Structural characterization and DFT study of VIVO(acac)2 in imidazolium ionic liquids

Abstract

We report the structural characterization of vanadyl acetylacetonate in imidazolium room temperature ionic liquids--bbimNTf(2), bmimNTf(2), C(3)OmimNTf(2), bm(2)imNTf(2), bmimPF(6), bmimOTf, bmimBF(4), bmimMeCO(2), bmimMeSO(4), bmimMe(2)PO(4) and bmimN(CN)(2)--and organic solvents. The complex was characterized by visible electronic (Vis) and EPR spectroscopies. VO(acac)(2) shows solvatochromism in the selected ionic liquids and behaves as in organic solvents, evidencing coordination of the ionic liquid anion in the solvents with higher coordinating ability. The Lewis basicity order obtained for the IL anions was: PF(6)(-) < NTf(2)(-) < OTf(-)≈ MeCO(2)(-) < MeSO(4)(-) < BF(4)(-)≈ N(CN)(2)(-) < Me(2)PO(4)(-). The solvent effect on the spectroscopic data was tentatively examined using linear solvation energy relationships based on the Kamlet-Taft solvent scale (α, β and π*), however no suitable correlation was found with all data. The EPR characterization showed the presence of two isomers in bmimOTf, bmimMeCO(2) and bmimMe(2)PO(4), suggesting coordination of the ionic liquid anions in both equatorial and axial positions. The full geometry optimization of cis-/trans-VO(acac)(2)(OTf)(-) and cis-/trans-VO(acac)(2)(OTf)(mmim) structures was done at the B3P86/6-31G* level of theory. The calculations confirm that the anion OTf(-) is able to coordinate to VO(acac)(2) with the trans isomer being more stable than the cis by 4.8 kcal mol(-1).

Probing Solvation in Ionic Liquids via the Electrochemistry of the DPPH Radical

“…Extending the observations made in molecular solvents, a scale of ionic liquid Lewis basicity is defined and compared to those reported from other electroanalytical and spectroscopic studies. 12,13,21,22 Voltammetry was measured at a platinum (d = 0.61 mm) or gold (d = 1.14 mm) macrodisk working electrode (WE), with a silver wire employed as quasi-reference electrode and a platinum foil as counter electrode. The difference in the formal redox potentials for the oxidation and reduction couples, ΔE°′, was taken directly from CVs recorded at 100 and 200 mV s −1 .…”

“…Bartosik and Mudring studied the UV−vis absorption spectroscopy of the complex [Ni(tmen)(acac)][B(Ph) 4 ] and found that the response was entirely anion dependent. 13 From the wavelength of the absorption maximum, they generated a scale of anion donor strength: 12 Attempts to correlate the trend with the Kamlet−Taft parameters failed. More recently, Schmeisser et al determined DN from the chemical shift of Na + .…”

Study of an Environmentally Friendly Method for the Dissolution of Precious Metal with Ionic Liquid and Iodoalkane

“…Combining the above characterization and analysis results, the possible reaction mechanism is shown in Scheme 2 and Figure 8: Light induces the formation of iodine free radicals in CHI 3 (step (3)), then I captures the electrons on Au 0 to form Au + (step (4)), which then combines with N(CN) 2 − to form AuN(CN) 2 (step ( 5)). Subsequently, the imidazole cation of the ionic liquid forms a stable [Bmim]•[Au(N(CN) 2 ) 2 ] ion pair through various intermolecular forces such as electrostatic attraction, hydrogen bonding, and cation-π bonding with AuN(CN) 2 [34][35][36] (step ( 6)).The ion-pair structure makes the metal shed from the particle surface exist in the ionic liquid in a stable form, and shifts the balance of the oxidation (step (4)) to the right, which further promotes the dissolution reaction and finally promotes the continuous dissolving of the gold particles into the ionic liquid system. In addition, the new ionic liquid BmimI obtained by ion exchange is partially precipitated in the form of crystals.…”

The solvatochromic, spectral, and geometrical properties of nifenazone: a DFT/TD-DFT and experimental study

“…In this regard, solvatochromism is a technique that provides relevant details about the behaviour of drugs in environments of different polarities, and in particular, about solute-solvent interactions. [7][8][9][10][11][12][13][14] This point is crucial for the research and development of novel effective drugs, which is, of course, one of the main aims of the pharmaceutical industry. In addition, understanding the influence of medium properties can provide a powerful tool to control the severity of drug toxicity and the drug efficiency in biological systems.…”