Light-Assisted Ullmann Coupling of Phenols and Aryl Halides: The Synergetic Effect Between Plasmonic Copper Nanoparticles and Carbon Nanotubes from Various Sources

Utilizing light and plastic wastes as resources to turn the wasted phenols and hazardous aryl halides into value added chemicals seems to be an attractive idea for alleviating the energy crisis and environmental problems. In this work, plasmonic copper nanoparticles (Cu NPs) were loaded onto carbon nanotubes (CNTs) from various sources including commercial CNTs and those derived from plastic wastes. Under visible-light irradiation, the catalyst could efficiently convert phenols and aryl halides to diaryl ethers. Similar with commercial CNTs, excellent activity is also achieved when utilizing CNTs derived from different kinds of plastic wastes as support for the system. Further investigation shows that the visible-light irradiation and light-excited plasmonic Cu NPs are necessary to inhibit the phenol degradation on CNTs and in turn promote the cross-coupling of phenol and aryl halides. Compared with metal oxides and other carbon materials, the excellent capability of CNTs to absorb light, to convert light to heat, and to adsorb both two reactants simultaneously are critical to enhance the activity of Cu NPs, achieving high yields of diaryl ethers. This study could provide a novel strategy for catalyst design and generate a more economically sustainable process.     

Conversion of waste meat to resources by enzymatic reaction under high pressure carbon dioxide conditions

ABSTRACT

Every year, a tremendous amount of meat is wasted, which may have adverse effects on the environment. Therefore, waste meat should be recycled. Building a recycling system for waste meat to reduce financial loss and careful treatment of life-based resources is essential. As meat contains abundant amino acids, it can be used as an immense source of amino acids for other industries following enzymatic hydrolysis. However, during the enzymatic hydrolysis process, the waste meat can easily get contaminated by microbes and therefore needs high temperature. In the present study, we applied high pressure carbon dioxide (HPCD) technology to prevent the contamination of meat by microbes during enzymatic hydrolysis process. According to our research, HPCD has a great potential to be adopted as a novel decontamination technology in the industrial enzymatic hydrolysis process at relatively lower temperature.     

1H NMR based metabolic profiling in Crohn's disease by random forest methodology

The present study was designed to search for metabolic biomarkers and their correlation with serum zinc in Crohn's disease patients. Crohn's disease (CD) is a form of inflammatory bowel disease that may affect any part of the gastrointestinal tract and can be difficult to diagnose using the clinical tests. Thus, introduction of a novel diagnostic method would be a major step towards CD treatment. Proton nuclear magnetic resonance spectroscopy (¹H NMR) was employed for metabolic profiling to find out which metabolites in the serum have meaningful significance in the diagnosis of CD. CD and healthy subjects were correctly classified using random forest methodology. The classification model for the external test set showed a 94% correct classification of CD and healthy subjects. The present study suggests Valine and Isoleucine as differentiating metabolites for CD diagnosis. These metabolites can be used for screening of risky samples at the early stages of CD diagnoses. Moreover, a robust random forest regression model with good prediction outcomes was developed for correlating serum zinc level and metabolite concentrations. The regression model showed the correlation (R²) and root mean square error values of 0.83 and 6.44, respectively. This model suggests valuable clues for understanding the mechanism of zinc deficiency in CD patients. Copyright © 2014 John Wiley & Sons, Ltd.     

Projectile spectator proton production in 84Kr-emulsion interactions at 1.7 A GeV

The multiplicity distribution of projectile protons and multiplicity correlations between black particles, grey particles, shower particles, compound particles, heavily ionized track particles, projectile helium fragments and projectile spectator protons in <'84>Kr-emulsion collisions at 1.7 A GeV are investigated. It is found that the projectile spectator proton multiplicity distribution becomes broader with increasing target mass. The average multiplicity of shower particles and compound particles strongly depends on the number of projectile spectator protons, but the average multiplicity of black particles, grey particles and heavily ionized track particles weakly depends on the number of projectile spectator protons. The average multiplicity of projectile helium fragments increases linearly with increasing numbers of projectile spectator protons. Finally, the multiplicity distribution of projectile spectator protons obeys a KNO type of scaling law.     

In situ generation of palladium nanoparticles using agro waste and their use as catalyst for copper‐, amine‐ and ligand‐free Sonogashira reaction

The use of water extract of waste papaya bark ash for the in situ generation of palladium nanoparticles (Pd NPs) as an efficient and environmentally friendly basic medium for the Sonogashira reaction at room temperature is reported. This methodology follows green chemistry principles as the reaction is performed using agro waste (natural feedstock) for the generation of the Pd NPs as well as for providing a basic medium for the reaction in the absence of any additional organic or inorganic base, ligand and copper salt, giving excellent yield of cross‐coupled product at room temperature. The reaction conditions are compatible with electronically diverse aryl iodides and electronically diverse alkyne derivatives.     

Evaluation and determination of the cyclofructans–amino acid complex binding pattern by electrospray ionization mass spectrometry

The noncovalent complex interactions between cyclofructans, a new class of cyclic oligosaccharide hosts, and various amino acids have been characterized by means of electrospray ionization mass spectrometry and nuclear magnetic resonance. The 1 : 1 stoichiometry of cyclofructans and amino acid complexes was confirmed by their mass‐to‐charge ratio in positive mode. Cyclofructans (CFs)–amino acid complexes and cyclodextrin–amino acid complexes exhibited distinctive different fragment behaviors in collision‐induced dissociation experiments. Coupled with the results of ¹H NMR and nuclear overhauser effect spectroscopy, cyclofructan–amino acid complexes were deduced to be rim complexes via formation hydrogen bonding and ion–dipole forces. The interaction pattern could be controlled by changing the pH condition. In neutral solution, amino acids are located on the positive side of CFs, although moved to the negative side pocket constructed by 3‐OH oxygen of furanose ring and the crown ether oxygen in acid condition. In addition, theory calculation for geometry optimization of Trp and CFs was performed, which was in good agreement with the experimental results. Copyright © 2014 John Wiley & Sons, Ltd.     

Solid‐state 11B and 13C NMR,IR, and X‐ray crystallographic characterization of selected arylboronic acids and their catechol cyclic esters

Nine arylboronic acids, seven arylboronic catechol cyclic esters, and two trimeric arylboronic anhydrides (boroxines) are investigated using ¹¹B solid‐state NMR spectroscopy at three different magnetic field strengths (9.4, 11.7, and 21.1 T). Through the analysis of spectra of static and magic‐angle spinning samples, the ¹¹B electric field gradient and chemical shift tensors are determined. The effects of relaxation anisotropy and nutation field strength on the ¹¹B NMR line shapes are investigated. Infrared spectroscopy was also used to help identify peaks in the NMR spectra as being due to the anhydride form in some of the arylboronic acid samples. Seven new X‐ray crystallographic structures are reported. Calculations of the ¹¹B NMR parameters are performed using cluster model and periodic gauge‐including projector‐augmented wave (GIPAW) density functional theory (DFT) approaches, and the results are compared with the experimental values. Carbon‐13 solid‐state NMR experiments and spectral simulations are applied to determine the chemical shifts of the ipso carbons of the samples. One bond indirect ¹³C‐¹¹B spin‐spin (J) coupling constants are also measured experimentally and compared with calculated values. The ¹¹B/¹⁰B isotope effect on the ¹³C chemical shift of the ipso carbons of arylboronic acids and their catechol esters, as well as residual dipolar coupling, is discussed. Overall, this combined X‐ray, NMR, IR, and computational study provides valuable new insights into the relationship between NMR parameters and the structure of boronic acids and esters. Copyright © 2012 John Wiley & Sons, Ltd.     

Chiral recognition by enantioselective liquid chromatography: Mechanisms and modern chiral stationary phases

An overview of the state-of-the-art in LC enantiomer separation is presented. This tutorial review is mainly focused on mechanisms of chiral recognition and enantiomer distinction of popular chiral selectors and corresponding chiral stationary phases including discussions of thermodynamics, additivity principle of binding increments, site-selective thermodynamics, extrathermodynamic approaches, methods employed for the investigation of dominating intermolecular interactions and complex structures such as spectroscopic methods (IR, NMR), X-ray diffraction and computational methods. Modern chiral stationary phases are discussed with particular focus on those that are commercially available and broadly used. It is attempted to provide the reader with vivid images of molecular recognition mechanisms of selected chiral selector–selectand pairs on basis of solid-state X-ray crystal structures and simulated computer models, respectively. Such snapshot images illustrated in this communication unfortunately cannot account for the molecular dynamics of the real world, but are supposed to be helpful for the understanding. The exploding number of papers about applications of various chiral stationary phases in numerous fields of enantiomer separations is not covered systematically.