Synthesis of New Chiral C_2-Symmetrical Bis(oxazoline) Compounds

New chiral C_2-symmetrical bis(oxazoline) compounds bearing one isobutyl-, secbutyl-, benzyl- or isopropyl-substituent at the 4-position have been prepared and characterized.

Crystal Structure, DFT and Electrochemical Property of a Novel C3-symmetrical 1,3,5-Tri（9-ethyl-6-nitrocarbazol-3-yl） Benzene

A novel C3-symmetrical molecule, 1,3,5-tri(9-ethyl-6-nitrocarbazol-3-yl) benzene(IV), was synthesized and characterized by 1 H NMR, 13 C NMR and UV-vis spectroscopy, elemental analyses and X-ray single crystal diffraction analysis. For this complex: C48 H36 N6 O6, Mr = 792.83, triclinic system, space group P1, a = 11.568(6), b = 13.158(7), c = 17.856(10) ?, α = 95.419(9), β = 107.345(8), γ = 114.682(8)o, V = 2281(2) ?3, Z = 2, Dc = 1.154 g/cm3, λ = 0.71073 ?, F(000) = 828, S = 1.083, R = 0.0836 and wR = 0.1926 for 3304 observed reflections with I > 2ζ(I). The compound possesses good thermal stability with the decomposition temperature(Td) of 265 ℃. The absorption and emission spectra show that the compound can emit blue light in CHCl3, and the quantum yield of compound IV in EtOH was 0.66. Furthermore, the electrochemical properties of compound IV were also studied by cyclic voltammetry(CV) method, and the results correspond to the data of theoretical calculation by the Gaussian 09 software.

On Generalized <i>φ</i>-Recurrent Sasakian Manifolds

The object of the present paper is to introduce the notion of generalized φ-recurrent Sasakian manifold and study its various geometric properties with the existence of such notion. Among others we study generalized concircularly φ-recurrent Sasakian manifolds. The existence of generalized φ-recurrent Sasakian manifold is given by a proper example.

(g,e)-Symmetric Rings

Let R be a ring and e,g in E(R),the set of idempotents of R.Then R is called(g,e)-symmetric if abc=0 implies gacbe=0 for any a,b,c∈R.Clearly,R is an e-symmetric ring if and only if R is a(1,e)-symmetric ring;in particular,R is a symmetric ring if and only if R is a(1,1)-symmetric ring.We show that e∈E(R)is left semicentral if and only if R is a(1−e,e)-symmetric ring;in particular,R is an Abel ring if and only if R is a(1−e,e)-symmetric ring for each e∈E(R).We also show that R is(g,e)-symmetric if and only if ge∈E(R),geRge is symmetric,and gxye=gxeye=gxgye for any x,y∈R.Using e-symmetric rings,we construct some new classes of rings.

Dual-Coupled Robust Wireless Power Transfer Based on Parity-Time-symmetric Model

The characteristics of the wireless power transfer(WPT)system vary under different transfer distances.As distance increases,efficiency drops off sharply,limiting the wider use of WPT technology.In order to mitigate this problem,this paper proposes a novel dual-coupled WPT system,where both electric-coupled mechanism and magnetic-coupled mechanism are utilized to enhance the transfer efficiency.Furthermore,a Parity-Time(PT)-symmetric circuit is utilized to realize robustness of the system.The coupled-mode model of the system is established and the expressions of operating frequency,transfer efficiency and output power are deduced.Analysis results indicate that in the unbroken PT-symmetric state,compared with single-coupled systems,the proposed system can keep constant performance within a longer distance;in broken PT-symmetric state,the proposed system has higher transfer efficiency.Simulated results and comparative results are in accordance with the theoretical analysis.Within 1.4m,this scheme can transfer power with constant efficiency of 77%and constant output power of 70W.

Axially Chiral C2-Symmetric N-Heterocyclic Carbene （NHC） Palladium Complex-Catalyzed Asymmetric Fluorination and Amination of Oxindoles

Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.

Chiral Phenol-2NO Ligand Cooperation with Achiral Organic Base in the Zn(II)-Catalyzed Asymmetric Alkylation Reaction of Indoles

The privileged C_(2)-symmetric rigid phenol-type ligand is more attractive but challenging in asymmetric catalysis.Herein,we designed and synthesized a class of rigid-featured chiral tridentate Phenol-2NO ligands,that incorporate the advantages of both the phenol skeleton and pyrroloimidazolone-based N-oxide moiety,from readily available L-prolinamides in operationally simple two steps and up to 44%overall yield.More importantly,using an achiral quinoline derivative as an additive,the newly developed Phenol-2NO ligand could serve as the anioic ligand upon deprotonative activation to coordinate to Zn(II)to form a highly enantioselective catalyst for the asymmetric Michael-type Friedel-Crafts alkylation reaction of indoles with 2,3-dioxopyrrolidines.Excellent yields(up to 90%)and high enantioselectivities(up to 99%ee)are obtained for a wide range of substrates under mild conditions.Experiments and DFT calculations revealed the reaction mechanism and the origins of the enantioselectivity.This also represented the first activation of phenol-type ligand/metal complex by an achiral organic base as the additive in asymmetric catalysis.

（3,3）-Connected Three-dimentional Supramolecular Metal Organic Polyhedral Based on Nanometresized Ligand with Magnetism Properties

A three-dimentinal metal organic framework [Co2（L）CI（DMF）2（H20）]（DMF）3（H20）3 based on the nano- metresized ligand 4,4＇,4＂-[1,3,5-benzenetriyltris（carbonylimino）]trisbenzoic acid was synthesized, and characterized by means of single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetry analysis and magnetism. This obtained structure can be considered to be constructed from 2D layer, which displays the topology of hbc based on Co2（COO）3 secondary building unit, and further to be linked into a 3D suprarnolecular architecture by N--H...O hydrogen bonds. The magnetism of the complex was carried out, which shows ferromag- netic exchange interactions.

The first catalytic asymmetric addition of diethylzinc to aldehyde promoted by chiral thiourea

A series of C_2-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial L-phenylalanine.All of the new compounds have been fully characterized by IR,~1H NMR,^（13）C NMR,MS spectra and elemental analyses.The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc,the corresponding sec-alcohols were gained with excellent enantioselectivities（up to 87.1%ee） and high yields（up to 76.7%） after the conditions were optimized.