Reaction of 1-ethyl-3-methylimidazolium chloride (EMICl) and anhydrous hydrogen fluoride gives a nonvolatile, room temperature molten salt. EMIF.2.3HF. The elemental analysis, vibrational, and nuclear magnetic resonance spectroscopy suggests the presence of oligomeric anions. (HF) n F - , in the salt The liquid is stable in air and able to he handled in a Pyrex glass vessel. The specific conductivity is 100 mS cm -1 at 298 K. which is extremely high compared with other salts of this kind. The high conductivity is realized by its low viscosity(4.85cP at 298 K) The liquid temperature ranges from 180 to 350 K, and electro-chemical window is about 3.2 V when a vitreous carbon is used for the electrode material.

A Highly Conductive Room Temperature Molten Fluoride: EMIF ⋅ 2.3 HF

Acidic 1-ethyl-3-methylimidazolium fluoride: a new room temperature ionic liquid

Reaction of some N-alkylimidazolium chlorides with anhydrous hydrogen fluoride (HF) gave nonvolatile room temperature molten salts (room temperature ionic liquids), RMImF.2.3HF where RMIm = 1,3-dimethylimidazolium (DMIm), 1-ethyl-3-methylimidazolium (EMIm), 1-methyl-3-propylimidazolium, 1-butyl-3-methylimidazolium, 1-methyl-3-pentylimidazolium, and 1-hexyl-3-methylimidazolium. Vacuum stable salts at room temperature exhibited similar stoichiometry regardless of the type of cation. In the differential scanning calorimetry (DSC) curve, DMImF.2.3HF exhibited both the freezing and melting on the cooling and heating process, respectively, while EMImF.2.3HF showed the glass transition on the cooling process and devitrification and melting on the heating process. The other salts show only the glass transition on the DSC curves. High specific conductivities, 110 and 100 mS cm -1 , were observed at 298 K for DMImF.2.3HF and EMImF.2.3HF, respectively. Introduction of the longer alkyl side chains to the imidazolium cation increased the viscosity and decreased the conductivity. These salts were stable in air and did not etch a Pyrex glass container at ambient conditions. The dissociation pressures of HF from the salts were negligibly small at ambient condition. The electrochemical windows of these salts was about 3 V.

Physicochemical Properties of 1,3-Dialkylimidazolium Fluorohydrogenate Room-Temperature Molten Salts

The hydrogen bond in the water dimer is studied within the SCF-MO-LCAO framework, using a large Gaussian basis set to approximate the wavefunction. A geometry search restricted to structures with linear and bifurcated hydrogen bonds is performed and the associated potential energy curves are displayed. The minimum energy geometry of the water dimer is found to form a linear hydrogen bond with a hydrogen bond distance of 2.04 A and a binding energy of 4.84 kcal/mole relative to the monomer (exp. 5.0 kcal/mole). No semistable structures are found. The charge density and charge density difference maps are discussed for the structure with a linear hydrogen bond for different subsystem (water) separations, including the minimum energy geometry. The dipole moment of the dimer is computed to be 1.69 a.u. The shift of the IR bands on hydrogen bond formation is explained qualitatively by comparing the potential energy curves of the hydrogen in the OH-bonds of the monomer and the dimer, and the intensity increase of the fundamental OH-stretching band is computed. The shift of the proton magnetic resonance signal is discussed qualitatively by inspecting the charge density change on hydrogen bond formation, and the average diamagnetic shielding is calculated.

SCF-MO-LCGO studies on hydrogen bonding. The water dimer

Three Cu2+-containing coordination polymers were synthesized and characterized by experimental (X-ray diffraction, magnetic susceptibility, pulsed-field magnetization, heat capacity, and muon-spin relaxation) and electronic structure studies (quantum Monte Carlo simulations and density functional theory calculations). [Cu(HF2)(pyz)2]SbF6 (pyz = pyrazine) (1a), [Cu2F(HF)(HF2)(pyz)4](SbF6)2 (1b), and [CuAg(H3F4)(pyz)5](SbF6)2 (2) crystallize in either tetragonal or orthorhombic space groups; their structures consist of 2D square layers of [M(pyz)2]n+ that are linked in the third dimension by either HF2− (1a and 1b) or H3F4− (2). The resulting 3D frameworks contain charge-balancing SbF6− anions in every void. Compound 1b is a defective polymorph of 1a, with the difference being that 50% of the HF2− links are broken in the former, which leads to a cooperative Jahn−Teller distortion and dx2−y2 orbital ordering. Magnetic data for 1a and 1b reveal broad maxima in χ at 12.5 and 2.6 K and long-range magnetic order...

Strong H...F hydrogen bonds as synthons in polymeric quantum magnets: structural, magnetic, and theoretical characterization of [Cu(HF2)(pyrazine)2]SbF6, [Cu2F(HF)(HF2)(pyrazine)4](SbF6)2, and [CuAg(H3F4)(pyrazine)5](SbF6)2.

The infrared absorption of KH2F3 and KD2F3in the solid state was measured between 4 000 and 200 cm−1 The observed bands can be assigned to the stretching and bending modes of the bent H2F3− ion. A normal coordinate analysis was carried out to determine the Urey–Bradley force constants. The results suggest that the hydrogen atoms are not exactly halfway between two fluorine atoms, contrary to the case of the HF2− ion.Les spectres infrarouges de KH2F3 et KD2F3 a l'etat solide ont ete mesures entre 4 000 et 200 cm−1 afin d'identifier les vibrations fondamentales de l'anion H2F3−. Les constantes de forces de rappel selon le modele de Urey–Bradley ont pu etre determinees par analyse des coordonnees normales. Les resultats indiquent que les atomes d'hydrogene ne sont pas exactement a mi-chemin entre deux atomes de fluor, contrairement au cas de l'ion HF2−.

Infrared spectra of KH2F3 and the structure of the H2F3− ion

Short results are given of the application of the CNDO/II method to hydrogen bonding. Formic acid (monomer and dimer), trifluoroacetic acid and the hydrogen bis(trifluoroacetate)ion were treated.

A. Ocvirk

Papers

Infrared spectra of KH2F3 and the structure of the H2F3− ion

Application of CNDO/II to some hydrogen-bonded systems