MITHRIL–an integrated direct-methods computer program

O(1)----C(7) 1.218 (8) C(1)---C(2) 1.516 (9) O(2)----C(8)1.231 (8)Intensities were corrected for Lorentz and polarization effects. The structure was solved by direct methods using MITHRIL (Gilmore, 1984 NOELLE EHLINGER AND MONIQUE PERRIN 1847 1993). The properties of these azocalixarenes are often compared with those of their non-cyclic analogues (Shinkai et al., 1989;Nomura, Taniguchi & Tamura, 1989;Nomura, Taniguchi & Otsuji, 1993). It is for this purpose that we describe here the crystal structure of 4-(3,5-dimethyl-4-hydroxyphenylazo)benzenesulfonic acid. The crystallization of this product gives two kinds of crystals of the monohydrate: cubes (I) and needles (II). In (I), intermolecular hydrogen bonds have been found between the water molecule and 0(2) and 0(4) of two sulfonic groups, and O(1) of the hydroxy group. There is also a bifurcated hydrogen bond between N(2) and two O atoms [0(2) and 0(4)] of two sulfonic groups, an H atom being located at 0.959/~ from N(2). This interaction corresponds to a charge-transfer interaction because a proton was transferred from the sulfonic group to N(2) of the azo group. MeIn (II), intermolecular hydrogen bonds have been found between the water molecule and 0(3) and 0(4) of two sulfonic groups, and O(1) of the hydroxyl group. We also find a fourth interaction between N(2) and 0(2) which corresponds to a charge-transfer interaction, the H atom being located at 0.945/~, from N(2).A-5-Z. ExperimentalThe title compound was prepared by a diazo coupling reaction of 2,6-dimethylphenol and diazoted sodium sulfanilate in water at ca 275 K. At the end of the reaction, the red solution was treated with hydrochloric acid and p-(4-hydroxy-3,5-dimethylphenylazo)benzenesulfonic acid was isolated by filtration and recrystallized from water (63% yield). IH NMR (D20): 6 2.18 (6H, s, CH3), 7.43 (2H, s, ArH in the phenol moiety), 7.70 and 7.87 p.p.m. (both 2H, d, ArH in the 4-sulfonic phenyl moiety). Elemental analysis: calculated for Cn4HI4N204S.H20, C 51.84, H 4.97, N 8.64, S 9.88%; found, C 51.70, H 4.91, N 8.66, S 9.89%. Form (I) Crystal dataCI4Hi4N204S.H20 NOELLE EHLINGER AND MONIQUE PERRIN 18492.541 (4) 151 ( -177.9 In both structures, H atoms bonded to C atoms were placed in calculated positions. H atoms bonded to N atoms and O atoms were located in difference maps. ©1995 International Union of CrystallographyPrinted in Great Britain -all rights reserved AbstractIn the molecule of the title compound, C15H1502P, the C==C--~ fragment has an S-cis conformation. The methoxyphenyl ring assumes an almost coplanar arrangement with the ~ bond and is almost perpendicular to the phenyl ring.

mentioning

confidence: 99%

4-(4-Hydroxy-3,5-dimethylphenylazo)benzenesulfonic Acid

Ehlinger¹,

Perrin²

1995

“…The direct methods program MITHRIL (Gilmore, 1984) in the TEXSAN structure analysis package (Molecular Structure Corporation, 1989) was used to generate an E map from which the initial positions of the C and O atoms of the organic portion of the structure were assigned. Fourier difference methods were used to locate the positions of the Na atom, the water O atom and the H atoms.…”

mentioning

confidence: 99%

Structure of the sodium salt of 1,4,5,8-naphthalenetetracarboxylic acid 4,5-anhydride hydrate

Fitzgerald

Gallucci²,

Gerkin³

1992

Abstract. Sodium hydrogen 1,3-dioxo-lH,3H-naphtho [1,8-cd]pyran-6,7-dicarboxylate hydrate, Na[CI4HsOT].H20, Mr=326.2, triclinic, P1, a = 9.520 (2), b = 9.549 (3), c = 7.860 (1) A, a = 105.88 (2), /3 = 110.29 (1), y= 100.89 (2) °, V= * To whom correspondence should be addressed.0108-2701/92/030460-06503.00 611.9 (3) A 3, Z = 2, Dx = 1.77 g cm -3, A(Mo K~) = 0.71073 A, /z = 1.67 cm i, F(000) = 332, T = 295 K, R --0.042 for 1665 unique reflections having I> 3tri. The organic portion of this structure demonstrates near-C2 symmetry with a pseudo-twofold axis coincident with the central C---C naphthalene ring bond. The atoms of the naphthopyran three-ring

“…The structure was solved by direct methods using MITHRIL (Gilmore, 1984) and DIRDIF (Beurskens et al, 1984). Unrefined H atoms were introduced in theoretical positions with dx-n = 0.95 ~, and fixed isotropic B = 1.2 x B of the bonded atom.…”

Section: Methodsmentioning

confidence: 99%

Structure of a 1:1 complex between L-Asp-L-Phe and L-His-Gly

Görbitz

Etter²

1993

Both molecules occur in slightly folded conformations, characterized by q~2 = -93 .7° in L-His-Gly and an unusual ~P2 = 60.2 ° in L-Asp-L-Phe. The peptide linkage of L-His-Gly displays a substantial deviation from planarity with w~ = -163.5 °. The crystal packing is arranged in thick hydrophilic layers separated by hydrophobic sheets composed of L-Phe aromatic side chains. There are numerous hydrogen bonds, including an extremely short contact [O...N= 2.532 (6)A] between the ionized L-Asp and L-His side chains. Comment