Effect of fluoride ions on coordination structure of titanium in molten NaCl–KCl

The effects of fluoride ions(F^(-)) on the electrochemical behavior and coordination properties of titanium ions(Ti^(n+)) were studied in this work,by combining electrochemical and mathematical analysis as well as spectral techniques.The α was taken as a factor to indicate the molar concentration ratio of F^(-) and Ti^(n+).Cyclic voltammetry(CV),square wave voltammetry(SWV),and open circuit potential method(OCP)were used to study the electrochemical behavior of titanium ions under conditions of various α,and in-situ sampler was used to prepare molten salt samples when α equal to 0.0,1.0,2.0,3.0,4.0,5.0,6.0,and 8.0.And then,samples were analyzed by X-ray photoelectron spectroscopy(XPS) and Raman spectroscopy.The results showed that F^(-) in molten salt can reduce the reduction steps of titanium ions and greatly affects the proportion of valence titanium ions which making the high-valence titanium content increased and more stable.Ti^(2+) cannot be detected in the molten salt when α is higher than 3.0 and finally transferred to titanium ions with higher valence state.Investigation revealed that the mechanism behind those phenomenon is the coordination compounds(TiCl_(j) F_(i)^(m-)) forming.

CATHODIC REDUCTION OF METAL-CHLORIDE COORDINATION IONS

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Isomerism and coordination mode effects on two-photon absorption of tris(picolyl)amine-based fluorescent probes for zinc ions

One-photon absorption and two-photon absorption（TPA） properties of three tris（picolyl）amine-based zinc ion sensors are investigated by employing the density functional response theory in combination with the polarizable continuum model.The different isomer and coordination geometry of each probe are taken into account. Special emphasis is placed on the effects of isomerism and the coordination mode on the optical properties. The intra-molecular charge transfer（ICT）properties are specified by natural bond orbital charge analysis. It is shown that the isomerism has non-negligible effects on TPA properties of free ligands. It is found that both the TPA wavelength and the cross section are highly dependent on the coordination mode. When the zinc ion connects with the picolyl unit in the middle of a ligand, the zinc complex has a large TPA intensity in a long wavelength range due to the increased ICT mechanism.

COORDINATION CROSSLINKING OF NITRILE RUBBER FILLED WITH COPPER SULFATE PARTICLES

By incorporating copper sulfate （CuSO4） particles into acrylonitrile butadiene rubber （NBR） followed by heat pressing, a novel vulcanization method is developed in rubber through the formation of coordination crosslinking. This method totally differs from traditional covalent or non-covalent vulcanization approaches of rubber. No other vulcanizing agent or additional additive is involved in this process. By analyzing the results of DMA, XPS and FT-IR, it is found that the crosslinking of CuSO4 particles filled NBR was induced by in situ coordination between nitrogen atoms of nitrile groups （-CN） and copper ions （Cu^2＋） from CuSO4. SEM and EDX results revealed the generation of a core （CuSO4 solid particle）- shell （adherent NBR） structure, which leads to a result that the crosslinked rubber has excellent mechanical properties. Moreover, poly（vinyl chloride） （PVC） and liquid acrylonitrile-butadiene rubber （LNBR） were used as mobilizer to improve the coordination crosslinking of CuSO4/NBR. The addition of PVC or LNBR could lead to higher crosslink density and better mechanical properties of coordination vulcanization. In addition, crystal water in CuSO4 played a positive role to coordination crosslinking of rubber because it decreased the metal point of CuSO4 and promoted the metal ionization.

Sodium-Coordinated Polymeric Phthalocyanines as Stable High-Capacity Organic Anodes for Sodium-Ion Batteries

Sodium-ion batteries(SIBs)have attracted considerable interest as an alternative to lithium-ion batteries owing to their similar electrochemical performance and superior long-term cycle stability.Organic materials are regarded as promising anode materials for constructing SIBs with high capacity and good retention.However,utilization of organic materials is rather limited by their low energy density and poor stability at high current densities.To overcome these limitations,we utilized a novel polymeric disodium phthalocyanines(pNaPc)as SIB anodes to provide stable coordination sites for Na ions as well as to enhance the stability at high current density.By varying the linker type during a one-pot cyclization and polymerization process,two pNaPc anodes with O-(O-pNaPc)and S-linkers(S-pNaPc)were prepared,and their structural and electrochemical properties were investigated.The O-pNaPc binds Na ions with a lower binding energy compared with S-pNaPc,which leads to more facile Na-ion coordination/dissociation when engaged as SIB anode.The use of O-pNaPc significantly improves the redox kinetics and cycle stability and allows the fabrication of a full cell against Na_(3)V_(2)(PO_(4))_(2)F_(3)/C cathode,which demonstrates its practical application with high energy density(288 Wh kg^(-1))and high power density(149 W kg^(-1)).

Tuning the local coordination environment of silver(Ⅰ) coordination networks with counterions for enhanced electrocatalytic CO_(2) reduction

Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).

A 3-D Supramolecular Network with 1-D Cation Metal-organic Coordination Polymers and Diverse Motifs from Hydrogen-bonded [M(H_2O)_4]-Carboxylates

One-pot solvothermal reaction of Iransition metal Znn salt with 4,4-bipyddyl （bpy） and 1,4-benzenediacrylic add （H2L） in the presence of Et3N generates a three-dimensional （3-D） supramolecular network with 1-D cation metal-organic coordination polymer, [Zn（H20）a（bpy）]-L 1, and structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and photoluminescent property. The complex crystallizes in triclinic, space group P1 with a = 7.1291（2）, b = 7.3784（3）, c = 10.5042（3）A, α = 95.049（2）, β = 102.162（2）, 7 = 97.027（3）0, V= 532.38（3）A3, C22H24N2O8Zn, Mr = 509.82, De= 1.590 g/cm3, p（MoKa）= 1.207 ram-l, F（000） = 264, Z = 1,the finalR=O.0438and wR=O.lOll for 1589 observed reflections （I 〉 2σ（I））. In the crystal structure, the second building unit composed of [Zn（H2O）4].L constructs two distinct 2-D supramolecular sheets and a neutral 3-D architecture. The title compound 1 shows strong photoluminescence with emission maximum at 2 = 455 nm upon λex.max = 355 nm.

Structure and Coordination Investigation of Iron-ion Tinting Principle in Ferreous Glass

The tinting phenomena of iron oxide contained glasses were studied from aspects of the electronic configuration, the iron ions coordination fields and the ions structure in glass. Several iron ion tinting forms at different redox or COD (chemical oxygen demand) conditions and their influential factors were given necessary explanations. The results reveal that the Fe^(3+)-O-Fe^(2+) structure is the real tinting reason of iron involved glasses, whereas the Si^(4+)-O-Fe^(3+) and Si^(4+)-O-Fe^(2+) formulations modify the glass colours. Under oxidizing melting condition, the amount of 4/6-coordinated Fe^(3+) increases and makes the glass colour yellowish. Conversely, reducing melting condition makes the 6-coordinated Fe^(2+) increased and gives much blue tint to the glass. The conventional tank furnace melting the very strong reducing condition, which is of high COD glass batch, is not suitable. The high ratio of ferrous/ferric in glass can be obtained with a new refining technology which contains no or little amount of refining agent.

Responsive mechanism and coordination mode effect of a bipyridine-based two-photon fluorescent probe for zinc ion

The properties of one-photon absorption(OPA),emission and two-photon absorption(TPA)of a bipyridine-based zinc ion probe are investigated employing the density functional theory in combination with response functions.The responsive mechanism and coordination mode effect are explored.The structural fluctuation is illustrated by molecular dynamics simulation.The calculated OPA and emission wavelengths of the probe are consistent with the experimental data.It is found that the red-shift of OPA wavelength and the enhancement of TPA intensity are induced by the increased intra-molecular charge transfer mechanism upon metal binding.The structural fluctuation could result in the blue-shift of TPA wavelength and the decrease of the TPA cross section.The TPA properties are quite different among the zinc complexes with different coordination modes.The TPA wavelength of the complexes with two ligands is close to that of the probe,which is in agreement with the experimental observation.

Identification and Quantification of Intracoordination Water in Insoluble Pectinates Cu²⁺and Pb²⁺

By derivatography in insoluble pectins Cu2+ (РCu2+) and Pb2+ (РPb2+), the presence of “a high-temperature component” (150°C- 165°C) is established. During potentiometric alkalimetric titration of РCu2+ and РPb2+, endpoints are established at рН accordingly 4.87 and 4.95, proving acid properties of PM. Obtained data show the presence of water in the internal sphere of PM. Considering the loss of this water and the known ratio of metal cations and monomers of pectin (L-), the simplest formulas of pectins are established: [Cu(L-)2(H2O)2], [Pb(L-)2(H2O)4].

Quantum Chemical Calculations of the Structure,Property and Stability of Penta-coordinated Carbonium Ions Derived from Normal Butane

The structure and energy of the carbonium ions formed upon protonation of butane were studied by the DFT methods. Four stable structures are identified for the protonated form of n-butane,the energy increases in the following order:C2HC3<C1HC2<C2HH<C1HH,and the stability decreases in the following order C2HC3>C1HC2>C2HH>C1HH. The stability of the penta-coordinated carbonium ions may be explained by the electron distribution in the three-center-two-electron bonds. The delocalization of the penta-coordinated carbonium ion CHC with three-center-two-electron bonds on positive charges was stronger than that of the penta-coordinated carbonium ion CHH with three-center-two-electron bonds and its stability was higher than that of the penta-coordinated carbonium ion CHH with three-center-two-electron bonds.

Copper coordination-driven self-assembly and encapsulation of PCR reagents

Polymerase chain reactions(PCR)are a very important tool for use in cloning,nucleic acid sequencing and diagnostic testing.The storage conditions of PCR reagents are limited to freezing and a lot of mixing steps are needed.In this paper,we report using metal ions to form coordination nanomaterials with the intrinsic components of the PCR reagents including dNTP,DNA primers and DNA polymerase as an integrated PCR reaction system.To complete PCR reactions,users need only to dissolve the coordination nanomaterials with a buffer and add template DNA.A few transition metal ions were screened and Cu^(2+)was found to be the most effective metal ion for this purpose.Then the encapsulation efficiency of PCR reagents was measured,which can reach close to 100%for the primers and DNA polymerase,but only 10%for dNTP because dNTP was excess.Further study also exhibited this integrated PCR reaction system can be used for DNA detection with a similar detection limit to the normal PCR,and showed good stability of encapsulated PCR nanomaterial after storage for a week.

Layered coordination polymer with two-dimensional covalent bismuth-organic networks:Semiconductor and lithium ion storage

Single crystals of a bismuth-based coordination polymer(CP)with carboxyl-thiol ligands,[Bi(C_(8)H_(2)O_(4)S_(2))(C2H8N)]n(Bi-DSBDC-DMA,DMBDC=2,5-disulfur-1,4-dicarboxylate,DMA=dimethylamine),have been successfully synthesized.X-ray diffraction analysis reveals that Bi-DSBDC-DMA possesses a layered structure,with two-dimensional(2D)Bi-DSBDC networks alternating with layers composed of dimethylamine ions.This material demonstrates semiconducting properties,featuring an optical bandgap of 2.2 eV and an electrical conductivity of 2×10^(-8) S/cm.Furthermore,electrodes based on this material exhibit a capacity of 250 mAh/g after 200 cycles for lithium-ion storage.

Protein@PP-Zn nanocomplex assembled by coordination of zinc ions used for intracellular protein delivery

In recent years,intracellular delivery of protein drugs has attracted great attention,and polymer-based systems have been extensively exploited to develop efficient and safe carriers.However,efficient intracellular delivery of protein drugs remains a challenge because of the cell membrane barrier and endosome entrapment.Herein,we report a protein@PP-Zn nanocomplex,which consists of an imidazole-containing block polymer poly(ethylene glycol)-block-poly(β-amino ester)(PEG-b-PAE(Im),PP),zinc ions,and protein drugs,for efficient intracellular protein delivery.PEG-b-PAE(Im)could conjugate proteins via the bridging effect of zinc ions which simultaneously coordinate with imidazole groups on polymer and electron donor groups,such as imidazole and primary amine groups,on protein to improve the loading stability of proteins.Under a slightly acidic environment near cancer cells,the protonation of PAE(Im)backbone increases the positive charge density of the nanocomplex and promotes endocytosis.While under a more acidic environment in endosomes,further protonation of imidazole groups leads to the disintegration of the nanocomplex and the breakdown of endosomes because of the proton sponge effect.Finally,protein is released into the cytoplasm.With the assistance of the nanocomplex,proteins with different sizes and isoelectric points are effectively delivered into cells.This work provides a stable,efficient and universal strategy for intracellular protein delivery.

Characterization of Fluoride Phosphors for Diode Pumped Solid-State Lighting Applications

Phosphor coated diodes are critical to the lighting industry. Rare-earth doped fluoride phosphors are characterized in this work. Spectroscopy and lifetime measurements of CaF2: Dy3+, LaF3: Eu3+ and Tb3+-doped LaF3 and CaF2 crystals were performed by irradiating the samples with 405 and 375 nm diode lasers. Chromaticity diagrams are developed from spectral measurements. Dy3+-doped CaF2 revealed bright white light emission having peaks at 492, 570 and 654 nm. The measured color coordinates are x = 0.322 and y = 0.340 for Dy3+-doped CaF2 and these values are close to those of sunlight and the coordinated color temperature is 6147 K, under 405 m laser excitation. Eu3+-doped LaF3 revealed twenty emission peaks in the visible wavelength region. The color coordinates measured for LaF3: Eu3+ are x = 0.283 and y = 0.293 under 405 nm diode laser excitation and the color temperature is 9557 K. Eu3+-doped LaF3 provides cool white-light, under 405 nm diode laser excitation. Tb3+-doped fluoride crystals revealed bright white light under low power diode laser excitation. The measured color coordinates for Tb3+-doped CaF2 are x = 0.329 and y = 0.558 and the color temperature is 7713 K. The color coordinates for LaF3: Tb3+ are x = 0.342 and y = 0.365 and the coordinated color temperature is 5370 K. These values are close to those of sunlight.

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.

构建一维铜基配位聚合物作为锂离子电池正极材料

合成了一种新型的一维(1D)羰基配位聚合物[Cu(BGPD)(DMA)(H2O)]·DMA(记为Cu-BD,H2BGPD=N,N’-双(甘氨酰)均苯四甲酸二酰亚胺,DMA=二甲基乙酰胺),并考察了其用作锂离子电池正极材料的电化学性能。电化学测试结果表明,Cu-BD正极在50 mA·g^(-1)的电流密度下循环100圈后仍然保留50 mAh·g^(-1)的比容量,具有较好的循环稳定性。Cu-BD电极反应机理研究表明,BGPD2-配体和Cu(Ⅱ)离子在充放电过程中都可能参与了电子转移过程。

铜氨配离子结构与稳定性的理论研究

铜(Ⅱ)氨配离子是分析化学教学中配位平衡及配合物的分布特征部分较为经典的配离子之一。现行教材大多只给出了部分铜氨配离子的稳定常数,也并未解释铜氨配离子配位数与稳定性之间的关系。本文使用密度泛函理论,首先通过结构优化给出了铜氨配离子稳定性与配位数和结构的关系,而后进一步通过分析分子内部结构给出了一种回归结构本质的定性解释,既有助于改进教学效果,同时将理论计算应用于分析化学教学过程中,也可增加学生对理论计算的兴趣。

发光稀土-硫杂杯[4]芳烃配合物的研究进展

硫杂杯芳烃作为配体具有识别能力强、可“衍生化”、稳定性较好等优点。稀土离子与硫杂杯[4]芳烃配体易形成多功能金属簇配合物。稀土-硫杂杯[4]芳烃因具有独特的催化、磁学和光学等性质而受到越来越多的关注。硫杂杯[4]芳烃与稀土离子可通过酚羟基和桥连硫的配位发生有效的“天线效应”,使稀土离子敏化发光。综述了有关稀土-硫杂杯[4]芳烃配合物在光学性质方面的研究现状,论述了其结构、光学性质及应用。

基于羧酸基-酚羟基配体Pr配合物的结构、荧光性质以及辅助配体的影响

采用3,3′-偶氮双(6-羟基苯甲酸)二钠(Na_(2)H_(2)L)为配体,通过水热法与Pr^(3+)反应得到两个配合物[Pr(H_(2)L)0.5(L)0.5(H_(2)O)2]n(1)和Pr(H L)(phen)(H_(2)O)5·2H_(2)O(2)(phen=1,10-邻菲罗啉)。配合物1中,H_(2)L_(2)-阴离子作为四齿配体,2个羧酸基分别以μ2-η^(1)∶η^(1)的方式与Pr^(3+)配位,形成二维层状结构,并且L 4-阴离子作为桥连配体,利用羧酸基和酚羟基分别以μ2-η^(2)∶η^(1)和桥连模式将二维层中3个相邻的Pr^(3+)连接,将结构拓展成三维网络结构,其Schl fli符号为{4^(2)·8^(4)}{4^(6)·6^(6)·8^(3)}{4^(7)·6^(3)}2。引入phen分子,配合物2变为单核结构,phen与Pr^(3+)螯合配位,HL^(3-)作为单齿配体与Pr^(3+)配位。配合物1和2分别在6^(3)8和778 nm,652和781 nm处有Pr^(3+)的特征荧光发射峰,颜色落在色度图的橙色区域内,是^(1)S_(0)→^(1)I_(6)和^(1)D_(2)→3H 4能级跃迁所致。配合物2的荧光强度高于配合物1,且主峰红移14 nm,归因于phen的共轭体系以及与Pr^(3+)配位作用。