Formation of a high coverage (3 x 3) NO phase on Pd(111) at elevated pressures: interplay between kinetic and thermodynamic accessibility

Using in situ polarization modulation infrared reflection absorption spectroscopy and density functional theory calculations, a new high-coverage monomeric NO adsorption state on Pd(111) was observed and proposed to have a (3 x 3)-7NO structure. Formation of this high coverage NO phase was found to take place only at elevated pressure and temperature conditions showing that some of the accessible thermodynamic equilibrium states at elevated temperatures and pressures are thermodynamically unfavorable or kinetically hindered at lower temperatures and pressures. Our results emphasize the danger of extrapolating results from traditional surface science experiments performed under ultrahigh vacuum to elevated temperature and pressure conditions encountered in heterogeneous catalysis.     

Halogen-Bonded BODIPY Frameworks with Tunable Optical Features**

The ability to tune the optical features of BODIPY materials in the solid state is essential for their photorelated application and requires efficient control of the crystal packing. In this study, such control of BODIPY supramolecular assemblies was achieved by deliberate design and synthesis of a BODIPY containing a strong halogen-bond (XB) acceptor (−NO₂) and donor (I, Br) to mediate XB interactions. The di-halogenated structures formed isostructural mono-coordinate motif B3 , B4 (1D tubular structure) and symmetric bifurcated motif B4-II (1D zigzag chains structure) through N−O⋅⋅⋅I, Br XB interactions. These XB interactions promote singlet-to-triplet intersystem crossing and triplet-to-singlet reverse intersystem crossing due to partial delocalization of oxygen electrons onto Br and I, which leads to unexpected fluorescence enhancement of B4-II . Finally, the indirect optical band gaps of B3 , B4 and B4-II were amenable to tuning in the range of 1.85–2.50 eV by XB-driven crystal packings.     

Laguerre matrix method with the residual error estimation for solutions of a class of delay differential equations

In this study, a practical matrix method based on Laguerre polynomials is presented to solve the higher‐order linear delay differential equations with constant coefficients and functional delays under the mixed conditions. Also, an error analysis technique based on residual function is developed and applied to some problems to demonstrate the validity and applicability of the method. In addition, an algorithm written in Matlab is given for the method. Copyright © 2013 John Wiley & Sons, Ltd.     

2D atomic mapping of oxidation states in transition metal oxides by scanning transmission electron microscopy and electron energy-loss spectroscopy

Using a combination of high-angle annular dark-field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy in an aberration-corrected transmission electron microscope we demonstrate the possibility of 2D atom by atom valence mapping in the mixed valence compound Mn3O4. The Mn L(2,3) energy-loss near-edge structures from Mn2+ and Mn3+ cation sites are similar to those of MnO and Mn2O3 references. Comparison with simulations shows that even though a local interpretation is valid here, intermixing of the inelastic signal plays a significant role. This type of experiment should be applicable to challenging topics in materials science, such as the investigation of charge ordering or single atom column oxidation states in, e.g., dislocations.     

New asymmetric generalizations of the Filbert and Lilbert matrices

Periodica Mathematica Hungarica - Two new asymmetric generalizations of the Filbert and Lilbert matrices constructed by the products of two Fibonacci and Lucas numbers are considered, with...     

Measurement uncertainty in testing for antimicrobial activity on textile materials

Measurement uncertainty is widely recognized among physicists and chemists, but is a relatively new concept to many microbiologists. Generally, available documents about measurement uncertainty in microbiological testing are applicable to food and water microbiology. Two quantitative methods for evaluation of antimicrobial activity of textile materials are used commonly in textile laboratories. Methodology and expression of results for the two methods are similar; thus, calculation and expression of measurement uncertainty for results obtained by these test methods are also similar. This contribution describes the way in which measurement uncetainty for these methods can be evaluated and reported.     

Reluctance of 4-chloro-5-metalla-1,3,2-diazaborolines to undergo metal halide beta-elimination: an opportunity for C-functionalization of 1,3,2-diazaborolines

N,N'-Bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene reacts with dichlorophenylborane, affording the N,N'-bis(2,6-diisopropylphenyl)-2-phenyl-4-chloro-1,3,2-diazaboroline in a one-step process. The addition of lithium diisopropylamide gives rise to the 4-chloro-5-lithio-1,3,2-diazaboroline derivative, which cleanly undergoes a transmetalation reaction with TiCl4 x 2 THF. Both the lithium and titanium complexes are stable with respect to metal chloride elimination and have been characterized by multinuclear NMR spectroscopy and by single-crystal X-ray diffraction studies. These findings open an avenue for the C-functionalization of 1,3,2-diazaborolines.     

The generalized Lilbert matrix

We introduce a generalized Lilbert [Lucas-Hilbert] matrix. Explicit formulæ are derived for the LU-decomposition and their inverses, as well as the Cholesky decomposition. The approach is to use q-analysis and to leave the justification of the necessary identities to the q-version of Zeilberger’s celebrated algorithm.