Structures of two ketals derived from a pentacyclic cage diketone

The structure of a compound derived from a symmetrical cage diketone in which one of the ketone C=O groups has been converted into a ketal is reported. An investigation into reasons for the selective functionalization resulted in the isolation of acis, cisoid, cis linear triquinane derivative in which both ketones are converted to ketals that share a transannular oxygen atom. Crystal data:2, monoclinic,P2₁/c,a=7.6298(9),b=7.673(3),c=22.125(3)Å,=97.59(1)°,V=1283.9(5)ų, andR=0.048 (1001 reflections);4, triclinic,P¯1,a=7.3864(9),b=9.6362(9),c=10.3889(9)Å,=75.749(6),=76.300(8), =83.100(8)°,V=694.8(4)ų, andR=0.088 (1284 reflections).     

Electron impact mass spectra of 1-methyl-3-(2-benzothiazolylhydrazono)-2-indolinones

A study of the fragmentation of l-methyl-3-(2-benzothiazolylhydrazono)-2-indolinones on electron impact reveals that the major processes involve N? N bond fission and the competing loss of CO from the molecular ion.     

Electro-chromatography in the study of ions

Summary Change of concentration of electrolyte such as sodium chloride, potassium chloride, ammonium chloride and potassium bromide has a marked effect on the direction of migration of Cd. A very cheap set incorporating a number of Durrum'S units suitable for separation of a large number of different types of mixtures of ions has been devised.     

Closest packing in dense oxides: The structure of a polymorph of Co3(AsO4)2

Crystals of Co₃(AsO₄)₂ were grown from the melt of a mixture of Co₂As₂O₇ and As₂O₅. The crystals are isostructural with Mg₃(AsO₄)₂ and are tetragonal with a = 6.858(2), c = 18.872(5) Å, Z = 6, and space group $\text{I}\text{4}\text{2d}$. A total of 1048 independent reflections were measured by diffractometer and used in the full-matrix refinement to a final R value of 0.069. The structure contains two distinct AsO₄ groups. Two of the cobalt ions are octahedrally coordinated and a third occupies a $\text{4}$ site with four short and four long CoO distances. The crystal structure of Co₃ (AsO₄)₂ is not based on the continuous three-dimensional closest packing of oxygen atoms. Nevertheless the number of oxygen atoms per cubic centimeter is 5.4 × 10²², which falls in the range of values for hexagonal and cubic closest packed structures. A better measure of the degree to which closest packing is achieved by a structure is suggested. It is based on an analysis of the polyhedra of oxygen atoms which surround each of the oxygen atoms in a structure and their relation to the polyhedra in ideally closest packed structures. In order to facilitate the analysis, polytopes of 11- and 12-vertex polyhedra were studied. A new decahexahedral 11-vertex polyhedron was found.     

Thermal behaviour of bisitaconimide and reactive diluent blends

Thermal behaviour of blends based on N,N'-bis(4-itaconimidophenyl) ether (IE) and 4,4'-bis(4-allyl-2-methoxyphenoxy) benzophenone (R₁) or 4,4'-bis(2-allylphenoxy) benzophenone (R₂) are described in this paper. The reactive diluent content was varied from 5-50% (mass/mass) in these blends. A decrease in the melting point and exothermic peak temperature was observed with increasing mass percent of reactive diluent. Thermal stability of blends was affected at high mass percentage of reactive diluents. This revised version was published online in August 2006 with corrections to the Cover Date.