Li~+,Na~+,K~+,Mg~(2+)/Cl~-,SO_4~(2-)-H_2O体系Pitzer热力学模型

介绍了描述25℃Li+,Na+,K+,Mg2+/Cl-,SO42--H2O体系的热力学Pitzer模型.给出了为获得Pitzer混合参数而测定的Li+/Cl-,SO42--H2O,Li+,K+/Cl--H2O,Li+,Na+/Cl--H2O等三元体系和Li+,Mg2+/Cl-,SO42--H2O四离子体系溶液的渗透系数.详细叙述如何利用热力学数据和溶解度数据,获得Li+,Mg2+/Cl-,SO42--H2O,Li+,K+/Cl-,SO42--H2O,Li+,Na+/Cl-,SO42--H2O体系全部混合参数及7种锂盐Gibbs标准生成自由能.进而通过数据对比,介绍了本模型在含Li+多组分溶液25℃热力学性质计算、含Li+多组分体系25℃溶解相平衡预测等方面的应用.     

金属离子与腺嘌呤异构体复合物的稳定性

在B3LYP/6-311++G**//6-31+G*基组水平上结合PCM模型系统的优化了气相和液相环境中14种腺嘌呤异构体与四种金属离子(Na+,K+,Mg2+,Ca2+)形成的132个稳定复合物。通过能量对比,得到了所有复合物异构体在气液两相中的稳定性顺序及不同金属离子与同一异构体形成的复合物的能量排序,首次给出了液相中这些不同金属离子复合物的最稳定结构。结果发现溶剂效应导致了液相中的复合物稳定性顺序与气相中的相比发生了很大变化;同一异构体与不同金属离子形成的复合物其稳定性在排序中也变化很大。对于这些变化,本文分别从金属离子与腺嘌呤的复合物在气相中的结合能(EBE)及在液相中的溶质溶剂相互作用能(Epol)能等方面进行了系统的阐述     

K~+、Na~+、Ca~(2+)、Mg~(2+)对胜利褐煤平衡复吸水的影响

以胜利褐煤为研究对象,利用FT-IR等手段,用灰分、不同湿度下的平衡复吸水含量等,系统研究了不同相对湿度下K+、Na+、Ca2+、Mg2+的水合作用对胜利褐煤平衡复吸水含量的影响。结果表明,相同浓度不同类型的金属离子与煤样的交换能力的趋势为Ca2+Na+K+Mg2+。金属离子对胜利褐煤平衡复吸水含量影响力的顺序为Mg2+Ca2+Na+≈K+。相对湿度高时,平衡复吸水含量的主要控制因素为游离水分子之间的分子作用力;相对湿度中等时,平衡复吸水含量的主要控制因素为金属水簇与毛细管之间的毛细管作用力;相对湿度低时,平衡复吸水含量的主要控制因素为金属离子的水合作用。     

Ni2+和Cd2+跨人红细胞膜的比较研究

以往对金属离子跨红细胞膜转运多集中在体内的宏量金属离子, 如Na+, K+, Ca2+, Mg2+及某些必需的重金属元素Fe2+, Cu2+, Zn2+等[1～3], 对其它重金属离子的跨膜转运研究较少. 我们曾研究了具有不同电荷的Co(Ⅲ)配合物的红细胞摄入动力学及机理[4]. 在此基础上进一步选择离子电荷数相同, 但电子组态不同的两个金属离子Ni2+和Cd2+为研究对象. Ni2+为d8组态, 动力学上是惰性的, 为体内必需的微量元素; 而Cd2+为d10组态, 动力学上是活性的, 却为有毒重金属, 本研究比较了它们跨人红细胞膜传递的动力学以及其与人红细胞作用的差异性.     

溶液中Zn2+与腺嘌呤异构体间相互作用的理论研究

用B3LYP/6-311++G**方法和PCM及Onsager模型研究了Zn2+与腺嘌呤异构体在溶液中的11种较为稳定配合物. 结果显示, 这些配合物在溶液中的稳定性顺序与气相中明显不同, 其结合位点表现出如下的规律性, 在亚氨基类配合物中, Zn2+与腺嘌呤的N7、N6位结合比与N1、N6位结合形成的配合物更稳定; 氨基类配合物中, Zn2+以"双齿"形式与腺嘌呤异构体上的氮结合时的优先顺序为(N3和N9)>(N7和N6)>(N1和N6). 研究表明, 不论气相还是溶液相, 孤立的腺嘌呤分子内的质子转移较困难, 结合Zn2+后也不能明显降低关键步骤的活化能; 结合Cu2+却能明显地降低气相中关键步骤的活化能, 但溶剂效应却不利于Cu2+引发腺嘌呤分子内的质子转移.     

A New Fluorescent Chemosensor for Cu2+ Based on Acridine-1, 8-dione Fluorophore

合成了以吖啶为发色团,以二吡啶甲基胺为离子受体的Cu2+荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Cu2+具有良好的识别性能,同时相对于Na+, K+, Ca2+, Cd2+, Co2+, Hg2+, Mg2+, Mn2+, Ni2+, Fe3+, Zn2+, Ag+ and Pb2+.等金属离子具有良好的选择性。并研究了EDTA作用下荧光恢复性能,结果表明该化合物具有Cu2+引发的荧光开光功能。     

水溶液中对Cr~(3+)高选择性荧光化学传感器的研究

设计了一种新型的Cr3+荧光化学传感器.通过荧光光谱滴定实验研究了其对Li+,Na+,K+,Zn2+,Co2+,Ni 2+,Cu2+,Fe2+,Mn2+,Al 3+,Fe3+和Cr3+等不同金属离子的选择性识别能力,结果表明,该传感器在生理pH=7.4的HEPES中对Cr3+表现出较高的选择性,并与Cr3+形成1∶1配合物,主客体相互作用荧光猝灭的络合常数为(7.80±0.34)×103.     

均三嗪衍生物应用于Fe3+和Cu2+的选择性识别研究

合成了2,4-二甲基-6-(4’-N,N-二甲氨基苯乙烯基)-1,3,5-均三嗪(1)和2-苯乙烯基-4,6-二甲基-1,3,5-均三嗪(2)两种化合物,并对其进行了1H NMR,MS,元素分析等表征.采用吸收光谱法研究了金属离子与化合物间的相互作用,结果显示:化合物1对Fe3+和Cu2+表现出高选择性光谱响应,其最大吸收波长由393 nm分别红移至525 nm和513 nm,溶液颜色由黄色变为粉红色.化合物1与Fe3+结合形成1∶1型配合物,其结合常数为1.8×104L mol-1;与Cu2+结合形成2∶1型配合物,其结合常数为2.6×1010L mol-1.化合物2仅对Fe3+呈现显著的光谱变化,其最大吸收波长由304nm红移至357 nm,而Cu2+的加入未引起光谱明显变化,2与Fe3+亦形成1∶1型配合物,结合常数为1.0×105L mol-1.结果表明Fe3+可能与化合物1和2中三嗪N配位,而Cu2+与化合物1中甲氨基中的N配位.同时考察了其它金属离子如Li+,K+,Mg2+,Ca2+,Co3+,Ni2+,Ag+,Cd2+,Hg2+和Zn2+等离子对化合物1和2吸收光谱的影响,结果显示两者光谱均无明显变化,据此提出了高选择性Fe3+,Cu2+的识别体系.     

s区金属离子对锰(Ⅱ)配位聚合物的结构构建及性质影响

本文通过在s区金属离子(Li+,Na+,K+,Mg2+,Ca2+)存在下,2,6-吡啶二羧酸(H2pda)或2-吡啶羧酸(picH)与Mn(Ac)2.4H2O的水热合成反应,系统探讨了s区金属离子的电荷和半径对Mn(Ⅱ)配位聚合物的结构构建以及热稳定性和溶解性能的影响。合成了2个混合金属配位聚合物[Na2Mn(pda)2]n(1)和[K2Mn(pda)2]n(2),并通过红外和X-单晶衍射进行了结构表征:1属于正交系,空间群Pnna;2属于单斜系,空间群P2/n。同时应用荧光光谱测试研究了配合物1水溶液的荧光性质。     

新型荧光粉Ca2Zn4Ti16O38∶Pr3+，Na+的合成和红色长余辉性质

采用溶胶-凝胶法合成了Ca2Zn4Ti16O38:Pr3+,Na+荧光粉.通过X-射线衍射和荧光光谱表征样品的物相组成和发光性质.X射线衍射(XRD)分析表明添加适量的H3BO3作助熔剂有利于形成良好的Ca2Zn4Ti16O38晶体结构.荧光光谱表明Ca2Zn4Ti16O38:Pr3+,Na+在可见光区(450～495 nm)呈现Pr3+离子的4f→4f厂特征激发光谱以及613 nm(1D2→3H4)和644 nm(3P0→3F2)特征发射.Ca2Zn4Ti16O38:Pr3+,Na+被可见光(475 nm)激发产生的(3P0→3F2)(644 nm)红色发射呈现出极慢的衰减特性.Ca2Zn4Ti16O38:Pr3+,Na+是一种新型的可见光激发红色长余辉荧光粉.     

Theoretical study of interaction of 2,6-dithiopurine with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ metal cations

The geometries of the complexes of Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺ metal cations with different possible 2,6-dithiopurine anions (DTP) were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d, p) basis set. The interactions of the metal cations at different nucleophilic sites of various possible 2,6-dithiopurine anions were considered. It was revealed that metal cations would interact with 2,6-dithiopurine anions in a bicoordinate manner. In the gas phase, the most preferred position for the interaction of Li⁺, Na⁺, and K⁺ cations is between the N₃ and S₂ sites, while all divalent cations Be²⁺, Mg²⁺, and Ca²⁺ prefer binding between the N₇ and S₆ sites of the corresponding 2,6-dithiopurine. The influence of aqueous solvent on the relative stability of different complexes has been examined using the Tomasi’s polarized continuum model. The basis set superposition error (BSSE) corrected interaction energy was also computed for complexes. The AIM theory has been applied to analyze the properties of the bond critical points (electron densities and their Laplacians) involved in the coordination between 2,6-dithiopurine anions and the metal cations. It was revealed that aqueous solution would have significant effect on the relative stability of complexes obtained by the interaction of 2,6-dithiopurine anions with Mg²⁺ and Ca²⁺ cations. The effect of metal cations on different NH and CS stretching vibrational modes of 2,6-dithiopurine has also been discussed.     

Study of Complex Formation between N-Phenylaza-15-Crown-5 with Mg2+, Ca2+, Ag+ and Cd2+ Metal Cations in Some Binary Mixed Aqueous and Non-aqueous Solvents using the Conductometric Method

The complexation reactions between Mg²⁺, Ca²⁺, Ag⁺ and Cd²⁺ metal cations with N-phenylaza-15-crown-5 (Ph-N15C5) were studied in acetonitrile (AN)–methanol (MeOH), methanol (MeOH)–water (H₂O) and propanol (PrOH)–water (H₂O) binary mixtures at different temperatures using the conductometric method. The conductance data show that the stochiometry of all of the complexes with Mg²⁺, Ca²⁺, Ag⁺ and Cd²⁺ cations is 1:1 (L:M). The stability of the complexes is sensitive to the solvent composition and a non-linear behaviour was observed for variation of log K _f of the complexes versus the composition of the binary mixed solvents. The selectivity order of Ph-N15C5 for the metal cations in neat MeOH is Ag⁺>Cd²⁺>Ca²⁺>Mg²⁺, but in the case of neat AN is Ca²⁺>Cd²⁺>Mg²⁺>Ag⁺. The values of thermodynamic parameters (ΔH _c ^o , ΔS _c ^o ) for formation of Ph-N15C5–Mg²⁺, Ph-N15C5–Ca²⁺, Ph-N15C5–Ag⁺ and Ph-N15C5–Cd²⁺ complexes were obtained from temperature dependence of stability constants and the results show that the thermodynamics of complexation reactions is affected by the nature and composition of the mixed solvents.     

Effect of metal cations [Li+, Na+, K+, Be2+, Mg2+, and Ca2+] on the structure of 2‐(3′‐hydroxy‐2′‐pyridyl)benzoxazole: A theoretical investigation

Density functional theory calculations were performed at the B3LYP/6‐311++G(d,p) level to systematically explore the geometrical multiplicity and binding strength for the complexes formed by alkaline and alkaline earth metal cations, viz. Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺ (Mⁿ⁺, hereinafter), with 2‐(3′‐hydroxy‐2′‐pyridyl)benzoxazole. A total of 60 initial structures were designed and optimized, of which 51 optimized structures were found, which could be divided into two different types: monodentate complexes and bidentate complexes. In the cation‐heteroatom complex, bidentate binding is generally stronger than monodentate binding, and of which the bidentate binding with five‐membered ring structure has the strongest interaction. Energy decomposition revealed that the total binding energies mainly come from electrostatic interaction for alkaline metal ion complexes and orbital interaction energy for alkaline earth metal ion complex. In addition, the electron localization function analysis show that only the Be? O and Be? N bond are covalent character, and others are ionic character. © 2012 Wiley Periodicals, Inc.     

Effect of ring annelation on cations [M = H+, Li+, Na+, K+, Be2+, Mg2+, and Ca2+]…benzene interaction: A density functional theory investigation

Density functional theory calculation was carried out on cation‐π complexes formed by cations [M = H⁺, Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺] and π systems of annelated benzene. The cation‐π bonding energy of Be²⁺ or Mg²⁺ with annelated benzene is very strong in comparison with the common cation‐π intermolecular interaction, and the bonding energies follow the order Be²⁺ > Mg²⁺ > Ca²⁺ > Li⁺ > Na⁺ > K⁺. Similarly, the interaction energies follow the trend 1‐M < 2‐M < 3‐M for all the metal cations considered. These outcomes may be due to the weak interactions of the metal cations with C? H and the interactions of metal cations with π in addition to the nature of a metal cation. We have also investigated on all the possible substituted sites, and find that the metal ion tends to interact with all ring atoms while proton prefers to bind covalently to one of the ring carbons. The binding of metal cations with annelated benzenes has striking effect on nuclear magnetic resonance chemical shifts using the gauge independent atomic orbital method. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

Molecular structure and bonding character of mono and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+, and Ca2+) with substituted benzene derivatives: AIM,NBO, and NMR analyses

Cation–π complexes between several cations (Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺) and different π-systems such as para-substituted (F, Cl, OH, SH, CH₃, and NH₂) benzene derivatives have been investigated by UB3LYP method using 6-311++G** basis set in the gas phase and the water solution. The ions have shown cation–π interaction with the aromatic motifs. Vibrational frequencies and physical properties such as dipole moment, chemical potential, and chemical hardness of these compounds have been systematically explored. The natural bond orbital analysis and the Bader’s quantum theory of atoms in molecules are also used to elucidate the interaction characteristics of the investigated complexes. The aromaticity is measured using several well-established indices of aromaticity such as NICS, HOMA, PDI, FLU, and FLUπ. The MEP is given the visual representation of the chemically active sites and comparative reactivity of atoms. Furthermore, the effects of interactions on NMR data have been used to more investigation of the studied compounds.     

ESI‐MS studies of the non‐covalent interactions between biologically important metal ions and N‐sulfonylcytosine derivatives

The aim of this report is to present the electrospray ionization mass spectrometry results of the non‐covalent interaction of two biologically active ligands, N‐1 ‐ (p‐toluenesulfonyl)cytosine, 1‐TsC, 1 and N‐1 ‐ methanesulfonylcytosine, 1‐MsC, 2 and their Cu(II) complexes Cu(1‐TsC‐N3)₂Cl₂, 3 and Cu(1‐MsC‐N3)₂Cl₂ and 4 with biologically important cations: Na⁺, K⁺, Ca²⁺, Mg²⁺ and Zn²⁺. The formation of various complex metal ions was observed. The alkali metals Na⁺ and K⁺ formed clusters because of electrostatic interactions. Ca²⁺ and Mg²⁺ salts produced the tris ligand and mixed ligand complexes. The interaction of Zn²⁺ with 1–4 produced monometal and dimetal Zn²⁺ complexes as a result of the affinity of Zn²⁺ ions toward both O and N atoms. Copyright © 2016 John Wiley & Sons, Ltd.     

A Thermodynamic Study Between 18-Crown-6 with Mg2+, Ca2+, Sr2+and Ba2+ Cations in Water–Methanol and Water–Ethanol Binary Mixtures Using The Conductometric Method

The complexation reactions between Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ cations with the macrocyclic ligand, 18-Crown-6 (l8C6) in water–methanol (MeOH) binary systems as well as the complexation reactions between Ca²⁺ and Sr²⁺ cations with 18C6 in water–ethanol (EtOH) binary mixtures have been studied at different temperatures using conductometric method. The conductance data show that the stoichiometry of all the complexes is 1:1. It was found that the stability of 18C6 complexes with Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ cations is sensitive to solvent composition and in all cases, a non-linear behaviour was observed for the variation of log K _f of the complexes versus the composition of the mixed solvents. In some cases, the stability order is changed with changing the composition of the mixed solvents. The selectivity order of 18C6 for the metal cations in pure methanol is: Ba²⁺ > Sr²⁺ > Ca²⁺ > Mg²⁺. The values of thermodynamic parameters (Δ H _c ° and Δ S _c °) for formation of 18C6–Mg²⁺, 18C6–Ca²⁺, 18C6–Sr²⁺ and 18C6–Ba²⁺complexes were obtained from temperature dependence of the stability constants. The obtained results show that the values of (Δ H _c ° and Δ S _c °) for formation of these complexes are quite sensitive to the nature and composition of the mixed solvent, but they do not vary monotonically with the solvent composition.This revised version was published online in July 2005 with a corrected issue number.     

Theoretical study on the interaction of glutathione with group IA (Li+, Na+, K+), IIA (Be2+, Mg2+, Ca2+), and IIIA (Al3+) metal cations

The structures and energies of complexes obtained upon interaction between glutathione (GSH) and alkali (Li⁺, Na⁺, K⁺), or alkaline earth metal (Be²⁺, Mg²⁺, Ca²⁺), or group IIIA (Al³⁺) cations were studied using quantum chemical density functional theory. The characteristics of the interactions between GSH and the metal cations at different nucleophilic sites of GSH were examined selecting systematically, both mono- and multi-coordinating were taken into account. The results indicated that the heteroatom of GSH, the radius and charge of metal ion, and the coordination number of the metal cation with the ligand played important roles in determining the stability of these complexes. Moreover, the intramolecular hydrogen migration in GSH could be promoted by the metal cations during coordination reaction. Furthermore, the Al³⁺ cation might catalyze the decarboxylation reaction and stimulate the formation of covalent bond between S atom and adjacent O atom of GSH.     

Untersuchung der Komplexierung von Na+, K+, Ca2+ und Ba2+ mit einigen elektrisch neutralen Liganden durch Messung von 13C-chemischen Verschiebungen und Spin-Gitter-Relaxationszeiten

Investigation of the complexing of Na⁺, K⁺, Ca²⁺ and Ba²⁺ with some uncharged ligands by ¹³C-chemical shift and spin-lattice relaxation time measurements The influence of Na⁺, K⁺, Ca²⁺ and Ba²⁺ ions on ¹³C chemical shifts and on spin-lattice relaxation times of some electrically neutral ion carriers was investigated. In the solvents CD₃CN and CD₃OD and in presence of an excess of metal ions ligand 4 (see the Scheme) forms complexes of 1:1 stoichiometry. All four oxygen atoms of the ligand as well as solvent molecules take part in the coordination. In CDCl₃ as solvent, for all ions investigated except sodium, only 1:2 complexes (metal/ligand) were observed with 4 . Sodium ions form both 1:1 and 1:2 complexes in this solvent. In the 1:2 complexes of the investigated monovalent ions only one, in those of the divalent ions both amide carbonyl groups of ligand 4 take part in the coordination.     

Study of Complex Formation Between Dicyclohexano-18-Crown-6 (DCH18C6) with Mg 2+, Ca2+, Sr 2+, and Ba2+ Cations in Methanol–Water Binary Mixtures Using Conductometric Method

The complexation reactions between Mg²⁺,Ca²⁺,Sr²⁺ and Ba²⁺ metal cations with macrocyclic ligand, dicyclohexano-18-crown-6 (DCH18C6) were studied in methanol (MeOH)–water (H₂O) binary mixtures at different temperatures using conductometric method . In all cases, DCH18C6 forms 1:1 complexes with these metal cations. The values of stability constants of complexes which were obtained from conductometric data show that the stability of complexes is affected by the nature and composition of the mixed solvents. While the variation of stability constants of DCH18C6-Sr ²⁺ and DCH18C6-Ba²⁺versus the composition of MeOH–H₂O mixed solvents is monotonic, an anomalous behavior was observed for variations of stability constants of DCH18C6-Mg²⁺ and DCH18C6-Ca²⁺ versus the composition of the mixed solvents. The values of thermodynamic parameters (ΔH_c°, ΔS_c°) for complexation reactions were obtained from temperature dependence of formation constants of complexes using the van’t Hoff plots. The results show that in most cases, the complexation reactions are enthalpy stabilized but entropy destabilized and the values of thermodynamic parameters are influenced by the nature and composition of the mixed solvents. The obtained results show that the order of selectivity of DCH18C6 ligand for metal cations in different concentrations of methanol in MeOH–H₂O binary system is: Ba²⁺>Sr²⁺>Ca²⁺> Mg²⁺.