Stimuli Responsive Features of Organic RTP Materials: An Intriguing Carbazole‐Cyclic Triimidazole Derivative

• Published in: Chemistry : a European journal Vol. 29; no. 38; pp. e202300930 - n/a
• Main Authors: Malpicci, Daniele, Forni, Alessandra, Botta, Chiara, Giannini, Clelia, Lucenti, Elena, Marinotto, Daniele, Maver, Daniele, Carlucci, Lucia, Cariati, Elena
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 06-07-2023
• Subjects: Carbazole; Carbazoles; Chemistry; Deactivation; Hydrogen Bonding; Hydrogen bonds; Luminescence; Phosphorescence; Room temperature; room temperature phosphorescence; Stimuli; stimuli-responsive materials; time-resolved spectroscopy; time-resolved spectroscopy; stimuli-responsive materials; room temperature phosphorescence
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202300930

Stimuli responsive luminescent materials possessing room temperature phosphorescence (RTP) are extremely desirable for various applications. The here investigated derivative of cyclic triimidazole (TT) functionalized with carbazole (Cz), namely TT‐Ph‐Cz, belongs to this class. TT‐Ph‐Cz possesses high conformational freedom resulting in rigidochromic and multi‐stimuli responsive emissive behavior. It has been isolated as MeOH‐solvated and de‐solvated forms characterized by distinctive emissive features. In particular, the solvated form, in which hydrogen bonds with MeOH inhibit competitive non‐radiative deactivation channels, possesses a higher quantum yield associated with a strong phosphorescence contribution which is preserved in DMSO/water solutions.
The triimidazole‐carbazole derivative TT‐Ph‐Cz here synthesized possesses high conformational freedom resulting in rigidochromic and multi‐stimuli responsive emissive behavior. The origin of the compound stimuli‐responsiveness is interpreted through X‐ray diffraction and DFT‐TDDFT studies. Interconversion between TT‐Ph‐Cz solvated and unsolvated phases occurs through solvent fuming and/or thermal treatment. Phosphorescent aqueous nanoaggregates are prepared from solvent/non‐solvent solutions.