Comparison of Dansylated Aminopropyl Controlled Pore Glass Solvated by Molecular and Ionic Liquids

Abstract

We compare how (i) four ionic liquids (ILs) (1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpy][Tf2N]), and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P(C6)3C14][Tf2N])) and (ii) two conventional molecular liquids (methanol and 1-octanol) solvate/wet luminescent organic moieties that are covalently attached to the surface of silica controlled pore glass (CPG). A series of aminopropyl CPG particles that have been covalently tagged with the solvatochromic fluorescent probe group dansyl were used in this study. The results demonstrate that ILs solvate/wet the silica surface differently in comparison to molecular liquids (MLs). Specifically, when comparing ILs and MLs that appear to solvate the free probe, dansylpropylsulfonamide (DPSA), equally in solution, we find that ILs do not solvate/wet the silica surfaces as well as the corresponding MLs. The cation component in these ILs is the significant factor in how the ILs solvate/wet silica surfaces. Solvation/wetting of surface-bound species at a silica surface depends on the cation size. Chlorosilane end-capping of the surface silanol and amine residues attenuates the cation's affects.

Activity Coefficients at Infinite Dilution of Organic Compounds in Trihexyl(tetradecyl)phosphonium Bis(trifluoromethylsulfonyl)imide Using Inverse Gas Chromatography

“…The modified LFER model proposed by Sprunger and co-workers was used to characterize the nature of solute interactions with this ionic liquid. The cation-specific coefficients were estimated using the partition coefficients of 45 organic compounds calculated at 298.15 K. 19 The ionic liquid was further dried under vacuum for 4 days at 343 K to remove trace moisture. The water mass fraction of the ionic liquid, as determined by coulometric Karl Fischer titration, was (57 ( 5) · 10 -6 .…”

Ionic Liquids Can Permanently Modify Porous Silicon Surface Chemistry

“…[3 L 2 OHpropN 111 ][Tf 2 N] was prepared by ion‐exchange using the commercial quaternary ammonium salt (3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride (Sigma–Aldrich) and [bmim][PF 6 ] and [bmim][BF 4 ] were sourced from IoLiTec Ionic Liquids Technologies (Tuscsaloosa, AL). All other ionic liquids were prepared by following methods and precautions reported by us previously . Ionic liquids were dried at 60 °C under vacuum overnight on a Schlenk line using a 22‐gauge needle piercing the PTFE/silicone septum of a sealed borosilicate glass EPA vial containing the ionic liquid.…”

“…All other ionic liquids were prepared by following methods and precautions reported by us previously. [49,[54][55][56] Ionic liquids were dried at 60 8Cu nder vacuum overnight on aS chlenk line using a2 2-gauge needle piercing the PTFE/silicone septum of as ealed borosilicate glass EPAv ial containing the ionic liquid.…”

Wettability by Ionic Liquids

“…Furthermore, the extremely low vapor pressure of ILs makes it possible to study microscopic insights of contact between ILs and underlying surfaces by using scanning electron microscopy (SEM), although the solvation of four ILs on porous glass has been reported by using fluorescence spectroscopy . When a droplet of IL (dimethylbis(β‐hydroxyethyl)ammonium methanesulfonate) is drawn off a superhydrophobic surface with staggered rhombus posts, tiny IL droplets with ≈3 μm diameter can be observed on the top of every post ( Figure a).…”