Evaluation of carbonic anhydrase and paraoxonase inhibition activities and molecular docking studies of highly water-soluble sulfonated phthalocyanines

The investigation of carbonic anhydrase and paraoxonase enzyme inhibition properties of water-soluble zinc and gallium phthalocyanine complexes ( 1 and 2 ) are reported for the first time. The binding of p-sulfonylphenoxy moieties to the phthalocyanine structure favors excellent solubilities in water, as well as providing an inhibition effect on carbonic anhydrase (CA) I and II isoenzymes and paraoxonase (PON1) enzyme. According to biological activity results, both complexes inhibited hCA I, hCA II, and PON1. Whereas 1 and 2 showed moderate hCA I and hCA II (off-target cytosolic isoforms) inhibitory activity (Ki values of 26.09 µM and 43.11 µM for hCA I and 30.95 µM and 33.19 µM for hCA II, respectively), they exhibited strong PON1 (associated with high-density lipoprotein [HDL]) inhibitory activity (Ki values of 0.37 µM and 0.27 µM, respectively). The inhibition kinetics were analyzed by Lineweaver–Burk double reciprocal plots. It revealed that 1 and 2 were noncompetitive inhibitors against PON1, hCA I, and hCA II. These complexes can be more advantageous than other synthetic CA and PON inhibitors due to their water solubility. Docking studies were carried out to examine the interactions between hCA I, hCA II, and PON1 inhibitors and metal complexes at a molecular level and to predict binding energies.     

Highly improved electrocatalytic oxidation of dimethylamine borane on silver nanoparticles modified polymer composite electrode

Dimethylamine borane (DMAB) is a promising fuel alternative for fuel cell applications. In this work cyclic voltammetric behavior of DMAB was investigated on the polymerized aminophenol film decorated with Ag nanoparticles in alkaline media. The polymer film was formed on the glassy carbon electrode by electrochemical technique and then, the surface was modified with Ag nanoparticles. The surface of the modified electrode was identified by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy techniques. The developed electrode has displayed high electrocatalytic activity for DMAB oxidation in alkaline media depending on the supporting electrolyte concentration. Experimental parameters such as cycle number used in electropolymerization of p-aminophenol, deposition of Ag nanoparticles and supporting electrolyte were optimized.     

The cavities in a random close-packed structure

The cavities in the random close packing of spheres are re-examined with a view to considering the possible applicability of the structure as a model for the arrangement of oxygen atoms in a silicate melt. For this purpose a limit of 1.20 diameters is used to define near contacts between spheres, and this leads to substantial changes in both the numbers and the types of polyhedral cavities found. Serious limitations are deduced for the Si: O ratios of silicate structures for which the random close packing might serve directly as a model, but suggestions are made as to how the introduction of ionic charges might itself tend to modify the packing into a more appropriate form.     

Ein neuer Apparat zur volumetrischen Kohlenstoffbestimmung

Ohne Zusammenfassung     

Quantum cascade laser-based free space optical communications

The advent of the quantum cascade laser (QCL) with emission wavelengths available in the infrared range from 3 μm through more than 100 μm opens up the possibility of exploiting infrared atmospheric transparency windows for free space optical communications. In an effort to establish the efficacy of using directly modulated QCLs for free space communications we have conducted a series of investigations that demonstrate the potential advantages of this technology. In these experiments we first establish that the QCL has very high modulation bandwidth. We then implement a practical free space communications link that under conditions of atmospheric fog, dust and other obscurants offers significant transparency advantage when compared with near infrared wavelength sources presently used in commercial free space optical communications links.     

The NMR spectra and conformations of cyclic compounds: IX—conformational studies of bicyclo(3,1,0)hexane derivatives by 13C NMR

The ¹³C spectra of α-thujene ( 1 ), isothujone ( 2 ), (?)isothujol ( 3 ), (+)neoisothujol ( 4 ), sabinol ( 5 ), dihydroumbellulone ( 6 ) and umbellulone ( 7 ) and the alcohol acetates are recorded and assigned. The C-6 chemical shift may be used in conjunction with the steric shift mechanism as a conformational probe in these molecules. The results obtained indicate that isothujol, neoisothujol, isothujone and dihydroumbellulone adopt boat-like conformations whilst sabinol has a much flatter conformation. Conjugation of the isolated double bond of α-thujene and the carbonyl group of dihydroumbellulone with the cyclopropane ring has virtually no effect on the ¹³C shifts, but those of umbellulone itself are anomalous, indicating conjugation of the α,β unsaturated ketone system with the cyclopropyl ring.     

Asymmetric lithiation-substitution of amines involving rearrangement of borates

Asymmetric lithiation of substituted benzylamines, N-Boc-pyrrolidine, or N-Boc-indoline using Beak's methodology was followed by electrophilic quench with trialkylboranes. The resulting borate intermediates rearrange with concomitant C-N bond breakage to give, after oxidation, chiral secondary alcohols with high enantioselectivity.     

Post-functionalization of ATRP polymers using both thiol/ene and thiol/disulfide exchange chemistry

In this communication, we report on a new route to the functionalization of ATRP polymers exploiting their halide end-groups, which were converted successfully into reactive disulfide end-groups, using sodium methanethiosulfonate. The resultant disulfide-terminated polymers could then be reacted with different functional thiols to yield functional polymers exploiting either thiol/disulfide exchange chemistry or thiol/ene "click" reactions.     

Synthesis of hindered anilines: copper-catalyzed electrophilic amination of aryl boronic esters

No longer a hindrance: copper-catalyzed electrophilic amination of aryl boronic esters is accomplished under mild reaction conditions using 2.5-5.0 mol % of a catalyst derived from copper tert-butoxide and Xantphos ligand. The reaction tolerates a wide range of functional groups and can be used to prepare some of the most hindered anilines made to date.