A.M. Moustafa

1'-Methyl-4'-(4-methyl-phen-yl)dispiro-[indane-2,3'-pyrrolidine-2',3''-indoline]-1,2''-dione.

In the title molecule, C27H24N2O2, the pyrrolidin-2-one ring is almost planar (r.m.s. deviation = 0.003 Å), the pyrrolidine ring has an envelope conformation (the N atom is the flap atom) and the cyclopentanone ring is twisted about the Cq—Cm bond (q = quaternary and m = methylene). The ketone O atoms are directed to opposite sides of the molecule. Supramolecular chains along the a axis are formed in the crystal packing mediated by N—H⋯N and C—H⋯O interactions. These are connected into layers in the ab plane via C—H⋯π interactions.

Application of Rietveld Method to the Structural Characteristics of Substituted Copper Ferrite Compounds

A series of ferrite samples of the chemical composition Cu 0.7 (Zn 0.3-x Mg x )Al 0.3 Fe 1.7 O4 [x=0.05, 0.1, 0.15 and 0.2], prepared by ceramic technique at 1000 °C, were found to have cubic spinel structure. On applying the full pattern fitting of Rietveld method using FullProf program, the exact coordinates of atoms, the unit cell dimensions, the atom occupation factors, isotropic temperature factors, the profile shape parameters as well as the interatomic distances have been determined. It was found that the lattice parameter decreases with increasing the Mg content. Also the variation of the cation distribution has been discussed on the basis of site preference, size and valence of the substituting cations. The low isotropic microstrain values obtained during the refinement process may be attributed to the method of the preparation in which the samples after the last sintering were treated by annealing.

5′′-Benzyl­idene-5-chloro-1′,1′′-dimethyl-4′-phenyl­dispiro­[indoline-3,2′-pyrrolidine-3′,3′′-piperidine]-2,4′′-dione

The title compound, C30H28ClN3O2, features two spiro links, one connecting the piperidine and pyrrolidine rings, and the other connecting the pyrrolidine ring and indole residue. The configuration about the ethene bond is E. The piperidine ring adopts a half-chair conformation where the C atom connected to the spiro-C atom lies 0.713 (3) Å out of the plane of the remaining five atoms (r.m.s. deviation = 0.086 Å). The pyrrolidine ring has an envelope conformation with the flap atom being the methylene C atom. Centrosymmetric eight-membered {⋯HNCO}2 amide synthons feature in the crystal packing. These are consolidated into a three-dimensional architecture by phenyl–pyrrolidine C—H⋯N and chlorobenzene–pyrrolidine-bound phenyl C—H⋯π interactions.

5-Chloro-5′′-[4-(di­methyl­amino)­benzyl­idene]-4′-[4-(di­methyl­amino)­phen­yl]-1′,1′′-di­methyl­dispiro­[indoline-3,2′-pyrrolidine-3′,3′′-piperidine]-2,4′′-dione

The title compound, C34H38ClN5O2, has spiro links connecting the pyrrolidine ring and indole residue, as well as the piperidine and pyrrolidine rings. A half-chair conformation is found for the piperidine ring with the C atom connected to the spiro-C atom lying 0.738 (4) Å out of the plane of the remaining five atoms (r.m.s. deviation = 0.0407 Å). The methylene C atom is the flap in the envelope conformation for the pyrrolidine ring. In the crystal, supramolecular chains are sustained by alternating eight-membered {⋯HNCO}2 and 14-membered {⋯HC5O}2 synthons. Chains are connected into a three-dimensional network by (pyrrolidine-bound phenyl-methyl)C—H⋯π(pyrrolidine-bound phenyl) edge-to-face interactions.

5-Chloro-5′′-(4-chloro­benzyl­idene)-4′-(4-chloro­phen­yl)-1′,1′′-dimethyldi­spiro­[indoline-3,2′-pyrrolidine-3′,3′′-piperidine]-2,4′′-dione

The racemic title compound, C30H26Cl3N3O2, comprises two spiro links, the first connecting the piperidine and pyrrolidine rings and the other connecting the indole and pyrrolidine rings. The piperidine ring adopts a half-chair conformation, while the pyrrolidine ring has an envelope conformation with the unsubstituted C atom as the flap. The dihedral angles between the two p-Cl-substituted benzene rings and the indole ring are 33.13 (14) and 54.11 (14)°. In the crystal, molecules form inversion dimers through pairs of N—H⋯O hydrogen bonds [graph set R 2 2(8)]. Aromatic C—H⋯O hydrogen bonds extend these dimers into a ribbon structure, enclosing R 2 2(14) ring motifs, along the a-axis direction.

Crystal Structures of Ethyl 4-(4-Florophenyl)-6-phenyl-2-substituted-3-pyridinecarboxylates

Three substituted pyridinecarboxylates were synthesized; (I) ethyl 2-bromo-4-4(fluorophenyl)-6-phenyl-3-pyridinecarboxylate, C20H15BrFNO2, (II) ethyl 4-(4-fluorophenyl)-2-(4-morpholinyl)-6-phenyl-3-pyridinecarboxylate, C24H23FN2O3, and (III) ethyl 4-(4-fluorophenyl)-6-phenyl-2-(1-piperidinyl)-3-pyridinecarboxylate, C25H25FN2O2. It was found that compound (I) belongs to the orthorhombic system with space group P212121, compound (II) to the monoclinic system with space group P21/c, and compound (III) to the monoclinic system with space group C2/c. The morpholine ring in (II) and piperidine ring in (III) have the shape of the distorted chair configuration.

STRUCTURAL CHARACTERIZATION OF SUBSTITUTED CALCIUM TITANATE COMPOUNDS Ca1-xLaxTi1-xFexO3

The title compounds Ca1-xLaxTi1-xFexO3 (0.0 ≤ x ≤ 0.5) were prepared by solid state reaction at 1350°C for 24 hours. X-ray powder diffraction measurements were performed by step scanning mode.All the prepared samples were single phase of perovskite orthorhombic system and belong to the space group Pbnm. The crystal structure has been refined by Rietveld method using FULLPROF program. The exact coordinates of atoms, the unit cell dimension, isotropic temperature factors and the profile width parameters as well as the interatomic distances have been refined. It was found, that the unit cell parameters are related to the ideal perovskite cubic system and vary linearly with the cation substitution. The calculated values of the tolerance factor (t) for these compositions indicate a significant degree of distortion in the perovskite structure. The distortion decreases with increasing the substitution and maximum distortion corresponds to CaTiO3, which is consistent with the experimental results of cell distortion factor. Also, from the refined values of the crystallite size, it was found that the crystallite size increases with increasing the substituted cations.