High conversion of olefins to cis-diols by non-heme iron catalysts and H2O2

Efficient and highly stereoselective oxidation of olefins to cis-diols as the major product is obtained by using biomimetic non-heme FeII catalysts in combination with H2O2.     

The role of intermolecular and molecule-substrate interactions in the stability of alkanethiol nonsaturated phases on Au(111)

The structure and stability of alkanethiols self-assembled on Au(111) have been studied as a function of the molecular chain length by means of atomic force microscopy (AFM) and grazing incidence X-ray diffraction (GIXD). Below saturation, phases consisting of molecules with different tilt angles and periodicities are formed. Differences in the mechanical stability of these phases are revealed by AFM experiments and discussed in terms of the competition between intermolecular and molecule-substrate interactions as a function of chain length. For long molecules, intermolecular interactions play a dominant role which stabilizes the formation of closed packed 30 degrees tilted ( radical 3x radical 3)R30 degrees structures. For short molecules, the van der Waals interaction with the gold substrate favors the formation of a 50 degrees tilted phase in which the molecules are arranged in a rectangular configuration.     

Iterative method generated by inverse interpolation with additional evaluations

An improvement of the iterative methods based on one point iteration function, with or without memory, using n points with the same amount of information in each point and generated by the inverse polynomial interpolation is given. The adaptation of the strategy presented here gives a new iteration function with a new evaluation of the function which increases the local order of convergence dramatically. This method is generalized to r evaluations of the function. This method for the computation of solutions of nonlinear equations is interesting when it is necessary to get high precision because it provides a lower cost when we use adaptive multi-precision arithmetics. AMS subject classification 65H05     

Angle-resolved photoemission studies of C (2 × 2) oxygen overlayer on Ni (100)

We report angular-resolved photoemission experiments with 44 eV p-polarized radiation on a C (2 × 2) oxygen overlayer on Ni as a function of polar angle θ. A photoemission calculation using a single step model has been performed. We show that with our present expemental equipment, it is very difficult to discriminate the p_z and p_x,p_y states of oxygen, because of hybridization with Ni s-p levels, except at some high symmetry points for which partially polarized light may give a measurable distinction.     

The γ‐form of n‐eicosanol

In the crystal of the title compound, C₂₀H₄₂O, the mol­ecules are packed in layers parallel to the (100) plane. The alkyl chains are parallel to the [30] direction and these molecular chains are hydrogen‐bonded into chains parallel to the c axis. All C—C bonds of the alkyl chain show an antiperiplanar (trans) conformation, with a slight deviation from the ideal value (180°) in the C—C bonds close to the hydrogen bonds. The length of the alkyl chain is 27.92 (2) Å and the tilt angle is 59.7 (2)°.     

Didehydrophenanthrenes: structure, singlet-triplet splitting, and aromaticity

In this work, we explore the geometries, relative stabilities, singlet-triplet (S-T) splittings, and local aromaticities of the 25 possible didehydrophenanthrenes (DDPs) at the BLYP/6-31G(d) level. The main aim is to understand their molecular structure and stability in terms of the electronic structure. To this end, we analyze the changes induced by didehydrogenation in molecular structure and local aromaticity and we investigate the coupling strength between radical centers in DDPs through the evaluation of S-T splittings. Further evidence for the repulsive character of the H-H interactions in phenanthrene's bay region is gained from the relative energies of the triplet states of the different DDPs.