An Aqua‐Bridged Helical‐Chain Copper(II)‐Saccharinato Polymer Linked into a Two‐Dimensional Supramolecular Framework

A new assembly [Cu₂(sac)₂(μ‐dmea)₂(μ‐H₂O)]_n (sac = saccharinate and Hdmea = 2‐dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of dinuclear modules of [Cu₂(sac)₂(dmea)₂]. The sac ligand is N‐coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra‐dimer Cu···Cu separation of 3.0229(7) Å. The dimeric units are bridged by aqua ligands to generate a one‐dimensional water‐bridged helical chain, in which the copper(II) ions exhibit a distorted square‐pyramidal CuN₂O₃ coordination. The Cu–Cu distance in the chain separated by the bridging aqua ligands is 5.297Å. The polymeric chains are further linked by π(sac)···π(sac) and C–H···π(sac) interactions into a two‐dimensional supramolecular network.     

Square wave adsorptive stripping voltammetric determination of famotidine in urine

Electrochemical studies of famotidine were carried out using voltammetric techniques: cyclic voltammetry, linear sweep and square wave adsorptive stripping voltammetry. The dependence of the current on pH, buffer concentration, nature of the buffer, and scan rate was investigated. The best results for the determination of famotidine were obtained in MOPS buffer solution at pH 6.7. This electroanalytical procedure enabled to determine famotidine in the concentration range 1 × 10⁻⁹–4 × 10⁻⁸ mol L⁻¹ by linear sweep adsorptive stripping voltammetry (LS AdSV) and 5 × 10⁻¹⁰–6 × 10⁻⁸ mol L⁻¹ by square wave adsorptive stripping voltammetry (SW AdSV). Repeatability, precision and accuracy of the developed methods were checked. The detection and quantification limits were found to be 1.8 × 10⁻¹⁰ and 6.2 × 10⁻¹⁰ mol L⁻¹ for LS AdSV and 4.9 × 10⁻¹¹ and 1.6 × 10⁻¹⁰ mol L⁻¹ for SW AdSV, respectively. The method was applied for the determination of famotidine in urine.     

[Hg2(μ‐bpe)(μ‐OAc)2(μ‐SCN)2]n,a New Two‐Dimensional Coordination Polymer Involving Three Simultaneously Bridging Ligands: 1,2‐Bis(4‐pyridyle)ethene,Acetate, and Thiocyanate

A new mercury(II) complex of 1,2‐bis(4‐pyridyle)ethene (bpe) with anionic acetate and thiocyanate ligands has been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X‐ray analysis shows that the complex is a two‐dimensional polymer with simultaneously bridging 1,2‐bis(4‐pyridyle)ethane, acetate and thiocyanate ligands and basic repeating dimeric [Hg₂(μ‐bpe)(μ‐OAc)₂(μ‐SCN)₂] units. The two‐dimensional system forms a three‐dimensional network by packing via π‐π stacking interactions.     

Thermal decompositions of some divalent transition metal complexes of triethanolamine

The thermal behaviours of the Ti(II), Mn(II), Fe(II), Ni(II), Cu(II) and Zn(II) complexes of triethanolamine were studied by means of thermogravimetry, differential thermogravimetry, differential thermal analysis infrared spectrophotometry and elemental analysis. The sequence of thermal stability of the metal complexes, determined by using the initial decomposition temperature, was found to be Ti(II)?Mn(II)>Fe(II)>Ni(II)>Zn(II)>Cu(II). Some of the kinetic parameters, such as the activation energy and order of reaction for the initial decomposition reaction, were calculated and the relationship between the thermal stability and the chemical structure of the complexes is discussed.     

Synthesis,spectral, thermal and structural characterization of {[Cu(H2O)3][Cu(MAL)2] · 2H2O}∞ and [Cu(MAL)(TEA)] · H2O (MAL = malonate and TEA = triethanolamine)

A polymeric malonato-bridged copper(II) complex, {[Cu(H₂O)₃][Cu(MAL)₂]· 2H₂O}, and a mononuclear malonato-copper(II) complex with triethanolamine, [Cu(MAL)(TEA)]·H₂O, have been prepared and characterized by elemental analyses, i.r., u.v.–vis, magnetic measurements and single crystal X-ray diffraction. The polymeric complex consists of one-dimensional chains containing the MAL bridged [Cu(H₂O)₃]²⁺ and [Cu(MAL)₂]^2– ions and each MAL ligand simultaneously exhibits chelating bidentate (at one copper atom) and bridging (at the adjacent copper atom) coordination modes. The intrachain Cu1...Cu2 separation is 4.963 Å and the polymeric complex exhibits antiferromagnetic behaviour. In the mononuclear complex, the copper(II) ion is octahedrally coordinated by one bidentate MAL and one tetradentate neutral TEA ligands. The i.r. spectra and thermal decompositions of both complexes are described.     

Monoclinic and triclinic concomitant polymorphs of di‐μ‐pyridazine‐1κ2N:2κ2N′‐bis­[(saccharinato)silver(I)]

Crystallization of the title compound, di‐μ‐pyridazine‐1κ²N:2κ²N′‐bis­[(2,3‐dihydro‐3‐oxobenzisosulfonazolato‐κN)silver(I)], [Ag₂(C₇H₄NO₃S)₂(C₄H₄N₂)₂], from acetonitrile yields both monoclinic, (I), and triclinic, (II), polymorphs. In both forms, the silver(I) ions have a slightly distorted trigonal AgN₃ coordination geometry and are doubly bridged by two neutral pyridazine (pydz) ligands, generating a centrosymmetric dimeric structure. The saccharinate (sac) ligands are N‐coordinated. The dihedral angles between the sac and pydz rings are 8.43 (7) and 7.94 (8)° in (I) and (II), respectively, suggesting that the dimeric mol­ecule is nearly flat. The bond geometry is similar in both polymorphs. In (I), the dimers inter­act with each other via aromatic π_sac–π_pydz stacking inter­actions, forming two‐dimensional layers, which are further crosslinked by weak C—H⋯O inter­actions. Compound (II) exhibits similar C—H⋯O and π–π inter­actions, but additional C—H⋯π and π⋯Ag inter­actions help to stabilize the packing of the dimers.     

Raman Spectroscopy Investigation of Nano Hydroxyapatite Doped with Yttrium and Fluoride Ions

In this study, nano hydroxyapatite doped with yttrium (2.5, 5, and 7.5 mol%) and fluoride (2.5 mol%) ions were synthesized by precipitation method and sintered at 900°C, 1100°C, and 1300°C. Raman spectroscopy was applied to track the structural modifications in pure and doped hydroxyapatites. The results showed that the main characteristic band of pure hydroxyapatite at 963 cm^?1 was not affected significantly by ion doping but exhibited higher intensity with increasing sintering temperature. Due to fluoride substitution, the 1048 and 1034 cm^?1 bands of pure hydroxyapatites appeared with a wavenumber shift in the spectra of ion-doped hydroxyapatites. The 333 cm^?1 band of pure hydroxyapatite disappeared and an additional calcium–fluor bond at 322 cm^?1 was observable in ion-doped hydroxyapatites. Two fluorescence bands at 770 and 697 cm^?1, which were also observed in the spectra of pure hydroxyapatites, shifted to higher wavenumbers in the spectra of ion-doped hydroxyapatites. This was considered to result from the perturbation in the hexagonal structure of hydroxyapatite due to yttrium and fluoride codoping.     

Nanocomposites based on crosslinked polyacrylic latex/silver nanoparticles for waterborne high‐performance antibacterial coatings

Functional polymer/AgNPs nanocomposites have been prepared. Silver nanoparticles (NPs) were synthesized to which polyacrylamide, PAAm, was covalently bound. PAAm was synthesized via a RAFT reaction and carried thiol and carboxylic acid end groups. Thiol was used to bind the polymer to the metal surface and carboxyl for further reactions. The AgNPs were used in a post‐crosslinking reaction with a separately synthesized poly(butyl acrylate‐co‐methyl methacrylate)/polyglycidyl methacrylate core/shell latex bearing epoxy functional groups. Dynamic mechanical analysis showed that the functional AgNPs effectively crosslinked the latex polymer, and that the final product had excellent mechanical strength. Antibacterial tests revealed that the nanocomposite films had strong antibacterial activity against all types of the bacteria and the immobilization of silver NPs by crosslinking retarded the release of silver in comparison to the uncrosslinked ones. With the presented method, it is possible to obtain ductile antibacterial nanocomposites to be used as waterborne functional coatings. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1435–1447     

Synthesis of Chiral Calix[4]arene Derivative and Evaluation of its Recognition Properties

The article describes the synthesis and extraction properties of a new chiral calix[4]arene Schiff base ligand 5, which has been synthesized from 5,17-diformyl-25,27-bis-(4-nitrobenzyloxy)-26,28-dihidroxycalix[4]arene (4) by treatment with (S)-(-)-1-phenylethylamine. In this synthesis, it was thought to explore the role of chiral, as well as Schiff base sites in the recognition of targeted species ions (such as dichromate anions) as well as neutral/chiral molecules. At low pH, the ligand 5 is more effective for transferring the dichromate anions from an aqueous into a dichloromethane layer; may be due to the protonation of nitrogen atoms.

The extraction properties of ligand 5 towards the some selected α -amino acid methylesters are also reported. However, the ligand 5 did not display any selectivity towards the selected α-amino acid methylesters.     

Comparison of NMR Water Proton T1 Measurements in Healthy and Pathological Blood

water proton T1 in blood from healthy volunteers and patients with acute leukaemia, lymphoma; iron deficiency anaemia, post hepatitic cirrhosis and tuberculosis, was measured by a FT-NMR spectrometer. Relaxation measurements were performed at 60MHz frequency and a temperature of (20 ± 0.5)C. The T1 measured for each disease correlates strongly with hemoglobin content. The spin-lattice relaxation time in each abnormal group was signaficantly (p < 0.001) elevated over normal group. There is little overlap between the healthy and abnormal groups. On the contrast, T1 ranges obtained for malignant groups and non-malignant diseases do overlap.