Complexes of Ferrocenyl‐Containing Polysiloxanes and Iron Triad Metals as Multiredox Active Materials

ABSTRACT Novel heterobimetallic polymer‐metal complexes (PMCs) based on ferrocenyl‐containing polysiloxanes with pyridine‐2,6‐dicarboxamide moieties coordinated with Co II , Ni II , and Fe II metallocenters ( M‐PyPMFS s), as well as ferrocenyl‐containing polysiloxanes with 2,2′‐bipyridine‐4,4′‐dicarboxamide fragments coordinated with Co II and Ni II metallocenters ( M‐BipyP(MFS‐ co ‐DMS) s) were obtained by polymerization, polycondensation, and complexation reactions. The structure of the ferrocenyl‐containing polymer ligands and their PMCs was confirmed by NMR, FTIR, UV–Vis, and EDX spectroscopies. The electrochemical behavior of the PMCs was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Both M‐PyPMFS s and M‐BipyP(MFS‐ co ‐DMS) s exhibit multiredox activity due to the presence of two redox active metallocenters (ferrocenyl group and Ni II , Co II , or Fe II coordination cross‐links). A comprehensive analysis of the redox properties is conducted to establish the influence of both metallocenter and polymer ligand in the M‐PyPMFS s— M‐BipyP(MFS‐ co ‐DMS) s series. Thus, M‐PyPMFS s demonstrate enhanced multiredox performance over M‐BipyP(MFS‐ co ‐DMS) s, as evidenced by their two intensive well‐resolved redox processes in CVs at E 1/2 ≈ 0.1 V (Fc/Fc + couple) and at E 1/2 ≈ 0.8–1.1 V (Co II /Co III and Ni II /Ni III couples). However, M‐BipyP(MFS‐ co ‐DMS) s exhibit up to three redox transitions (Fc/Fc + , M II /M III , and Bipy •− /Bipy mixed with M I /M II ). These polymer‐metal complexes enable new applications as multiredox silicone materials in polymer engineering, especially for (opto)electronic, adaptive electrochromic, and stimuli‐responsive devices.