Novel Titanium-Cobalt Complexes Formed by Reductive Cleavage of a Co-Co Bond in Co2(CO)8 by Titanocene tert-Butoxides: Synthesis, Characterization, and Mechanistic Aspects for Metal-Metal Bond Recombination

Shota Niibayashi, Kaoru Mitsui, Kouki Matsubara, Hideo Nagashima

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13 Citations (Scopus)

Abstract

Reactions of titanium(III) complexes (η5-C5R 5)2TiOtBu (R = H (1), Me (4)) with Co 2(CO)8 are found to be efficient methods to synthesize Ti-Co heterobimetallic complexes. A Ti-Co3 complex, (η 5-C5H5)2Ti(O tBu)(μ4-OC)Co(CO)9 (3), was formed from 1 and Co2(CO)8, whereas a Ti-Co bimetallic complex, (η5-C5Me5)2Ti(O tBu)(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-C 5H5 analogue of 5, [η5-C5H 5)2Ti(OtBu)(μ-OC)Co(CO)3] (6), was formed at the initial stage of the reaction of 1 with Co 2(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 hetero-bimetallic complex, reaction of 6 with THF gave the Ti-Co complex [(η5-C5H5) 2Ti(OtBu)(n-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.

Original languageEnglish
Pages (from-to)4885-4892
Number of pages8
JournalOrganometallics
Volume22
Issue number24
DOIs
Publication statusPublished - Nov 24 2003

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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