The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides.

Title The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides.
Authors J.M. Hoffman; A.G. Oliver; S.N. Brown
Journal J Am Chem Soc
DOI 10.1021/jacs.7b00985
Abstract

The rhenium(V) oxo complex oxo(triphenylphosphine) (bis(3,5-di-tert-butyl-2-phenoxo)amido)rhenium(V), (ONO(Cat))ReO(PPh3), reacts with molecular oxygen to give triphenylphosphine oxide and the dimeric rhenium(VII) complex fac,anti-(ONO(Cat))Re(O)(?-O)2Re(O)(ONO(Cat)). The ONO ligand adopts an unusual fac geometry, presumably to maximize ? donation to rhenium; strong ? donation is substantiated by the intraligand bond distances (metrical oxidation state = -2.24(9)). Addition of the N-heterocyclic carbene ligand IMes to fac,anti-(ONO(Cat))Re(O)(?-O)2Re(O)(ONO(Cat)) cleaves the dimer into monomeric C1-symmetric fac-(ONO(Cat))ReO2(IMes). The monorhenium(VII) complex is deoxygenated by PMe2Ph to give the rhenium(V) compound (ONO(Cat))ReO(IMes), which can be independently prepared by ligand substitution of (ONO(Cat))ReO(PPh3). The degree of stereochemical rigidity exhibited by the dioxo compound, as established by dynamic NMR spectroscopy, excludes the intermediacy of mer-(ONO(Q))Re(V)O2(IMes) in this oxygen atom transfer reaction. Thus, oxygen atom transfer takes place preferentially by direct reduction of the oxorhenium(VII) moiety (classical oxygen atom transfer) rather than through initial internal electron transfer and ligand-centered reduction of an oxorhenium(V)-iminoquinone.

Citation J.M. Hoffman; A.G. Oliver; S.N. Brown.The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides.. J Am Chem Soc. 2017. doi:10.1021/jacs.7b00985

Related Elements

Rhenium

See more Rhenium products. Rhenium (atomic symbol: Re, atomic number: 75) is a Block D, Group 7, Period 6 element with an atomic weight of 186.207. The number of electrons in each of rhenium's shells is 2, 8, 18, 32, 13, 2 and its electron configuration is [Xe] 4f14 5d5 6s2. Rhenium Bohr ModelThe rhenium atom has a radius of 137 pm and a Van der Waals radius of 217 pm. Rhenium was discovered and first isolated by Masataka Ogawa in 1908. In its elemental form, rhenium has a silvery-white appearance. Rhenium is the fourth densest element exceeded only by platinum, iridium, and osmium. Rhenium's high melting point is exceeded only by those of tungsten and carbon.Elemental Rhenium Rhenium is found in small amounts in gadolinite and molybdenite. It is usually extracted from the flue dusts of molybdenum smelters. The name Rhenium originates from the Latin word 'Rhenus' meaning "Rhine" after the place of discovery.

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