Sol-gel synthesis of 2-dimensional TiO2: self-assembly of Ti-oxoalkoxy-acetate complexes by carboxylate ligand directed condensation.

2-Dimensional (2D) metal oxides have many potential industrial applications including heterogeneous catalysis, water splitting, renewable energy conversion, supercapacitor applications, biomaterials, gas separation and gas storage. Herein we report a simple and scalable method for the preparation of 2D TiO2 nanostructures by reaction of titanium isopropoxide with acetic acid at 333 K in isopropanol, followed by calcination at 673 K to remove the organic ligands. Both the products and reaction intermediates have been studied using electron microscopy, X-ray diffraction, N2 physisorption, nuclear magnetic resonance, thermogravimetric analysis, and X-ray photoelectron, Raman, and infrared spectroscopy. The anisotropic condensation of the planar Ti6O4(OiPr)8(OAc)8 complex is believed to be responsible for the formation of the 2D structure, where OiPr and OAc represent isopropoxide and acetate ligands, respectively. This research demonstrates that the metal complexes are promising building blocks for desired architectures, and the self-assembly of an acetate bidentate ligand is a versatile tool for manipulating the shape of final products.

Diversification of edaravone via palladium-catalyzed hydrazine cross-coupling: Applications against protein misfolding and oligomerization of beta-amyloid.

N-Aryl derivatives of edaravone were identified as potentially effective small molecule inhibitors of tau and beta-amyloid aggregation in the context of developing disease-modifying therapeutics for Alzheimer's disease (AD). Palladium-catalyzed hydrazine monoarylation protocols were then employed as an expedient means of preparing a focused library of 21 edaravone derivatives featuring varied N-aryl substitution, thereby enabling structure-activity relationship (SAR) studies. On the basis of data obtained from two functional biochemical assays examining the effect of edaravone derivatives on both fibril and oligomer formation, it was determined that derivatives featuring an N-biaryl motif were four-fold more potent than edaravone.

BippyPhos: a single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides.

Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/[Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl]2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho-alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.

Efficient palladium-catalyzed synthesis of substituted indoles employing a new (silanyloxyphenyl)phosphine ligand.

The new and easily prepared OTips-DalPhos ligand (L1) offers broad substrate scope at relatively low loadings in the palladium-catalyzed C-N cross-coupling/cyclization of o-alkynylhalo(hetero)arenes with primary amines, affording indoles and related heterocyclic derivatives in high yield.

Purification of peroxidase from Horseradish (Armoracia rusticana) roots.

Peroxidase (EC 1.11.1.7) from horseradish ( Armoracia rusticana ) roots was purified using a simple, rapid, three-step procedure: ultrasonication, ammonium sulfate salt precipitation, and hydrophobic interaction chromatography on phenyl Sepharose CL-4B. The preparation gave an overall yield of 71%, 291-fold purification, and a high specific activity of 772 U mg(-1) protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified enzyme was homogeneous and had a molecular weight of approximately 40 kDa. The isolated enzyme had an isoelectric point of 8.8 and a Reinheitszahl value of 3.39 and was stable when stored in the presence of glycerol at -20 degrees C, with >95% retention of original enzyme activity for at least 6 months. Maximal activity of purified horseradish peroxidase (HRP) was obtained under different optimized conditions: substrate (guaiacol and H(2)O(2)) concentrations (0.5 and 0.3 mM, respectively), type of buffer (50 mM phosphate buffer), pH (7.0), time (1.0 min), and temperature of incubation (30 degrees C). In addition, the effect of HRP and H(2)O(2) in a neutral-buffered aqueous solution for the oxidation of phenol and 2-chlorophenol substrates was also studied. Different conditions including concentrations of phenol/2-chlorophenol, H(2)O(2), and enzyme, time, pH, and temperature were standardized for the maximal activity of HRP with these substrates; under these optimal conditions 89.6 and 91.4% oxidations of phenol and 2-chlorophenol were obtained, respectively. The data generated from this work could have direct implications in studies on the commercial production of this biotechnologically important enzyme and its stability in different media.