Solvation of AgTFSI in 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid investigated by vibrational spectroscopy and DFT calculations

Abstract

In this paper we investigate the solvation of silver bis(trifluoromethylsulfonyl)imide salt (AgTFSI) in 1‐ethyl‐3‐methylimidazolium TFSI [EMI][TFSI] ionic liquid by combining Raman and infrared (IR) spectroscopies with density functional theory (DFT) calculations. The IR and Raman spectra were measured in the 200–4000 cm−1 spectral region for AgTFSI/[EMI][TFSI] solutions with different concentrations ([AgTFSI] <0.2 mole fraction). The analysis of the spectra shows that the spectral features observed by dissolution of AgTFSI in [EMI][TFSI] solution originate from interactions between the Ag+ cation and the first neighboring TFSI anions to form relatively stable Ag complexes. The ‘gas phase’ interaction energy of a type [Ag(TFSI)3]2− complex was evaluated by DFT calculations and compared with other interionic interaction energy contributions. The predicted spectral signatures because of the [Ag(TFSI)3]2− complex were assessed in order to interpret the main IR and Raman spectral features observed. The formation of such complexes leads to the appearance of new interaction‐induced bands situated at 753 cm−1 in Raman and at 1015 and 1371 cm−1 in IR, respectively. These specific spectral signatures are associated with the ‘breathing’ mode and the S–N–S and S–O stretching modes of the TFSI anions engaged in the complex. Finally, all these findings are discussed in terms of interaction mechanisms enabling the electrodeposition characteristics of silver from AgTFSI/[EMI][TFSI] IL‐based electrolytic solutions. Copyright © 2015 John Wiley & Sons, Ltd.

Atomistic Insight into Changes in the Vibrational Spectrum of Ionic Liquids under External Electric Field

“…Brela et al 18 performed extensive analysis of the HB network and its effect on vibrational spectra in a typical aprotic IL (1ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide ([Emim][TFSI]) by using ab initio and classical MD simulations. Furthermore, the molecular interactions of a Cu-based metalorganic framework with a confined imidazolium-based IL were investigated through vibrational spectroscopy study by using the method combined DFT and experiment 19 , and the solvation of AgTFSI in [Emim][TFSI] IL was investigated by vibrational spectra and DFT calculations 20 . Recently, the vibrational spectra of ring hydrogen atoms of imidazolium-based ILs with [Bmim] + cations paired with Cl − , Br − and [BF4] − anions were studied by using classical MD simulations with different force fields and DFT methods using the MD results for liquid structures in the QM/MM (quantum mechanics/molecular mechanics) framework 21 .…”

Dendritic Network Implementable Organic Neurofiber Transistors with Enhanced Memory Cyclic Endurance for Spatiotemporal Iterative Learning

“…The stretching vibrations of the SNS and SO 2 bonds of TFSI anions distinctly shifted from 1063 and 1143 cm −1 to 1017 and 1115 cm −1 , respectively, during the oxidation process, indicating weakening of the bond stretching stabilized by counter charges. [ 30,31 ] In addition, two split SO 2 peaks at 1112 and 1136 cm −1 , which correspond to the transoid structure of TFSI, newly appeared in the spectrum of the oxidized P3HT (see Figure S6 in the Supporting Information). Given that the transoid structure of the TFSI anion preferably interacts with counter ions because of the lower steric hindrance resulting from the exposure of its negatively charged N atom, this result is evidence that TFSI anions interacted with positively charged species.…”

Overcoming Electrochemical Instabilities of Printed Silver Electrodes in All-Printed Ion Gel Gated Carbon Nanotube Thin-Film Transistors

“…Anodic corrosion: ,, Oxidation of silver: Ag → Ag + + e – . Strong interaction between Ag + and [TFSI – ]. Metal dissolution via formation of [Ag...TFSI] complexes and then solvation of [Ag...TFSI] into [Ag...TFSI 3 ] 2– . …”

“…Silver electrodes react with TFSI – anions at anodic polarization when silver electrodes are covered with ion gel. Consequently, [Ag­(TFSI) 3 ] 2– complexes are gradually formed and diffuse back into the ion gel with a slower diffuse rate than TFSI – anions, resulting in p-type SWCNT TFTs with relatively large hysteresis. Besides, TFTs fully covered by ion gel do not show any n-type field-effect conduction (Figure S11b) probably because silver source/drain electrode surface present thin silver oxides with a high work function …”