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

2019 ◽  
Vol 58 (49) ◽  
pp. 17863-17871 ◽  
Author(s):  
Alexander E. Khudozhitkov ◽  
Jan Neumann ◽  
Thomas Niemann ◽  
Dzmitry Zaitsau ◽  
Peter Stange ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Liquids ◽  
Coupling Constants ◽  
Salt Bridges ◽  
Molecular Systems ◽  
Quadrupole Coupling

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

2019 ◽  
Vol 131 (49) ◽  
pp. 18027-18035 ◽  
Author(s):  
Alexander E. Khudozhitkov ◽  
Jan Neumann ◽  
Thomas Niemann ◽  
Dzmitry Zaitsau ◽  
Peter Stange ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Liquids ◽  
Coupling Constants ◽  
Salt Bridges ◽  
Molecular Systems ◽  
Quadrupole Coupling

Simultaneous determination of deuteron quadrupole coupling constants and rotational correlation times: the model case of hydrogen bonded ionic liquids

2019 ◽  
Vol 21 (46) ◽  
pp. 25597-25605
Author(s):  
A. E. Khudozhitkov ◽  
V. Overbeck ◽  
P. Stange ◽  
A. Strate ◽  
D. Zaitsau ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Liquids ◽  
Relaxation Time ◽  
Coupling Constants ◽  
Model Case ◽  
Correlation Times ◽  
Anisotropic Motion ◽  
Quadrupole Coupling ◽  
Rotational Correlation Times

We show that deuteron quadrupole coupling constants, and reorientational correlation times of molecular bonds N–D that are involved in hydrogen bonding, can be determined from NMR T1 relaxation time experiments simultaneously by assuming anisotropic motion.

scholarly journals NMR Properties of the Cyanide Anion, a Quasisymmetric Two-Faced Hydrogen Bonding Acceptor

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1298
Author(s):  
Ilya G. Shenderovich ◽  
Gleb S. Denisov
Keyword(s):  
Hydrogen Bonding ◽  
Experimental Studies ◽  
Polarizable Continuum Model ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Cyanide Anion ◽  
Molecular Systems ◽  
Polarizable Continuum ◽  
Chemical Shieldings ◽  
Nmr Properties

The isotopically enriched cyanide anion, (13C≡15N)−, has a great potential as the NMR probe of non-covalent interactions. However, hydrogen cyanide is highly toxic and can decompose explosively. It is therefore desirable to be able to theoretically estimate any valuable results of certain experiments in advance in order to carry out experimental studies only for the most suitable molecular systems. We report the effect of hydrogen bonding on NMR properties of 15N≡13CH···X and 13C≡15NH···X hydrogen bonding complexes in solution, where X = 19F, 15N, and O=31P, calculated at the ωB97XD/def2tzvp and the polarizable continuum model (PCM) approximations. In many cases, the isotropic 13C and 15N chemical shieldings of the cyanide anion are not the most informative NMR properties of such complexes. Instead, the anisotropy of these chemical shieldings and the values of scalar coupling constants, including those across hydrogen bonds, can be used to characterize the geometry of such complexes in solids and solutions. 1J(15N13C) strongly correlates with the length of the N≡C bond.

Characterization of Doubly Ionic Hydrogen Bonds in Protic Ionic Liquids by NMR Deuteron Quadrupole Coupling Constants: Differences to H-bonds in Amides, Peptides, and Proteins

2017 ◽  
Vol 56 (45) ◽  
pp. 14310-14314 ◽  
Author(s):  
Alexander E. Khudozhitkov ◽  
Peter Stange ◽  
Benjamin Golub ◽  
Dietmar Paschek ◽  
Alexander G. Stepanov ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Hydrogen Bonds ◽  
Coupling Constants ◽  
Protic Ionic Liquids ◽  
Quadrupole Coupling ◽  
Ionic Hydrogen Bonds

scholarly journals Clusters of Hydroxyl-Functionalized Cations Stabilized by Cooperative Hydrogen Bonds: The Role of Polarizability and Alkyl Chain Length

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4972
Author(s):  
Jule Philipp ◽  
Ralf Ludwig
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Liquids ◽  
Hydrogen Bonds ◽  
Functional Groups ◽  
Chain Length ◽  
Alkyl Chain ◽  
Kinetic Stability ◽  
Alkyl Chain Length ◽  
Coupling Constants ◽  
Imidazolium Cations

We explore quantum chemical calculations for studying clusters of hydroxyl-functionalized cations kinetically stabilized by hydrogen bonding despite strongly repulsive electrostatic forces. In a comprehensive study, we calculate clusters of ammonium, piperidinium, pyrrolidinium, imidazolium, pyridinium, and imidazolium cations, which are prominent constituents of ionic liquids. All cations are decorated with hydroxy-alkyl chains allowing H-bond formation between ions of like charge. The cluster topologies comprise linear and cyclic clusters up to the size of hexamers. The ring structures exhibit cooperative hydrogen bonds opposing the repulsive Coulomb forces and leading to kinetic stability of the clusters. We discuss the importance of hydrogen bonding and dispersion forces for the stability of the differently sized clusters. We find the largest clusters when hydrogen bonding is maximized in cyclic topologies and dispersion interaction is properly taken into account. The kinetic stability of the clusters with short-chained cations is studied for the different types of cations ranging from hard to polarizable or exhibiting additional functional groups such as the acidic C(2)-H position in the imidazolium-based cation. Increasing the alkyl chain length, the cation effect diminishes and the kinetic stability is exclusively governed by the alkyl chain tether increasing the distance between the positively charged rings of the cations. With adding the counterion tetrafluoroborate (BF4−) to the cationic clusters, the binding energies immediately switch from strongly positive to strongly negative. In the neutral clusters, the OH functional groups of the cations can interact either with other cations or with the anions. The hexamer cluster with the cyclic H-bond motive and “released” anions is almost as stable as the hexamer built by H-bonded ion pairs exclusively, which is in accord with recent IR spectra of similar ionic liquids detecting both types of hydrogen bonding. For the cationic and neutral clusters, we discuss geometric and spectroscopic properties as sensitive probes of opposite- and like-charge interaction. Finally, we show that NMR proton chemical shifts and deuteron quadrupole coupling constants can be related to each other, allowing to predict properties which are not easily accessible by experiment.

scholarly journals Cooperativity between the hydrogen bonding and σ-hole interaction in linear NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 complexes (X = Cl, Br; Z = Ar, Kr): a comparative study

2017 ◽  
Vol 95 (5) ◽  
pp. 537-546 ◽  
Author(s):  
Mehdi D. Esrafili ◽  
Hossein Kiani
Keyword(s):  
Hydrogen Bonding ◽  
Coupling Constants ◽  
Interaction Energies ◽  
Cooperative Effects ◽  
Orbital Interactions ◽  
Quadrupole Coupling ◽  
Bonding Properties ◽  
Cooperativity Effects ◽  
Nuclear Quadrupole ◽  
Substantial Change

Quantum chemical calculations are performed to investigate the cooperativity of hydrogen bonding with halogen or aerogen bonding interactions in linear NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 clusters, where X = Cl, Br and Z = Ar, Kr. To understand the cooperativity mechanism in these systems, the corresponding binary NCX···NCH and O3Z···NCH complexes are also considered. The binding distances, interaction energies, and bonding properties of the NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 clusters are analyzed in detail. It is found that the cooperative effects in the hydrogen bonding tend to strengthen X···N and Z···N interactions. For both NCX···(NCH)n and O3Z···(NCH)n clusters, a small bond shrinkage is observed from n = 4 to n = 5, which suggests that the cooperativity effects are almost saturated in the larger clusters (n > 5). As the size of the X or Z atom is increased, the magnitude of the cooperative energy in these systems is also increased, which is mainly ascribed to changes in electrostatic potentials and orbital interactions. Our results indicate that the cooperative effects lead to a substantial change in the 14N nuclear quadrupole coupling constants of the NCH molecule.

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