5-Hydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one (Tectochrysin) and 2,5-Dihydroxy-7-methoxy-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one: Isolation From Uvaria rufas and X-Ray Structures

1989 ◽  
Vol 42 (12) ◽  
pp. 2289 ◽  
Author(s):  
K Chantrapromma ◽  
C Pakawatchai ◽  
BW Skelton ◽  
AH White ◽  
S Worapatamasri
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray

5-Hydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one ( tectochrysin ) (1), 5-hydroxy-7,8-di-methoxy-2-phenyl-4H-1-benzopyran-4-one (7-0-methylwogonin) (2), 5-hydroxy-6,7-dimethoxy-2-phenyl-4H-1-benzopyran-4-one (6,7-O,O-dimethylbacaiein) (3) and 2,5-dihydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one (4) have been isolated from the roots of Uvaria rufas Blume. The crystal structures of (1) and (4) have been determined by X-ray diffraction methods from diffractometer data at 295 K and refined by full matrix least squares. Crystals of (1) are monoclinic P21/c, a 10.l28(3), b 15.289(5), c 8.215(4) �,β 92.39(3)� Z 4; R 0.045 for No 874 'observed' reflections; crystals of (4) are monoclinic P21/c, a 12.299(4), b 6.489(3), c 16.579(6) �, β 90.24(3)� Z 4; R 0.051 for No 1016.

A REFINEMENT OF THE CRYSTAL STRUCTURES OF (NH4)2TeBr6 AND Cs2TeBr6

1966 ◽  
Vol 44 (8) ◽  
pp. 939-943 ◽  
Author(s):  
A. K. Das ◽  
I. D. Brown
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Bromine Atom ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Anisotropic Temperature ◽  
Temperature Factors

(NH4)2TeBr6 and Cs2TeBr6 crystals have the cubic K2PtCl6 structure with space group: [Formula: see text] with a0 = 10.728 ± 0.003 Å and 10.918 ± 0.002 Å respectively. The positional coordinate of the bromine atom, and the anisotropic temperature factors of all atoms in the unit cell, have been refined for both crystals by a full matrix least-squares analysis of the three dimensional X-ray diffraction data (R = 0.08). The Te—Br distance, corrected for probable thermal motions of atoms forming the bond, is 2.70 ± 0.01 Å in both crystals.

The Flavonoids of Combretum quadrangulare: Crystal structures of the Polymorphic Forms of 5-Hydroxy-2-(4'-hydroxy-3',5'-dimethoxyphenyl)-3,7-dimethoxy-4H-1-benzopyran-4-one

1985 ◽  
Vol 38 (8) ◽  
pp. 1177 ◽  
Author(s):  
IR Castleden ◽  
SR Hall ◽  
S Nimgirawath ◽  
S Thadaniti ◽  
AH White
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Polymorphic Forms

The following substituted 2-phenyl-4H-1-benzopyran-4-ones have been isolated from the dried flowers of Combretum quadrangulare Kurz ( Combretaceae ): 5-hydroxy-3,3′,4′,5′,7-pentamethoxy ( combretol ) (1), 3′,5-dihydroxy-3,4′,7-trimethoxy ( ayanin ) (2) and 4′,5-dihydroxy- 3,3′,5′,7-tetramethoxy (3). The last substance (3) was obtained as a mixture of two polymorphic forms (α and β) each of which was characterized by X-ray diffraction. Diffractometer data at 295 K were refined by full matrix least squares to residuals of 0.043 (1181 'observed' reflections) for the α-phase and 0.044 (1421) for the β phase of (3). Crystals of the α-phase of (3) are triclinic, Pī, a 12.663(6), b 9.592(4), c 7.444(4) Ǻ, α 102.48(3), β 101.39(4), γ 91.72(4)°,Z 2. Crystals of the β-phase of (3) are monoclinic P21/n, a 17.139(8), b 12.728(6), c 7.845(7) Ǻ, β 95.07(6)°, Z 4. An unambiguous synthesis of (3) was also achieved.

scholarly journals Crystal structure of Tetraaqua(ethylenediamine)nickel(II) sulfate dihydrate and of Tetraaqua(2,2'-bipyridyl)nickel(II) sulfate dihydrate

1984 ◽  
Vol 37 (5) ◽  
pp. 921 ◽  
Author(s):  
PC Healy ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Oxygen Atoms

The crystal structures of the title compounds, [Ni(OH2)4(en)] [SO4].2H2O, (1), and [Ni(OH2)4(bpy)]- [SO4].2H2O, (2), have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by full matrix least-squares methods to residuals of 0.028,0.031 for 1852, 4323 independent 'observed' reflections respectively. Crystals of (1) are monoclinic, C2/c, a 9.459(4), b 12.192(7), c 12.294(3) �, β 119.84(4)�, Z 4. In the cation, Ni-N is 2.061(2) �; Ni-O (trans to O, N respectively) are 2.106(2), 2.063(2) �. Instead of being enlarged above 90� as predicted from repulsion theory, the angle between the pair of oxygen atoms trans to nitrogen is diminished, being 87 14(7)�. Crystals of (2) are triclinic, P1, a 11.476(5), b 9.351(5), c 7.793(4) �, α 77.63(4), β 83.52(3), γ87.40(4)�, Z 2. In the cation, Ni-N are both 2.063(2) �. Ni-O (trans to N, O respectively) are 2.060(2), 2.O42(2); 2.O80(2), 2�. The short Ni-O distance [2.042(2)�] is associated with the coordination of a trigonal water molecule.

The Crystal-Structures of (±)-(E)-2-(1-Amino-Ethylidene)-4,4,6-Trimethylcyclohexane-1,3-Dione [(±)-Aminoangustione] and (E)-2-(1-Aminoethylidene)-4,6,6-Trimethylcyclohex-4-Ene-1,3-Dione (Aminodehydroangustione)

1986 ◽  
Vol 39 (6) ◽  
pp. 923 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
AH White
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray

The crystal structures of (�)-(E)-2-(1-aminoethylidene)-4,4,6- trimethylcyclohexane-1,3-dione [(�)- aminoangustione ] (8) and (E)-2-(1- aminoethylidene )-4,6,6-trimethylcyclohex-4-ene-1,3-dione ( aminodehydroangustione ) (9) have been determined by X-ray diffraction. Diffractometer data at 295 K were refined by full-matrix least-squares to residuals of 0.057 (712 'observed' reflections) for (8) and 0.061 (571) for (9). Crystals of (8) are tetragonal I 41/a, a 21.68(1), c 9.426(6)Ǻ, Z 16; crystals of (9) are orthorhombic Pmab , a 7.077(2), b 11.421(6), c 13.283(4)Ǻ, Z 4.

Crystal structures of trans-Dichloro- and Dibromo-bis(2,6-dimethylpyridine)copper(II)

1977 ◽  
Vol 30 (9) ◽  
pp. 1947 ◽  
Author(s):  
JA Campbell ◽  
CL Raston ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Compound A ◽  
Full Matrix ◽  
X Ray ◽  
Square Planar

The crystal structures of the title compounds have been determined at 295(1) K by X-ray diffraction and refined by full-matrix least squares to residuals of 0.045 and 0.067 for 1224 and 1955 ?observed? reflections respectively. The compounds are isomorphous (triclinic, Pī, Z 1). Dichloro compound: a 8.068(2), b 8.024(2), c 7.646(2) Ǻ, α 93.84(2), β 113.44(2), γ 117.11(2)�. Dibromo compound: a 7.999(2), b 7.921(2), c 7.849(2) Ǻ, α 94.37(2), β 112.85(2), γ 115.99(2)�. The copper atoms are square-planar coordinated with two halide and two base ligands coordinated necessarily trans by virtue of the siting of the molecule on a centre of symmetry. Cu-X, Cu-N are 2.264(2), 2.011(3) (dichloro); 2.425(1), 1.997(4) Ǻ (dibromo). The plane of the lutidine is almost normal to the CuN2X2 plane.

Crystal structures of o-phenylenediarsine oxychloride (a redetermination) and o-phenylenediarsine oxybromide

1975 ◽  
Vol 28 (1) ◽  
pp. 15 ◽  
Author(s):  
JC Dewan ◽  
K Henrick ◽  
AH White ◽  
SB Wild
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Limits Of Error

The crystal structures of the title compounds have been established by X-ray diffraction at 295 K, being refined by full-matrix least-squares to residuals of 0.054 (0.051) respectively 2715 (469) reflections with I > σ(I)]. Crystals are monoclinic, space group C2/c, the compounds being isomorphous. Oxychloride: a = 14.534(4), b = 8.337(2), c = 7.653(1)Ǻ, β = 106.48(1)�. Oxybromide: a = 14.884(4), b = 8.360(2), c = 7.726(1)Ǻ, β = 105.30(1)�, Z = 4. With the exception-of the arsenic- halogen distance, the geometries of the two molecules are identical within the limits of error: for the oxychloride As-O-As, 121.8(3); Cl- As-O,98.03(6); Cl-As-C, 97.2(2); O-As-C, 92. 9(2)� ; As-O, 1.787(3); As-C, 1.941(5) Ǻ. As-Cl is 2.222(2) and As-Br 2.381(2) Ǻ.

Crystal structures of N,N,N',N'-Tetramethylthiuram monosulphide and Diiodo(N,N,N',N'-tetramethylthiuram monosulphide)mercury(II)

1977 ◽  
Vol 30 (8) ◽  
pp. 1693 ◽  
Author(s):  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
Metal Atom ◽  
X Ray Diffraction ◽  
Sulphur Atom ◽  
Full Matrix ◽  
X Ray ◽  
The Common ◽  
Trigonal Prismatic

The crystal structures of the title compounds, Me2NC(S)SC(S)NMe2 (tmtm) and I2Hg(tmtm), have been determined by single-crystal X-ray diffraction at 295 K and refined by full-matrix least squares to residuals of 0.038 and 0.050 respectively for 1080 and 1532 ?observed? reflections. ��� The ligand tmtm is monoclinic, P21/a, a 14.096(4), b 7.457(3), c 10.178(3)Ǻ, β 110.55(3)�, Z4. The complex I2Hg(tmtm) is orthorhombic, P212121, a 12.910(3), b 12.441(3), c 9.863(2) Ǻ, Z4. ��� The structure of the ligand comprises a pair of planar Me2NCS2 fragments linked at the common central sulphur atom with a dihedral of 78.4�. As in the related tetraethylthiuram disulphide, the ?CS2- geometry is very asymmetric: <C=S> 1.657; <C-S> 1.793 Ǻ; <S-C-S> 119.3; <S-C-N> 115.2; <S=C-N> 125.4�; with C-S-C, 103.2(2)�. The metal-atom geometry in I2Hg(tmtm) is pseudo-trigonal prismatic, as in I2Hg(Me2NCS2- S2CNMe2), the prism apex being occupied by a ligand sulphur atom, but considerable changes are observed in the geometry about the metal as a consequence of the change in the ligand ?bite?.

Lewis-Base Adducts of Group-11 Metal(I) Compounds. XXIX. Crystal Structures of Bis(Pyridine-4-carbonitrile)silver(I) Nitrate and Bis(4-benzoylpyridine)Silver(I) Nitrate Monohydrate

1987 ◽  
Vol 40 (9) ◽  
pp. 1603 ◽  
Author(s):  
S Gotsis ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
Complex Cation ◽  
Lewis Base ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Silver Atoms ◽  
Close Contacts

The crystal structures of the title compounds, [Ag(C6H4N2),] (NO3), (I), and [Ag(C12H9NO)2] (NO3).H2O, (2), have been determined by single-crystal X-ray diffraction methods at ~295 K, being refined by full-matrix least-squares methods to residuals of 0.042 and 0.044 for 1814 and 3434 independent 'observed' reflections respectively. Crystals of (1) and (2) are triclinic P1; for (1) a, 27.954(7), b 6.354(2), c 3.710(1)�, α 87.55(3), β 86.21(2), γ 89.35(2)�, Z 2; for (2), a 17.036(5), b 8.691(3), c 7.849(3) �, α � 107.74(2), β 97 53(2), γ 91 .11(2)�, Z 2. In both structures the formulation is basically a linearly coordinated complex cation/anion as shown above: in (I), Ag-N are 2.214(4), 2.203(4) � with N-Ag-N, 162.2(2)"; in (2), Ag-N are 2.146(3), 2.147(3) �, N-Ag-N, 175.3(1)�. The shortest Ag-O contact is found in (1) at 2.693(4)�. No close contacts are found between the silver atoms and cyano or ketonic ligand substituents.

Crystal structure of Tetracyclo[5,3,1,12,6,04,9]dodecane (iceane)

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rigid Body ◽  
Least Squares ◽  
Title Compound ◽  
Molecular Geometry ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Hexagonal Close Packed

The crystal structure of the title compound, C12H18, has been determined at 295 K by X-ray diffraction and refined by full-matrix least squares to a residual of 0.049 for 216 ?observed? reflections; molecular geometry has been corrected for the effects of thermal motion using a rigid body approximation. Crystals are hexagonal, P63/m, a = 6.582(1), c = 11.843(3) Ǻ, Z = 2, the molecules occupying a hexagonal close- packed array.

Röntgenstrukturbestimmung von AlCl3-Pyridin-Addukten: Der strukturelle Aufbau im trans-Dichlorotetrakis(pyridin)aluminium(III)- Tetrachloroaluminat(III) und im Trichlorotris(pyridin)aluminium(III) / X-ray Diffraction Study of AICl3-Pyridine Adducts: The Crystal Structure of trans-Dichlorotetrakis(pyridine)aluminium(III)tetrachloroaluminat(III) and of Trichlorotris(pyridine)aluminium(III)

1982 ◽  
Vol 37 (10) ◽  
pp. 1312-1315 ◽  
Author(s):  
Peter Pullmann ◽  
Karl Hensen ◽  
Jan W. Bats
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
The Mean

Abstract Crystals of [Al(C5H5N)4Cl2][AlCl4] are orthorhombic, Pna21, Z = 4, a = 18.522(7), b = 15.141(5), c = 9.593(3) Å, V = 2690(2) Å3 , Dc = 1.440 g/cm3 . The structure has been solved from 5968 diffractometer measured intensities and refined by full-matrix least squares to Rw(F) = 0.032. The crystal structure shows the complex to be trans-dichloro-tetrakis(pyridine)aluminium(III) tetrachloroaluminat(III). The mean trans Al-Cl-and trans Al-N-distances in the octahedron are 2.279(3) and 2.070(4) Å, respectively. Crystals of Al(C5H5N)3Cl3 are monoclinic, P21/c, Z = 4, a = 7.261(2), b = 29.961(4), c = 8.624(1) Å, β = 98.12(2)°, V -1857(1) Å3 , DC = 1.326 g/cm3 . The structure has been solved from 4707 diffractometer measured intensities and refined to Rw(F) = 0.028. The crystal structure shows octahedral complexes AlCl3·3 (C5H5N) with trans geometry. The Al-N-distance trans to chlorine (2.096(2) Å) is significantly longer than the two other Al-N-distances (mean 2.072(2) Å).

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