The methylgallium-2-carboxylatobenzimidazolato hexamer, [MeGa·C8H4N2O2]6·C6H6·(Me2C6H4)2; synthesis and X-ray crystal structure

1999 ◽  
Vol 77 (4) ◽  
pp. 434-438 ◽  
Author(s):  
Steven J Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Room Temperature ◽  
Direct Methods ◽  
Membered Ring ◽  
Coordination Geometry ◽  
Temperature Reaction ◽  
Full Matrix ◽  
X Ray ◽  
Solvent Molecules

The room-temperature reaction of Me3Ga with benzimidazole 2-carboxylic acid in xylene solvent has yielded a novel crystalline hexameric gallium compound with "MeGa" moieties bridged by the doubly depronotated ligand precursor. Crystals of [MeGa(4,5-benzimidazolato-2-carboxylato)]6·(C6H6)·(m-Me2C6H4)2 are monoclinic, a = 18.091(2), b = 17.094(2), c = 13.2215(5) Å, Z = 2, space group C2/m. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R (F, I [Formula: see text] 3σ(I)) = 0.064 (Rw (F2, all data) = 0.134). The hexameric Ga complex contains a six-membered ring of Ga atoms, bridged by the benzimidazolate ligands with the benzo rings projecting alternately above and below the Ga plane, thus forming a ball-shaped molecule. The complex could have ideal D3d symmetry, but it contains an encapsulated molecule of benzene, which distorts the regularity of the Ga6 hexagon, and reduces the symmetry of the complex to the crystallographically observed C2h. The coordination geometry at each of the two independent GaO2N2C centres approximates a trigonal bipyramid, with a N2C trigonal plane, and the O atoms above and below; average dimensions are Ga-O = 2.176(2), Ga-N = 1.973(3), Ga-C = 1.927(5) Å, O-Ga-O = 165°. The unit cell also contains four m-xylene solvent molecules (outside the molecular cage).Key words: gallium, crystal structure, benzene intercalate, benzimidazolecarboxylic acid.

Structural Systematics of Rare Earth Complexes. VII. Crystal Structure of Bis(2,2'/6',2␛-Terpyridinium) Octaaquaterbium(III) Heptachloride Hydrate

1994 ◽  
Vol 47 (2) ◽  
pp. 391 ◽  
Author(s):  
CJ Kepert ◽  
BW Skeleton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Structural Characterization ◽  
Title Compound ◽  
Room Temperature ◽  
Chloride Ions ◽  
Full Matrix ◽  
X Ray

The room-temperature single-crystal X-ray structural characterization of the title compound (tpyH2)2[Tb(OH2)8]Cl7.~2⅓H2O is recorded. Crystals are triclinic, Pī , a 17.063(5), b 16.243(3), c 7.878(3) Ǻ, α 84.78(2), β 84.39(3), γ 87.81(2)°, Z = 2 formula units; 3167 'observed' diffractometer reflections were refined by full-matrix least-squares procedures to a residual of 0.057. Notable features of interest of the compound are the 'chelation' of chloride ions by the terpyridinium cations , and the existence of a free [Tb(OH2)8]2+ cation in the presence of an abundance of chloride ions.

The Crystal Structure of benzoyl – histidine monohydrate

1994 ◽  
Vol 209 (10) ◽  
Author(s):  
R. Fröhlich ◽  
R. K. Arni ◽  
A. Bozopoulos ◽  
C. A. Kavounis
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Tautomeric Form ◽  
Direct Methods ◽  
Membered Ring ◽  
Hydrogen Bridge ◽  
Reliability Factor ◽  
Full Matrix ◽  
Benzoyl Group ◽  
Expected Values

AbstractThe crystal structure of benzoyl-histidine monohydrate (BYLH hereafter), CThe structure was solved with direct methods. All positional and anisotropic thermal parameters were refined by full-matrix least-squares calculations. The final reliability factor wasThe compound consists of a histidine molecule bound to a benzoyl group. There is also a cocrystallized water molecule stabilized through a hydrogen bridge.The 5-membered ring of the histidine has its tautomeric form, after the transfer of the H atom from the NAll angle values and bond distances agree very well with the expected values in the literature.

Synthetic plant growth regulators. V. The synthesis and crystal structure of a hybrid gibberellin-helminthosporic acid

1980 ◽  
Vol 33 (5) ◽  
pp. 1061 ◽  
Author(s):  
JV Turner ◽  
BF Anderson ◽  
LN Mander
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Carboxylic Acid ◽  
Standard Procedure ◽  
Direct Methods ◽  
Detailed Comparison ◽  
Synthesis And Crystal Structure ◽  
Full Matrix ◽  
Cyclopropyl Ketone ◽  
R Value

(3aRS,4RS,6RS,8aSR)-5-Methyleneoctahydro-4H-3a,6-methanoazulene-4-carboxylic acid (7) has been synthesized and a detailed comparison made between its molecular structure and that of gibberellic acid (4). Indane-5-carboxylic acid (8) was converted by an alternating sequence of reduction and isomerization into the hydrindene acid (11). The diazomethyl ketone derived from (11) was transformed to cyclopropyl ketone (12) which was reduced by Li/NH3 with stereochemical inversion at the β-carbon to give a 1:3 mixture of ketones (13) and (14) respectively. Ketone (14) was then converted into the title acid (7) by a standard procedure. ��� Molecules of (7) crystallize in space group P2/c with a 7.782(1), b 11.055(1), c 14.559(3) Ǻ, β 116.05(1)°. The structure was solved by direct methods and refined by full-matrix least squares to a final R value of 0.053.

Preparation, properties, and X-ray crystal structure of a 1:1 complex of tetrathiafulvalene and p-dinitrobenzene

1982 ◽  
Vol 60 (16) ◽  
pp. 2057-2061 ◽  
Author(s):  
Martin R. Bryce ◽  
Anthony S. Secco ◽  
James Trotter ◽  
Larry Weiler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
Crystalline Complex ◽  
X Ray ◽  
Triclinic System ◽  
Donor Acceptor ◽  
Bulk Magnetic Susceptibility ◽  
R Value

A crystalline complex of tetrathiafulvalene and p-dinitrobenzene has been prepared and characterised by esr and ir spectroscopy, bulk magnetic susceptibility, dc conductivity, and an X-ray diffraction analysis. It is a neutral 1:1 complex which is an insulator at room temperature, σRT = 2.5 × 10−7 ohm−7 cm−1. The complex crystallizes in the triclinic system, space group [Formula: see text] with cell constants a = 6.915(1), b = 7.615(1), c = 8.149(1) Å, α = 79.39(1), β = 69.55(1), γ = 70.81(1)°, Z = 1. Data were collected on an Enraf-Nonius CAD-4 diffractometer. The structure was solved by direct methods and refined to an R-value of 0.028 for 1222 observed reflections. The structure consists of molecules stacked in an alternating donor–acceptor fashion along the c-axis. Mixed sheets parallel to [Formula: see text] are comprised of tetrathiafulvalene and p-dinitrobenzene molecules arranged end-on in the [021] direction.

Synthesis and Crystal and Molecular Structure of trans-Dichloro(ethanedial dioximato(1—)-N,N')(ethanedial dioxime-N,N')rhodium(III)

1989 ◽  
Vol 44 (1) ◽  
pp. 5-8
Author(s):  
Michel Mégnamisi-Bélombé
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Room Temperature ◽  
Crystal And Molecular Structure ◽  
Crystallographic Direction ◽  
Monoclinic Space Group ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cl Atoms

Abstract trans-Dichloro(ethanedial-dioximato)(ethanediaI-dioxime)rhodium (III), RhCl2(GH)(GH2), has been synthesized and its structure determined by single crystal X-ray diffraction at room temperature. C4H7Cl2N4O4Rh, Mr = 348.94. monoclinic space group P21/ɑ; a = 10.543(3), b = 8.363(2), c = 11.512(3)Å ; β = 92.79(2)°; V = 1024Å3; Z = 4; Dc = 2.26 Mg m-3. Final Rw = 0.075 for 2035 reflections and 139 parameters. The coordination geometry around Rh is a dis­torted (4+2) octahedron, with four chelating N atoms lying in the equatorial plane and the two Cl atoms in the apical positions. The H atoms of the oxime groups are involved in relatively weak intramolecular O-H-O bridgings, as well as in very strong intermolecular bridgings which extend throughout the crystal structure and propagate nearly parallel to the [101] crystallographic direction.

scholarly journals Synthesis, Characterization, and Crystal Structure of Negundoside (2′-p-Hydroxybenzoyl Mussaenosidic Acid)

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Suresh Sharma ◽  
B. D. Gupta ◽  
Rajni Kant ◽  
Vivek K. Gupta
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Method ◽  
Monoclinic Crystal System ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
Full Matrix ◽  
X Ray ◽  
Cell Parameters

The structure of title compound Negundoside (2′-p-hydroxybenzoyl mussaenosidic acid) was established by spectral and X-ray diffraction studies. The compound crystallizes in the monoclinic crystal system with space group P21 having unit cell parameters: a=11.6201 (5) Å, b=9.2500 (4) Å, c=12.2516 (5) Å, β=97.793 (4)°, and Z=2. The crystal structure was solved by direct method using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R value of 0.0520 for 3389 observed reflections.

Crystal structure of 17,18,19-trisnorstemodan-3,13-dione

1984 ◽  
Vol 62 (9) ◽  
pp. 1828-1830 ◽  
Author(s):  
Stephen V. Evans ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Membered Ring ◽  
Full Matrix ◽  
Bond Lengths ◽  
Compound C ◽  
Tetracyclic System ◽  
Atom Bond

Crystals of the title compound, C17H24O2, are monoclinic, P21/c, a = 10.395(2), b = 10.980(1), c = 13.181(3) Å, β = 113.55(1)°, Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0.051 for 1622 reflections with I ≥ 3σ(I). The molecule contains a tetracyclic system of three six-membered rings and one five-membered ring; the structure exhibits disorder of one C atom. Bond lengths and angles are normal.

Ring contraction of 4-substituted 2,6-dichlorophenols. The crystal structure of 2,2,4α,5α-Tetrachloro-1α,3α-dihydroxycyclopentane-1,4-carbolactone

1977 ◽  
Vol 30 (10) ◽  
pp. 2195 ◽  
Author(s):  
RM Christie ◽  
RW Rickards ◽  
KJ Schmalzl ◽  
D Taylor
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Major Product ◽  
X Ray Diffraction ◽  
Ring Contraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Counter Data

Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4α- alkyl-2,2,5α-trichloro-1α,3α-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4α,5α-tetrachloro-1α,3α-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) Ǻ, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/σ(I) ≥ 3.0).

Synthesis, characterization, and X-ray structural analysis of the Cu(I) derivative, [Me2Ga(OCH2CH2NMe2)N2C5H7]Cu• PPh3

1981 ◽  
Vol 59 (3) ◽  
pp. 518-523 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Structural Analysis ◽  
Copper Atom ◽  
Direct Methods ◽  
Carbonyl Complex ◽  
Coordination Geometry ◽  
Tetrahedral Coordination ◽  
Full Matrix ◽  
X Ray ◽  
Complex Crystals ◽  
Distorted Tetrahedral Coordination

The Cu(I) complex [Me2Ga(OCH2CH2NMe2)N2C5H7]Cu•PPh3 has been synthesized and its fluxional behavior in solution probed. Attempts have been made to isolate the analogous Cu(I) carbonyl complex. Crystals of [dimethyl(3,5-dimethyl-1-pyrazolyl)(N,N-dimethylethanolamino)gallato (N(2),O,N(3))](triphenylphosphine)copper(I) are monoclinic, a = 18.871(2), b = 9.464(1), c = 18.374(2) Ā, β = 109.62(1)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.028 and Rw = 0.035 for 2729 reflections with I ≥ 3σ(I). The copper atom is bonded to the phosphine and to the tridentate Me2Ga(OCH2CH2NMe2)N2C5H7− ligand resulting in a distorted tetrahedral coordination geometry. The Cu—P distance of 2.156(1) Å is unusually short. Other important bond distances (corrected for libration) are: Cu—O, 2.163(2), Cu—N(pyrazolyl), 2.025(3), Cu—N(amino), 2.144(3), Ga—O, 1.896(3), Ga—N, 2.005(3), and Ga—C, 1.972(5) and 1.987(5) Å.

Beiträge zur Strukturchemie phosphorhaltiger Ketten und Ringe, IX [1]. Die Molekül- und Kristallstruktur von Tri-tert-butylcyclotriphosphanpentacarbonyl- chrom(O), [(t-BuP)3Cr(CO)5] / Structural Chemistry of Phosphorus-Containing Chains and Rings, IX [1]. The Molecular and Crystal Structure of Tri-tert-butylcydotriphosphane-pentacarbonyl-chromium (0), [(t-BuP)3Cr(CO)5]

1984 ◽  
Vol 39 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Karl-Friedrich Tebbe ◽  
Magda Fehér
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Membered Ring ◽  
Free Molecule ◽  
Donor Ligand ◽  
Space Group ◽  
X Ray ◽  
Phosphorus Containing

The structure of [(t-BuP)3Cr(CO)5], C17CrH27O5P3, has been determined by single crystal X-ray techniques, solved by ‘direct methods', and refined to R = 0.048, wR = 0.050 for 3657 reflections by blocked least squares. The compound crystallizes in the space group P 21/c with a = 1664.9 pm, b = 916.5 pm , c = 3089.8 pm, β= 91.45° and Z = 8 formula units. The structure consists of two crystallographically independent but structurally nearly identical mononuclear [(t-BuP)3Cr(CO)5] complexes with the three-membered ring (t-BuP)3 as an unidentate σ-donor ligand. Compared to the free molecule (t-BuP)3 the cyclophosphane ligand is slightly distorted on account of its coordination to the Cr(CO)5-group.

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