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We have rationally designed and synthesized a library of phosphaquinolinone derivatives containing various electron-donating and -withdrawing groups on two positions of the scaffold. Distinct trends are observed between the substituents on R 1 and R 2 with both the photophysical properties of the molecules and their dimerization strengths. With withdrawing groups upon the scaffold, dimerization constants surpass 500 M −1 in H 2 O-saturated CDCl 3 . Computational studies on the dimeric structures corroborate the experimental findings.
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This content will become publicly available on January 1, 2027
Synthesis and photophysical properties of 1,3,5,7-tetraphenyl-aza-BODIPYs substituted at the p-phenyl positions with electron-withdrawing or donating groups
A series of 1,3,5,7-tetraphenyl-aza-BODIPY dyes functionalized with electron-donating or withdrawing groups at the para-positions of the phenyl rings on either the 1,7- or 3,5-positions were synthesized and characterized. The electron-donating group selected was –NH2, while the electron-withdrawing groups spanned a range of strengths, from strong (-NO2) to moderate (-NH3+) and mild (-Ndouble bondCdouble bondS). The structural modifications were strategically implemented to investigate their impact on the dyes photophysical properties. Spectroscopic studies revealed that these dyes exhibit intense absorption and emission in the near-infrared (NIR) region (678–855 nm). The photophysical properties, including molar absorptivity, fluorescence quantum yield, and Stokes shift were found to depend significantly on both the electronic nature (donating/withdrawing) and positioning (1,7- vs. 3,5-) of the substituents. Complementary computational studies provided insights into the electronic structures and excited-state dynamics, corroborating experimental observations. Time-dependent density functional theory (TD-DFT) calculations revealed that the electron density distribution and the frontier orbitals’ energies and shapes were significantly influenced by the electronic effects of the substituent groups. This study underscores the tunability of aza-BODIPY dyes through rational molecular design, enabling precise control over their optical properties for tailored NIR applications.
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- Award ID(s):
- 2320718
- PAR ID:
- 10634094
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Dyes and Pigments
- Volume:
- 244
- Issue:
- C
- ISSN:
- 0143-7208
- Page Range / eLocation ID:
- 113144
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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