Functionalized pyrene‐based AIEgens: synthesis, photophysical characterization and density functional theory studies. (29th July 2019)

• Record Type: Journal Article
• Authors: Mohan, Makesh; James, Juliya; Satyanarayan, M.N.; Trivedi, Darshak R.
• Is Part Of: Luminescence. Volume 34:Number 7(2019)
• Page Start: 715
• Page End: 723
• Publication Date: 2019-07-29
• Subjects: Luminescence -- Periodicals; Bioluminescence -- Periodicals; Chemiluminescence -- Periodicals; Luminescence -- Periodicals; 535.35
• DOI: 10.1002/bio.3665
• Languages: English
• ISSNs: 1522-7235

Abstract

Abstract: Three new pyrene‐based derivativesP1, P2 andP3 with a substituted pyrazole were designed, synthesized and characterized using standard spectroscopic techniques. Ultraviolet–visible (UV–vis) spectroscopic studies forP1–P3 uncovered a finite bathochromic shift of the molecules in solvents of varying polarity. Photoluminescence (PL) studies revealed the significant fluorescence emission of all molecules in higher polar solvents such as MeOH and dimethylformamide (DMF). Fluorescence quantum yield studies demonstrated the importance ofP3 possessing cyanofunctionality for imparting higher emission with a quantum yield of 0.36%. Ratiometric studies performed in a tetrahydrofuran (THF)/H2 O mixture indicated fluorescence enhancement with increasing overall percentage of water, confirming the aggregation‐induced emission effect. Cyclic voltammetry study of moleculesP1–P3 revealed an irreversible oxidation peak and the band gaps were calculated to be 2.26 eV forP1 and 2.31 eV forP2 andP3 respectively. Density functional theory (DFT) studies performed on moleculesP1–P3 validate the structure correlation of the molecules. Theoretically estimated highest occupied molecular orbital( HOMO), lowest unoccupied molecular orbital (LUMO) and bandgap correlated well with the experimental values. Furthermore, time‐dependent (TD)DFT showed that the major contribution for the electronic transitions occurring in the system was governed by HOMO‐1 and LUMO+1 orbitals.