A Strongly Fluorescent Molecular Material Responsive to Physical/Chemical Stimuli and their Coupled Impact

Abstract

Molecular materials with weak but extended and pliable supramolecular interactions are versatile candidates for eliciting stimuli-sensitive optical responses. An ovel diaminodicyanoquinodimethane (DADQ) molecule,7 ,7-bis(2-(2pyridyl)ethylamino)-8,8-dicyanoquinodimethane (BPEDQ), has been synthesized and structurally characterized; it exhibits enhanced fluorescencee mission in the aggregated and solid states,c haracteristico fD ADQs.T he pyridine moieties in the molecule, in addition to the amino and cyano groups of the strongly dipolar fluorophore moiety,i nduce extensive H-bonding interactions which can impart structural integrity to the solid material;t his enables reversible crystalline-amorphous transformations triggered by mechanical grinding and solvent fuming. The concomitantf luorescencec olor and intensity switching are prominenta nd reversible. Protonation-deprotonation events induced by acidic and basic vapors also produce stark fluorescencer esponse variations; the chemical stimuli also lead to amorphization of the solid. The full cycle of chemical and physicals timuli,a nd the consequence of their individual and coupled impact on the fluorescence emission,a re illustrated using aB PEDQ-doped polymert hin film.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Exploiting N−H–π Interactions in 2‐(Dimesitylboraneyl)‐1H‐pyrrole for Luminescence Enhancement

“…[3] To achieve efficient emission in the solid state, a few strategies have been adopted that includes introducing sterically bulky or dentric substituents on the planar π-conjugated systems, [4] tuning the charge transfer properties of donor-acceptor systems [5,23,24] and introducing AIE (aggregation-induced emission) active molecules on wellknown ACQ (aggregation-caused quenching) chromophores. [3][4][5][6][7][8][9][10] Further, various kinds of intermolecular interactions like NÀ H-π, π-π, halogen bonding and hydrogen bonding are known to elicit strong emission in specific fluorophores. [6] Few classes of molecules like tetraphenylethylene, [3,7] tetraarylaminoborane, [8] hexaphenylsilole [3,9] and diaminodicyanoquinodimethane [10] derivatives showed efficient blue emission in the solid state.…”

“…[3][4][5][6][7][8][9][10] Further, various kinds of intermolecular interactions like NÀ H-π, π-π, halogen bonding and hydrogen bonding are known to elicit strong emission in specific fluorophores. [6] Few classes of molecules like tetraphenylethylene, [3,7] tetraarylaminoborane, [8] hexaphenylsilole [3,9] and diaminodicyanoquinodimethane [10] derivatives showed efficient blue emission in the solid state. In recent times, phosphorescent materials have received considerable attention due to their potential applications in displays, solid state lighting, optical storage and sensors.…”

Photophysical, electrochemical properties and flexible organic solar cell application of 7,7-bis(1-cyclopropyl carbonyl piperazino)-8,8 dicyanoquinodimethane

“…This results in divergent applications such as organic semiconductors, 4 molecular hopper crystals, 5 non-linear optical [6][7] and mechanochromic materials. 8 Di-substituted TCNQ derivatives [9][10][11] usually display enhanced fluorescence in their solids;…”

Design and Development of Distinct Tetracyanoquinodimethane Derivatives Exhibiting Dual Effect of Fluorescence and Anticancer Activity

“…[13] Size dependent optical and morphological studies revealed interesting results from simple aromatic amine substituted TCNQ's. [14][15][16] Recently, aromatic (benzene) amine moieties as substituents on TCNQ resulting in cyclized structures at δ + carbon has evolved in high fluorescent diaminodicyanoquinones, with 90 % quantum yields. [17] High aspect ratio nanowires of Ag/AgTCNQ synthesized on silver fabric for the first time have shown antimicrobial property.…”

“…Mostly, TCNQ derivatives have shown enhanced emission in solid/aggregated/thin film state rather than their solutions, probably due to the strong zwitterion and push‐pull nature, [12–13] supramolecular assembly, [10–13] restricted intra molecular rotations [12] and non‐radiative geometrical relaxations in excited states [13] . Size dependent optical and morphological studies revealed interesting results from simple aromatic amine substituted TCNQ's [14–16] . Recently, aromatic (benzene) amine moieties as substituents on TCNQ resulting in cyclized structures at δ + carbon has evolved in high fluorescent diaminodicyanoquinones, with 90 % quantum yields [17] …”