Article Metrics


Online attention

Structure and vibrational features of the protic ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-ene-8-ium bis(trifluoromethanesulfonyl)amide, [DBUH][TFSI]

DOI: 10.1016/j.molliq.2021.117981 DOI Help

Authors: Alessandro Triolo (Consiglio Nazionale delle Ricerche, (ISM-CNR)) , Annalisa Paolone (Consiglio Nazionale delle Ricerche) , Angelo Sarra (Consiglio Nazionale delle Ricerche) , Francesco Trequattrini (Consiglio Nazionale delle Ricerche; Sapienza University of Rome) , Oriele Palumbo (Consiglio Nazionale delle Ricerche) , Giovanni Battista Appetecchi (ENEA, SSPT-PROMAS-MATPRO Technical Unit) , Fabrizio Lo Celso (Consiglio Nazionale delle Ricerche, (ISM-CNR); Università di Palermo) , Philip A. Chater (Diamond Light Source) , Olga Russina (Consiglio Nazionale delle Ricerche, (ISM-CNR); University of Rome Sapienza)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Molecular Liquids , VOL 108

State: Published (Approved)
Published: October 2021
Diamond Proposal Number(s): 27222

Abstract: The Protic Ionic Liquid (PIL) formed by neutralization of the super-strong base 1,7-diazabicyclo[5.4.0]undec-7-ene (DBU) with the super-strong acid bis(trifluoromethanesulfonyl)-imide (TFSI), indicated as [DBUH][TFSI], has been investigated. Its chemical physical properties and structural features have been explored using a synergy of experimental and computational tools. Molecular Dynamics-rationalised X-ray diffraction patterns highlight the major role played by hydrogen bonding (HB) in affecting morphology in this PIL. A comparison between HB features in this and in related PILs has been presented, on the base of far-IR experiments and DFT analysis. Indications of a weaker HB interaction in [DBUH][TFSI] in comparison with [DBUH][TfO], consistently with their ΔpKa difference, have been observed and rationalised in terms of geometrical properties of the main conformers contributing to the experimental spectra. In the liquid phase of [DBUH][TFSI] a particularly large conformational disorder is observed and the corresponding large dispersion of the frequencies of the HB stretching modes leads to a broad absorption band without a well defined peak. On the contrary, well detectable HB related absorptions are observable in the solid phase of [DBUH][TFSI] and at all temperatures in [DBU][TfO], where less configurational disorder occurs.

Journal Keywords: Protic Ionic Liquid; hydrogen bonding; X-ray scattering; Far-ir spectroscopy; Molecular Dynamics; DFT calculation

Subject Areas: Chemistry, Physics

Instruments: I15-1-X-ray Pair Distribution Function (XPDF)

Other Facilities: AILES at Soleil

Added On: 02/11/2021 09:24

Discipline Tags:

Molecular Physics Physics Physical Chemistry Chemistry

Technical Tags:

Scattering Total Scattering