The Photophysics of Anthracene and Bianthryl as Indicators of Nanoscale Structural Effects in Room Temperature Ionic Liquids

Open Access
Author:
Schesser, Jacob Glenn
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
September 13, 2013
Committee Members:
  • Mark Maroncelli, Thesis Advisor
Keywords:
  • Ionic Liquids
  • Structure in Ionic Liquids
  • Electron Transfer
  • Spectroscopy
  • Bianthryl
  • Anthracene
Abstract:
The possible effects bulk structure in Room Temperature Ionic Liquids (RTILs) on the photochemistry and spectroscopic behavior of molecular solutes were investigated in relation to chemical reactions in ionic liquids. Anthracene was studied via steady state UV-visible absorption spectroscopy in a series of 1-methyl-3-alkylimidazolium bis(trifluoromethylsulfonyl)imide ([Imn,1][Tf2N]) ionic liquids with alkyl chains of n= 2,4,6,8,10, and 12. Also studied were trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P14,6,6,6][Tf2N]) and mixtures of n-hexane and [Im12,1][Tf2N]. The electron transfer reaction of 9,9’-bianthryl was studied by steady state fluorescence spectroscopy and by time-resolved fluorescence in representatives from the imidazolium series; and in [P14,6,6,6][Tf2N] and its mixtures with n-heptane. The spectroscopy of both probes in the liquids studied indicates that they are experiencing a decreased polarity in longer-chain ionic liquids, as would be expected. The trends observed do not seem to point towards significant effects from long-range structure in the liquid.