The butadienediyl-bridged complexes [(η5-C5R 5)Fe(dppe)]2(μ-CH=CHCH=CH) (R = H, Me) and their radical cationic and dicationic forms have been prepared and characterized by cyclic voltammetry, electronic spectroscopy (UV-vis and near-IR), EPR, and X-ray crystallography (R = Me). Comparisons with each other and with the literature complexes [(η5-C5R 5)Fe(dppm)]2(μ-CH=CHCH=CH), [(η5-C 5Me5)Fe(dppe)]2(μ-C≡CC≡C), and [(η5-C5Me5)-Fe(dppe)] 2(μ-C(OMe)=CHCH=C(OMe)) have allowed for systematic evaluation of several structural variations (C5H5 vs C 5Me5, dppm vs dppe, μ-CH=CHCH=CH vs μ-C≡CC≡C, and μ-CH=CHCH=CH vs μ-C(OMe)=CHCH=C(OMe)) and their effects on spectra and electronic intermetal coupling. Some of the structural changes have opposite effects on Hab, the effective coupling parameter, and Kc, the comproportionation constant. The data for the mixed-valence cations are most consistent with electronic delocalization.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry