Electrochemistry of Ru-Fe heterobimetallic complexes and the SAM on Au surface

Heterobimetallic Ru-Fe complex trans-RuCl(dppm)(2)(CdropCFc) (1) (Fc = C5H4FeC5H5, dppm = (C6H5)(2)PCH2P (C6H5)(2)) was functionalized to give Ru (dppm)(2) (C drop CFc) (C drop CPhOCH3) (2), [Ru(dppm)(2)(CdropCFc)(NdropCCH(2)CH(2)NH(2))][PF6] (3) and [Ru(dppm)(2)(CdropCFc)(NdropCCH(2)CH(2)NHcircleC(O)(CH2)(10)SH)][PF6] (4) for surface binding. Cyclic voltametric techniques were performed on these complexes to study the extent of perturbation of the surface binding "tail" on the overall electrochemical peroperties. It is found that the substituent on the Ru center adjusts the electron density on the Ru atom and affects the redox properties of the Ru center. However, this substituent effect is not transferred through the acetylene bond to the ferrocenyl moiety. Complex 4 forms a stable and order SAM on the Au surface and CV was used to study the film growth and surface coverage.