Steric hindrance and molecular conformation Pt. 9. Crystal and molecular structure of 5,6-dichloro-11,12-diphenylnaphthacene

1965 ◽  
Vol 5 (3) ◽  
pp. 390-405 ◽  
Author(s):  
R. L. Avoyan ◽  
A. I. Kitaigorodskii ◽  
Yu. T. Struchkov
1975 ◽  
Vol 53 (14) ◽  
pp. 2194-2198 ◽  
Author(s):  
Arthur Camerman ◽  
Norman Camerman

The crystal and molecular structure of sulthiame, (N-[4′-sulfamylphenyl]-l,4-butansultam), one of a series of carbonic anhydrase inhibitors that have gained wide use as antiepileptic agents, has been determined in order to compare the stereochemistry of this compound to that of other antiepileptics. Crystals of sulthiame are orthorhombic, space group Pca21; with cell dimensions a = 8.267, b = 17.750, c = 8.651 Å. The structure was determined by Patterson and Fourier methods and refined to a final R value of 0.039.Sulthiame molecular conformation differs markedly from that of diphenylhydantoin and other anticonvulsant drugs, suggesting a different mechanism of action for this compound. If the sulfonamide group is removed from sulthiame, however, the resulting molecule, although no longer a carbonic anhydrase inhibitor, does retain weak antiepileptic activity and does bear a weak conformational resemblance to the other noncarbonic anhydrase inhibitor anticonvulsant drugs.


1981 ◽  
Vol 36 (12) ◽  
pp. 1526-1531 ◽  
Author(s):  
Klaus von Deuten ◽  
Günter Klar

The title compound crystallizes with an orthorhombic P cell, a = 893.5(1), b = 949.2(2), c = 1520.6(3) pm; Z = 4, space group Pnab. Its molecular conformation has crystallographic C2-symmetry with one phenylene ring in the plane of the three oxygen atoms, the other rings extending almost perpendicularly above and below this plane. The two kinds of oxygen atoms in the molecule show characteristic differences with respect to CO bond lengths and COC bond angles; only the oxygen lying on the C2-axis (joining the "perpendicular" rings) exhibits π-interactions with its phenylene rings. The influence of electronic and steric factors on the preferred conformation of the class of compounds (arylene)3X3 is pointed out.


1983 ◽  
Vol 61 (7) ◽  
pp. 1603-1607 ◽  
Author(s):  
Kathy A. Beveridge ◽  
Gordon W. Bushnell ◽  
Reginald H. Mitchell

Conformations in a variety of cyclophane structures are discussed, as determined by X-ray diffraction in crystals and by 1Hmr in solution. Established nomenclature is brought forward (syn/anti and synclinal/anticlinal) and used to deal with an intermediate case which has been examined by both techniques. The crystal and molecular structure of the title compound, C16H16S4, is determined and refined to R = 0.0497. The crystal is orthorhombic, space group Pbca, a = 16.593(2), b = 10.018(2), c = 19.407(3) Å at 25(2) °C, Z = 8, Dcalc = 1.386 g cm−3. The molecular conformation in the crystal is anticlinal with a dihedral angle between the benzene rings of 101°. The benzene rings are displaced laterally by 0.727 Å and the sequence of torsion angles is similar in the two bridging chains.


(CF 3 ) 4 C 5 O. C 5 H 5 . Co crystallizes in a monoclinic cell: a = 25·39 Å, b = 8·68 Å, c = 14·40 Å, β = 94·8°; Z = 8, C 2/ c . A least squares analysis of three-dimensional precession data has reduced the discrepancy index to 0·088, cobalt-carbon distances being reported with an e. s. d. of 0·023 Å and other bond lengths with an e. s. d. of 0·032 Å. A system of σ - and π -bonding from the cyclopentadienone ligand to the cobalt atom is evident from the molecular conformation, a comparison being made with the stereochemistry and bonding in other organometallic complexes. Other features of the molecular and crystal structure are discussed in relation to features of the non-bonded atomic interactions.


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