Quantification of Conventional and Nonconventional Charge-Assisted Hydrogen Bonds in the Condensed and Gas Phases.
Charge-assisted hydrogen bonds (CAHBs) play critical roles in many systems from biology through to materials. In none of these areas has the role and function of CAHBs been explored satisfactorily because of the lack of data on the energy of CAHBs in the condensed phases. We have, for the first time, quantified three types of CAHBs in both the condensed and gas phases for 1-(2'-hydroxylethyl)-3-methylimidazolium acetate ([C2OHmim][OAc]). The energy of conventional OH···[OAc](-) CAHBs is ∼10 kcal·mol(-1), whereas nonconventional C(sp2)H···[OAc](-) and C(sp3)H···[OAc](-) CAHBs are weaker by ∼5-7 kcal·mol(-1). In the gas phase, the strength of the nonconventional CAHBs is doubled, whereas the conventional CAHBs are strengthened by <20%. The influence of cooperativity effects on the ability of the [OAc](-) anion to deprotonate the imidazolium cation is evaluated. The ability to quantify CAHBs in the condensed phase on the basis of easier accessible gas-phase estimates is highlighted.
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences , Arbuzov Street 8, 420088 Kazan, Russia.
Sergey A
SA
Katsyuba
Department of Quantum Chemistry, Mendeleev University of Chemical Technology , Miusskaya Square 9, 125047 Moscow, Russia.
Mikhail V
MV
Vener
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences , Arbuzov Street 8, 420088 Kazan, Russia.|Institut de Nanosciences et Cryogénie, SP2M/L_sim, CEA , 17 Rue des Martyrs, 38054 Grenoble, France.
Elena E
EE
Zvereva
Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) EPFL - BCH , CH-1015 Lausanne, Switzerland.
Zhaofu
Z
Fei
Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) EPFL - BCH , CH-1015 Lausanne, Switzerland.
Rosario
R
Scopelliti
Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn , Beringstrasse 4, 53115 Bonn, Germany.
Jan Gerit
JG
Brandenburg
Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) EPFL - BCH , CH-1015 Lausanne, Switzerland.
Sviatlana
S
Siankevich
Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) EPFL - BCH , CH-1015 Lausanne, Switzerland.
Paul J
PJ
Dyson
IR intensities; carbenes; energy; frequency shifts; ionic liquids; solid-state DFT