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.

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)).

CATHODIC REDUCTION OF METAL-CHLORIDE COORDINATION IONS

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Synthesis of lithium difluoro(oxalate)borate(LiODFB), phase diagram and ions coordination of LiODFB in dimethyl carbonate

A new two-step synthetic method was successfully developed to simplify the recrystallization process of lithium difluoro(oxalate)borate(LiODFB).Meanwhile,the purity of LiODFB as-prepared was determined by NMR,ICP-AES and Karl Fisher measurements,respectively.The as-prepared LiODFB presents a high purity up to 99.95%.Its metal ions and water contents are under good control as well.Besides,its structure information and thermal properties were confirmed by FTIR,Raman and DSC-TGA analyses,respectively.LiODFB exerts fine thermostability and hypo-water-sensitivity and its structure information agrees well with previous literature.Furthermore,a combination of phase diagram and Raman spectroscopy were utilized to study the thermal phase behavior and ions coordination of LiODFB-DMC binary system to optimize the synthesis and recrystallization process.Although there are three types of molecular interaction forms(CIPs,AGG-IIa,AGG-IIIb)in LiODFB-DMC binary system,LiODFB can only be isolated as large single crystal solvate as LiODFB·(DMC)3/2 by slowly cooling subjected to the nucleation kinetics.Therefore,the fundamental information of our work is helpful in accelerating the application of LiODFB in Li-ion secondary batteries.

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.

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.

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].

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.

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).

Effects of synthesis conditions on layered Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 positive-electrode via hydroxide co-precipitation method for lithium-ion batteries

Layered Li[Ni1/3Co1/3Mn1/3]O2 was synthesized with complex metal hydroxide precursors that were prepared by a co-precipitation method.The influence of coordination between ammonia and transition-metal cations on the structural and electrochemical properties of the Li[Ni1/3Co1/3Mn1/3]O2 materials was studied.It is found that when the molar ratio of ammonia to total transition-metal cations is 2.7：1,uniform particle size distribution of the complex metal hydroxide is observed via scanning electron microscopy.The average particle size of Li[Ni1/3Co1/3Mn1/3]O2 materials was measured to be about 500 nm,and the tap-density was measured to be approximately 2.37 g/cm3,which is comparable with that of commercialized LiCoO2.XRD analysis indicates that the presently synthesized Li[Ni1/3Co1/3Mn1/3]O2 has a hexagonal layered-structure.The initial discharge capacity of the Li[Ni1/3Co1/3Mn1/3]O2 positive-electrode material is determined to be 181.5 mA·h/g using a Li/Li[Ni1/3Co1/3Mn1/3]O2 cell operated at 0.1C in the voltage range of 2.8-4.5 V.The discharge capacity at the 50th cycle at 0.5C is 170.6 mA·h/g.

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。

黄绿色葡萄石的谱学特征及颜色成因

颜色是宝石重要的光学性质之一,也是影响宝石品质及价格的重要参数。黄绿色葡萄石作为一种常见的玉石品种,其结构、致色离子的种类、价态及配位的复杂性,导致前人关于其致色成因存在较大的争议。采用傅里叶红外吸收光谱(FTIR)、紫外-可见光分光光谱(UV-Vis)、激光剥蚀-等离子体质谱(LA-ICPMS)及穆斯堡尔谱(Mössbauer)等现代分析测试手段,对2个典型的黄绿色葡萄石样品(浅黄绿色样品LYG和深黄绿色样品DYG)的主要致色离子种类、价态及配位状态进行了深入研究,为黄绿色葡萄石的致色成因提供科学的解释。UV-Vis分析结果表明,样品LYG和样品DYG均出现明显的~425和~585nm处的吸收带,分别与Fe^(3+)oct的电子跃迁和Fe^(2+)ch-Fe^(3+)oct的电荷转移有关。Mössbauer超精细参数分析结果显示,样品LYG和样品DYG中Fe^(3+)的IS均为0.34mm·s^(-1),QS值分别为0.22和0.35mm·s^(-1),均符合葡萄石八面体配位中Fe^(3+)的特征。样品LYG(IS=1.08mm·s^(-1))和样品DYG(IS=1.07mm·s^(-1))的Fe^(2+)具有相近的IS值,均符合八面体配位中Fe^(2+)的特征。然而,样品DYG中Fe^(2+)的QS值(QS=2.78mm·s^(-1))明显高于样品LYG(QS=1.12mm·s^(-1)),说明前者结构中Fe^(2+)处于畸变的八面体中。样品DYG结构中Fe的含量和Fe^(2+)的比例(4.02wt%;11.88%)均高于样品LYG(3.55wt%;5.27%),表明黄绿色葡萄石的颜色可能与Fe的含量和Fe^(2+)的比例有关。样品LYG和样品DYG中V的含量分别为633和1810μg·g^(-1),指示V可能对黄绿色葡萄石的颜色有贡献,但含量明显低于Fe,所以V对颜色的贡献远低于Fe^(3+)和Fe^(2+)。该研究不仅查明了黄绿色葡萄石的主要致色离子种类(Fe),而且确定了致色离子的价态(Fe^(3+)和Fe^(2+))和配位状态(八面体配位),为黄绿色葡萄石颜色的定量研究提供了有益的基础素材。

基于弱配位环境的晶态锌离子固态电解质

二次锌电池是一类低成本、环保和高安全的规模储能技术,但是一直以来锌金属负极与传统水系电解液兼容性不足以及严重的枝晶生长问题限制了电池能量密度和寿命。发展固态二次锌电池是根本解决上述瓶颈问题的有效路线之一,但是,二价锌离子电荷密度高,其在无机陶瓷电解质和聚合物电解质中的室温固相传导极为困难。本工作以具有层状晶体结构的三氟甲基磺酸锌[Zn(TFO)_(2)]作为离子盐主体骨架,通过引入“软碱”的双齿弱配位配体——丁二腈(SN)重塑锌离子的固相配位环境,发展了一类晶态配位化合物的锌离子固态电解质[Zn(TFO)_(2)(SN)_(n)]。得益于氰基官能团(—CN)与三氟甲基磺酸阴离子(TFO^(-))的共配位结构,阴离子骨架对锌离子的静电束缚得到了显著降低,锌离子室温固态离子电导率实现了3个数量级的提升[由Zn(TFO)_(2)的1.1×10^(-9)S/cm提升至1.8×10^(-6)S/cm]。基于该类固态电解质,Zn||Zn对称电池可实现低极化电压(0.08 V,0.05 mA/cm^(2))的长周期锌沉积/溶解循环,并且实现了全固态锌空气电池在室温下的可逆充放电。

含四烯基吡啶配体的Zn(Ⅱ)配位聚合物的合成、结构及其荧光性质

在3,5-二硝基苯甲酸(3,5-HDNBA)、4-吡唑羧酸(4-H_(2)PyC)或对乙基苯甲酸(4-HEBA)存在下,Zn(NO_(3))_(2)·6H_(2)O与1,2,4,5-四(4-乙烯基吡啶基)苯(tkpvb)发生溶剂热反应,制备了[Zn(tkpvb)(3,5-DNBA)_(2)]n(CP1)、{[Zn(tkpvb)(4-PyC)·2H_(2)O]}n(CP2)和{[Zn(tkpvb)0.5(4-EBA)_(2)]·H_(2)O}n(CP3)三种Zn(Ⅱ)基配位聚合物(CPs)。通过红外光谱、元素分析、粉末X射线衍射和单晶X射线衍射对它们进行了结构表征。CP1具有一维“之”字形链状结构,CP2和CP3则分别呈现六连接和四连接的三维拓扑结构。CP1~CP3均表现出光致发光现象,对无机金属离子有一定的响应性能。其中,Fe_(3)+离子对CP1的荧光强度影响最大,检测限达到0.020µmol·L^(-1)。这可能是Fe_(3)+与CP1中不配位的吡啶基之间的相互作用引起的。

近岸海域溶解有机质与金属离子的配位机制及溶解氧的影响特性

溶解有机质(DOM)能与金属离子配位,从而影响金属离子的毒性、迁移转化以及生物可利用性,对近岸养殖区的生态环境产生深远的影响。本文利用三维荧光光谱结合平行因子法研究了舟山近岸海域DOM的组成,采用荧光猝灭滴定并运用修正Stern-Volmer模型系统研究了DOM各荧光组分与典型的过渡金属离子Cu^(2+)、Fe^(3+)和Pb^(2+)的配位机制,并进一步研究了海水溶解氧对DOM与Cu^(2+)、Fe^(3+)和Pb^(2+)配位作用的影响。结果表明:舟山近岸海域DOM的4种荧光组分,两种类腐殖质组分(C1、C2)明显比2种类蛋白质组分(C3、C4)更易与金属离子配位;DOM与金属离子配位化合物稳定性大小依次是:Cu-DOM>Fe-DOM>Pb-DOM;此外,缺氧环境明显抑制了溶解有机质与Fe^(3+)的配位能力,但Cu^(2+)、Pb^(2+)的配位能力则几乎不受溶解氧浓度的影响。这些结果将为海水养殖水体的调控、恢复提供科学依据。

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。