Iron versus Ruthenium:  Dramatic Changes in Electronic Structure Result from Replacement of One Fe by Ru in [{Cp*(dppe)Fe}-CC-CC-{Fe(dppe)Cp*}]n+ (n = 0, 1, 2)

M.I. Bruce, K. Costuas, T. Davin, B.G. Ellis, J-F. Halet, C. Lapinte, P.J. Low, M.E. Smith, Brian Skelton, L. Toupet, Allan White

Research output: Contribution to journalArticle

114 Citations (Scopus)

Abstract

The reactions of FeCl(dppe)Cp* and Ru(C equivalent to CC equivalent to CH)L2Cp' with Na[BPh4] and 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu; 2 equiv) in a mixed thf/NEt3 solvent afford {Cp*(dppe)-Fe}(C equivalent to CC equivalent to C){Ru(PP)Cp'} (PP = dppe, Cp' = Cp*, 7; PP = (PPh3)(2), Cp' = Cp, 8). Cyclic voltammetry shows that these mixed Fe/Ru complexes undergo sequential loss of up to three electrons, with the mono- and dioxidized species being isolated following chemical oxidation. Computational (DFT) and spectroscopic (IR, NMR, ESR, Mossbauer) studies are consistent with a polarized ground-state structure with oxidation leading to the gradual evolution of cumulenic character in the FeC4Ru moiety and a greater degree of orbital mixing between the Fe, C, and Ru centers than found in the related heterometallic complex [{Cp*(dppe)-Fe}(C equivalent to CC equivalent to C){Re(NO)(PPh3)Cp*}](n+) ([6](n+)). In contrast to the two-electron oxidation products derived from the diiron complex {Cp*(dppe)Fe}(C equivalent to CC equivalent to C){Fe(dppe)Cp*} (1) and iron/rhenium complex 6, the dications [7](2+) and [8]2+ feature a dominant contribution from a singlet ground state. Thus, while 6 behaves in a manner closely related to 1, 7 and 8 are more closely related to {Cp(Ph3P)(2)Ru}(C equivalent to CC equivalent to C){Ru(PPh3)(2)Cp} (2) and {Cp*(dppe)Ru}-(C equivalent to CC equivalent to C){Ru(dppe)Cp*} (3), clearly demonstrating the pronounced role that choice of metal as well as formal electron count can play in tuning the electronic and magnetic properties of this fascinating class of compound.
Original languageEnglish
Pages (from-to)3864-3881
JournalOrganometallics
Volume24
Issue number16
DOIs
Publication statusPublished - 2005

Fingerprint

Dive into the research topics of 'Iron versus Ruthenium:  Dramatic Changes in Electronic Structure Result from Replacement of One Fe by Ru in [{Cp*(dppe)Fe}-CC-CC-{Fe(dppe)Cp*}]n+ (n = 0, 1, 2)'. Together they form a unique fingerprint.

Cite this