13755-29-8Relevant articles and documents
Solvation of Anions in Water-Acetonitrile Mixtures
Miyaji, Kiyoshi,Morinaga, Kenichi
, p. 1695 - 1700 (1986)
The enthalpies of transfer from water to mixtures with acetonitrile (ΔH0t) for various anions reach maxima at a mole fraction of acetonitrile (χAN) ca. 0.3, and decrease linearly and in parallel in the intermediate region.A linear relation is found between ΔH0t at χAN 0.3 and the hydration enthalpies for halide and symmetrical ions.This finding and the parallel χAN dependence of ΔH0t in the intermediate region are interpreted on the basis of the linear relation between the solvation enthalpies and the entropies for the halide ions.The reduction in the hydrogen-bonding interaction extending beyond the primary hydration sphere (ΔHINT) for halide ions in the mixtures is estimated based on a modified Eley and Evans hydration model.At χAN 0 to ca. 0.3, ΔHINT compared with that in water agree well with the observed ΔH0t, indicating that the increase in ΔH0t is due to the reduction in the outer hydration sphere interaction.However, they split gradually at χAN above 0.3.The adequacy of the modifications in the treatment of the solvation enthalpy cycle in the mixtures is re-evaluated from the structural viewpoint.The exothermic change in the intermediate region may be attributable to the reduction in the cavity formation energy.
Carba-closo-dodecaborates – Synthesis, Structure, and Energetics
Hepp, Alexander,Labbow, René,Rei?, Fabian,Schulz, Axel,Villinger, Alexander
, p. 2905 - 2914 (2018)
A full set of analytical data of salts (e.g., Me3NH+, Cs+, Ag+) bearing nido-[B11H14]–, closo-[CHB11H11]–, and chlorinated congener [CHB11Cl11]– is reported. Structures and energetics of [CHB11H11–nXn]– and [B12XmH12–m]2– (n = 5, 11; m = 0, 12; X = halogen, CH3, CF3) and their protonated and silylated forms are studied. A direct correlation between theoretical calculated NICS values, gas-phase acidities, and experimentally determined 13C NMR shifts is discussed.
Syntheses of tricyanofluoroborates M[BF(CN)3] (M = Na, K): (CH3)3SiCl catalysis, countercation effect, and reaction intermediates
Sprenger, Jan A. P.,Landmann, Johannes,Drisch, Michael,Ignatev, Nikolai,Finze, Maik
, p. 3403 - 3412 (2015)
Potassium tricyanofluoroborate, K[BF(CN)3], which is the starting material for tricyanofluoroborate room-temperature ionic liquids [N. Ignatev et al. J. Fluorine Chem., submitted] was obtained on a molar scale (140 g) from Na[BF4] and (CH3)3SiCN with a purity of up to 99.9%. The initial product of the reaction that was catalyzed by (CH3)3SiCl was Na[BF(CN)3]·(CH3)3SiCN that was characterized by multinuclear NMR and vibrational spectroscopy, elemental analysis, differential scanning calorimetry, and single-crystal X-ray diffraction. Na[BF(CN)3]·(CH3)3SiCN was converted to K[BF(CN)3] via a simple extraction protocol. The catalytic effect of (CH3)3SiCl was evaluated and some intermediates of the reaction, including the isocyanoborate anion [BF(NC)(CN)2]-, were identified using multinuclear NMR and vibrational spectroscopy. K[BF2(CN)2] also reacted with (CH3)3SiCN in the presence of (CH3)3SiCl, to result in K[BF(CN)3]. The interpretation of the experimental observations was supported by data derived from density functional theory (DFT) calculations. In addition, the influence of selected countercations of the tetrafluoroborate anion on the progress of the (CH3)3SiCl-catalyzed reaction was studied. The fastest reaction was observed for Na[BF4], while the conversion of [BF4]- to [BF(CN)3]- was slower with the countercation K+. Li[BF4] and [Et4N][BF4] were converted under the reaction conditions applied to Li[BF2(CN)2] and [Et4N][BF2(CN)2] only.
Fe4 cluster and a buckled macrocycle complex from the reduction of [(dmgBF2)2Fe(L)2] (L = MeCN, tBuiNC)
Rose, Michael J.,Winkler, Jay R.,Gray, Harry B.
, p. 1980 - 1982 (2012)
We report the syntheses, X-ray structures, and reductive electrochemistry of the FeII complexes [(dmgBF2)2Fe(MeCN) 2] (1; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF 2)Fe(tBuiNC)2] (2; tBuiNC = tert-butylisocyanide). The reaction of 1 with Na/ Hg amalgam led to isolation and the X-ray structure of [(dmgBF2)2Fe(glyIm)] (3; glyIm = glyimine), wherein the (dmgBF2)2 macrocyclic frame is bent to accommodate the binding of a bidentate apical ligand. We also report the Xray structure of a rare mixed-valence Fe4 cluster with supporting dmg-type ligands. In the structure of [(dmg2BF2)3Fe3(1/2dmg) 3Fe(O)6] (4), the (dmgBF2)2 macrocycle has been cleaved, eliminating BF2 groups. Density functional theory calculations and electron paramagnetic resonance data are in accordance with a central FeIII ion surrounded by three formally Fe IIdmg2BF2 units.
Tris(5-methylpyrazolyl)methane: Synthesis and properties of its iron(II) complex
Goodman, Margaret A.,Nazarenko, Alexander Y.,Casavant, Barbara J.,Li, Zhanjie,Brennessel, William W.,Demarco, Michael J.,Long, Gen,Goodman, M. Scott
, p. 1084 - 1093 (2012)
The new ligand, tris(5-methylpyrazolyl)methane (1), has been prepared by the reaction of n-butyl lithium with tris(pyrazolyl)methane followed by trimethylation of the tetralithiated species with methyl iodide. The BF 4-, ClO4-, and BPh 3CN- salts of the Fe(II) complex of this ligand were also synthesized. The X-ray crystal structure of the BF4- complex (2) at 100 K had Fe-N bond lengths of 1.976 A, indicative of a low spin Fe(II) complex, while at room temperature, the structure of this complex had a Fe-N bond distance close to 2.07 A, indicative of an admixture of approximately 50% low-spin and 50% high-spin. The solid-state structure of the complex with a ClO4- counterion was determined at 5 different temperatures between 173 and 293 K, which allowed the thermodynamic parameters for the spin-crossover to be estimated. Moessbauer spectra of the BF4- complex further support spin-state crossover in the solid state with a transition temperature near 300 K. UV-visible spectroscopy and 1H NMR studies of 2 show that the transition temperature in solution is closer to 400 K. No spin-crossover was observed for [Fe(1) 2]2+·2BPh3CN-. The results allow the separation of effects of groups in the 3-position from those in the 5-position on tpm ligands, and also point toward a small cooperative effect in the spin-crossover for the Fe(II) complex.
Metathetical reactions in the system Na(K)PF6 - LiBF4 - Aprotic media
Plakhotnyk, Andriy V.,Tarasova, Lidiya D.,Ernst, Ludger,Schmutzler, Reinhard
, p. 1840 - 1842 (2005)
19F NMR spectroscopy, X-ray powder diffraction, elemental analysis, and ab initio quantum chemical calculations were used to study metathetical reactions between potassium or sodium hexafluorophosphate and lithium tetrafluoroborate in a mixture of propylene carbonate (PC) - dimethyl carbonate (DMC). It was shown that the increase in size of the cations in the second coordination sphere from Na+ to K+ results in an increase of the equilibrium conversion. This is in agreement with the influence of the cation size on the solubility of tetrafluoroborates in the media investigated.
Calorimetric study of alkali metal tetrafluoroborates
Gavrichev,Sharpataya,Gorbunov
, p. 225 - 238 (1996)
Adiabatic calorimetric investigation of the low-temperature heat capacity of sodium tetrafluoroborate as well as a DSC study of the thermal behavior of potassium tetrafluoroborate and of lithium tetrafluoroborate and its hydrates were carried out. Temperatures and enthalpies of phase transitions at temperature above ambient were determined for potassium tetrafluoroborate, lithium tetrafluoroborate, and lithium tetrafluoroborate mono- and trihydrate. It was demonstrated that lithium tetrafluoroborate has only one phase transition in the solid at 300 K.
Improved procedures for the generation of diborane from sodium borohydride and boron trifluoride
Kanth, Josyula V. B.,Brown, Herbert C.
, p. 1795 - 1802 (2000)
Improved procedures for the generation of diborane by the reaction of NaBH4 in triglyme or tetraglyme with the BF3 adducts of di-n-butyl ether, tert-butyl methyl ether, monoglyme, dioxane, and tetrahydropyran were developed. In these
Synthesis and properties of diacetatodinitrosylmolybdenum complex as precursor for olefin metathesis catalyst
Keller
, p. L9-L11 (1989)
Reaction of the [Mo(NO)2]2+ moiety with a suitable ligands is a very convenient method to synthesize different dinitrosylmolybdenum complexes. It was also applied for the synthesis of a new compound of empirical formula Mo(NO)2(O2CMe)2. The reaction of catalyst precursor with EtAlCl2 was spectroscopically examined (IR in the v(NO) region). Reagent concentrations were as in the metathesis reaction. The reaction between Mo(NO)2(O2CMe)2 and EtAlCl2 is accompanied by liberation of ethane. During the stable period of the system (decrease in intensity of the bands v(NO) 1%) one molar equivalent (vs. precursor concentration) of ethane evolved.
Thermal studies of potassium tetrahydroborate?sodium tetrafluoroborate mixtures
Saldin,Sukhovei,Savchenko,Slobodyuk,Kavun, V. Ya.
, p. 489 - 497 (2017/05/05)
The KBH4?NaBF4 mixture was studied by thermal analysis (differential scanning calorimetry). Chemical analysis, X-ray powder diffraction analysis, IR spectroscopy, and 11B and 19F MAS NMR spectroscopy showed that the primary stage of the complex pyrolysis process is a metathesis reaction between components to form a new mixture, NaBH4?KBF4, the decomposition of which with the release of gaseous products and the formation of polyhedral borohydride compounds (mainly B12H12 2-) in the solid residue begins at a temperature of about 563 K. At a certain ratio between reactants in the initial mixture KBH4?NaBF4, the B12H12 2- anion can form with the material participation of the BF4 - anion.
