Structure–Performance Relationship in Thermally Stable Energetic Materials: Tunable Physical Properties of Benzopyridotetraazapentalene by Incorporating Amino Groups, Hydrogen Bonding, and π–π Interactions

2020 ◽  
Vol 20 (3) ◽  
pp. 2106-2114 ◽  
Author(s):  
Wen-Jing Geng ◽  
Qing Ma ◽  
Ya Chen ◽  
Wei Yang ◽  
Yun-Fei Jia ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Physical Properties ◽  
Energetic Materials ◽  
Thermally Stable ◽  
Amino Groups ◽  
Π Interactions

The Action of Thrombin on Modified Fibrinogen

1983 ◽  
Vol 49 (03) ◽  
pp. 208-213
Author(s):  
A J Osbahr
Keyword(s):  
Physical Properties ◽  
Negative Charge ◽  
Lysine Residue ◽  
Fibrinopeptide A ◽  
Amino Groups ◽  
Lysine Residues ◽  
Citraconic Anhydride

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

Theoretical ab initio study of substituted benzene trimer: Interplay between hydrogen bonding and π–π interactions

2011 ◽  
Vol 975 (1-3) ◽  
pp. 106-110 ◽  
Author(s):  
Carolina Estarellas ◽  
Antonio Frontera ◽  
David Quiñonero ◽  
Pere M. Deyà
Keyword(s):  
Hydrogen Bonding ◽  
Ab Initio ◽  
Ab Initio Study ◽  
Π Interactions

(Acetylacetonato-κ2O,O′)[1-(4-bromophenyl-κC2)-3-methylimidazol-2-ylidene-κC2]platinum(II)

2012 ◽  
Vol 68 (8) ◽  
pp. m203-m205 ◽  
Author(s):  
Mario Tenne ◽  
Yvonne Unger ◽  
Thomas Strassner
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Intermolecular Hydrogen Bonding ◽  
Coordination Environment ◽  
Π Interactions ◽  
New Class ◽  
Square Planar ◽  
Parallel Fashion

The title platinum(II) complex, [Pt(C10H8BrN2)(C5H7O2)], has a bidentate cyclometallated phenylimidazolylidene ligand and an acetylacetonate spectator ligand, which form a distorted square-planar coordination environment around the PtIIcentre. In the solid state, the molecules are oriented in a parallel fashion by intermolecular hydrogen bonding and π–π and C—H...π interactions, while close Pt...Pt contacts are not observed. The structure is only the second example for this new class of compounds.

Fluoride-Selective Host Based on Anion–π Interactions, Ion Pairing, and Hydrogen Bonding: Synthesis and Fluoride-Ion Sandwich Complex

2007 ◽  
Vol 119 (46) ◽  
pp. 8938-8940 ◽  
Author(s):  
Mark Mascal ◽  
Ilya Yakovlev ◽  
Edward B. Nikitin ◽  
James C. Fettinger
Keyword(s):  
Hydrogen Bonding ◽  
Ion Pairing ◽  
Fluoride Ion ◽  
Sandwich Complex ◽  
Π Interactions

Hydrogen-bonding networks of purine derivatives and their bilayers for guest intercalation

CrystEngComm ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 62-67
Author(s):  
Yoona Jang ◽  
Seo Yeon Yoo ◽  
Hye Rin Gu ◽  
Yu Jin Lee ◽  
Young Shin Cha ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Two Dimensional ◽  
Purine Derivatives ◽  
Guest Molecules ◽  
Π Interactions ◽  
Hydrogen Bonding Networks ◽  
Hydrogen Bonded

6-Chloro-9-propyl-purin-2-amine (pr-GCl) forms two-dimensional hydrogen-bonded networks which in turn stack via π–π interactions, leading to the formation of bilayers that can accommodate organic guest molecules.

Hydrogen-bonding patterns in bis[2,4,6-triazaniumylcyclohexane-1,3,5-tris(olate)-κ3O,O′,O′′]germanium(IV) tetrachloride hexahydrate

2016 ◽  
Vol 72 (1) ◽  
pp. 28-34
Author(s):  
Christian Neis ◽  
Bernd Morgenstern ◽  
Kaspar Hegetschweiler
Keyword(s):  
Hydrogen Bonding ◽  
Hydration Shell ◽  
Chloride Ions ◽  
Three Dimensions ◽  
Water Molecules ◽  
Amino Groups ◽  
Compound C ◽  
Hydrated Salt ◽  
Phd Thesis ◽  
Hydroxy Groups

A first preliminary report on the crystal structure of a hydrated salt formulated as [Ge(taci)2]Cl4·13H2O (taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol) appeared more than 20 years ago [Ghisletta (1994). PhD thesis, ETH Zürich. Switzerland]. At that time it was not possible to discriminate unambiguously between the positions of some of the chloride ions and water O atoms, and disorder was thus postulated. In a new determination, a conclusive scheme of hydrogen bonding proves to be a particularly appealing aspect of the structure. Single crystals of the title compound, C12H30GeN6O64+·4Cl−·6H2O or [Ge(taci)2]2Cl8·12H2O, were grown from an aqueous solution by slow evaporation of the solvent. The two [Ge(taci)2]4+cations exhibit a double-adamantane-type structure with exclusive O-atom coordination and approximateD3dsymmetry. The taci ligands adopt a zwitterionic form with deprotonated hydroxy groups and protonated amino groups. Both cations are hydrogen bonded to six water molecules. The structure of the hydration shell of the two cations is, however, slightly different. The {[Ge(taci)2]·6H2O}4+aggregates are interlinked in all three dimensions by further hydrogen bonds of the types N—H...Cl...H—N, N—H...O(H)2...H—N, (Ge)O...H—O(H)...H—N, N—H...O(H)—H...Cl...H—N, (Ge)O...H—O—H...Cl...H—N, N—H...O(H)—H...Cl...H—(H)O...H—N, (Ge)O...H—O—H...Cl...H—(H)O...H—N and Ge(O)...H—O—H...Cl...H—O—H...O(Ge).

β-Amino ketoximes: a study of basicity, hydrogen bonding and isomerism

1977 ◽  
Vol 30 (7) ◽  
pp. 1467 ◽  
Author(s):  
HK Powell ◽  
JM Russell
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Calorimetric Data ◽  
Amino Groups ◽  
Or Groups ◽  
Inductive Effects ◽  
Methylene Groups ◽  
Secondary Amino ◽  
Intramolecular Hydrogen ◽  
Cis And Trans

The protonation reactions of the diamine dioxime 4,4,9,9-tetramethyl- 5,8-diazadodecane-2,11-dione dioxime and its O-methyl and bis-O-methyl ethers have been studied at 25�, I 0.10 M NaCl. The (substituted) oxime groups cause a marked reduction in the basicity of the secondary amino groups. log K (potentiometric) and ΔH (calorimetric) data are interpreted in terms of inductive effects of the oxime group and possible intramolecular hydrogen bonding, N+-H...N(OR)=, pKa for methoxy-amine, NH2OMe, has been determined (4.62�0.01, I 0.10 M NaCl, 25�). ������ P.m.r. spectra are assigned for β-amino ketoximes having α- methyl and α-methylene groups cis and trans to =N-OR groups. Infrared spectra are reported.

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