New diruthenium complexes, of which two organoruthenium species, (η5-C5Me5)Ru and (η5-C 5H5)Ru, are linked by a bridging amidinate ligand, were synthesized and characterized. Treatment of (η5-C 5Me5)Ru(η-amidinate) [amidinate: iPrN=C(Me) NiPr] with [(η5-C5H5)Ru-(η- NCMe)3]+PF6- resulted in formation of a cationic diruthenium amidinate, [(η5-C5Me 5)-Ru(μ2-amidinate)Ru(η5-C 5H5)(η-NCMe)]+PF6- (4), which was converted to (η5-C5Me 5)Ru-(μ2-amidinate)Ru(η5-C 5H5)X [X = Cl (5a), Br (5b)] by treatment with the halide anion. The molecular structures and spectroscopic data of 4 and 5a including their solution dynamics are compared with their bis-pentamethylcyclopentadienyl homologues, [(η5-C5Me5)Ru- (μ2-aimdinate)Ru(η5-C5Me 5)(η-NCMe)]+PF6- and (η5-C5Me5)Ru(μ2-amidinate) Ru(η5-C5H5)Cl. Treatment of 5a with TlBF4 produced a diruthenium complex, [(η5-C 5Me5)Ru(μ2-amidinate)-Ru(η5- C5H5)]+BF4- (6), bearing 34 valence electrons, which was isolated and characterized by spectroscopy. The coordinatively unsaturated nature of 6 was evidenced by facile reactions with two-electron-donor ligands, NCMe, PMe3, tBuNC, and CO. The coordinatively unsaturated complex 6 and its precursors, 4 and 5, exhibited catalytic activity toward cyclization of N-tosyl-N-allyltrichloroacetamide, which was compared with the corresponding bis-pentamethylcyclopentadienyl homologues.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry