Rationally Designed Furocarbazoles as Multifunctional Aggregation Induced Emissive Luminogens for the Sensing of Trinitrophenol (TNP) and Cell Imaging

Abstract

Two structurally unique aggregation induced emission (AIE)‐active luminogens have been designed and synthesized based on the furocarbazole skeleton. Such small molecule AIEgens were designed based on forbidden planarity and engineering a twist into the scaffold to realize induction of emission in the aggregated states. The structures were fully characterized and their thermal stabilities, electronic properties, photophysical and electrochemical properties were systematically investigated. The unique twist in the molecules as evident from their X‐ray crystal structure along with the short intermolecular interactions enhances the structural rigidification and restricts detrimental π–π stacking interactions, restricting the internal rotations (RIR) accompanied by a curb of the ICT process, resulting in enhanced emission in the aggregated state. This intriguing luminescent property enabled one of the luminogens to selectively detect trinitrophenol (TNP) over other nitroaromatics in both aqueous and organic media at nanomolar concentrations. Moreover, the good photostabilities and biocompatibilities empowered both luminogens to function as fluorescent bioprobes for cancer cell imaging.

Design and Development of Axially Chiral Bis(naphthofuran) Luminogens as Fluorescent Probes for Cell Imaging

“…The nanoaggregates possess an interior polarity higher than the external surface polarity [37, 47] . Therefore, the aggregates are transformed into an aggregation‐induced locally excited state with a strained structure that is slightly destabilised energetically due to the low environmental polarity.…”

“…The nanoaggregates possess an interior polarity highert han the externals urfacep olarity. [37,47] Therefore, the aggregates are transformed into an aggregation-induced locally excited state with as trained structuret hat is slightly destabilised energetically due to the low environmental polarity.T his destabilisation results in the widening of the HOMO-LUMO energy gap, which causes the blueshifted emission (479 to 461 nm) observed for S3.M oreover,s evere aggregation resulted in restricted intramolecular rotationo ft he phenylr ing and suppressed the TICT-inducing enhanced emission in the aggregat-ed state. Further addition of water resulted in stronger emission until f w reached 90 %.…”

“…In our effort to design luminogens, we envisioned straightforwardd esign criteria that accentuate the constrained rotation of the freelyr otatable groups in the molecule through augmented intermoleculari nteractions as well as the disruption of molecular stacking in the solid state. [37] With this perspective, we considered furans that are non-emissive but if appropriately fused to the BINOL scaffold will generate chiral AIEgens with extended conjugation. The inbuiltm olecular distortion due to the axial chirality of (R)-BINOL and the presence of electron-deficient phenacyl derivatives (-COPh/CPhC(CN) 2 )a ttached to the furyl ring are likely to disrupt the p-p interactions and restrict internal rotations in the aggregated state accompanied by interrupted twisted intramolecular charge transfer (TICT).…”

A New Compound for Sequential Sensing of Picric Acid and Aliphatic Amines: Physicochemical Details and Construction of Molecular Logic Gates

“…There are numerous small molecule sensors as well to detect PA with low LOD. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Zinc oxide nanomaterials and fluorescent quantum dots were also helpful in PA detection. [57,58] The fluorescent outputs due to the sensing mechanisms were effectively used to prepare logic based devices in some cases.…”

Troger's Base Derived Butterfly Shaped Contorted AIEgens for Dead Bacterial Cell‐Imaging

“…[7][8][9][10][11][12][13] However, the emergence of a phenomenon known as Aggregation Induced Emission (AIE) contrary to the ACQ phenomenon, has been a blessing and became the sole reason for the gargantuan development in the field of optoelectronic materials. [14][15][16][17][18][19] Among the several proposed theories on designing the AIE phenomenon, restriction of the π-π stacking of the fluorophores along with the restricted intermolecular motions are the two most explored concepts to rationally design novel luminogens. However, to exploit the luminescence phenomenon of the fluorophores in both the solid and as-well-as in the solution state, researchers have started exploring dual-state emitting materials that will bridge the gap between the ACQ and AIEgenic materials.…”