Oligonuclear ferrocenolato and 1,1 '-ferrocenediolato derivatives of phosphorus: synthesis, structure and electrochemical behaviour

Starting from 1,1′-ferrocenediol, fc(OH)2, several 1,3-dioxa-2-phospha-[3]ferrocenophanes such as [fcO2]P(O)R (R = Cl (1), Ph (2), Fc (3), OFc (4)) and fc(OP[O2fc])2 (5) were synthesized, and both tri(ferrocenyl)phosphite and tri(ferrocenyl)phosphate, P(OFc)3 (6) and P(O)(OFc)3 (7), were obtained starting from ferrocenol, Fc-OH. The new complexes 1–7 were characterized by a consistent set of 1H, 13C and 31P NMR spectroscopic data, and the molecular geometry of 7 was determined by an X-ray crystal structure determination. Electrochemical studies indicate that 3 and 4 are oxidized in two consecutive steps; the formation of the monocations, [3]+ and [4]+, is reversible, and the dication [4]2+ is quite stable. The trimetallic compounds 5–7 undergo two nearly overlapping anodic processes to give the corresponding trications.