Intermetal Coupling in [(η5-C5R5)Fe(dppe)]2(μ-CHCHCHCH) and in Their Dicationic and Monocationic Mixed-Valence Forms
摘要:
The butadienediyl-bridged complexes [(eta(5)-C5R5)Fe(dppe)](2)(mu-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 [(eta(5)C(5)H(5))Fe(dppm)](2)(mu-CH=CHCH=CH), [(eta(5)-C5Me5)Fe(dppe)](2)(mu-C=CC=C), and [(eta(5)-C5Me5)Fe(dppe)](2)(mu-C(OMe)=CHCH=C(OMe)) have allowed for systematic evaluation of several structural variations (C5H5 VS C5Me5, dppm vs dppe, mu-CH=CHCH=CH vs mu-C=CC=C, and mu-CH=CHCH=CH Vs mu-C(OMe)=CHCH=C(OMe)) and their effects on spectra and electronic intermetal coupling. Some of the structural changes have opposite effects on H-ab, the effective coupling parameter, and K-c, the comproportionation constant. The data for the mixed-valence cations are most consistent with electronic delocalization.
Intermetal Coupling in [(η5-C5R5)Fe(dppe)]2(μ-CHCHCHCH) and in Their Dicationic and Monocationic Mixed-Valence Forms
摘要:
The butadienediyl-bridged complexes [(eta(5)-C5R5)Fe(dppe)](2)(mu-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 [(eta(5)C(5)H(5))Fe(dppm)](2)(mu-CH=CHCH=CH), [(eta(5)-C5Me5)Fe(dppe)](2)(mu-C=CC=C), and [(eta(5)-C5Me5)Fe(dppe)](2)(mu-C(OMe)=CHCH=C(OMe)) have allowed for systematic evaluation of several structural variations (C5H5 VS C5Me5, dppm vs dppe, mu-CH=CHCH=CH vs mu-C=CC=C, and mu-CH=CHCH=CH Vs mu-C(OMe)=CHCH=C(OMe)) and their effects on spectra and electronic intermetal coupling. Some of the structural changes have opposite effects on H-ab, the effective coupling parameter, and K-c, the comproportionation constant. The data for the mixed-valence cations are most consistent with electronic delocalization.