A Lewis-acidic anion enhances energy transfer from excited cationic photocatalysts to basic substrates.
- 1Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo Japan [email protected].
- 2Department of Applied Chemistry, Graduate School of Engineering, Kyushu University 744 Motooka, Nishi-ku Fukuoka Japan [email protected].
Abstract
Anions are inherently basic, and the use of counteranions of photocatalysts in substrate activation relies heavily on the Brønsted-basic nature of the anions. Here we present ion-paired dual catalysis using Ru(bpy)₃ ²⁺ with a stable, strongly Lewis-acidic, yet non-nucleophilic anion BBcat. BBcat captures Lewis-basic substrates at the tricoordinated catechol borane (Bcat) centers and keeps them in close proximity to Ru(bpy)₃ ²⁺, affording chemoselective and concentration-independent rate enhancement. In [2+2] photocycloaddition of pyridyl enones, Ru(bpy)₃(BBcat)₂ affords 8.7-times higher yield than Ru(bpy)₃(BArF)₂, and product selectivity is reversed in competitive reactions with a simple chalcone. Quenching experiments and NMR studies confirmed that BBcat facilitates substrate capture by acid-base interactions and the proximity of the ion pair by electrostatic interactions.
Related
- Morphology-Dependent Excited-State Dynamics in Hollow Sphere Poly(Heptazine Imide) Photocatalysts
- Uncovering the high efficiency of aromatic aldehydes as energy transfer photocatalysts
- Tunable Aza-BODIPY Photocatalysts for Near-Infrared Metallaphotoredox Atom Transfer Radical Polymerization
- Concomitant Production and Transfer of Hydrogen for Efficient In Situ Reduction of C–C and C–O Unsaturated Substrates by Pt/TiO2 Photocatalyst in Ethanol
- Vibrational Activation Triggers Ultrafast Excited State Intramolecular Proton Transfer in Single-Benzene Fluorophores
BibTeX
@article{mandai2026lewisacidic,
title = {{A Lewis-acidic anion enhances energy transfer from excited cationic photocatalysts to basic substrates.}},
author = {Ryo Mandai and Yuri Oyama and Takanori Iwasaki and Kyoko Nozaki},
journal = {Chemical science},
year = {2026},
month = oct,
doi = {10.1039/d6sc06879k},
url = {https://europepmc.org/article/MED/42923726},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - A Lewis-acidic anion enhances energy transfer from excited cationic photocatalysts to basic substrates.
AU - Ryo Mandai
AU - Yuri Oyama
AU - Takanori Iwasaki
AU - Kyoko Nozaki
PY - 2026
DA - 2026/10/08
JO - Chemical science
DO - 10.1039/d6sc06879k
UR - https://europepmc.org/article/MED/42923726
AB - Anions are inherently basic, and the use of counteranions of photocatalysts in substrate activation relies heavily on the Brønsted-basic nature of the anions. Here we present ion-paired dual catalysis using Ru(bpy)₃ ²⁺ with a stable, strongly Lewis-acidic, yet non-nucleophilic anion BBcat. BBcat captures Lewis-basic substrates at the tricoordinated catechol borane (Bcat) centers and keeps them in close proximity to Ru(bpy)₃ ²⁺, affording chemoselective and concentration-independent rate enhancement. In [2+2] photocycloaddition of pyridyl enones, Ru(bpy)₃(BBcat)₂ affords 8.7-times higher yield than Ru(bpy)₃(BArF)₂, and product selectivity is reversed in competitive reactions with a simple chalcone. Quenching experiments and NMR studies confirmed that BBcat facilitates substrate capture by acid-base interactions and the proximity of the ion pair by electrostatic interactions.
SN - 2041-6520
SN - 2041-6539
ER -