Synthesis, structure, and reactivity of homoleptic cerium(IV) and cerium(III) alkoxides

Ayusman Sen, Hilmar A. Steelier, Arnold L. Rheingold

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Abstract

The reaction of Ce(OCtBu3)3(1) with the following oxidants has been studied: benzoyl peroxide, BzP; di-tert-butyl peroxide, DTBP; tert-butyl peroxybenzoate, BPB; benzoquinone, Bq; 2, 6-di-tert-butylbenzoquinone, DBBq. Ce(OCtBu3)3(OC(O)Ph) (2) was formed in the reaction of 1 with BzP. 1 and DTBP reacted in 1:1 ratio to generate the unstable Ce(IV) species Ce(OCtBu3)2(OtBu)2(3). On the other hand, a 1:0.5 ratio of reactants resulted in the formation of the Ce(III) compound [Ce(OCtBu3)2(OtBu)]2(4). The X-ray crystal structure of 4 (P21/c; a = 11.783 (2) Å, b = 23.606 (6) Å, c = 11.544 (2) Å, β = 95.19 (2)°; 3240 independent reflections with Fo≥ 6γ(Fo); R(F) = 3.79%, Rw(F) = 4.08%; GOF = 1.126) indicated it to be dimeric with a pseudotetrahedral geometry around each cerium atom. The interconversions between 1, 3, and 4 were examined. The reaction of 1 with BPB caused the formation of equal amounts of 2 and 3. 1 was found to react with Bq to form (tBu3CO)3CeOC6H4OCe(OCtBu3)3(5). 5 was structurally characterized (Pi; a = 12.629 (4) Å, b = 12.736 (5) Å, c = 18.148 (8) Å, α = 83.60 (3)°, ς = 76.83 (3)°, γ = 61.57 (3)°; 6403 independent reflections with Fo≥ 5γ(Fo); R(F) = 7.70%, RwF) = 7.97%; GOF = 1.466). The two cerium atoms in the molecule are bridged by a hydroquinonediolate moiety. As expected, the Ce(IV)-0 distances were shorter than the Ce(III)-O bond lengths. Finally, the reaction of 1 with DBBq resulted in the formation of the radical (tBu3CO)3CeOC6H2tBu2O-(6).

Original languageEnglish (US)
Pages (from-to)473-479
Number of pages7
JournalInorganic chemistry
Volume31
Issue number3
DOIs
StatePublished - Feb 1 1992

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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