1H NMR assignment corrections and 1H, 13C, 15N NMR coordination shifts structural correlations in Fe(II), Ru(II) and Os(II) cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline

¹H, ¹³C and ¹⁵N NMR studies of iron(II), ruthenium(II) and osmium(II) tris‐chelated cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline of the general formula [M(LL)₃]²⁺ (M = Fe, Ru, Os; LL = bpy, phen) were performed. Inconsistent literature ¹H signal assignments were corrected. Significant shielding of nitrogen‐adjacent protons [H(6) in bpy, H(2) in phen] and metal‐bonded nitrogens was observed, being enhanced in the series Ru(II) → Os(II) → Fe(II) for ¹H, Fe(II) → Ru(II) → Os(II) for ¹⁵N and bpy → phen for both nuclei. The carbons are deshielded, the effect increasing in the order Ru(II) → Os(II) → Fe(II). Copyright © 2010 John Wiley & Sons, Ltd.     

The Number of Monochromatic Schur Triples

In this paper, we prove that in every 2-coloring of the set {1, , N } = R B, one can find at least N² / 22 + O(N) monochromatic solutions of the equation x + y = z. This solves a problem of Graham et al. .     

Stereostructure of mycoheptin A2

The absolute configurations of all the stereogenic centers of the antibiotic mycoheptin A₂ were established upon previously elaborated general procedure, consisting of DQF‐COSY, NOESY, ROESY, HSQC and HMBC experiments as major tools. The structure of mycoheptin A₂ without stereochemistry of its aglycone has been reported before. Copyright © 2012 John Wiley & Sons, Ltd.     

The Cubical Cohomology Ring: An Algorithmic Approach

A cohomology ring algorithm in a dimension-independent framework of combinatorial cubical complexes is developed with the aim of applying it to the topological analysis of high-dimensional data. This approach is convenient in the cup-product computation and motivated, among others, by interpreting pixels or voxels in digital images as cubes. The S-complex theory and so called co-reductions are adopted to build a cohomology ring algorithm speeding up the algebraic computations.     

Pseudodifferential parabolic equations in uniform spaces

The paper is devoted to local and global solvability in locally uniform spaces and to the existence of a global attractor for a parabolic problem containing fractional power of the minus Laplace operator. Several useful technical tools and estimates are also collected in this paper.     

Characterization of CaTi0.9Fe0.1O3/La0.98Mg0.02NbO4 composite

A composite of CaTi_0.9Fe_0.1O₃ and electrolyte material, i.e. magnesium doped La_0.98Mg_0.02NbO₄ was prepared and studied. The phase content and the sample microstructure was examined by an X-ray diffraction method and scanning electron microscopy. EDS measurements were done both for composite samples and the diffusion couple. The electrical properties were studied by four terminal DC method. The high-temperature interaction between the two components of the composite has been observed. It has been suggested that lanthanum diffused into the perovskite phase and substituted for calcium whereas calcium and niobium formed the Ca₂Nb₂O₇ pyrochlore phase. At 1500°C very large crystallites of the pyrochlore were observed. Regardless of strong interaction between the composite components, its total conductivity was weakly dependent on the sintering temperature.     

Functionalization of some benzylthioarylboronic acids by benzylic lithiation of their N‐butyldiethanolamine esters or lithium (triisopropoxy)borates

The reaction of benzylthioarylboronic acids protected as N‐butyldiethanolamine esters or as triisopropoxyborates with organolithium bases or lithium diisopropylamide (LDA) has been investigated. The benzylic lithiation occurs selectively using LDA at − 68 °C. The stability of the resultant borio‐lithio intermediates is strongly influenced by the position of the boron atom in the phenyl ring. The reaction with various electrophiles affords new arylboronic acids substituted in the benzylic position. Copyright © 2011 John Wiley & Sons, Ltd.     

Calixarene complexes with metal ions

Selected complexes of metal ions are presented showing their syntheses and possible applications, an attention was paid to their usefulness in chemosensors design and in the environmental protection.     

Synthesis of new thiazole-2, -4, and -5-yl-(amino)methylphosphonates and phosphinates: unprecedented cleavage of thiazole-2 derivatives under acidic conditions

An efficient and reliable synthesis of new thiazole-(amino)methylphosphonic, phosphinic acids, and phosphine oxides is reported. The synthetic protocol is based on nucleophilic addition of phosphorous species to thiazole derived imines. Unexpectedly, it was discovered that heating of thiazole-2-yl-(amino)methylphosphonates and phosphinates with aqueous HCl leads to their decomposition resulting in a rupture of the C-P bond, rejecting of the phosphorus containing fragment and formation of the corresponding secondary N-(thiazole-2-yl-methyl)-alkylamines. Two alternative mechanisms for this cleavage are postulated.