Search results for " interaction"
showing 10 items of 5187 documents
Peptide–Membrane Interactions Monitored by Fluorescence Lifetime Imaging: A Study Case of Transportan 10
2021
The interest on detailed analysis of peptide-membrane interactions is of great interest in both fundamental and applied sciences as these may relate to both functional and pathogenic events. Such interactions are highly dynamic and spatially heterogeneous, making the investigation of the associated phenomena highly complex. The specific properties of membranes and peptide structural details, together with environmental conditions, may determine different events at the membrane interface, which will drive the fate of the peptide-membrane system. Here, we use an experimental approach based on the combination of spectroscopy and fluorescence microscopy methods to characterize the interactions …
DLPNO-CCSD(T) scaled methods for the accurate treatment of large supramolecular complexes
2017
In this work, we present scaled variants of the DLPNO-CCSD(T) method, dubbed as (LS)DLPNO-CCSD(T) and (NS)DLPNO-CCSD(T), to obtain accurate interaction energies in supramolecular complexes governed by noncovalent interactions. The novel scaled schemes are based on the linear combination of the DLPNO-CCSD(T) correlation energies calculated with the standard (LoosePNO and NormalPNO) and modified (Loose2PNO and Normal2PNO) DLPNO-CCSD(T) accuracy levels. The scaled DLPNO-CCSD(T) variants provide nearly TightPNO accuracy, which is essential for the quantification of weak noncovalent interactions, with a noticeable saving in computational cost. Importantly, the accuracy of the proposed schemes is…
Understanding the affinity of bis-exTTF macrocyclic receptors towards fullerene recognition
2019
A new series of fullerene receptors based on exTTF macrocycles with alkyl ether chains of increasing length is reported. The novel macrocyclic receptors are able to favourably interact with fullerene C60 through a synergistic combination of π–π, CH⋯π and n⋯π noncovalent interactions. We identify that the highest affinity towards C60 recognition is achieved for the host with the tightest fit; that is, the smallest receptor with a cavity large enough to host the buckyball inside (log Ka = 5.2 in chlorobenzene at 298 K). However, besides this expected observation, theoretical calculations evidence that the most stable self-assembling configuration corresponds for all the receptors to an outsid…
(1-Adamantyl)methyl glycidyl ether: a versatile building block for living polymerization.
2014
(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST). Additionally, AdaGE is utilized as a termination agent in carbanionic polymerization, affording adamantyl-terminated polymers. Using these structures as macroinitiators fo…
Supramolecular Assembly of Metal Complexes by (Aryl)I⋅⋅⋅d[PtII] Halogen Bonds
2020
The theoretical data for the half-lantern complexes [{Pt( CN^ )(μ- SN^ )}2 ] [1-3; CN^ is cyclometalated 2-Ph-benzothiazole; SN^ is 2-SH-pyridine (1), 2-SH-benzoxazole (2), 2-SH-tetrafluorobenzothiazole (3)] indicate that the Pt⋅⋅⋅Pt orbital interaction increases the nucleophilicity of the outer d z2 orbitals to provide assembly with electrophilic species. Complexes 1-3 were co-crystallized with bifunctional halogen bonding (XB) donors to give adducts (1-3)2 ⋅(1,4-diiodotetrafluorobenzene) and infinite polymeric [1⋅1,1'-diiodoperfluorodiphenyl]n . X-ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I⋅⋅⋅d z2 [PtII ] XBs between iodine σ-holes and lone pa…
Host–Guest Chemistry: Oxoanion Recognition Based on Combined Charge‐Assisted C−H or Halogen‐Bonding Interactions and Anion⋅⋅⋅Anion Interactions Media…
2016
Several bis-triazolium-based receptors have been synthesized and their anion-recognition capabilities have been studied. The central chiral 1,1'-bi-2-naphthol (BINOL) core features either two aryl or ferrocenyl end-capped side arms with central halogen- or hydrogen-bonding triazolium receptors. NMR spectroscopic data indicate the simultaneous occurrence of several charge-assisted aliphatic and heteroaromatic C-H noncovalent interactions and combinations of C-H hydrogen and halogen bonding. The receptors are able to selectively interact with HP2 O7 (3-) , H2 PO4 (-) , and SO4 (2-) anions, and the value of the association constant follows the sequence: HP2 O7 (3-) >SO4 (2-) >H2 PO4 (-) . The …
Properties and interactions – melting point of tribromobenzene isomers
2021
The melting points of tribromobenzene isomers are correlated with the number, nature and distribution of intermolecular interactions in their structures.
The geometry of the silver 1,1′-dibenzyl-2,2′-biimidazole complexes
2013
Abstract The argentophilic interactions and interactions of weakly coordinated nitrate and water with silver metal were studied by investigating the reaction of 1,1′-dibenzyl-2,2′-biimidazole (Bn2bim) with silver nitrate. Three new silver complexes [Ag4(Bn2bim)4(NO3)2]·4(CH3CH2OH)·2(NO3)·0.5(H2O) (1), [Ag4(Bn2bim)4(H2O)4]·4(NO3) (2) and [Ag4(Bn2bim)4(NO3)4]·6(CH2Cl2)·2(H2O) (3) were synthesized and characterized. Complexes 1-3 have rare tetranuclear twisted closed cyclic structure with four bridging biimidazoles and variable nitrate/water ratio. The interactions between the nitrate ligand and Ag as well as water ligands and Ag are considered to be weak due to the ease of exchanging them. Th…
The Synergetic Interplay of Weak Interactions in the Ion-Pair Recognition of Quaternary and Diquaternary Ammonium Salts by Halogenated Resorcinarenes
2013
The influence of halogens on the noncovalent interactions of different upper-rim-substituted hexylresorcinarenes with quaternary and diquaternary ammonium iodide salts was investigated in the gas phase by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry and in solution by 1H NMR titration studies. The electronic nature of the substituents on the upper rim of the resorcinarene was directly reflected in the order of binding strengths of the hosts towards quaternary and diquaternary ammonium cations in the gas phase. In solution, the opposite trend was observed, with generally higher binding constants for the diquaternary over the quaternary salts…
Competing salt effects on phase behavior of protein solutions: tailoring of protein interaction by the binding of multivalent ions and charge screeni…
2014
The phase behavior of protein solutions is affected by additives such as crowder molecules or salts. In particular, upon addition of multivalent counterions, a reentrant condensation can occur; i.e., protein solutions are stable for low and high multivalent ion concentrations but aggregating at intermediate salt concentrations. The addition of monovalent ions shifts the phase boundaries to higher multivalent ion concentrations. This effect is found to be reflected in the protein interactions, as accessed via small-angle X-ray scattering. Two simulation schemes (a Monte Carlo sampling of the counterion binding configurations using the detailed protein structure and an analytical coarse-grain…