Theoretical studies on the redox stimulated intramolecular isomerization in [Ru(pic)(tpy)(dmso)]+

Redox induced intramolecular Ru–S → Ru–O and Ru–O → Ru–S isomerization of the coordinated sulfoxide group in [Ru(pic)(tpy)(dmso)]+ (pic = 2-picolinate; tpy = 2,2′:6′,2″-terpyridine; dmso = dimethyl sulfoxide) was explored theoretically. Calculated results show that the energy barrier for the Ru–S–Ru–O linkage isomerization is decreased by one-electron oxidation, while is increased by one-electron reduction. Moreover, compared with that in the Ru(II) and Ru(I) sulfoxide complexes, intramolecular Ru–S → Ru–O isomerization is more thermodynamically favored in the Ru(III) complexes. Differently, the energy barrier for the reaction path from Ru–O to Ru–S linkage mode is increased by one-electron oxidation, while is decreased by one-electron reduction. Then, it can be concluded that the Ru–S → Ru–O isomerization is favored by Ru(II) oxidation, while Ru–O → Ru–S isomerization is easier to be induced by Ru(III) or Ru(II) reduction.