scholarly journals Crystal structures of 4-methyl-2-oxo-2H-chromene-7,8-diyl diacetate and 4-methyl-2-oxo-2H-chromene-7,8-diyl bis(pent-4-ynoate)

2016 ◽  
Vol 72 (5) ◽  
pp. 704-708
Author(s):  
Akintunde Akinyemi ◽  
Courtney Thomas ◽  
Willis Marsh ◽  
Ray J. Butcher ◽  
Jerry P. Jasinski ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Triple Bond ◽  
The Other ◽  
Coumarin Derivatives ◽  
Extended Conformation ◽  
Π Stacking ◽  
Planar Part ◽  
Centrosymmetric Dimers

In the structures of the two title coumarin derivatives, C14H12O6, (1), and C20H16O6, (2), one with acetate and the other with pent-4-ynoate substituents, both the coumarin rings are almost planar. In (1), both acetate substituents are significantly rotated out of the coumarin plane to minimize steric repulsions. One acetate substituent is disordered over two equivalent conformations, with occupancies of 0.755 (17) and 0.245 (17). In (2), there are two pent-4-ynoate substituents, the C[triple-bond]C group of one being disordered over two positions with occupancies of 0.55 (2) and 0.45 (2). One of the pent-4-ynoate substituents is in an extended conformation, while the other is in a bent conformation. In this derivative, the planar part of both pent-4-ynoate substituents deviate from the coumarin plane. The packing of (1) is dominated by π–π stacking involving the coumarin rings and weak C—H...O contacts link the parallel stacks in the [101] direction. In contrast, in (2) the packing is dominated byR22(24) hydrogen bonds, involving the acidicspH atom and the oxo O atom, which link the molecules into centrosymmetric dimers. The bent conformation of one of the pent-4-ynoate substituents prevents the coumarin rings from engaging in π–π stacking.

Polymorphs of phenazine hexacyanoferrate(II) hydrate: supramolecular isomerism in a 2D hydrogen-bonded network

2021 ◽  
Vol 77 (2) ◽  
pp. 211-218
Author(s):  
Ivica Cvrtila ◽  
Vladimir Stilinović
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Two Dimensional ◽  
Structural Motifs ◽  
Supramolecular Isomerism ◽  
Other Hand ◽  
Π Stacking ◽  
Hydrogen Bonded

The crystal structures of two polymorphs of a phenazine hexacyanoferrate(II) salt/cocrystal, with the formula (Hphen)3[H2Fe(CN)6][H3Fe(CN)6]·2(phen)·2H2O, are reported. The polymorphs are comprised of (Hphen)2[H2Fe(CN)6] trimers and (Hphen)[(phen)2(H2O)2][H3Fe(CN)6] hexamers connected into two-dimensional (2D) hydrogen-bonded networks through strong hydrogen bonds between the [H2Fe(CN)6]2− and [H3Fe(CN)6]− anions. The layers are further connected by hydrogen bonds, as well as through π–π stacking of phenazine moieties. Aside from the identical 2D hydrogen-bonded networks, the two polymorphs share phenazine stacks comprising both protonated and neutral phenazine molecules. On the other hand, the polymorphs differ in the conformation, placement and orientation of the hydrogen-bonded trimers and hexamers within the hydrogen-bonded networks, which leads to different packing of the hydrogen-bonded layers, as well as to different hydrogen bonding between the layers. Thus, aside from an exceptional number of symmetry-independent units (nine in total), these two polymorphs show how robust structural motifs, such as charge-assisted hydrogen bonding or π-stacking, allow for different arrangements of the supramolecular units, resulting in polymorphism.

Structures of benzoxazine-fused triazoles as potential diuretic agents

2012 ◽  
Vol 68 (8) ◽  
pp. o302-o307 ◽  
Author(s):  
Krishnan Ravikumar ◽  
Balasubramanian Sridhar ◽  
Jagadeesh Babu Nanubolu ◽  
Venkatasubramanian Hariharakrishnan ◽  
Awadesh Narain Singh
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Boat Conformation ◽  
First Report ◽  
Space Groups ◽  
Oxazine Ring ◽  
Diuretic Agents ◽  
Enol Tautomer ◽  
Centrosymmetric Dimers

6,8-Dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C9H5N5O6, (I), a potential diuretic, and its acetylacetone derivative (E)-2-(2-hydroxy-4-oxopent-2-en-3-yl)-6,8-dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C14H11N5O8, (II), both crystallize from methanol but in centrosymmetric and noncentrosymmetric space groups, respectively. To the best of our knowledge, this is the first report of crystal structures of benzoxazine–triazole fused systems. The acetylacetone group in (II) exists as the keto–enol tautomer and is oriented perpendicular to the triazol-3-one ring. Of the two nitro groups present, one is rotated significantly less than the other in both structures. The oxazine ring adopts a screw-boat conformation in (II), whereas it is almost planar in (I). N—H...N and N—H...O hydrogen bonds form centrosymmetric dimers in (I), while C—H...O interactions associate the molecules into helical columns in (II).

Three new phosphoric triamides with a [C(O)NH]P(O)[N(C)(C)]2skeleton: a database analysis of C—N—C and P—N—C bond angles

2014 ◽  
Vol 70 (10) ◽  
pp. 998-1002 ◽  
Author(s):  
Mehrdad Pourayoubi ◽  
Atekeh Tarahhomi ◽  
Arnold L. Rheingold ◽  
James A. Golen
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Database Analysis ◽  
Acta Cryst ◽  
Bond Angles ◽  
Cyclic Amide ◽  
Phosphoric Triamide ◽  
Structural Database ◽  
Phosphoric Triamides

InN,N,N′,N′-tetraethyl-N′′-(4-fluorobenzoyl)phosphoric triamide, C15H25FN3O2P, (I), andN-(2,6-difluorobenzoyl)-N′,N′′-bis(4-methylpiperidin-1-yl)phosphoric triamide, C19H28F2N3O2P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure,N,N′-dicyclohexyl-N′′-(2-fluorobenzoyl)-N,N′-dimethylphosphoric triamide, C21H33FN3O2P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]2skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002).Acta Cryst.B58, 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with theN-methylcyclohexylamide substituent, similar to (III), one structure with the seven-membered cyclic amide azepan-1-yl substituent and one structure with anN-methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linkedviapairs of N—H...O=P hydrogen bonds to form dimers.

scholarly journals Crystal structures of two 6-(2-hydroxybenzoyl)-5H-thiazolo[3,2-a]pyrimidin-5-ones

2015 ◽  
Vol 71 (7) ◽  
pp. 766-771
Author(s):  
Ligia R. Gomes ◽  
John Nicolson Low ◽  
Fernando Cagide ◽  
Fernanda Borges
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dihedral Angles ◽  
Stacking Interactions ◽  
Mechanism Of Formation ◽  
Π Stacking ◽  
Heterocyclic Moiety

The title compounds, 6-(2-hydroxybenzyl)-5H-thiazolo[3,2-a]pyrimidin-5-one, C13H8N2O3S, (1), and 6-(2-hydroxybenzyl)-3-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one, C14H10N2O3S, (2), were synthesized when a chromone-3-carboxylic acid, activated with (benzotriazol-1-yloxy)tripyrrolidinylphosphonium hexafluoridophosphate (PyBOP), was reacted with a primary heteromamine. Instead of the expected amidation, the unusual title thiazolopyrimidine-5-one derivatives were obtained serendipitously and a mechanism of formation is proposed. Both compounds present an intramolecular O—H...O hydrogen bond, which generates anS(6) ring. The dihedral angles between the heterocyclic moiety and the 2-hydroxybenzoyl ring are 55.22 (5) and 46.83 (6)° for (1) and (2), respectively. In the crystals, the molecules are linked by weak C—H...O hydrogen bonds and π–π stacking interactions.

Weak C—H...O and C—H...π hydrogen bonds and π–π stacking interactions in a series of fourN′-[(E)-(aryl)methylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazides

2015 ◽  
Vol 71 (8) ◽  
pp. 647-652 ◽  
Author(s):  
Thais C. M. Nogueira ◽  
Alessandra C. Pinheiro ◽  
James L. Wardell ◽  
Marcus V. N. de Souza ◽  
Jordan P. Abberley ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Weak Interactions ◽  
The Other ◽  
Stacking Interactions ◽  
Screw Axis ◽  
Chiral Structure ◽  
Π Stacking ◽  
Unit Form ◽  
Protective Groups ◽  
Local Inversion

Oxazolidin-2-ones are widely used as protective groups for 1,2-amino alcohols and chiral derivatives are employed as chiral auxiliaries. The crystal structures of four differently substituted oxazolidinecarbohydrazides, namelyN′-[(E)-benzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12N3O3, (I),N′-[(E)-2-chlorobenzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12ClN3O3, (II), (4S)-N′-[(E)-4-chlorobenzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12ClN3O3, (III), and (4S)-N′-[(E)-2,6-dichlorobenzylidene]-N,3-dimethyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C13H13Cl2N3O3, (IV), show that an unexpected mild-condition racemization from the chiral starting materials has occurred in (I) and (II). In the extended structures, the centrosymmetric phases, which each crystallize with two molecules (AandB) in the asymmetric unit, formA+Bdimers linked by pairs of N—H...O hydrogen bonds, albeit with different O-atom acceptors. One dimer is composed of one molecule with anSconfiguration for its stereogenic centre and the other with anRconfiguration, and possesses approximate local inversion symmetry. The other dimer consists of eitherR,RorS,Spairs and possesses approximate local twofold symmetry. In the chiral structure, N—H...O hydrogen bonds link the molecules intoC(5) chains, with adjacent molecules related by a 21screw axis. A wide variety of weak interactions, including C—H...O, C—H...Cl, C—H...π and π–π stacking interactions, occur in these structures, but there is little conformity between them.

scholarly journals Different N—H...π interactions in two indole derivatives

2016 ◽  
Vol 72 (5) ◽  
pp. 699-703 ◽  
Author(s):  
Jamie R. Kerr ◽  
Laurent Trembleau ◽  
John M. D. Storey ◽  
James L. Wardell ◽  
William T. A. Harrison
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Intermolecular Interaction ◽  
Aromatic Ring ◽  
Stacking Interactions ◽  
Indole Derivatives ◽  
Asymmetric Unit ◽  
Π Interactions ◽  
Π Stacking

We describe the syntheses and crystal structures of two indole derivatives, namely 6-isopropyl-3-(2-nitro-1-phenylethyl)-1H-indole, C19H20N2O2, (I), and 2-(4-methoxyphenyl)-3-(2-nitro-1-phenylethyl)-1H-indole, C23H20N2O3, (II); the latter crystallizes with two molecules (AandB) with similar conformations (r.m.s. overlay fit = 0.139 Å) in the asymmetric unit. Despite the presence of O atoms as potential acceptors for classical hydrogen bonds, the dominant intermolecular interaction in each crystal is an N—H...π bond, which generates chains in (I) andA+AandB+Binversion dimers in (II). A different aromatic ring acts as the acceptor in each case. The packing is consolidated by C—H...π interactions in each case but aromatic π–π stacking interactions are absent.

scholarly journals The crystal structures of two novel polymorphs of bis(oxonium) ethane-1,2-disulfonate

2019 ◽  
Vol 75 (11) ◽  
pp. 1586-1589
Author(s):  
Jaroslaw Mazurek ◽  
Ana Fernandez-Casares
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Acta Cryst ◽  
Crystal Forms ◽  
Crystal Density ◽  
Hydrogen Bonding Network

Two novel crystal forms of bis(oxonium) ethane-1,2-disulfonate, 2H3O−·C2H4O6S2 2−, are reported. Polymorph II has monoclinic (P21/n) symmetry, while the symmetry of form III is triclinic (P\overline{1}). Both structures display extensive networks of O—H...O hydrogen bonds. While this network in Form II is similar to that observed for the previously reported Form I [Mootz & Wunderlich (1970). Acta Cryst. B26, 1820–1825; Sartori et al. (1994). Z. Naturforsch. 49, 1467–1472] and extends in all directions, in Form III it differs significantly, forming layers parallel to the ab plane. The sulfonate molecule in all three forms adopts a nearly identical geometry. The other observed differences between the forms, apart from the hydrogen-bonding network, are observed in the crystal density and packing index.

scholarly journals (Cyanido-κC)(2,2-diphenylacetamido-κ2N,O)bis(η5-pentamethylcyclopentadienyl)zirconium(IV)

2014 ◽  
Vol 70 (2) ◽  
pp. m57-m57 ◽  
Author(s):  
Lisanne Becker ◽  
Anke Spannenberg ◽  
Perdita Arndt ◽  
Uwe Rosenthal
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Triple Bond ◽  
Centrosymmetric Dimers

In the title compound, [Zr(C10H15)2(C14H12NO)(CN)], the ZrIVatom is coordinated by two pentamethylcyclopentadienyl ligands, the amidate ligandviathe N and O atoms, and an additional C[triple-bond]N ligand. The four-membered metallacycle is nearly planar (r.m.s. deviation = 0.008 Å). In the crystal, the molecules are connected into centrosymmetric dimersviapairs of N—H...N hydrogen bonds.

scholarly journals Crystal structures of ethyl (2S*,2′R*)-1′-methyl-2′′,3-dioxo-2,3-dihydrodispiro[1-benzothiophene-2,3′-pyrrolidine-2′,3′′-indoline]-4′-carboxylate and ethyl (2S*,2′R*)-5′′-chloro-1′-methyl-2′′,3-dioxo-2,3-dihydrodispiro[1-benzothiophene-2,3′-pyrrolidine-2′,3′′-indoline]-4′-carboxylate

2014 ◽  
Vol 70 (8) ◽  
pp. 94-97 ◽  
Author(s):  
M. P. Savithri ◽  
M. Suresh ◽  
R. Raghunathan ◽  
G. Vimala ◽  
R. Raja ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dihedral Angle ◽  
Ring System ◽  
Membered Ring ◽  
Equatorial Position ◽  
Ring Systems ◽  
Envelope Conformation ◽  
Extended Conformation ◽  
The Mean

In the title compounds, C22H20N2O4S, (I), and C22H19ClN2O4S, (II), the pyrrolidine rings have twist conformations on the spiro–spiro C—C bonds. In (I), the five-membered ring of the oxindole moiety has an envelope conformation with the spiro C atom as the flap, while in (II) this ring is flat (r.m.s. deviation = 0.042 Å). The mean planes of the pyrrolidine rings are inclined to the mean planes of the indole units [r.m.s deviations = 0.073 and 0.069 Å for (I) and (II), respectively] and the benzothiophene ring systems (r.m.s. deviations = 0.019 and 0.034 Å for (I) and (II), respectively) by 79.57 (8) and 88.61 (7)° for (I), and by 81.99 (10) and 88.79 (10)° for (II). In both compounds, the ethoxycarbonyl group occupies an equatorial position with an extended conformation. The overall conformation of the two molecules differs in the angle of inclination of the indole unit with respect to the benzothiophene ring system, with a dihedral angle between the planes of 71.59 (5) in (I) and 82.27 (7)° in (II). In the crystal of (I), molecules are linkedviapairs of N—H...O hydrogen bonds, forming inversion dimers enclosingR22(14) loops. The dimers are linkedviaC—H...O and bifurcated C—H...O(O) hydrogen bonds, forming sheets lying parallel to (100). In the crystal of (II), molecules are again linkedviapairs of N—H...O hydrogen bonds, forming inversion dimers but enclosing smallerR22(8) loops. Here, the dimers are linked by C—H...O hydrogen bonds, forming ribbons propagating along [010].

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