Reaction of [RuNO(NO 2 ) 4 OH] 2– with Sulfamic Acid as a Pathway to Mixed Nitro Pyridine Ruthenium Nitrosyl Complexes

The transformations of [RuNO(NO 2 ) 4 OH] 2– during sequential treatment with sulfamic acid and pyridine have been investigated by 15 N NMR spectroscopy. Depending on the initial molar ratio of Ru/NH 2 SO 3 H, the first stage of the reaction at room temperature in an aqueous solution proceeded with stoichiometric removal of one or two NO 2 ligands and may be accompanied by ligand redistribution and partial isomerization NO 2 /ONO. Further treatment with pyridine resulted in the replacement of labile ligands (H 2 O, SO 4 ) and the formation of mixed nitro pyridine complexes of ruthenium nitrosyl. Mixed nitrito‐ N ‐nitrito‐ O complexes PyH[RuNO(NO 2 ) 2 (ONO)Py(OH)] and OC‐6‐34‐[RuNO(NO 2 )(ONO)Py 2 OH] as well as the dimeric ruthenium complex with µ‐bridging oxo groups NH 4 [Ru(NO)Py 3 (µ‐O)] 2 (PF 6 ) 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 %.