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Luminescent 1H-1,3-benzazaphospholes
Sloane Evariste1, Alexandra M Harrison1, Sunandan Sarkar2
1Department of Chemistry, Case Western Reserve University Cleveland Ohio 44106 USA protasiewicz@case.edu.
RSC Advances
|January 6, 2023
Summary
This study synthesizes and characterizes new 2-R-1,3-benzazaphospholes (R-BAPs), finding that thiophene-substituted R-BAPs exhibit significant fluorescence, unlike their methyl-substituted counterparts. These findings offer insights into structure-property relationships for photoluminescent materials.
Area of Science:
- Organic Chemistry
- Materials Science
- Photochemistry
Background:
- 2-R-1,3-benzazaphospholes (R-BAPs) are σ2P heterocycles with P=C bonds.
- Related benzoxaphospholes (R-BOPs) are known photoluminescent materials.
- Photoluminescence in R-BAPs was previously limited to fused carbazole systems.
Purpose of the Study:
- Synthesize and structurally characterize a new R-BAP derivative (3c, R = 2,2'-dithiophene).
- Compare the photoluminescence of novel R-BAPs (3b, 3c) with a known analogue (3a).
- Investigate structure-property relationships influencing excited-state relaxation in R-BAPs.
Main Methods:
- Synthesis of 2-R-1,3-benzazaphosphole derivatives.
- Structural characterization using spectroscopic and crystallographic techniques.
- Photoluminescence quantum yield (φ) measurements and computational studies.
Main Results:
- Significant fluorescence observed for thiophene derivatives 3b (φ = 0.53) and 3c (φ = 0.12).
- Weakly emissive behavior noted for the methyl-substituted analogue 3a (φ = 0.08).
- Computational analysis provided insights into excited-state relaxation pathways.
Conclusions:
- Thiophene substituents enhance photoluminescence in R-BAPs compared to methyl groups.
- Structure-property relationships are critical for tuning the photoluminescent behavior of R-BAPs.
- These findings expand the scope of R-BAPs as potential photoluminescent materials.
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