Star‐Shaped Quaternary Alkylammonium Polyhedral Oligomeric Silsesquioxane Ionic Liquids

Abstract

New star‐shaped quaternary ammonium (QA) polyhedral oligomeric silsesquioxane (POSS) salts based on octakis(tetraalkylammonium) POSS cations bearing alkyl chains of different length (methyl, n‐butyl, and n‐octyl) and differently polarizable anions [iodide, bis(trifluoromethylsulfonyl)imide, and ibuprofen] have been synthesized and characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) investigations show that the nature of the cation plays a key role in determining the thermal behavior of QA POSS salts featuring the longest alkyl chains, whereas the influence exerted by anions becomes relevant for those bearing short and medium alkyl chains. All the QA POSS salts display amorphous behavior and, with the exception of octakis(trimethylpropylammonium)‐ and octakis(tri‐n‐butylpropylammonium)octasilsesquioxane iodide, may be classified as ionic liquids. Dynamic contact‐angle studies reveal their hydrophilic attitude owing to the preferential orientation of the tetraalkylammonium groups at the film–water interface.

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s

“…148 The 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 The aforementioned star-like oligo(ionic liquid)s are inorganic-organic compounds in terms of their global chemical composition. The reports on fully organic star-like poly(ionic liquid)s in the literature are scarce.…”

“…147,148,149,150,151,152,153,154,155,156,157,158,159,160 Based on the range of molecular masses involved, these compounds can be regarded as OIL compounds. Their molecular weight depends on the length of the spacer and the type of the ionic group and starts from 1338 g/mol for derivatives with one arm 147 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 temperature of 172°C.…”

“…Among them, the most explored are aprotic cationic POSS-IL, whereas the literature on protic POSS-IL of this structure is absent to the best of our knowledge. The IL-groups are represented by terminal aliphatic tertiary amines with various lengths of the aliphatic substituent at the nitrogen atom,147,148,149,151,156,158 and also 1-substituted imidazole groups 150,153,154,155,159,161,162. The classical anionic groups are usually used as counterions (Figure 2).The charge density is regulated either by synthesis of monosubstituted POSS with varied spacer lengths, or by the degree of quaternization of these amino-containing substituents in the case of octasubstituted POSS 147,149,153,154,155.…”

Highly untangled multiwalled carbon nanotube@polyhedral oligomeric silsesquioxane ionic hybrids: Synthesis, characterization and nonlinear optical properties

“…In the course of our studies regarding the synthesis and properties of POSS tetraalkylammonium (POSS-QAs) ILs [16][17][18], we have found that ''pendant functionalized'' monosubstituted R 7 -POSS-NMe 3 + (R = isooctyl) ILs, in contrast with conventional ones, display a chemical behavior determined by the bulky amphiphilic cation. This, being characterized by a hydrophobic organic corona on the ''OASiAO'' siloxane core and a hydrophilic ammonium pendant group, exhibits a cationic surfactant behavior in organic solvents and a remarkable extraction capability of various polyanions from aqueous solution.…”

New Polyhedral Oligomeric Silsesquioxanes-Based Fluorescent Ionic Liquids: Synthesis, Self-Assembly and Application in Sensors for Detecting Nitroaromatic Explosives

“…Ionic liquids (ILs), which have been recognized as a novel class of synthetic materials, have melting points below 100 °C [1,2,3]. With increasing demand for advanced materials, the development of novel ILs has been increasingly explored due to their unique properties [4], which include high ionic conductivity [5], high thermal stability, non-flammability, negligible vapor pressure, and a wide electrochemical stability window [6,7]. Due to the above advantages, ILs have been applied as functional materials in many chemical and industrial fields including fuel cells and lithium batteries [8], particular as catalysis solvents, capacitors, and electrochemical sensors [3].…”