Bacterial Binding to Polydopamine-Coated Magnetic Nanoparticles.

In medical infections such as blood sepsis and in food quality control, fast and accurate bacteria analysis is required. Using magnetic nanoparticles (MNPs) for bacterial capture and concentration is very promising for rapid analysis. When MNPs are functionalized with the proper surface chemistry, they have the ability to bind to bacteria and aid in the removal and concentration of bacteria from a sample for further analysis.

Cadmium and silver complexes of a pyridine containing ligand: syntheses, structural studies, biological activity and docking studies.

The current study aimed to synthesize seven new metal coordination complexes (Q1-Q7) with potential biomedical applications. Novel mononuclear, polynuclear and mixed-ligand coordination compounds of the elements, cadmium(ii) and silver(i) derived from a pyridine containing ligand (2,4,6-tris-(2-pyridyl)-1,3,5-triazine ()) have been synthesized successfully with the general formulae [Cd()Cl]·HO and [Ag () (L)(ClO)](ClO) ( = 1,2,3, = 1,2,3, L = PPh or phen, = 1,2). The structural features were fully characterized using various spectroscopic techniques, such as infrared, ultraviolet-visible spectroscopy, 1D and 2D-NMR (H, C, P, H-H COSY and H-C HSQCAD), CHN analysis, molar conductance (), thermogravimetric analysis (TGA), and powder X-ray diffraction analysis.

Intramolecular Heteroatom and Styryl Diels-Alder Reactions, Asymmetric Cycloadditions of Chiral 3-Phenylallyl Maleic Esters.

Polycyclic aryl naphthalene and tetralin dihydro arylnaphthalene lactone lignans possess anticancer and antibiotic activity. Related furo[3,4-]pyranones, typified by the sequester-terpenoid isobolivianine, show similar antiproliferative bioactivity. Efficient syntheses of compounds featuring these polycyclic cores have proven challenging due to low yields and poor stereoselectivity.

Data Mining for Terahertz Generation Crystals.

A data mining approach to discover and develop new organic nonlinear optical crystals that produce intense pulses of terahertz radiation is demonstrated. The Cambridge Structural Database is mined for non-centrosymmetric materials and these structural data are used in tandem with density functional theory calculations to predict new materials that efficiently generate terahertz radiation. This enables us to (in a relatively short time) discover, synthesize, and grow large, high-quality crystals of four promising materials and characterize them for intense terahertz generation.

Medium and Large -Heterocycle Formation via Allene Hydroamination with a Bimetallic Rh(II) Catalyst.

We report the synthesis of a 2-phosphinoimidazole-derived bimetallic Rh(II) complex that enables intramolecular allene hydroamination to form 7- to 10-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of various -heterocycles.

Boron-Templated Dimerization of Allylic Alcohols To Form Protected 1,3-Diols via Acid Catalysis.

We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.

Terahertz generation and optical characteristics of P-BI.

We present the structural and THz generation characteristics of the molecular salt crystal (E)-2-(4-(dimethylamino)styryl)-1,1,3-trimethyl-1H-benzo[e]indol-3-ium iodide (P-BI) using optical rectification with IR pump wavelengths. P-BI shows a peak-to-peak field ∼6 times greater than inorganic crystal GaP, and a broader THz spectrum. Data were obtained from 0-6 THz showing a significant dip in generation at 1.

Synthesis and characterization of ethyl benzotriazolyl acrylate-based D-π-A fluorophores for live cell-based imaging applications.

A series of eight new ethyl ()-benzotriazolyl acrylates 6a-d and 7a-d have been synthesized by conventional heating and microwave irradiation from ethyl benzotriazolyl acetates 3 and 4 with the corresponding aromatic aldehydes. This work reports the synthetic approach and spectroscopic characterization (H, C-NMR, HRMS) of all the synthesized compounds. X-ray diffraction analyses were performed for molecules 6a, 7a and 7d.

Synthesis and Computational Studies Demonstrate the Utility of an Intramolecular Styryl Diels-Alder Reaction and Di-t-butylhydroxytoluene Assisted [1,3]-Shift to Construct Anticancer dl-Deoxypodophyllotoxin.

Deoxypodophyllotoxin is a secondary metabolite lignan possessing potent anticancer activity with potential as a precursor for known anticancer drugs, but its use is limited by scarcity from natural sources. We here report the total synthesis of racemic deoxypodophyllotoxin in seven steps using an intramolecular styryl Diels-Alder reaction strategy uniquely suited to assemble the deoxypodophyllotoxin core. Density functional theory was used to analyze concerted, polar, and singlet-open-shell diradical reaction pathways, which identified a low-energy concerted [4 + 2] Diels-Alder pathway followed by a faster di-t-butylhydroxytoluene assisted [1,3]-formal hydrogen shift.

Surface Spectroscopic Signatures of Mechanical Deformation in High-Density Polyethylene (HDPE).

High-density polyethylene (HDPE) has been extensively studied, both as a model for semi-crystalline polymers and because of its own industrial utility. During cold drawing, crystalline regions of HDPE are known to break up and align with the direction of tensile load. Structural changes due to deformation should also manifest at the surface of the polymer, but until now, a detailed molecular understanding of how the surface responds to mechanical deformation has been lacking.

Multi-instrument characterization of five nanodiamond samples: a thorough example of nanomaterial characterization.

Here, we report the most comprehensive characterization of nanodiamonds (NDs) yet undertaken. Five different samples from three different vendors were analyzed by a suite of analytical techniques, including X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), inductively coupled plasma mass spectrometry (ICP-MS), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), Brunauer-Emmett-Teller (BET) surface area measurements, and particle size distribution (PSD) measurements. XPS revealed the elemental compositions of the ND surfaces (83-87 at.

Origin of fast catalysis in allylic amination reactions catalyzed by Pd-Ti heterobimetallic complexes.

Experiments and density functional calculations were used to quantify the impact of the Pd-Ti interaction in the cationic heterobimetallic Cl2Ti(N(t)BuPPh2)2Pd(η(3)-methallyl) catalyst 1 used for allylic aminations. The catalytic significance of the Pd-Ti interaction was evaluated computationally by examining the catalytic cycle for catalyst 1 with a conformation where the Pd-Ti interaction is intact versus one where the Pd-Ti interaction is severed. Studies were also performed on the relative reactivity of the cationic monometallic (CH2)2(N(t)BuPPh2)2Pd(η(3)-methallyl) catalyst 2 where the Ti from catalyst 1 was replaced by an ethylene group.

Allylic aminations with hindered secondary amine nucleophiles catalyzed by heterobimetallic Pd-Ti complexes.

Phosphinoamide-scaffolded heterobimetallic palladium-titanium complexes are highly effective catalysts for allylic aminations of allylic chlorides with hindered secondary amine nucleophiles. Three titanium-containing ligands are shown to assemble active catalysts in situ and enable catalysis at room temperature. A variety of sterically bulky secondary amines are efficiently allylated in high yields with as little as 1 mol % palladium catalyst.

Synthesis of metal oxide nanoparticles via a robust "solvent-deficient" method.

We report an efficient, general methodology for producing high-surface area metal oxide nanomaterials for a vast range of metal oxides, including at least one metal oxide nanomaterial from nearly every transition metal and semi-metal group in the periodic table (groups 3-4 and 6-15) as well as several from the lanthanide group (see ). The method requires only 2-3 simple steps; a hydrated metal salt (usually a nitrate or chloride salt) is ground with bicarbonate (usually NH4HCO3) for 10-30 minutes to form a precursor that is then either untreated or rinsed before being calcined at relatively low temperatures (220-550 °C) for 1-3 hours. The method is thus similar to surfactant-free aqueous methods such as co-precipitation but is unique in that no solvents are added.

Synthesis of Tungsten Imido Alkylidene Complexes that Contain an Electron-Withdrawing Imido Ligand.

Tungsten NAr alkylidene complexes have been prepared that contain the electron-withdrawing Ar groups 2,4,6-XCH (Ar, X = Cl, Br), 2,6-Cl-4-CFCH (Ar), and 3,5-(CF)CH (Ar). Reported complexes include W(NAr)Cl(dme) (dme = 1,2-dimethoxyethane), W(NAr)(CHCMe), W(NAr)(CHCMe)(OTf)(dme), and W(NAr)(CHCMe)(ODBMP) (DBMP = 4-Me-2,6-(CHPh)CH). The W(NAr)(CHCMe)(ODBMP) complexes were explored as initiators for the polymerization of 2,3-dicarbomethoxynorbornadiene (DCMNBD).

One-pot Solvothermal Synthesis of Well-ordered Layered Sodium Aluminoalcoholate Complex: A Useful Precursor for the Preparation of Porous AlO Particles.

One-pot solvothermal synthesis of a robust tetranuclear sodium hexakis(glycolato)tris(methanolato)aluminate complex Na[Al(OCH)(OCHCHO)] via a modified yet rigorous base-catalyzed transesterification mechanism is presented here. Single crystal X-ray diffraction (SCXRD) studies indicate that this unique Al complex contains three penta-coordinate Al ions, each bound to two bidentate ethylene glycolate chelators and one monodentate methanolate ligand. The remaining fourth Al ion is octahedrally coordinated to one oxygen atom from each of the six surrounding glycolate chelators, effectively stitching the three penta-coordinate Al moieties together into a novel tetranuclear Al complex.

A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel(II) Complexes.

A series of air-stable nickel complexes of the form LNi(aryl) X (L = monodentate phosphine, X = Cl, Br) and LNi(aryl)X (L = bis-phosphine) have been synthesized and are presented as a library of precatalysts suitable for a wide variety of nickel-catalyzed transformations. These complexes are easily synthesized from low-cost NiCl·6HO or NiBr·3HO and the desired ligand followed by addition of 1 equiv of Grignard reagent. A selection of these complexes were characterized by single-crystal X-ray diffraction, and an analysis of their structural features is provided.

Designed single-step synthesis, structure, and derivative textural properties of well-ordered layered penta-coordinate silicon alcoholate complexes.

The controllable synthesis of well-ordered layered materials with specific nanoarchitecture poses a grand challenge in materials chemistry. Here the solvothermal synthesis of two structurally analogous 5-coordinate organosilicate complexes through a novel transesterification mechanism is reported. Since the polycrystalline nature of the intrinsic hypervalent Si complex thwarts the endeavor in determining its structure, a novel strategy concerning the elegant addition of a small fraction of B species as an effective crystal growth mediator and a sacrificial agent is proposed to directly prepare diffraction-quality single crystals without disrupting the intrinsic elemental type.

Synthesis of High Oxidation State Molybdenum Imido Heteroatom-Substituted Alkylidene Complexes.

Reactions between Mo(NAr)(CHR)(MePyr)-(OTPP) (Ar = 2,6--PrCH, R = H or CHCMePh, MePyr = 2,5-dimethylpyrrolide, OTPP = O-2,3,5,6-PhCH) and CH=CHX where X = B(pin), SiMe, -carbazolyl, -pyrrolidinonyl, PPh, OPr, or SPh lead to Mo(NAr)(CHX)-(MePyr)(OTPP) complexes in good yield. All have been characterized through X-ray studies (as an acetonitrile adduct in the case of X = PPh). The efficiencies of metathesis reactions initiated by Mo(NAr)(CHX)(MePyr)(OTPP) complexes can be rationalized on the basis of steric factors; electronic differences imposed as a consequence of X being bound to the alkylidene carbon do not seem to play a major role.

Phase progression of γ-Al2O3 nanoparticles synthesized in a solvent-deficient environment.

Our simple and uniquely cost-effective solvent-deficient synthetic method produces 3-5 nm Al2O3 nanoparticles which show promise as improved industrial catalyst-supports. While catalytic applications are sensitive to the details of the atomic structure, a diffraction analysis of alumina nanoparticles is challenging because of extreme size/microstrain-related peak broadening and the similarity of the diffraction patterns of various transitional Al2O3 phases. Here, we employ a combination of X-ray pair-distribution function (PDF) and Rietveld methods, together with solid-state NMR and thermogravimetry/differential thermal analysis-mass spectrometry (TG/DTA-MS), to characterize the alumina phase-progression in our nanoparticles as a function of calcination temperature between 300 and 1200 °C.

Two polymorphs of 1,8-dichloroanthracene.

A second, monoclinic, polymorph of the title compound, C(14)H(8)Cl(2), has been found. In addition to the structure of this monoclinic form, the structure of the previously described orthorhombic form [Desvergne, Chekpo & Bouas-Laurent (1978). J.

AF and Venous Thromboembolism - Pathophysiology, Risk Assessment and CHADS-VASc score.

Atrial fibrillation (AF) and venous thromboembolism (VTE) are the two most common medical conditions managed with anti-coagulation therapy. Not all the patients with decreased mobility or AF have a similar risk for thromboembolism. The risk factors for venous thromboembolism and thromboembolism associated with AF are described in various studies.

Novel synthesis and structural analysis of ferrihydrite.

Naturally occurring ferrihydrite is both impure and difficult to isolate, so the numerous applications and interesting properties of ferrihydrite have spurred the development of various synthetic techniques. Nearly all techniques are based on the hydrolysis of an iron salt and require careful control of temperature, pH, and concentration. In this Article, we report a new synthetic method which does not require such control and is perhaps the fastest and simplest route to synthesizing ferrhydrite.

Venous thromboembolism in patients with heart failure: in-hospital and chronic use of anti-coagulants for prevention.

Heart failure (HF) is a common clinical syndrome characterized by high morbidity and frequent hospitalizations. HF is an independent and major risk factor for venous thromboembolism (VTE) and VTE occurring in patients with HF carries a worse prognosis. The present review will focus on short and long term role of anti-coagulants in prevention of venous thrombosis in HF patients.