Süss-Fink, Georg

2007, Govindaswamy, Padavattan, Canivet, Jerome, Therrien, Bruno, Süss-Fink, Georg, Stepnicka, Petr, Ludvik, Jiri

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)]

2005, Canivet, Jerome, Therrien, Bruno, Süss-Fink, Georg

Crystals of the centrosym. dinuclear title complex are triclinic, space group P?1, with a 7.9951(10), b 8.1835(11), c 9.6545(13) Å, ? 69.312(15), ? 69.676(15), ? 86.164(16)°; Z = 1, dc = 2.219; R = 0.023, Rw(F2) = 0.079 for 2014 reflections. The benzene ligands are involved in slipped-parallel ?-? stacking interactions with neighboring mols., thus forming 1-dimensional polymeric chains. [on SciFinder(R)]

2007, Canivet, Jerome, Süss-Fink, Georg, Stepnicka, Petr

The nicotinamide coenzyme NADH, consumed in enantioselective reduction of ketones catalysed by alcohol dehydrogenases, needs to be regenerated in order to maintain enzymatic activity. We therefore studied the catalytic potential of the cationic complexes [(eta(5)-(CMe5)-Me-5)Rh(NnN)Cl](+) (1: N boolean AND N = 1,10-phenanthrohne; 2: NnN = 5 -nitro-1, 10-phenanthroline; 3: NnN = 5-amino-1, 1 0-phenanthroline), [(eta(5)-C5Me5) Ir(N boolean AND N)CI](+) (4: N boolean AND N = 5-nitro-1, 10-phenanthroline) and [(eta(6)-C-6,Me-6)Ru(N boolean AND N)Cl](+) (5: NnN = 5-nitro-1,10-phenanthroline), isolated as the water-soluble chloride salts, for transfer hydrogenation of NAD(+) to give NADH in aqueous solution. The best results were obtained with rhodium complex 1, which gave catalytic turnover frequencies up to 2000 h(-1) in aqueous solution at pH 7 and 60 degrees C with sodium formate as the hydrogen source. When this NADH-regenerating catalytic system is combined with NADH-dependent enzymes, it is possible to chemoenzymatically reduce prochiral ketones such as acetophenone or 4-phenylbutan-2-one with high enantioselectivity. Combination of horse liver alcohol dehydrogenase (HLADH) or alcohol dehydrogenase from Rhodococcus sp. (S-ADH) with 1/formate as the NADH-regenerating system resulted in ee values up to 98 %, depending on the nature of the substrate and the enzyme. In order to explain the different catalytic activities, the electrochemical behaviour of complexes 1-5 has been studied. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

2006, Canivet, Jerome, Therrien, Bruno, Süss-Fink, Georg

The enantiomerically pure iridium title complex, [Ir(C13H19N2O2S)(C10H15)Cl]·CHCl3, has the Ir atom in the S configuration, with a distorted octahedral geometry. [on SciFinder(R)]