Abstract
Molecular materials with weak but extended and pliable supramolecular interactions are versatile candidates for eliciting stimuli-sensitive optical responses. A novel diaminodicyanoquinodimethane (DADQ) molecule, 7,7-bis(2-(2-pyridyl)ethylamino)-8,8-dicyanoquinodimethane (BPEDQ), has been synthesized and structurally characterized; it exhibits enhanced fluorescence emission in the aggregated and solid states, characteristic of DADQs. The pyridine moieties in the molecule, in addition to the amino and cyano groups of the strongly dipolar fluorophore moiety, induce extensive H-bonding interactions which can impart structural integrity to the solid material; this enables reversible crystalline-amorphous transformations triggered by mechanical grinding and solvent fuming. The concomitant fluorescence color and intensity switching are prominent and reversible. Protonation-deprotonation events induced by acidic and basic vapors also produce stark fluorescence response variations; the chemical stimuli also lead to amorphization of the solid. The full cycle of chemical and physical stimuli, and the consequence of their individual and coupled impact on the fluorescence emission, are illustrated using a BPEDQ-doped polymer thin film.
Original language | English |
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Pages (from-to) | 4754-4759 |
Number of pages | 6 |
Journal | Chemistry - An Asian Journal |
Volume | 14 |
Issue number | 24 |
DOIs | |
State | Published - 13 Dec 2019 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Funding
Financial support from the DST, New Delhi (J. C. Bose Fellowship) and infrastructure support from the DST (PURSE and FIST programs), the UGC, New Delhi (CAS and UPE programs) and the School of Chemistry, University of Hyderabad are acknowledged with gratitude. PS thanks the SERB, DST, for a National Post-doctoral Fellowship.
Funders | Funder number |
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Department of Science and Technology, Ministry of Science and Technology, India | |
University Grants Committee | |
Science and Engineering Research Board |
Keywords
- amorphous-crystalline transformation
- fluorescence
- molecular crystal
- protonation
- stimuli-responsive