Organic materials characterized by multi-component emissive behavior including RTP features are extremely desirable for various applications. Frequently, long lasting emissions of solids are originated from intermolecular interactions whose role is far from being fully understood. In this context, positional isomers with similar molecular properties but different packing arrangement can be a useful tool to get a deeper comprehension of the mechanisms involved in the solid state emissive behavior. Here, the results obtained on two derivatives of cyclic triimidazole (TT) functionalized with a pyridin-2-yl or 4-yl ethynyl group are presented and interpreted through spectroscopical, structural and computational studies. The two isomers are hardly emissive in solution but become good emitters in blended PMMA films displaying almost overlapping fluorescence and phosphorescence. In solid-state, two additional lower energy phosphorescences are activated through the establishment of either π-π stacking or synergic π-π/hydrogen bond interactions. Stronger aggregated RTP features are observed in the pyridin-2-ylethynyl derivative which displays tighter π-π stacking interactions.

Role of molecular packing in RTP features of positional isomers: The case study of triimidazo-triazine functionalized with ethynyl pyridine moieties

Malpicci D.;Cariati E.
;
Lucenti E.;Marinotto D.;Botta C.;Forni A.
2025

Abstract

Organic materials characterized by multi-component emissive behavior including RTP features are extremely desirable for various applications. Frequently, long lasting emissions of solids are originated from intermolecular interactions whose role is far from being fully understood. In this context, positional isomers with similar molecular properties but different packing arrangement can be a useful tool to get a deeper comprehension of the mechanisms involved in the solid state emissive behavior. Here, the results obtained on two derivatives of cyclic triimidazole (TT) functionalized with a pyridin-2-yl or 4-yl ethynyl group are presented and interpreted through spectroscopical, structural and computational studies. The two isomers are hardly emissive in solution but become good emitters in blended PMMA films displaying almost overlapping fluorescence and phosphorescence. In solid-state, two additional lower energy phosphorescences are activated through the establishment of either π-π stacking or synergic π-π/hydrogen bond interactions. Stronger aggregated RTP features are observed in the pyridin-2-ylethynyl derivative which displays tighter π-π stacking interactions.
2025
Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" - SCITEC - Sede Secondaria Milano - Via C. Golgi
Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" - SCITEC
Aggregation induced enhanced emission
Excitation dependent luminescence
Nitrogen rich aromatic compounds
Organic room temperature phosphorescence
Supramolecular interactions
File in questo prodotto:
File Dimensione Formato  
Next Materials 2025, 7, 100440.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 1.93 MB
Formato Adobe PDF
1.93 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/525926
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact