一种新型黄酮冠醚及其对碱金属和碱土金属离子的配位作用

介绍了一种新型黄酮冠醚(FC)的合成,并研究了这种冠醚与碱金属和碱土金属高氯酸盐发生配位作用时的吸收光谱和荧光光谱的变化,通过不同的处理方法求出了该冠醚与几种离子配位的稳定常数.     

Lipophilic Diamides as Ionophores for Alkali and Alkaline Earth Metal Cations

A series of lipophilic N, N, N′,N′-tetrasubstituted diamides were prepared and their selectivity in solvent polymeric membranes was studied, cis-N, N, N′, N′-Tetraisobutylcyclohexane-1,2-dicarboxamide induces a selectivity in membranes for Li⁺over alkaline earth metal cations and other alkali metal cations by a factor of about 1000 and 100 respectively. The ionophore N, N′-diheptyl-N,N′-dimethylethylmalonamide is an attractive candidate for the use in microelectrodes for the determination of intracellular Mg²⁺-activities.     

Ion-selective Dyes for the Complexation of Alkali and Alkaline Earth Cations

Abstract

The interactions of ion-selective dyes with alkali and alkaline earth cations in methanol have been investigated quantitatively. Both dyes examined are able to complex these cations selectively. From the spectral changes the stability constants of the complexes formed are calculated. The substituents at the nitrogen atoms of the diaza crown ethers obviously influence the stability of the complexes.     

Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

CuS is a unique semiconductor with potential in optoelectronics. Its unusual electronic structure, including a partially occupied valence band, and complex crystal structure with an S−S bond offer unique opportunities and potential applications. In this work, the use of doping to optimize the properties of CuS for various applications is investigated by density functional theory (DFT) calculations. Among the dopants studied, Ni, Zn, and Mg may be the most practical due to their lower formation energies. Doping with Fe, Ni, or Ca induces significant distortion, which may be beneficial for achieving materials with high surface areas and active states. Significantly, doping alters the conductor-like behavior of CuS, opening a band gap by increasing bond ionicity and reducing the S−S bond covalency. Thus, doping CuS can tune the plasmonic properties and transform it from a conductor to an intrinsic fluorescent semiconductor. Ni and Fe doping give the lowest band gaps (0.35 eV and 0.39 eV, respectively), while Mg doping gives the highest (0.86 eV). Doping with Mg, Ca, and Zn may enhance electron mobility and charge separation. Most dopants increase the anisotropy of electron-to-hole mass ratios, enabling device design that exploits directional-dependence for improved performance.     

Selectivity of Low- and High-Silica Clinoptilolites with Respect to Alkali and Alkaline–Earth Metal Cations

The ion-exchange equilibria involving K⁺ and Ca²⁺ cations were studied using the Na-forms of nine different clinoptilolite samples. The high-silica (in the native state, sodium–potassium form) clinoptilolites were shown to have the increased selectivity with respect to K⁺ ions, whereas the low-silica (in the native state, calcium form) clinoptilolites to Ca²⁺ ions. The phenomenon found is interpreted as a structural memory of clinoptilolites with respect to alkali and alkaline-earth metal ions which had been present during zeolite crystallization under natural conditions.     

Potentiometric Selectivities of Dibenzo-16-crown-5 Compounds for Alkali and Alkaline Earth Metal Cations and Ammonium Ions

Potentiometric selectivities toward alkali and alkaline earth metal cations and ammonium ions are utilized to probe the complexation of these cationic species by dibenzo-16-crown-5 lariat ethers. Attachment of one or two pendant groups to the central carbon of the three-carbon bridge in dibenzo-16-crown-5 markedly alters the potentiometric responses of the ionophores when incorporated in solvent polymeric membrane electrodes. Results obtained for dibenzo-16-crown-5 compounds with coordinating side arms containing ether, carboxylic acid, ester, and amide groups provide insight into the role of the side arm in metal ion complexation by lariat ether compounds.     

Directional Preferences of Ether O-Atoms Towards Alkali and Alkaline Earth Cations

An analysis of the environments of alkali and alkaline earth cations complexed to ethers has been made with the Cambridge Structural Database. The cations invariably lie close to the bisecting plane through the O-atoms. The larger cations show an apparent preference to approach the ether group along a tetrahedral lone pair direction, whereas Li⁺ cations tend to be found along the C? O? C bisector, i.e., along the trigonal lone pair direction. These observations are discussed in relation to recent theoretical and experimental findings.     

Tetra(diethyl)amide-p-tert-butyl-thiacalix[4]arene in Cone Conformation: Synthesis and Binding Properties with Alkali,Alkaline Earth,Heavy and Transition Metal Ions

Tetra(diethyl)amide-p-tert-butylthiacalix[4]arene 1a in the cone conformation was synthesized and its binding properties towards a large variety of metal ions were established on the basis of liquid–liquid and solid–liquid extraction as well as complexation experiments. This compound is a less efficient and selective compound than the “classical” tetra(diethyl)amide-p-tert-butylcalix[4]arene 3 in the cone conformation for alkali and alkaline earth metal ions. However, Pb²⁺ is selectively extracted and complexed within heavy and transition metal ions.     

Preparation of Neutral Ionophores for Alkali and Alkaline Earth Metal Cations and their application in ion selective membrane electrodes

The preparation of a series of non-cyclic, uncharged ligands able to selectively complex alkali and alkaline earth metal cations is described. These molecules are designed to be used as carriers for cations through membranes. Some of the compounds show high Ca²⁺ and Na⁺ selectivity, respectively, in liquid membrane electrodes.     

Lipophilic Di- and Triamides as Ionophores for Alkaline Earth Metal Cations

Different electrically neutral lipophilic di- and triamides were prepared and their ion selectivity in membranes studied. In membranes the ionophore N, N′-diheptyl-N, N′-dimethyl-succinamide prefers Ca²⁺ over Mg²⁺ by a factor of 20 but rejects Na⁺ and K⁺ in respect to Mg²⁺ by a factor of 100 and 10, respectively. This selectivity suffices to perform useful intracellular Mg²⁺ activity studies.     

New Fluorophores Based on Non-Cyclic Crown Ethers for Alkali and Alkaline Earth Metal Cation

Recent advances regarding podand derivatives which are non-cyclic crown ethers incorporating functional groups have been reviewed. Particular attention has been paid to fluorophore appended non-cyclic crown ethers as sensors for cation detection. Their complexation behavior with alkali and alkaline earth cations and interactions between their terminal groups is also discussed in detail.     

谷氨酰胺与碱金属及碱土金属离子络合物的构象和金属离子亲和势：第一性原理研究

Conformations and reaction energetics are important for understanding the interactions be-tween biomolecules and metal ions. In this work, we report a systematic ab initio study on the conformations and metal ion affinities of glutamine (Gln) binding with alkali and alkaline earth metal ions. An efficient and reliable method of searching low energy conformations of metalated Gln is proposed and applied to the complexes of Gln.M^+/++ (M^+/++=Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、Be⁺⁺、Mg⁺⁺、Ca⁺⁺、Sr⁺⁺和Ba⁺⁺). In addition to all conformers known in literatures, many new important conformations are located, demonstrating the power of the new method and the necessity of the conformational search performed here. The metal coordination modes, relative energies, dipole moments, and equilibrium distribu-tions of all important conformations of Gln.M^+/++ are calculated by the methods of B3LYP, BHandHLYP, and MP2. IR spectra and metalation enthalpies and free energies are also pre-sented and compared with the available experiments. The results form an extensive database for systematic examination of the metalation properties of Gln.     

Thermodynamic Properties of Ammonia Production from Hydrogenation of Alkali and Alkaline Earth Metal Amides

Thermodynamic properties of alkali and alkaline earth metal amides are critical for their performance in hydrogen storage as well as catalytic ammonia synthesis. In this work, the ammonia equilibrium concentrations of LiNH₂, KNH₂ and Ba(NH₂)₂ at ca.10 bar of hydrogen pressure and different temperatures were measured by using a high-pressure gas-solid reaction system equipped with a conductivity meter. Hydrogenation of KNH₂ gives the highest ammonia equilibrium concentration, followed by Ba(NH₂)₂ and LiNH₂. Based on these data, the entropy and enthalpy changes of the reaction of ANH₂+H₂→AH+NH₃ (A=Li, K, and Ba) were obtained from the van't Hoff equation. These thermodynamic parameters provide important information on the understanding of metal amides in catalytic ammonia synthesis reaction.     

Complexation and Transport of Alkali and Alkaline Earth Metal Cations by p-tert-Butyldihomooxacalix[4]arene Tetraketone Derivatives

The binding properties of three p-tert-butyldihomooxacalix[4]arene tetraketone derivatives (tert-butyl 2b, adamantyl 2c and phenyl 2d) in the cone conformation and one derivative (methyl 2a) in a partial cone conformation, towards alkali and alkaline earth metal cations have been established by extraction studies of metal picrates from water into dichloromethane, stability constant measurements in methanol and acetonitrile, and by ¹H NMR spectrometry. Transport experiments of metal picrates through a dichloromethane membrane were also performed. The results are compared to those obtained with closely-related calix[n]arene derivatives (n = 4 and 5) and discussed in terms of the substituents, size and conformational effects. Methylketone 2a is a poor binder for all the cations studied, due to its partial cone conformation. Ketones 2b, 2c and 2d show high extraction and complexation levels for the alkali cations, with similar profiles and preference for K⁺ and Na⁺ (plateau selectivity). Towards alkaline earth cations, these ketones show a strong peak selectivity for Ba²⁺ in extraction, but a plateau selectivity for Ca²⁺, Sr²⁺ and Ba²⁺ in complexation. The nature of the substituent attached to the ketone function has some influence on their binding properties, with phenylketone 2d being a slightly weaker binder than ketones 2b and 2c. ¹H NMR titrations confirm the formation of 1:1 complexes between the ketones and the cations studied, also indicating that they should be located inside the cavity defined by the phenoxy and carbonyl oxygen atoms. Ketones 2b, 2c and 2d show transport rates that do not follow, in general, the same trends observed in extraction and complexation.     

碱金属及碱土金属离子化合物溶解性变化规律

对碱金属、碱土金属离子化合物的溶解性与正负离子半径差Δr的变化关系进行了探讨,总结出碱金属、碱土金属同族化合物溶解性随Δr的变化有以下3种情况:(1)随Δr增大,溶解度s随之增大;(2)随Δr增大,s反而减小;(3)随Δr增大,s变化不规则。在此基础上,通过碱金属、碱土金属同族化合物晶格能U、离子水合焓ΔHh、溶解过程的焓变ΔHs和自由能变ΔGs等热力学量的递变对其溶解性随Δr的变化作出了解释。     

Investigation on Mechanism for Separation of Alkali, Alkaline Metal and Ammonium Cations in Nonaqueous Capillary Electrophoresis

Capillary electrophoresis ( CE ) has rapidly gained great interests among researchers in many different fields. One of these areas is the separation of small ions such as inorganic cations, anions, and low Mr organic molecules However, as the separation of ions     

Lipophilic Amides of EDTA,NTA and Iminodiacetic Acid as Ionophores for Alkaline Earth Metal Cations

A series of electrically neutral lipophilic di-, tri-, and tetra-amides containing tertiary-amine N-atoms were prepared in order to investigate their selectivity for alkali and alkaline earth metal cations in solvent polymeric membranes. Considerable selectivity changes were observed for membranes incorporating certain of these ligands as compared with ligand-free membranes. A 1:1 cation/ligand complex was isolated from N, N′, N″-triheptyl-N, N′, N″-trimethyl-nitrilotriacetamid and Mg (SCN)₂ whereas with Ca (SCN)₂ the corresponding 2:3 cation/ligand complex was formed. N, N′, N″, N?, N?-tetramethyl-ethylenediaminetetraacetamide yields a 1:1 cation/ligand complex with Mg (SCN)₂.     

Synthesis and Crystal Structures of Alkali and Alkaline Earth Metal Complexes of 3,5-Dinitropyrazolyl-4-carboxylate

The synthesis and crystal structures of 3,5-dinitro-1H-pyrazolyl-4-carboxylic acid (H₂dnpzc) and its four complexes with Ca²⁺, Ba²⁺, Na⁺ and K⁺ are reported in this paper. Ca(dnpzc) · 5H₂O exhibits a 1D polymeric structure, whereas Ba(dnpzc) · 4H₂O possesses a 2D structure. The structure of Na₂(dnpzc) · 4H₂O consists of 2D layers of [Na(dnpzc)]^–_n and 1D chains of [Na(H₂O)₃]⁺_n. K₂(dnpzc) · H₂O has a true 3D structure. It was observed that the doubly deprotonated ligand (dnpzc^2–) can act as a versatile bridge to form polymeric structures by varying combinations of its 8 potential donor atoms (two carboxy O atoms, two pyrazolyl N atoms and four nitro O atoms). Particularly in the structure of K₂(dnpzc) · H₂O, all the 8 donor atoms of dnpzc^2– take part in the coordination and as many as 10 potassium atoms are connected by one ligand.