The Effect of trans Ligands in the NO-Linkage Reverse Isomerization for Ruthenium–Nitrosyl–Tetraammine Complexes: A DFT Study

The rearrangement of the NO ligand in ruthenium–nitrosyl–tetraammine complexes trans-[Ru(NO)(NH₃)₄X]²⁺ (X = F^–, Cl^–, OH^–, SH^–) has been studied for metastable oxygen-coordinated NO complexes by means of DFT. On the basis of obtained data, this rearrangement is concluded to be caused by ligand-to-metal charge transfer of the p(X)→π*(Ru–ON) type. The excitation energy for electron transfer from p-orbital of ligand to LUMO correlates perfectly with the activation energy of isomerization. Found correlations are explained in terms of electronegativity of the trans ligand X.