Enzyme-Inspired Chiral Secondary-Phosphine-Oxide Ligand with Dual Noncovalent Interactions for Asymmetric Hydrogenation

Inspired by the unique character of enzymes, we developed novel chiral SPO (secondary-phosphine-oxide) ligand (SPO-Wudaphos) which can enter into both ion pair and H-bond noncovalent interactions. The novel chiral SPO-Wudaphos exhibited excellent results in the asymmetric hydrogenation of α-methylene-γ-keto carboxylic acids, affording the chiral γ-keto acids with up to over 99 % ee. A series of control experiments and DFT calculations were conducted to illustrate the critical roles of both the ion pair and H-bond noncovalent interactions.     

Multiple charge ion beam generation with a 2.45 GHz electron cyclotron resonance ion source

<正>Multiple charge ions (MCIs) are necessary for increasing the output energy of particles in accelerators. In general, MCI beams are largely produced by electron beam ion source (EBIS) [1], laser ion source (LIS) [2], or high-frequency (mostly 5 GHz) electron cyclotron resonance (ECR) ion source [3]. Among these, only ECR ion source can operate in the continuous wave (CW) mode, while EBIS and LIS only support pulses. In addition, ECR ion source with lower frequency (mostly 2.45 GHz) are required primarily for generating single charge state ions, because the corresponding ECR field (875 Gs) is not sufficiently strong for MCI generation [4].     

Computational Studies on the Sc<Subscript>n</Subscript>N<Subscript>m</Subscript> (n + m=10) Clusters: Structure,Electronic and Vibrational Properties

Besides the size and structure, compositions also dramatically affect the properties of clusters. In fact, the increased degree of freedom poses much more challenges to determine the global minimum structure of multi-component clusters. In this thesis, based on the CALYPSO structure searching method, the global minimum structures are obtained for Sc_nN_m (n + m=10) clusters at PW91/6-311+G(d) level. The growth behavior indicates that the cage unit tends to arrange into the compact configurations, and the occupied positions of N atoms shift from the surface towards the center of coordination site with the increasing number of Sc atoms. The relative stabilities have been discussed by analyzing the average binding energies and HOMO–LUMO gaps. In addition, the molecular orbitals, dipole moments, polarizability, hyperpolarizabilities, natural population, natural electron configuration, and Infared and Raman spectra calculations allow complete characterization of the electronic and vibrational properties for the global minimum structural clusters.     

Synthesis of multi‐functionalized carbonyl compounds by palladium–catalysed γ‐substitution of MBH adducts with activated amides

Catalytic allylic γ‐substitution with Morita‐Baylis‐Hillman (MBH) adducts for creating a new family of unsymmetrical dicarbonyl compounds was presented in this work, in which a variety of allylated amide products were achieved in good yields and high regioselectivity with excellent linear‐to‐branched ratios. Especially, it was found that the Pd/HZNU‐Phos complex exhibited remarkably high activity (with a TON up to 16800) in this transformation between dicarbonyl amides and MBH adducts. In addition, the possibly multisite interaction between multifunctional Pd/HZNU‐Phos catalyst system and substrates might responsible for its exceptionally high efficiency in this reaction.     

Reduced graphene oxide-encapsulated mesoporous silica as sulfur host for lithium–sulfur battery

Journal of Solid State Electrochemistry - With up to fivefold higher in energy density vs. lithium-ion battery, lithium–sulfur (Li–S) battery is a compelling energy storage system,...     

The designing strategies of graphene-based peroxidase mimetic materials

Natural enzymes have been praised highly as ideal catalysts, presumably owing to their remarkable advantages of high efficiency, high selectivity, and mild reaction conditions. The reports of chemical simulation and systematic synthesis of natural enzymes such as peroxidase (POD) are rare because of their complex biological structures. POD represents a large family of oxidoreductases and offers a wide range of applications in many fields of science. Recent advance in the fusion of nanomaterial, catalysis, and biochemistry has inspired the development of artificial enzymes implemented with desired catalytic features of natural enzymes. Herein, we review the redox chemistry of POD and compare its catalytic performance to graphene-based nanomaterials (G-NMs) as POD mimetic nanoenzymes bases on catalytic center, binding site, and carrier function. Based on the viewpoints of stereo chemistry and molecular kinetic and dynamics in heterogeneous system, we evaluate and compare the suitability of different NMs as artificial enzyme constituent. We propose that reevaluates design strategies of graphene-based peroxidase (G-POD) mimetic materials and emphasizes on their selectivity (role as catalytic center, binding site, or carrier) is of uttermost.