Thermal and chromatographic behaviour of metal complexes. Part III. Complexes of palladium(II) with iminodiacetic acid

A study of the thermal properties of the complexes formed between Pd(II) and iminodiacetic acid (IDA) and the chromatographic analysis of their thermal decomposition products have been carried out. The dehydration of the isolated compounds is detected above 100°C. The decarboxylation process of the COO^? groups takes place yielding CO₂ and CO simultaneously or consecutively if they are not coordinated, respectively. The formation of gases (methane, ethane, etc.) is also observed.     

Spectrophotometric determination of trace amounts of iron(III) by extraction of the mixed-ligand iron-fluoride-purpurin complex

The characteristics of the mixed-ligand iron(III)-fluoride-purpurin complex, including optimum conditions of formation and extraction into methyl isobutyl ketone are described. A procedure for determination of trace amounts of iron in fluoride medium (0.5M) with purpurin (1,2,4,-trihydroxy-anthraquinone) in methyl isobutyl ketone is given. The method is suitable for determining iron in the presence of large amounts of aluminium, cyanide, phosphate and nickel.     

New progesterone esters as 5alpha-reductase inhibitors

The pharmacological activity of four new progesterone derivatives: 4-bromo-17alpha-(p-fluorobenzoyloxy)-4-pregnene-3,20-dione (7), 4-bromo-17alpha-(p-bromobenzoyloxy)-4-pregnene-3,20-dione (8), 4-bromo-17alpha-(p-chlorobenzoyloxy)-pregnene-3,20-dione (9) and 4-bromo-17alpha-(p-toluoyloxy)-4-pregnene-3,20-dione (10) was determined. These compounds were evaluated as 5alpha-reductase inhibitors on gonadectomized hamster seminal vesicles and flank organs. The pharmacological data of this study indicate that compounds 7 and 9 having at C-17 p-fluorobenzoyloxy and p-chlorobenzoyloxy ester functions respectively showed the highest antiandrogenic effect as measured by the reduction of the weight of the seminal vesicles. In the flank organ model, the same compounds 7 and 9 exhibited a smaller diameter, 1.8 and 1.0 mm, respectively, than the commercially available finasteride 3 (2.3 mm), thus indicating a higher inhibitory effect on 5alpha-reductase enzyme. Steroid 7 showed a higher inhibitory activity on the conversion of T to DHT (Fig. 3) than the presently used finasteride, thus indicating a higher antiandrogenic effect. The nonsubstituted benzoyloxy ester (compound 15) showed a lower antiandrogenic activity as measured in the seminal vesicles model than the p-substituted benzoyloxy compounds.     

Synthesis, primary photophysical and antibacterial properties of naphthyl ester cinoxacin and nalidixic acid derivatives

We have synthesized two naphthyl ester quinolone derivates and determined their ability to generate reactive oxygen species (ROS) such as (1)O(2), ()OH, H(2)O(2) upon photolysis with UV-A light. The ability of cinoxacin (1) and nalidixic acid (2), and their naphthyl ester derivatives (3 and 4) to generate a dose-dependent amount of singlet oxygen and ROS (()(-)O(2), ()OH) in cell-free systems was detected by histidine assay and by luminol-enhanced chemiluminescence (LCL), respectively. Their electronic absorption and emission spectra were quantified and their photostability was determined. Their tendency to generate peroxidic derivative species showed the following order: 3>4; in contrast, their ability to generate singlet oxygen was 4>3 and these were better sensitizers than their parent quinolones 1 and 2. The antibacterial activity in darkness and under irradiation of compounds 3 and 4 was tested on Escherichia coli and compared with that of their parent compounds. An enhanced antibacterial activity by irradiation of the naphthyl esters of cinoxacin and nalidixic acid on E. coli was observed.     

Abraham Model Correlations for Triethylene Glycol Solvent Derived from Infinite Dilution Activity Coefficient,Partition Coefficient and Solubility Data Measured at 298.15 K

A gas chromatographic headspace analysis method was used to experimentally determine gas-to-liquid partition coefficients and infinite dilution activity coefficients for 29 liquid organic solutes dissolved in triethylene glycol at 298.15 K. Solubilities were also determined at 298.15 K for 23 crystalline nonelectrolyte organic compounds in triethylene glycol based on spectroscopic absorbance measurements. The experimental results of the headspace chromatographic and spectroscopic solubility measurements were converted to gas-to-triethylene glycol and water-to-triethylene glycol partition coefficients, and molar solubility ratios using standard thermodynamic relationships. Expressions were derived for solute transfer into triethylene glycol by combining our measured experimental values with published literature data. Mathematical correlations based on the Abraham model describe the observed partition coefficient and solubility data to within 0.16 log₁₀ units (or less).     

Nanoconfinement Inside Molecular Metal Oxide Clusters: Dynamics and Modified Encapsulation Behavior

Encapsulation behavior, as well as the presence of internal catalytically active sites, has been spurring the applications of a 3 nm hollow spherical metal oxide cluster {Mo₁₃₂} as an encapsulation host and a nanoreactor. Due to its well‐defined and tunable cluster structures, and nanoscaled internal void space comparable to the volumes of small molecules, this cluster provides a good model to study the dynamics of materials under nanoconfinement. Neutron scattering studies suggest that bulky internal ligands inside the cluster show slower and limited dynamics compared to their counterparts in the bulk state, revealing the rigid nature of the skeleton of the internal ligands. NMR studies indicate that the rigid internal ligands that partially cover the interfacial pore on the molybdenum oxide shells are able to block some large guest molecules from going inside the capsule cluster, which provides a convincing protocol for size‐selective encapsulation and separation.     

Synthesis and optical characterization of photoactive poly(2‐phenoxyethyl acrylate) copolymers containing azobenzene units,prepared by frontal polymerization using novel ionic liquids as initiators

2‐Phenoxyethyl acrylate (2‐PEA) was polymerized alone and in the presence of an azobenzene comonomer derived from Disperse Red‐1, N‐ethyl‐N‐(2‐hydroxyethyl)‐4‐(4‐nitrophenylazo)aniline (MDR‐1), by using the frontal polymerization technique. Two novel ionic liquids, recently synthesized by us, were used as initiators: tetrabutylphosphonium persulfate (TBPPS) and trihexyltetradecylphosphonium persulfate (TETDPPS). Even if their concentrations were smaller than those found when benzoyl peroxide and terbutylperoxy neodecanoate were used, these compounds gave rise to stable propagating polymerization fronts characterized by relatively low maximum temperatures and good velocities. Moreover, at variance to these latter, TBPPS and TETDPPS prevent bubble formation, thus allowing the use of the obtained materials in optical applications. The obtained polymers were characterized by infrared spectroscopy (FTIR), their thermal properties were determined by differential scanning calorimetry, and their optical properties were studied by absorption spectroscopy in the UV–vis region. Finally, the nonlinear optical (NLO) properties of the 2‐PEA/MDR‐1 copolymers obtained with TBPPS and TETDPPS were performed according to the Z‐Scan technique with prepared film samples. It has been proven that samples with higher MDR‐1 content (0.05 mol %) exhibited outstanding cubic NLO activity with negative NLO refractive coefficients around n₂ = ?1.7 × 10^?3 esu. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012