Freezing the Motion in Hydroxy-Functionalized Ionic Liquids–Temperature Dependent NMR Deuteron Quadrupole Coupling Constants for Two Types of Hydrogen Bonds Far below the Glass Transition

2020 ◽  
Vol 11 (15) ◽  
pp. 6000-6006 ◽  
Author(s):  
Alexander E. Khudozhitkov ◽  
Thomas Niemann ◽  
Peter Stange ◽  
Masaki Donoshita ◽  
Alexander G. Stepanov ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Glass Transition ◽  
Hydrogen Bonds ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Quadrupole Coupling

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

Temperature dependent deuterium quadrupole coupling constants of short hydrogen bonds

2006 ◽  
Vol 790 (1-3) ◽  
pp. 152-159 ◽  
Author(s):  
Xingang Zhao ◽  
Paolo Rossi ◽  
Valeri Barsegov ◽  
Jun Zhou ◽  
Jeffrey N. Woodford ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Quadrupole Coupling ◽  
Short Hydrogen Bonds

19F Nuclear Quadrupole Coupling in some Halomethanes

1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Temperature Dependence ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Distribution Method ◽  
Quadrupole Coupling ◽  
Time Differential ◽  
Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

High Pressure NQR Study of the Phase Transition in Anilinium Iodide

1986 ◽  
Vol 41 (1-2) ◽  
pp. 290-293
Author(s):  
Mariusz Maćkowiak ◽  
Maria Zdanowska-Fra̧zek ◽  
Piotr Kozioł ◽  
Jan Stankowski ◽  
Alarich Weiss
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Transition Temperature ◽  
Hydrogen Bonds ◽  
Transition Point ◽  
Pressure Coefficient ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The 127I NQR frequency in anilinium iodide C6H5NH3⊕I⊖ was studied at pressures up to 300 MPa and within the temperature range 77 K - 290 K. With increasing pressure the order-disorder transition point Tc is shifted to higher temperatures. The pressure coefficient of the phase transition temperature amounts to dTc/dp = 4.2 x 10-2 deg MPa-1. The pressure coefficient of the NQR frequency is negative. In addition, the 12'I nuclear quadrupole coupling constants and the respective asymmetry parameters η were evaluated as a function of pressure. The results confirm the close connection between the mechanism of the phase transition and the dynamics of the N - H⊕ ...I⊖ hydrogen bonds.

Preliminary Results of a 20 K X-Ray Study of Citrinin

1993 ◽  
Vol 48 (1-2) ◽  
pp. 99-104 ◽  
Author(s):  
R. Destro ◽  
F. Merati
Keyword(s):  
Dipole Moment ◽  
Hydrogen Bonds ◽  
Charge Density ◽  
Topological Analysis ◽  
Coupling Constants ◽  
Molecular Dipole ◽  
X Ray ◽  
A Value ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

Abstract A total of about 37 000 diffracted intensities has been measured at 20 K for a spherical single crystal of citrinin. Using a multipole formalism to interpret the X-ray data, maps of the charge density and of its Laplacian, as well as for the electrostatic potential have been derived. A value of 7(2) D has been obtained for the magnitude of the molecular dipole moment. A study of the electric field gradient (EFG) at the nuclei has yielded the atomic quadrupole coupling constants (QCC) and asymmetry parameters (η). A topological analysis of the charge density has been performed to characterize the intramolecular covalent and 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.

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