Peroxo-Zr/Hf-containing undecatungstosilicates and -germanates.
A family of dimeric, peroxo-containing heteropolytungstates, [M(2)(O(2))(2)(XW(11)O(39))(2)](12-) [M = Zr(4+), X = Si (1), Ge (2); M = Hf(4+), X = Si (3)], have been synthesized by reacting ZrCl(4)/HfCl(4) with the respective monolacunary Keggin precursor [XW(11)O(39)](8-) (X = Si, Ge) in an aqueous acidic medium (pH 4.8). The isostructural polyanions 1-3 are composed of two (XW(11)O(39)) Keggin units encapsulating a central diperoxo-dimetal fragment {M(2)(O(2))(2)}(4+) (M = Zr(4+), Hf(4+)). Cyclic voltammetry and exhaustive electrolysis studies indicate fast reductive release of the peroxo ligands upon reduction of 1-3. Stoichiometric oxo-transfer studies from 1-3 to the substrate l-methionine were performed, and the reactions were monitored by (1)H NMR.
Mal
Sib Sankar
SS
School of Engineering and Science, Jacobs University, P.O. Box 750 561, 28725 Bremen, Germany.
Nsouli
Nadeen H
NH
Carraro
Mauro
M
Sartorel
Andrea
A
Scorrano
Gianfranco
G
Oelrich
Holger
H
Walder
Lorenz
L
Bonchio
Marcella
M
Kortz
Ulrich
U