The structure and potentials of the interaction of complexes of polyatomic anions with Li+, Na+, and the molecules of aprotic solvents

Perelygin, I. S.; Shatokhin, S. A.

doi:10.1016/s0022-2860(97)00220-2

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…4,7,13,21 For example, the percent increase in the integrated linear absorption coefficient in the ν 1 and ν 5 regions (from 2850 to 3100 cm -1 ) between the pure ACN spectrum and the spectra of 0.887 M LiClO 4 and 0.881 M NaClO 4 -ACN solutions is 21.9% and 22.3%, respectively. Furthermore, the calculated bond energy between an ACN molecule and ClO 4is 34 kJ mol -1 , compared to 173 kJ mol -1 of an ACN-Li + bond 41,42 and 24.8 kJ mol -1 of the calculated binding energy of an ACN antiparallel dimer. 43 These observations suggest that the strength of a ClO 4 --ACN interaction might be comparable to that of cation solvation.…”

Section: Resultsmentioning

confidence: 86%

“…Semiempirical quantum mechanical calculations show that the lowest energy configuration of an anion-ACN complex is with the anion oriented along one of the C-H bonds on the methyl group. 41,42 Accordingly, SCNand Ianions give rise to wavenumber shifts (of as much as 20 cm -1 ) and increases in the molar absorption coefficients of the C-H stretching bands of ACN (ν 1 and ν 5 ). 21 While the ClO 4and NO 3anions do not give rise to detectable shifts in the ν 1 and ν 5 bands, these anions do cause increases in the bands' molar absorption coefficients.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, if θ is the aforementioned fraction of ion pairs and n IP and n M + are the solvation numbers of the ion pair and the free cation, respectively, then and follows from eq 6 that the dependence of a cation-solvating ACN band on electrolyte concentration would be observed either if θ were nearly constant over the electrolyte concentration range studied or if IP n IP = M + n M + . Since semiempirical quantum mechanical calculations by Perelygin 41,42 show that the difference between the charge distribution of an ACN molecule solvating a free cation and the charge distribution of an ACN molecule solvating a cation in a solvent-separated ion pair is not significant when compared with the difference between the charge distribution of an ACN molecule solvating a free cation and the charge distribution of a free ACN molecule, it may be possible that IP n IP = M + n M + as long as the formation of an ion pair does not significantly displace ACN from the cation's solvation shell. This result of Perelygin's computations also supports the assumption that both free and ion-paired cationsolvating ACN bands have the same wavenumber positions.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, Perelygin has reported that the vibrational spectrum of ACN is significantly affected by the anion present. Semiempirical quantum mechanical calculations show that the lowest energy configuration of an anion−ACN complex is with the anion oriented along one of the C−H bonds on the methyl group. , Accordingly, SCN - and I - anions give rise to wavenumber shifts (of as much as 20 cm -1 ) and increases in the molar absorption coefficients of the C−H stretching bands of ACN (ν 1 and ν 5 ) . While the ClO 4 - and NO 3 - anions do not give rise to detectable shifts in the ν 1 and ν 5 bands, these anions do cause increases in the bands' molar absorption coefficients. ,,, For example, the percent increase in the integrated linear absorption coefficient in the ν 1 and ν 5 regions (from 2850 to 3100 cm -1 ) between the pure ACN spectrum and the spectra of 0.887 M LiClO 4 and 0.881 M NaClO 4 −ACN solutions is 21.9% and 22.3%, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Ion−Solvent Interactions in Acetonitrile Solutions of Lithium, Sodium, and Tetraethylammonium Perchlorate Using Attenuated Total Reflectance FTIR Spectroscopy

Loring

Fawcett

1999

J. Phys. Chem. A

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A vibrational spectroscopic study of ion solvation in LiClO 4 -, NaClO 4 -, and tetraethylammonium perchlorateacetonitrile solutions has been performed using attenuated total reflection FTIR spectroscopy. Spectra were curve fitted in the CtN stretching and C-CtN bending regions of the solvent using a multiple-dimensional fitting routine that factors an entire set of solution spectra into their physically real basis spectra according to a user supplied mathematical model. The spectra of the solutions of tetraethylammonium perchlorate in acetonitrile were shown to be a linear combination of one physically real basis spectrum that accounts for self-associated acetonitrile and another that accounts for the spectrum of the acetonitrile molecules associated with the perchlorate anion. It is demonstrated for the first time that the CtN stretching band of acetonitrile molecules associated with ClO 4anions has a significantly different molar absorption coefficient from the same band for self-associated acetonitrile. The spectra of LiClO4 and NaClO4 solutions in acetonitrile were shown to be a linear combination of one physically real basis spectrum that accounts for the spectrum of self-associated acetonitrile and another that accounts for the spectrum of the acetonitrile molecules associated with both the cation and the anion. The fractional contribution of these physically real basis spectra to the solution spectra depends on the total electrolyte concentration, rather than on the extent of ion pairing. Two possible rationalizations for this phenomenon are discussed.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Ion−Solvent Interactions in Acetonitrile Solutions of Lithium, Sodium, and Tetraethylammonium Perchlorate Using Attenuated Total Reflectance FTIR Spectroscopy

Loring

Fawcett

1999

J. Phys. Chem. A

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Ion aggregation and phase separation in amorphous poly(nitrile)-based lithium conducting polymer electrolytes

Бушкова¹,

Erkabaev²,

Yaroslavtseva³

et al. 2019

Solid State Ionics

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Sitting-Atop Metallo-Porphyrin Complexes: Experimental and Theoretical Investigations on Such Elusive Species

et al. 2009

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The interaction between the sodium cation and two meso-aryl porphyrins (tetraphenylporphyrin, TPP, and tetra(4-methoxyphenyl)porphyrin, TMPP) leads to the formation of new species that have been identified as Sitting-Atop (SAT) complexes, where the metal ion interacts with the N atoms of the porphyrin core without the concomitant deprotonation of the N-H groups. These species have been attained in low polarity solvent through the interaction of the porphyrin free bases with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), and investigated in situ through a combination of spectroscopic techniques, such as UV/vis absorption and fluorescence (static and time-resolved), resonance light scattering, FT-IR, and (1)H NMR. All spectroscopic evidence points to the occurrence of a single equilibrium between each parent compound and its SAT complex, ruling out the presence of other metallo-, protonated, or aggregated porphyrins in solution. The 1:1 stoichiometry of the adducts has been determined via continuous variation method (Job's plot), and an estimate of the corresponding association constants in CH(2)Cl(2) at 298 K have been obtained by UV/vis titration (K(eq) = (9 +/- 4) x 10(5) L mol(-1) and (5 +/- 2) x 10(6) L mol(-1) for TPP and TMPP, respectively). Density-functional theory (DFT) calculations on SAT model complexes, [NaTPP(PF(6))] and [NaTMPP(PF(6))], have provided information on the molecular structure of these elusive species and on the nature and strength of the sodium-porphyrin interaction. It is found that the sodium ion is bound to the four nitrogen atoms of the porphyrin core. The involvement of the pyrrolic N atoms results in a modest but not negligible elongation of the N-H bonds, pyramidalization of the hydrogen atoms, and blue shift of the N-H stretching frequencies. Electronic structure and energy decomposition analysis reveal that covalent interactions, mainly consisting of porphyrin to sodium charge transfer interactions, are an important component of the sodium-porphyrin bond. Time-dependent DFT (TDDFT) calculations of the lowest excited states of the model systems provide an unambiguous interpretation of the absorption and emission properties of the experimentally identified SAT complexes.

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The structure and potentials of the interaction of complexes of polyatomic anions with Li+, Na+, and the molecules of aprotic solvents

Cited by 5 publications

References 7 publications

Ion−Solvent Interactions in Acetonitrile Solutions of Lithium, Sodium, and Tetraethylammonium Perchlorate Using Attenuated Total Reflectance FTIR Spectroscopy

Ion−Solvent Interactions in Acetonitrile Solutions of Lithium, Sodium, and Tetraethylammonium Perchlorate Using Attenuated Total Reflectance FTIR Spectroscopy

Ion aggregation and phase separation in amorphous poly(nitrile)-based lithium conducting polymer electrolytes

Sitting-Atop Metallo-Porphyrin Complexes: Experimental and Theoretical Investigations on Such Elusive Species

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