A procedure for the synthesis of trans-Ru(NO)(Py)2Cl2(OH) (I) from K2[Ru(NO)Cl5] was proposed. Treatment of hydroxo complex I with HCl or H2SO4 at room temperature gave the corresponding salts trans-[Ru(NO)(Py)2Cl2(H2O)]Cl · 2H2O (II) and trans-[Ru(NO)(Py)2Cl2(H2O)]HSO4 (III). All the complexes obtained were characterized by 1H and 13C NMR and IR spectroscopy and elemental analysis; their structures were determined by X-ray diffraction. The structures are stabilized by π-stacking between the pyridine ligands of adjacent complex species.

The state of ruthenium in conjugated phases upon extraction of trans-[Ru(15NO)(15NO2)4(OH)]2− complex with tri-n-octylphosphine oxide (TOPO) in the presence of Zn2+ and subsequent back extraction with H15NO3 and NH3(concd.) solutions was studied by 15N NMR. Binuclear complexes [Ru(NO)(NO2)5−n (μ-NO2) n−1(μ-OH)Zn(TOPO) n ] and [Ru(NO)(NO2)4−n (ONO)(μ-NO2) n−1(μ-OH)Zn(TOPO) n ], where n = 2, 3, are predominant forms in extract. Kinetic restrictions for ruthenium extraction with TOPO solution in hexane and its back extraction with aqueous solutions of nitric acid and ammonia are eliminated in the absence of direct coordination of extractant to ruthenium. fac-Dinitronitrosyl forms [Ru(NO)(H2O)3(NO2)2]+, [Ru(NO)(H2O)2(NO2)2(NO3)]0 (3 and 6 M HNO3) and [Ru(NO)(H2O)(NO2)2(NO3)2]− (6 M HNO3) prevail in nitric acid back extracts. Equilibrium constant at ambient temperature (0.05 ± 0.01) was assessed for the coordination of second nitrate ion to nitrosylruthenium dinitronitrato complex. Complex species [Ru(NO)(NO2)4(OH)]2− and [Ru(NO)(NO2)3(ONO)(OH)]2− prevail in ammonia back extract.

Aqueous and nitric acid solutions of Na2[Ru15NO(15NO2)4OH] in the concentration range \(c_{H^{15} NO_3 }\) = 0–3.3 mol/L have been studied by 15N NMR, dominating complex species have been identified, and the equilibrium constants for the nitrate ion incorporation into the inner coordination sphere of nitrosoruthenium have been estimated. The equilibration time for such equilibria is no more than 2 h at room temperature. In addition to the nitro complexes, isomeric nitritonitronitrosoruthenium compounds have been identified in solutions. In weak acidic solutions at \(c_{HNO_3 }\) < 0.25 mol/L, nitro and nitritonitro complexes containing four and three coordinated nitrite ions predominate. At the HNO3 concentration 0.4–1.7 mol/L, the vast majority of ruthenium presents in solution as fac-dinitronitrosoruthenium complexes containing coordinated water molecules and nitrate ions. In solutions with \(c_{HNO_3 }\) > 1.5 mol/L, the fractions of dinitro- and mononitronitrosoruthenium complexes are comparable. In strong nitric acid solutions (\(c_{H^{15} NO_3 }\) = 10 mol/L) kept for three years in contact with air, nitro complexes are absent, and mononitrato- and dinitratoaquanitrosoruthenium complexes are dominating.

The reaction of trans-[RuNO(NH3)4(OH)]Cl2 with nitric acid has been studied. Reaction products have been identified by IR spectroscopy, NMR, mass spectrometry, powder and single-crystal X-ray diffraction, and chemical analysis. Synthesis methods have been developed for amminenitrosoruthenium complexes containing outer-sphere and coordinated nitrate ions: trans-[RuNO(NH3)4(H2O)](NO3)3 (I), trans-[RuNO(NH3)4(NO3)](NO3)2 (II), and fac-[RuNO(NH3)2(NO3)3] (III). Complex II has two polymorphs: monoclinic and tetragonal. The latter has been studied by X-ray crystallography.

The structure of trans-[RuNO(NH3)4(H2O)](NO3)3 (I) and trans-[RuNO(NH3)4(NO3)](NO3)2 (II) was determined by XRD. Crystallographic data are as follows: space group I41/a; a = b = 18.280(1) Å, c = 15.129(1) Å, R = 0.0244 (I), and space group Cm, a = 11.5620(3) Å, b = 7.9934(2) Å, c = 7.7864(2) Å, β = 127.124(1)°, R = 0.0139 (II). Interatomic distances for complex particles of fac- and mer- [RuNO(NH3)2(NO3)3] (III and IV, respectively) were determined by EXAFS.

The structure of the product formed on boiling [RuNO(NH3)(3)(NO2)(OH)]Cl center dot 0.5H(2)O in 3 M HNO3 is determined by XRD. The crystals belong to monoclinic symmetry. Crystallographic data for H11ClN6O8Ru are: a = 13.7924(4) , b = 6.9114(2) , c = 12.3577(4) , beta = 111.863(1)A degrees, V = 1093.27(6) (3), Z = 4, d (calc) = 2.185 g/cm(3), space group Cc. The structure is built of complex [RuNO(NH3)(3)(H2O)Cl](2+) cations and NO (3) (-) anions. The compound is studied by IR spectroscopy and X-ray phase analysis.

The structure of the product formed on boiling [RuNO(NH 3 ) 3 (NO 2 )(OH)]Cl·0.5H 2 O in 3 M HNO 3 is determined by XRD. The crystals belong to monoclinic symmetry. Crystallographic data for H 11 ClN 6 O 8 Ru are: a = 13.7924(4) Å, b = 6.9114(2) Å, c = 12.3577(4) Å, β = 111.863(1)°, V = 1093.27(6) Å 3 , Z = 4, d calc = 2.185 g/cm 3 , space group Cc . The structure is built of complex [RuNO(NH 3 ) 3 (H 2 O)Cl] 2+ cations and NO 3 − anions. The compound is studied by IR spectroscopy and X-ray phase analysis.

Methods for the synthesis of trans-diammino complexes [RuNO(NH3)2(NO2)2(OH)] (I) and [RuNO(NH3)2(H2O)(NO3)2](NO3)·H2O (II) are suggested. The compounds were studied by IR spectroscopy and X-ray phase and X-ray structural analyses. Crystal data: space group P-1; a = 6.2328(2) Å, b = 11.0488(3) Å, c = 11.0981(4) Å, α = 71.942(1)°, β = 83.291(1)°, γ = 86.877(1)° (I); space group P21; a = 6.6290(2) Å, b = 13.4389(5) Å, c = 7.0180(2) Å, β 114.281(1)° (II). Complex II readily lost some part of crystal water on storage in open air.