Metal-containing ionic liquids (ILs) have been recognized as potential solvents, catalysts, catalyst precursors and reagents for many organic processes. In this work, several quantum-chemical parameters, including the surface electrostatic potential (Vs,max and Vs,min), the lowest surface average local ionization energy (I̅s,min), and the electrostatic potential at the position of an atom (EPnuc...

We developed surface grid-based solvation free energy density (Surface-SFED) models for 36 commonly used polar solvents. The parametrization was performed with a large and diverse set of experimental solvation free energies mainly consisting of combinations of polar solvent and multipolar solute. Therefore, the contribution of hydrogen bonds was dominant in the model. In order to increase the a...

The origin of catalysis and selectivity induced by room temperature ionic liquids in several organic reactions has putatively been associated with the concept of cation effect (hydrogen bond donor ability of the ionic liquids) or anion effect (hydrogen bond accepting ability of the ionic liquids). We show that there may be cases where this a priori classification may not be correctly assigned. ...

We described a dual turn-on probe sensitive to both acidity and basicity, which could be designed by connecting a fluorophore to a quencher via metal-ligand interaction. Atto488-labeled nitrilotriacetic acid and polyhistidine peptide were used as the fluorophore and the quencher, respectively, and linked to each other by coordination with a cobalt(II) ion. After preparation of the probe, the pH...

A possibility of non-conventional two-step protonation of 1,8-bis(dimethylamino)naphthalene (proton sponge) is discussed. Unlike the generally accepted mechanism, involving relatively slow direct penetration of a proton into the cleft between the peri-NMe2 groups, it consists of the rapid addition of a proton to the out-inverted NMe2 group with the subsequent slower rotational transfer of the p...

Basicity constants for a series of 3,7-diazabicyclo[3.3.1]nonane derivatives in acetonitrile with a variation over 13 orders of magnitude have been determined using a spectrophotometric titration technique. An excellent correlation between basicity and calculated proton affinities obtained at PCM-B3LYP/6-31+G(d)//B3LYP/6-31G(d) level was found. The results are discussed in terms of substituent ...

A calcium phosphate cement (CPC) was shown to have the necessary attributes for endodontic materials except adequate basicity needed for antimicrobial properties. To enhance its basicity, tricalcium silicate (Ca3SiO5), a highly alkaline compound, was added to CPC at a mass fraction of 0.25, 0.5 or 0.75. The basicity, acid neutralization and physical properties of the CPC-Ca3SiO5 composites were...

The effects of preparative parameters on the surface basicity, composition, and transesterification activities of several Ca-La metal oxide catalysts were investigated. Four different preparation methods: ammonia-ethanol-carbon dioxide precipitation, physical mixing, impregnation, and coprecipitation, were studied. It was found that the ammoniaethanol-carbon dioxide precipitation method resulte...

Rate constants for the reactions of substituted quinuclidines with pnitrophenyl phosphate, 2,4-dinitrophenyl phosphate, 2,4-dinitrophenyl phosphate complexed with calcium, and phosphorylated pyridine decrease with increasing pKa of the amine. Plots of log k against pK, give slopes of @ , , = -0.05, -0.10, -0.1 1, and 4.10, respectively, for these.compounds; &, = -0.01 for phosphorylated 4-morph...

The thermodynamic selectivity for Gd(3+) relative to Ca(2+), Zn(2+), and Fe(3+) of two ligands of potential interest as magnetic resonance imaging (MRI) contrast agents has been determined by NMR spectroscopy and potentiometric and spectrophotometric titration. The two hexadentate ligands TREN-6-Me-3,2-HOPO (H(3)L2) and TREN-bisHOPO-TAM-EA (H(4)L3) incorporate 2,3-dihydroxypyridonate and 2,3-di...