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Süss-Fink, Georg

Nom
Süss-Fink, Georg
Affiliation principale
Fonction
Professeur ordinaire
Email
georg.suess-fink@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/385

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  • Publication
    Accès libre
    Water-soluble arene ruthenium complexes containing pyridinethiolato ligands: Synthesis, molecular structure, redox properties and anticancer activity of the cations [(η6-arene)Ru(p-SC5H4NH)3]2+
    (2008)
    Gras, Michaël
    ;
    Therrien, Bruno 
    ;
    Süss-Fink, Georg 
    ;
    Štěpnička, Petr
    ;
    Renfrew, Anna K.
    ;
    Dyson, Paul J.
    The cationic complexes [(η6-arene)Ru(SC5H4NH)3]2+, arene being C6H6 (1), MeC6H5 (2), p-iPrC6H4Me (3) or C6Me6 (4), have been synthesised from the reaction of 4-pyridinethiol with the corresponding precursor (η6-arene)2Ru2 (μ2-Cl)2Cl2 and isolated as the chloride salts. The single-crystal X-ray structure of [4](PF6)2 reveals three 4-pyridinethiol moieties coordinated to the ruthenium centre through the sulphur atom, with the hydrogen atom transferred from the sulphur to the nitrogen atom. The electrochemical study of 1–4 shows a clear correlation between the Ru(II)/Ru(III) redox potentials and the number of alkyl substituents at the arene ligand (E°′ (RuII/III): 1 > 2 > 3 > 4), whereas the cytotoxicity towards A2780 ovarian cancer cells follows the series 4 > 1 > 3 > 2, the hexamethylbenzene derivative 4 being the most cytotoxic one. The corresponding reaction of the ortho-isomer, 2-pyridinethiol, with (η6-C6Me6)2Ru2 (μ2-Cl)2Cl2 does not lead to the expected 2-pyridinethiolato analogue, but yields the neutral complex (η6-C6Me6)Ru(η2-SC5H4N)(η1-SC5H4N) (5). The analogous complex (η6-C6Me6)Ru(η2-SC9H6N)-(η1-SC9H6N) (6) is obtained from the similar reaction with 2-quinolinethiol.
  • Publication
    Accès libre
    Mono and dinuclear rhodium, iridium and ruthenium complexes containing chelating 2,2′-bipyrimidine ligands: Synthesis, molecular structure, electrochemistry and catalytic properties
    (2007)
    Govindaswamy, Padavattan
    ;
    Canivet, Jérôme
    ;
    Therrien, Bruno 
    ;
    Süss-Fink, Georg 
    ;
    Štěpnička, Petr
    ;
    Ludvík, Jiří
    The mononuclear cations [(η5-C5Me5)RhCl(bpym)]+ (1), [(η5-C5Me5)IrCl(bpym)]+ (2), [(η6-p-PriC6H4Me)RuCl(bpym)]+ (3) and [(η6-C6Me6)RuCl(bpym)]+ (4) as well as the dinuclear dications [{(η5-C5Me5)RhCl}2 (bpym)]2+ (5), [{(η5-C5Me5)IrCl}2 (bpym)]2+ (6), [{(η6-p-PriC6H4Me)RuCl}2 (bpym)]2+ (7) and [{(η6-C6Me6)RuCl}2 (bpym)]2+ (8) have been synthesised from 2,2′-bipyrimidine (bpym) and the corresponding chloro complexes [(η5-C5Me5)RhCl2]2, [(η5-C5Me5)IrCl2]2, [(η6-PriC6H4Me)RuCl2]2 and [(η6-C6Me6)RuCl2]2, respectively. The X-ray crystal structure analyses of [3][PF6], [5][PF6]2, [6][CF3SO3]2 and [7][PF6]2 reveal a typical piano-stool geometry around the metal centres; in the dinuclear complexes the chloro ligands attached to the two metal centres are found to be, with respect to each other, cis oriented for 5 and 6 but trans for 7. The electrochemical behaviour of 1–8 has been studied by voltammetric methods. In addition, the catalytic potential of 1–8 for transfer hydrogenation reactions in aqueous solution has been evaluated: All complexes catalyse the reaction of acetophenone with formic acid to give phenylethanol and carbon dioxide. For both the mononuclear and dinuclear series the best results were obtained (50 °C, pH 4) with rhodium complexes, giving turnover frequencies of 10.5 h−1 for 1 and 19 h−1 for 5.
  • Publication
    Accès libre
    Dinuclear hexamethylbenzene ruthenium cations containing η1:η2-2-(ferrocenyl)ethen-1-yl ligands: Synthesis, structure, electrochemistry
    (2006)
    Tschan, Mathieu J.-L.
    ;
    Therrien, Bruno 
    ;
    Ludvík, Jiří
    ;
    Štěpnička, Petr
    ;
    Süss-Fink, Georg 
    The cationic ferrocenyl-containing complexes [(η6-C6Me6)2Ru2 (μ-η1:η2-CH–CHFc)2 (μ-H)]+ (3) and [(η6-C6Me6)2Ru2 (μ-PPh2)(μ-η1:η2-CH–CHFc)(μ-H)]+ (4) have been synthesised in ethanol from ethynylferrocene and the dinuclear precursors [(η6-C6Me6)2Ru2 (μ-H)3]+ (1) and [(η6-C6Me6)2Ru2(μ-PPh2)(μ-H)2]+ (2) respectively, and isolated as tetrafluoroborate salts. The spectroscopic data of 3 and 4 as well as the single-crystal X-ray diffraction analysis of [4][BF4] show that the alkyne function of ethynylferrocene has been converted to a σ/π-ethenyl ligand by transfer of a bridging hydride from the diruthenium backbone onto the α-carbon of the triple bond in ethynylferrocene. The ferrocenyl-containing diruthenium compounds [3][BF4] and [4][BF4] as well as their parent compounds [1][BF4] and [2][BF4] have been studied by voltammetric techniques: Whereas 1 shows only an irreversible Ru(II)/Ru(III) oxidation, the phosphido-bridged derivative 2 displays two well-separated one-electron redox processes. In the case of 3 and 4, the ferrocenyl substituents give rise to additional reversible ferrocene/ferrocenium waves.
  • Publication
    Accès libre
    Ruthenium(II) complexes with ferrocene-modified arene ligands: synthesis and electrochemistry
    (2004)
    Therrien, Bruno 
    ;
    Vieille-Petit, Ludovic
    ;
    Jeanneret-Gris, Julie
    ;
    Štěpnička, Petr
    ;
    Süss-Fink, Georg 
    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 for these ferrocene-modified arene–ruthenium complexes: (a) esterification of ferrocene carboxylic acid with 2-(cyclohexa-1,4-dienyl)ethanol, followed by condensation with RuCl3 • nH2O to afford [RuCl2{η6-C6H5 (CH2)2OC(O)Fc}]2, and (b) esterification between ferrocene carboxylic acid and [RuCl2{η6-C6H5 (CH2)3OH}L] to give [RuCl2{η6-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 [RuCl2{η6-C6H5 (CH2)3OH}(PPh3)] shows that the presence of a CH2CH2CH2OH side-arm allows [RuCl2{η6-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.