New complexes and materials for O 2-based oxidations

Abstract

Key experiments in three developing dioxygen activation and oxo transfer projects are described. First, the Pt–oxo complex, K 7Na 9Pt IV(O)(OH 2)(PW 9O 34) 2 (KNa 1) is further addressed and its first reactivity is noted (oxo transfer under Ar at ambient temperature to PPh 3 forming O PPh 3 with nearly quantitative selectivity). Second, an unusually reactive catalyst for aerobic oxygenation of sulfides to sulfoxides (TBANO 3 in the presence of TBA 4Fe(H 2O)PW 11O 39 in acetonitrile solvent) is reported and its stoichiometry is established to be the desired atom-efficient dioxygenase one (RSR + (1/2)O 2 → RS(O)R). Third, a crystalline microporous solid (metal organic framework material) capable of catalyzing air-based oxidations is described. Reaction of the bis(triesterified)hexavanadate unit terminating in two carboxylate functions, [( n-C 4H 9) 4N] 2[V 6O 13{(CH 2O) 3CNHCH 2(4-C 6H 4COOH)} 2] reacts with Co(NO 3) 2·6H 2O and 4,4′-bipyridine to form a ladder-like microporous polymer, characterized by X-ray crystallography, that catalyzes the air-based oxidation of a representative thiol, n-PrSH, cleanly to the corresponding disulfide, PrSSPr. The esterified hexavanadate units are the catalysts, and there is no reaction in the absence of the microporous material.