Browse
Submit Data
Databases
API
Help

Dataset Information

24 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Spectroscopic Evidence for Clusters of Like-Charged Ions in Ionic Liquids Stabilized by Cooperative Hydrogen Bonding.

ABSTRACT: Direct spectroscopic evidence for hydrogen-bonded clusters of like-charged ions is reported for ionic liquids. The measured infrared O-H vibrational bands of the hydroxyethyl groups in the cations can be assigned to the dispersion-corrected DFT calculated frequencies of linear and cyclic clusters. Compensating the like-charge Coulomb repulsion, these cationic clusters can range up to cyclic tetramers resembling molecular clusters of water and alcohols. These ionic clusters are mainly present at low temperature and show strong cooperative effects in hydrogen bonding. DFT-D3 calculations of the pure multiply charged clusters suggest that the attractive hydrogen bonds can compete with repulsive Coulomb forces.

SUBMITTER: Knorr A

PROVIDER: S-EPMC4819523 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Spectroscopic Evidence for Clusters of Like-Charged Ions in Ionic Liquids Stabilized by Cooperative Hydrogen Bonding.

Knorr Anne A Stange Peter P Fumino Koichi K Weinhold Frank F Ludwig Ralf R

Chemphyschem : a European journal of chemical physics and physical chemistry 20160108 4

Direct spectroscopic evidence for hydrogen-bonded clusters of like-charged ions is reported for ionic liquids. The measured infrared O-H vibrational bands of the hydroxyethyl groups in the cations can be assigned to the dispersion-corrected DFT calculated frequencies of linear and cyclic clusters. Compensating the like-charge Coulomb repulsion, these cationic clusters can range up to cyclic tetramers resembling molecular clusters of water and alcohols. These ionic clusters are mainly present at ...[more]

PMID: 26670942

Similar Datasets

Cation-cation clusters in ionic liquids: Cooperative hydrogen bonding overcomes like-charge repulsion.

Project description:Direct spectroscopic evidence for H-bonding between like-charged ions is reported for the ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate. New infrared bands in the OH frequency range appear at low temperatures indicating the formation of H-bonded cation-cation clusters similar to those known for water and alcohols. Supported by DFT calculations, these vibrational bands can be assigned to attractive interaction between the hydroxyl groups of the cations. The repulsive Coulomb interaction is overcome by cooperative hydrogen bonding between ions of like charge. The transition energy from purely cation-anion interacting configurations to those including cation-cation H-bonds is determined to be 3-4 kJmol(-1). The experimental findings and DFT calculations strongly support the concept of anti-electrostatic hydrogen bonds (AEHBs) as recently suggested by Weinhold and Klein. The like-charge configurations are kinetically stabilized with decreasing temperatures.

| S-EPMC4667241 | biostudies-literature

Hydrogen Bonding Between Ions of Like Charge in Ionic Liquids Characterized by NMR Deuteron Quadrupole Coupling Constants-Comparison with Salt Bridges and Molecular Systems.

Project description:We present deuteron quadrupole coupling constants (DQCC) for hydroxyl-functionalized ionic liquids (ILs) in the crystalline or glassy states characterizing two types of hydrogen bonding: The regular Coulomb-enhanced hydrogen bonds between cation and anion (c-a), and the unusual hydrogen bonds between cation and cation (c-c), which are present despite repulsive Coulomb forces. We measure these sensitive probes of hydrogen bonding by means of solid-state NMR spectroscopy. The DQCCs of (c-a) ion pairs and (c-c) H-bonds are compared to those of salt bridges in supramolecular complexes and those present in molecular liquids. At low temperatures, the (c-c) species successfully compete with the (c-a) ion pairs and dominate the cluster populations. Equilibrium constants obtained from molecular-dynamics (MD) simulations show van't Hoff behavior with small transition enthalpies between the differently H-bonded species. We show that cationic-cluster formation prevents these ILs from crystallizing. With cooling, the (c-c) hydrogen bonds persist, resulting in supercooling and glass formation.

| S-EPMC6899581 | biostudies-literature

Molecular Liquids versus Ionic Liquids: The Interplay between Inter-Molecular and Intra-Molecular Hydrogen Bonding as Seen by Vaporisation Thermodynamics.

Project description:In this study, we determined the enthalpies of vaporisation for a suitable set of molecular and ionic liquids using modern techniques for vapour pressure measurements, such as the quartz crystal microbalance, thermogravimetric analysis (TGA), and gas chromatographic methods. This enabled us to measure reasonable vapour pressures, avoiding the problem of the decomposition of the ionic liquids at high temperatures. The enthalpies of vaporisation could be further analysed by applying the well-known "group contribution" methods for molecular liquids and the "centerpiece" method for ionic liquids. This combined approach allowed for the dissection of the enthalpies of vaporisation into different types of molecular interaction, including hydrogen bonding and the dispersion interaction in the liquid phase, without knowing the existing species in both the liquid and gas phases.

| S-EPMC9862684 | biostudies-literature

Cooperative hydrogen bonding in amyloid formation.

Project description:Amyloid diseases, including Alzheimer's and prion diseases, are each associated with unbranched protein fibrils. Each fibril is made of a particular protein, yet they share common properties. One such property is nucleation-dependent fibril growth. Monomers of amyloid-forming proteins can remain in dissolved form for long periods, before rapidly assembly into fibrils. The lag before growth has been attributed to slow kinetics of formation of a nucleus, on which other molecules can deposit to form the fibril. We have explored the energetics of fibril formation, based on the known molecular structure of a fibril-forming peptide from the yeast prion, Sup35, using both classical and quantum (density functional theory) methods. We find that the energetics of fibril formation for the first three layers are cooperative using both methods. This cooperativity is consistent with the observation that formation of amyloid fibrils involves slow nucleation and faster growth.

| S-EPMC2203343 | biostudies-literature

An <i>ab initio</i> Study of the Structure and Energetics of Hydrogen Bonding in Ionic Liquids.

Project description:Unlike typical hydrogen-bonded networks such as water, hydrogen bonded ionic liquids display some unusual characteristics due to the complex interplay of electrostatics, polarization, and dispersion forces in the bulk. Protic ionic liquids in particular contain close-to traditional linear hydrogen bonds that define their physicochemical properties. This work investigates whether hydrogen bonded ionic liquids (HBILs) can be differentiated from aprotic ionic liquids with no linear hydrogen bonds using state-of-the-art ab initio calculations. This is achieved through geometry optimizations of a series of single ion pairs of HBILs in the gas phase and an implicit solvent. Using benchmark CCSD(T)/CBS calculations, the electrostatic and dispersion components of the interaction energy of these systems are compared with those of aprotic ionic liquids. The inclusion of the implicit solvent significantly influenced geometries of single ion pairs, with the gas phase shortening the hydrogen bond to reduce electrostatic interactions. HBILs were found to have stronger interactions by at least 10EtMeNH0 kJ mol-1 over aprotic ILs, clearly highlighting the electrostatic nature of hydrogen bonding. Geometric and energetic parameters were found to complement each other in determining the extent of hydrogen bonding present in these ionic liquids.

| S-EPMC6468050 | biostudies-literature

Thermodynamically Stable Cationic Dimers in Carboxyl-Functionalized Ionic Liquids: The Paradoxical Case of "Anti-Electrostatic" Hydrogen Bonding.

Project description:We show that carboxyl-functionalized ionic liquids (ILs) form doubly hydrogen-bonded cationic dimers (c+=c+) despite the repulsive forces between ions of like charge and competing hydrogen bonds between cation and anion (c+-a-). This structural motif as known for formic acid, the archetype of double hydrogen bridges, is present in the solid state of the IL 1-(carboxymethyl)pyridinium bis(trifluoromethylsulfonyl)imide [HOOC-CH2-py][NTf2]. By means of quantum chemical calculations, we explored different hydrogen-bonded isomers of neutral (HOOC-(CH2)n-py+)2(NTf2-)2, single-charged (HOOC-(CH2)n-py+)2(NTf2-), and double-charged (HOOC- (CH2)n-py+)2 complexes for demonstrating the paradoxical case of "anti-electrostatic" hydrogen bonding (AEHB) between ions of like charge. For the pure doubly hydrogen-bonded cationic dimers (HOOC- (CH2)n-py+)2, we report robust kinetic stability for n = 1-4. At n = 5, hydrogen bonding and dispersion fully compensate for the repulsive Coulomb forces between the cations, allowing for the quantification of the two equivalent hydrogen bonds and dispersion interaction in the order of 58.5 and 11 kJmol-1, respectively. For n = 6-8, we calculated negative free energies for temperatures below 47, 80, and 114 K, respectively. Quantum cluster equilibrium (QCE) theory predicts the equilibria between cationic monomers and dimers by considering the intermolecular interaction between the species, leading to thermodynamic stability at even higher temperatures. We rationalize the H-bond characteristics of the cationic dimers by the natural bond orbital (NBO) approach, emphasizing the strong correlation between NBO-based and spectroscopic descriptors, such as NMR chemical shifts and vibrational frequencies.

| S-EPMC8778807 | biostudies-literature

Hydrogen Bonding as a Clustering Agent in Protic Ionic Liquids: Like-Charge vs Opposite-Charge Dimer Formation.

Project description:The local structure of a series of homologous protic ionic liquids (PILs) is investigated using ab initio computations and ab initio-based molecular dynamics. The purpose of this work is to show that in PILs the network of hydrogen bonds may promote like-charge clustering between anionic species. We correlate the theoretical evidence of this possibility with viscosity experimental data. The homologous series of liquids is obtained by coupling choline with amino acid anions and varying the side chain. We find that the frictional properties of the liquids are clearly connected to the ability of the side chain to establish additional hydrogen bonds (other than the trivial cation-anion interaction). We also show that the large variation of bulk properties along the series of compounds can be explained by assuming that one of the sources of friction in the bulk liquid is the like-charge interaction between anions.

| S-EPMC6645488 | biostudies-literature

Thermophysical Study of Pyridinium-Based Ionic Liquids Sharing Ions.

Project description:The thermophysical properties of three pyridinium-based ionic liquids sharing ions were measured at several temperatures (278.15-338.15) K and at atmospheric pressure (0.1 MPa). Three ionic liquids were studied: 1-butylpyridinium bis(trifluoromethyl-sulfonyl)imide, 1-hexylpyridinium bis(trifluoromethylsulfonyl)imide, and 1-hexylpyridinium tetrafluoroborate. The following thermophysical properties were measured: density, speed of sound, refractive index, surface tension, isobaric molar heat capacity, kinematic viscosity, and electrical conductivity. The thermophysical properties at atmospheric pressure were correlated with temperature, noting that the starting temperature for the speed of sound measurements depended on the ionic liquid. From these experimental results, some derived properties (isentropic compressibility, molar refraction, and dynamic viscosity) are calculated. These results together with those published previously for 1-butylpyridinium tetrafluoroborate are discussed.

| S-EPMC9997080 | biostudies-literature

Hydrogen-Bonding Interactions in Pyridinium-Based Ionic Liquids and Dimethyl Sulfoxide Binary Systems: A Combined Experimental and Computational Study.

Project description:The addition of highly polar and aprotic cosolvents to ionic liquids has proven to considerably decrease the viscosity of the solution and improve mass transfer in many chemical reactions. In this work, the interactions between a representative pyridinium-based ionic liquid, N-butylpyridinium dicyanamide ([Bpy][DCA]), and a cosolvent, dimethylsulfoxide (DMSO), were studied in detail by the combined use of attenuated total reflection Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance (1H NMR), and density functional theory calculations. Several species in the [Bpy][DCA]-DMSO mixtures have been identified, that is, ion clusters can translate into ion pairs during the dilution process. DMSO formed hydrogen bonds (H bonds) simultaneously with [Bpy]+ cations and [DCA]- anions but stronger hydrogen-bonding interactions with the [Bpy]+ cations than the [DCA]- anions, and the intrinsic hydrogen-bond networks of IL were difficult to interrupt at low DMSO concentrations. Interestingly, hydrogen-bonding interactions reach the strongest when the molar fraction of DMSO is 0.4-0.5. Hydrogen-bonding interactions are prominent in the chemical shifts of hydrogen atoms in [Bpy]+ cations, and anisotropy is the main reason for the upfield shifts of DMSO in the presence of [Bpy][DCA]. The theoretical calculations offer in-depth studies of the structural evolution and NMR calculation.

| S-EPMC6641321 | biostudies-literature

Significant enhanced uranyl ions extraction efficiency with phosphoramidate-functionalized ionic liquids via synergistic effect of coordination and hydrogen bond.

Project description:The influence of the linking group between the phosphoryl and bridging moieties in phosphoryl-containing task-specific ionic liquids (TSILs) on the extraction of uranyl ions was experimentally and theoretically investigated. A novel phosphoramidate-based TSIL with an amine group as the linking moiety resulted in a higher uranyl ion extraction efficiency compared with that of other phosphoryl-based TSILs. A distribution ratio of 4999 ± 51 can be achieved for uranyl ions. The uranyl ions (76.7 ± 1.5%) were stripped from the loaded ionic liquid phase in a single stage using 0.05 M diethylenetriamine pentaacetic acid in a 1.0 M guanidine carbonate solution. The extraction stoichiometry of the uranyl ions was determined by a slope analysis of the extraction data. Furthermore, the fundamental nature of the interaction between the phosphoramidate-based TSIL and uranyl ions was theoretically studied for the first time. The theoretical calculations demonstrated that the synergistic effect of the complexation interaction and H-bond formation between the phosphoramidate-functional ionic liquid and uranyl nitrate led to the higher extraction efficiency. These results provide a basis for rational design, synthesis and potential applications of novel TSILs for uranyl extraction.

| S-EPMC5691085 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data