Local and non-local topological treatment of electronic distributions are applied to a simple out of equilibrium case of an electron-deficient three-atom cluster, B3. The bending movement is described in detail through the onset and disappearance of critical points defining two kinds of molecular structures, characterizing a transition state (TS) and predicting two stable equilibrium geometries. All points in this rich evolution and the structural change in the out of equilibrium conformations has been featured and distinguished by the behavior of the population magnitudes and of the paired and unpaired electron densities within the non-local and local points of view of the topological formalism.
View Article and Find Full Text PDFMuscovite (Ms) and phlogopite (Phl) belong to the 2:1 dioctahedral and trioctahedral layer silicates, respectively, and are the end members of Ms-Phl series minerals. This series was studied in the 2M polytype and modeled by the substitution of three Mg cations in the Phl octahedral sites by two Al and one vacancy, increasing the substitution up to reach the Ms. The series was computationally examined at DFT level as a function of pressure to 9 GPa.
View Article and Find Full Text PDFLow-melting ionic liquid, IL, based on small aliphatic quaternary ammonium cations ([R(1)R(2)R(3)NR](+), where R(1), R(2), R(3) = CH(3) or C(2)H(5), R = C(3)H(7), C(4)H(9), C(6)H(13), C(8)H(17), CF(3)C(3)H(6)) and imide anion were prepared and characterized. The physicochemical and electrochemical properties of these ILs, including melting point, glass transition, and degradation temperatures; viscosity; density; ionic conductivity; diffusion coefficient; and electrochemical stability, were determined. Heteronuclear Overhauser NMR spectroscopy experiments were also performed to point out the presence of pair correlation between the different moieties.
View Article and Find Full Text PDFThe nickel(II) complexes of the mono and di-nucleating Schiff base ligands H(2)L(OMe), H(2)L(NO2) and H(4)L(bis) respectively were synthesized and characterized. H(2)L(OMe) and H(2)L(NO2) differ from one another by the substituents of the phenylene spacer, electron-donating methoxy or electron-withdrawing nitro groups respectively. X-Ray crystal structure analysis shows that the nickel(II) ion(s) resides within a square planar geometry in each complex.
View Article and Find Full Text PDF(19)F labelled tripodal ligands that possess a N(3)O donor set (one phenol, one tertiary amine and either two pyridines or one pyridine and one quinoline) have been synthesized. The fluorine is incorporated either at the phenol O-donor (HL(F) and HL(CF3)) or at the quinoline N-donor (HLq(OMe) and HLq(NO2)). The copper(ii)-phenol complexes (2H)(2+), (1H)(2+), (3H)(2+) and (4H)(2+) as well as the corresponding copper(ii)-phenolate complexes have been characterized.
View Article and Find Full Text PDFThe nickel complexes 1(+)-3(+) exhibit a delocalized radical character, the extent of which depends on the electronic properties of the phenolate para-substituent.
View Article and Find Full Text PDFElectrolytes based on lithium oligoether sulfate, and dissolved in liquid or polymer solvents, are studied. Their properties in term of ionic conductivities, transference numbers, diffusion coefficients, and electrochemical stabilities are reported. The comparison between NMR and electrochemical data, that is, transference numbers and conductivities, provides important information about the existence of ion pairs and aggregates.
View Article and Find Full Text PDFA large number of complexes of the first-row transition metals with non-innocent ligands has been characterized in the last few years. The localization of the oxidation site in such complexes can lead to discrepancies when electrons can be removed either from the metal center (leading to an M((n+1)+) closed-shell ligand) or from the ligand (leading to an M(n+) open-shell ligand). The influence of the ligand field on the oxidation site in square-planar nickel complexes of redox-active ligands is explored herein.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2005