scholarly journals Host–guest modes and supramolecular frameworks of complexes of tetramethyl cucurbit[6]uril with 4-chloroaniline and 4,4′-diaminostilbene

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3470-3475
Author(s):  
Ye Meng ◽  
Weiwei Zhao ◽  
Jun Zheng ◽  
Daofa Jiang ◽  
Jie Gao ◽  
...  

Two TMeQ[6]-based multi-dimensional supramolecular frameworks were formed driven by weak interaction forces in the system (hydrogen bonding, C–H... π interactions, ion–dipole interactions, and dipole–dipole interactions).

2007 ◽  
Vol 79 (6) ◽  
pp. 1057-1075 ◽  
Author(s):  
N. Jiten Singh ◽  
Han Myoung Lee ◽  
Seung Bum Suh ◽  
Kwang S. Kim

For the design of functional molecules and nanodevices, it is very useful to utilize nanorecognition (which is governed mainly by interaction forces such as hydrogen bonding, ionic interaction, π-H/π-π interactions, and metallic interactions) and nanodynamics (involving capture, transport, and release of electrons, photons, or protons). The manifestation of these interaction forces has led us to the design and realization of diverse ionophores/receptors, organic nanotubes, nanowires, molecular mechanical devices, molecular switches, enzyme mimetics, protein folding/unfolding, etc. In this review, we begin with a brief discussion of the interaction forces, followed by some of our representative applications. We discuss ionophores with chemo-sensing capability for biologically important cations and anions and explain how the understanding of hydrogen bonding and π-interactions has led to the design of self-assembled nanotubes from calix[4]hydroquinone (CHQ). The binding study of neutral and cationic transition metals with the redox system of hydroquinone (HQ) and quinone (Q) predicts what kind of nanostructures would form. Finally, we look into the conformational changes between stacked and edge-to-face conformers in π-benzoquinone-benzene complexes controlled by alternating electrochemical potential. The resulting flapping motion illustrates a promising pathway toward the design of mobile nanomechanical devices.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon

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.


2011 ◽  
Vol 975 (1-3) ◽  
pp. 106-110 ◽  
Author(s):  
Carolina Estarellas ◽  
Antonio Frontera ◽  
David Quiñonero ◽  
Pere M. Deyà

2012 ◽  
Vol 68 (8) ◽  
pp. m203-m205 ◽  
Author(s):  
Mario Tenne ◽  
Yvonne Unger ◽  
Thomas Strassner

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.


2007 ◽  
Vol 119 (46) ◽  
pp. 8938-8940 ◽  
Author(s):  
Mark Mascal ◽  
Ilya Yakovlev ◽  
Edward B. Nikitin ◽  
James C. Fettinger

CrystEngComm ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 62-67
Author(s):  
Yoona Jang ◽  
Seo Yeon Yoo ◽  
Hye Rin Gu ◽  
Yu Jin Lee ◽  
Young Shin Cha ◽  
...  

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.


2016 ◽  
Vol 18 (23) ◽  
pp. 15980-15987 ◽  
Author(s):  
Fabrizio Lo Celso ◽  
Bachir Aoun ◽  
Alessandro Triolo ◽  
Olga Russina

Liquid DBSO shows mesoscopic polar/apolar alternation. Dipole–dipole interactions are responsible for correlations between DBSO molecules that do not interact through hydrogen bonding.


2019 ◽  
Vol 75 (6) ◽  
pp. 806-811
Author(s):  
Jia Wang ◽  
Tianchao You ◽  
Teng Wang ◽  
Qikui Liu ◽  
Jianping Ma ◽  
...  

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.


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