Structural Characterization of 4-Cyanoimidazolium-5-olate, 4,4-Diphenyl-5-imidazolinone, and 4,5-Dicyanoimidazole. A Novel Mesoionic Compound and Decoding of Intermolecular Hydrogen Bonds

1997 ◽  
Vol 62 (20) ◽  
pp. 7037-7043 ◽  
Author(s):  
Ermanno Barni ◽  
Riccardo Bianchi ◽  
Giuliana Gervasio ◽  
Arnold T. Peters ◽  
Guido Viscardi
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Intermolecular Hydrogen Bonds ◽  
Mesoionic Compound

Synthesis and structural characterization of a new self-assembled disulfide linked meso-tetrakis-porphyrin macromolecular array

2008 ◽  
Vol 12 (07) ◽  
pp. 845-848 ◽  
Author(s):  
Abilio J. F. N. Sobral ◽  
Licinia L. G. Justino ◽  
Ana C. C. Santos ◽  
Joana A. Silva ◽  
Cláudia T. Arranja ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Disulfide Bonds ◽  
Metal Coordination ◽  
Intermolecular Hydrogen Bonds ◽  
Coordination Bonding ◽  
Self Assembled

The synthesis of a new self-assembled porphyrin macrostructure based on disulfide bonds, is presented. This constitutes a new way to directly connect porphyrins in macromolecular arrays, to complement the usual methods of intermolecular hydrogen bonds and metal coordination bonding.

4-(Piperidin-1-yl)pyridinium hexafluorophosphate at 150 K

2003 ◽  
Vol 59 (11) ◽  
pp. o622-o624 ◽  
Author(s):  
Bruce D. James ◽  
Siti Mutrofin ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Title Compound ◽  
Ion Pairs ◽  
Piperidine Ring ◽  
Torsion Angles ◽  
Compound C ◽  
Counter Ions

Structural characterization of the title compound, C10H15N2 +·PF6 −, shows it to be ionic, with the pyridine rather than the piperidine N atom being protonated and forming hydrogen bonds to the counter-ions, resulting in two independent ion pairs. A number of unusual features are noted, in particular the remarkably close inter-ring hydrogen contacts [1.97 (3)–2.00 (3) Å] and the considerable differences in the pair of cations, in respect of the torsion angles within the piperidine ring involving the bonds to either side of the N atom.

Synthesis, crystallization, X-ray structural characterization and solid-state assembly of a cyclic hexapeptoid with propargyl and methoxyethyl side chains

2017 ◽  
Vol 73 (3) ◽  
pp. 399-412 ◽  
Author(s):  
Consiglia Tedesco ◽  
Eleonora Macedi ◽  
Alessandra Meli ◽  
Giovanni Pierri ◽  
Giorgio Della Sala ◽  
...  
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Crystal Form ◽  
Side Chains ◽  
Crystal Forms ◽  
Hydrate Crystal ◽  
The Stability ◽  
Efficient Packing

The synthesis and the structural characterization of a cyclic hexapeptoid with four methoxyethyl and two propargyl side chains have disclosed the presence of a hydrate crystal form [form (I)] and an anhydrous crystal form [form (II)]. The relative amounts of form (I) and form (II) in the as-purified product were determined by Rietveld refinement and depend on the purification procedures. In crystal form (I), peptoid molecules assemble in a columnar arrangement by means of side-chain-to-backbone C=CH...OC hydrogen bonds. In the anhydrous crystal form (II), cyclopeptoid molecules form ribbons by means of backbone-to-backbone CH2...OC hydrogen bonds, thus mimicking β-sheet secondary structures in proteins. In both crystal forms side chains act as joints among the columns or the ribbons and contribute to the stability of the whole solid-state assembly. Water molecules in the hydrate crystal form (I) bridge columns of cyclic peptoid molecules, providing a more efficient packing.

Structural Characterization of a Pentapeptide Derived from a Novel Carbohydrate α-Amino Acid

2007 ◽  
Vol 60 (2) ◽  
pp. 93 ◽  
Author(s):  
Adrian Scaffidi ◽  
Brian W. Skelton ◽  
Robert V. Stick ◽  
Allan H. White
Keyword(s):  
Amino Acid ◽  
Synchrotron Radiation ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Internal Hydrogen ◽  
Radiation Study ◽  
Independent Molecules

Subsequent to our previous report describing several novel carbohydrate α-amino acid dipeptides (and the structural characterization of one of those), and their extension to higher peptides, a synchrotron radiation study of one of those—a pentapeptide—showing its structure to be a well-defined helical array in each of two independent molecules, stabilized by internal hydrogen bonds, is reported.

scholarly journals The 7-azanorbornane nucleus of epibatidine: 7-azabicyclo[2.2.1]heptan-7-ium chloride

2017 ◽  
Vol 73 (9) ◽  
pp. 1385-1388 ◽  
Author(s):  
Sergey N. Britvin ◽  
Andrey M. Rumyantsev
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Nicotinic Receptor ◽  
Structural Data ◽  
Chloride Anion ◽  
Mirror Plane ◽  
Poison Frog ◽  
Hydrochloride Salt ◽  
Epipedobates Tricolor

7-Azabicyclo[2.2.1]heptane (7-azanorbornane) is a bridged heterocyclic nucleus found in epibatidine, the alkaloid isolated from the skin of the tropical poison frogEpipedobates tricolor. Since epibatidine is known as one of the most potent acetylcholine nicotinic receptor agonists, a plethora of literature has been devoted to this alkaloid. However, there are no structural data on the unsubstituted 7-azanorbornane, the parent bicyclic ring of epibatidine and its derivatives. We herein present the structural characterization of the 7-azabicyclo[2.2.1]heptane parent ring as its hydrochloride salt, namely 7-azabicyclo[2.2.1]heptan-7-ium chloride, C6H12N+·Cl−. The compete cation is generated by a crystallographic mirror plane with the N atom lying on the mirror, as does the chloride anion. In the crystal, the cations are linked to the anions by N—H...Cl hydrogen bonds, which generate [001] chains.

scholarly journals STRUCTURAL CHARACTERIZATION OF 2-AMINO-2-OXOACETIC ACID BY X-RAY POWDER DIFFRACTION AND QUANTUM CHEMISTRY

2019 ◽  
Vol 16 (33) ◽  
pp. 516-523
Author(s):  
G. E. DELGADO ◽  
L. M. BELANDRIA ◽  
M. GUILLEN ◽  
A.. J. MORA ◽  
L. E. SEIJAS
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Structural Study ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
Structure Determination ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray

2-amino-2-oxoacetic acid, carbamoyl formic acid, or oxamic acid is an active pharmaceutical ingredient (API) of great importance mainly because is an inhibitor of lactic dehydrogenase (LDH). It acts as an inhibitor to the metabolic pathways of the tumor cells and exhibited significant anticancer activity against nasopharyngeal carcinoma (NPC) cells in vitro and can be considered as a potential drug for the treatment of type 2 diabetes. Also, this compound could be used as a building block in the design of supramolecular architectures based on hydrogen bonds through the complimentary hydrogen-bond functionalities of the carbonyl and amide functional groups present. Single-crystal X-ray diffraction is the most powerful technique for crystal structure determination of small molecules. However, for several materials, including oxamic acid, it could be complicated to grow single crystals of suitable size and quality that make them appropriated to structure analysis. For this reason, the structural study was conducted with powder X-ray diffraction which is a process significantly more challenging than structure determination from single-crystal data. Oxamic acid has been characterized by FT-IR and NMR spectroscopic techniques, thermal TGA-DSC analysis, semi-empirical PM7 calculations, and X-ray powder diffraction. The title compound crystallizes in the monoclinic system with space group Cc, Z=4, and unit cell parameters a= 9.4994(4) Å, b= 5.4380(2) Å, c= 6.8636(3) Å, b= 107.149(2)°, V= 338.79(2) Å3. The molecule has a trans conformation. The molecular structure and crystal packing are stabilized mainly by intra- and intermolecular O--H···O and N--H···O hydrogen bonds. The structural characterization of this type of API compound is important to understand its mechanisms of action due to its considerable biological effects. In particular, for oxamic acid, this structural study would allow subsequent examination of its medicinal properties as an antitumor and antidiabetic agent.

scholarly journals Synthesis by self-assembly and structural characterization of a new co-crystal system {[Cu(NO3)2(H2O)2]L1(NO3)2} (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) from copper nitrate and a carbene precursor

2008 ◽  
Vol 6 (4) ◽  
pp. 505-508 ◽  
Author(s):  
Jorge Doimeadios
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Self Assembly ◽  
Three Dimensional ◽  
Building Blocks ◽  
Copper Nitrate ◽  
Supramolecular Network ◽  
Crystal System

AbstractHerein, the first example of a co-crystal system formed by an imidazolium nitrate, a carbene precursor, and copper (II) nitrate, {[Cu(NO3)2(H2O)2]L1(NO3)2} (1) (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) is reported. These two building blocks are connected in the solid state through hydrogen bonds to generate a three-dimensional supramolecular network.

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