Manganese(III) acetate promoted acetoxylation of various α,β-unsaturated cyclopentanones

We describe the results of manganese(III) acetate based regioselective oxidation of various α,β-unsaturated cyclopentanones leading to α′-acetoxy α,β-unsaturated cyclopentanones in good yields. Products due to monophenyl and diphenyl substituted dimerization have been identified as byproducts of the reaction.     

Synthesis,antimicrobial and antiproliferative activities of new self-assembly benzimidazole-bridged aren ruthenium rectangles in human breast cancer cells

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Some novel benzimidazole-bridged aren ruthenium rectangle compounds of the general structure...     

Study of uranium sorption and desorption on some Turkish clays

The sorption and desorption of uranium on two different clay samples which are obtained from the deposit located in Turgutlu and Kula have been studied by application of a batch technique. The two types of clay materials are Ca-montmorillonite. The uranium concentration range was between 200–3000 ppm. Experimental procedures are outlined and results for uranium contacted with montmorillonite are reported and discussed. The sorption/desorption isotherms were reversible and non-linear for this concentration range. The relative importance of test parameters e.g., pH, clay particle size, temperature, ground water composition, contact — time, solid/water ratio which require definition in order to arrive at meaningful distribution coefficients were carried out. The sorption coefficients varied between 0.65–1.45 and 0.45–1.14 for Kula clay and for Turgutlu clay, respectively. The data could be fitted to Freundlich and Langmuir isotherms. The quantity of the sorbed and desorbed uranium ions was much lower than its theoretical CEC's. This was attributed to a blocking of montmorillonite's CEC by uranium islands sorbed in interlayer. The results have shown that the test parameters can have a marked effect on sorption and the present work provides further evidence of the need to take account of the presence of such materials in safety assessment modeling.     

Halogen-Bonded BODIPY Frameworks with Tunable Optical Features**

The ability to tune the optical features of BODIPY materials in the solid state is essential for their photorelated application and requires efficient control of the crystal packing. In this study, such control of BODIPY supramolecular assemblies was achieved by deliberate design and synthesis of a BODIPY containing a strong halogen-bond (XB) acceptor (−NO₂) and donor (I, Br) to mediate XB interactions. The di-halogenated structures formed isostructural mono-coordinate motif B3 , B4 (1D tubular structure) and symmetric bifurcated motif B4-II (1D zigzag chains structure) through N−O⋅⋅⋅I, Br XB interactions. These XB interactions promote singlet-to-triplet intersystem crossing and triplet-to-singlet reverse intersystem crossing due to partial delocalization of oxygen electrons onto Br and I, which leads to unexpected fluorescence enhancement of B4-II . Finally, the indirect optical band gaps of B3 , B4 and B4-II were amenable to tuning in the range of 1.85–2.50 eV by XB-driven crystal packings.     

Poly[N-(2-hydroxypropyl)methacrylamide]—II: Hydrodynamic properties of dilute solutions

The results of viscosity and light scattering measurements on fractions of poly[N-(2-hydroxypropyl)methacrylamide] in several solvents were used for the determination of the parameters of the Mark-Houwink equation, characteristic ratio and its temperature coefficient and the parameters of the polymer-solvent interaction. The solutions in water and in aq. NaCl are exothermal, in dimethylformamide approx. athermal, and in ethanol endothermal. The effect of the solvent on the short-range interactions between the polymer chain units was also demonstrated.     

Heterogeneous exchange of precipitates

Summary The heterogeneous exchange of ferric ion between a labelled aqueous ferric chloride solution and some differently prepared ferric (hydr)oxides [(1) a freshly formed “amorphous” ferric (hydr)oxide, (2) ferric oxide obtained by drying the freshly formed precipitate in the air at 165 °C for 4.5 hours, (3) ferric oxide obtained by boiling the freshly formed precipitate in water at 100 °C for 4.5 hours] was investigated at room temperature. The exchange rate decreased in the sequence: (1), (2), (3), that sequence being attributed to the recrystallization of the solid phase in the sense of lattice ordering and particle growth, related to the treatment of freshly formed precipitate before the solid was put in contact with the ferric chloride and labelled. System (1) corresponded to a positively charged precipitate near the equivalency of the system FeCl₃ + NaOH, and the exchange was governed by a rapid recrystallization (particle growth), initiated by labelling⁵⁹FeCl₃ solution in an acid (HCl) medium. In the system (2) selfdiffusion is indicated as the exchange governing process. The radionuclide⁵⁴Mn, being present without isotopic carrier in labelling⁵⁹FeCl³ solution and introduced into the liquid phase, remained in the liquid phase of systems (2) and (3). Contribution number 112 from the Department of Physical Chemistry, Faculty of Sciences, University of Zagreb.     

High-performance liquid chromatographic separation of BisGMA oligomers and isomers in dental restorative materials

Summary The composition of the dental monomer BisGMA was analyzed using various techniques of high-performance liquid chromatography (HPLC): isocratic and gradient-elution, normal-phase and reversed-phase-HPLC. These techniques emphasized that BisGMA is not a single compound corresponding to the well known structure of 2,2-Bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane and allowed the separation of BisGMA oligomers and isomers in dental restorative materials. The analysis of the dental resins emphasized the presence of three isomers for each BisGMA oligomer.     

Essential oil composition, antimicrobial and cytotoxic activities of two endemic Stachys cretica subspecies (Lamiaceae) from Turkey

The chemical compositions of the water-distilled essential oil of Stachys cretica ssp. lesbiaca Rech. fil. and S. cretica ssp. trapezuntica Rech. fil. were determined by GC and GC-MS. Altogether 63 compounds were identified. The sesquiterpene hydrocarbon, germacrene D (20.3% and 12.9% respectively) was the main component identified in both oils. Furthermore, ethanol, light petroleum, dichloromethane, ethyl acetate and n-butanol extracts prepared from the aerial parts of the plants were tested for their antimicrobial activities against six bacterial strains and the yeast Candida albicans. The extracts exhibited no antibacterial activity, but the light petroleum and n-butanolic fractions showed low antifungal activities. Crude ethanolic extracts of the two subspecies were tested for their ability to inhibit the growth of HL-60 and Ishikawa human tumor cell lines. The IC50 values were 100 microg/mL for the HL-60 cell line and 200 microg/mL for the Ishikawa cell line.     

Complexation of metal ions with double-armed diazadithia lariat ether carrying anthracene moieties in acetonitrile–dioxane

A new 14-membered crown ether with nitrogen–sulfur donor atom carrying two anthryl groups was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-(chloromethyl) anthracene. The influence of metal cations such as Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ on the spectroscopic properties of the ligand was investigated in acetonitrile–dioxane solution (1/1) by means of absorption and emission spectrometry. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe²⁺, Fe³⁺, Al³⁺, Cd²⁺, Cu²⁺, Zn²⁺, Pb²⁺ and Hg²⁺ cations. Absorption spectra show isobestic points in the spectrophotometric titration of these cations. The presence of excess of Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ cations caused an enhancement of anthryl fluorescence. Especially, the enhancement in case of the interaction of Hg²⁺ and Al³⁺ cations with the ligand was pronounced.     

Synthesis,antioxidant, and anticholinesterase activities of novel N-arylsulfonyl hydrazones bearing sulfonate ester scaffold

In this research, two new series of N-arylsulfonyl hydrazone compounds ( 14 – 25 ) possessing a sulfonate moiety were synthesized and characterized by elemental analysis and various spectroscopic techniques including fourier transform infrared (FT-IR), ¹H-, and ¹³C nuclear magnetic resonance (NMR). These compounds synthesized as target molecules ( 14 – 25 ) were tested for their in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition activities and antioxidant potential. The antioxidant capacities of the tested molecules were determined by four different assays. The IC₅₀ values of the screened molecules were determined in the range of 60.14 ± 0.25–84.81 ± 1.09 μM against AChE and in the range of 70.11 ± 0.67–93.60 ± 0.47 μM against BChE. In the AChE assay, 4-hydroxybenzaldehyde-based compound 25 (60.14 ± 0.25 μM) showed the highest activity in comparison to rivastigmine (501 ± 3.08 μM). This compound (71.42 ± 0.19 μM) is also one of the compounds with the highest activity against BChE. In the BChE assay, 2-hydroxybenzaldehyde-based compound 19 (70.11 ± 0.67 μM) indicated the highest activity in comparison to rivastigmine (19.95 ± 0.20 μM). In antioxidant activity studies, the tested molecules showed lower activities than the standard compounds (butylated hydroxytoluene and α-tocopherol). Consequently, some novel compounds can be used as potential inhibitor candidates in future studies.