Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy. / Strate, Anne; Neumann, Jan; Niemann, Thomas и др.
в: Physical chemistry chemical physics : PCCP, Том 22, № 13, 07.04.2020, стр. 6861-6867.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy
AU - Strate, Anne
AU - Neumann, Jan
AU - Niemann, Thomas
AU - Stange, Peter
AU - Khudozhitkov, Alexander E.
AU - Stepanov, Alexander G.
AU - Paschek, Dietmar
AU - Kolokolov, Daniil I.
AU - Ludwig, Ralf
PY - 2020/4/7
Y1 - 2020/4/7
N2 - In hydroxy-functionalized ionic liquids, two types of hydrogen bonding coexist: the conventional H-bonds between cation and anion (c-a) and those between cation and cation (c-c), although the interaction between like-charged ions is supposed to be much weaker due to the repulsive Coulomb forces. Counting the cations involved in either (c-a) or (c-c) clusters is a challenge. For that purpose, we recently performed neutron diffraction (ND) measurements and molecular dynamics (MD) simulations at and above room temperature accompanied by NMR solid-state experiments in the glassy state of the ILs. In principle, these methods are suitable for determining the populations of (c-a) and (c-c) cluster species. For different reasons we could only address single temperatures and/or small temperature intervals above 300 K. The by far largest temperature range with reasonable efforts is accessible by simple infrared (IR) spectroscopy. However, counting (c-a) or (c-c) hydrogen bonds is a difficult task due to the different transition dipole moments resulting in varying intensities and broad vibrational bands. Here we present a method for deriving the number of cations involved in (c-a) ion pairs from IR spectra in the OH stretch region. This procedure provides access to the equilibria of (c-a) and (c-c) hydrogen bonds as a function of temperature allowing derivation of the transition enthalpy.
AB - In hydroxy-functionalized ionic liquids, two types of hydrogen bonding coexist: the conventional H-bonds between cation and anion (c-a) and those between cation and cation (c-c), although the interaction between like-charged ions is supposed to be much weaker due to the repulsive Coulomb forces. Counting the cations involved in either (c-a) or (c-c) clusters is a challenge. For that purpose, we recently performed neutron diffraction (ND) measurements and molecular dynamics (MD) simulations at and above room temperature accompanied by NMR solid-state experiments in the glassy state of the ILs. In principle, these methods are suitable for determining the populations of (c-a) and (c-c) cluster species. For different reasons we could only address single temperatures and/or small temperature intervals above 300 K. The by far largest temperature range with reasonable efforts is accessible by simple infrared (IR) spectroscopy. However, counting (c-a) or (c-c) hydrogen bonds is a difficult task due to the different transition dipole moments resulting in varying intensities and broad vibrational bands. Here we present a method for deriving the number of cations involved in (c-a) ion pairs from IR spectra in the OH stretch region. This procedure provides access to the equilibria of (c-a) and (c-c) hydrogen bonds as a function of temperature allowing derivation of the transition enthalpy.
KW - QUADRUPOLE COUPLING-CONSTANTS
KW - INTERACTION STRENGTH
KW - INTERACTION ENERGIES
KW - CHARGE ATTRACTION
KW - DISPERSION FORCES
KW - DYNAMICS
KW - BALANCE
UR - http://www.scopus.com/inward/record.url?scp=85083041725&partnerID=8YFLogxK
U2 - 10.1039/d0cp00303d
DO - 10.1039/d0cp00303d
M3 - Article
C2 - 32202267
AN - SCOPUS:85083041725
VL - 22
SP - 6861
EP - 6867
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 13
ER -
ID: 23982514