Superior Anodic Lithium Storage in Core–Shell Heterostructures Composed of Carbon Nanotubes and Schiff-Base Covalent Organic Frameworks

Covalent organic frameworks(COFs)after undergoing the superlithiation process promise high-capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox-active sites.Herein,integrating carbon nanotubes(CNTs)with imine-linked covalent organic frameworks(COFs)was rationally executed by in-situ Schiff-base condensation between 1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde and 1,4-diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites(CNT@COF).Accordingly,the redox-active shell of COF nanoparticles around one-dimensional conductive CNTs synergistically creates robust three-dimensional hybrid architectures with high specific surface area,thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode.Remarkably,upon the full activation with a superlithiation process,the as-fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g^(−1),which is the highest specific capacity among organic electrode materials reported so far.Meanwhile,the superior rate capability and excellent cycling stability are also obtained.The redox reaction mechanisms for the COF moiety were further revealed by Fourier-transform infrared spectroscopy in conjunction with X-ray photoelectron spectroscopy,involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs.

Schiff-base polymer derived FeCo-N-doped porous carbon flowers as bifunctional oxygen electrocatalyst for long-life rechargeable zinc-air batteries

Rational design and exploration of low-cost and robust bifunctional oxygen electrocatalysts are vitally important for developing high-performance zinc-air batteries(ZABs).Herein,we reported a facile yet cost-efficient approach to construct a bifunctional oxygen reduction reaction(ORR)/oxygen evolution reaction(OER)electrocatalyst composed of N-doped porous carbon nanosheet flowers decorated with Fe Co nanoparticles(Fe Co/N-CF).Rational design of this catalyst is achieved by designing Schiff-base polymer with unique molecular structure via hydrogen bonding of cyanuramide and terephthalaldehyde polycondensate in the presence of metal cations.It exhibits excellent activity and stability for electrocatalysis of ORR/OER,enabling ZAB with a high peak power density of 172 m W cm^(-2)and a large specific capacity of 811 m A h g^(-1)Znat large current.The rechargeable ZAB demonstrates excellent durability for 1000 h with slight voltage decay,far outperforming a couple of precious Pt/Ir-based catalysts.Density functional theory(DFT)calculations reveal that high activity of bimetallic Fe Co stems from enhanced O_(2)and OH-adsorption and accelerated O_(2)dissociation by OAO bond activation.

基于Schiff-base结构化合物载体的汞离子选择性电极的制备与表征

高产率合成了一种新的Schiff-base结构化合物，并将其表征为高选择性聚合物膜汞离子选择性电极载体。考察了不同增塑剂及离子交换剂对膜电极响应性能的影响，在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1．0×10^-6-3．0×10^-4mol／L，响应斜率为（29．3±0．3）mV／dec，检出限为2．6×10^-7mol/L；该电极响应速率快（小于12s），可在较宽的pH范围内（pH2．8～5．6）使用，且其它常见碱金属、碱土金属以及过渡金属离子对该测试电极的干扰小；可准确检测自来水中汞离子的浓度。

手性三齿Schiff-base配体的合成及其催化的不对称Henry反应研究

以L-酪氨酸甲酯盐酸盐为原料,通过格氏反应合成了一种手性β-氨基醇;以水杨醛为原料,通过溴代反应合成了3,5-二溴水杨醛和5-溴水杨醛;将手性β-氨基醇和溴代水杨醛在乙醇中缩合,制备了两种手性三齿Schiff-base配体.产物的结构经IR,1 H NMR,13C NMR和MS表征确定.将配体应用于催化不对称Henry反应中,考察其在不同反应条件下的催化性能,在最优化的反应条件下,不同底物均获得了较好的催化效果,产率最高达95%,ee值最高达90%.

大环化合物(macrocycles)酶模型

对大环化合物的结构特点及催化作用进行了综述。

Synthesis and Crystal Structure of a New Macrocycle Based on Diethoxycarbonyl Glycoluril: C_(26)H_(30)N_6O_(10)

A new macrocycle based on diethoxycarbonyl glycoluril 3,C26H30N6O10,has been synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic,space group P21/c with a = 12.7291（10）,b = 25.157（2）,c = 8.5489（7） A,β = 104.4760（10）°,V = 2650.7（4） A^3,Z = 4,C26H30N6O10,Mr = 586.56,F（000） = 1232,T = 292（2） K,Dc = 1.470 g/cm^3,μ = 0.115 mm^-1,the final R = 0.0590 and wR = 0.1299 for 4918 observed reflections with I 〉 2σ（I）. In the structure of the title compound,a three-dimensional microporous architecture is formed via intermolecular hydrogen bonding interactions.

Density Functional Theory Study on La Complex with Schiff-base as Building Block

Quantum density functional theory （DFT） results are reported for the building block [LaL^1（NO3）] of La complex [LaL^1（NO3）]NO3·5H2O （L^1 = （CH3）2CHCH2CH（NCHC4H3O）COO^-）. The structure was optimized and the calculation results show that the lanthanum ion is coordinated by one nitrogen atom and three oxygen atoms of L^1 and two oxygen atoms of nitrate ion. The bond length of La-N is 0.2637 nm and the average length of La-O is 0.2526 nm, which are consistent with the literatures. In addition, the stabilities, electronic structural characteristics and IR spectra of the complex have been analyzed, which describe the coordination of lanthanum ion with other atoms in detail.

Synthesis,Crystal Structure and Electrochemical Property of the Ferrocenyl Schiff-base (E)-N’(Ferrocene Ethylidene)Picolino Hydrazide

A novel Schiff-base compound based on ferrocene C18H17OFeN3 （1） has been synthesized and characterized by X-ray diffraction. The title compound crystallizes in monoclinic, space group P21/c with a = 19.2343（17）, b = 10.5084（9）, c = 7.9373（7） A, β = 97.7740°, Z = 4, V = 1589.6（2） A^3, Dc = 1.451 g/cm^3, μ（MoKα） = 0.956 mm^-1, F（000） = 720, the final R = 0.0343 and wR = 0.0973 for 2759 observed reflections （I 〉 2σ（I））. Electrochemical measurements exhibit that compound 1 undergoes a reversible one-electron redox process.

Two 3-D Neutral Zn(Ⅱ)-MOFs Generated from the Asymmetric Schiff-base Ligand

Two new Zn（Ⅱ）-MOFs were synthesized based on an asymmetric Schiff-base ligand LH, which is obtained by the condensation of 5-formyl-8-hydroxyquinoline and 3-pyridinecar- boxylic acid hydrazide. In different mixed solvents, we get two new isomorphism compounds, [Zn（L）2]＇CaHsO2-2MeOH （1） and [Zn（L）2]＇CH2CIz＇2MeOH （2）. Compounds 1 and 2 have been characterized by single-crystal X-ray diffraction, elemental analysis and IR. Compound 1 crystallizes in monoclinic, space group P2/c, with a - 13.856（4）, b = 14.156（4）, c = 9.620（3）А, β = 110.167（5）°, V = 1771.3（9） /k3, Dc = 1.500 g/cm3, C3sH3sNsOsZn, Mr = 800.13, F（000） = 832, p（MoKa） = 0.761 mm-1, Z = 2, the final R = 0.0596 and wR = 0.1221 for 2112 observed reflections （I 〉 2σ（0）. Compound 2 belongs to monoclinic, space group P21/c, with a = 13.575（3）, b = 14.130（3）, c = 9.485（2） A, β = 107.908（3）°, V= 1731.2（6） A3, Dc = 1.529 g/cm3, CasH32C12NsO6Zn, Mr = 796.96, F（000） = 820, g（MoKa） = 0.926 mm-1, Z = 2, the final R -- 0.0527 and wR = 0.1395 for 2501 observed reflections （I 〉 2σ-（/））. The Zn（II） centers in both 1 and 2 display a distorted octahedral coordination geometry. The octahedral Zn（lI） nodes and L linkages build up 2-D nets consisting of parallelogram-like grids in the ab plane. The neighboring nets stack through hydrogen bonds to generate 3-D rhombic channels. In 1, the 1,4-dioxane and MeOH guests alternatively arrange in the channels and effectively take up the free space; while in 2, the CH2CI/guests are arranged in the channels. In addition, the encapsulated MeOH molecules are bonded to the framework by hydrogen bonds.

The Rapid Synthesis of Schiff-Base without Solvent under Microwave Irradiation

A microwave-assisted preparation of a series of Schiff-base via efficient condensation of salicylaldehyde and aryl amines without solvent is described in high yield as well as environmental friendship reaction in organic synthesis.

Antioxidant activity of bovine serum albumin binding amino acid Schiff-bases metal complexes

Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin （BSA）, which afforded BSA binding Schiff-base metal complexes （BSA-SalGluM, M=Cu, Co, Ni, Zn）. The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.

Synthesis and Crystal Structure of a Macrocycle[Cu(dadm)(mal)(H_(2)O)]_(2)·2H_(2)O

The reaction of 4,4?-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]22H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2) ? b = 106.75(3)o, V = 1693.5(6) 3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, ?(MoKa) = 0.71073 ? = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and wR = 0.1244 for 3421 observed reflections with I > 2s(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3 ??5.9 ?

Synthesis, Crystal Structure and Characterization of a New Mononuclear Zn(Ⅱ) Complex from Schiff-base Ligand

A new mononuclear [Zn（H-1L）2] （L = 1H-indole-3-ethylene-salicylaldimine） was synthesized through the reaction of Zn（Ac）2, salicylaldehyde and tryptamine in hot ethanol solution and characterized by X-ray crystal structure analysis. The crystal belongs to monoclinic, space group P21/n with a = 15.014（2）, b = 10.857（1）, c = 17.489（1）A,β = 95.49（1）°, V = 2837.8（5） A^3, Z = 4, Dc = 1.386 g/cm^3, μ = 0.904 mm-1, F（000） = 1232, the final R = 0.0463 and wR = 0.0890 for 4990 independent reflections. In the complex, the Zn2＋ ion presents a distorted N2O2 tetrahedral coordination involving two H-1L ligands.

A Novel Copper(Ⅱ)Complex Based on 4-Amino-1,2,4-triazole Schiff-base:Synthesis,Crystal Structure,Spectral Characterization,and Hirshfeld Surface Analysis

A novel copper complex Cu2（L）4（1, HL = 2-ethoxy-6-（[1,2,4]triazol-4-yliminomethyl）-phenol） has been synthesized and characterized by IR, single-crystal X-ray diffraction, and elemental analysis（CHN）. The single crystal belongs to the triclinic system, space group P1 with a = 10.0991（10）, b = 10.5280（12）, c = 10.5777（11） A, α = 97.230（9）, β = 90.640（8）, γ = 92.412（9）°, Mr = 1052.05, V = 1114.6（2） A3, Z = 1, Dc = 1.567 g/cm3, F（000） = 542, μ = 1.029 mm–1, R = 0.0562 and w R = 0.1562. The fluorescence and electrochemiluminescence（ECL） of 1and HL ligand were studied. The luminescence properties of 1 can be attributed to the ligand-metal charge transfer.

Synthesis of Schiff Base Type Macrocycles Containing Naphthalene Ring

A series of new Schiff base type macrocyclic crown ethers containing naphthalene ring were synthesized from 2,2'-di(o-formylnaphthoxy) ethyl ether or 1,2-di(o-formylnaphthoxy) ethane and four appropriate diamines. The chemical structures of the new compounds were characterized by elemental analysis, infrared spectra, nuclear magnetic resonance spectra and mass spectrometry.

Synthesis of Novel C_2-Symmetric Chiral Polyamide Macrocycles Containing Pyridyl Side-arm

Three novel C2-symmetric macrocycles containing pyridyl units have been prepared by the cyclic condensation of chiral diamide intermediates with 2,6-pyridinedicarbonyl dichloride in highly diluted solution at room temperature.

Synthesis and Crystal Structure of a Novel 1D Mercury(II) Iodide Coordination Polymer Containing 40-Membered Macrocycle

A mercury coordination polymer [Hg3（TizT）216]n （Mr = 1921.72, TizT = 2,4,6- tri（imidazole- 1-yl）- 1,3,5-triazine） containing a 40-membered macrocycle which was constructed by four TizT ligands and four mercury（II） iodide molecules had been synthesized by the reaction of HgI2 with TizT. The complex was characterized by elemental analysis, FT-IR, ^1H NMR spectra and X-ray crystallography. The crystal of the complex belongs to the monoclinic system and C2/c space group with a = 35.840（5）, b = 8.169（5）, c = 14.980（5） A, β = 104.466（5）°, Z= 4, V= 4247（3） A^3, De = 3.006 g·cm^-3, μ= 15.223 mm^-1, F（000） = 3384, Rint = 0.0504, wR = 0.0833 and constructs a chair-like conformation of cyclohexane one by one, which forms a 1-D polymer through the fashion of fused ring aromatic hydrocarbon. The hydrogen bonds and π-π interactions shape the 2-D network structure. The two compounds excited weak fluorescence.

Synthesis and Crystal Structure of a Novel Bis(ethoxycarbonyl)glycoluril Macrocycle

A novel [2＋4＋2]-macrocyclic compound 3（C52H69N16O12, Mr = 1109.53） con- taining bis（ethoxycarbonyl）glycoluril groups was synthesized via the Mannich three-component reaction in one pot and its structure was characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 10.077（3）, b = 10.642（3）, c = 15.324（5） , α = 96.704（5）, β = 102.304（5）, γ = 104.546（5）°, Z = 2, V = 1528.7（8）3, Dc = 1.283 g/cm3, μ = 0.097 mm-1, F（000） = 628, R = 0.0818 and wR（I 〉 2σ（I）） = 0.2346 for 3034 observed reflections.

Synthesis and Electrical Conductivities of Fully Conjugated Schiff Base Macrocycles Containing 1,3,4-Oxadiazole

Conjugated Schiff base macrocycles containing 1,3,3-oxadiazole were prepared by [2 + 2] cyclic condensation of phenylenediamine with 2,5-bis(m-formyl-phenyl)-1,3,4-oxadiazole. These macrocycles with iodine or TCNQ produced stable charge-transfer complexes. The formation of complexes were identified by UV-Vis and FT-IR spectra.

Synthesis of phosphorus-containing polyoxamacrocycles with one to two reactive thiophosphoryl chloride groups

Novel phosphorus-containing polyoxamacrocycles with one to two reactive thiophosphoryl chloride groups 5, 6, 7, 8 were synthesized from bishydroxyl compounds 1, 2, 3, 4 and thiophosphoryl chloride respectively. Their structures were confirmed by ^ 1H NMR, ^13C NMR, ^31p NMR and elemental analysis.