A practical procedure for production of amines is offered by the ruthenium-catalyzed reduction of carboxamides with polymethylhydrosiloxane, in which encapsulation of the catalyst species into the formed insoluble siloxane resins contributes to the separation of both metallic and siloxane residues from the product.

Reactions of titanium(III) complexes (η5-C5R5)2TiOtBu (R = H (1), Me (4)) with Co2(CO)8 are found to be efficient methods to synthesize Ti−Co heterobimetallic complexes. A Ti−Co3 complex, (η5-C5H5)2Ti(OtBu)(μ4-OC)Co(CO)9 (3), was formed from 1 and Co2(CO)8, whereas a Ti−Co bimetallic complex, (η5-C5Me5)2Ti(OtBu)(μ-OC)Co(CO)3 (5), was obtained by the reaction of 4 with Co2(CO)8. In both cases, the reaction was complete within 5 min. The products were completely characterized by NMR, IR, and X-ray crystallography. Complex 3 contains a quadruply bridging CO group, the oxygen terminus of which is connected to the Ti moiety, whereas the carbon terminus is bound to three Co atoms in the Co3(CO)9 moiety. In contrast, complex 5 is dinuclear, and its Ti atom is connected to the Co(CO)3 group by an isocarbonyl bridge. A η5-C5H5 analogue of 5, [(η5-C5H5)2Ti(OtBu)(μ-OC)Co(CO)3] (6), was formed at the initial stage of the reaction of 1 with Co2(CO)8 in toluene. This dinuclear complex 6 was isolated from a reaction medium of a 5:1 mixture of 1 and Co2(CO)8, being characterized by spectroscopy. As further evidence for the formation of the Ti−Co heterobimetallic complex, reaction of 6 with THF gave the Ti−Co complex [(η5-C5H5)2Ti(OtBu)(η-THF)]+[Co(CO)4]- (7), which was completely characterized by spectroscopy, crystallography, and elemental analysis. Thermal decomposition of 6 produced a mixture of 3 and 1, whereas treatment of 6 with Co2(CO)8 gave 3; this is good evidence for the intermediacy of 6 in the formation of 3 from 1 with Co2(CO)8.

PMHS). -A new concept for efficient Ru-catalyzed reduction of carboxamides with polymethylhydrosiloxane uses the microcapsulation technique for removal of the catalyst species from the product. The latter is self-encapsulated into the insoluble polymer during the reduction. The ruthenium-containing silicon resin can easily be separated, recovered and reused. -(MOTOYAMA, Y.; MITSUI, K.; ISHIDA, T.; NAGASHIMA*, H.; J. Am. Chem. Soc. 127 (2005) 38, 13150-13151; Inst. Mater. Chem. Eng., Kyushu Univ., Kasuga 816, Japan; Eng.) -Bartels 05-065

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