Copper-sulfide cluster assembled architecture via in situ reaction

A new copper-thiolate cluster assembled framework [Cu₂(μ₄-SCH₃)Cl]_n (1), has been solvothermally synthesized through in situ reaction viz., in situ ligand generation and metal reduction. Compound 1 represents the first 3D framework based on Atlas-sphere functionalized by single μ₂-Cl⁻ groups. DOS calculation reveals the interaction of electronic structures. It is found that the HOMO is mainly distributed on Cl, Cu and S bonding orbitals, while the LUMO is dominated by Cu-Cl antibonding orbitals.     

Voltammetric in situ measurements of trace metals in coastal waters

Developments in instrument miniaturisation and automation have resulted in the manufacture of portable electrochemical instrumentation for continuous trace-metal measurements from the banks of estuaries and on board ships. The most recent developments in flow cells with gel-coated iridium (Ir) micro-electrode arrays have resulted in submersible in situ voltammetric probes that allow long-term trace-metal monitoring at sub-nanomolar concentrations in coastal waters. This article overviews the design and the application of field-deployable voltammetric instrumentation for trace-metal monitoring.     

Biomimetic Preparation of Magnetite/Chitosan Nanocomposite via In Situ Composite Method ——Potential Use in Magnetic Tissue Repair Domain

IntroductionMagnetite (Fe3O4) is widespread in the environ-ment although it is thermodynamically unstable with re-spect to hematite(α-Fe2O3) in the presence of oxygen.It has been widely used for targeted delivery ofdrugs[1], in MRI reagents[2], hyperther…     

In situ Detection of Amide A Bands of Proteins in Water by Raman Ratio Spectrum

The amide A band of protein is sensitive to the hydrogen bands of amide groups of proteins. However, it is hard to distinguish the amide A band of aqueous protein in situ directly, since it overlaps with O-H stretching vibration of water. In this work, we presented a new analytical method of Raman ratio spectrum, which can extract the amide A band of proteins in water. To obtain the Raman ratio spectrum, the Raman spectrum of aqueous protein was divided by that of pure water. A mathematical simulation was employed to examine whether Raman ratio spectrum is effective. Two kinds of protein, lysozyme and α-chymotrypsin were employed. The amide A bands of them in water were extracted from Raman ratio spectra. Additionally, the process of thermal denaturation of lysozyme was detected from Raman ratio spectrum. These results demonstrated the Raman ratio spectra could be employed to study the amide A modes of proteins in water.     

Synthesis, in situ spectroelectrochemical, in situ electrocolorimetric and electrocatalytic investigation of brown-manganese phthalocyanines

α- and β-substituted tetrakis(6-hydroxyhexylthiol) phthalocyaninato manganese (III) chloride complexes have been prepared via cyclotetramerization. Both complexes have been characterized by elemental analysis, FTIR, MS and UV–Vis spectral data. The voltammetric and in situ spectroelectrochemical studies reveal that both complexes exhibit an oxidation and three reduction processes having reversible, one-electron, and diffusion controlled mass transfer characteristics, which are assigned to Mn^IIIPc²⁻/Mn^IVPc²⁻, Mn^IIIPc²⁻/Mn^IIPc²⁻, Mn^IIPc²⁻/Mn^IPc²⁻, and Mn^IPc²⁻/Mn^IPc³⁻ couples respectively. The existence of oxygen in solution significantly affects the in situ spectroelectrochemical behavior of the complexes due to the formation of μ-oxo MnPc species. An in situ electrocolorimetric method has been applied to investigate the colors of the electro-generated anionic and cationic forms of the complexes for the first time in this study. The complexes, coated on a glassy carbon electrode potentiostatically, show considerable high electrocatalytic activity to hydrogen evolution reactions in aqueous solution.     

In situ Fourier Transform Infrared Spectroscopy Diagnostic for Characterization and Performance Test of Catalysts

The present work establishes a systematic approach based on the application of in-situ Fourier transform infrared spectroscopy (FTIR) for the investigation of the crystal structure, thermal stability, redox behavior (temperature-programmed reduction/temperatureprogrammed re-oxidation) as well as the catalytic properties of Co₃O₄ thin films. The syntheses of Co₃O₄ were achieved by chemical vapor deposition in the temperature range of 400-500℃. The structure analysis of the as-prepared material revealed the presence of two prominent IR bands peaking at 544 cm^-1 (υ₁) and 650 cm^-1 (υ₂) respectively, which originate from the stretching vibrations of the Co-O bond, characteristic of the Co₃O₄ spinel. The lattice stability limit of Co₃O₄ was estimated to be above 650℃. The redox properties of the spinel structure were determined by integrating the area under the emission bands υ₁ and υ₂ as a function of the temperature. Moreover, Co₃O₄ has been successfully tested as a catalyst towards complete oxidation of dimethyl ether below 340 ℃. The exhaust gas analysis during the catalytic process by in situ absorption FTIR revealed that only CO₂ and H₂O were detected as the final products in the catalytic reaction. The redox behavior suggests that the oxidation of dimethyl ether over Co₃O₄ follows a Mars-van Krevelen type mechanism. The comprehensive application of in situ FTIR provides a novel diagnostic tool in characterization and performance test of catalysts.     

A novel synthetic route to metal–polymer nanocomposites by in situ suspension and bulk polymerizations

A novel strategy to synthesize hybrid metal–polymer nanocomposites has been achieved based on in situ free radical suspension and bulk polymerization techniques. An organometallic precursor complex is dissolved in a liquid monomer phase prior to polymerization, where upon the precursor molecules are immobilized inside the polymer matrix during its formation. In a separate step, metal nanoparticles are then formed by H₂-assisted reduction of the precursor in the polymer product in supercritical carbon dioxide (scCO₂). The synthesized nanocomposites were characterized by GPC, TGA, SEM and TEM. It is shown that the metal nanoparticles are uniformly distributed inside the polymer matrix and the inclusion of the metal precursor has no significant influence on the polymerization process. The current work represents a simple and universal way to prepare a variety of metal–polymer nanocomposite functional materials.     

Synthesis of Cu2O/Ag Composite with Visible Light Photocatalytic Degradation Activity for in situ SERS Analysis

A multifunctional Cu₂O/Ag micro-nanocomposite, which has the characteristics of high catalytic activities under the visible light and high surface-enhanced Raman scattering (SERS) activity, was fabricated via a facile method and employed for the in situ SERS monitoring of the photocatalytic degradation reaction of crystal violet. Through the variation of the AgNO₃ concentration, Ag content on the Cu₂O template can be controllably tuned, which has great influence on the SERS effect. The results indicate that Ag nanoparticles form on the Cu₂O nanoframes to obtain the Cu₂O/Ag nanocomposite, which can act as an excellent bifunctional platform for in situ monitoring of photocatalytic degradation of organic pollutions by SERS.     

原位XPS技术研究碳化铀的表面氧化

采用X射线光电子能谱(XPS)原位分析研究了298 K时烧结UC的清洁表面在O₂气氛中的初始氧化过程. UC试样清洁表面通过氩离子束长时间溅射获取. 初始反应各阶段U4f, O1s和C1s芯能级谱的变化显示样品表面的氧化产物为UO₂和自由碳. 当O₂饱和吸附后, UC表面氧化膜的增长呈抛物线型, 氧透过氧化膜的扩散为UC进一步氧化的速率控制步骤. 定量分析表明, 反应过程中U, C原子均未出现明显的表面偏析.     

Flame retardant polyamide 6 by in situ polymerization of ε-caprolactam in the presence of melamine derivatives

An improved method for preparing melamine cyanurate （MCA） based flame retardant polyamide 6 （FRPA6） materials has been proposed. This processing method, i.e., improved in situ polymerization, was used to synthesize flame retardant PA6. In situ formed MCA nanoparticles were supposed to be linked to PA6 chains in the ε-caprolactam hydrolytic polymerization system to obtain startype polymers for the first time. Through TEM photographs, it can be found that the in situ formed MCA nanoparticles with diametric size of less than 50 nm, are nanoscaled, highly uniformly dispersed in the PA6 matrix. Synthesized flame retardant PA6 have good fire performance which can achieve UL-94 V-0 rating at 1.6 mm thickness with the presence of 7.34 wt.% MCA in the matrix.     

Isothermal nucleation and growth kinetics of Pd/Ag alloy phase via in situ time-resolved high-temperature X-ray diffraction (HTXRD) analysis

Among several different approaches to form Pd/Ag alloys for hydrogen separation applications, ex situ studies carried out by conventional X-ray point scanning detectors might fail to reveal the key aspects of the phase transformation between Pd and Ag metals. In this respect, in situ time-resolved high-temperature X-ray diffraction (HTXRD) was employed to study the Pd/Ag alloy phase nucleation and growth kinetics. By the use of linear position sensitive detectors, advanced optics and profile fitting with the use of JADE-6.5 software, isothermal phase evolution of the Pd/Ag alloy at 500 °C, 550 °C and 600 °C under hydrogen atmosphere were quantified to elucidate the mechanistic details of the Pd/Ag alloy phase nucleation and growth pattern. Analysis of the HTXRD data by the Avrami model indicated that the nucleation of the Pd/Ag alloy phase was instantaneous where the growth mechanism was through diffusion-controlled one-dimensional thickening of the Pd/Ag alloy layer. The value of the Avrami exponent, n, was found to increase with temperature with the values of 0.34, 0.39 and 0.67 at 500 °C, 550 °C and 600 °C, respectively. In addition, parabolic rate law analysis suggested that the nucleation of the Pd/Ag alloy phase was through a heterogeneous nucleation mode, in which the nucleation sites were defined as the non-equilibrium defects. Indeed, the cross-sectional SEI micrographs indicated that the Pd/Ag alloy phase growth was strongly dependent upon the deposition morphology of the as-synthesized Pd and Ag layers formed by the electroless plating. Based on the Avrami model and the parabolic rate law, the estimated activation energies for the phase transformation were 236.5 kJ/mol and 185.6 kJ/mol and in excellent agreement with the literature values (183–239.5 kJ/mol). Finally, the in situ annealing of the 15.6 μm thick composite Pd/Ag/PSS membrane at 550 °C in hydrogen atmosphere indicated that the Pd/Ag alloy phase formation was not complete even after 500 h. According to the Avrami model, the increase in the hydrogen permeance from 7.1 m³/m² h atm^0.5 to 21.3 m³/m² h atm^0.5 at 550 °C over a period of 500 h corresponded to an 83% Pd/Ag alloy phase formation.     

N-甲基咪唑衍生物的原位紫外光谱电化学行为

用循环伏安法(CV)测定了寡聚酰胺单体N-甲基咪唑衍生物的电化学行为, 探讨用原位紫外光谱法对电化学反应过程进行检测, 观察到随极化电势的增加在紫外光谱中出现新的吸收峰, 分析了N-甲基咪唑衍生物的还原历程.     

In situ AFM study of electrochemical synthesis of polypyrrole/Au nanocomposite

In this work, in situ AFM measurements with simultaneously electrochemical characterization were developed to study the mechanisms of both polypyrrole (PPy) and PPy/Au composite deposition. The nanoscale information derived from the in situ AFM images associated with theoretical simulation from the measured current–time transient (i–t) reveals that Au nanoparticles with negatively charged carboxylic groups can be the nuclei by both adsorption on the electrode surface and doping on PPy for the polymerization, and thus has faster nucleation and growth rate than Py alone at the early polymerization stage. The PPy/Au deposition shows parallel nucleation processes of Au nanoparticle and Py, and an instantaneous 3D nucleation mode. The work not only provides fundamental insights for PPy/Au nanocomposite deposition process, but also optimization approaches to fabricate a superior PPy/Au film with favorable features for greater potential applications.     

Tandem reaction strategy of the Passerini/Wittig reaction based on the in situ capture of isocyanides: One-pot synthesis of heterocycles

This paper reports the tandem reaction strategy of the Passerini/Wittig reaction based on the in situ capture of isocyanides. According to this strategy, plenty of isocyanides have been synthesized, which is immediately used for the tandem reaction of Passerini/Wittig reaction in one pot. Compared to the previous work, this strategy avoids the separation, purification, and storage of isocyanides, which prominently solves the problems of isocyanide-based multicomponent reaction such as: (a) The environmentally unfriendly (strong foul odor), (a) the labile of Isocyanides, (c) high toxicity of isocyanides. In the meantime, in order to expand the application scope of our strategy, 1H-isochromenes and 3H-2-benzoxepin-1-ones have also been synthesized, which undergoes four-step transformations in one-pot. In addition, a relatively credible reaction mechanism has also been proposed, based on a series of control experiments. Furthermore, preliminary testing was performed on biological activity of some obtained compounds; These results showed that the synthesized compounds exhibited certain activity over P. digitatum and P. italicum. ^© 2019 Elsevier Science. All rights reserved.     

层层自组装原位聚合聚苯胺复合膜成膜机理研究

从苯胺单体出发, 通过原位聚合、现场掺杂以及基于静电力的层层自组装制备了聚苯胺复合膜. 通过苯胺活性溶液的温度及颜色变化跟踪聚合反应进程, 同时考察不同聚合反应阶段所得聚苯胺复合膜的紫外-可见吸收, 并进一步探讨聚苯胺复合膜的成膜机理. 研究表明, 成膜机制是由聚合反应初始阶段的苯胺阳离子或苯胺阳离子自由基通过静电作用快速吸附到负电性的基片表面, 形成均匀的聚合中心, 链增长生成聚苯胺; 该聚苯胺在酸性条件下经现场掺杂显电正性, 可吸附电负性的聚苯乙烯磺酸钠(PSS), 以此循环层层组装得到多层聚苯胺复合膜.     

In situ DRIFT study of nonoxidative methane reaction on Mo/SnO2 catalyst

A kinetic study of the homogeneous catalytic hydrogenation of avermectins is reported for a series of isosteric p-substituted arylphosphines as ligands. The activity of the rhodium complexes formed in situ from [RhCl(COD)]₂ increased with increasing the electron-donor capacity of the P(p-XC₆H₄)₃: P(p-ClC₆H₄)₃ < P(C₆H₅)₃ < P(p-CH₃C₆H₄)₃ < P(p-OCH₃C₆H₄)₃. As expected, this trend was also observed when using preformed complexes thereof. Linear correlations based on Hammett and Kabachnik treatments are provided as useful tools to guide the exploration work towards improved [RhCl(COD)]₂/P(p-XC₆H₄)₃ catalytic systems.     

Electrical field effects on dipole moment, structure and energetic of (H2O)n (2 n 15) cluster

The effect of an external electric field on water clusters of the (H₂O)_n type, with [1 n 15], in the ground state was analyzed at the B3LYP/cc-pVTZ level of theory. The calculations showed that an external electric field changes the number of hydrogen bonds, reduces the cluster sizes and increases the strength of the inter-cluster hydrogen bonds. The particular symmetry of the cluster and the null dipole moment in these specific configurations suggest that their stability can be associated with a perfect alignment of the water molecules, maximizing attractive electrostatic interactions caused by changes in the charge distribution of the clusters.     

In situ polymerization of methyl methacrylate/multi-walled carbon nanotube composites using cationic stearyl methacrylate copolymers as dispersants

Novel water-soluble amphiphilic copolymers (poly[(stearyl methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)]) for dispersing multi-walled carbon nanotubes (MWCNTs) were used to carry out in situ methyl methacrylate (MMA) polymerization. The morphology of the poly(methyl methacrylate)/MWCNT composites and the dispersion of the MWCNTs were analyzed by transmission electron microscopy. The dispersion of multi-walled carbon nanotubes in the composites was excellent for cationic SMA (stearyl methacrylate) copolymers, even at high MWCNT loading (6.0 wt.%). The mechanical properties and electrical and thermal conductivities of the composites were also analyzed. Mechanical properties were improved by MWCNTs; the strain at break values remained stable up to 6.0 wt.% MWCNT loading. Both electrical and thermal conductivities were improved by the addition of MWCNTs.     

New mixed-halide, boron-centered zirconium cluster phases with different cation distributions within a cluster framework: syntheses and structures of A[(Zr6B)ClxI14−x] (A=Na or Cs, 0x4)

Two new mixed-halide zirconium cluster phases have been synthesized by solid-state reactions in sealed tantalum containers from the Zr(IV) halides, elemental Zr and B, and NaI or CsCl, respectively. Single-crystal X-ray data were used to determine the crystal structures of Na[(Zr₆B)Cl_3.9I_10.1], and Cs[(Zr₆B)Cl_2.2I_11.8]. Both phases crystallize in a stuffed version of the [Nb₆Cl₁₄] structure type, orthorhombic, space group Cmca (Na[(Zr₆B)Cl_3.87(5)I_10.13]: a=15.787(2) Å, b=14.109(2) Å, c=12.505(2) Å, Z=4, R1(F)=0.0322 and wR2(F²)=0.0842; Cs[(Zr₆B)Cl_2.16(5)I_11.84]: a=15.696(4) Å, b=14.156(4) Å, c=12.811(4) Å, Z=4, R1(F)=0.0404 and wR2(F²)=0.1031). This structure type is constructed of clusters which contain centered (Zr₆Z) octahedra of the type [(Zr₆Z)X₁₂ⁱX₆^a] with Z=B and X=Cl and/or I. In both structures, chlorine and iodine atoms are randomly (to X-rays) distributed on the inner non-cluster-interconnecting ligand positions, whereas those sites which bridge metal octahedra are solely occupied by iodine. The phase widths for both phases have been found to cover 0x4 for A^I[(Zr₆B)Cl_xI_14−x]. Whereas the sodium cations in Na[(Zr₆B)Cl_xI_14−x] occupy 25% of a site which is octahedrally surrounded by halogen atoms, the larger cations in the cesium-containing phase occupy a 12-coordinate site within the cluster network.     

In situ X-ray powder diffraction, synthesis, and magnetic properties of InVO3

We report the first synthesis and high-temperature in situ X-ray diffraction study of InVO₃. Polycrystalline InVO₃ has been prepared via reduction of InVO₄ using a carbon monoxide/carbon dioxide buffer gas. InVO₃ crystallizes in the bixbyite structure in space group Ia−3 (206) with a=9.80636(31) Å with In³⁺/V³⁺ disorder on the (8b) and (24d) cation sites. In situ powder X-ray diffraction experiments and thermal gravimetric analysis in a CO/CO₂ buffer gas revealed the existence of the metastable phase InVO₃. Bulk samples with 98.5(2)% purity were prepared using low-temperature reduction methods. The preparative methods limited the crystallinity of this new phase to approximately 225(50) Å. Magnetic susceptibility and neutron diffraction experiments suggest a spin-glass ground state for InVO₃.