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Mono and dinuclear rhodium, iridium and ruthenium complexes containing chelating 2,2'-bipyrimidine ligands: Synthesis, molecular structure, electrochemistry and catalytic properties
Auteur(s)
Govindaswamy, Padavattan
Canivet, Jerome
Stepnicka, Petr
Ludvik, Jiri
Date de parution
2007
In
J. Organomet. Chem.
Vol.
17
No
692
De la page
3664
A la page
3675
Mots-clés
Résumé
The mononuclear cations [(?5-C5Me5)RhCl(bpym)]+ (1), [(?5-C5Me5)IrCl(bpym)]+ (2), [(?6-p-PriC6H4Me)RuCl(bpym)]+ (3) and [(?6-C6Me6)RuCl(bpym)]+ (4) as well as the dinuclear dications [{(?5-C5Me5)RhCl}2(bpym)]2+ (5), [{(?5-C5Me5)IrCl}2(bpym)]2+ (6), [{(?6-p-PriC6H4Me)RuCl}2(bpym)]2+ (7) and [{(?6-C6Me6)RuCl}2(bpym)]2+ (8) have been synthesized from 2,2'-bipyrimidine (bpym) and the corresponding chloro complexes [(?5-C5Me5)RhCl2]2, [(?5-C5Me5)IrCl2]2, [(?6-PriC6H4Me)RuCl2]2 and [(?6-C6Me6)RuCl2]2, resp. 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 centers; in the dinuclear complexes the chloro ligands attached to the two metal centers are , with respect to each other, cis oriented for 5 and 6 but trans for 7. The electrochem. behavior of 1-8 has been studied by voltammetric methods. In addn., the catalytic potential of 1-8 for transfer hydrogenation reactions in aq. soln. has been evaluated: All complexes catalyze 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°, pH 4) with rhodium complexes, giving turnover frequencies of 10.5 h-1 for 1 and 19 h-1 for 5. [on SciFinder(R)]
Identifiants
Type de publication
journal article
