Spectroscopic and Theoretical Study of (CF₃SO₂)₂N^- (TFSI^-) and (CF₃SO₂)₂NH (HTFSI)

Abstract

The vibrational properties of the TFSI- anion solvated in a polymer or in water have been studied by comparing its IR and Raman spectra with those of the HTFSI molecule. Ab initio self-consistent field Hartree−Fock calculations have also been performed on the free ion or molecule to investigate their Mulliken charges, equilibrium geometry, and internal force constants. Both experimental and theoretical approaches confirm a pronounced delocalization of the negative charge on the nitrogen and oxygen atoms and a marked double-bond character of the SNS moiety for the anion. This double-bond character is decreased for the HTFSI molecule, leading to rather distinct frequencies for some specific vibrations such as the stretching motions of the SO2 and SNS groups. The agreement between experimental and calculated spectra is much better for HTFSI than for TFSI-. Tentative explanations are proposed for this difference.

Spectroscopic and Electrochemical Analyses for Neodymium Complexes in Potassium Bis(trifluoromethylsulfonyl)amide Melts

“…The band at 740 cm −1 is ascribed to the coupled bending δ(CF 3 ) + stretching ν(S-N-S) vibration of free [TFSA] − , which shifts to a higher frequency upon binding of [TFSA] − to the metal ion. 28,29 The concentration dependences of the deconvoluted Raman spectra in the frequency range 720-780 cm …”

Raman Spectroscopy and Ab-Initio Model Calculations on Ionic Liquids

“…In addition to these studies, the structure of the bis(trifluoromethylsulfonyl)imide ([Tf 2 N] À ) anion in the liquid state has been investigated by means of IR and Raman spectroscopy and ab-initio self-consistent Hartree-Fock and DFT calculations on the free ion, aiming at a determination of the equilibrium geometry and understanding of the vibrational spectrum [137,[163][164][165]. A pronounced delocalization of the negative charge on the nitrogen and oxygen atoms was found, and a marked double-bond character of the S-N-S moiety for the anion [163,164].…”

Phase Directing Ability of an Ionic Liquid Solvent for the Synthesis of HER-Active Ni2P Nanocrystals

“…31 Additionally, PPh 3 or oxidized Ph 3 P=O species are likely coordinated to the nanocrystal surface, as indicated by the appearance of bands appearing at 1436, 1477, and 1581 cm -1 that are ascribable to phenyl C-C bond stretches. 32 No IR bands expected for coordinated OAm were observed in the Ni 2 P nanocrystals.…”