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

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).

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White

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.


1977 ◽  
Vol 30 (10) ◽  
pp. 2195 ◽  
Author(s):  
RM Christie ◽  
RW Rickards ◽  
KJ Schmalzl ◽  
D Taylor

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).


1978 ◽  
Vol 31 (5) ◽  
pp. 993 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
JK Yandell

The crystal structure of the title compound, [Co(C2N2H8)2(C3N2H4)(SO3)] ClO4,2H2O has been determined by X-ray diffraction, using diffractometer data, at 295 K, and refined by full-matrix least squares to a residual of 0.071 for 3425 ?observed? reflections. Crystals are orthorhombic, Pcmn, a 15.822(9), b 11.924(6), c 9.261(2) Ǻ, Z 4. The imidazole and sulfite ligands are trans in the cation, which has m symmetry (Co-S 2.223(2); Co-N 2.008(4) Ǻ). <Co-N(en)> is 1.964Ǻ. The apparent thermal motion of the sulfite about the Co-S axis is very high. The internal internuclear distances are compared to the data reported for series of similar complexes in which trans effects are observed.


1984 ◽  
Vol 37 (8) ◽  
pp. 1763
Author(s):  
IR Castleden ◽  
LM Engelhardt ◽  
SR Hall ◽  
AH White

The crystal structure of 8-hydroxy-1H-naphtho[2,1,8-mna]xanthen-1-one, C19H10O3, obtained as an indefinite methanolsolvate, has been determined at 295K by single-crystal X-ray diffraction methods, being refined by full matrix least squares to a residual of 0.056 for 892 independent 'observed' reflections. Crystals are monoclinic, P21/c, a 5.128(4), b 10.024(9), c 27.45(2) �, β 107.73(6)�, Z 4. The packing of the molecules is typically that of charge-transfer complexes, with an interplanar spacing of c.3.5 �.


1980 ◽  
Vol 33 (5) ◽  
pp. 1073 ◽  
Author(s):  
J Cannon ◽  
V Lojanapiwatna ◽  
C Raston ◽  
W Sinchai ◽  
A White

Plumbagin (1), droserone (2), hydroxydroserone (4) and four new quinones, nepenthone-A, nepenth-one-B, nepenthone-C (17) and nepenthone-E (9), have been isolated from the roots of Nepenthes rafflesiana Jack. A fifth quinone-nepenthone-D-has been detected in the extract and has been assigned the tentative structure (29) from its spectroscopic properties. ��� The crystal structure of nepenthone-E (9) was determined by X-ray diffraction; diffractometer data at 295 K were refined by full-matrix least squares to a residual of 0.061 (1040 'observed' reflections). Crystals of nepenthone-E (9) are triclinic, Pī a 7.579 (4), b 7.764 (5), c 10.806 (7) Ǻ, α 70.86 (4), β 101.40 (5), γ 91.70 (5)°, Z 2. ��� The structure of nepenthone-C (17) has been confirmed by an unambiguous synthesis. A synthesis of 2,7,8-trimethoxy-3-methyl-5,6-methylenedioxynaphtho-1,4-quinone (49) has revealed that this substance (49) is not identical with the O,O-dimethyl ether of nepenthone-A, and it is suggested that nepenthone-A is either the 5- or 8-O-methyl ether of 2,5,8-trihydroxy-3-methyl-6,7-methylenedioxy-naphtho-1,4-quinone [(36) or (37), respectively].


1984 ◽  
Vol 37 (5) ◽  
pp. 921 ◽  
Author(s):  
PC Healy ◽  
JM Patrick ◽  
AH White

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.


1975 ◽  
Vol 53 (8) ◽  
pp. 1139-1143 ◽  
Author(s):  
Robert Melanson ◽  
Joseph Hubert ◽  
F. D. Rochon

The molecular and crystal structure of the [Pt(dien)Br]Br complex (dien = diethylenetriamine) has been studied by X-ray diffraction. The compound belongs to the orthorhombic Pca21 space group and the cell parameters are: a = 14.211, b = 4.940, c = 13.450 Å, and Z = 4. The refinement of the positional and anisotropic thermal parameters, carried out by full matrix least squares calculations, converged to R = 0.039 and Rw = 0.036.The coordination around the platinum atom is planar. The crystal consists of alternate layers of [Pt(dien)Br]+ cations and Br− ions parallel to the ac plane.


1973 ◽  
Vol 51 (13) ◽  
pp. 2073-2076 ◽  
Author(s):  
I. D. Brown ◽  
C. J. L. Lock ◽  
Che'ng Wan

One of the compounds obtained by reacting acetylacetone with oxoethoxodichlorobis(triphenylphosphine)rhenium(V) has been shown by single crystal X-ray diffraction to be trans-dichlorobis(pentane-2,4-dionato)rhenium(IV). The crystals are triclinic, a = 8.032(4), b = 8.344(6), c = 7.429(6) Å, α = 118.1(2), β = 92.3(2), γ = 55.5(2)°, [Formula: see text], Z = 1. Intensities were measured with a microdensitometer from photographs recorded on an integrating precession camera. Of the 991 measured reflections all were observed and 984 were used in the refinement. The structure was refined by full matrix least squares to an R2 value of 0.0685. The compound was found to be a trans-monomer, in contrast to the dimeric structure claimed to exist in solution. The ligand atoms bonded to rhenium lie almost exactly at the apices of an octahedron and the bond lengths (Re—Cl, 2.326(8); Re—O1, 1.97(1); Re—O2, 2.01(1) Å) are in the range expected.


1978 ◽  
Vol 31 (9) ◽  
pp. 1927 ◽  
Author(s):  
DL Kepert ◽  
CL Raston ◽  
NK Roberts ◽  
AH White

The crystal structure of the title compound, [Tl(S2CNEt2)3], has been determined by single-crystal X-ray diffraction methods at 295 K and refined by full-matrix least squares to a residual of 0.050 for 2517 'observed' reflections. Crystals are monoclinic, with space group A2/a, a 14.789(7), b 10.428(4), c 18.207(9) Ǻ, β 118.11(4)°, Z 4, and are isostructural with those of the previously determined gallium and indium analogues, the molecule having 2 symmetry with <Tl-S> 2.666 Ǻ. As in the dimethyl/thallium analogue, the departure of the TlS6 core symmetry from 3 is large and is examined in terms of electron-pair repulsion theory.


1991 ◽  
Vol 246 ◽  
Author(s):  
Yutaka Emura ◽  
Takuya Ohba ◽  
Kazuhiro Otsuka

AbstractCrystal structure of the ζ2' martensite in a Au-49.5at%Cd ally has been analyzed by the single crystal x-ray diffraction method. The crystal lattice was trigonal and the lattice constants were a:0.8095(3) and c=o.57940(6) nm. There were 18 atoms in a unit cell. The space group was P3, which was different from that previously determined by Vatanayon and Hehemann. The structure was refined by the full matrix least squares method to a final R factor of 7.8% and a weighted R factor of 4.1%.


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