Synthesis and crystal structures of cerium(IV) complexes with 8-quinolinolate and amine bis(phenolate) ligands

Two cerium(IV) complexes of Ce(OQ)4 (1) (HOQ = 8-hydroxyquinoline) and Ce(L)2·DME (2·DME) (LH2 = Me2NCH2CH2CH2N{CH2-(3,5-tBu2-C6H2-2-OH)}2) have been synthesized and characterized by elemental analysis, infrared spectra and X-ray crystallography. Complex 1 is a new type of homoleptic 8-quinolinolate lanthanide complex and its overall geometry is like a four-wing-waterwheel. Complex 2 has two tridentate (ONO) amine bis(phenolate) ligands with their terminal N atoms in side-arms without participating in coordination. Both of 1 and 2 can catalyze the oxidation of benzyl alcohol. The conversion of benzyl alcohol by 2 is higher than that by 1 under comparable conditions.

Complexes of Ce(OQ)4 (HOQ = 8-hydroxyquinoline) and Ce(L)2·DME (LH2 = Me2NCH2CH2CH2N{CH2-(3,5-tBu2-C6H2-2-OH)}2) were synthesized, and their catalytic activity for the oxidation of benzyl alcohol was tested.Figure optionsDownload as PowerPoint slideHighlights
► Two tetravalent cerium complexes were synthesized and structurally characterized.
► The structure of homoleptic 8-quinolinolate Ce(IV) complex is different from that of Ho3(OQ)9.
► The amine bis(phenolate) ligands in Ce(IV) complex display in tridentate (ONO) fashion.
► Both the complexes can catalyze the oxidation of benzyl alcohol.