Abstract: It is shown that diammine–nitrate complexes of nitrosylruthenium [RuNO(NH3)2(NO3)3] undergo rapid aquation in acidic aqueous solutions yielding [RuNO(NH3)2(H2O)3]3+ cations. The acid dissociation processes of the mer/fac-[RuNO(NH3)2(H2O)3]3+ were studied by potentiometric titration and IR spectroscopy. The dissociation constants (pKa1,2,3 = 1.29, 3.65, 7.12 and 2.29, 5.06, 7.1 for the mer- and facisomers, respectively) and the thermodynamic parameters (ΔH°, ΔS°) of the dissociation processes were determined. The greatest difference in the dissociation process is observed for the second step (pKa2) due to differences in the coordination of water molecules. IR spectroscopy confirmed that the first dissociation step in both isomers corresponds to the deprotonation of the aqua ligand coordinated in the trans position to the nitrosyl group.

Cite: Galkin D.L. , Kostin G.A. , Vorobyev V.A.
Determination of the Acid–Base Dissociation Constants of mer- and fac-Triaquadiamminenitrosylruthenium Complexes
Russian Journal of Inorganic Chemistry. 2026. V.71. N6. P.765-775. DOI: 10.1134/S0036023626600991 WOS

Dates:

Submitted:	Feb 3, 2026
Published print:	Jun 1, 2026

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≡ Web of science:

WOS:001835321500011

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