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Outer‐Sphere 2 e − /2 H + Transfer Reactions of Ruthenium(II)‐Amine and Ruthenium(IV)‐Amido Complexes
Author(s) -
Cattaneo Mauricio,
Ryken Scott A.,
Mayer James M.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201612642
Subject(s) - ruthenium , chemistry , amine gas treating , hydrogen bond , bipyridine , stereochemistry , medicinal chemistry , crystallography , molecule , photochemistry , catalysis , crystal structure , organic chemistry
A diverse set of 2 e − /2 H + reactions are described that interconvert [Ru II (bpy)(en*) 2 ] 2+ and [Ru IV (bpy)(en‐H*) 2 ] 2+ (bpy=2,2′‐bipyridine, en*=H 2 NCMe 2 CMe 2 NH 2 , en*‐H=H 2 NCMe 2 CMe 2 NH − ), forming or cleaving different O−H, N−H, S−H, and C−H bonds. The reactions involve quinones, hydrazines, thiols, and 1,3‐cyclohexadiene. These proton‐coupled electron transfer reactions occur without substrate binding to the ruthenium center, but instead with precursor complex formation by hydrogen bonding. The free energies of the reactions vary over more than 90 kcal mol −1 , but the rates are more dependent on the type of X−H bond involved than the associated Δ G °. There is a kinetic preference for substrates that have the transferring hydrogen atoms in close proximity, such as ortho ‐tetrachlorobenzoquinone over its para ‐isomer and 1,3‐cyclohexadiene over its 1,4‐isomer, perhaps hinting at the potential for concerted 2 e − /2 H + transfers.