五元瓜环与钕离子在四氯酸锌离子诱导下构筑的配合超分子自组装

在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn2+容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。     

五元瓜环与钕离子在四氯酸锌离子诱导下构筑的配合超分子自组装

在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn²⁺容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。     

The Diffusion of Ferricyanide Through Perfluorinated Ionomer (Nafion) Membranes

The diffusion coefficient for ferricyanide anion in perfluorinated ionomer films (Nafion) have been measured. They are low enough to permit the use of ferricyanides to detect the presence of defects in such films.     

Development of a chiral host system tunable via changes in a 21-column packing structure

A tunable chiral host system was developed by the self-assembly of a chiral 2₁-column structure formed from (1R,2R)-1,2-diphenylethylenediamine and dicarboxylic acid. This host system can include guest molecules by changing the packing of a chiral 2₁-column enantioselectively.     

Synthesis, crystal structure and spectroscopic properties of two new complexes containing azido or dicyanamido bridges

Two new complexes, [Cu(L₁){N(CN)₂}]·ClO₄ (1) (L₁ is 1,8-dimethyl-1,3,6,8,10,13-hexa-azacyclotetradecane) and [Co(L₂)(N₃)₂]·ClO₄ (2) (L₂ is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane) have been synthesized and characterized. The compounds crystallize in the monoclinic system P2₁ space group for 1 and P2₁/n for 2. Single crystal X-ray analysis reveals that the compound 1 assumes a one-dimensional structure via hydrogen-bonding interactions, in which each Cu(II) ion is coordinated by four nitrogen atoms from ligand L₁ and one nitrogen atom from [N(CN)₂]⁻ anion. For compound 2, each Co(III) ion is coordinated by four nitrogen atoms of ligand L₂ and two nitrogen atoms from N₃ ⁻ anion.     

Cation and anion coordination chemistry of palladium(II) with polyazacycloalkanes. Thermodynamic and structural studies

The interaction of PdCl ₄ ^2– with the macrocyclic ligands of the series [3k]aneN _k has been studied both in solution and in the solid state. [18]aneN₆ and [21]aneN₇ form both mono- and binuclear Pd²⁺ complexes, whose stability constants have been determined in 0.5 mol dm^–3 NaCl at 298.15 K. [21]aneN₇ also forms, in solution, a trinuclear species in which an amino group deprotonates to bridge two Pd²⁺ ions, as observed in the solid state. The crystal structure of the complexes [Pd₂([18]aneN₆)Cl₂][ClO₄]₂ and [Pd₃([21]aneN₇)Cl₃][ClO₄]₂ · H₂O have been solved by single crystal X-ray analysis. C₁₂H₃₀N₆Cl₄O₈Pd₂: monoclinic, space group C2/m,a = 10.876(2),b = 18.117(2),c = 7.043(2) Å, = 113.78(2)°,V = 1270(12) ų,Z = 2,D _calc = 1.92 g cm^-3, = 16.94 cm^–1.R = 0.063,R _w = 0.059. C₁₄H₃₆N₇CI₅O₉Pd₃: orthorhombic, space groupPcab,a = 13.125(7),b = 13.213(3),c = 33.570(5) Å,V = 5822(3) ų,Z = 8,D _calc = 2.15 g cm^–3, = 21.20 cm^–1.R = 0.074,R _w = 0.061. In very acidic solutions the polyammonium cations (H _k [3k]aneN _k ) ^k+ interact with PdCl ₄ ^2– forming second sphere coordinated species. These reactions have been followed by a microcalorimetric technique in 2 mol dm^–3 HCl solutions. The slowness of the reactions of (H₁₀[30]aneN₁₀)¹⁰⁺ with PdCl ₄ ^2– has been interpreted in terms of inclusion of the anion into the receptor's cavity as shown by the crystal structure of [(PdCl₄)(H₁₀[30]aneN₁₀)][PdCl₄]₂Cl₄: triclinic, space group PT,a = 7.760(3),b = 11.448(4),c = 13.399(11) Å, = 96.31(8)°, = 104.50(6)°, = 92.30(3)°,Z = 1.R = 0.046 andR _w = 0.039.This paper is dedicated to the memory of the late Dr C. J. Pedersen.     

化学位移估算研究ATP构象随溶液pH值的变化

利用Johnson和Bovey的理论和方法计算了不同扭曲角χ(O4′－C1′－N9－C4)的ATP(5′-三磷酸腺苷)分子中糖环质子H1′和H2′由于环流效应引起的化学位移.H1′的化学位移与扭曲角χ有较强的依赖关系,反映了ATP在溶液中细微的构象变化.将计算结果与实验结果比较,证明在本文讨论的pH值范围(1～10)内,Mg2＋加入后,ATP的扭曲角χ在230～360°范围内变化.随溶液的pH值减小,ATP分子的构象由trans 构象通过-gauche构象转变为cis构象. 从而证明在酸性条件下, ATP倾向于以cis构象存在,而在碱性条件下trans构象更为稳定,从另一方面支持了在酸性条件下N1参与配位而在碱性条件下N7参与配位的结论.在讨论中也考虑了由pH变化所引起的环流强度的变化.     

Partial molar volumes and partial molar adiabatic compressibilities of ethylenediamine complexes in water

Densities and ultrasonic propagating velocities of aqueous solutions of ethylenediamine complexes [Co(en)₃]Cl₃, [Cr(en)₃]Cl₃, [Ni(en)₃]Cl₂, and [Cu(en)₂]Cl₂ (en=ethylenediamine), as well as the ligand ethylenediamine were measured at 25°C. The infinite dilution values of the partial molar volume V ₂ ⁰ and partial molar adiabatic compressibility K _s ⁰ were evaluated. The value of K _s ⁰ of the ligand ethylenediamine is nearly zero. The values of V ₂ ⁰ and K _s ⁰ are combined with other interaction parameters, such as the Stokes radii and the viscosity B-coefficients, and their dependece upon the charge number and the stereochemistry of the complex ions is discussed.     

Complex compounds of tetracycline with WO 4 2− and MoO 4 2− ions. Investigation by pH-metric and conductometric methods

By using pH-metric and conductometric methods it has been found that tetracycline (H₃TC) forms with WO ₄ ^2– and MoO ₄ ^2– ions the following complex compounds: [WO₃HTC]^2–, [WO₃(H₂TC)₂]^2– and [MoO₃(H₂TC)₂]^2–. Stability constants log/gb ₁ ^k =7.86 and log ₁ ^k =7.80 for [WO₃HTC]^2– and [MoO₃HTC]^2–, respectively, have been calculated from pH-metric measurements.     

Synthesis,characterization and luminescence of the tetranuclear gold cluster: [Au4{7,8-(PPh2)2-7,8-C2B9H10}2(PPh3)2]

A tetranuclear gold cluster has been synthesized by the reaction of [Au(PPh₃)NO₃] with the closo carborane diphosphine 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀ in THF, and characterized by elemental analysis, FT-IR, ¹H and ¹³C?NMR spectroscopy and X-ray structure determination. The cluster crystallizes in the triclinic Pī, a?=?15.118(8)?Å, b?=?16.057(9)?Å, c?=?24.284(13)?Å, α?=?80.822(9)°, β?=?79.624(8)°, γ?=?81.938(8)°, Z?=?2, R ₁?=?0.0626, wR ₂?=?0.1894. A single crystal structure determination showed that four gold atoms form a tetrahedral framework. Among these four gold atoms, two were chelated by two nido carborane diphosphine [7,8-(PPh₂)₂-7,8-C₂B₉H₁₀]^? anions coming from the degradation of the initial closo ligand 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀, while the other two were ligated to two PPh₃ groups. The luminescence of this cluster was also investigated in dichloromethane solution at room temperature.     

Assembly of three supramolecular compounds based on [P2Mo5O23]6− and Ni(II) complexes

Three supramolecular compounds based on [P₂Mo₅O₂₃]^6? and Ni(II)–bim, [Ni(bim)₃]₃[P₂Mo₅O₂₃]·2H₂O (1), [Ni(Hbim)(bim)₂]₄[P₂Mo₅O₂₃]₂·3H₂O (2), and [Ni(bim)(Hbim)(phen)]₂[P₂Mo₅O₂₃]·7H₂O (3) (bim?=?2,2′-biimidazole, phen?=?1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction, IR, and TG. All the compounds show 3-D supramolecular networks constructed from weak interactions among free Ni(II) complex, water, and oxygens of [P₂Mo₅O₂₃]^6?. Compound 3 represents the first supramolecular example integrating {Ni(bim)(Hbim)(phen)} with Strandberg-type phosphomolybdate. The compounds display good electrocatalytic activity to reduce hydrogen peroxide and intense fluorescence properties in solution at room temperature.     

Intensity distribution in the vibronic Γ7(2 T 2g )→Γ8(4 A 2g ) transition of ReBr 6 2− in Hexahalogenostannate host crystals

The phosphorescence spectra of ReBr ₆ ^2– doped A₂SnX₆ (A = K, Rb, Cs; X = Cl, Br) have been measured at 10 K. The spectra consist of a weighted sum of progressions associated with the local modes of the ReBr ₆ ^2– center. By a fit to a generalized Lorentzian line shape function the totally symmetric distortion of the ₇(² T _2g ) excited state relative to the ₈(⁴ A _2g ) ground state has been determined.Dedicated to Professor Dr. H.-H. Schmidtke on the occasion of his 50th birthday.     

Theoretical study of the triplet excited state of PtPOP and the exciplexes M-PtPOP (M = Tl, Ag) in solution and comparison with ultrafast X-ray scattering results

The [Pt₂(H₂P₂O₅)₄]⁴⁻ ions in the ground and excited states and the excited-state complexes M-[Pt₂(H₂P₂O₅)₄]³⁻ and M₂-[Pt₂(H₂P₂O₅)₄]²⁻ (M = Ag, Tl) were studied in solution with various density functional theory (DFT) functionals from Gaussian 09 and Amsterdam Density Functional (ADF) programs. Calculated results were compared with ultrafast X-ray solution scattering data. Time dependent DFT (TD-DFT) calculations with the B3PW91 functional and unrestricted open shell calculations with the mPBE functional produce good agreement with the experimental results. Compared to gas phase calculations, the surrounding solvent is found to play an important role to shorten the Pt-Pt and M-Pt (M = Ag, Tl) bond lengths, lowering the molecular orbital energies and influences the molecular orbital transitions upon excitation, which stabilizes the excited transient molecules in solution.     

Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

By reacting [{Cp‴Fe(CO)₂}₂(µ,η^1:1-P₄)] (1) with in situ generated phosphenium ions [Ph₂P][A] ([A]⁻ = [OTf]⁻ = [O₃SCF₃]⁻, [PF₆]⁻), a mixture of two main products of the composition [{Cp‴Fe(CO)₂}₂(µ,η^1:1-P₅(C₆H₅)₂)][PF₆] (2a and 3a) could be identified by extensive ³¹P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η^4:1-P₅Ph₂){Cp‴(CO)₂Fe}][PF₆] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)₂}₄(µ₄,η^1:1:1:1-P₈)][OTf]₂ (5) containing a tetracyclo[3.3.0.0^2,7.0^3,6]octaphosphaoctane ligand.     

Solid substrate-room temperature phosphorimetry for the determination of trace protein using ion association complex [Cu(BPY)2]·[(Fin)2] as a phosphorescent probe

Fluorescein (HFin) emitted strong and stable room temperature phosphorescence (RTP) on filter paper after set at 50 °C for 10 min using Li⁺ as the ion perturber. HFin existed as Fin⁻ when the pH value was in the range of 5.45–7.36. Fin⁻ could react with [Cu(BPY)₂]²⁺ (BPY: α,α-bipyridyl) to produce ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻, which could enhance the RTP signal of Hfin. In the presence of bovine serum albumin (BSA), the –COOH group of Fin⁻ in the [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ could react with the –NH₂ group of BSA to form the ion association complex [Cu(BPY)₂]²⁺·[(Fin-BSA)₂]²⁻, which contained –CO–NH– bond. This complex could sharply enhance the RTP signal of Hfin and the ΔI_p was directly proportional to the content of BSA. According to the facts above, a new solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace protein had been established using the ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻as a phosphorescent probe. This method had wide linear range (0.40 × 10⁻⁹–280 × 10⁻⁹ mg l⁻¹), high sensitivity (the detection limit (LD) was 1.4 × 10⁻¹⁰ mg l⁻¹), good precision (RSD: 3.4–4.9%) and high selectivity (the allowed concentration of coexistent ions or coexistent materials was high). It had been applied to the determination of the content of protein in 10 kinds of real samples, and the result agreed well with pyrocatechol violet-Mo (VI) method (P.V.M.M.), which indicated it had high accuracy. Meanwhile, reaction mechanism for the determination of trace protein with [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ phosphorescent probe was also discussed. The academic thought of this research could not only be used to develop many kinds of ion association complex phosphorescent probes, but also provided a new way to promote the sensitivity of SS-RTP.     

Synthesis and peroxidase-like mimic study in H2O2 detection of a stable polyoxometalate-pillared coordination polymer

Abstract

A stable hamburger-like polyoxometalate (POM)-pillared coordination polymer (CP) [Ag₁₅(trz)₁₀][SiW₁₂O₄₀] (Ag₁₅SiW₁₂) (trz = 1,2,3-triazole) has been synthesized and characterized. Single crystal X-ray diffraction (SCXRD) analysis indicates that SiW₁₂ polyanions are sandwiched between adjacent Ag-trz sheets with two distinct types of pores, giving a three-dimensional POM-pillared sheet framework. Inspired by the reported horseradish peroxidase (HRP) and other enzyme mimics, the peroxidase-like activity of Ag₁₅SiW₁₂ was investigated to catalyze oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H₂O₂. Compared with other POM-involved enzyme mimics, Ag₁₅SiW₁₂ exhibits excellent peroxidase-like activity. Detection of H₂O₂ was also studied in buffer solution, and the result shows broader application range (1–100?μM), faster response time (1?min) and lower detection limit (0.27?μM), which may be ascribed to the distinct structure and maximized synergistic effect of individual components.

     

Electrochemical properties of <Emphasis Type="Italic">n</Emphasis>-sulfonatothiacalyx[4]arene complexes with Fe<Superscript>3+</Superscript> and [Co(dipy)<Subscript>3</Subscript>]<Superscript>3+</Superscript> ions

The electrochemical properties of n-sulfonatothiacalyx[4]arene (H₄XNa₄) complexes with [Co(dipy)₃]³⁺ and Fe³⁺ ions were studied by means of cyclic voltammetry in aqueous solution at pH 2.5. The observed single-electron reduction of [Co(dipy)₃]³⁺ bound extraspherically to the upper rim and Fe³⁺ ion bound intraspherically to the lower rim of n-sulfonatothiacalyx[4]arene in binary [Co(dipy)₃]³⁺ · H₃X^5?, H₃X^5? · Fe³⁺, and ternary [Co(dipy)₃]³⁺ · H₃X^5? · Fe³⁺ heterometal complexes was more difficult than in the free state. The reversible single-electron transfer to the metal ion results in lower binding energy ([Co(dipy)₃]³⁺, ΔΔG ₀ = 3.9 kJ/mol) or in full fast dissociation of the complex (Fe³⁺). The ternary complex in the solution forms the aggregates, in which inner encapsulated Fe(III) and Co(III) ions are not reduced on the electrode. Their quantitative reduction takes place by the relay mechanism of intra- and intermolecular electron transfer through electrochemically generated [Co(dipy)₃]²⁺ outer ions.     

Potentiometric flow injection determination of manganese(II) by using a hexacyanoferrate(III)-hexacyanoferrate(II) potential buffer

A highly sensitive potentiometric flow injection analysis method for the determination of manganese(II), utilizing a redox reaction with hexacyanoferrate(III) in near neutral media containing ammonium citrate is described. The analytical method is based on the detection of the change in potential of a flow-through type redox electrode detector, resulting from the composition change of an [Fe(CN)₆]³⁻-[Fe(CN)₆]⁴⁻ potential buffer solution. A linear relationship between the potential change (peak height) and the concentration of manganese(II) was found. Manganese(II) in a wide concentration range from 10⁻⁴ to 10⁻⁷ M could be determined by appropriately altering the concentration of the potential buffer from 10⁻³ to 10⁻⁵ M. The lower detection limit of manganese(II) was determined to be 1×10⁻⁷ M. The sampling rate and relative standard deviation were 20 h⁻¹ and 1.9% (n=8) for 6×10⁻⁶ M manganese(II), respectively. The proposed method was successfully applied to the determination of manganese(II) in actual soil samples obtained from tea fields. Analytical results obtained by the proposed method were in good agreement with those obtained by an atomic absorption spectrophotometric method.     

Low temperature preparation and uses of potent oxidizers

Because electronegativity of an oxidation state is low in an anion, salts of the high oxidation-state species [AgF₄]⁻ and [NiF₆]²⁻ can be easily made, at 0 °C, in liquid anhydrous HF (aHF) made basic with alkali fluorides. The containers are transparent fluorocarbon, and the F₂ is photo-dissociated. The [NiF₆]²⁻ salts, and the metastable binary fluorides NiF₄ and NiF₃, derived from them, are efficient fluorinating agents for the conversion of hydrido compounds to their fully fluorinated relatives. With F₂ in aHF made acidic with fluoride-ion acceptors (e.g. MF₅, M = As, Sb, Bi) attained oxidation-states are often lower (e.g. Ag^II, Au^II) because of the higher electronegativity in cations. Cationic Ag^III and Ni^IV species (derived from the anions) are sufficiently long-lived, and potent, to generate the most powerfully oxidizing hexafluorides of the second and third transition series (i.e. [MF₆], M = Pt, Ru, Rh). This synthesis is especially valuable for RhF₆, and has provided for the reinvestigation of the interaction of it with O₂. It is proposed that the unexpectedly large unit cell of O₂RhF₆ is a result of the presence of neutral O₂ and neutral RhF₆ as well as O₂⁺ and RhF₆⁻ in the lattice.