Synthesis and photophysical investigations of pyridine-pyrazolate bound boron(III) diaryl complexes.
- Resource Type
- Article
- Authors
- Javaid, Rashid; Rehman, Aziz Ul; Ahmed, Manan; Karouei, Mohammad Hashemi; Sayyadi, Nima
- Source
- Scientific Reports. 10/1/2022, Vol. 12 Issue 1, p1-11. 11p.
- Subject
- *BORON
*TIME-resolved spectroscopy
*STOKES shift
*CHEMICAL stability
*QUANTUM efficiency
*CHARGE transfer
*ELECTRON donors
- Language
- ISSN
- 2045-2322
This study presents the design and synthetic pathway of unsymmetric ligands based on pyridine-pyrazolate scaffold with Donor–Acceptor (D–A) molecular arrays and their boron complexes to achieve a large Stokes shift. Intermolecular charge transfer (ICT) triggered by the uneven molecular charge distribution from electronically dense pyrazolate (donor) part of the ligands to electron-deficient boron centre (acceptor) resulted in a mega Stokes shift up to 263 nm for selected compounds while retaining the characteristic quantum efficiency and chemical stability. The photophysical properties of derivatization of pyrazolate group in the pyridine-pyrazolate scaffold of diaryl boron complexes were explored based on UV–Visible, steady-state and time-resolved fluorescence spectroscopy. An interesting dual emission along with quenching behaviour was also observed for 2-(6-methoxynaphthelene) 5-(2-pyridyl) pyrazolate boron complex (P5) due to the formation of a twisted intermolecular charge transfer (TICT) state from a locally excited (LE) state rendering it a potential candidate for sensing applications based on H-Bond quenching. In addition, the extended excited state lifetime of the reported compounds compared to classical boron-dipyrromethene (BODIPY) makes them suitable as potential probes for analytical applications requiring a longer excited state lifetime. [ABSTRACT FROM AUTHOR]