Microcrystalline solid–solid transformations of conformationally-responsive solvates, desolvates and a salt of N,N′-(1,4-phenylene)dioxalamic acid: the energetics of hydrogen bonding and n/π → π* interactions

CrystEngComm ◽  
2022 ◽  
Author(s):  
Marcos Morales-Santana ◽  
Sayuri Chong-Canto ◽  
José Martín Santiago-Quintana ◽  
Francisco J. Martínez-Martínez ◽  
Efrén V. García-Báez ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Supramolecular Structures ◽  
Π Interactions ◽  
Crystal Network

The supramolecular structures of H2pOx·2S (S = DMSO, DMF, ⅓(MeOH·2W), W) solvates were stablished. The energetics of amide N–H⋯O and n/π → π* interactions maintain the crystal network and the reversibility between polymorphs.

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.

Electrostatics Plus O-π Interactions Rather Than “Directed” Hydrogen Bonding Keep SO42−in a Triangular Pt3Pd3-Tris(2,2′-bipyrazine) Host

2010 ◽  
Vol 16 (19) ◽  
pp. 5577-5580 ◽  
Author(s):  
Anzhela Galstyan ◽  
Pablo J. Sanz Miguel ◽  
Bernhard Lippert
Keyword(s):  
Hydrogen Bonding ◽  
Π Interactions

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.

2D Extended supramolecular structures via π–π interactions of 1D coordination polymers of cadmium(II) complexes of arylazoimidazole using azido and thiocyanato bridging ligands

Polyhedron ◽  
2004 ◽  
Vol 23 (10) ◽  
pp. 1669-1676 ◽  
Author(s):  
Brojogopal Chand ◽  
Umasankar Ray ◽  
Golam Mostafa ◽  
Tian-Huey Lu ◽  
Chittaranjan Sinha
Keyword(s):  
Coordination Polymers ◽  
Supramolecular Structures ◽  
Bridging Ligands ◽  
Π Interactions

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.

scholarly journals 6-Methyl-2-oxo-N-(quinolin-6-yl)-2H-chromene-3-carboxamide: crystal structure and Hirshfeld surface analysis

2016 ◽  
Vol 72 (8) ◽  
pp. 1121-1125
Author(s):  
Lígia R. Gomes ◽  
John Nicolson Low ◽  
André Fonseca ◽  
Maria João Matos ◽  
Fernanda Borges
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Surface Analysis ◽  
Coumarin Derivative ◽  
Hirshfeld Surface ◽  
Supramolecular Structures ◽  
Hirshfeld Surface Analysis ◽  
Quinoline Ring ◽  
Π Interactions

The title coumarin derivative, C20H14N2O3, displays intramolecular N—H...O and weak C—H...O hydrogen bonds, which probably contribute to the approximate planarity of the molecule [dihedral angle between the coumarin and quinoline ring systems = 6.08 (6)°]. The supramolecular structures feature C—H...O hydrogen bonds and π–π interactions, as confirmed by Hirshfeld surface analyses.

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