120608-47-1Relevant articles and documents
Complexes of rhenium carbonyl containing ferrocenyl-derived ligands: Tunable electron density at rhenium by control of the redox state of the ferrocenyl ligand
Miller, Timothy M.,Ahmed, Kazi J.,Wrighton, Mark S.
, p. 2347 - 2355 (2008/10/08)
The new complexes (Fe(C5H4PPh2)2)Re(CO)3Cl, cis-(FcPPh2)Re(CO)4Cl, fac-(FcPPh2)2Re(CO)3Cl, fac-(FcPy)2Re(CO)3Cl, and FcRe(CO)5 (Fc = ferrocenyl; Py = 4-pyridyl) have been synthesized and characterized for the purpose of investigating the tunability of the electron density on Re by changes in the redox state of the ferrocene center(s). The structures of (Fe-(C5H4PPh2)2)Re(CO)3Cl and fac-(FcPPh2)2Re(CO)3Cl were solved by X-ray crystallography. Structural parameters: for (Fe(C5H4PPh2)2)Re(CO)3Cl, a = 11.650 (2) ?, b = 19.534 (5) ?, c = 14.318 (2) ?, β = 93.76 (1)°, V = 3251 (2) ?3, Z = 4, space group P21/c, R1 = 0.032, R2 = 0.033; for fac-(FcPPh2)2Re(CO)3Cl, a = 11.859 (2) ?, b = 20.105 (4) ?, c = 17.060 (3) ?, β = 92.26 (1)°, V = 4064 (2) ?3, Z = 4, space group P21/c, R1 = 0.049, R2 = 0.049. All of the complexes exhibit ferrocene-based, reversible oxidations. The oxidized complexes were prepared in situ, either by electrolysis in a spectroelectro-chemical cell or by chemical oxidation, and characterized by spectroscopic methods (IR and UV/vis) and by reduction back to the neutral complexes. The carbonyl stretching frequencies in all of the complexes shift to higher energy upon oxidation. The magnitudes of the shifts range from 12-33 cm-1 for FcRe(CO)5 to 4-7 cm-1 for (FcPy)2Re(CO)3Cl and are closely related to the number of bonds separating the ferrocene moiety and the Re atom.
