Crystal structures of nitron and its non-stoichiometric hydrochloride

1980 ◽  
Vol 33 (10) ◽  
pp. 2237 ◽  
Author(s):  
JR Cannon ◽  
CL Raston ◽  
AH White
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Molecular Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Block Diagonal

The crystal structures of the hemi-ethanolate of nitron, C20H16N4(C2H6O)0.5, and of a non-stoichiometric hydrochloride of nitron, C20H16N4(HCl)1.7(H2O)3.3, have been determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal least squares to residuals of 0.069 (2049 'observed' reflections) and 0.055 (1915), respectively. Crystals of the hemi-ethanolate of nitron are monoclinic P21/n, a 12.697(6), b 15.821(5), c 19.064(6) Ǻ, β 108.79(3)°, Z 8. Crystals of the non-stoichiometric hydrochloride of nitron are also monoclinic C2/c, a 25.41(1), b 5.968(6), c 29.40(2) Ǻ, β 103.53(5)°, Z 8. Despite some unusual features in their molecular geometry, these structures are consistent with the mesoionic character of nitron.

The Molecular Geometry of Diastereoisomeric Bis[α-(9-anthryl)ethyl] Ethers

1985 ◽  
Vol 38 (9) ◽  
pp. 1417 ◽  
Author(s):  
H Becker ◽  
VA Patrick ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Dihedral Angle ◽  
Molecular Geometry ◽  
Dihedral Angles ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Meso Form ◽  
Aromatic Systems

The crystal structures of racemic bis [α-(9-anthryl)] ether and its meso form have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to residuals of 0.053 and 0.041 for 1868 and 3568 independent 'observed' reflections respectively. Crystals of the racemate are orthorhombic, Pcab, a 23.07(1), b 19.85(2), c 10.241(8) Ǻ, Z 8. Crystals of the meso form are triclinic, Pī , a 19.032(12), b 14.207(11), c 9.451(8) Ǻ, α 79.46(6), β 89.68(6), γ 68.97(5)°, Z 4. In the racemate , the dihedral angle between the methyl groups along the ether bonds is 12°, and the short axes of the anthracene moieties lie at an angle of about 120°. In the meso compound, for the two molecules the dihedral angles between the methyl groups along the ether bonds are 90 and 93°, the angle between the two anthracene moieties is 90°, and the interplanar angles between the partly overlapping aromatic systems are 46 and 43°.

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.

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.

Crystal structures of hexa(N-methylurea)cobalt(II) sulfate and thiosulfate

1980 ◽  
Vol 33 (2) ◽  
pp. 425 ◽  
Author(s):  
BN Figgis ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Complex Cation ◽  
X Ray Diffraction ◽  
Threefold Axis ◽  
X Ray

The crystal structures of the title compounds, [Co(C2H6N2O)6](SO4)(1) and[Co(C2H6N2O)6](S2O3) (2), have been determined at 295 K by X-ray diffraction using diffractometer data and refined by least squares to residuals of 0.042 (1), 0.043 (2) [875 and 926 reflections with I > (3σ(I)]. Crystals are trigonal, R 3c, a 1.4890(1) nm, α 43.34(1)° (1); a 1.4760(3) nm, α 44.53(1)° (2), Z 2. The compounds are isostructural; the complex cation has 3 symmetry, Co-O, 209.6(2) (1), 209.9(2) pm (2); the geometry of the ligand is well defined and precise, but the anions, located at sites of symmetry 32, are disordered. ��� The cobalt environment is distorted from Oh symmetry, being compressed along the threefold axis.

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.

Chemistry and Crystal Structures of Some Constituents of Zingiber cassumunar

1979 ◽  
Vol 32 (1) ◽  
pp. 71 ◽  
Author(s):  
T Amatayakul ◽  
J Cannon ◽  
P Dampawan ◽  
T Dechatiwongse ◽  
RF Giles ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Structure Determination ◽  
Aromatic Compounds ◽  
Crystal Structure Determination ◽  
The Novel ◽  
X Ray ◽  
Zingiber Cassumunar ◽  
Block Diagonal

The novel aromatic compounds cis-3-(2',4',5'-trimethoxyphenyl)-4-[(E)-2''',4''',5'''-trimethoxy-styryl]cyclohex-1-ene(1), cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-3''',4'''-dimethoxystyryl]cyclohex-1-ene (2), a substance assigned the tentative structure cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-2''',4''',5'''- trimethoxystyryl]cyclohex-1-ene (3),(E)-4-(3',4'-dimethoxypheny1)but-3-en-1-ol (5), (E)-4-(3',4'-dimethoxypheny1)but-3-en-1-yl acetate (6), and 8-(3',4'-dimethoxyphenyl)-2-methoxynaphtho-1,4- quinone (7) have been isolated from the rhizomes of Zingiber cassurnunav Roxb. (Zingiberaceae). The crystal structures of the cyclohexene derivative (1) and the quinone (7) have been determined from X-ray diffractometer data at 295 K and refined by block diagonal least squares to residuals of 0.046 (2099 'observed' reflections) and 0.093 (1246), respectively. Crystals of compound (1) are triclinic, P1, a 18.027(12), b 10.037(9), c 6.530(5) α, 84.22 (7), β 81.87 (6), γ 85.72 (6)�, Z 2. Crystals of the quinone (7) are monoclinic, P21/a, a 22.89 (1), b 8.022 (5), c 8.458 (5) �, β 91.98 (5)�, Z 4. Although the latter crystal structure determination is imprecise, due largely to the very small size of the crystal available, the solution is unambiguous. A simple two-step synthesis of the quinone (7) has been achieved.

Crystal structures of (RS)-Di-μ-chloro-tetrakis(ethane-1,2-diamine)nickel(II) dichloride and diperchlorate

1978 ◽  
Vol 31 (2) ◽  
pp. 285 ◽  
Author(s):  
GA Bottomley ◽  
LG Glossop ◽  
CL Raston ◽  
AH White ◽  
AC Willis
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Complex Cation ◽  
Dimeric Complex ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Sites

The crystal structures of [(en)2NiCl2Ni(en)2] Cl2 (1) and [(en)2NiCl2Ni(en)2] (ClO4)2 (2) have been redetermined from single- crystal X-ray diffraction data at 295(1) K and refined by least squares to residuals of 0.073 and 0.052 respectively for 1345 and 1605 'observed' reflections respectively. Crystals of (1) are monoclinic, P21/n, a 14.053(4), b 11.309(3), c 6.326(1) Ǻ, β 94.22(2)�, Z 2. Crystals of (2) are monoclinic, P21/n, a 8.885(12), 6 19.707(20), c 7.120(8) Ǻ, β 108.99(4)�, Z 2. In both (1) and (2), a dimeric complex cation is observed, a pair of cis coordination sites about the nickel in each case being occupied by the bridging chlorines; the latter are asymmetric (Ni-Cl, 2.461(3), 2.551(3)(1); 2.461(3), 2.512(3) Ǻ (2)).

Crystal structures of Bis[(ethane-1,2-diyl)bis(diphenylphosphine)]-palladium(II) and -platinum(II) dichloride dichloromethane and Dichloro[(ethane-1,2-diyl)bis(diphenylphosphine)]platinum(II) dichloromethane

1984 ◽  
Vol 37 (11) ◽  
pp. 2193 ◽  
Author(s):  
LM Engelhardt ◽  
JM Patrick ◽  
CL Raston ◽  
P Twiss ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Centrosymmetric Molecule ◽  
Platinum Analogue

The crystal structures of the title compounds have been established by single-crystal X-ray diffraction techniques at 295 K, being refined by least squares to residuals of 0.043, 0.036, 0.036 for 2057, 3176 and 3468 independent 'observed' reflections respectively. Crystals of [Pd(diphos)2] C12 (1) (diphos = Ph2P(CH2)2PPh2) are monoclinic, P21/c, with a 12.779(9), b 18.084(10), c 12.942(6) �, β 119.29(5)�, 22; for the isostructural platinum analogue (2), a 12.789(4), b 18.099(7), c 12.965(4) �, β 1l9.39(2)�. Crystals of [PtCl2(diphos)].CH2Cl2, (3), are orthorhombic, P212121, with a 21.360(6), b 13.499(4), c 9.551(5)� Z 4. Complexes (1) and (2) are also solvated but the nature of the solvation is complicated by disorder and less clearcut than in (3). In (1), Pd-P distances are 2.342(2), 2.347(2) � in a centrosymmetric molecule; in (2), Pt-P distances are 2.332(2), 2.335(2) �, while in (3), Pt-P distances are 2.230(2), 2.224(3) � and Pt-Cl are both 2.355(2) � [cf. 2.233(2), 2.226(2), (2.361(2), 2.357(2))� respectively for the previously studied palladium analogue].

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.

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