Nitric oxide as an activation agent for nucleophilic attack in trans-[Ru(NO)(NH3)4{P(OEt)3}](PF6)3

The complex trans-[Ru(NO)(NH3)4{P(OEt)3}](PF6)3 undergoes nucleophilic attack on the phosphorus ester ligand in the solid state yielding trans-[Ru(NO)(NH3)4{P(OH)(OEt)2}](PF6)3. The reaction was monitored and the products analyzed using nuclear magnetic resonance spectroscopy (31P{¹H} CP-MAS NMR and 31P{¹H} NMR), infrared spectroscopy (FTIR), electron paramagnetic resonance spectroscopy (EPR), cyclic voltammetry (CV), electronic spectroscopy (UV-Vis) and elemental analysis. According to experimental data and quantum mechanical calculations (DFT), the reaction proceeds in the solid state by the nucleophilic attack on the phosphorus ligand, promoted by the strong polarization along the P III-RuII-NO+ axis induced by the nitrosyl ligand, and takes place following the Michaelis-Arbusov type mechanism for phosphorus ester hydrolysis. In solution, the nucleophilic attack occurs simultaneously at the nitrosyl and triethylphosphite ligands, yielding trans-[Ru(H2O)(NH3)4{P(OEt)3}]2+ and trans-[Ru(NO)(H2O)(NH3)4]3+ in comparable amounts.