scholarly journals Analyzing carboxylic acid and amine-nitro hydrogen-bond geometry in the cocrystal of 4-aminobenzoic acid and 3,5-dinitrobenzoic acid by use of 298 K X-ray and 15 K neutron diffraction

1993 ◽  
Author(s):  
G.M. Frankenbach ◽  
M.C. Etter ◽  
A.J. Schultz ◽  
J.M. Williams
CrystEngComm ◽  
2014 ◽  
Vol 16 (35) ◽  
pp. 8177-8184 ◽  
Author(s):  
Andrew O. F. Jones ◽  
Charlotte K. Leech ◽  
Garry J. McIntyre ◽  
Chick C. Wilson ◽  
Lynne H. Thomas

The persistence of the acid⋯amide heterodimer and the effect of methyl substitution on the short strong O–H⋯O hydrogen bond is investigated in urea and methylurea di-carboxylic acid molecular complexes. Temperature dependent structural changes are also reported utilising X-ray and neutron diffraction in tandem.


2001 ◽  
Vol 123 (32) ◽  
pp. 7898-7906 ◽  
Author(s):  
Concepción Foces-Foces ◽  
Aurea Echevarría ◽  
Nadine Jagerovic ◽  
Ibon Alkorta ◽  
José Elguero ◽  
...  

2015 ◽  
Vol 71 (2) ◽  
pp. 152-154 ◽  
Author(s):  
Di-Chang Zhong ◽  
Hua-Bin Guo ◽  
Ji-Hua Deng ◽  
Ping Lian ◽  
Xu-Zhong Luo

Single-crystal X-ray diffraction analysis of poly[bis(μ2-5-carboxy-2-propyl-1H-imidazole-4-carboxylato-κ3N3,O4:O5)copper(II)], [Cu(C8H9N2O4)2)]n, indicates that one carboxylic acid group of the 2-propyl-1H-imidazole-4,5-dicarboxylic acid (H3PDI) ligand is deprotonated. The resulting H2PDI−anion, acting as a bridge, connects the CuIIcations to form a two-dimensional (4,4)-connected layer. Adjacent layers are further linked through interlayer hydrogen-bond interactions, resulting in a three-dimensional supramolecular structure.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hui-Jing Li ◽  
Jun-Li Wang ◽  
Rui Wang ◽  
Dong-Hui Luo ◽  
Yan-Chao Wu

4H-Chromene-2-carboxylic acid ester derivatives of renieramycin M might be of use for the structural-activity relationship studies of antitumor antibiotic tetrahydroisoquinoline natural products. Accordingly, 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic acid, one key intermediate, was synthesized via the condensation of (3E)-2-oxo-4-phenylbut-3-enoate methyl ester with 4-tert-butylphenol in the presence of AuCl3/3AgOTf (5 mol%), followed by cyclodehydration and aqueous hydrolysis. The product was unambiguously shown to the 4H-chromene-2-carboxylic acid by spectroscopy and X-ray crystallographic analysis. A packing diagram of the crystal structure shows that aromaticπ-stacking interactions and O–H⋯O hydrogen bond stabilize the structure in the solid.


2011 ◽  
Vol 67 (6) ◽  
pp. 552-559 ◽  
Author(s):  
Mihaela-Diana Şerb ◽  
Ruimin Wang ◽  
Martin Meven ◽  
Ulli Englert

N,N-Dimethylbiguanidinium bis(hydrogensquarate) features an impressive range of hydrogen bonds within the same crystal structure: neighbouring anions aggregate to a dianionic pair through two strong O—H...O interactions; one of these can be classified among the shortest hydrogen bonds ever studied. Cations and anions in this organic salt further interact via conventional N—H...O and nonclassical C—H...O contacts to an extended structure. As all these interactions occur in the same sample, the title compound is particularly suitable to monitor even subtle trends in hydrogen bonds. Neutron and high-resolution X-ray diffraction experiments have enabled us to determine the electron density precisely and to address its properties with an emphasis on the nature of the X—H...O interactions. Sensitive criteria such as the Laplacian of the electron density and energy densities in the bond-critical points reveal the incipient covalent character of the shortest O—H...O bond. These findings are in agreement with the precise geometry from neutron diffraction: the shortest hydrogen bond is also significantly more symmetric than the longer interactions.


2015 ◽  
Vol 71 (2) ◽  
pp. o125-o126 ◽  
Author(s):  
M. Krishna Kumar ◽  
P. Pandi ◽  
S. Sudhahar ◽  
G. Chakkaravarthi ◽  
R. Mohan Kumar

In the title 1:1 adduct, C6H7N·C7H7NO2, the carboxylic acid group is twisted at an angle of 4.32 (18)° with respect to the attached benzene ring. In the crystal, the carboxylic acid group is linked to the pyridine ring by an O—H...N hydrogen bond, forming a dimer. The dimers are linked by N—H...O hydrogen bonds, generating (010) sheets.


2007 ◽  
Vol 63 (3) ◽  
pp. 497-504 ◽  
Author(s):  
R. Chitra ◽  
R. R Choudhury

Single-crystal neutron diffraction investigation of bis(glycinium) oxalate was undertaken in order to study its hydrogen-bonding network, particularly the very short hydrogen bond between the glycinum and oxalate ions, indicated by the X-ray diffraction study. The non-existence of any phase transition in these crystals was attributed to the fact that the short hydrogen bond in bis(glycinium) oxalate is asymmetric in nature, with no hydrogen disorder. The potential energy landscape for the above-mentioned H atom was found to have a single minimum closer to the glycinium ion. IR and Raman investigations of the title complex supported the above result.


Author(s):  
Kalina Mambourg ◽  
Nikolay Tumanov ◽  
Gilles Henon ◽  
Steve Lanners ◽  
Javier Garcia-Ladona ◽  
...  

The structure of ethyl 1-[N-(4-methylphenyl)-N-(methylsulfonyl)alanyl]piperidine-4-carboxylate, C19H28N2O5S, I, a compound of interest as activator of Ubiquitin C-terminal Hydrolase-L1 (UCH-L1), was determined by single-crystal X-ray diffraction (SCXRD) analysis. In order to find new activators, a derivative of compound I, namely, 1-[N-(4-methylphenyl)-N-(methylsulfonyl)alanyl]piperidine-4-carboxylic acid, C17H24N2O5S, II, was studied. The synthesis and crystal structure are also reported. Despite being analogues, different crystal packings are observed. Compound II bears a carboxylic group, which favors a strong hydrogen bond. A polymorph risk assessment was carried out to study interactions in compound II.


2005 ◽  
Vol 61 (6) ◽  
pp. 724-730 ◽  
Author(s):  
John. A. Cowan ◽  
Judith A. K. Howard ◽  
Garry, J. McIntyre ◽  
Samuel M.-F Lo ◽  
Ian D. Williams

Pyridine-3,5-dicarboxylic acid has been studied by single-crystal neutron diffraction at 15 and 296 K. Pyridine-3,5-dicarboxylic acid, in which the carboxylic acid protons have been replaced by deuterons, has also been studied at 15, 150 and 296 K. The protonated structure contains a short N...H...O hydrogen bond [N...O 2.523 (2) Å at 15 K]. Temperature-dependent proton migration occurs where the N—H distance in the hydrogen bond changes from 1.213 (4) Å at 15 K to 1.308 (6) Å at 300 K. In the deuterated structure the overall hydrogen-bond length increased [N...O 2.538 (3) Å at 15 K] and the magnitude of the migration increased so that the N—D distance changes from 1.151 (3) Å at 15 K to 1.457 (4) Å at 300 K.


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