Ultrasonic-assisted synthesis and structural characterization of two new nano-structured Hg(II) coordination polymers

Two new Hg(II) coordination polymers containing N,N′-Bis-pyridin-3-ylmethylene-naphtalene-1,5-diamine ligand were synthesized by conventional and sonochemical methods, characterized by spectroscopic techniques (FT-IR and elemental analysis), and their X-ray crystallographic structures were determined. The crystal packing and supramolecular features of these coordination polymers were studied using geometrical analysis and Hirshfeld surface analysis. The crystal structure analysis revealed that H⋯H contacts, C–H⋯π and C–H⋯X (X = Cl for 1 and X = Br for 2) hydrogen bonding interactions are strong enough to govern the supramolecular architecture. The BFDH analysis helps us to compare the predicted morphology to that obtained under ultrasonication. This study may provide further insight into discovering the role of weak intermolecular interactions in the context of nano-supramolecular assembly.     

Hg(II) Coordination Studies in Penicillamine Enantiomers by 199mHg-TDPAC

In order to study the binding of the toxic heavy metal ion Hg²⁺ to penicillamine, complexes with the D- and L-enantiomers of penicillamine were investigated by the nuclear quadrupole interaction of ¹⁹⁹Hg monitored by time differential perturbed angular correlation spectroscopy. It was found that bound Hg(II) occurs in two-fold, three-fold and four-fold coordinations. This revised version was published online in September 2006 with corrections to the Cover Date.     

Functionalized SBA-15 organosilicas as sorbents of zinc(II) ions

SBA-15 nanoporous silicas functionalized with amine-, thiol-, vinyl-, phenyl- and cyano surface groups were synthesized by using the amphiphilic block copolymer P123 as the structure-directing agent. The obtained materials have a well-developed porous structure - the values of specific surface area are in the range 800-950 m²/g and the sizes of cylindrical mesopores are in the range 7.4-8.6 nm. It was established that the size of the mesopores strongly depends even on small amounts of co-monomers co-condensing with TEOS. Adsorption of Zn(II) ions at the SBA-15/NaCl interface was investigated by means of the radioactive isotope tracer technique over the pH range of 3-11. Surface charge density, adsorption density, pH_50% and ΔpH_10-90% parameters for different concentrations of the carrying electrolyte were evaluated and discussed.     

Kinetics and thermodynamics of Pb(II) adsorption onto modified spent grain from aqueous solutions

Spent grain, a main by-product of the brewing industry, is available in large quantities, but its main application has been limited to animal feeding. Nevertheless, in this study, spent grain modified with 1 M NaCl solution as a novel adsorbent has been used for the adsorption of Pb(II) in aqueous solutions. Isotherms, kinetics and thermodynamics of Pb(II) adsorption onto modified spent grain were studied. The equilibrium data were well fitted with Langmuir, Freundlich and Dubinin-Radushkevick (D-R) isotherm models. The kinetics of Pb(II) adsorption followed pseudo-second-order model, using the rate constants of pseudo-second-order model, the activation energy (E_a) of Pb(II) adsorption was determined as 12.33 kJ mol⁻¹ according to the Arrhenius equation. Various thermodynamic parameters such as ΔG^ads, ΔH^ads and ΔS^ads were also calculated. Thermodynamic results indicate that Pb(II) adsorption onto modified spent grain is a spontaneous and endothermic process. Therefore, it can be concluded that modified spent grain as a new effective adsorbent has potential for Pb(II) removal from aqueous solutions.     

Synthesis of a new Hg(II) coordination polymer: Ultrasonic-assisted synthesis and mechanical preparation of nanostructure

A new mercury(II) coordination polymer, [Hg(4-bpmo)I₂]_n (1), (4-bpmo = N,N′-bis(pyridin-4-ylmethyl)oxalamide), was synthesized, by branched tube method, and structurally characterized by single-crystal X-ray diffraction. Compound 1 is a polymer with a distorted tetrahedral HgN₂I₂ coordination environment. The thermal stability of 1 was studied by thermal gravimetric (TG) and differential thermal (DTA) analyses. Also 1 was prepared by a sonochemical process at ambient temperature. Reaction time and concentration of initial reagents effects on the size and morphology were studied. Nanoparticles of 1, was synthesized easily by a mechanical method (neat grinding). The resulting structures were characterized by scanning electron microscopy (SEM), IR spectroscopy and X-ray powder diffraction (XRD).     

Catalytic activity of copper (II) oxide prepared via ultrasound assisted Fenton-like reaction

Copper (II) oxide nanoparticles were synthesized in an ultrasound assisted Fenton-like aqueous reaction between copper (II) cations and hydrogen peroxide. The reactions were initiated with the degradation of hydrogen peroxide by ultrasound induced cavitations at 0 °C or 5 °C and subsequent generation of the OH radical. The radical was converted into hydroxide anion in Fenton-like reactions and copper hydroxides were readily converted to oxides without the need of post annealing or aging of the samples. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) surface area analysis. Catalytic activity of the nanoparticles for the hydrogen peroxide assisted degradation of polycyclic aromatic hydrocarbons in the dark was tested by UV–visible spectroscopy with methylene blue as the model compound. The rate of the reaction was first order, however the rate constants changed after the initial hour. Initial rate constants as high as 0.030 min⁻¹ were associated with the high values of surface area, i.e. 70 m²/g. Annealing of the products at 150 °C under vacuum resulted in the decrease of the catalytic activity, underlying the significance of the cavitation induced surface defects in the catalytic process.     

Chemical optimisation of a sol-gel procedure for the development of fluorescence Cu(II) nanosensors

A template-assisted sol-gel procedure was developed and optimised for the preparation of silica thin films embedding the fluorescent dye 3-(dansylamido)-propyl-triethoxysilane (DNS-APTES) for Cu(II) sensing purposes. The different parameters involved (solution composition, nature of the template, deposition and annealing conditions, post-synthesis deposition of additional coatings, etc.) were independently changed in order to evaluate their effect on the final microstructure, composition and sensor performances of the films. The optimisation procedure encompassed also the choice of the suitable parameters to ensure stability of the sensing films and to avoid the leaching of the fluorescent dye.Films prepared by using the non-ionic surfactant F127, without an additional coating and with a post-deposition annealing at 100 °C for 2 h, were proven to be the best performing ones, characterised by the largest and fastest fluorescence quenching. In particular, the presence of a template was demonstrated to play a major role in determining the efficiency of the sensing device. The surface and in-depth composition of thin films was analysed by X-Ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS). The sensing performances of the films were tested by titration experiments with Cu²⁺.     

Surface modification of hydroxyapatite with poly(methyl methacrylate) via surface-initiated ATRP

This article describes the fabrication of hydroxyapatite (HAP) nanocomposites grafted with poly(methyl methacrylate) (PMMA). Surface-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was carried out from hydroxyapatite particles derivatized with ATRP initiators. The structure and properties of the nanocomposites were investigated by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), differential scanning calorimeter (DSC) measurements, and contact angle analyses. TGA was used to estimate the grafting density of ATRP initiators (0.49 initiator/nm²) and the amount of grafted PMMA on the HAP surface. The contact angle analyses indicated that grafting PMMA onto the HAP surface dramatically increased the hydrophobicity of the surface. Moreover, the HAP nanocomposites showed excellent dispersibility in both aqueous solution and organic solvent.     

硫在Fe(100)面吸附的第一性原理研究

基于密度泛函理论的第一性原理方法,在广义梯度近似下,计算了硫原子在Fe(100)面吸附的结构和电子性质,并计算了其分子轨道和吸附能.同时讨论了相关吸附性质与硫原子表面覆盖度(0.25-1.0ML)的关系.结果表明：硫原子吸附在H位最稳定,吸附能均随浓度的增加而单调增加;B位吸附的硫原子与Fe(100)表面的距离随浓度非单调变化,在0.5ML时达到最大,是由较高的局域电子云重叠产生的排斥作用所导致的;对比分析吸附前后硫和Fe的s及p电子的态密度,显示了硫化亚铁的生成.     

Magnetic properties of 1d systems with a subtle stacking of copper(II) ions

In the last two decades, many studies have been reported on infinite Id networks of magnetically interacting metal ions. Until now, closed-form expressions for the partition function and related properties were mainly derived for the S = f Ising chain model (Ising, 1925), the XY model (Kastura, 1962) or for the classical limit S –t co with arbitrary spin dimensionality (Fischer, 1964). Recently, experimental and theoretical studies have focused on new Id systems made of alternating spin and/or Lande factors (Georges, Curely and Drillon, 1985; Drillon et al., 1983). This has motivated our interest in the behavior of new systems of copper(II) ions in which the magnetic sites form an exotic stacking in one direction of the crystal. Then, the specific behavior is related to the competition between different interactions, as occurs in the systems reported here, namely A₃Cu₃(PO₄)₄, with A = Ca, Sr, Cu₃(PO₄)₂ and Cu₂O(SO₄).     

IR-Spectral Study of 2-Aminopyridine and Aniline Complexes with Palladium (II)

An IR-spectral study of sulphato- and chloro complexes of palladium (II) with 2-aminopyridine and aniline, respectively, is reported. The results obtained confirm the bidentate co-ordination of both 2-aminopyridine and SO₄ group in the case of sulphato-2-aminopyridine-palladium (II) leading to polynuclear structure of the complex in solution. The comparative investigation of sulphato-dianiline-palladium (II) suggests that the self-dependent ability of the SO₄ ^2- ion for bridging co-ordination can stabilize chain-like complexes of palladium (II) only in the solid state.     

CH_4、H_2O在CaCO_3(010)表面吸附的第一性原理研究

基于密度泛函理论第一性原理方法,研究了CH_4和H_2O在CaCO_3(010)面上各高对称位的吸附情况,优化了CH_4与H_2O在T位、 B位和H位的吸附模型结构,计算了其在各高对称位的吸附能,并对其各自最稳定的吸附位吸附前后的物理结构和电子态密度进行了对比分析.结果表明:CH_4、 H_2O分子分别在LBⅢ位、 SBⅢ位最稳定,吸附能分别为-0.405 eV、-0.138 eV,是一种物理吸附,吸附前后键长键角的变化较小,表现为亲气;吸附后CH_4和H_2O的态密度曲线整体向低能量区偏移约7.5 eV、 5eV,吸附后CH_4和H_2O结构都更加稳定,吸附作用对CH_4和H_2O分子的电子结构影响显著.     

Aqueous Cobalt(II) ion as a Nitrogen-14 Chemical Shift Reagent and Its Application to the Determination of Betaine,Glycerophosphorylcholine and Ammonium Ion

Aqueous cobalt(II) ion is shown to be an effective chemical shift reagent for nitrogen-14 nuclear magnetic resonance spectroscopy. Addition of an 8 fold excess of cobalt (II) ion to a mixture of betaine, glycerophosphorylcholine and ammonium ion results in baseline resolution of the three components. The chemical shift of each component is a function of cobalt concentration up to a molar ratio of about 4:1 after which, the shifts     

Synthesis and characterization of a new nano lead(II) 0-D coordination supramolecular compound: A precursor to produce pure phase nano-sized lead(II) oxide

Nano-structure of a new 0D Pb(II) coordination supramolecular compound, [Pb₄(8-Quin)₆](ClO₄)₂(1), L = 8-HQuin = 8-hydroxyquinolin ligand has been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) and elemental analyses. The structure of compound 1 was determined by single-crystal X-ray diffraction. The single crystal X-ray data of compound 1 implies that the Pb⁺² ions are five coordinated. Each lead atom is coordinated to nitrogen and oxygen atoms of 8-hydroxyquinolin ligand. Topological analysis shows that the compound 1 is 1,2,3,4,4M12-1net. Nanoparticles of lead(II) oxide have been prepared by calcination of lead(II) coordination polymer at 500 °C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and IR spectroscopy.     

Converting an Almost Noncytotoxic Ru(II) Complex with Photolabile Ligands into a Highly Efficient PACT Agent

Ru(II) complexes with weak ligand fields may undergo light-induced ligand dissociation, and the resulted Ru(II) aqua complexes may bind with biomolecules such as DNA, showing potential as photoactivated chemotherapy (PACT) agents. However, Ru(II) complexes with efficient PACT activity are still rare. Some Ru(II) complexes exhibit efficient photoinduced ligand dissociation but poor cytotoxicity. It is speculated that the low nuclear accumulation levels may account for their low PACT efficacy. In order to confirm this hypothesis, the almost noncytotoxic [Ru(7-OCH₃-dppz)(4-OCH₃-py)₄](PF₆)₂ (Ru1) is loaded on nucleus-targeted C₅N₂ nanoparticles (NPs). Compared with the free Ru1, Ru1–C₅N₂ NPs exhibit significantly increased cellular uptake and nuclear accumulation. Therefore, Ru1–C₅N₂ NPs show efficient PACT activity toward various cancer cell lines (including cisplatin-resistant one) with half maximal inhibitory concentration (IC₅₀) values of 0.18 × 10⁻⁶–0.29 × 10⁻⁶ m and phototoxicity index (IC₅₀^dark/IC₅₀^light) values above 137 under both normoxic and hypoxic conditions. Moreover, Ru1–C₅N₂ NPs also exhibit efficient PACT activity toward cisplatin-resistant 3D multicellular tumor spheroids upon two-photon irradiation (800 nm). The same strategy is also feasible to greatly improve the PACT activity of [Ru(7-OCH₃-dppz)(py)₄]²⁺, which itself only has a medium effect. The results may provide new sights for developing efficient Ru(II) PACT agents.     

Luminescence quenching of [Ru(bpy)3] by ruthenium(II) tetraphosphite complexes with different phosphite ligands

The luminescence quenching of excited Tris(2,2-bipyridine)ruthenium(II) ions by trans-[RuCl₂{P(OR)₃}₄] complexes with different alkyl chain ligands (R=C₂H₅, C₂H₅Cl, ⁿC₄H₉, ⁱC₃H₇ o-tolyl and ^tC₄H₉) was investigated. None of the acceptor Ru(II) phosphite complexes were luminescent, and the rate constants of the bimolecular system were determined within the range of 1.15 and 0.28×10⁸ M⁻¹ s⁻¹ for R=C₂H₅ and ^tC₄H₉, respectively. The results indicate a direct effect of the alkyl chains in the rate constants, showing a decrease of k_q as a function of increased of the alkyl chains (R) in the ruthenium(II) tetraphosphite complexes. The greater the R group content in the phosphite ligand, the more difficult the electron transfer is.     

IR- and UV-Spectral Study on the Mechanism of 2-Aminopyridine Complexation with Palladium (II)

Abstract

The IR-spectra of Pd (II) complexes with 2-aminopyridine, obtained both in sulphuric acid and alkaline solution are studied in the region 1700- 1400 cm^?1. The structural conclusions are based on comparison with the IR- and UV-spectra of the free ligand and aminopyridinium sulphate, as well as of trans-dichloro-di-2-aminopyridine-palladium and deuterated at the amino group analogues of the investigated compounds.     

Sonochemical effect on two new Ruthenium(II) complexes with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline precursors for synthesis of RuO2 nanoparticles

Two novel Ru(II) complexes [(η⁶-p-cymene)RuCl(L2)]PF₆ (R2) and [(η⁶-C₆H₆)RuCl(L2)]PF₆ (R4), with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline (L2), were synthesized and characterized by elemental analysis, ¹H NMR, ¹³C NMR and IR spectroscopy. Based on X-ray crystallography studies, complexes R2 and R4 have coordination environments with formulated (η⁶-p-cymene)Ru(N₂Cl) and (η⁶-C₆H₆)Ru(N₂Cl), respectively. The thermal stabilities of compounds R2 and R4 were studied by thermal gravimetric (TG) and differential scanning calorimetry (DSC). Thermal decomposition of these complexes was at 280 °C and 260 °C under air atmosphere respectively. The interaction of these complexes with calf thymus DNA (CT-DNA) was explored through electronic absorption spectra, fluorescence and redox behavior studies. The results showed that the complexes bind to CT-DNA with electrostatic interactions. Nanoparticles of RuO₂ were prepared by calcination of R2 and R4. Also the role of the ultrasound waves on the characteristics of the RuO₂ nanoparticles was studied. The nanoparticles were characterized by IR spectroscopy and X-ray diffraction (XRD). Also size and morphology of nanoparticles were studied by scanning electron microscopy (SEM).     

Sonochemical synthesis of two new nano structure zinc(II) 1,10-phenanthroline coordination supramolecular compounds: New precursors to produce nano-sized zinc(II) oxide

Nanoparticles of two zinc(II) coordination supramolecule compounds (CSCs), [Zn(L)Cl2] (1) and [Zn(L)Br2] (2) L = 1,10-phen = 1,10-phenanthroline ligand, have been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compounds 1 and 2 imply that the Zn⁺² ions are four coordinated. Topological analysis shows that the compound 1 and 2 are new topology for net: 1,3M4-1. Nanoparticles of zinc(II) oxide have been prepared by calcination of two different zinc(II) CPs at 500 °C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and IR spectroscopy.     

钴络合物催化甲醇羰基化制甲酸甲酯反应的理论研究

本文运用密度泛函理论B3LYP方法,对C、O、H采用6-311+G(2d,p)基组,计算研究了钴络合物催化甲醇羰基化制甲酸甲酯反应的微观机理,优化了各反应物、中间体和过渡态的构型特征,用频率分析方法和内禀反应坐标方法对过渡态进行了验证,同时对各中间体进行电荷分析.对比了催化过程与非催化过程的能垒.结果表明,有催化剂参与后反应活化能明显降低.