Lanthanum heterocyclic Schiff-base complex initiated ring-opening polymerization of ε-caprolactone

Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present.Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.

Synthesis and Crystal Structure of a Bimetallic Cyanide-bridged Complex Derived from Manganese(Ⅲ) Schiff-base Complex and Pentacyanidonitrosylferrate(Ⅱ) Building Blocks

A new cyanide-bridged bimetallic assembly [Mn（3-meosalpn）（H2O）]2[Fe（CN）5NO]（1） was obtained by the reaction of [Fe（CN）5NO]2-with [Mn（3-meosalpn）]＋,and characterized by elemental analysis,IR and single-crystal X-ray structure analysis.The complex crystallizes in the monoclinic system,space group P21/c with a = 12.992（5）,b = 13.274（6）,c = 14.644（6） ,β = 115.198（4）o,V = 2285.2（16）3,Z = 2,C43H44FeMn2N10O11,Mr = 1042.61,Dc = 1.515 g/cm3,F（000） = 1072,μ = 0.928 mm-1,S = 1.052,the final R = 0.0347 and wR = 0.0957 for 17377 observed reflections（Ⅰ 〉 2σ（Ⅰ））.X-ray single-crystal diffraction analysis reveals that 1 has a trinuclear molecular structure,in which the two [Mn（3-meosalpn）（H2O）]＋ cations are linked by the central [Fe（CN）5NO]2-anion via two trans CN-groups.Furthermore,the two [Mn（3-meo-salpn）（H2O）]＋ cations and [Fe（CN）5NO]2-anion are connected into a one-dimensional zigzag chain through hydrogen bonding interactions.

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.

Synthesis and Bioactivity of a Novel Bismuthoxide Schiff-base Complex Derived from Salen-like Ligand and Bismuth（III） Nitrate

In this paper, a novel bismuthoxide Schiff-base complex [Bi9O8（vanen）3（NO3）2（CH3OH）2（H2O）·3NO3· 5.5H2O]（abbreviated as Bivanen） was synthesized with Salen-like ligand Hzvanen[Hzvanen=N,N＇-ethylene bis（3-methoxysalicylideneimine）] and bismuth（III） nitrate. Its structure was characterized by IR spectra, NMR spectra and X-ray diffraction. In particular, the biology activities of the ligand and the complex against Schizosaecharomyees pombe（S, pombe） were studied using biological mierocalorimetry. The metabolic thermogenic curves of S. pombe were measured at 32.00 ℃. Then, some quantitative thermokinetic parameters of growth metabolism of S. pombe including the rate constant（k）, inhibition ratio（I） and half inhibition concentration（IC50） were calculated. Experimental results showed that the k values of S. pombe decreased while I values of S. pombe increased with the increase of concentrations of the ligand and the complex. The IC50 of the ligand and the complex were found to be 0.067 and 0.037 mmol/L, respectively.

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.

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 Novel Binuclear Cu(Ⅱ) Complex with Tetradentate Schiff-base Ligand

A novel binuclear complex （[Cu^2（μ2-shed）（hshed）].（CIO4）,H2O, h2shed = N-salicylidene-N＇-（2-hydroxyethyl）ethylenediamine） has been synthesized and structurally characterized by X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 12.511（10）, b = 15.750（12）, c = 14.281 （12） A, β = 100.564（14）°, C22H31CIN4O9Cu2, Mr = 658.04, V = 2766（4） A^3, Z = 4, Dc = 1.580 g/cm^3,μ（MoKα = 1.689 mm^-1, F（000） = 1352, the final R = 0.0528 and wR = 0.1433 for 4880 independent reflections with Rint = 0.0577. The complex is a binuclear copper compound, and two Cu（Ⅱ） ions in the binuclear cation are in different coordination environments. The Cu（1） ion adopts a distorted square pyramidal geometry （x = 0.22） with four donor atoms （N2O2） of the ligand in the basal plane, and one hydroxyl oxygen atom with protonated form occupying the apical position. The Cu（2） ion assumes the geometry of a distorted square plane with four donor atoms （N2O2） of the ligand. The Cu...Cu separation is 3.103 A,. In addition, N-H…O and C-H…O intermolecular hydrogen bonding interactions link these binuclear cations into a quasi one-dimensional chain along the a axis.

Crystal Structure of Binuclear Manganese(Ⅲ) Complex with Schiff-base Ligand,〔Mn_2(C_(22)H_(22)N_2O_2)_2(EtOH)_2 (bipy)〕(ClO_4)_2

The title complex, [Mn2L2(EtOH)2 (bipy )](ClO4)2 (L=N,N'-ethylenebis (1-phenyl-3-imino-1-butanonato), bipy = 4, 4'-bipyridine] crystallizes inmonoclinic system, space group P21/c with a= 12. 63O(5), b=13- 151 (2), c=18. 3773001 reflections The two [MnL(EtOH)]+ units are joined by one 4, 4'-bipyridine molecule to form a centrosymmetric binuclear complex cation [Mn2L2(EtOH)2 (bipy]2+. The coordination geometry around Mn atoms is a distorted octahe-dron with equatorial plane N2O2 from the Schiff base ligand L.

Heterogeneous degradation of toxic organic pollutants by hydrophobic copper Schiff-base complex under visible irradiation

A hydrophobic complex of Cu2＋[bis-salicylic aldehyde-o-phenylenediamine], Cu-SPA, was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation （λ≥420 nm） at neutral pH. The structure of complex was characterized by using nuclear magnetic resonance （NMR）, elemental analysis, IR and UV-vis spectrometries. Degradation of Rhodamine B （RhB）, Sulforhodamine B （SRB） and Benzoic acid （BA） in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA. The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution （the maximum adsorption amount： Qmax = 11.09 and 8.05 μmol/g, respectively）. Under visible irradiation, RhB and SRB were decolorized completely after 210 and 240 min, respectively, and BA was removed completely after 5 h. The efficiency of H202 was 〉 95%, in contrast to that of the reaction without catalyst or light （〈 20%）. In water soluble medium, the hydrophobic Cu-SPA can be used more than 6 cycles. ESR results and the behavior of cy- clic voltammetry showed that, in the reaction process, Cu2＋-SPA was reduced to intermediate state Cu＋-SPA firstly, which was extremely unstable and reacted rapidly with H2O2, leading to high reactive oxygen species （.OH radical ） to degrade the substrate.

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.

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 and Crystal Structure of a Cu(Ⅱ) Complex with Reduced Schiff-base N-(2-Hydroxybenzyl)-D,L-alanine and 4,4'-Bipyridine

A new complex [Cu2（sala）2（H20）2（4,4＇-bipy）]＇H20 （sala = N-（2-hydroxybenzyl）- D,L-alaninate, 4,4＇-bipy = 4,4＇-bipyridine） has been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. The complex crystallizes in monoclinic system, space group C2/c with a = 42.44（3）, b = 10.416（8）, c = 15.487（13） ./k, fl = 97.455（14）°, C30H36Cu2N4O9, Mr = 723.71, V = 6789（9） A3, Dc = 1.416 g/cm3, Z = 8, F（000） = 2992, μ（MoKa） = 1.308 mm-1, R = 0.0493 and wR = 0.1004 for 4878 observed reflections （I 〉 2σ（I））. Structural analysis shows that each copper（II） atom displays a distorted square-based pyramidal coordination geometry with two oxygen atoms and one nitrogen atom from one N-（2-hydroxybenzyl）-D,L-alaninate, one nitrogen atom from 4,4＇-bipyridine ligand and one water molecule. 4,4＇-Bipyridine ligand bridges two Cu（II） ions to form a dinuclear compound. The molecular structure is extended into a one-dimensional wavy chain through hydrogen bonds. These 1D chains are further expanded into 2D networks through hydrogen bonds.

Modeling time-dependent mechanical behavior of hard rock considering excavation-induced damage and complex 3D stress states

To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed.

Saturation Estimation with Complex Electrical Conductivity for Hydrate-Bearing Clayey Sediments:An Experimental Study

Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S_(h))models for reservoir evaluation and monitoring.The electrical properties of tetrahydrofuran-hydrate-bearing sediments with montmorillonite are characterized by complex conductivity at frequencies from 0.01 Hz to 1 kHz.The effects of clay and Sh on the complex conductivity were analyzed.A decrease and increase in electrical conductance result from the clay-swelling-induced blockage and ion migration in the electrical double layer(EDL),respectively.The quadrature conductivity increases with the clay content up to 10%because of the increased surface site density of counterions in EDL.Both the in-phase conductivity and quadrature conductivity decrease consistently with increasing Sh from 0.50 to 0.90.Three sets of models for Sh evaluation were developed.The model based on the Simandoux equation outperforms Archie’s formula,with a root-mean-square error(E_(RMS))of 1.8%and 3.9%,respectively,highlighting the clay effects on the in-phase conductivity.The fre-quency effect correlations based on in-phase and quadrature conductivities exhibit inferior performance(E_(RMS)=11.6%and 13.2%,re-spectively)due to the challenge of choosing an appropriate pair of frequencies and intrinsic uncertainties from two measurements.The second-order Cole-Cole formula can be used to fit the complex-conductivity spectra.One pair of inverted Cole-Cole parameters,i.e.,characteristic time and chargeability,is employed to predict S_(h) with an E_(RMS) of 5.05%and 9.05%,respectively.

Synthesis, structure, optoelectronic properties of novel zinc Schiff-base complexes

Two novel zinc Schiff-base complexes, bis-(N-(2-hydroxybenzidene)-p-aminodimethylaniline)zinc(II) (2) and bis-(N-(2-hydroxy-1-naphthidene)-p-aminodimethylaniline)zinc(II) (4) were designed and synthesized. Both the complexes exhibit good solubility in organic solvents and excellent thermal stabilities. A single crystal of 2 was grown and its crystalline structure was determined from X-ray diffraction data. Analysis of the electronic structures of both the zinc complexes calculated by density functional theory reveals a localization of orbital. The UV-Vis absorption and photoluminescence profiles of 4 in thin film are similar to those of 2, but the emission for 4 is red-shifted compared to 2. Three-layered devices with a configuration of ITO/NPB/2/Alq 3 /LiF/Al and ITO/NPB/4/Alq 3 /LiF/Al show a yellow and red emission, respectively.

Synthesis, Crystal Structure and Nonlinear Optical Properties of Nickel(Ⅱ) Complex with Schiff-base Ligand

The nickel(Ⅱ) complex with the new ligand of S-benzyl-b-N-[10-ethyl- phenothiazine-3-methylene]dithiocarbazate(HL) crystallizes in the triclinic system, space group P?with a = 7.516(1), b = 11.322(1), c = 13.366(1) , a = 84.818(1), b = 81.688(1), g = 76.037(1), V = 1090.26(3) 3, Z = 1, Dc = 1.413 g/cm3, F(000) = 482, m(MoKa) = 0.774 mm-1 (l = 0.7103 ?, R = 0.0573 and wR = 0.1375 for 3357 observed reflections with I ≥ 2s(I). The HL has lost a proton from its tautomeric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and b-nitrogen atoms. The geometry around Ni(Ⅱ) is almost square-planar with two equivalent NiN and NiS bonds. The nonlinear absorption of HL and NiL2 solutions (in DMF) was measured by open-aperture Z-scan technique at the wavelength of 532 nm.

DFT Studies on Second-order Nonlinear Optical Properties of a Series of Axially Substituted Bis（salicylaldiminato） Zinc（II） Schiff-base Complexes

Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical（NLO） re- sponse of a two-dimensional bis（salicylaldiminato） zinc（II） Schiff-base complex is an unprecedented model. The second-order NLO responses of a series of axially substituted bis（salicylaldiminato） zinc（II） Schiff-base complexes were explored according to the finite field（FF） method at CAM-B3LYP/6-31＋G（d） level（LANL2DZ basis set for metal atoms）. The results show that the second-order NLO properties can be effectively tuned by exchanging the do- nor and accepter of the axial ligand and extending the length of the conjugated bridge along the axial direction. A system involving the electron acceptor along the appropriate direction has a large three-dimensional second-order NLO response. Meanwhile, time dependent density functional theory（TD-DFT） method was employed to calculate the physical parameters of excited states. The results show that the Y- and Z-polarized transitions of the zinc（II） Schiff-base complex are the first and second excited states, respectively, and have a low-lying excited energy. Al- though the X-polarized transition has a high excited energy, the large oscillator strength indicates that it will signifi- cantly contribute to the second-order NLO response.

A novel complex-high-order graph convolutional network paradigm:ChyGCN

In recent years,there has been a growing interest in graph convolutional networks(GCN).However,existing GCN and variants are predominantly based on simple graph or hypergraph structures,which restricts their ability to handle complex data correlations in practical applications.These limitations stem from the difficulty in establishing multiple hierarchies and acquiring adaptive weights for each of them.To address this issue,this paper introduces the latest concept of complex hypergraphs and constructs a versatile high-order multi-level data correlation model.This model is realized by establishing a three-tier structure of complexes-hypergraphs-vertices.Specifically,we start by establishing hyperedge clusters on a foundational network,utilizing a second-order hypergraph structure to depict potential correlations.For this second-order structure,truncation methods are used to assess and generate a three-layer composite structure.During the construction of the composite structure,an adaptive learning strategy is implemented to merge correlations across different levels.We evaluate this model on several popular datasets and compare it with recent state-of-the-art methods.The comprehensive assessment results demonstrate that the proposed model surpasses the existing methods,particularly in modeling implicit data correlations(the classification accuracy of nodes on five public datasets Cora,Citeseer,Pubmed,Github Web ML,and Facebook are 86.1±0.33,79.2±0.35,83.1±0.46,83.8±0.23,and 80.1±0.37,respectively).This indicates that our approach possesses advantages in handling datasets with implicit multi-level structures.

Discovery of nano organo-clay complex pore-fractures in shale and its scientific significance:A case study of Cretaceous Qingshankou Formation shale,Songliao Basin,NE China

A new pore type,nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC,R_(o)values,X-ray diffraction etc.in the Cretaceous Qingshankou Formation shale in the Songliao Basin,NE China.Such pore characteristics and evolution study show that:(1)Organo-clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates.Different from circular or oval organic pores discovered in other shales,a single organo-clay complex pore is square,rectangular,rhombic or slaty,with the pore diameter generally less than 200 nm.(2)With thermal maturity increasing,the elements(C,Si,Al,O,Mg,Fe,etc.)in organo-clay complex change accordingly,showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fracture formation.(3)At high thermal maturity,the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70%of total pore space.The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores.It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil.The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significance for the study of shale oil formation and accumulation laws.