Synthesis and Electrochemical Behavior of Ferrocenyl β ‐Ketoamines FcC(O)CH=C(NH(C 6 H 4 ‐4‐R‘))R

FcC(O)CH=C(OH)R ( 1 , R=Me; 2 , R=Fc; Fc=Fe( η 5 ‐C 5 H 4 )( η 5 ‐C 5 H 5 )) reacts with 1‐H 2 N‐4‐R’‐C 6 H 4 ( 3 a , R‘=Me; 3 b , R‘=OMe; 3 c , R‘=C≡N; 3 d , R‘=F) producing β ‐ketoamines FcC(O)CH=C(NH(C 6 H 4 ‐4‐R‘))R ( 4 a – d , R=Me; 5 a – d , R=Fc). Electrochemistry shows that 4 a – d possess one ( 4 a : E°′ =90 mV; 4 b : E°′ =80 mV; 4 c : E°′ =145 mV; 4 d : E°′ =95 mV) and 5a – d two ( 5 a : E°′ 1,2 =90, 305 mV; 5 b : E°′ 1,2 =85, 305 mV; 5 c : E°′ 1,2 =155, 360 mV; 5 d : E°′ 1,2 =105, 325 mV) reversible redox processes. In 5 a – d electrostatic interactions occur among Fc/[Fc] + as oxidation progresses, as evidenced by UV/vis‐NIR spectroscopy. Compounds 4 a , d and 5 b , c display an irreversible N ‐oxidation at 1100–1450 mV, while 4 b owns a reversible event at 910 mV. A linear relationship between the σ Hammett constants and the E°′ 1 values exists.