The role of cation⋯π interactions in capsule formation: co-crystals of resorcinarenes and alkyl ammonium salts

CrystEngComm ◽  
2008 ◽  
Vol 10 (12) ◽  
pp. 1803 ◽  
Author(s):  
Sara Busi ◽  
Heidi Saxell ◽  
Roland Fröhlich ◽  
Kari Rissanen
Keyword(s):  
Ammonium Salts ◽  
Capsule Formation ◽  
Π Interactions ◽  
Alkyl Ammonium

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

scholarly journals Crystal structures of three newN-halomethylated quaternary ammonium salts

2015 ◽  
Vol 71 (10) ◽  
pp. 1230-1235
Author(s):  
Carolina Múnera-Orozco ◽  
Rogelio Ocampo-Cardona ◽  
David L. Cedeño ◽  
Rubén A. Toscano ◽  
Luz Amalia Ríos-Vásquez
Keyword(s):  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Compound I ◽  
Nlo Properties ◽  
Π Interactions

In the crystals of the titleN-halomethylated quaternary ammonium salts, C19H23IN+·I−, (I) [systematic name:N-(4,4-diphenylbut-3-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], C20H25IN+·I−, (II) [systematic name:N-(5,5-diphenylpent-4-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], and C21H27IN+·I−, (III) [systematic name:N-(6,6-diphenylhex-5-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], there are short I...I−interactions of 3.564 (4), 3.506 (1) and 3.557 (1) Å for compounds (I), (II) and (III), respectively. Compound (I) crystallizes in the Sohncke groupP21as an `enantiopure' compound and is therefore a potential material for NLO properties. In the crystal of compound (I), molecules are linked by C—H...I−and C—H...π interactions which, together with the I...I−interactions, lead to the formation of ribbons along [100]. In (II), there are only C—H...I−interactions which, together with the I...I−interactions, lead to the formation of helices along [010]. In (III), apart from the I...I−interactions, there are no significant intermolecular interactions present.

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...

The Role of the Peripheral Anionic Site and Cation−π Interactions in the Ligand Penetration of the Human AChE Gorge

2005 ◽  
Vol 127 (25) ◽  
pp. 9147-9155 ◽  
Author(s):  
Davide Branduardi ◽  
Francesco Luigi Gervasio ◽  
Andrea Cavalli ◽  
Maurizio Recanatini ◽  
Michele Parrinello
Keyword(s):  
Anionic Site ◽  
Π Interactions

scholarly journals Role of Surfactants in the Properties of Poly(Ethylene Terephthalate)/Purified Clay Nanocomposites

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1397 ◽  
Author(s):  
Elaine dos Santos ◽  
Marcus Fook ◽  
Oscar Malta ◽  
Suédina de Lima Silva ◽  
Itamara Leite
Keyword(s):  
Clay Nanocomposites ◽  
Phosphonium Salts ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Alkyl Ammonium ◽  
Pet Crystallization

Purified clay was modified with different amounts of alkyl ammonium and phosphonium salts and used as filler in the preparation of PET nanocomposites via melt intercalation. The effect of this type of filler on morphology and thermal and mechanical properties of PET nanocomposites was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile properties, and transmission electron microscopy (TEM). The results showed that the mixture of alkyl ammonium and phosphonium salts favored the production of PET nanocomposites with intercalated and partially exfoliated morphologies with slight improvement in thermal stability. In addition, the incorporation of these organoclays tended to inhibit PET crystallization behavior, which is profitable in the production of transparent bottles.

Epithelial—mesenchymal tissue interactions guiding otic capsule formation: the role of the otocyst

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 1-24
Author(s):  
Joseph R. McPhee ◽  
Thomas R. Van De Water
Keyword(s):  
Mouse Embryo ◽  
Mouse Embryos ◽  
In Vitro Studies ◽  
Otic Capsule ◽  
Membranous Labyrinth ◽  
Capsule Formation ◽  
Tissue Interactions ◽  
Mesenchymal Tissue

The otocyst is the epithelial anlage of the membranous labyrinth which interacts with surrounding cephalic mesenchyme to form an otic capsule. A series of in vitro studies was performed to gain a better understanding of the epithelial—mesenchymal interactions involved in this process. Parallel series of otocyst/mesenchyme (O/M) and isolated periotic mesenchyme (M) explants provided morphological and biochemical data to define the role of the otocyst in organizing and directing formation of its cartilaginous otic capsule. Explants were made from mouse embryos ranging in age from 10 to 14 days of gestation, and organ cultured under identical conditions until the chronological equivalent of 16 days of gestation. Expression of chrondrogenesis was determined by both histology and biochemistry. The in vitro behaviour of periotic mesenchyme explanted either with or without an otocyst supports several hypotheses that explain aspects of otic capsule development. The results indicate that (a) prior to embryonic day 12 the otocyst alone is not sufficient to stimulate chondrogenesis of the otic capsule within O/M explants; (b) the otocyst acts as an inductor of capsule chondrogenesis within O/M explants between embryonic days 12 to 13; (c) isolated mesenchyme within M explants taken from 13-day-old embryos are capable of initiating in vitro chondrogenesis, but without expressing capsule morphology in the absence of the otocyst; and (d) the isolated mesenchyme of M explants obtained from 14-day-old embryos expresses both chondrogenesis and otic capsule morphology in the absence of the otocyst. These findings suggest that the otocyst acts as an inductor of chondrogenesis of periotic mesenchyme tissue between embryonic days 11 to 13, and controls capsular morphogenesis between embryonic days 13 to 14 in the mouse embryo.

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