Investigation of the Excited-State Electron Transfer and Cage Escape Yields Between Halides and a Fe(III) Photosensitizer.
J Am Chem Soc
; 146(15): 10286-10292, 2024 Apr 17.
Article
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| MEDLINE
| ID: mdl-38569088
ABSTRACT
Excited-state quenching and reduction of [Fe(phtmeimb)2]+, where phtmeimb is phenyl[tris(3-methyl-imidazolin-2-ylidene)]borate, with iodide, bromide, and chloride were studied in dichloromethane, acetonitrile, and acetonitrile/water 11 mixture by means of steady-state and time-resolved spectroscopic techniques. Quenching rate constants were almost diffusion-limited in dichloromethane and acetonitrile and followed the expected periodic trend, i.e., I- > Br- > Cl-. Confirmation of excited-state reductive electron transfer was only unambiguously obtained when iodide was used as a quencher. The cage escape yields, i.e., the separation of the geminate radical pair formed upon bimolecular excited-state electron transfer, were determined. These yields were larger in dichloromethane (0.079) than in acetonitrile (0.017), and no photoproduct could be observed in acetonitrile/water 11. This study further emphasizes that solvents with low dielectric constant are more suited for productive excited-state electron transfer using Fe(III) photosensitizers with 2LMCT excited state.
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01-internacional
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MEDLINE
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En
Revista:
J Am Chem Soc
Año:
2024
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Article
País de afiliación:
Bélgica