Substituent Effects in Synthetic Lectins - Exploring the Role of CH−π Interactions in Carbohydrate Recognition

2011 ◽  
Vol 76 (16) ◽  
pp. 6548-6557 ◽  
Author(s):  
Nicholas P. Barwell ◽  
Anthony P. Davis
Keyword(s):  
Substituent Effects ◽  
Carbohydrate Recognition ◽  
Π Interactions

Substituent effects in the so-called cation⋯π interaction of benzene and its boron–nitrogen doped analogues: overlooked role of σ-skeleton

2019 ◽  
Vol 21 (12) ◽  
pp. 6453-6466 ◽  
Author(s):  
Sirous Yourdkhani ◽  
Michał Chojecki ◽  
Tatiana Korona
Keyword(s):  
Substituent Effect ◽  
Substituent Effects ◽  
Interaction Energies ◽  
Nitrogen Doped ◽  
Π Interactions ◽  
Atom Interaction ◽  
Classical Effect ◽  
Boron Nitrogen

By decomposing IQA atom–atom interaction energies to σ and π contributions, we have shown that the substituent effect in cation⋯π interactions is a nonlocal classical effect in which σ-polarization plays an important role.

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.

Role of non-covalent interactions in the supramolecular architectures of mercury(ii) diphenyldithiophosphates: An experimental and theoretical investigation

2021 ◽  
Vol 45 (4) ◽  
pp. 2249-2263
Author(s):  
Pretam Kumar ◽  
Snehasis Banerjee ◽  
Anu Radha ◽  
Tahira Firdoos ◽  
Subash Chandra Sahoo ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Supramolecular Organization ◽  
Π Interactions ◽  
Supramolecular Architectures ◽  
Non Covalent Interactions ◽  
Covalent Interactions

The H-bond, spodium bond and CH⋯π interactions playing an important role in the supramolecular organization of two mercury(ii) diphenyldithiophosphate complexes have been discussed.

The role of cation–π interactions in ethylenic complexes: A theoretical NMR study

2010 ◽  
Vol 493 (1-3) ◽  
pp. 27-32 ◽  
Author(s):  
Ali Ebrahimi ◽  
Mostafa Habibi Khorassani ◽  
Hamid Reza Masoodi
Keyword(s):  
Π Interactions ◽  
Nmr Study

Carbohydrate-Aromatic Interactions: The Role of Curvature on XH···π Interactions

2010 ◽  
Vol 114 (12) ◽  
pp. 4313-4324 ◽  
Author(s):  
R. Mahesh Kumar ◽  
M. Elango ◽  
V. Subramanian
Keyword(s):  
Π Interactions ◽  
Aromatic Interactions

Dual role of silver in a fluorogenic N-squaraine probe based on Ag(I)-π interactions

2021 ◽  
Author(s):  
Manel Vega ◽  
Salvador Blasco ◽  
Enrique García-España ◽  
Bartolome Soberats ◽  
Antonio Frontera ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Evidence ◽  
Dual Role ◽  
Π Interactions ◽  
Turn On

In the presence of Ag(I), the monoanion of a cyano-N-squaraine (I) generates an intense fluorescent turn-on response. Experimental evidence and DFT calculations reveal a sequence of deprotonation-coordination events in which...

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