Outer‐Sphere 2 e⁻/2 H⁺ Transfer Reactions of Ruthenium(II)‐Amine and Ruthenium(IV)‐Amido Complexes

Abstract

Adiverse set of 2e À /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,e n* = H 2 NCMe 2 CMe 2 NH 2 ,e n*-H = H 2 NCMe 2 CMe 2 NH À ), forming or cleaving different OÀH, NÀH, SÀH, and CÀHb onds.T he reactions involve quinones, hydrazines,t hiols,a nd 1,3-cyclohexadiene.T hese protoncoupled electron transfer reactions occur without substrate binding to the ruthenium center,b ut instead with precursor complex formation by hydrogen bonding.The free energies of the reactions vary over more than 90 kcal mol À1 ,b ut the rates are more dependent on the type of XÀHbond involved than the associated DG8 8.There is akinetic 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,p erhaps hinting at the potential for concerted 2e À /2 H + transfers.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.