Department of Chemistry and Material Sciences

The thermal, electrochemical and photochemical conversion of CO₂mediated by ionic liquids is systematically reviewed.

Covering: up to January, 2014. We focus here on β-amino acids as components of complex natural products because the presence of β-amino acids produces structural diversity in natural products and provides characteristic architectures beyond those of ordinary α-L-amino acids, thus generating significant and unique biological functions in nature. In this review, we first survey the known bioactive β-amino acid-containing natural products including nonribosomal peptides, macrolactam polyketides, and nucleoside-β-amino acid hybrids. Next, the biosynthetic enzymes that form β-amino acids from α-amino acids and the de novo synthesis of β-amino acids are summarized. Then, the mechanisms of β-amino acid incorporation into natural products are reviewed. Because it is anticipated that the rational swapping of the β-amino acid moieties with various side chains and stereochemistries by biosynthetic engineering should lead to the creation of novel architectures and bioactive compounds, the accumulation of knowledge regarding β-amino acid-containing natural product biosynthetic machinery could have a significant impact in this field. In addition, genome mining of characteristic β-amino acid biosynthetic genes and unique β-amino acid incorporation machinery could lead to the discovery of new β-amino acid-containing natural products.

Deep eutectic solvents (DESs) are one type of green solvents. Most of the DESs could absorb water from air. However, even a trace amount of water can affect the chemical structure and physical properties of DESs. To date, no study has been reported on the hygroscopicity of DESs. Consequently, in this study, a comprehensive investigation was performed on the capacity, kinetics, mechanism, and furthermore the dynamic process (by PCMW2D-COS IR spectra) of atmospheric water absorption from air by DESs. The results show that most DESs are highly hygroscopic. Surface absorption enhances the overall water absorption capacity by DESs in spite of decreasing the initial water absorption rate. In the beginning, the water absorption increases with an increase in the number of hydrophilic groups in DESs due to the retained DES nanostructure during this period. Therefore, DESs with more hydrophilic groups (ChCl:glucose than ChCl:xylitol) possess a higher water absorption initial rate. However, when the water absorption capacity is high, the hindrance from the H-bond strength from inner DESs needs to be overcome for the absorption of more water. In this case, DESs with stronger H-bonds (ChCl:glucose than ChCl:xylitol) have a lower steady-state water absorption capacity and an easier equilibrium.

Central-to-axial chirality conversion provides efficient access to axially chiral compounds, and several examples regarding the conversion of one, two or four stereocenters to one axis have been reported. Herein, we report the conversion of two stereocenters to one or two chiral axes for the first time. In this study, a new class of enantiomerically enriched 2,3-diarylbenzoindoles was efficiently synthesized using a chiral phosphoric acid-catalyzed [3 + 2] formal cycloaddition and a mild DDQ oxidation strategy. Moreover, a speculative model of the central-to-axial chirality conversion outcome was proposed based on preliminary mechanistic studies and DFT calculations. Potentially, using this strategy, useful chiral phosphine ligand can be synthesized smoothly (99% ee).

with acetone in the solid state would allow a solvent inclusion/release mode, which is an important structural factor for the unprecedented multicolor mechanochromic luminescence.

We reported a reactive probe for HSO3(-), which showed a colorimetric and ratiometric fluorescence response to HSO3(-) with fast response (t1/2 = 20 s), good specificity and low detection limit (3.0 nM). The probe was cell membrane permeable and successfully used for visualizing trace SO2 derivatives in living cells.

Organic electrode materials are promising next-generation battery materials. Combining them with a solid-state electrolyte, and fabricating the materials using atomic/molecular layer deposition provides us a unique platform to study the interactions.

Intermetallic Pd3Pb supported on Al2O3 can act as a highly efficient heterogeneous catalyst for the oxidation of various amines including primary, secondary, aromatic, aliphatic, and cyclic amines.

Bismuth subgallate has been used in wound and gastrointestinal therapy for over a century. The combination of continuous rotation electron diffraction and sample cooling finally revealed its structure as a coordination polymer. The structure provides insight regarding its formula, poor solubility, acid resistance and previously unreported gas sorption properties.

The quantum tunnelling of magnetization was observed in [Zn₂Dy₂], contrarily it was quenched in [Mn₂Dy₂] and [Co₂Dy₂] by spin–spin exchange.

A novel free-standing 3D SnS@PPy-NB/CNT paper electrode with superior Li-ion storage performance is synthesized using a combined <italic>in situ</italic> polymerization restriction/bottom-up assembling technique.

Density functional theory (DFT) based computational electrochemistry has the potential to serve as a tool with predictive power in the rational development and screening of electrocatalysts for renewable energy technologies. It is, however, of paramount importance that simulations are conducted rigorously at a level of theory that is sufficiently accurate in order to obtain physicochemically sensible results. Herein, we present a comparative study of the performance of the static climbing image nudged elastic band method (CI-NEB) vs. DFT based constrained molecular dynamics simulations with thermodynamic integration in estimating activation and reaction (free) energies of the Volmer-Heyrovský mechanism on a nitrogen doped carbon nanotube. Due to cancellation of errors within the CI-NEB calculations, static and dynamic activation barriers are observed to be surprisingly similar, while a substantial decrease in reaction energies is seen upon incorporation of solvent dynamics. This finding is attributed to two competing effects; (1) solvent reorganization that stabilizes the transition and, in particular, the product states with respect to the reactant state and (2) destabilizing entropic contributions due to solvent fluctuations. Our results highlight the importance of explicitly sampling the interfacial solvent dynamics when studying hydrogen evolution at solid-liquid interfaces.

A new dual-curing, solvent-free process is described for the preparation of tailor-made materials from offstoichiometric amine–acrylate formulations.

Cobalt catalysts have evolved to be seen as versatile eco-compatible and economical catalysts in organic synthesis in recent years. Cobalt-catalyzed reactions are undoubtedly a classic in synthetic chemistry for the formation of carbon–carbon and carbon–heteroatom bonds. Another important aspect in this field is catalyst variants, such as low-valent and high-valent cobalt catalysts. This review summarizes the recent progress and synthetic utility of low-valent and high-valent cobalt catalysts towards C–H functionalization processes achieving C–C, C–O, C–N and C–B bond formation. Mechanistic insight is also discussed, with the goal of serving as a stepping stone for further development in this field. In addition, Csp³–H bond functionalization reactions provide many opportunities for novel synthesis approaches.<break/>1 Introduction<break/>2 Carbon–Carbon Bond Formation 2.1 Csp²–Csp³ Bond Formation 2.2 Csp²–Csp² Bond Formation 3 Carbon–Nitrogen Bond Formation 4 Csp³–H Bond Functionalization 5 Carbon–Oxygen Bond Formation 6 Carbon–Boron Bond Formation 7 Conclusion

An organic-ligand-free cuprous iodide trinuclear cluster with significant temperature-dependent structural distortion has been synthesized and characterized, which shows thermochromic luminescence originating from a single cluster-centered triplet due to the absence of an organic ligand. This compound also shows interesting reversible temperature dependent phase transition from chiral to centrosymmetric space groups.

Herein, we effectively modulate the electronic structure of Co₃Fe layered double hydroxides (LDHs) by F-doping using a CHF₃-plasma etching technique.

catalyst. The results of this systematical study aims to serve as guidance for experimentalists by suggesting feasible edge/S-coverage combinations, the synthesis of which would potentially yield the most optimally performing HER-catalysts.

O-DABCO composite system, Knoevenagel condensation reactions proceeded smoothly and cleanly, and the corresponding Knoevenagel condensation products were obtained in good to excellent yields in all cases examined. This protocol provides a versatile solvent-catalyst system, which has notable advantages such as being eco-friendly, ease of work-up and convenient reuse of the ionic liquid.

Abstract The magnetic structure of a 55 mol% FeO–45 mol% P 2 O 5 semiconducting glass containing various relative concentrations of Fe 3+ and Fe 2+ has been studied by ESR techniques over the temperature range −190 to 300 °C. It was determined that the iron ions in the glass matrix are antiferromagnetically coupled in Fe 3+ –Fe 2+ ion pairs. The isolated Fe 3+ −Fe 2+ ion pairs. The isolated Fe 3+ ions were found to be in orthorhombic crystalline fields with λ = 1/3 and 0.23 &lt; D &lt; 0.8 cm −1 , where D and λ are constants in the spin Hamiltonian. Heat treatment of the glass samples caused precipitation of Fe 3+ ‐rich crystalline phases, and it was determined that the Fe 3+ ions in these phases were antiferromagnetically aligned.

Photon-upconversion materials are capable of converting low energy infrared light into higher energy visible or ultraviolet light.