2025/10/30 by Jonas O. Wenzel, Frank Breher · 1 voice
Chemistry · #Radical Photochemical Reactions #Phosphorus compounds and reactions #Oxidative Organic Chemistry Reactions
paper · doi:10.1002/hlca.202500138
Abstract Bis(pyridylimino) isoindolides (BPIs) are important redox non‐innocent ligands in coordination chemistry and homogeneous catalysis. BPIs can be doubly reduced allowing a change between the mono‐, di‐ and trianionic state. In this article, the first isolation of a monomeric compound with radical dianionic BPI ligand is reported, realized as potassium complex with supporting crown ether ligands. Single‐crystal X‐ray diffraction (SC‐XRD) revealed an η 5 ‐coordination of the five‐membered isoindolide ring, which is so far unprecedented in BPI chemistry. The radical was investigated by electron paramagnetic resonance (EPR) spectroscopy. Structures of the pincer‐type rotamers of BPI in the mono‐, di‐ and trianionic state were calculated by density functional theory (DFT) methods to benchmark the BPI bond lengths theoretically upon varied redox states. Bond lengths within the herein described BPI radical deviate significantly from the free BPI dianion, depicting how careful structure‐redox‐state correlations must be drawn in the coordination chemistry of redox‐active BPIs.