scholarly journals A Highly Efficient Neutral Anion Receptor in Polar Environments by Synergy of Anion−π Interactions and Hydrogen Bonding

2021 ◽  
Author(s):  
Marta Queizán ◽  
Marta Sánchez-Lozano ◽  
Marcos Mandado ◽  
Jose M. Hermida-Ramón
Keyword(s):  
Hydrogen Bonding ◽  
Anion Receptor ◽  
Π Interactions ◽  
Highly Efficient

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

A new tripodal anion receptor with CH···X− hydrogen bonding

1999 ◽  
Vol 40 (28) ◽  
pp. 5219-5222 ◽  
Author(s):  
Kiyoshi Sato ◽  
Sadao Arai ◽  
Takamichi Yamagishi
Keyword(s):  
Hydrogen Bonding ◽  
Anion Receptor

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.

Synthesis of 7-Pentafluorophenyl-1H-indole: An Anion Receptor for Anion–π Interactions

Synlett ◽  
2014 ◽  
Vol 25 (14) ◽  
pp. 2075-2077 ◽  
Author(s):  
Markus Albrecht ◽  
Zhan-Hu Sun ◽  
Michael Giese ◽  
Fangfang Pan ◽  
Kari Rissanen
Keyword(s):  
Anion Receptor ◽  
Π Interactions

Adsorption behaviour of a CdII–triazole MOF for butan-2-one in a single-crystal-to-single-crystal (SCSC) fashion: the role of hydrogen bonding and C—H...π interactions

2019 ◽  
Vol 75 (6) ◽  
pp. 806-811
Author(s):  
Jia Wang ◽  
Tianchao You ◽  
Teng Wang ◽  
Qikui Liu ◽  
Jianping Ma ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Single Crystal ◽  
Specific Binding ◽  
Supramolecular Interactions ◽  
Adsorption Behaviour ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Π Interactions ◽  
H Nmr

The adsorption behaviour of the CdII–MOF {[Cd(L)2(ClO4)2]·H2O (1), where L is 4-amino-3,5-bis[3-(pyridin-4-yl)phenyl]-1,2,4-triazole, for butan-2-one was investigated in a single-crystal-to-single-crystal (SCSC) fashion. A new host–guest system that encapsulated butan-2-one molecules, namely poly[[bis{μ3-4-amino-3,5-bis[3-(pyridin-4-yl)phenyl]-1,2,4-triazole}cadmium(II)] bis(perchlorate) butanone sesquisolvate], {[Cd(C24H18N6)2](ClO4)2·1.5C4H8O} n , denoted C4H8O@Cd-MOF (2), was obtained via an SCSC transformation. MOF 2 crystallizes in the tetragonal space group P43212. The specific binding sites for butan-2-one in the host were determined by single-crystal X-ray diffraction studies. N—H...O and C—H...O hydrogen-bonding interactions and C—H...π interactions between the framework, ClO4 − anions and guest molecules co-operatively bind 1.5 butan-2-one molecules within the channels. The adsorption behaviour was further evidenced by 1H NMR, IR, TGA and powder X-ray diffraction experiments, which are consistent with the single-crystal X-ray analysis. A 1H NMR experiment demonstrates that the supramolecular interactions between the framework, ClO4 − anions and guest molecules in MOF 2 lead to a high butan-2-one uptake in the channel.

Synthesis of 1,2-Diamine Bifunctional Catalysts for the Direct Aldol Reaction Through Probing the Remote Amide Hydrogen

2019 ◽  
Vol 6 (2) ◽  
pp. 171-176
Author(s):  
Rajasekhar Dodda ◽  
Sampak Samanta ◽  
Matthew Su ◽  
John Cong-Gui Zhao
Keyword(s):  
Hydrogen Bonding ◽  
Catalytic Activity ◽  
Aldol Reaction ◽  
Catalytic Efficiency ◽  
Aldol Reactions ◽  
Catalyst Loading ◽  
Bifunctional Catalysts ◽  
Amide Hydrogen ◽  
Highly Efficient ◽  
Direct Aldol Reaction

Background: While proline can catalyze the asymmetric direct aldol reactions, its catalytic activity and catalyst turnover are both low. To improve the catalytic efficiency, many prolinebased organocatalysts have been developed. In this regard, prolinamide-based bifunctional catalysts have been demonstrated by us and others to be highly efficient catalysts for the direct aldol reactions. Results: Using the β-acetamido- and β-tosylamidoprolinamide catalysts, the highly enantio- and diastereoselective direct aldol reactions between enolizable ketones and aldehydes were achieved (up to >99% ee, 98:2 dr). A low catalyst loading of only 2-5 mol % of the β-tosylamidoprolinamide catalyst was needed to obtain the desired aldol products in good to high yields and high stereoselectivities. Methods: By carefully adjusting the hydrogen bonding ability of the remote β-amide hydrogen of the 1,2-diamine-based prolinamide bifunctional catalysts, the catalytic activity and the asymmetric induction of these catalysts were significantly improved for the direct aldol reaction between aldehydes and enolizable ketones. Conclusion: Some highly efficient 1,2-diamine-based bifunctional prolinamide catalysts have been developed through probing the remote β-amide hydrogen for its hydrogen bonding capability. These catalysts are easy to synthesize and high enantioselectivities may be achieved at very low catalyst loadings.

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