Synthesis and spectral properties of new 3,3’-bis(dipyrrolylmethene) with acetylene spacer

Bis(2,4,7,9-tetramethyl-8-ethyldipyrrolylmethen-3-yl)acetylene dihydrobromide (H₂L·2HBr), new bis(dipyrrolylmethene), in whose molecule dipyrrolylmethene domains were connected through 3,3′-carbon atoms of internal pyrrole nuclei by acetylene spacer, were synthesized by original procedure. The compound was characterized by element analysis, IR, ¹H NMR, and electronic spectroscopy. The comparative analysis of spectral properties shows the reduction of the basicity of H₂L ligand in comparison with the structural analogs, which contain internal methylene spacer. The quantum-chemical simulation showed that the rigid acetylene spacer gives linear structure to the H₂L molecule in contrast to the spiral-shaped geometry of structural analogs with -CH₂- spacer.     

Synthesis and some properties of heteronuclear platinum and palladium carbonyl clusters

Heteronuclear clusters of general formula [Pt_xPd_y(CO) _z] were synthesized by reaction of CO with PtCl₄ + PdCl₂ solutions in 95% ethanol at room temperature and atmospheric pressure. The products isolated were analyzed by IR spectroscopy, thermogravimetry, and X-ray powder diffraction.     

Nickel-Zinc Battery with Nickel Oxide Electrode Made of Spherical Nickel Hydroxide on Foamed Nickel Support

Electrochemical and working characteristics of a nickel-zinc battery with nickel oxide electrode made of spherical nickel hydroxide on foamed nickel support were determined.     

Oxidation of substituted phenols with chlorine dioxide

Chlorine dioxide was used to oxidize sterically hindered phenols and their derivatives (2,6-di-tertbutylphenol, 2,6-diisobornylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,6-diisobornyl-4-methylphenol, and 3,5-diisobornyl-4-hydroxybenzaldehyde) in organic solvent.     

Enthalpy of formation of dimethyltriazanium chloride

Conclusions We determined the enthalpies of solution (5.53 ± 0.03 kcal/mole) and formation (21.7 ± 0.28 kcal/mole) of dimethyltriazanium chloride.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2392–2394, October, 1981.     

ON QUOTIENTS OF BRAID GROUPS

ABSTRACT.

Let G be the group ?[t, t ^?1] x ?. By studying the action of the braid group B_n on the set Gⁿ , we obtain representations of B_n into a wreath product of the symmetric group and the general linear group over ?[t, t ^?1]. This in particular recovers the Burau representation of the braid group. Furthermore, some quotients of the braid group are obtained by using the representations found.