Diferric oxo-bridged complexes of a polydentate aminopyridyl ligand: synthesis,structure and catalytic reactivity

The catalytic reactivity of a group of diferric oxo-bridged complexes (1–3) of a tetradentate ligand (bpmen = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-1,2-diaminoethane) toward alkane hydroxylation has been evaluated. Among the three complexes, the µ-oxo diiron(III) complex [Fe(bpmen)(µ-O)FeCl₃] (1) has been synthesized for the first time. The complex 1 has been characterized by spectroscopic analysis and X-ray crystallography. At room temperature, the µ-oxo diiron(III) complexes 1–3 have been found to be useful catalysts in hydroxylation of alkanes with m-chloroperbenzoic acid as oxidant. [Fe(bpmen)(µ-O)FeCl₃] (1) has been found to be the most active catalyst. Moreover, the catalytic ability of the complexes in the oxidation of alcohols to ketones with hydrogen peroxide at room temperature has also been investigated.     

Intramolecular Acylation During Acid Chloride Formation of Some o-Styryl Phenoxyacetic Acids

o-Isopropenyl phenoxyactic acids 1 and 8 on treatment with thionyl chloride followed by aqueous workup furnished the acylated products 4 and 9 in moderate yields. The corresponding acid chlorides could also be cyclised with stannic chloride. The acid chlorides from 10 and 11 however did not undergo cyclisation.     

Mathematical structure of topological solitons due to the Sine-Gordon Equation

This paper studies the mathematical structure of the kink soliton solution to the generalized dispersive SGE. All derivatives are found and the trigonometric functions of the kink are found for a generalized height.     

Constraint on three-Higgs-doublet model parameters by b → sγ decay considering possibility of the fourth generation in quark sector

Weak radiative B-meson decay has been studied to find plausible constraints on the complex coupling constants that arise from the diagonalization of the charged scalar mixing matrix in Weinberg three-Higgs-doublet model considering possibility of the fourth generation in quark sector. We examined the range of these complex coupling constants taking in to account corrections up to leading QCD logarithms, using evolution of fourth-generation CKM matrix with CP violation phase approximately equal to zero. Range of the mass of fourth generation down-type quark b′ and that of fourth-generation uptype quark t′ have been taken with due consideration of the constraint imposed by the present experimental value of theρ parameter keeping in view the mass difference of the fourth-generation quark doublet.     

1-Soliton solution of the generalized Camassa–Holm Kadomtsev–Petviashvili equation

An exact 1-soliton solution of the generalized Camassa–Holm Kadomtsev–Petviashvili equation is obtained in this paper by the solitary wave ansatze. This solution is a generalized form of the solution that is obtained in earlier works.     

The Jacobian of a nonorientable Klein surface, II

The aim here is to continue the investigation in [1] of Jacobians of a Klein surface and also to correct an error in [1].     

Numerically effectiveness and principal bundles on Kähler manifolds

Let E _G be a holomorphic principal G-bundle over a compact connected Kähler manifold, where G is a connected complex reductive linear algebraic group. Consider a line bundle over E _G /P corresponding to a character of P, where P is a parabolic subgroup of G. We give conditions for this holomorphic line bundle to be numerically effective.     

A Least-Squares Mixed Scheme for the Simulation of Two-Phase Flow in Porous Media on Unstructured Grids

A least-squares mixed formulation is developed for simulation of two-phase flow in porous media. Such problems arise in petroleum applications and ground-water flow. An adaptive strategy based on the element residual as an error indicator is developed in conjunction with unstructured remeshing and tested for the two-phase flow of oil and water. An element-by-element conjugate-gradient scheme (EBE-CG) is compared to a band solution algorithm.     

Influence of multiwall carbon nanotubes on morphology and electrical conductivity of PP/ABS blends

Polypropylene (PP) and acrylonitrile‐butadiene‐styrene (ABS) blends with multiwall carbon nanotubes (MWNT) were prepared by melt mixing. PP/ABS blends without MWNT revealed coarse co continuous structures on varying the ABS content from 40 to 70 wt %. Bulk electrical conductivity of the blends showed lower percolation threshold (0.4–0.5 wt %) in the 45/55 co continuous blends whereas the percolation threshold was between 2 and 3 wt % in matrix‐particle dispersed morphology of 80/20 blends. Interestingly, droplet size was observed to decrease with addition of MWNT above percolation threshold in 80/20 blends. Further, the bulk electrical conductivity was found to be dependent on the melt flow index of PP. The non‐polar or weakly polar nature of blends constituents resulted in the temperature independent dielectric constant, dielectric loss, and DC electrical conductivity. Rheological analysis revealed the formation of 3D network‐like structure in 80/20 PP/ABS blends at 3 wt % MWNT. An attempt was made to understand the relationship between rheology, morphology, and electrical conductivity of these blends. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2286–2295, 2008