Reaction of [RuNO(NO2)4OH]2– with Sulfamic Acid as a Pathway to Mixed Nitro Pyridine Ruthenium Nitrosyl Complexes

Abstract

The transformations of [RuNO(NO2)4OH]2– during sequential treatment with sulfamic acid and pyridine have been investigated by 15N NMR spectroscopy. Depending on the initial molar ratio of Ru/NH2SO3H, the first stage of the reaction at room temperature in an aqueous solution proceeded with stoichiometric removal of one or two NO2 ligands and may be accompanied by ligand redistribution and partial isomerization NO2/ONO. Further treatment with pyridine resulted in the replacement of labile ligands (H2O, SO4) and the formation of mixed nitro pyridine complexes of ruthenium nitrosyl. Mixed nitrito‐N‐nitrito‐O complexes PyH[RuNO(NO2)2(ONO)Py(OH)] and OC‐6‐34‐[RuNO(NO2)(ONO)Py2OH] as well as the dimeric ruthenium complex with µ‐bridging oxo groups NH4[Ru(NO)Py3(µ‐O)]2(PF6)3 were separated as solids and structurally characterized. The photochemical isomerization (445 nm, 9 K) of Ru–NO with the formation of metastable isonitrosyl complexes was found for all the prepared compounds; the population of the metastable state did not exceed 20 %.