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Tautomerization of Methyldiazene to Formaldehyde-Hydrazone in Ruthenium and Osmium Complexes

2005; American Chemical Society; Volume: 44; Issue: 24 Linguagem: Inglês

10.1021/ic050817z

1520-510X

Gabriele Albertin, Stefano Antoniutti, Alessia Bacchi, Fabiola De Marchi, Giancarlo Pelizzi,

Lanthanide and Transition Metal Complexes

Mixed-ligand hydrazine complexes [M(CO)(RNHNH2)P4](BPh4)2 (1, 2) [M = Ru, Os; R = H, CH3, C6H5; P = P(OEt)3] with carbonyl and triethyl phosphite were prepared by allowing hydride [MH(CO)P4]BPh4 species to react first with HBF4·Et2O and then with hydrazines. Depending on the nature of the hydrazine ligand, the oxidation of [M(CO)(RNHNH2)P4](BPh4)2 derivatives with Pb(OAc)4 at −30 °C gives acetate [M(κ1-OCOCH3)(CO)P4]BPh4 (3a), phenyldiazene [M(CO)(C6H5NNH)P4](BPh4)2 (3c, 4c), and methyldiazene [M(CO)(CH3NNH)P4](BPh4)2 (3b, 4b) derivatives. Methyldiazene complexes 3b and 4b undergo base-catalyzed tautomerization of the CH3NNH ligand to formaldehyde-hydrazone NH2NCH2, giving the [M(CO)(NH2NCH2)P4](BPh4)2 (5, 6) derivatives. Complexes 5 and 6 were characterized spectroscopically and by the X-ray crystal structure determination of the [Ru(CO)(NH2NCH2){P(OEt)3}4](BPh4)2 (5) derivative. Acetone-hydrazone [M(CO){NH2NC(CH3)2}P4](BPh4)2 (7, 8) complexes were also prepared by allowing hydrazine [M(CO)(NH2NH2)P4](BPh4)2 derivatives to react with acetone.