Insertion of Molecular Oxygen in Transition-Metal Hydride Bonds, Oxygen-Bond Activation, and Unimolecular Dissociation of Metal Hydroperoxide Intermediates. Short Communication

✍ Scribed by Maria Schlangen; Helmut Schwarz

• Book ID: 102258721
• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: German
• Weight: 169 KB
• Volume: 91
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200890043

✦ Synopsis

Dedicated to Professor Rudolf Zahradník on the occasion of his 80th birthday Thermal activation of molecular oxygen is observed for the late-transition-metal cationic complexes [M(H)(OH)] þ with M ¼ Fe, Co, and Ni. Most of the reactions proceed via insertion in a metalÀhydride bond followed by the dissociation of the resulting metal hydroperoxide intermediate(s) upon losses of O, OH, and H 2 O. As indicated by labeling studies, the processes for the Ni complex are very specific such that the O-atoms of the neutrals expelled originate almost exclusively from the substrate O 2 . In comparison to the [M(H)(OH)] þ cations, the ionÀmolecule reactions of the metal hydride systems [MH] þ (M ¼ Fe, Co, Ni, Pd, and Pt) with dioxygen are rather inefficient, if they occur at all. However, for the solvated complexes [M(H)(H 2 O)] þ (M ¼ Fe, Co, Ni), the reaction with O 2 involving OÀO bond activation show higher reactivity depending on the transition metal: 60% for the Ni, 16% for the Co, and only 4% for the Fe complex relative to the [Ni(H)(OH)] þ /O 2 couple.