Preparation of Copolymer of Salen-crown Ether Complexes and its Catalytic Activation for Molecular Oxygen

A new stable salen Schiff base cobalt and crown ether sodium complex （SalCo-NaB18C6） was prepared through copolymerization. This copolymer complex was applied to catalytic oxidation of hydrocarbon compound with molecular oxygen without reductant, which was shown the higher activity and selectivity for ketone, and reused effectively.

Highly Active New α-Diimine Nickel Catalyst for Polymerization of Ethylene

A new α-diimine ligand 1a, bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2a, {bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene}dibromo- nickel were successfully synthesized, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscope（FTIR）, elemental analysis and X-ray photoelectron spectroscopy（XPS）. α-Diimine ligand 1b, bis[N,N′-（2,6- dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2b, {bis[N,N′-（2,6-dimethyl- phenyl）imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison. The pre-catalyst 2a with sterically bulky, electron-donating group tert-butyl, activated by diethylaluminum chloride （DEAC） and tested in the polymerization of ethylene, was very highly active[2.01×107 g PE/（mol Ni？h？0.1 MPa）] and led to a very highly branched polyethylene（ca. 35―103 branches/1000 C）. The state of the polyethylene obtained varied from plastic, elastomer polymers to the oil-like hyperbranched polymers.

PEG-400 as an efficient reaction medium for the synthesis of 2,4,5-triaryl-1H-imidazoles and 1,2,4,5-tetraaryl-1H-imidazoles

为一个壶的一个有效协议多，把 PEG-400 用作反应媒介的各种各样的 2,4,5-triaryl-1H-imidazoles 和 1,2,4,5-tetraaryl-1H-imidazoles 的部件合成被描述。这个方法有好收益，更少的污染和简单反应条件的优点。

PEG-SO_3H as catalyst for the Beckmann rearrangement and dehydration of oximes

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.

Flow-injection chemiluminescence determination of tryptophan using galangin-potassium permanganate-polyphosphoric acid system

A high sensitive flow-injection chemiluminescence （FI-CL） method for the determination of tryptophan has been developed. The method is based on the chemiluminescence reaction of galangin-potassium permanganate-tryptophan in polyphosphoric acid （PPA） media. Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit （3tr） of 5.0 × 10^-3 μg/mL. The relative standard deviation （RSD） was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan. Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.

TD-DFT Study on the Electronic Spectrum Properties of 2,7′-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives

The structures of 2,7＇-（ethylene）-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7＇-（ethylene）-bis-8-hydroxyqulnoline and its derivatives were optimized by CIS/6-31G（d）. The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory （TD-DFT） by the B3LYP method with the 6-31G（d） basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline.

Synthesis and X-ray Structural Studies of 2-(2-Benzofuroylimino)-3-aryl-4-phenyl-1,3-thiazolines

The synthesis for acyliminothiazolines by treatment of N, N□-substituted thioureas with α-bromoacetophenone under aqueous media was described. 2-（2-Benzofuroylimino）-3-aryl- 4-phenyl-1,3- thiazolines were characterized by infrared, NMR spectroscopy and elemental analysis. The single crystals of compounds 4a and 4b were grown by slow evaporation of 80% ethanol solution at room temperature. Compounds 4a and 4b crystallize in triclinic space group P1 and monoclinic space group P21/c, respectively.

Microwave-prompted Rapid and Efficient Synthesis of Diacyl Thiosemicarbazides and Semicarbazides in Solvent and Catalyst Free Condition

Eighteen 1-aroyl-4-（2-iodobenzoyl）thiosemicarbazides and corresponding semicarbazides were synthesized in excellent yield under microwave irradiation in solvent and catalyst free condition.

Microwave-assisted synthesis,crystal structure and toxicity of L-aspartic acid zinc spiral linear supramolecular polymer

L-aspartic acid zinc was synthesized by a rapid and convenient method in high yield under microwave conditions, and its single crystal structure was analyzed by X-ray diffraction. The structure unit of the title compound is [Zn(L-Asp)(H2O2)]·H2O, Which is a bicyclo-complex forming a spiral linear polymer via coordination bonds. The spiral linear polymers are assembled as a three-dimensional supramolecule by intermolecular hydrogen bonds. The crystal belongs to the orthorhormbic crystal system, P2(1)2(1)2(1) space group, a=0.7830(3)nm, b=0.9369(4)nm, c=11.599(5)nm,α=β=γ=90.00,V=0.8509(6)nm3,Z=4,Dc=1.955g/cm3,F(000)=512,μ=2.289. The toxicity of the title compound is lower than that of glutamic acid zinc and zinc sulfate.

Single-atom cobalt catalysts for chemoselective hydrogenation of nitroarenes to anilines

Single-atomic catalysts(SACs)caught considerable attention due to their unique structural properties,complete exposed active site,and 100%atom utilization efficiency with remarkable catalytic activity.Mesoporous single-atomic cobalt catalyst with Co-N_(4) active sites was synthesized by using nitrogen-doped graphene derived from acrylonitrile.Single-atomic cobalt was observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)in Co@Nx-C-800.Notably,the density functional theory(DFT)calculation and the extended X-ray absorption fine structures(EXAFS)fitting results indicate that the coordination structure of Co-N is four-coordinated.In this work,the practical hydrogenation of nitroarenes to anilines enabled by Co@Nx-C-800 was established with excellent yields and selectivity,which proved its advantages and potential applications.

Density functional theory study on the insertion reaction mechanism of dibromocarbene with formaldehyde

The insertion reaction mechanism of CBr2 with CH3CH2O has been studied by using the B3LYP/6-311G(d) and CCSD(T)/6-311G(d) at single point. The geometries of reactions,transition state and products were completely optimized. All the transition state is verified by the vibrational analysis and the internal re-action coordinate (IRC) calculations. The results show that reaction (1) is the dominant reaction path,which proceeds via two steps: i) two reactants form an intermediate (IM1),which is an exothermal re-action of 8.62 kJ·mol?1 without energy barrier; ii) P1 is obtained via the TS1 and the H-shift,in which the energy barrier is 44.53 kJ·mol?1. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of this reaction in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature ranges from 200 to 1900 K at 1.0 atm,in which the reaction has a bigger spontaneity capability,equi-librium constant (K) and higher rate constant (k).

The hydrogen sulfate recognition properties of azo-salicylaldehyde schiff base receptors

Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors for basic anions and acidic species hydrogen sulfate by different color changes in a water-containing medium. The experiment of Brφnsted acid-base reaction by adding the sodium hy-droxide or perchloric acid revealed that the mechanism of recognition of anions might be deprotona-tion/protonation of the OH fragments by interacting with different anions and that the deprotona-tion/protonation process is fully reversible. The deprotonation/protonation of the receptors is respon-sible for the dramatic color change.

Intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione under the Mitsunobu reaction conditions

3,4-dihydropyrimidine-2-thione (DHPM ) 的自我分子间的 cyclocondensation 反应被报导给在房间温度面对 diethyl azodicarboxylate (死者) 和 triphenylphosphine (TPP ) 包含 DHPM 核心的新奇 tricyclic 结构。

Density functional theory calculation on the C―H bond insertion reaction of dibromocarbene with acetaldehyde

The insertion reaction mechanism of CBr_2 with CH_3CH_O has been studied by using the B3LYP/6-31G(d) method. The geometries of reactions, transition state and products were completely optimized. All the energy of the species was obtained at the CCSD(T)/6-31G(d) level. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that the propionaldehyde (~HP1) is the main product of CH_2 insertion with CH_3CH_O. The calculated results indicated that all the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet CBr_2 not only can insert the C_α-H [reaction I(1)]) but also can react with C_β-H [reaction II(1)]. The statistical thermodynamics and Eyring transition state theory with Wigner correc- tion are used to study the thermodynamic and kinetic characters of I(1) and II(1) in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature rang is 250 to 1750 K and 250 to 1600 K at 1.0 atm for I(1) and II(1) respectively. The rate constant and equilibrium constant are distinct in the range from 250 to 1000 K so that I(1) more easily occurs, while the reactions are not selected in the temperature range of 1000-1600

Copper-Catalyzed Amination of Aryl Halides with Aqueous Ammonia under Mild Conditions

从 CuSO4 在 situ 产生的 Cu (I)????菨 o ?? 鼀?

Density functional theory study of the mechanism of the acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid and mesitoic acid

The mechanisms of the acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid and mesitoic acid have been investigated based on density functional theory calculations at the B3LYP/6-311G (d,p) level. A polarizable continuum model (PCM) has been established in order to evaluate the effects of solvents on these reactions. The results of the calculations indicate that the first step of the acid-catalyzed decarboxylation of the pyrrole-2-carboxylic acid has two possible pathways,that is,the proton of H3O+ attacks either the-carbon atom or the carboxyl oxygen atom. The subsequent process of forming a four-membered ring transition state is the rate-determining step. The activation energies of acid-catalyzed decarboxylation of pyrrole-2-carboxylic acid proceeding via attack at the-carbon atom and the carboxyl oxygen atom are determined to be 194.21 and 210.41 kJ/mol,respectively. The computational results show that both pathways are favored. However,for the reaction of mesitoic acid with H3O+,the reaction barrier for the former pathway is calculated to be 212.15 kJ/mol,whilst the latter pathway has a reaction barrier of 200.45 kJ/mol. Our computational results are consistent with the experimental observations of Mundle and Kluger.

PEG-OSO_3H as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction in PEG-H_2O

Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.

Quantum chemical study on the abstraction reaction of alkylidenegermylene with oxirane and thiirane

The mechanisms of theion reaction of alkylidenegermylene with oxirane and thiirane have been characterized detail in using density functional theory, as well as ab initio method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies were calculated by CCSD(T)/6-311G(d)//B3LYP/6-311G(d,p) method for the involved conformations. The results show that the reaction pathways for both reactions consist of two ways: (1) the reactants can yield bent products (P1; P4) by syn-isomers; (2) the reactants can also yield three-membered products (P2; P5) by anti-isomers, which then further react with oxirane and thiirane to form the ultimate products (P3-1, P3-2; P6). Furthermore, a comparison with alkylidenecarbene, oxirane, and thiirane was done.