Faculté des sciences

Ruthenium(II) complexes with ferrocene-modified arene ligands: synthesis and electrochemistry

Therrien, Bruno ; Vieille-Petit, Ludovic ; Jeanneret-Gris, Julie ; Štěpnička, Petr ; Süss-Fink, Georg

In: Journal of Organometallic Chemistry, 2004, vol. 689, no. 15, p. 2456-2463

A series of arene–ruthenium complexes of the general formula [RuCl2{η6-C6H5 (CH2)2R}L] with R=OH, CH2OH, OC(O)Fc, CH2OC(O)Fc (Fc=ferrocenyl) and L=PPh3, (diphenylphosphino)ferrocene, or bridging 1,1′-bis(diphenylphosphino)ferrocene, have been synthesized. Two synthetic pathways have been used... More

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    Summary
    A series of arene–ruthenium complexes of the general formula [RuCl26-C6H5 (CH2)2R}L] with R=OH, CH2OH, OC(O)Fc, CH2OC(O)Fc (Fc=ferrocenyl) and L=PPh3, (diphenylphosphino)ferrocene, or bridging 1,1′-bis(diphenylphosphino)ferrocene, have been synthesized. Two synthetic pathways have been used for these ferrocene-modified arene–ruthenium complexes: (a) esterification of ferrocene carboxylic acid with 2-(cyclohexa-1,4-dienyl)ethanol, followed by condensation with RuCl3nH2O to afford [RuCl26-C6H5 (CH2)2OC(O)Fc}]2, and (b) esterification between ferrocene carboxylic acid and [RuCl26-C6H5 (CH2)3OH}L] to give [RuCl26-C6H5 (CH2)3OC(O)Fc}L]. All new compounds have been characterized by NMR and IR spectroscopy as well as by mass spectrometry. The single-crystal X-ray structure analysis of [RuCl26-C6H5 (CH2)3OH}(PPh3)] shows that the presence of a CH2CH2CH2OH side-arm allows [RuCl26-C6H5 (CH2)3OH}(PPh3)] to form an intramolecular hydrogen bond with a chlorine atom. The electrochemical behavior of selected representative compounds has been studied. Complexes with ferrocenylated side arms display the expected cyclic voltammograms, two independent reversible one-electron waves of the Ru(II)/Ru(III) and Fe(II)/Fe(III) redox couples. Introduction of a ferrocenylphosphine onto the ruthenium is reflected by an additonal reversible, one-electron wave due to ferrocene/ferrocenium system which is, however, coupled with the Ru(II)/Ru(III) redox system.