title: 6-Peroxo-6-zirconium crown and its hafnium analogue embedded in a triangular polyanion: [M6(O2)6(OH)6(gamma-SiW10O36)3]18- (M = Zr, Hf).
abstract: We have synthesized and structurally characterized the unprecedented peroxo-zirconium(IV) containing [Zr6(O2)6(OH)6(gamma-SiW10O36)3]18- (1). Polyanion 1 comprises a cyclic 6-peroxo-6-zirconium core stabilized by three decatungstosilicate units. We have also prepared the isostructural hafnium(IV) analogue [Hf6(O2)6(OH)6(gamma-SiW10O36)3]18- (2). We investigated the acid/base and redox properties of 1 by UV-vis spectroscopy and electrochemistry studies. Polyanion 1 represents the first structurally characterized Zr-peroxo POM with side-on, bridging peroxo units. The simple, one-pot synthesis of 1 and 2 involving dropwise addition of aqueous hydrogen peroxide could represent a general procedure for incorporating peroxo groups into a large variety of transition metal and lanthanide containing POMs.
authors.affiliation: School of Engineering and Science, Jacobs University, P.O. Box 750561, 28725 Bremen, Germany.
authors.forename: Bassem S
authors.initials: BS
authors.lastname: Bassil
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Mal
authors.forename: Michael H
authors.initials: MH
authors.lastname: Dickman
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kortz
authors.forename: Holger
authors.initials: H
authors.lastname: Oelrich
authors.forename: Lorenz
authors.initials: L
authors.lastname: Walder