Reactivity of the metallocarboxylates Cp(NO)(PPh{sub 3})ReCO{sub 2}{sup {minus}}M{sup +} toward excess carbon dioxide: Degradation to a bimetallic {mu}-[{eta}{sup 1}-C(Re):{eta}{sup 1}-O,O{prime}(Re{prime})] carbon dioxide complex Cp(NO)(PPh{sub 3})ReCO{sub 2}Re(NO)(CO)(PPh{sub 3})({eta}{sup 1}-C{sub 5}H{sub 5})
- Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry
The rhenium {eta}{sup 1}-C carboxylate Cp(PPh{sub 3})(NO)ReCO{sub 2}{sup {minus}} (1Li{sup +} or 1K{sup +}) undergoes an unusual reductive disproportionation sequence in the presence of excess CO{sub 2} that generates a new Re{sub 2}({mu}{sub 2}-{eta}{sup 3}-CO{sub 2}) complex Cp(PPh{sub 3})(NO)ReCO{sub 2}Re(CO)(NO)(PPh{sub 3})({eta}{sup 1}-Cp) (2) plus CO{sub 3}{sup 2{minus}}. The overall stoichiometry entails 3 equiv of CO{sub 2} plus 2 equiv of Cp(PPh{sub 3})(NO)ReLi transforming to ligated CO{sub 2} and CO(i.e., 2) plus CO{sub 3}{sup 2{minus}}. Three procedures were used to generate 2: treating (a) Cp(PPh{sub 3})(NO)ReLi with excess CO{sub 2}, (b) 1K{sup +} with excess CO{sub 2}, and (c) 1K{sup +} with Cp(PPh{sub 3})(NO)Re(CO)BF{sub 4}. The results of this study are consistent with the intermediacy of an undetected metalloanhydride Cp(PPh{sub 3})(NO)ReC(O)OC(O)Re(NO)(PPh{sub 3})Cp (8), which upon a subsequent {eta}{sup 5}{r_arrow}{eta}{sup 1} Cp ring shift on one rhenium center affords 2. This product undergoes different solvolysis reactions in the presence of methanol and triethylsilanol. The former gives 2 equiv of the methyl ester Cp(NO)(PPh{sub 3})ReCO{sub 2}CH{sub 3} (6), whereas the latter replaces the {eta}{sup 1}-Cp group with a silanolate to give the previously characterized Cp(PPh{sub 3})(NO)ReCO{sub 2}-Re(CO)(NO)(PPh{sub 3})(OSiEt{sub 3}) (5a).
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 343704
- Journal Information:
- Organometallics, Vol. 18, Issue 9; Other Information: PBD: 26 Apr 1999
- Country of Publication:
- United States
- Language:
- English
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