Oxidation of alkylbenzenes with cerium complexes containing a tripodal oxygen ligand

Xiao Yi Yi, Guo Cang Wang, Ho Fai Ip, Wai Yeung Wong, Lizhuang Chen, Herman H.Y. Sung, Ian D. Williams, Wa Hung Leung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

11 Citations (Scopus)

Abstract

KGaA, Weinheim. The treatment of [Ce(LOEt)2(NO3)2] (LOEt- = [Co(η5-C5H5){P(O)(OEt)2}3]-) with KMnO4 in water afforded a diamagnetic purple solid 1, which is tentatively formulated as a CeIV permanganate complex, "[Ce(LOEt)2(MnO4)2]". The ZrIV analogue, [Zr(LOEt)2(MnO4)2] (2), has been prepared similarly from [Zr(LOEt)2(NO3)2] and KMnO4. The recrystallization of 1 from CH2Cl2/hexanes at -18 C led to the isolation of dinuclear [(CeLOEt)2(μ-LOEt′)2][MnO4]2 (3), which contains the dianionic tripodal ligand [LOEt′]2- ([(η5-C5H5)Co{P(O)(OEt)2}2{P(O)2(OEt)}]2-). The reactions of 1 with K[ReO4] and [NH4][OsO3N] afforded the heterodimetallic complexes [Ce(LOEt)2(ReO4)2] (4) and [Ce(LOEt)2(NOsO3)2] (5), respectively. The crystal structures of 3 and 5 have been determined. Freshly prepared 1 can oxidize alkylbenzenes such as toluene, ethylbenzene, and cumene at room temperature to give the corresponding ketone and/or alcohol products. Ce-LOEt complexes are efficient promoters of the aerobic oxidation of alkylbenzenes by a radical mechanism. For example, cumene in the presence of [Ce(LOEt)2(H2O)2]Cl (1 mM) in air at 100 C for 10 h afforded a ca. 6:1 mixture of 2-phenyl-2-propanol and acetophenone with a total turnover number of 6810.
Original languageEnglish
Pages (from-to)6097-6103
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Volume2014
Issue number35
DOIs
Publication statusPublished - 1 Jan 2014
Externally publishedYes

Keywords

  • Alkylbenzenes
  • Cerium
  • Heterometallic complexes
  • O ligands
  • Oxidation

ASJC Scopus subject areas

  • Inorganic Chemistry

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