Photophysical studies of pyrenyl cyanostyrenes: effect of trifluoromethyl substitution on gelation

Abstract

Efficient organogel formation with CF3 substituted styrylpyrenes.

One‐ and Two‐Component Organogels Containing Cyanostilbene without any Auxiliary Substituents

“…Cyanostilbenes bearing auxiliary linkers such as alkyl chains, glycol units, amide units were known to form stable organogels . Importantly, cyanostilbenes also form stable organogels with smaller auxiliary groups such as trifluoromethyl substituents . Surprisingly, stilbene 3 (14 mg in 600 μL of ethanol) bearing a pyridine ring and devoid of the general auxiliary groups forms a gel in ethanol with a critical gelation concentration of 8.5 mg/mL) (Figure b (inset) & Figure S6).…”

α-Cyanostilbene: a multifunctional spectral engineering motif

“…Thus, we developed a series of organogelators based on the polyaromatic hydrocarbons such as anthracene ( SK22–SK24 ) and pyrene ( SK25–SK27 ) derivatized α-CS π-frameworks and functionalized the other end with o -, m -, and p -CF 3 -substituted phenyl units. 111,112 Nevertheless, marginal differences were noted in the SLE behavior due to the weak electron-deficient CF 3 substitution, where increasing the CF 3 count ameliorated the gelation tendency. Upon cooling, these molecules organized into self-assembled nanostructures in t -BuOH through non-covalent F⋯F/H/π and N⋯H/π interactions.…”

Aggregation-Induced Emission and Organogels with Chiral and Racemic Pyrene-Substituted Cyanostyrenes

“…29−35 Recently, we demonstrated the formation of lowmolecular-weight organogels with AIE luminogens bearing pyrene and −CF 3 moieties. 16 AIE materials incorporating chiral substituents such as natural product analog citronellol have gained attention due to the broad relevance of chirality in the biological supramolecular assemblies and general sensing applications. 36−44 We hypothesized that the introduction of alkyl chains in the styrene scaffold would enable the formation of stable aggregates by synergistic noncovalent interactions.…”

“…Organic π-conjugated materials with aggregation-induced emission (AIE) properties have attracted robust interest because of their potential applications in optoelectronic and biological investigations. − α-Cyanostilbenes are one of the attractive molecular systems exhibiting the unique aggregation-induced enhanced emission phenomenon and are a subject of several investigations into physical and biological applications. − The unusual self-assembly behavior of suitably substituted cyanostilbene derivatives promoted investigations on low-molecular-weight organogel formation. − The fabrication of such low-molecular-weight tunable luminescent soft materials has attracted many researchers due to their potential applications in sensing, drug delivery, tissue engineering, and so forth. , For organogel formation, favorable noncovalent interactions such as H-bonding, π–π interactions, and hydrophobic forces play an essential role. , Pyrene, an electron-rich planar conjugated aromatic molecule having a long lifetime and excellent fluorescence quantum efficiency, is a potential candidate for organic electronics and molecular self-assembly apart from its role as a probe for biological applications. − …”

“…Pyrene derivatives with their favorable large π-surface have therefore been explored for the formation of organogels by incorporating suitable functional groups aiding in intermolecular interactions. The substituents include cholesterol, alkyl or glycol chains, amides, amino acids, peptides, imines, among others. − Recently, we demonstrated the formation of low-molecular-weight organogels with AIE luminogens bearing pyrene and −CF 3 moieties . AIE materials incorporating chiral substituents such as natural product analog citronellol have gained attention due to the broad relevance of chirality in the biological supramolecular assemblies and general sensing applications. − We hypothesized that the introduction of alkyl chains in the styrene scaffold would enable the formation of stable aggregates by synergistic noncovalent interactions.…”