Naphthalene‐Functionalized, Photoluminescent Room Temperature Ionic Liquids Bearing Small Counterions

Abstract

Obtaining π-conjugated room temperature ionic liquids (RTILs) is difficult because of the relatively strong π-π interaction among the π-moieties. Existing strategies by using bulky counterions greatly hindered further property optimization and potential applications of these intriguing functional fluids through simple ion exchange. Herein, four naphthalene-functionalized, π-conjugated RTILs with small counterions (Br(-) ) have been facilely synthesized with high yields. Our strategy is to attach branched alkyl chains to the cationic backbone of the target compounds (2 a-d), which effectively tune inter- and intramolecular interactions. Compounds 2 a-d have satisfactory thermal stability (up to 300 °C) and low melting points (<-19 °C). Rheological measurements revealed the fluid character of 2 a-d, whose viscosity decrease with the increase of the alkyl chain length and temperature. The presence of the π-conjugated naphthalene moiety imparts 2 a-d photoluminescent properties in bulk solutions. Moreover, the absence of strong π-π stacking among the naphthalene units in solvent-free states enables them to be used as a new generation of photoluminescent inks.

Aggregation‐Induced Emission of EuIII Complexes Balanced with Bulky and Amphiphilic Imidazolium Cations in Ethanol/Water Binary Mixtures

“…Recently,w eh ave successfully synthesized as eries of imidazolium-based room-temperature ionic liquidse ach of which bears an aphthyl andb ranched alkyl chain (Scheme 1, 1Br-4Br). [28] By using the imidazolium cation 1-4 as the counterions, we report in this work the preparation of an ew type of lanthanide complexes with Eu III as the central ion and thenoyltrifluoroacetone (tta) as the ligand (1Eu(tta) 4 -4Eu(tta) 4 , Scheme1). The uniques tructure of the imidazolium cation, especially 1,m akes the complex amphiphilic.…”

Photoluminescent Honeycomb Structures from Polyoxometalates and an Imidazolium‐Based Ionic Liquid Bearing a π‐Conjugated Moiety and a Branched Aliphatic Chain

“…[4] When CS 2 was replaced by CHCl 3 ,ahoneycombf ilm with well-orderedp ores could also be obtained ( Figure S1 in the Supporting Information). [49] Upon the formation of complex, it was found that the absorption around2 80 nm decreases while that above 300 nm increases. When the concentration is lower (down to 1mgmL À1 ), the film becomes quite fragile.…”

“…IL1 has as trong absorption peak around2 80 nm and an absorption band between3 00-350nm, whichi sc onsistent with our previousr eports. [49] Upon the formation of complex, it was found that the absorption around2 80 nm decreases while that above 300 nm increases. As the absorption of {Mo 72 Fe 30 }d ecreasesc ontinuouslyw ith increasing wavelength, this bathochromic shift of the complex cannot be simply interpreted by the overlapping of the absorptions of IL1 and {Mo 72 Fe 30 }.…”

“…[49] The structures of selected members are given in Scheme1 (IL1, IL2). [49] The structures of selected members are given in Scheme1 (IL1, IL2).…”

“…Recently,w er eported the successful synthesis of as eries of naphthalene-functionalized, imidazolium-basedr oom temperature ionic liquids which bear branched aliphatic chains. [49] The structures of selected members are given in Scheme1 (IL1, IL2). As IL1 (or IL2)h as an imidazolium group in the middle, it is thus possible to complex with POMs through electrostatic interactions (Scheme 1).…”