a bare GCE, the modified electrode exhibits a remarkable shift of the oxidation potentials of adrenaline in the cathodic direction and a drastic enhancement of the anodic current response. The separation between anodic and cathodic peak potentials (ΔEp) for adrenaline is 30 mV in 0.1 M phosphate buffer solution (PBS) at pH 4.0 at modified glassy carbon electrodes. The linear current response was obtained in the range of 7.5 × 10?7 to 2.0 × 10?4 M with a detection limit of 1.68 × 10?7 M for adrenaline by square wave voltammetry. The poly(1‐methypyrrole)/GCE was also effective to simultaneously determine adrenaline, ascorbic acid and uric acid in a mixture and resolved the overlapping anodic peaks of these three species into three well‐defined voltammetric peaks in cyclic voltammetry. The modified electrode has been successfully applied for the determination of adrenaline in pharmaceuticals. The proposed method showed excellent stability and reproducibility. 相似文献
In this research, a new series of thiazoline-iridium (III) complexes ( 4 – 7 ) derived from cysteine were prepared and fully characterized by conventional methods. The molecular structure of complex 5 was also determined by single-crystal X-ray diffraction. These complexes were evaluated as catalysts for hydrogen-borrowing reactions of amines with alcohols. In particular, complex 5 showed the best activity as catalyst. Various amines have been alkylated with alcohols affording moderate to good yield (33–99%). Moreover, the immobilized nanomaterials ( M 1,2 ) were fabricated by sonication process from the best catalyst 5 with the multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO), respectively, and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy, and inductively coupled plasma-mass spectrometry (ICP-MS). The M 1,2 nanomaterials were also tested as catalysts in model catalytic reaction for N-alkylation. The M 1 nanomaterial showed significantly higher activity than the M 2 nanomaterial. The M 1 catalyst was recovered by filtration and reused for four catalytic cycles with high conversion (99%, 97%, 96%, and 86%). 相似文献
Azole derivatives(3,6) obtained starting from 1-(2-methoxyphenyl) piperazine were converted to the corresponding Mannich bases containing β-lactame or flouroquinolone core via a one pot three component reaction.The synthesis of conazole analogues was carried out starting from triazoles by three steps.Reactions were carried out under conventional and microwave mediated conditions.All the newly synthesized compounds were screened for their antimicrobial,enzyme inhibition and antioxidant activity,and most of them displayed good-moderate activity.Binding affinities and non-covalent interactions between enzyme-ligand complexes were predicted with molecular docking method at molecular level.Docking results complemented well the experimental results on α-glucosidase and urease inhibitory effects of the compounds.Higher binding affinities and much more interaction networks were observed for active compounds in contrary to inactive ones.It was predicted with the docking studies that triazole and anisole moieties in the structure of the synthesized compounds contributed to the stabilization of corresponding enzymes through noncovalent interactions. 相似文献
The double emulsion technology has a potential effect on the development of diversity and quality of functional foods by means of decreasing oil or salt concentration, encapsulating and controlling release of valuable components. In this study, it was aimed to formulate stable double emulsions to be used in food systems. W1/O ratios of primary emulsions, stabilized by polyglycerol polyricinoleate (PGPR), were designed as 2:8 and 4:6, and (W1/O)/W2 ratios of the double emulsions were used as 2:8 and 4:6. W/O/W phase ratios, homogenization methods applied to primary emulsion (high-speed homogenization, ultrasonic homogenization), and emulsifier types used in W2 phase [sodium caseinate (SC), xanthan gum, lecithin-whey protein concentrate] were used as independent variables. Particle size and distributions, stability, encapsulation efficiency (EE), rheological properties, long-term stability, and morphological properties of the double emulsions were investigated.The double emulsions prepared with SC and (W1/O)/W2 ratio of 4:6, were found to have the higher stability values, higher apparent viscosity, and lower particle size. High-speed homogenization applied to primary emulsion reduced particle size of the double emulsion and increased apparent viscosity, but did not affect stability and EE of the double emulsions, significantly. 相似文献
In this study, new rhodium(I) complexes (5 and 6) have been prepared by the reaction of [RhCl(COD)]2 with a series of imidazolium salts (3 and 4), which were obtained from a chiral amino alcohol. The catalytic activities of these complexes were tested in the arylation of aldehydes. It was found that the synthesized rhodium complexes were highly effective catalysts for the arylation of aldehydes in short reaction times (5 min, TOF = 1193 h−1). However, the obtained ee values (up to 32% ee) remained low. We have proposed a mechanism for the arylation reaction of aldehydes, which is confirmed via 19F NMR spectroscopy. 相似文献