A Novel 3D Platinum–Thallium Coordination Polymer having Strong Metal–Metal Interactions

A new three-dimensional platinum(II)–thallium(I) coordination polymer [{Pt(pda)(NHCOtBu)₂}₄Tl₄][Pt(CN)₄]₂·2H ₂ O (pda = 1,2-propyldiamine) has been prepared from the direct reaction of [Tl₂Pt(CN)₄] and [Pt(pda)(NHCOtBu)₂] in water, and its structure was characterized by X-ray diffraction analysis. The compound crystallizes in monoclinic, space group Pn, a = 11.567(2) Å, b = 11.570(2) Å, c = 37.677(8)Å, β = 94.64(3)°, V = 5025.8(17) Å³, Z = 2, R1 = 0.0679 and wR2 = 0.1574 [I >  2σ (I)], Goodness-of-fit on F ² = 1.055. The compound exhibits a novel 3D network structure consisting of [Pt(CN)₄]^2? connected 1D infinite Pt–Tl–Pt–Tl chains via strong Pt–Tl bonds.     

Transformation of Structure and Properties of Vesicles Induced by Transition Metal Ions

This paper proved that octodecyl propylenediamine could form vesicles in pure water and aqueous solution of CuCl2 or Cu（NO3）2. The structure and morphology of vesicles were different when the copper （Ⅱ） salt was added to the solution. The results showed that both the counterions and the ligands had strong influence on the configuration of coordinated structures and packing model in bilayer membrane of vesicles.     

Unique Possibilities of Dynamic Metal–Polymer Interactions in Selective Hydrogenation

Rationally designed polymers can function as supports or promoters for metal catalysts, imparting distinct catalytic properties in selective hydrogenation. With strongly metal–ligating functional groups, mobile polymer chains can spontaneously decorate the metal catalyst surfaces under mild conditions, forming stable metal–polymer interfaces. We have termed this phenomenon ‘dynamic metal–polymer interaction (DMPI),’ which can be roughly considered as an organic version of the strong metal–support interaction (SMSI) concept. The polymer chains that dynamically interact with the metal surface can control the adsorption of reactants and products through competitive adsorption, significantly improving selectivity and catalyst stability. One of the remarkable advantages of using polymers as catalytic materials is that their molecular structures, such as molecular weight, crystallinity, and chemical functionality, can be tailored using rich organic chemistry. This, in turn, allows us to precisely tune the metal–polymer interactions and catalytic properties. In this Concept, we will discuss how metal–polymer interfaces can be designed and utilized for selective hydrogenation, with a particular emphasis on the industrially relevant acetylene partial hydrogenation reaction.     

Mixed-Isotope Labeling with LC-IMS-MS for Characterization of Protein–Protein Interactions by Chemical Cross-Linking

Chemical cross-linking of proteins followed by proteolysis and mass spectrometric analysis of the resulting cross-linked peptides provides powerful insight into the quaternary structure of protein complexes. Mixed-isotope cross-linking (a method for distinguishing intermolecular cross-links) was coupled with liquid chromatography, ion mobility spectrometry and mass spectrometry (LC-IMS-MS) to provide an additional separation dimension to the traditional cross-linking approach. This method produced multiplet m/z peaks that are aligned in the IMS drift time dimension and serve as signatures of intermolecular cross-linked peptides. We developed an informatics tool to use the amino acid sequence information inherent in the multiplet spacing for accurate identification of the cross-linked peptides. Because of the separation of cross-linked and non-cross-linked peptides in drift time, our LC-IMS-MS approach was able to confidently detect more intermolecular cross-linked peptides than LC-MS alone.      

Coordination Sorption of Urea by Novel Urea Sorbent——Polymer-bound Metal Complexes

Urea can be sorbed by coordination (or complexation)with transitional metalpolyacrylic acid complex and transitional metal-polyacrylamide containing polyethylenepolyamine ligand complexes. The experimental results indicate that the sorbents can sorb about 60mg urea per gram of sorbent at 37℃ and the concentration of urea was 1300.0rag/1 in NaH_2PO_4 and Na_2HPO_4 buffer solution (pH=7.0) and the urea sorption capacity was affected by many factors such as other competive ligands, sorption time, pH and the concentration of urea.     

Use of Metal Ions for the Estimation of the Efficiency of Antibody–Antigen Interactions

The applicability of Co(II), Ni(II), Fe(III), and Cr(III) ion labels to the immunochemical determination of ribonuclease, Candida albicans, Trichophyton rubrum, and Phoma betaeantigens was studied. The catalytic waves of hydrogen evolution, which occur in transition metal solutions in the presence of protein compounds, were used as analytical signals. The maximum catalytic effect depends on the pH, buffer capacity, and nature of buffer solution and on the nature of antigen to be determined. A new procedure was proposed for the immunochemical determination of the ribonuclease antigen using Co(II) ions as a label. The conditions of the formation and degradation of the antibody–antigen immune complex were found. The linear analytical range for the ribonuclease antigen was 0.005–1.0 mg/mL.     

Polymer–Metal Complexes Obtained by Radiation‐Induced Grafting Process onto Polyester Fabrics

Abstract

This paper reports the preparation of chelating copolymers via grafting of acrylic acid, and/or acrylamide onto polyester microfiber (PETMF) fabrics using a γ‐radiation technique. The effect of monomer concentration on the grafting process at irradiation dose 20?kGy was studied. The prepared graft chains (PETMF‐g‐AA), (PETMF‐g‐AAm), and (PETMF‐g‐PAAc/PAAm) acted as chelating sites for some selected transition metal ions. The effect of grafting on mechanical properties of PETMF and its copolymer–metal complexes was investigated. The prepared chelating copolymers and their metal complexes were characterized using x‐ray (energy dispersive x‐ray, EDX), differential scanning calorimeter (DSC), color parameters, and electrical conductivity measurements. The possibility of practical uses for such prepared graft copolymer–metal complexes was discussed and determined. The observed results showed that the electrical conductivity of the grafted copolymers and their metal complexes are thermally activated. Moreover, the degree of grafting enhanced the conductivity values of the grafted and non‐complexed copolymer up to three orders of magnitude, on the other hand, the conductivity of the copolymer–metal complexes slightly increased.     

Quantifying Protein–Protein Interactions by Molecular Counting with Mass Photometry

Interactions between biomolecules control the processes of life in health and their malfunction in disease, making their characterization and quantification essential. Immobilization- and label-free analytical techniques are desirable because of their simplicity and minimal invasiveness, but they struggle with quantifying tight interactions. Here, we show that mass photometry can accurately count, distinguish by molecular mass, and thereby reveal the relative abundances of different unlabelled biomolecules and their complexes in mixtures at the single-molecule level. These measurements determine binding affinities over four orders of magnitude at equilibrium for both simple and complex stoichiometries within minutes, as well as the associated kinetics. These results introduce mass photometry as a rapid, simple and label-free method for studying sub-micromolar binding affinities, with potential for extension towards a universal approach for characterizing complex biomolecular interactions.     

Interactions of Nabumetone with γ-Cyclodextrin Studied by Fluorescence Measurements

The inclusion of the anti-inflammatory drug, Nabumetone (NAB), in γ-cyclodextrin (γ-CD) was studied by fluorescence measurements. The emission fluorescence spectrum, of NAB reveals a maximum whose intensity increases with the different γ-CD’s growing concentrations. The stoichiometery (1:1) and binding constants of the complexes at 15, 25, 35, and 45 °C were extracted from the analysis of the emission spectra of NAB. The thermodynamic parameters ΔH ° and ΔS ° for the formation of the complex were calculated from the temperature dependence of the binding constants and compared with previous results for similar complexes of NAB with α- and β-CDs. The location of NAB in the complex was determined using the fluorescence quenching method. Our results indicate that NAB is completely penetrated into the cavity of γ-CD.This revised version was published online in July 2005 with a corrected issue number.     

Synthesis and Structural Characterization of Three Novel Macrocyclic Coordination Complexes Formed by Self-assembly of Bridged Bi-or Tetrapyridine with Transition Metal Salts

Serf-assembly of a ferrocenyl-bridged bipyridine ligand bpef [bpef=1, 1＇-bis（trans-2-pyrid-4＇-ylethenyl）ferrocene] with silver triflate in CH2Cl2/MeOH or mercuric diiodide in MeCN/CH2Cl2 gave the corresponding macrocyclic coordination complexes [bpef]2[AgSO3CF3]2 （1） and [bpef]2[Hg3I6] （2） in 93% and 89% yields, respectively, whereas the pentaerythritolyl-bridged tetrapyridine ligand ptpc [ptpc=pentaerythritol tetrakis-（4-pyridinecarboxylate）] reacted with cobalt thiocyanate via self-assembly to afford the macrocyclic coordination polymer [Co（NCS）2（ptpc）], （3） in 90% yield. The X-ray diffraction analyses for 1-3 confirmed their novel macrocyclic structures and revealed that （i） the two silver atoms in complex 1 have an essentially linear geometry with N-Ag-N bond angle of 175.7° and 172.9°, （ii） the geometry of the middle mercury atom in complex 2 is square-planar, while the other two mercury atoms in the other two complexes are tetrahedral, and （iii） all the cobalt atoms in complex 3 adopt an octahedral geometry. In addition, the synthetic procedure for the known tetrapyridine ligand ptpc has been improved.     

Sorption of Molecular Oxygen by Metal–Ion Exchanger Nanocomposites

Kinetic features are studied of the chemisorption and reduction of molecular oxygen from water by metal–ion exchanger nanocomposites that differ in the nature of the dispersed metal and state of oxidation. In the Pd < Ag < Cu series, the increasing chemical activity of metal nanoparticles raises the degree of oxygen sorption due to its chemisorption and subsequent reduction, while the role of the molecular chemisorption stage increases in the Cu < Ag < Pd series. Metal particles or their oxides are shown to act as adsorption sites on the surface and in the pores of the ion-exchanger matrix; the equilibrium sorption coefficient for oxygen dissolved in water ranges from 20 to 50, depending on the nature and oxidation state of the metal component.

     

Highly sensitive determination of 1,1-dimethylhydrazine by high-performance liquid chromatography–tandem mass spectrometry with precolumn derivatization by phenylglyoxal

A new highly sensitive and rapid approach to the determination of 1,1-dimethylhydrazine in natural water is developed (determination range is 0.03–1 μg/L). It is based on the use of high-performance liquid chromatography–tandem mass spectrometry with precolumn derivatization by phenylglyoxal and does not require any preconcentration. Derivatization, chromatographic separation conditions, and tandem mass spectrometry detection parameters are chosen. Intra-day precision of the results of measurements of 1,1- dimethylhydrazine in natural water is 12–16%, and inter-day precision is 16–22%. The lowest limit of detection and the lowest limit of quantification are 0.010 μg/L and 0.030 μg/L, respectively.     

Efficient Trapping of Trace Acetylene from Ethylene in an Ultramicroporous Metal–Organic Framework: Synergistic Effect of High-Density Open Metal and Electronegative Sites

Acetylene (C₂H₂) removal from ethylene (C₂H₄) is a crucial step in the production of polymer-grade C₂H₄ but remains a daunting challenge because of the similar physicochemical properties of C₂H₂ and C₂H₄. Currently energy-intensive cryogenic distillation processes are used to separate the two gases industrially. A robust ultramicroporous metal–organic framework (MOF), Ni₃(pzdc)₂(7 Hade)₂, is reported for efficient C₂H₂/C₂H₄ separation. The MOF comprises hydrogen-bonded linked one-dimensional (1D) chains, and features high-density open metal sites (2.7 nm⁻³) and electronegative oxygen and nitrogen sites arranged on the pore surface as cooperative binding sites. Theoretical calculations, in situ powder X-ray diffraction and Fourier-transform infrared spectroscopy revealed a synergistic adsorption mechanism. The MOF possesses S-shaped 1D pore channels that efficiently trap trace C₂H₂ at 0.01 bar with a high C₂H₂ uptake of 60.6 cm³ cm⁻³ and C₂H₂/C₂H₄ selectivity.     

Electrochemical Detection of Host–Guest Interactions of Dicarboximide Pesticides with Cyclodextrins

Electrochemical methods sensitively detect the formation of host–guest complexes of cyclodextrins and three redox-active pesticides: vinclozoline (3-(3,5-dichlorophenyl)-5-methyl-5-vinyl-1,3-oxazolidine-2,4-dione), iprodione (3-(3,5-dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide), and procymidone (3-(3,5-dichloro-phenyl)-1,5-dimethyl-3-azabicyclo[3.1.0]hexane-2,4-dione). The protecting environment of the CD cavity allows a four-electron heterogeneous reaction leading to a preferential cleavage of the C–Cl bonds and conservation of the heterocycle structure for a further second electron transfer step. This interpretation is supported by numerical simulation of the voltammetric curves and by quantum-chemical calculations of the LUMO changes of vinclozoline. Electrochemical detection of these host–guest interactions is far superior to the spectral methods.     

Engineering Heterogeneous Catalysis with Strong Metal–Support Interactions: Characterization,Theory and Manipulation

Strong metal–support interactions (SMSI) represent a classic yet fast-growing area in catalysis research. The SMSI phenomenon results in the encapsulation and stabilization of metal nanoparticles (NPs) with the support material that significantly impacts the catalytic performance through regulation of the interfacial interactions. Engineering SMSI provides a promising approach to steer catalytic performance in various chemical processes, which serves as an effective tool to tackle energy and environmental challenges. Our Minireview covers characterization, theory, catalytic activity, dependence on the catalytic structure and inducing environment of SMSI phenomena. By providing an overview and outlook on the cutting-edge techniques in this multidisciplinary research field, we not only want to provide insights into the further exploitation of SMSI in catalysis, but we also hope to inspire rational designs and characterization in the broad field of material science and physical chemistry.     

Amorphization of Metal–Organic Framework MOF-5 by Electrical Discharge

Amorphization of various solid materials has attracted increasing attentions. We report here an amorphization of metal–organic framework-5 (MOF-5) of composition Zn₄O(BDC)₃ (BDC = 1,4-benzenedicarboxylate) using dielectric-barrier discharge (DBD) treatment at ambient pressure and low gas temperature (around 120°C). The irreversible amorphization was confirmed by x-ray diffraction (XRD) characterization. The result of N₂ adsorption–desorption measurements revealed a collapse of pores, which further supported the XRD results. The destroying of part of carboxylate groups might be the main reason resulting in the amorphization of MOF-5.     

Intense Red-Blue Luminescence Based on Superfine Control of Metal–Metal Interactions for Self-Assembled Platinum(II) Complexes

A series of assembled Pt^II complexes comprising N-heterocyclic carbene and cyanide ligands was constructed using different substituent groups, [Pt(CN)₂(R-impy)] (R-impyH⁺=1-alkyl-3-(2-pyridyl)-1H-imidazolium, R=Me ( Pt-Me ), Et ( Pt-Et ), ⁱPr ( Pt- ⁱ Pr ), and ^tBu ( Pt- ^t Bu )). All the complexes exhibited highly efficient photoluminescence with an emission quantum yield of 0.51–0.81 in the solid state at room temperature, originating from the triplet metal-metal-to-ligand charge transfer (³MMLCT) state. Their emission colors cover the entire visible region from red for Pt-Me to blue for Pt- ^t Bu . Importantly, Pt- ^t Bu is the first example that exhibits blue ³MMLCT emission. The ³MMLCT emission was proved and characterized based on the temperature dependences of the crystal structures and emission properties. The wide-range color tuning of luminescence using the ³MMLCT emission presents a new strategy of superfine control of the emission color.     

Copolymerization of Styrene with N—phenylmaleimide by Rare Earth Coordination Catalysts

Copolymerization of styrene (St) with N-phenylmaleimide(NPMI) was studied with rare earth coordination catalyst Nd(naph)3-AlEts in toluene. Characterization of the copolymers showed that the copolymers possess an alternating structure.     

A Proximity-Induced Fluorogenic Reaction Triggered by Antibody–Antigen Interactions with Adjacent Epitopes

Proximity-induced chemical reactions are site-specific and rapid by taking advantage of their high affinity and highly selective interactions with the template. However, reactions induced solely by antibody–antigen interactions have not been developed. Herein, we propose a biepitopic antigen-templated chemical reaction (BATER) as a novel template reaction. In BATER, reactive functional groups are conjugated to two antibodies that interact with two epitopes of the same antigen to accelerate the reaction. We developed a method for visualizing the progress of BATER using fluorogenic click chemistry for optimal antibody selection and linker design. The reaction is accelerated in the presence of a specific antigen in a linker length-dependent manner. The choice of the antibody epitope is important for a rapid reaction. This design will lead to various applications of BATER in living systems.     

A Quartz Crystal Microbalance Characterization of Metal‐Oil Interfaces and Interactions with Wax Molecules

The solid‐liquid interface between stainless steel and model petroleum fluids is investigated at isothermal conditions using a quartz crystal microbalance. AISI 316 (Fe/Cr18/Ni10/Mo3) stainless steel is chosen to represent the metal surface. Paraffin components dissolved in dodecane constitute the petroleum fluid phase. Commercial macro‐crystalline and micro‐crystalline waxes provide primarily linear and branched paraffin components, respectively. Paraffin solubility conditions are established through a van't Hoff relationship. Model fluids prepared with the single‐component alkanes n‐C₃₆ or n‐C₃₀ paraffin provide well‐defined solubility conditions. Monitored changes in resonance frequency and energy dissipation of the quartz crystal resonator immersed in the model fluids confirm that no continual deposition of paraffin components occurs at isothermal conditions. Solid paraffin crystals dispersed in solution show no adherence to the stainless steel surface. The absence of attractive interactions between the stainless steel surface and the dispersed paraffin crystals suggests that a surface adsorption and/or surface nucleation mechanism is responsible for the formation of incipient paraffin wax deposits under nonquiescent conditions.