Solvation of LiClO4 and NaClO4 in deuterated acetonitrile studied by means of infrared and Raman spectroscopy

Ionic conduction mechanism in high concentration lithium ion electrolytes

The conduction mechanism of a family of high concentration lithium electrolytes (HCEs) is investigated. It is found in all HCEs that the molecular motions are regulated by the anion size and correlated to the HCE ionic resistivity. From the results, a mechanism involving highly correlated ionic networks is derived.

Solvation Structure of Li+ in Concentrated Acetonitrile and N,N-Dimethylformamide Solutions Studied by Neutron Diffraction with 6Li/7Li Isotopic Substitution Methods

Neutron diffraction measurements on ⁶Li/⁷Li isotopically substituted 10 and 33 mol % *LiTFSA (lithium bis(trifluoromethylsulfonyl)amide)-AN-d₃ (acetonitrile-d₃) and 10 and 33 mol % *LiTFSA-DMF-d₇(N,N-dimethylformamide-d₇) solutions have been carried out in order to obtain structural insights on the first solvation shell of Li⁺ in highly concentrated organic solutions. Structural parameters concerning the local structure around Li⁺ have been determined from the least squares fitting analysis of the first-order difference function derived from the difference between carefully normalized scattering cross sections observed for ⁶Li-enriched and natural abundance solutions. In 10 mol % LiTFSA-AN-d₃ solution, 3.25 ± 0.04 AN molecules are coordinated to Li⁺ with a intermolecular Li⁺···N(AN) distance of 2.051 ± 0.007 Å. It has been revealed that 1.67 ± 0.07 AN molecules and 2.00 ± 0.01 TFSA^- are involved in the first solvation shell of Li⁺ in the 33 mol % LiTFSA-AN solution. The nearest neighbor Li⁺···N_AN and Li⁺···O_TFSA^- distances are obtained to be r(Li⁺···N) = 2.09 ± 0.01 Å and r(Li⁺···O) = 1.88 ± 0.01 Å, respectively. The first solvation shell of Li⁺ in the 10 mol % LiTFSA-DMF-d₇ solutions contains 3.4 ± 0.1 DMF molecules with an intermolecular Li⁺···O_DMF distance of 1.95 ± 0.02 Å. In highly concentrated 33 mol % LiTFSA-DMF-d₇ solutions, there are 1.3 ± 0.2 DMF molecules and 3.2 ± 0.2 TFSA^- in the first solvation shell of Li⁺ with intermolecular distances of r(Li⁺···O_DMF) = 1.90 ± 0.02 Å and r(Li⁺···O_TFSA^-) = 2.01 ± 0.01 Å, respectively. The Li⁺···TFSA^- contact ion pair stably exists in highly concentrated 33 mol % LiTFSA-AN and -DMF solutions.

Solvation of anions in acetonitrile solutions: FTIR and quantum chemical study for Br-, ClO4-, AsF6-, and CF3SO3. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020;229:117873. [PMID: 31813727 DOI: 10.1016/j.saa.2019.117873]

Anion solvation in acetonitrile solutions was comparatively studied using FTIR spectroscopy and quantum chemical calculations at the RTF + MP2/6-311G** level of theory with solvation model density (SMD) corrections. Infrared spectra for all stable anionic complexes X^-(CH₃CN)_n (where X^- = Br^- (monatomic halide), ClO₄^- (polyatomic tetrahedral), AsF₆^- (polyatomic octahedral), CF₃SO₃^- (polyatomic ethane-like) and n = 1-8) were calculated and subsequently used in the analysis of the FTIR spectra of (Bu₄N)X and LiX acetonitrile solutions across a wide range of concentrations. Spectroscopic manifestations of solvation were established for all X^- examined. The results for all four anions under investigation were generalized to reveal the regularities of anion solvation by acetonitrile.

Synthesis and biological evaluation of aza-crown ether–squaramide conjugates as anion/cation symporters

Aim: Anion/cation symport across cellular membranes may lead to cell apoptosis and be developed as a strategy for new anticancer drug discovery. Methodology: Four aza-crown ether–squaramide conjugates were synthesized and characterized. Their anion recognition, anion/cation symport, cytotoxicity and probable mechanism of action were investigated in details. Conclusion: These conjugates are able to form ion-pairing complexes with chloride anions and facilitate the transmembrane transport of anions via an anion/cation symport process. They can disrupt the cellular homeostasis of chloride anions and sodium cations and induce the basification of acidic organelles in live cells. These conjugates exhibit moderate cytotoxicity toward the tested cancer cells and trigger cell apoptosis by mediating the influx of chloride anions and sodium cations into live cells.

FT-Raman spectroscopic evidences for the preferential solvation of sodium tetrafluorobrate in acetonitrile-based mixed solvents

Solutions of sodium tetrafluorobrate in acetonitrile-dimethylformamide, and acetonitrile-dimethylsulfoxide mixtures have been studied by FT-Raman spectroscopy for three solvent compositions, respectively. New bands due to solvent molecules in the first solvation shell of Na(+) were detected in the region of the O=C--N deformation and CH(3) rocking mode for amide and of the S=O and C--S stretching modes for sulfoxide. The individual solvation numbers of sodium cation in different environment were deduced. In all the cases, it is found that the sodium ion was preferentially solvated by DMF or DMSO in respective binary solvents. This result was further supported by ab initio calculations.