Synthesis, structure and electrochemical properties of 3,4,5-triaryl-1,2-diphosphaferrocenes

Aryl-substituted sodium 1,2-diphosphacyclopentadienides Na(P2C3R3) (R = Ph, 4-Me-C6H4, 4-Cl-C6H4)(1a-c) react with [FeCp(eta(6)-C6H5CH3)][PF6] to give heteroleptic 3,4,5-triaryl-1,2-diphosphaferrocenes [FeCp(eta(5)-P2C3R3)] (2a-c) in 71-78% yield. The structures of 2a-c were confirmed by NMR, UV-Vis spectroscopy and X-ray structure analysis, and supported by DFT calculations. Electrochemical studies of 2a-c in CH3CN demonstrate a pronounced reversible one-electron oxidation, while in the solid state, all 3,4,5-triaryl-1,2-diphosphaferrocenes show fully reversible oxidation and reduction waves, which indicates the stability of the oxidized form. Regardless of the substituent (R = Ph, 4-Me-C6H4, 4-Cl-C6H4), the studied 1,2-diphosphaferrocenes have similar oxidation and reduction potentials.

Automated summary

A series of 3,4,5-triaryl-1,2-diphosphaferrocenes were synthesized and their structures and electrochemical properties were investigated. The results showed that these complexes exhibit good stability of the oxidized form.