Preparation of calix[4]arene-based sporopollenin and examination of its dichromate sorption ability

The present study describes the preparation of a new calix[4]arene-based sporopollenin material and its application for the removal of Na₂Cr₂O₇ from aqueous solution. The novel calix[4]arene-based sporopollenin material was prepared via the immobilization of dihydrazine amide derivative of p-tert-butylcalix[4]arene (3) onto the modified sporopollenin. The newly prepared calix[4]arene-based sporopollenin is characterized by using different analytical techniques such as FT-IR spectroscopy, scanning electron microscope and Elemental analysis. The batch wise sorption study was carried out to optimize various experimental parameters such as the effect of sorbent dosage, pH, temperature and Cr(VI) anion concentration. It has been found that the sorption of Cr(VI) anion on calix[4]arene-based sporopollenin was highly pH dependent and maximum sorption was achieved at pH 1.5. The sorption behavior was also evaluated by Langmuir, Freundlich and Dubinin Radushkevich isotherms. The value of correlation coefficient (R ²) showed a good agreement with Freundlich isotherm model. Result of study demonstrated that calix[4]arene-based sporopollenin proved to be highly effective for the removal of Cr(VI).     

Anticancer activities of manganese-based photoactivatable CO-releasing complexes (PhotoCORMs) with benzimidazole derivative ligands

Carbon monoxide is an important signaling molecule which is produced by heme oxygenase-1. CO shows antiproliferative activity against cancer cells; hence, activation of HO-1 is a significant inhibition strategy against tumor formation and survival of cancer cells. In this work, manganese-based CO-releasing molecules (CORMs) were designed and synthesized to inhibit breast cancer cell proliferation. Human invasive ductal breast cancer cells (MCF-7) were treated with the synthesized CORMs to investigate the effect of the complexes on breast cancer survival under UV light. In vitro experiments indicated that the complexes inhibited breast cancer cell proliferation, and further, the antiproliferative effects were increased under UV light. Thus, these novel CORMs may provide a drug template for the treatment of invasive ductal breast cancer.     

Strong ideal convergence in probabilistic metric spaces

In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this space and investigate some properties of these concepts.     

Bilevel programming for generating discrete representations in multiobjective optimization

Mathematical Programming - The solution to a multiobjective optimization problem consists of the nondominated set that portrays all relevant trade-off information. The ultimate goal is to identify...     

Hydrophobic cryogels for DNA adsorption: Effect of embedding of monosize microbeads into cryogel network on their adsorptive performances

As alternative hydrophobic adsorbent for DNA adsorption, supermacroporous cryogel disks were synthesized via free radical polymerization. In this study, we have prepared two kinds of cryogel disks: (i) poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐l ‐tryptophan) [p(HEMA‐MATrp)] cryogel containing specific hydrophobic ligand MATrp; and (ii) monosize p(HEMA‐MATrp) particles synthesized via suspension polymerization embedded into p(HEMA) cryogel structure to obtain p(HEMA‐MATrp)/p(HEMA) composite cryogel disks. These cryogel disks containing hydrophobic functional group were characterized via swelling studies, Fourier transform infrared spectroscopy, elemental analysis, surface area measurements and scanning electron microscopy. DNA adsorption onto both p(HEMA‐MATrp) cryogel and p(HEMA‐MATrp)/p(HEMA) composite cryogels was investigated. Maximum adsorption of DNA on p(HEMA‐MATrp) cryogel was found to be 15 mg/g polymer. Otherwise, p(HEMA‐MATrp)/p(HEMA) composite cryogels significantly increased the DNA adsorption capacity to 38 mg/g polymer. Composite cryogels could be used repeatedly without significant loss on adsorption capacity after 10 repetitive adsorption–desorption cycles. Copyright © 2013 John Wiley & Sons, Ltd.     

Butylene linked palladium N-heterocyclic carbene complexes: Synthesis and catalytic properties

New bis(NHC)-Pd complexes were synthesized and characterized by elemental analysis, ¹H NMR, ¹³C NMR, and IR spectroscopy. The reaction of Pd(OAc)₂ and bis(benzimidazolium) salts in DMSO gave the monomeric palladium complex in which the N-heterocyclic carbene was bound to the metal centre. The crystal and molecular structure of the cis-dibromo{1,1′-di[2,3,4,5,6-pentamethylbenzyl]-3,3′-butylenedibenzimidazol-2,2′-diylidene}-palladium(II) complex was determined by single-crystal X-ray diffraction. The activity of the Pd(II) complexes in the direct arylation of benzothiazole with arylbromides was investigated. A preliminary catalytic study showed that these bis(NHC)-Pd complexes were highly active in the direct arylation of benzothiazole with arylbromides.     

A novel approach for highly proton conductive electrolyte membranes with improved methanol barrier properties: Layer-by-Layer assembly of salt containing polyelectrolytes

A series of highly proton conductive electrolyte membranes with improved methanol barrier properties are prepared from polyallylamine hydrochloride (PAH) and polystyrene sulfonic acid (PSS) including salt by Layer-by-Layer (LbL) method. The effects of added salt type (NaCl, MgCl₂) and salt concentration (1.0 M, 0.1 M) on proton conductivity (σ) and methanol barrier properties of the LbL self-assembled composite membranes are discussed in terms of controlled layer thickness and charge density. Furthermore, the influences of ion type in the multilayered composite membranes are studied in conjunction with physicochemical and thermal properties.The deposition of the self-assembly of PAH/PSS film on Nafion is followed by UV–Vis spectroscopy and it is observed that the polyelectrolyte layers growth on both sides of Nafion membrane regularly. (PAH/PSS)₅–Na⁺ and (PAH/PSS)₅–H⁺ with 1.0 M NaCl exhibits 49.6 and 27.8% reduction in lower methanol permittivity in comparison with the pristine Nafion^®117, respectively, while the proton conductivities are 12.97 and 74.69 mS cm⁻¹. Promisingly, it is found that the membrane selectivity values (Φ) of all multilayered membranes in H⁺ form are much higher than that of salt form (Na⁺ and Mg²⁺) and perfluorosulfonated ionomers reported in the literature. Also, we find out that the use of polyelectrolytes with high charge density causes a further improvement in proton conductivity and methanol barrier properties simultaneously. These encouraging results indicate that upon a suitable choice of LbL deposition conditions, composite membranes exhibiting both high proton conductivity and improved methanol barrier properties can be tailored for fuel cells.     

Simple high-performance liquid chromatographic method for determination of atropine and obidoxime in a parenteral injection device

Atropine and obidoxime in a parenteral injection device are determined by simple HPLC method simultaneously without any pretreatment at 228 nm. The relative standard deviations (R.S.D.) were below 1.6% for the compounds. The correlation coefficient was greater than 0.999 for both compounds in the calibration range. The recoveries at 5 mg/L concentration averaged as 95% for atropine and 102% for obidoxime. The uncertainty of the measurements for atropine and obidoxime was 2.8% and 2.4%, respectively.     

Eta6-mesityl,eta1-imidazolinylidene-carbene-ruthenium(II) complexes: catalytic activity of their allenylidene derivatives in alkene metathesis and cycloisomerisation reactions

The reaction of electron-rich carbene-precursor olefins containing two imidazolinylidene moieties [(2,4,6-Me(3)C(6)H(2)CH(2))NCH(2)CH(2)N(R)Cdbond;](2) (2a: R=CH(2)CH(2)OMe, 2 b R=CH(2)Mes), bearing at least one 2,4,6-trimethylbenzyl (R=CH(2)Mes) group on the nitrogen atom, with [RuCl(2)(arene)](2) (arene=p-cymene, hexamethylbenzene) selectively leads to two types of complexes. The cleavage of the chloride bridges occurs first to yield the expected (carbene) (arene)ruthenium(II) complex 3. Then a further arene displacement reaction takes place to give the chelated eta(6)-mesityl,eta(1)-carbene-ruthenium complexes 4 and 5. An analogous eta(6)-arene,eta(1)-carbene complex with a benzimidazole frame 6 was isolated from an in situ reaction between [RuCl(2)(p-cymene)](2), the corresponding benzimidazolium salt and cesium carbonate. On heating, the RuCl(2)(imidazolinylidene) (p-cymene) complex 8, with p-methoxybenzyl pendent groups attached to the N atoms, leads to intramolecular p-cymene displacement and to the chelated eta(6)-arene,eta(1)-carbene complex 9. On reaction with AgOTf and the propargylic alcohol HCtbond;CCPh(2)OH, compounds 4-6 were transformed into the corresponding ruthenium allenylidene intermediates (4-->10, 5-->11, 6-->12). The in situ generated intermediates 10-12 were found to be active and selective catalysts for ring-closing metathesis (RCM) or cycloisomerisation reactions depending on the nature of the 1,6-dienes. Two complexes [RuCl(2)[eta(1)-CN(CH(2)C(6)H(2)Me(3)-2,4,6)CH(2)CH(2)N- (CH(2)CH(2)OMe)](C(6)Me(6))] 3 with a monodentate carbene ligand and [RuCl(2)[eta(1)-CN[CH(2)(eta(6)-C(6)H(2)Me(3)-2,4,6)]CH(2)CH(2)N-(CH(2)C(6)H(2)Me(3)-2,4,6)]] 5 with a chelating carbene-arene ligand were characterised by X-ray crystallography.