Cyclic phosphonium ionic liquids

Abstract

SummaryIonic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners.

Molecular features contributing to the lower viscosity of phosphonium ionic liquids compared to their ammonium analogues

“…127 The first analogue, butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Fig. 8a) and butylmethylphospholanium bis(trifluoromethylsulfonyl)imide (Fig.…”

“…Thus, the higher flexibility of bond angles and dihedral angles in phosphonium based ILs should enhance the flexibility of the alkyl chain ring in the six-membered ring more strongly than in the five-membered ring which affects viscosity, as well. Indeed, the phosphonium compound possesses the lower viscosity than the ammonium compound in the second analogue 127 which highlights the important role of bond angle and dihedral angle flexibility for the lower viscosity in tetraalkylphosphonium ILs and also the interplay of the different molecular Fig. 7 Comparison of the TPSS-D3(RI)/6-31++G** dihedral angle energy potential surface of tetraalkylammonium cations (blue) and tetraalkylphosphonium cations (red).…”

“…Lewis structure of two phosphonium/ammonium analogues and viscosity at 25 • of the ILs with bis(trifluoromethylsulfonyl)imide as common anion [127][128][129]. 4 Summary and ConclusionsThe lower viscosity of tetraalkylphosphonium based ILs compared to tetraalkylammonium based IL analogues have been investigated by static quantum chemistry calculations and classical force field simulations.…”

Phosphonium salts and P-ylides

“…5). 128 These compounds proved slightly less conductive than their cyclic ammonium congeners. Warner and co-workers described a new class of PILs obtained from anionic fluorescein derivatives paired to phosphonium cations 129 These PILs were fluorescent probes for highly selective and sensitive detection of albumins.…”

Polycarbonate/1‐(2‐hydroxyethyl)‐2,3‐dimethylimidazolium chloride composite membranes and short‐range chain mobility analysis

“…The main characteristics of IL comprise low flammability, high thermal and chemical stability, high ionic conductivity, and potential to be used as solvent . Among the IL are, for example, ammonium, pyridinium, phosphonium, and imidazolium salts. Imidazolium and its salts are one of the most studied ILs, like N ‐vinilimidazolinium, 1‐ethyl‐3‐methylimidazolium, 1‐butyl‐3‐methylimidazolium, and 1‐octyl‐3‐methylimidazolium .…”