Crystallographic and spectroscopic study of 4,4′-diaminobenzophenone

4,4-Diaminobenzophenone crystallizes in the trigonal space groupP3₁:a = 9.136(2),c = 10.953(3) Å,Z = 3. The structure has been determined by direct methods (MULTAN) from MoK diffractometer data and refined by full-matrix least squares toR = 0.044 for 2177 reflections. Phosphorescence emission and optically detected magnetic resonance spectra of 4,4-diaminobenzophenone and those of some structurally related benzophenones are discussed.     

Crystallographic and spectroscopic study on 4,4′-diiodobenzophenone

4,4-Diiodobenzophenone crystallizes in the orthorhombic space groupCcc 2:a = 28.079,b = 7.413,c = 6.050Å,Z = 4. The structure has been determined by a combination of Patterson and direct methods with MoK diffractometer data and refined by full-matrix least squares toR = 0.047 for 1512 reflections. The molecule possesses Crystallographic two-fold symmetry. The phosphorescence emission spectra of 4,4-diiodobenzophenone are discussed in the light of structural data and spectroscopic data of several related benzophenones.Extensive use has been made of the Cambridge Crystallographic Data File, Crystallographic Data Centre, University Chemical Laboratory, Lenafield Road, Cambridge, England.     

Crystallographic Characterization of Dipyridylamine Derivatives

Abstract  

Dipyridylamine has been coupled with phenyl groups to yield new organic ligands. During the course of one reaction a lithium salt of dipyridylamine was isolated as the product. These new compounds were characterized by single crystal X-ray diffraction, which reveals that π–π stacking interactions as well as hydrogen bonding permeate the isolated compounds in the solid state. BrPhDPA, compound 1, crystallizes in the monoclinic P2₁ space group with cell parameters a = 5.8291(1), b = 8.8504(2), c = 13.2341(3) ? and β = 91.928(1)°. 3-ThPh(DPA)₂, compound 4, crystallizes in the orthorhombic C2/c space group with cell parameters a = 14.8033(7), b = 11.4124(4), c = 16.11780(7) ? and β = 115.911(3)°. Finally the lithium salt, [Li(HDPA)(H₂O)₂](H₂DPA)(Cl)₂(H₂O), compound 5, crystallizes in the monoclinic Cmcm space group with cell parameters a = 14.043(3), b = 12.370(3) and c = 13.389(3) ?.     

Crystallographic table of chemical elements

Regularities of changes in the structure of chemical elements in crystalline and liquid states under the action of temperature and pressure are systematized on the basis of the periodic table.     

Crystallographic investigations of benzothiazol-2-yl-hydrazine

The title compound crystallizes in the monoclinic space group P2₁/n with unit cell parameters a = 10.842(9), b = 5.750(7), c = 12.964(6) Å, = 110.13(6), V = 758.8(11) ų and Z = 4. The final reliability index is 0.060 for 1034 observed reflections. The five-membered heterocyclic thiazole ring is coplanar with its fused benzene ring. The crystal structure is stabilized by two intermolecular N=H s N hydrogen bonded interactions.     

Minimal Cayley Graphs of Crystallographic Groups

Crystallography Reports - The Cayley graphs of crystallographic groups $$G_{p}^{p}$$, constructed on the minimal number of generators, are discussed. Some theorems on the existence of minimal nets,...     

Crystallographic and IR spectral study ofcis-bis(creatinine-N)dinitro platinum(II)

Acis-Pt(creat)₂(NO₂)₂ complex was synthesized stereoselectively in a high yield (65%) and characterized by IR spectral and X-ray diffraction analysis. Crystal data: Pt(C₄H₇N₃O)₂(NO₂)₂,M _r=767.55, monoclinic, space groupP2₁/n,a=9.736(1),b=13.433(1),c=12.098(1) Å,=110.55(1)°,V _c=1482(1) ų,Z=2,D _x=3.441 g cm^–3,(MoK)=0.71073 Å,=97.0 cm^–1,F(000)=1504,T=292 K,R=0.026 andR _w=0.028 for 2061 observed reflections with I>2(I). The structure consists of Pt(creat)₂(NO₂)₂ molecules disposed in general positions and joined by N-HO and N-HN hydrogen bonds. The platinum atom has square-planar PtN₄ coordination of twocis disposed pairs of nitro [Pt-N_av 2.023(7) Å] and creatinine [Pt-N(endo)_av 1.991(8) Å] ligands. The creatinine moieties are planar and tilted to the equatorial plane by ~80°.     

Crystallographic nets and their quotient graphs

Crystallographic nets are defined. It is shown how these nets can be generated from finite graphs which are called the quotient graphs of the nets. The procedure yields the topology of the nets, their crystallographic point groups and their lattice types. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Future contributions toJournal of Crystallographic and Spectroscopic Research

Future contributions toJournal of Crystallographic and Spectroscopic Research     

Crystallographic Studies of Clathrate Hydrates. Part I

Low-temperature neutron and X-ray diffraction studies show the gas hydrates of oxygen and nitrogen to be structure II (Fd3m), as recently found also for the hydrates of the small argon and krypton molecules. New lattice parameters of three structure I and 14 structure II hydrates from powder X-ray diffraction at 170 K are reported. The thermal expansion coefficient of tetrahydrofuran hydrate was determined from X-ray diffraction at some 50 temperatures between 18 and 263 K and found to be three times as great as for ice near 100 K and 30% higher near 250 K. Lattice parameters qf 40 type II clathrate hydrates are compared at 0°C and found to lie within 0.10 Å of 17.30 Å.     

Future contributions toJournal of Crystallographic and Spectroscopic Research

Future contributions toJournal of Crystallographic and Spectroscopic Research     

Comparative Crystallographic and Hydrogen-bonding Analysis of Pregnane Derivatives

A crystallographic comparison comprised of some geometrical and structural features of a steroids series (pregnane derivatives) is made in the present paper. Some selected bond distances and bond angles of interest are discussed in detail. Conformations of individual ring systems in a series of 46 pregnane derivatives have been calculated and discussed. Correlation of ring conformations especially the rarer ones, vis-a-vis the multiple bonds and ring junctions has been discussed. Graphical presentations of ring conformations are made for all the five- and six-membered rings to show the relative frequency of their occurrence. 17β-side chain conformation is discussed in some pregn-20-one structures. X–H···A intra- and intermolecular interactions in the identified derivatives have been discussed with the standard distance and angle cut-off criteria. Distance-angle scatter plots for both kinds of interactions are presented for a better understanding of the packing interactions which exist in pregnane molecules.     

Future contributions toJournal of Crystallographic and Spectroscopic Research

Future contributions toJournal of Crystallographic and Spectroscopic Research     

Crystallographic defects in epitaxial layers of cadmium sulphide

Thin epitaxial films of CdS deposited in high vacuum on ionic single crystal substrates have been studied by transmission electron microscopy. The (100), (110) and (111) faces of NaCl and the (111) face of BaF₂ were used as substrate surfaces. Both cubic sphalerite and hexagonal wurtzite structure films have been produced. The orientations of the sphalerite structure films were (100) and (110) and were produced on substrate faces having the same two orientations. The wurtzite structure films were in (0001) orientation and grew on (111) oriented substrate faces. For a fixed rate of deposition both the number and type of defects found in the films appear to be dependent upon the growth temperature and the crystal structure. Annealing the films at a high temperature has been tested as a means for reducing their defect content and the effect is very different for the two crystal structures. A reduction in the defect content of the wurtzite structure films is induced but no change in the crystal structure occurs. In contrast to this, the sphalerite structure films undergo a progressive phase transformation to the wurtzite stucture while at the same time losing a high proportion of their defects.     

Crystallographic shear in niobium oxides of different compositions

Defect structures related to crystallographic displacement are revealed in niobium oxides of different composition (Nb₂O₅, NaNbO₃, and solid solutions based on NaNbO₃) by X-ray powder diffraction, X-ray fluorescence spectroscopy, and Raman scattering. It is suggested that lattice shear in NaNbO₃ and NaNbO₃ based solid solutions lead to the block structure of crystals. The effect of the thermodynamic history of objects under study on the formation of a defect structure of this type is demonstrated.