Molecular symmetry and fluorine-containing supramolecular synthons as structure-differentiating agents in some “bridge-flipped” isomeric bis-benzylideneanilines

CrystEngComm ◽  
2014 ◽  
Vol 16 (31) ◽  
pp. 7226-7235 ◽  
Author(s):  
William H. Ojala ◽  
Barjeta Balidemaj ◽  
Jenna A. Johnson ◽  
Sarah N. Larson ◽  
Charles R. Ojala
Keyword(s):  
Crystal Structures ◽  
Molecular Symmetry ◽  
Supramolecular Synthons ◽  
Differentiating Agents

The non-isomorphous crystal structures of “bridge-flipped” isomers1–5are described and are compared to those of recently reported fluorinated benzylideneanilines.

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.

Lewis-Base Adducts of Group-1B Metal(I) Compounds. XXIII. Synthesis and Structures of the 'Tris(3,5-Dimethylpyridine)Copper(I) Halides, [(C7H9N)3CuX], X = Cl, Br, I

1986 ◽  
Vol 39 (7) ◽  
pp. 1043 ◽  
Author(s):  
JM Dyason ◽  
LM Engelhardt ◽  
PC Healy ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Total Loss ◽  
Lewis Base ◽  
Molecular Symmetry ◽  
X Ray ◽  
Ray Methods

The crystal structures of the title compounds, (C7H9N)3CuX, X = Cl , Br, I [(1), (2), (3)], have been determined by single-crystal X-ray methods at 295 K, being refined to residuals of 0.022, 0.053, 0.047 for 151, 312, 720 independent 'observed' reflections respectively. The three structures containing 3,5-dimethylpyridine have an interesting relationship in symmetry: (1) is rhombohedral , R3m, a 9.050(3)Ǻ, α 110.89(3)°, Z 1; (2) is rhombohedral, R3c, a 10.328(5)Ǻ, α 95.60(4), Z 2; and (3), derived from (2), is monoclinic, Cc, a 13.233(6), b 15.083(7), c 11.491(6)Ǻ, β 98.27(4)°, Z 4. The distances Cu- Cl , Br, I are 2.412(9), 2.51(1), 2.683(3)Ǻ, with Cu-N 2.08(1), 2.02(1), 1.98(2)- 2.15(4)Ǻ respectively. In (1), the symmetry of the molecule, containing pseudo- tetrahedrally coordinated copper, N3CuX, is a full 3 m, with the ligands lying in mirror planes containing the 3 axis; in (2), the ligands rotate about the Cu-N bonds so that the molecular symmetry is 3; and in (3) further distortion of this kind causes total loss of crystallographically imposed symmetry. This descent in symmetry is the converse of that observed in the rhombohedral series [(C6H7N)3CuX] (C6H7N = 3-methylpyridine), and the possible underlying reasons are explored in terms of intra- and inter-molecular X...H interactions.

Influence of aromatic sulfonation on the geometry of [2.2]paracyclophane: crystal structures of one sulfonate, one disulfonic anhydride and five disulfonimides

2001 ◽  
Vol 57 (6) ◽  
pp. 780-790 ◽  
Author(s):  
Dirk J. A. De Ridder ◽  
Kees Goubitz ◽  
Margot Fontijn ◽  
Pavla Čapková ◽  
Eva Dova ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
New York ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structural Changes ◽  
Symmetry Plane ◽  
Academic Press ◽  
Molecular Symmetry ◽  
X Ray Diffraction ◽  
X Ray

The crystal structures of potassium [2.2]paracyclophane-4-sulfonate (1), [2.2]paracyclophane-4,15-disulfonic anhydride (2), [2.2]paracyclophane-4,15-disulfonimide (3), N-n-propyl-[2.2]paracyclophane-4,15-disulfonimide (4), N-isopropyl-[2.2]paracyclophane-4,15-disulfonimide (5), N-cyclopropyl-[2.2]paracyclophane-4,15-disulfonimide (6) and N-phenyl-[2.2]paracyclophane-4,15-disulfonimide (7) were established by single-crystal X-ray diffraction. The structural changes caused by sulfonation are discussed with respect to the parent [2.2]paracyclophane (tricyclo[8.2.2.24,7]hexadeca-4,6,10,12,13,15-hexaene). The main features are a change in the non-bonding distances between the para-phenylene rings and a rotation of these rings with respect to the molecular symmetry plane. The rings are rotated away from each other in the case of monosulfonation (1), but are rotated in the opposite way in the case of the disulfonic anhydride (2) or the disulfonimide compounds (3)–(7). The results are also discussed in terms of the parameters proposed by Keehn [(1983), Organic Chemistry, A Series of Monographs 45, edited by P. H. Keehn & S. M. Rosenfeld, Vol. 1, pp. 69–238. New York: Academic Press] showing that (bonded and non-bonded) angles involving the para-phenylene rings are mainly affected.

Three Crystal Structures of Terephthalic Acid Salts of Simple Amines

2009 ◽  
Vol 64 (7) ◽  
pp. 865-870 ◽  
Author(s):  
Peter G. Jones ◽  
Jerzy Ossowski ◽  
Piotr Kus ◽  
Ina Dix
Keyword(s):  
Oxygen Atom ◽  
Crystal Structures ◽  
Terephthalic Acid ◽  
Inversion Symmetry ◽  
Supramolecular Synthons ◽  
Twofold Axis ◽  
Water Oxygen ◽  
Water Oxygen Atom ◽  
Acid Salts

Diphenethylamine forms two adducts (1 : 1, 1a and 2 : 1, 1b) with terephthalic acid (H2TPA). The former is bis(diphenethylammonium)H2TPA・TPA2− and the latter is bis(diphenethylammonium) ・TPA2−. The amine cis-2,6-dimethylpiperidine forms a hydrated 2 : 1 adduct, bis(2,6-dimethylpiperidinium) ・TPA2−・H2O (2). The crystal structures of all three compounds were determined. All H2TPA and TPA2− residues display inversion symmetry, while the water oxygen atom of 2 lies on a twofold axis. Packing analyses have identified some supramolecular synthons known from related structures.

scholarly journals Crystal structures ofp-substituted derivatives of 2,6-dimethylbromobenzene with ½ ≤Z′ ≤ 4

2016 ◽  
Vol 72 (12) ◽  
pp. 1762-1767
Author(s):  
Angélica Navarrete Guitérrez ◽  
Gerardo Aguirre Hernández ◽  
Sylvain Bernès
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Functional Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Structure Feature ◽  
Non Covalent Interactions ◽  
Derivatives Of ◽  
Covalent Interactions

The crystal structures of four bromoarenes based on 2,6-dimethylbromobenzene are reported, which are differentiated according the functional groupXplacedparato the Br atom:X= CN (4-bromo-3,5-dimethylbenzonitrile, C9H8BrN), (1),X= NO2(2-bromo-1,3-dimethyl-5-nitrobenzene, C8H8BrNO2), (2),X= NH2(4-bromo-3,5-dimethylaniline, C8H10BrN), (3) andX= OH (4-bromo-3,5-dimethylphenol, C8H9BrO), (4). The content of the asymmetric unit is different in each crystal,Z′ = ½ (X= CN),Z′ = 1 (X= NO2),Z′ = 2 (X= NH2), andZ′ = 4 (X= OH), and is related to the molecular symmetry and the propensity ofXto be involved in hydrogen bonding. In none of the studied compounds does the crystal structure feature other non-covalent interactions, such as π–π, C—H...π or C—Br...Br contacts.

Automatic detection of molecular symmetry in the Cambridge Structural Database

2001 ◽  
Vol 57 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Jason C. Cole ◽  
Jing Wen Yao ◽  
Gregory P. Shields ◽  
W. D. S. Motherwell ◽  
Frank H. Allen ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Random Perturbation ◽  
Point Group ◽  
Automatic Detection ◽  
Group Symmetry ◽  
Point Group Symmetry ◽  
Molecular Symmetry ◽  
Small Random Perturbation ◽  
Exact Symmetry ◽  
Structural Database

A method for the detection of approximate molecular symmetry in crystal structures has been developed. The point-group symmetry is assigned to each molecule and the relevant symmetry elements can be visualized, superimposed on the molecule. The method has been validated against reference structures with exact symmetry subjected to small random perturbation.

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