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Synthesis and Some Reactions of the Heterometallic C[subscript 7] Complex {Cp*(dppe)Ru}CCCCCCC{Co[subscript 3]([mu]-dppm)(CO)[subscript 7]}

Journal Article · · Organometallics
DOI:https://doi.org/10.1021/om7010968· OSTI ID:1006849

The heterometallic carbon-chain complex {l_brace}Cp*(dppe)Ru{r_brace}CCCCCCC{l_brace}Co{sub 3}({mu}-dppm)(CO){sub 7}{r_brace} (1) has been obtained by three routes that involve assembly of the C{sub 7} chain by combination of appropriate C{sub 1} + C{sub 6}, C{sub 2} + C{sub 5}, or C{sub 3} + C{sub 4} precursors. The Cp analogue 2 and Co{sub 3}(CO){sub 9} cluster analogue 3 were obtained via the C{sub 2} + C{sub 5} and C{sub 1} + C{sub 6} routes, respectively. Reaction of 1 with PPh{sub 3} gave 4 via substitution of a Co{sub 3} cluster-bonded CO group. Addition of MeOTf to the second carbon from the Ru center in 1 afforded the vinylidene [{l_brace}Cp*(dppe)Ru{r_brace}CCMeCCCCC{l_brace}Co{sub 3}({mu}-dppm)(CO){sub 7}{r_brace}]OTf (5), while addition of tcne or tcnq across the central CC bond gave {l_brace}Cp*(dppe)Ru{r_brace}CCC[C(CN){sub 2}]C[C(CN){sub 2}]CCC{l_brace}Co{sub 3}({mu}-dppm)(CO){sub 7}{r_brace} (6) and {l_brace}Cp*(dppe)Ru{r_brace}CCC[C{sub 6}H{sub 4}C(CN){sub 2}]C[C(CN){sub 2}]CCC{l_brace}Co{sub 3}({mu}-dppm)(CO){sub 7}{r_brace} (7), respectively. The reaction between 1 and Fe 2(CO){sub 9} was more complex, the major product being {l_brace}Cp*(dppe)Ru{r_brace}CCC{l_brace}Fe{sub 3}(CO){sub 9}{r_brace}CCCC{l_brace}Co{sub 3}({mu}-dppm)(CO){sub 7}{r_brace} (8), accompanied by an Fe{sub 2}(CO){sub 6} derivative (9) of as yet undetermined structure. {l_brace}Cp*(dppe)Ru{r_brace}CCCCCCC{l_brace}Co{sub 2}Ni({mu}-dppm)(CO){sub 4}Cp{r_brace} (10) was obtained from the reaction with NiCp{sub 2}. An unstable adduct containing two Co{sub 2}(CO){sub 6} groups attached to the C{sub 7} chain was formed in reactions between 1 and Co{sub 2}(CO){sub 8}. XRD structural studies of 1, 2, 6-8, and 10 are reported. Electrochemical measurements suggest that there is some interaction between the two end groups, although this cannot presently be quantified. It is concluded that the C{sub 7} chain is long enough for the properties of the individual end caps to be preserved, while steric inhibition from the phenyl groups of the dppe and dppm ligands directs addition to the central CC triple bond of the C{sub 7} chain.

Research Organization:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Organization:
USDOE
OSTI ID:
1006849
Journal Information:
Organometallics, Journal Name: Organometallics Journal Issue: (14) ; 2008 Vol. 27; ISSN ORGND7; ISSN 0276-7333
Country of Publication:
United States
Language:
ENGLISH