scholarly journals A redetermination from the original data of the crystal structure of 2-amino-4,6-dimethoxypyrimidin-1-ium 4-aminobenzoate

2016 ◽  
Vol 72 (4) ◽  
pp. 512-515
Author(s):  
Jan Fábry
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Primary Amine ◽  
Original Data ◽  
Acta Cryst ◽  
Amine Groups

The title structure, C6H9.5N3O20.5+·C7H6.5NO20.5−, which might be named schematically as 2-amino-4,6-dimethoxypyrimidine-(μ2-hydrogen)-4-aminobenzoate to indicate a bridging H atom, has been redetermined from the data published by Thanigaimani, Muthiah & Lynch [Acta Cryst.(2006), E62, o2976–o2978]. The improvement of the present redetermination consists in a released geometry of the primary amine groups, which were originally assumed to be planar, as well as in a redetermination of the position of the hydroxy H atom. This H atom, whose parameters were originally constrained, turns out to be situated about the centre of the O...N hydrogen bond in two disordered positions with occupancies of 0.5 each.

A structural study of (1RS,2SR,3RS,4SR,5RS)-2,4-dibenzoyl-1,3,5-triphenylcyclohexan-1-ol chloroform hemisolvate and (1RS,2SR,3RS,4SR,5RS)-2,4-dibenzoyl-1-phenyl-3,5-bis(2-methoxyphenyl)cyclohexan-1-ol

2015 ◽  
Vol 71 (6) ◽  
pp. 491-498 ◽  
Author(s):  
Mikhail E. Minyaev ◽  
Dmitrii M. Roitershtein ◽  
Ilya E. Nifant'ev ◽  
Ivan V. Ananyev ◽  
Tatyana V. Minyaeva ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Single Crystals ◽  
Structural Study ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Nmr Studies ◽  
Acta Cryst

(1RS,2SR,3RS,4SR,5RS)-2,4-Dibenzoyl-1,3,5-triphenylcyclohexan-1-ol or (4-hydroxy-2,4,6-triphenylcyclohexane-1,3-diyl)bis(phenylmethanone), C38H32O3, (1), is formed as a by-product in the NaOH-catalyzed synthesis of 1,3,5-triphenylpentane-1,5-dione from acetophenone and benzaldehyde. Single crystals of the chloroform hemisolvate, C38H32O3·0.5CHCl3, were grown from chloroform. The structure has triclinic (P-1) symmetry. One diastereomer [as a pair of (1RS,2SR,3RS,4SR,5RS)-enantiomers] of (1) has been found in the crystal structure and confirmed by NMR studies. The dichoromethane hemisolvate has been reported previously [Zhanget al.(2007).Acta Cryst.E63, o4652]. (1RS,2SR,3RS,4SR,5RS)-2,4-Dibenzoyl-3,5-bis(2-methoxyphenyl)-1-phenylcyclohexan-1-ol or [4-hydroxy-2,6-bis(2-methoxyphenyl)-4-phenylcyclohexane-1,3-diyl]bis(phenylmethanone), C40H36O5, (2), is also formed as a by-product, under the same conditions, from acetophenone and 2-methoxybenzaldehyde. Crystals of (2) have been grown from chloroform. The structure has orthorhombic (Pca21) symmetry. A diastereomer of (2) possesses the same configuration as (1). In both structures, the cyclohexane ring adopts a chair conformation with all bulky groups (benzoyl, phenyl and 2-methoxyphenyl) in equatorial positions. The molecules of (1) and (2) both display one intramolecular O—H...O hydrogen bond.

scholarly journals Crystal structure of 4-chloro-2-{(E)-[(3,4-dimethylphenyl)imino]methyl}phenol

2015 ◽  
Vol 71 (6) ◽  
pp. o416-o416 ◽  
Author(s):  
Muhammad Salim ◽  
Muhammad Nawaz Tahir ◽  
Munawar Ali Munawar ◽  
Muhammad Shahid ◽  
Hazoor Ahmad Shad
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Dihedral Angle ◽  
Title Compound ◽  
Three Dimensional ◽  
Aromatic Rings ◽  
Acta Cryst ◽  
Π Interactions ◽  
Compound C ◽  
Dimensional Network

In the title compound, C15H14ClNO, which is isostructural with its bromo analogue [Tahiret al.(2012).Acta Cryst., E68, o2730], the dihedral angle between the planes of the aromatic rings is 2.71 (7)° and an intramolecular O—H...N hydrogen bond closes anS(6) ring. In the crystal, extremely weak C—H...π interactions link the molecules into a three-dimensional network.

Redetermination of rifampicin pentahydrate revealing a zwitterionic form of the antibiotic

2012 ◽  
Vol 68 (5) ◽  
pp. o209-o212 ◽  
Author(s):  
Barbara Wicher ◽  
Krystian Pyta ◽  
Piotr Przybylski ◽  
Ewa Tykarska ◽  
Maria Gdaniec
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Amide Group ◽  
Water Molecules ◽  
Acta Cryst ◽  
Oh Groups ◽  
Zwitterionic Form ◽  
The Family

Rifampicin belongs to the family of naphthalenic ansamycin antibiotics. The first crystal structure of rifampicin in the form of the pentahydrate was reported in 1975 [Gadret, Goursolle, Leger & Colleter (1975).Acta Cryst.B31, 1454–1462] with the rifampicin molecule assumed to be neutral. Redetermination of this crystal structure now shows that one of the phenol –OH groups is deprotonated, with the proton transferred to a piperazine N atom, confirming earlier spectroscopic results that indicated a zwitterionic form for the molecule, namely (2S,12Z,14E,16S,17S,18R,19R,20R,21S,22R,23S,24E)-21-acetyloxy-6,9,17,19-tetrahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-8-[(E)-N-(4-methylpiperazin-4-ium-1-yl)formimidoyl]-1,11-dioxo-1,2-dihydro-2,7-(epoxypentadeca[1,11,13]trienimino)naphtho[2,1-b]furan-5-olate pentahydrate, C43H58N4O12·5H2O. The molecular structure of this antibiotic is stabilized by a system of four intramolecular O—H...O and N—H...N hydrogen bonds. Four of the symmetry-independent water molecules are arrangedviahydrogen bonds into helical chains extending along [100], whereas the fifth water molecule forms only one hydrogen bond, to the amide group O atom. The rifampicin molecules interactviaO—H...O hydrogen bonds, generating chains along [001]. Rifampicin pentahydrate is isostructural with recently reported rifampicin trihydrate methanol disolvate.

An orthorhombic modification of 4,4′-diaminobenzophenone

2006 ◽  
Vol 62 (5) ◽  
pp. o1787-o1788 ◽  
Author(s):  
Yi-Hang Wen ◽  
Yin-Hua He ◽  
Yun-Long Feng ◽  
Seik Weng Ng
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Title Compound ◽  
Compound C ◽  
Orthorhombic Modification ◽  
Amine Groups

The molecule of the title compound, C13H12N2O, uses one of its amine groups to hydrogen bond to two other molecules, affording a layer motif in the crystal structure.

scholarly journals The Amine Group as Halogen Bond Acceptor in Cocrystals of Aromatic Diamines and Perfluorinated Iodobenzenes

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 529
Author(s):  
Erik Uran ◽  
Luka Fotović ◽  
Nikola Bedeković ◽  
Vladimir Stilinović ◽  
Dominik Cinčić
Keyword(s):  
Hydrogen Bond ◽  
Primary Amine ◽  
Halogen Bond ◽  
Halogen Bonds ◽  
Hydrogen Atoms ◽  
Amine Nitrogen Atom ◽  
Aromatic Diamines ◽  
Amine Nitrogen ◽  
Amine Hydrogen ◽  
Amine Groups

In order to study the proclivity of primary amine groups to act as halogen bond acceptors, three aromatic diamines (p-phenylenediamine (pphda), benzidine (bnzd) and o-tolidine (otol)) were cocrystallised with three perfluorinated iodobenzenes (1,4-tetrafluorodiiodobenzene (14tfib), 1,3-tetrafluorodiiodobenzene (13tfib) and 1,3,5-trifluorotriiodobenzene (135tfib)) as halogen bond donors. Five cocrystals were obtained: (pphda)(14tfib), (bnzd)(13tfib)2, (bnzd)(135tfib)4, (otol)(14tfib) and (otol)(135tfib)2. In spite of the variability of both stoichiometries and structures of the cocrystals, in all the prepared cocrystals the amine groups form exclusively I···N halogen bonds, while the amine hydrogen atoms participate mostly in N–H⋯F contacts. The preference of the amine nitrogen atom toward the halogen bond, as opposed to the hydrogen bond (with amine as a donor), is rationalised by means of computed hydrogen and halogen bond energies, indicating that the halogen bond energy between a simple primary amine (methylamine) and a perfluorinated iodobenzene (pentafluoroiodobenze ne) is ca. 15 kJ mol−1 higher than the energy of the (H)NH∙∙∙NH2 hydrogen bond between two amine molecules.

scholarly journals Redetermination of cytosinium hydrogen maleate–cytosine (1/1) from the original data

2016 ◽  
Vol 72 (4) ◽  
pp. 509-511
Author(s):  
Jan Fábry
Keyword(s):  
Hydrogen Bond ◽  
Original Data ◽  
Acta Cryst

The title salt, C4H6N3O+·C4H3O4−·C4H5N3O, has been redetermined from the data published by Benali-Cherif, Falek & Direm [Acta Cryst.(2009), E65, o3058–o3059]. The improvement of the present redetermination consists in the discovery of the splitting of one of the H atoms into two disordered positions, the occupancies of which are equal to 0.55 (2) and 0.45 (2). These H atoms are involved in an N...N hydrogen bond and are shifted towards its centre. The disorder of these H atoms is in agreement with a similar environment of the two independent, but chemically equivalent, cytosinium/cytosine molecules.

scholarly journals Crystal structure of the Anderson-type heteropolyoxometalate; K2[H7CrIIIMo6O24]·8H2O: a redetermination revealing the position of the extra H atom in the polyanion

2015 ◽  
Vol 71 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Hea-Chung Joo ◽  
Ki-Min Park ◽  
Uk Lee
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Water Molecules ◽  
Acta Cryst ◽  
Short Bond ◽  
Medium Strength ◽  
Short Hydrogen Bond ◽  
Normal Hydrogen

The title compound contains a symmetric hydrogen bond in which the H atom does not lie on a crystallographic centre of symmetry. The structure of K2[H7CrIIIMo6O24]·8H2O, namely dipotassium heptahydrogen hexamolybdochromate(III) octahydrate, previously reported by Lee [Acta Cryst. (2007), E63, i5–i7], has been redetermined in order to locate the position of the seventh H atom in the anion. Six of the H atoms are bonded to the six μ3-O atoms and form hydrogen bonds of medium strength either to water molecules or to the terminal O atoms of other polyanions. The seventh H atom forms a very short hydrogen bond between two μ2-O atoms on adjacent polyanions. This short bond, together with two normal hydrogen bonds, link the two crystallographically distinct centrosymmetric polyanions into chains along [011], while the length of this bond [2.461 (3) Å] suggests that the H atom lies at its centre, but unusually for such a bond, this point is not a crystallographic centre of symmetry.

Disorder and conformational analysis of methyl β-D-galactopyranosyl-(1→4)-β-D-xylopyranoside

2011 ◽  
Vol 68 (1) ◽  
pp. o7-o11 ◽  
Author(s):  
Wenhui Zhang ◽  
Allen G. Oliver ◽  
Anthony S. Serianni
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Torsion Angle ◽  
Water Molecules ◽  
Considerable Variability ◽  
Glycosidic Linkage ◽  
Acta Cryst ◽  
Positional Disorder ◽  
Ring Atom

Methyl β-D-galactopyranosyl-(1→4)-β-D-xylopyranoside, C12H22O10, (II), crystallizes as colorless needles from water with positional disorder in the xylopyranosyl (Xyl) ring and no water molecules in the unit cell. The internal glycosidic linkage conformation in (II) is characterized by a ϕ′ torsion angle (C2′Gal—C1′Gal—O1′Gal—C4Xyl) of 156.4 (5)° and a ψ′ torsion angle (C1′Gal—O1′Gal—C4Xyl—C3Xyl) of 94.0 (11)°, where the ring atom numbering conforms to the convention in which C1 denotes the anomeric C atom, and C5 and C6 denote the hydroxymethyl (–CH2OH) C atoms in the β-Xyl and β-Gal residues, respectively. By comparison, the internal linkage conformation in the crystal structure of the structurally related disaccharide, methyl β-lactoside [methyl β-D-galactopyranosyl-(1→4)-β-D-glucopyranoside], (III) [Stenutz, Shang & Serianni (1999).Acta Cryst.C55, 1719–1721], is characterized by ϕ′ = 153.8 (2)° and ψ′ = 78.4 (2)°. A comparison of β-(1→4)-linked disaccharides shows considerable variability in both ϕ′ and ψ′, with the range in the latter (∼38°) greater than that in the former (∼28°). Inter-residue hydrogen bonding is observed between atoms O3Xyland O5′Galin the crystal structure of (II), analogous to the inter-residue hydrogen bond detected between atoms O3Glcand O5′Galin (III). The exocyclic hydroxymethyl conformations in the Gal residues of (II) and (III) are identical (gauche–transconformer).

scholarly journals Crystal structure of bis[1-(2-hydroxyethyl)-2-methyl-5-nitro-1H-imidazole-κN3]silver(I) tetrafluoridoborate methanol monosolvate

2015 ◽  
Vol 71 (3) ◽  
pp. 284-287 ◽  
Author(s):  
Joshua H. Palmer ◽  
Rita K. Upmacis
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Inversion Center ◽  
Acta Cryst ◽  
Metal Compounds

1-(2-Hydroxyethyl)-2-methyl-5-nitro-1H-imidazole (metronidazole, MET) is a medication that is used to treat infections by a variety of anaerobic organisms, but there are relatively few reports of the structures of metal compounds that exhibit coordination of metronidazole. We have demonstrated that MET reacts with AgBF4to give [Ag(MET)2]BF4·CH3OH, in which the AgIcation is coordinated by two MET ligands with atransarrangement. The structure of [Ag(MET)2]BF4exhibits some interesting differences from its nitrate counterpart, [Ag(MET)2]NO3[Funet al.(2008).Acta Cryst.E64, m668]. For instance, although the two MET ligands of both [Ag(MET)2]BF4and [Ag(MET)2]NO3are almost coplanar, the former compound has ananti-like geometry with a molecular inversion center, but the latter has asyn-like arrangement. In the crystal, the BF4−anion is linked by an O—H...F hydrogen bond to the methanol solvent molecule, which is, in turn, linked to the cation by an O—H...O hydrogen bond; the components of the structure are linked by O—H...O hydrogen bonds, forming chains along [001]. One of the MET ligands and the BF4−anion are disordered over two sets of sites with ratios of refined occupancies 0.501 (17):0.499 (17) and 0.539 (19):0.461 (19), respectively.

scholarly journals Crystal structure of memantine–carboxyborane

2019 ◽  
Vol 75 (5) ◽  
pp. 543-546 ◽  
Author(s):  
Theppawut I. Ayudhya ◽  
Arnold L. Rheingold ◽  
Nin N. Dingra
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Amino Group ◽  
Acta Cryst ◽  
Synthesis And Crystal Structure ◽  
Compound C ◽  
Two Component ◽  
Scattering Contribution ◽  
Solvent Molecules

The synthesis and crystal structure of the title compound, C13H24BNO2 [systematic name: 3,5-dimethyladamantanylamine–boranecarboxylic acid or N-(carboxyboranylidene)-3,5-dimethyladamantan-1-amine], derived from the anti-Alzheimer's disease drug memantine is reported. The C—N—B—CO2 unit is almost planar (r.m.s. deviation = 0.095 Å). The extended structure shows typical carboxylic acid inversion dimers linked by pairwise O—H...O hydrogen bonds [O...O = 2.662 (3) Å]. The amino group forms a weak N—H...O hydrogen bond [N...O = 3.011 (3) Å], linking the dimers into [001] chains in the crystal. Highly disordered solvent molecules were treated using the SQUEEZE routine of PLATON [Spek (2015). Acta Cryst. C71, 9–18], which treats the electron density as a diffuse contribution without assignment of specific atom locations. A scattering contribution of 255 electrons was removed. The crystal studied was refined as a two-component twin.

Sign in / Sign up

Export Citation Format

Share Document