Composition of thiacalix[4]arene complexes with monovalent metal ions in the gas phase: MALDI mass spectrometry

MALDI-TOF mass spectrometry was used to study the reaction of p-tert-butylthiacalix[4]arene (1) and a number of its derivatives disubstituted at the lower rim (2—9) with monovalent metal salts (Li, Na, K, Cs, Cu, Ag) in the gas phase. It was shown that the thiacalixarenes under study bind the metal ions through the substitution of hydrogen atoms of the hydroxy groups. The reactions of silver and copper salts with the thiacalix[4]arenes were found to form the cluster ions, which represent the macrocycle dimers with several metal ions, while the formation of such clusters is impossible in the case of alkali metal salts. The peak intensities of the cluster ions increase in the weakly basic medium, reaching in some cases 100%.     

Alkylation of 1-alkoxy-3-methyl-1-triazene 2-oxide sodium salts

1-Alkoxy-3-methyl-1-triazene 2-oxide sodium salts react with chloromethyl methyl sulfide to give a mixture of 1-alkoxy-3-methyl-3-(methylthiomethyl)-1-triazene 2-oxides and 3-alkoxy-1-methyl-3-(methylthiomethyl)-1-triazene 2-oxides. The reaction of these triazene oxide sodium salts with 3,3-dialkyl-1-chloromethoxy-1-triazene 2-oxides produces a complex mixture of product bearing the oxytriazene moieties of the starting alkoxy-1-triazene 2-oxides bonded with the methylene group as a key structural fragment.     

Synthesis and structural identification of 10-vertex closo-nickelacarborane with cage carbon atoms in unusual polyhedral positions

Russian Chemical Bulletin -     

A note on computational blood rheology

We briefly present some numerical simulations for a generalized Newtonian model describing the shear-thinning behavior of blood in a realistic 3D geometry. Results are compared with those obtained using the Newtonian model     

Tails of Le´vy Measure of Geometric Stable Random Variables

We establish precise logarithmic asymptotics around the origin for the Le´vy measure of geometric stable (GS) random variables. This implies, in particular, exponential rate of convergence in series representation of GS random variables.     

MacNeille Completions of D-Posets and Effect Algebras

Our main result is stating and proving a necessary and sufficient condition forD-poset and effect algebras to have MacNeille completions.     

Synthesis of C-29-phosphonium derivatives of 3,28-diacetoxylup-20(29)-en-30-oic acid

3β,28-Diacetoxylup-20(29)-en-30-oic acid (obtained via oxidation of betulin diacetate) enters the addition reaction with P—H-phosphonium salts (triarylphosphonium trifluoroacetates) under mild conditions to afford β-carboxyalkylphosphonium salts. Structure and composition of the resulting compounds were confirmed by NMR and IR spectroscopy, mass spectrometry, and elemental analysis.

     

4-Het(aryl)-2-pyrrolidone-3(5)-carboxylic acid alkyl(hetaryl)idenecarbohydrazides: synthesis and structure

Russian Chemical Bulletin - 4-Het(aryl)-2-pyrrolidone-3(5)-carboxylic acid hydrazides react with aromatic aldehydes, acetone, and acetophenone to give new representatives of...