Two Crystal Structures Towards the Discotic Columnar Mesophase of (1,4,8,11,15,18,22,25-Octahexylphthalocyaninato)nickel

1997 ◽  
Vol 53 (2) ◽  
pp. 231-240 ◽  
Author(s):  
M. Helliwell ◽  
A. Deacon ◽  
K. J. Moon ◽  
A. K. Powell ◽  
M. J. Cook
Keyword(s):  
Synchrotron Radiation ◽  
Conformational Changes ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
Area Detector ◽  
Ccd Detector ◽  
Slight Movement ◽  
Image Plate System

(1,4,8,11,15,18,22,25-Octahexylphthalocyaninato)nickel is a thermotropic liquid crystal, undergoing a transition to a discotic columnar mesophase at 418 K. Its crystals are weakly diffracting needles. Single-crystal X-ray diffraction studies at 103 K, using intense synchrotron radiation of wavelength 0.504 Å at Station F2, CHESS and the `Princeton 1k' CCD area detector, and at 295 K using a Cu Kα rotating anode diffractometer, have respectively shown that the symmetry of the crystals is increased from primitive monoclinic (space group P21/n) to C-centred monoclinic (space group C2/c) when the temperature is raised. Solution of the structure at each temperature shows that the increase in symmetry at 295 K arises from slight movement of the molecules, as well as increased thermal motion of the hexyl groups, and small conformational changes in these groups, indicating the first stage of the transition to the discotic columnar mesophase, when the hexyl groups are thought to become completely mobile. The quality of the refinement of the structure is indicative of what can now be realized by employing multipole wiggler synchrotron radiation and a CCD area detector, as well as cryocooling, for difficult small molecule samples. The temperature of the space group transition was determined at the Daresbury SRS, on Station 7.2, using a CCD detector to monitor an area of the diffraction pattern, whilst varying the temperature systematically. A gradual appearance of spots for h + k = 2n + l occurred between 205 and 195 K. Tests were also made using an image plate system at 195 and 293 K, which confirmed the transition from primitive to C-centred lattice symmetry with temperature. No other changes were apparent on the CCD or IP detectors.

scholarly journals Indole alkaloids from Vinca erecta type of sarpagine and ajmaline

2019 ◽  
Vol 10 (4) ◽  
pp. 409-416 ◽  
Author(s):  
Shahobiddin Adizov ◽  
Bakhodir Tashkhodjaev
Keyword(s):  
Conformational Changes ◽  
Absolute Configuration ◽  
Indole Alkaloids ◽  
Diffraction Method ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The single crystal X-ray diffraction method established the absolute configuration of the Vinca erecta indole alkaloids of the akuammidine sarpagine type (3S, 5S, 15R, 16R) and its o-acyl derivative, as well as the type of ajmaline, quebrachidine (2S, 3S, 5S, 7R, 15S, 16R, 17S) and majoridine (2R, 3S, 5S, 7R, 15R, 16S, 17R). Crystal data for C21H24N2O3 (1): orthorhombic, space group P212121 (no. 19), a = 6.3949(5) Å, b = 13.5009(10) Å, c = 22.461(3) Å, Z = 4, 7694 reflections measured (7.64° ≤ 2Θ ≤ 152.294°), 3813 unique (Rint = 0.0798) which were used in all calculations. The final R1 was 0.0680 (I > 2σ(I)) and wR2 was 0.1650 (all data). Crystal data for C23H26N2O4 (2): orthorhombic, space group P212121 (no. 19), a = 9.9730(13) Å, b = 10.2090(10) Å, c = 20.409(3) Å, Z = 4, 7959 reflections measured (8.666° ≤ 2Θ ≤ 151.998°), 4212 unique (Rint = 0.0386) which were used in all calculations. The final R1 was 0.0477 (I > 2σ(I)) and wR2 was 0.1171 (all data). Crystal data for C42H48N4O6 (3): monoclinic, space group P21 (no. 4), a = 8.9320(10) Å, b = 21.515(5) Å, c = 9.5420(10) Å, β = 97.103(10)°, Z = 2, 16677 reflections measured (9.34° ≤ 2Θ ≤ 151.836°), 7393 unique (Rint = 0.0278) which were used in all calculations. The final R1 was 0.0366 (I > 2σ(I)) and wR2 was 0.1037 (all data). Crystal data for C23H28N2O3 (4): orthorhombic, space group P212121 (no. 19), a = 10.636(2) Å, b = 11.208(12) Å, c = 16.725(13) Å, Z = 4, 1650 reflections measured (9.498° ≤ 2Θ ≤ 119.97°), 1650 unique (Rint = 0.0436) which were used in all calculations. The final R1 was 0.0608 (I > 2σ(I)) and wR2 was 0.1720 (all data). In alkaloids such as sarpagine and ajmaline exo, the substituents of alkaloids do not lead to conformational changes of a stable polycyclic framework. In the series of sarpagine, alkaloids form mono-salts in the tetrahedral nitrogen N4, and in indolines of the ajmaline type, the tetrahedral hybridization of the N1 and N4 atoms favors the formation of disols. In V. erecta alkaloids, the exomethylene fragment (C18-C19=C20-C21) of the polycyclic backbone always takes on the E-state.

Powder X-ray diffraction of azelastine hydrochloride, C22H25ClN3O·Cl

2020 ◽  
pp. 1-2
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
Lattice Parameters ◽  
Powder Pattern ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Space Group ◽  
X Ray

Commercial azelastine hydrochloride crystallizes in the monoclinic space group P21/n (#14) with a = 13.7844(5), b = 16.39920(14), c = 9.41231(22) Å, β = 97.5340(20)°, V = 2109.32(4) Å3, and Z = 4. The lattice parameters differ by −0.02, +0.04, and +0.04% from those in the previous determination (reflecting differences in the temperature and the sample source), and are more precise, from the use of synchrotron radiation. The experimental powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-070-1219.

The Structures of Imidazenil and Iodoimidazenil

2002 ◽  
Vol 55 (11) ◽  
pp. 737 ◽  
Author(s):  
Trevor W. Hambley ◽  
Andrew Katsifis ◽  
Robert B. Knott ◽  
Filomena Mattner ◽  
Branko Dikic
Keyword(s):  
Conformational Changes ◽  
Single Photon ◽  
Benzodiazepine Receptors ◽  
Photon Emission ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
Iodine 123

The iodinated analogue of imidazobenzodiazepine, imidazenil (1), has been prepared with the aim of radiolabelling it with iodine-123 and including it in a study to determine the role of benzodiazepine receptors in neurodegenerative diseases using single photon emission computer tomography (SPECT) imaging. A comparison of the bromo- and iodo-derivatives, as well as the conformational changes resulting from bromine–iodine substitution are described, and it is concluded that the substitution has no clear effect on the geometry. Crystal structures of (1) and iodoimidazenil (2) have been determined by X-ray diffraction methods and refined to R values of 0.059 (3817 F) and 0.048 (1318 F), respectively. The crystals of imidazenil are triclinic, space group P1–,a 12.537(4), b 18.211(6), c 7.852(2) Å, α 91.07(2), β 106.26(2), γ 77.86(2)�, Z 4, and those of iodoimidazenil are monoclinic, space group P21/a, a 12.185(2), b 7.558(2), c 18.287(2) Å, β 95.23(1)�, Z 4.

New mixed-valent alkali chain sulfido ferrates A1+x[FeS2] (A = K, Rb, Cs; x = 0.333–0.787)

2020 ◽  
Vol 235 (8-9) ◽  
pp. 275-290
Author(s):  
Michael Schwarz ◽  
Pirmin Stüble ◽  
Katharina Köhler ◽  
Caroline Röhr
Keyword(s):  
Alkali Metal ◽  
General Structure ◽  
Variable Number ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Modulated Structure ◽  
Space Group ◽  
X Ray ◽  
Local Coordination ◽  
Natural Pyrite

AbstractFour new mixed-valent chain alkali metal (A) sulfido ferrates of the general structure family ${A}_{1+x}\left[{\text{Fe}}_{x}^{\text{II}}{\text{Fe}}_{1-x}^{\text{III}}{\text{S}}_{2}\right]$ were synthesized in the form of tiny green-metallic needles from nearly stoichiometric melts reacting elemental potassium with natural pyrite (A = K) or previously prepared Rb2S/Cs2S2 with elemental iron and sulfur (A = Rb/Cs). The crystal structures of the compounds were determined by means of single crystal X-ray diffraction: In the (3+1)D modulated structure of K7.15[FeS2]4 (space group Ccce(00σ3)0s0, a = 1363.87(5), b = 2487.23(13), c = 583.47(3) pm, q = 0,0,0.444, R1 = 0.055/0.148, x = 0.787), a position modulation of the two crystallographically different undulated ${}_{\infty }{}^{1}\left[{\text{FeS}}_{4/2}\right]$ tetrahedra chains and the surrounding K cations is associated with an occupation modulation of one of the three potassium sites. In the case of the new monoclinic rubidium ferrate Rb4[FeS2]3 (x = $\frac{1}{3}$; space group P21/c, a = 1640.49(12), b = 1191.94(9), c = 743.33(6) pm, β = 94.759(4)°, Z = 4, R1 = 0.1184) the undulation of the tetrahedra chain is commensurate, the repetition unit consists of six tetrahedra. In the second new Rb ferrate, Rb7[FeS2]5 (x = 0.4; monoclinic, space group C2/c, K7[FeS2]5-type; a = 2833.9(2), b = 1197.36(9), c = 744.63(6) pm, β = 103.233(4)°, Z = 4, R1 = 0.1474) and its isotypic mixed Rb/Cs-analog Rb3.6Cs3.4[FeS2]5 (a = 2843.57(5), b = 1226.47(2), c = 759.890(10) pm, β = 103.7170(9)°, R1 = 0.0376) the chain buckling leads to a further increased repetition unit of 10 tetrahedra. For all mixed-valent ferrates, the Fe–S bond lengths continuously increase with the amount (x) of Fe(II). The buckling of the chains is controlled through the local coordination of the S atoms by the variable number of A cations of different sizes.

Strukturuntersuchungen an Diaryldichalkogeniden: Die Molekülstrukturen von [2,4,6-(CF3)3C6H2S]2,[2,4,6-Me3C6H2Te]2 und [2-Me2N-4,6-(CF3)2C6H2Te]2 / Structural Investigations of Diaryl Dichalcogenides: The Molecular Structures of [2,4,6-(CF3)3C6H2S]2, [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2

1992 ◽  
Vol 47 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Anja Edelmann ◽  
Sally Brooker ◽  
Norbert Bertel ◽  
Mathias Noltemeyer ◽  
Herbert W. Roesky ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Structural Investigations ◽  
Space Group ◽  
X Ray

Abstract The Molecular Structures of [2,4,6-(CF3)3C6H2S]2 (1) [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2 (3) have been determined by X-ray diffraction. Crystal data: 1: orthorhombic, space group P212121, Z = 4, a = 822.3(2), b = 1029.2(2), c = 2526.6(5) pm (2343 observed independent reflexions, R = 0.042); 2: orthorhombic, space group Iba 2, Z = 8, a = 1546.5(2), b = 1578.4(2), c = 1483.9(1) pm (2051 observed independent reflexions, R = 0.030); 3: monoclinic, space group P 21/c, Z = 4, a = 1118.7(1), b = 1536.5(2), c = 1492.6(2) pm, β = 98.97(1)° (3033 observed independent reflexions, R = 0.025).

A simple approach to determine the polarization coefficient at synchrotron radiation stations

2014 ◽  
Vol 47 (4) ◽  
pp. 1449-1451 ◽  
Author(s):  
Sergei Sulyanov ◽  
Pavel Dorovatovskii ◽  
Hans Boysen
Keyword(s):  
Synchrotron Radiation ◽  
Simple Procedure ◽  
Glass Plate ◽  
Intensity Variation ◽  
Incident Beam ◽  
Azimuth Angle ◽  
Area Detector ◽  
Ccd Detector ◽  
Diffraction Angle ◽  
Polarization Coefficient

A simple procedure for the measurement of the degree of linear polarization at a synchrotron radiation station is described. The diffraction pattern from a glass plate set perpendicular to the incident beam is registered using a two-dimensional area detector. The intensity variation along the azimuth angle ρ at a constant diffraction angle is fitted to the theoretical cos2ρ dependence. The results of measurements performed at a synchrotron radiation station with a CCD detector on the beam from a bending magnet are presented.

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

Silver(I)-Saccharinato Complexes with 2-(Aminomethyl)pyridine and 2-(2-Aminoethyl)pyridine Ligands: [Ag(sac)(ampy)] and [Ag2(sac)2(μ-aepy)2]

2005 ◽  
Vol 60 (9) ◽  
pp. 978-983 ◽  
Author(s):  
Sevim Hamamci ◽  
Veysel T. Yilmaz ◽  
William T. A. Harrison
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bonds ◽  
Monoclinic Space Group ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Pyridine Ligands

Two new saccharinato-silver(I) (sac) complexes, [Ag(sac)(ampy)] (1), and [Ag2(sac)2(μ-aepy)2] (2), [ampy = 2-(aminomethyl)pyridine, aepy = 2-(2-aminoethyl)pyridine], have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̄, respectively. The silver(I) ions in both complexes 1 and 2 exhibit a distorted T-shaped AgN3 coordination geometry. 1 consists of individual molecules connected into chains by N-H···O hydrogen bonds. There are two crystallographically distinct dimers in the unit cell of 2 and in each dimer, the aepy ligands act as a bridge between two silver(I) centers, resulting in short argentophilic contacts [Ag1···Ag1 = 3.0199(4) Å and Ag2···Ag2 = 2.9894(4) Å ]. Symmetry equivalent dimers of 2 are connected by N-H···O hydrogen bonds into chains, which are further linked by aromatic π(py)···π(py) stacking interactions into sheets.

The Dichloroplatinum(II) and Dichloropalladium(II) Complexes of 1,4-Diazacycloheptane: Preparative, Structural and Conformational Studies

1996 ◽  
Vol 49 (12) ◽  
pp. 1301 ◽  
Author(s):  
GW Allen ◽  
ECH Ling ◽  
LV Krippner ◽  
TW Hambley
Keyword(s):  
Crystal Structures ◽  
Chelate Ring ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Membered Chelate Ring ◽  
Alternative Conformation

The preparation and purification of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] ( hpip = homopiperazine = 1,4-diazacycloheptane) are described. Crystal structures of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] have been determined by X-ray diffraction methods and refined to R values of 0.023 (932 F) and 0.023 (948 F). The crystals of [Pt( hpip )Cl2] are orthorhombic, space group Pbcm , a 7.7019(8), b 9.8080(12), c 12.1944(14) Ǻ, and those of [Pd( hpip )Cl2] are monoclinic, space group P21/m, a 6.1001(9), b 11.527(2), c 6.458(I) Ǻ, β 106.30(2)°. The seven- membered rings of the ligands in both complexes adopt boat-like conformations in which the five- membered chelate ring has an eclipsed N-C-C-N group and the six- membered chelate ring adopts a chair conformation. Molecular mechanics methods were used to investigate whether this conformation was a crystallographic artefact but it was found to be real. An alternative conformation in which the six-membered chelate ring adopts a skew-boat conformation was also investigated. It was found to be less stable than the conformation observed in the crystal structures, but to a degree that depends on whether non-bonded interactions involving the metal atom were included or not.

Darstellung von Mononitropentahydrohexaborat(2-) und Kristallstruktur von M2[B6H5(NO2)], M = K, Cs / Preparation of Mononitropentahydrohexaborate(2—) and Crystal Structure of M2[B6H5(NO2)], M = K, Cs

1993 ◽  
Vol 48 (12) ◽  
pp. 1727-1731 ◽  
Author(s):  
A. Franken ◽  
W. Preetz ◽  
M. Rath ◽  
K.-F. Hesse
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Dichloromethane Solution ◽  
Space Group ◽  
X Ray ◽  
Diethylaminoethyl Cellulose

By electrochemical oxidation of [B6H6]2- in the presence of nitrite ions and the base DBU in dichloromethane solution mononitropentahydrohexaborate [B6H5(NO2)]2- ions are formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of the K and Cs salt were determined from single crystal X-ray diffraction analyses. K2[B6H5(NO2)] is monoclinic, space group P21/m with a = 5.953(1), b = 8.059(4), c = 8.906(1) Å, β = 109.553(9)°; Cs2[B6H5(NO2)] is monoclinic, space group P21/a with a = 9.438(6), b = 9.644(7), c = 11.138(9) Å, β = 101.44(9)°. The B6 octahedron is compressed in the direction of the B—NO2 bond by about 5%, with bond lengths between 1.67 and 1.77 A.

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