Exploring possible reaction pathways for the o‐atom transfer reactions to unsaturated substrates catalyzed by a [Ni‐NO2] ↔ [Ni‐NO] redox couple using DFT methods

The (nitro)(N‐methyldithiocarbamato)(trimethylphospane)nickel(II), Ni(NO₂)(S₂CNHMe)(PMe₃)] complex catalyses efficiently the O‐atom transfer reactions to CO and acetylene. Energetically feasible sequence of elementary steps involved in the catalytic cycle of the air oxidation of CO and acetylene are proposed promoted by the Ni(NO₂)(S₂CNHMe)(PMe₃)] ↔ Ni(NO₂)(S₂CNHMe)(PMe₃) redox couple using DFT methods both in vacuum and dichloromethane solutions. The catalytic air oxidation of HC≡CH involves formation of a five‐member metallacycle intermediate, via a 3 + 2] cyclo‐addition reaction of HC≡CH to the Ni‐N = O moiety of the Ni(NO₂)(S₂CNHMe)(PMe₃)] complex, followed by a β H‐atom migration toward the C_α carbon atom of the coordinated acetylene and release of the oxidation product (ketene). The geometric and energetic reaction profile for the reversible Ni( ‐NO₂)(S₂CNHMe)(PMe₃)] Ni( ‐ONO)(S₂CNHMe)(PMe₃)] linkage isomerization has also been modeled by DFT calculations. © 2017 Wiley Periodicals, Inc.