ChemInform Abstract: Warwickites: Electronic Structure and Bonding.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Structure,Properties, and Theoretical Electronic Structure of UCuOP and NpCuOP.

The title compounds are prepared by solid state reaction of U or Np, Cu and/or CuO, and P at 1073—1273 K (evacuated silica tube, 96 h).     

Chemistry and Structure of Diterpenoids: X. Isosteviol Amides

Acylation of amino alcohols with isosteviol chloride, depending on the reactant ratio, leads to formation of either bis-isosteviol derivatives or N-acylation products. Reactions of aromatic diamines with 2 equiv of isosteviol chloride give the corresponding N,N′-bis(isostevioyl) derivatives.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 276–281.Original Russian Text Copyright © 2005 by Al’fonsov, Kataev, Strobykina, Korochkina, Kovylyaeva, Bakaleinik, Beskrovnyi, Gubaidullin, Litvinov, Musin.For communication IX, see [1].     

ChemInform Abstract: Synthesis and Molecular Structure of Disulfane.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Structure and Tautomerism of Cyclopentadiene Derivatives: IX. Synthesis and Structure of Substituted N-Cyclopentadienyl Amidinium Ylides

A procedure has been developed for the synthesis of N-cyclopentadienyl amidinium ylides of the general formula C₅(CO₂Me)₄[ArNC(Ar')NHAr]. According to the X-ray diffraction data, ¹H and ¹³C NMR spectroscopy, and MNDO quantum-chemical calculations, the title compounds have a zwitterionic structure with the positive charge localized over the amidine NÄCÄN triad, and the negative charge, over the cyclopentadiene fragment. The configuration of the amidine moiety is stabilized by additional interaction of the NH hydrogen atom with the negatively charged cyclopentadiene ring (-bonding). The ylides are chiral due to atropoisomerism arising from a high energy barrier (G 298 >25 kcal/mol) to rotation of the Ar' substituent about the ordinary CÄC bond in the amidinium fragment.     

ChemInform Abstract: Synthesis,Structure, and Electronic Structure of CsAgGa2Se4.

The new title compound is prepared from a mixture of AgGaSe₂ (obtained from the elements at 900 °C, 2 d) and CsI in the molar ratio 1:2 (silica tube, Ar, 800 °C, 48 h).     

Phenylhydrazines. Structure and basicity

The main properties of phenylhydrazines are governed by the p-character of the unshared electron pair of the nitrogen of imino group changing in keeping with sp ³ → sp ²-regibridization of its atomic orbitals under the steric and electronic (-I effect of amino group) effect of substituents.     

ChemInform Abstract: Crystal Structure of Difluoroamine.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Homooxacalixarenes: I. Structure,Synthesis, and Chemical Reactions

Data published on the structure, preparation, and chemical reactions of homooxacalixarenes with various number of aromatic fragments and dihomooxabridges in macrocycles were analysed and summarized.     

Injection-moulded α- and β-polypropylenes: I. Structure vs. processing parameters

The paper studies the effects of mould temperature and holding pressure on the structure of neat and β-nucleated isotactic polypropylenes. Commercially available isotactic polypropylene was modified with a β-specific nucleator based on N,N′-dicyclohexylnaphthalene-2,6-dicarboxamide in the concentration of 0.03 wt.%. From both the original material (α-iPP) and the β-nucleated material (β-iPP), dog bone-shaped test specimens were injection-moulded, using two sets of processing parameters. In the T-set the mould temperature was varied within the range of 40-120 °C in 10 °C steps, while in the P-set the holding pressure was changed from 5 to 13 MPa in 1 MPa steps. Other processing parameters were kept on the same level. Polarized-light microscopy showed a strong effect of mould temperature on the morphology of α-iPP specimens; the skin thinned out and the spherulite size increased with mould temperature rise. On the other hand, in the case of β-iPP only the skin thickness was correspondingly affected, while the spherulite size remained virtually constant, independent of the mould temperature changes. At the same structure level, both α-iPP and β-iPP specimens were insensitive to holding pressure variations. Polymorphic composition derived from wide-angle X-ray scattering displayed similar range of changes induced by variations of the processing parameters for both materials. The increase of mould temperature positively influenced the crystallinity and the β-form content, particularly in the skin of specimens. On the contrary, higher holding pressure depressed the crystallinity proportionally within the bulk of specimens.     

Cyclic Arylene Sulfide Macromolecules: Synthesis,Structure and Properties.

Synthesis, X-ray structure, ring-opening polymerization macrocyclic phenylene sulfides and their role in chemistry and technology of polyarylene sulfides are discussed.     

C-Metallated reformatsky intermediates. Structure and reactivity.

¹³C-NMR analysis of the Reformatsky intermediates from t-b$\text{u}$tyl-α-bromo acetate, t-b$\text{u}$tyl-α-bromo isobutyrate and t-b$\text{u}$tyl-α-bromo pr$\text{o}$pionate have evidenced C-metallated species. Their ability to act as n$\text{u}$cleophilic reagents under mild conditions and their selectivity towards h$\text{a}$logen-and oxygen containing electrophiles is reported.     

1,3,2,4-Oxaazaphosphatitanetidine. Structure and Properties

The interaction of 1,3,2,4 -oxaazaphosphatitanetidines with chlorides of aluminium and zirconium, alcohols, piperidine and R₂NBr (R=SiMe₃) has been studied. The reaction routes have been determined with NMR spectra and X-ray structure analyses.