title: Rhenium oxo compounds containing eta2-pyrazolate ligands.
abstract: Reaction of potassium salts of sterically demanding pyrazolates (pz = bis-3,5-tert-butylpyrazolate, pz= bis-3,5-tert-butyl-4-methylpyrazolate) with Re2O7 affords soluble eta2-pyrazolate complexes of the type [(eta2-pz)ReO3(THF)n](1: pz, n= 1 and 2: pz, n= 0). They were characterized by spectroscopic methods and by X-ray crystallography confirming the eta2-coordinate ligands. Complex 1 employing the ligand with a proton in the 4-position retains one molecule of THF, whereas the additional methyl group in 2 leads to the base-free compound 2. Compound 1 reacts with pyridine and 3,5-dimethylpyridine to form Lewis base adducts of the type [(eta2-pz)ReO3(L)](3: L = py; 4: L = 3,5-Me2py). The pronounced sensitivity towards water of these complexes is demonstrated by the reaction of 1 with one equivalent of water forming the corresponding pyrazolium perrhenate [ReO4][pzH2](5). Its solid state structure shows a hydrogen bonded dimeric assembly. Catalytic activity of 1 is established in oxygen atom transfer-reactions (OAT) from dimethylsulfoxide to triphenylphosphine, and in epoxidations of cyclooctene employing bis(trimethylsilyl) peroxide (BTSP).
authors.affiliation: Institut fur Anorganische Chemie, Georg-August-Universitat Gottingen, Tammannstrasse 4, D-37077 Gottingen, Germany. nmoesch@gwdg.de
authors.forename: Nadia C
authors.initials: NC
authors.lastname: Mosch-Zanetti
authors.forename: Anna
authors.initials: A
authors.lastname: Sachse
authors.forename: Roland
authors.initials: R
authors.lastname: Pfoh
authors.forename: Denis
authors.initials: D
authors.lastname: Vidovic
authors.forename: Jorg
authors.initials: J
authors.lastname: Magull