Investigation of ionic liquids under Bi‐ion and Bi‐cluster ions bombardment by ToF‐SIMS

Abstract

A systematic study of five different imidazolium-based room temperature ionic liquids, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium nitrate, 1-butyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide were carried out by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in positive and negative ion mode. The compounds were measured under Bi-ion and Bi-cluster ions (Bi(2-7)(+), Bi(3, 5)(2+)) bombardment, and spectral information and general rules for the fragmentation pattern are presented. Evidence for hydrogen bonding, due to high molecular secondary cluster ions, could be found. Hydrogen bonding strength could be estimated by ToF-SIMS via correlation of the anionic yield enhancement with solvent parameters.

Investigation of 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide under Binx+ cluster ion bombardment

“…A more detailed study about the interaction of different ionic liquids with bismuth primary ion cluster will be presented elsewhere. [18] Changing to cluster primary ions may not always be beneficial, due to a 20-30% decrease in secondary ion yield for the cation www.interscience.wiley.com/journal/sia and the anion using Bi 2 + or Bi 3 + . However, at a primary ion dose density of 1 × 10 10 ions cm −2 the measuring time is low and the sensitivity for high molecular cluster is high to obtain high-quality mass spectra.…”

“…[24,25] In our study on the interaction of cluster primary ions with ionic liquids, we find a similar behavior. [18] The yield of the intact cation or anion, respectively, decreases by changing from Bi 1 + to Bi 2 + or Bi 3 + . By a further increase of the cluster size (and charge, e.g.…”

“…[17,18] Further, they can be regarded as hydrogen-bonded supramolecules [19] providing an organic bulk material with large chain molecules but weaker bonded than in solid polymers. The ability to analyze this material in substance enables one to study the enhancement in secondary ion yield without interferences from substrate wafers, such as silicon, aluminium and silver, and from different sample preparation conditions.…”

Zwitterionic clusters with dianion core produced by electrospray ionisation of Brønsted acidic ionic liquids

“…The occurrence of such clusters is not restricted to ESI and is observed also with other ionisation methods. [31][32][33] Also, this type of cluster ion is not unique to the ILs, it is in fact commonly observed for ionic, salt-like species and there have been earlier studies by this group on non-IL cluster ions of this type. [34][35][36] In tandem mass spectrometry experiments a cluster ion of choice is separated from others and allowed to dissociate.…”

Atomic spectrometry update. Industrial analysis: metals, chemicals and advanced materials

“…An investigation by Holzweber et al into the analysis of five different ionic liquids using TOF-SIMS was therefore timely. 120 A range of ionic liquids was analysed under Bi-ion and Bi-cluster ion bombardment. Some very nice mass spectra of these compounds were presented, together with proposed general rules for understanding their fragmentation.…”