Direct vinylation and difluorovinylation of arylboronic acids using vinyl- and 2,2-difluorovinyl tosylates via the Suzuki-Miyaura cross coupling

General reaction conditions were developed for the Pd(0)-catalyzed Suzuki-Miyaura coupling reaction of aryl boronic acids with a simple electrophilic vinylation reagent, vinyl tosylate, providing access to styrene derivatives in good yields. The easily accessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology was expanded to provide a facile and straightforward approach for the introduction of a gem-difluorovinyl substituent onto an aromatic ring using the similar and also readily available 2,2-difluorovinyl tosylate as the electrophilic complement.     

Formation of an ion-pair molecule with a single NH(+)...Cl(-) hydrogen bond: Raman spectra of 1,1,3,3-tetramethylguanidinium chloride in the solid state, in solution, and in the vapor phase

Some ionic compounds (salts) form liquids when heated to temperatures in the range of 200-300 degrees C. They may be referred to as moderate temperature ionic liquids. An example of such a compound is the 1,1,3,3-tetramethylguanidinium chloride, [TMGH]Cl, melting at approximately 212 degrees C. The chemistry of this compoundcontaining a dimeric ion-pair "molecule"was investigated in the solid state, in solutions in water and ethanol, and in the vapor phase, based on ab initio molecular orbital density functional theory (DFT)-type calculations with 6-311+G(d,p) basis sets. Calculations on the monomeric [TMGH] (+) ion and the dimeric chloride ion-pair salt converged to give geometries near the established crystal structure of [TMGH]Cl. The structures and their binding energies are given as well as calculated vibrational harmonic normal modes (IR and Raman band wavenumbers and intensities). Experimentally obtained Raman scattering spectra are presented and assigned, by comparing to the quantum mechanical calculations. It is concluded that dimeric molecular ion pairs with four N-H (+)...Cl (-) hydrogen bonds probably exist in the solutions and are responsible for the relatively high solubility of the "salt" in ethanol. It was discovered that the compound can be easily sublimed by heating to about 200-230 degrees C. In the Raman spectrum of the vapor at 225 degrees C, a characteristic strong band at 2229 cm (-1) was found and interpreted to show that the gas phase consists of monomeric ion-pair "molecules" held together by a single N-H (+)...Cl (-) hydrogen bond, the stretching band of which is causing the band.     

A monolithic PNGase F enzyme microreactor enabling glycan mass mapping of glycoproteins by mass spectrometry

We demonstrate a simple and rapid single-step method to fabricate an enzyme microreactor incorporating the N-glycosidase PNGase F (peptide-N-glycosidase F) into a porous polymer-based monolith. The monolith is contained in a capillary format, while the enzyme reactor is ready to use within 1 h of preparation. The monomers making up the monolith, including N-acryloxysuccinimide for covalent immobilization of the enzyme, are mixed with PNGase F and introduced into the column by capillary force for polymerization/immobilization. Glycoproteins (ribonuclease B, asialofetuin, alpha1-acid glycoprotein, and ovalbumin) perfused through the PNGase F reactor were shown to be effectively deglycosylated on a time-scale of seconds/low minutes using low nanogram to microgram per microliter concentration (corresponding to a total sample consumption of 0.1-20 microg of a glycoprotein). The reactor enzyme activity was shown to be reproducible for at least 8 weeks when used and stored at room temperature. Evaluation was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.     

Surface bio-magnetism on bacterial cells adhesion and surface proteins secretion

Extensive research works have been done on using magnetic fields on biological organism, but the results till date have been controversial [D.O. Carpenter, S. Ayrapetyan (Eds.), Biological Effects of Electric and Magnetic Fields, vol. 1, Academic Press, San Diego, 1994]. In spite of this, the study of surface magnetic effects on bacterial adhesion and cell growth has not been rigorously explored. The effects of surface magnetism, using perpendicularly polarized magnetic media, are evaluated on Bacillus licheniformis, a widely used bacterium in brewery [L. Kandra, a-Amylases of medical and industrial importance. J. Mol. Struct. (Theochem.), in press] and pharmaceutical [H. Ikram-ul et al., Production of alph amylase by Bacillus licheniformis using an economical medium. Bioresour. Technol. 87 (2003) 57-61] industries, by observing its adhesion and growth behavior. At different spin directions, we are able to observe a change on the biofilm formation, protein synthesis, and cell growth rate. Given that surface energy can easily penetrate through cells, this approach is an advantage over existing techniques that require direct physical contact to target cells. It also presents a new technique to cell adhesion and synthesis of surface proteins.     

Experimental realization of optimal asymmetric cloning and telecloning via partial teleportation

We report an experimental realization of both optimal asymmetric cloning and telecloning of single photons by making use of partial teleportation of an unknown state. In the experiment, we demonstrate that, conditioned on the success of partial teleportation of single photons, not only the optimal asymmetric cloning can be accomplished, but also one of two outputs can be transferred to a distant location, realizing the telecloning. The experimental results represent a novel way to achieve quantum cloning and may have potential applications in the context of quantum communication.     

Fractional quantum Hall states of atoms in optical lattices

We describe a method to create fractional quantum Hall states of atoms confined in optical lattices. We show that the dynamics of the atoms in the lattice is analogous to the motion of a charged particle in a magnetic field if an oscillating quadrupole potential is applied together with a periodic modulation of the tunneling between lattice sites. In a suitable parameter regime the ground state in the lattice is of the fractional quantum Hall type, and we show how these states can be reached by melting a Mott-insulator state in a superlattice potential. Finally, we discuss techniques to observe these strongly correlated states.     

A note on a local effect at the Schwarzschild sphere

Passage of the Schwarzschild radius is shown to be locally measurable by a sign change in a certain scalar. In the Kerr solution this scalar changes sign at the stationary limit. This is an example of the use of a coordinate-invariant method, based on the curvature tensor and a finite number of its covariant derivatives, for investigating gravitational fields.     

Recent advances in bimetallic electrocatalysts for oxygen reduction: design principles,structure-function relations and active phase elucidation

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