α-Cyanostilbene: A Multifunctional Spectral Engineering Motif

The remarkable photophysical phenomenon of aggregation-induced emission offers excellent strategies to obtain the molecular materials possessing unique spectral signatures such as high fluorescence intensity, excellent quantum yield, large Stokes shift...

Fabrication of deoxycholic acid tethered α-cyanostilbenes as smart low molecular weight gelators and AIEE probes for bio-imaging

Four novel deoxycholic acid tethered α-cyanostilbenes were designed, synthesized and characterized using detailed spectroscopic analysis. The synthesized deoxycholic acid tethered α-cyanostilbene derivatives formed stable gels with a variety of solvents, such as xylene, toluene, mesitylene, decane, dodecane etc. The stable gels showed lamellar sheet type structures stacked over each other, consisting of entangled fibres as evident from SEM, TEM and Fluorescence Microscopy images; The synthesized compounds exhibited AIEE behaviour in H₂O/THF mixture, with the maximum emission observed in 70% H₂O/THF fraction along with a bathochromic shift. A solvent thickening experiment was perform to establish the mechanism of AIEE and the AIEE property was explored for bacterial bio-imaging. The synthesized derivatized steroids proved their potential as multifunctional organic materials.

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

The synthesis, photophysical investigations, and organogel formation of pyrene-phenyl acrylonitriles (1-6) bearing mono-, di-, and trichiral and racemic substitutions were studied. The molecules self-assemble in water and show remarkable emission wavelength and intensity changes associated with distinct color changes. Cryo-scanning electron microscopy (Cryo-SEM) images show the formation of uniform nanoaggregates for the monosubstituted derivatives and network-like structures for di- and trisubstituted derivatives. The favorable π-π stacking ability of the coplanar pyrene ring, steric restrictions due to the cyano group, and beneficial noncovalent interactions from the citronellol moiety allow the molecules to form excellent organogels with fibrous and twisted ribbon morphology for the racemic and chiral derivatives. The organogels based on small molecules could be of high relevance for potential investigations involving soft biological matter.

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

Pyridyl acrylonitrile without traditional auxiliary groups form stable organogels in ethanol. The addition of a second non-gelating cyanostilbene component results in a more stable two-component gel. Single crystal X-ray data reveal the influence of C-H⋅ ⋅ ⋅N, C-H⋅ ⋅ ⋅π, and π-π interactions in the formation of organogels. The morphology of the xerogels was studied by using SEM, which showed the self-assembly of molecules to fibers and sheet-like structures, and phase differences upon the gel formation and the structural phase characterization was measured using powder XRD. Exposure of the organogels to acidic (TFA) vapors results in distinct color changes and loss of gelation properties, thus highlighting the potential of these gels in sensing. The results represent a rare example of two-component organogels using two different cyanostilbene units and show that functional two-component organogels can be formed by utilizing the synergistic effects of the individual components.

Branching effect on triphenylamine-CF3 cyanostilbenes: enhanced emission and aggregation in water

Aggregation-induced emission and gelation behavior of symmetric and asymmetric triphenylamines

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

Efficient organogel formation with CF₃ substituted styrylpyrenes.