The slow evaporation of an acetone solution containing trans-[Ru(NO)Py4(OH)]2+ cations and hexafluorophosphate anions results in the crystallization of trans-[Ru(NO)Py4(OH)](PF6)2 ⋅ (CH3)2CO (I). The reactions of trans‑[Ru(NO)Py4(OH)]Cl2 ⋅ H2O with solutions of chloric or hydrochloric acid followed by the evaporation of the reaction solutions at ambient temperature afford trans-[Ru(NO)Py4(H2O)](ClO4)3 (II) or [H5O2]2[Ru(NO)Py4Cl]Cl4 (III), respectively. The obtained chloride complex III is unstable and at ambient temperature eliminates hydrogen chloride to transform into trans-[Ru(NO)Py4Cl]Cl2 ⋅ 4H2O (IV). The crystal structures of compounds I and III are determined by X-ray structure analysis (CIF files ССDC nos. 1421042 (I) and 1421041 (III)).

After the addition of the saturated NaClO4 solution to a solution of trans-[Ru(NO)(NH3)(4)SO4]HSO(4)aEuro cent H2O, trans-[Ru(NO)(NH3)(4)SO4]ClO4 perchlorate salt (I) is obtained with the yield of similar to 80%. The heating of trans-[Ru(NO)(NH3)(4)(H2O)](HSO4)SO4 at a temperature of similar to 220 A degrees C results in a complete removal of coordination water and a partial removal of ammonia molecules. Successive treatment of the thermolysis product with sulfuric and hydrochloric acids yields [Ru(NO)(NH3)(4)SO4][Ru(NO)(NH3)(3)Cl(SO4)]HSO(4)aEuro cent H2O crystals (II). The single crystal X-ray diffraction method is used to determine the structure of the compounds obtained. For I: space group P2(1)/c, a = 6.6949(9) , b = 13.7049(19) , c = 12.8641(17) , beta = 101.028(4)A degrees; for II: space group D 2(1)/c, a = 14.1304(4) , b = 12.4908(3) ,, c = 11.6264(3) , beta = 94.1980(10)A degrees.

According to the data of 1H NMR spectroscopy, trans-hydroxochloro complexes containing from two to four pyridine molecules in the internal sphere are formed on the heating of a dilute aqueous solution of K2[Ru(NO)Cl5] with pyridine. The evaporation of the reaction solution with concentrated hydrochloric acid gives fac-[Ru(NO)(Py)2Cl3] (I) in a yield of ~90%. The structures of two crystalline modifications of this complex are determined by X-ray diffraction analysis (CIF files ССDС nos. 1452208 (Ia) and 1452207 (Ib)). IR spectroscopy shows that the irradiation of complex I (λ ~ 450 nm, T = 80 K) results in photoisomerization with the formation of the metastable state MS1 in which the nitroso group is coordinated by the oxygen atom. The activation parameters of the photoisomerization are determined from the data of differential scanning calorimetry (DSC). Compound trans-[Ru(NO)Py4(OH)]Cl2 ∙ H2O is isolated in a yield of ~70% on reflux of complex I with a pyridine excess in an aqueous solution, and the presence of molecules of water of crystallization in this compound is confirmed by thermal gravimetry (TG) and IR spectroscopy.

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 reaction of K-2[Ru(NO)Cl-5] with pyridine in aqueous ethanol at pH similar to 7-8 affords a nitrosoruthenium hydroxocomplex mer-[Ru(NO)Py3Cl(OH)]Cl center dot 1.5H(2)O (I) (yield similar to 55%). Treatment of hydroxocomplex I with hydrochloric acid at room temperature gives the aqua complex mer-[Ru(NO)Py3Cl(H2O)]Cl-2 center dot 2H(2)O center dot 0.5HCl (II). The structures of the compounds are determined by X-ray crystallography: I, space group P2(1)/n, a = 9.2292(4) , b = 11.7781(4) , c = 17.4915(7) , beta = 90.9560(10)A degrees, R = 4.84%; II, space group P-1, a = 7.3528(9) , b = 11.5793(11) , c = 13.6961(16) , alpha = 84.558(3)A degrees, beta = 87.668(4)A degrees, gamma = 74.146(4)A degrees, R = 6.22%. Compounds I and II are characterized by powder XRD, H-1 and C-13 NMR, and IR spectroscopy. The thermal decomposition of compound II in the inert atmosphere is examined by thermal analysis.

In treatment of trans-[Ru(NO)(NH3)4(OH)]Cl2 with concentrated sulfuric acid on heating trans-[Ru(NO)(NH3)4(SO4)](HSO4)·H2O (I) is obtained with a yield close to quantitative. In the interaction of the saturated solution of I with a saturated NaNO3 solution a trans-[Ru(NO)(NH3)4(SO4)]NO3·H2O (II) precipitate forms whose structure is determined by single crystal XRD: space group P212121, a = 6.8406(3) Å, b = 12.6581(5) Å, c = 13.3291(5) Å. A monodentately coordinated sulfate ion is in the trans-position to the nitroso group. Compound II is characterized by IR spectroscopy, powder XRD, and diffuse reflectance spectroscopy. The process of its thermolysis is studied; by differential scanning calorimetry the thermal effect of the dehydration reaction occurring on heating to 120°C (ΔH = 58.9 ± 1.5 kJ/mol) is estimated. The final product of the thermolysis of II is a mixture of Ru and RuO2.

The reaction of K2[Ru(NO)Cl5] with pyridine in aqueous ethanol at pH ∼ 7–8 affords a nitrosoruthenium hydroxocomplex mer-[Ru(NO)Py3Cl(OH)]Cl·1.5H2O (I) (yield ∼55%). Treatment of hydroxocomplex I with hydrochloric acid at room temperature gives the aqua complex mer-[Ru(NO)Py3Cl(H2O)]Cl2·2H2O·0.5HCl (II). The structures of the compounds are determined by X-ray crystallography: I, space group P21/n, a = 9.2292(4) Å, b = 11.7781(4) Å, c = 17.4915(7) Å, β = 90.9560(10)°, R = 4.84%; II, space group P-1, a = 7.3528(9) Å, b = 11.5793(11) Å, c = 13.6961(16) Å, α = 84.558(3)°, β = 87.668(4)°, γ = 74.146(4)°, R = 6.22%. Compounds I and II are characterized by powder XRD, 1H and 13C NMR, and IR spectroscopy. The thermal decomposition of compound II in the inert atmosphere is examined by thermal analysis.

We present a thermogravimetric study of the thermolysis of trans-[Ru(NO)(NH3)4(H2O)](HSO4)SO4 in a helium atmosphere. The intermediate product of thermolysis (at 186°C) is treated with a 2 M H2SO4 solution to obtain the first example of a sulfate ammine complex of nitrosoruthenium [Ru(NO)(NH3)4(SO4)](HSO4)·H2O (I) with a ∼70% yield. The product of higher temperature thermolysis (220°C) is treated with acids (H2SO4 and HCl) to obtain a triammine complex [Ru(NO)(NH3)3Cl(SO4)]·2H2O (II). The structure of the compounds is found by single crystal XRD: Pna21 space group, a = 10.8005(2) Å, b = 14.9032(3) Å, c = 7.7603(1) Å) (I) and P21/n space group, a = 8.9397(1) Å, b = 8.3276(1) Å, c = 13.8993(2) Å; β = 97.358(1)° (II).

We present a thermogravimetric study of the thermolysis of trans-[Ru(NO)(NH3)(4)(H2O)](HSO4)SO4 in a helium atmosphere. The intermediate product of thermolysis (at 186 degrees C) is treated with a 2 M H2SO4 solution to obtain the first example of a sulfate ammine complex of nitrosoruthenium [Ru(NO)(NH3)(4)(SO4)](HSO4)center dot H2O (I) with a similar to 70% yield. The product of higher temperature thermolysis (220 degrees C) is treated with acids (H2SO4 and HCl) to obtain a triammine complex [Ru(NO)(NH3)(3)Cl(SO4)]center dot 2H(2)O (II). The structure of the compounds is found by single crystal XRD: Pna2(1) space group, a = 10.8005(2) angstrom, b = 14.9032(3) angstrom, c = 7.7603(1) angstrom) (I) and P2(1)/n space group, a = 8.9397(1) angstrom, b = 8.3276(1) angstrom, c = 13.8993(2) angstrom; beta = 97.358(1)degrees (II).

The structure of the interaction products of (NH4)2[Ru(NO)Cl5] solution with ammonium acetate on heating is studied. The crystal structure of the [Ru(NO)(NH3)3(H2O)Cl][Ru(NO)(NH3)3(OH)Cl] × [Ru(NO)(NH3)Cl4]2Cl-2H2O compound (compound I) containing a previously unknown anion of the nitrosomonoammine series is determined: Cc space group; a = 33.530(7) Å, b = 8.202(2) Å, c = 11.844(2) Å; β= 101.54(3)°.

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.

A DTA study of thermal decomposition of (NH4)2[Ru(NO)Cl5] in helium atmosphere has been carried out, a synthetic procedure for preparation of the trans-diammine complex mer-[Ru(NO)(NH3)2Cl3] (I) with yield ∼70% has been developed. On re-crystallization of I from aqueous solution a trans-aquanitroso complex [Ru(NO)(NH3)2Cl2(H2O)]Cl·H2O (II) has been isolated. The structures of the compounds have been determined by single crystal X-ray diffraction: space group Pbcn, a = 6.607(1) Å b = 11.255(2) Å c = 9.878(2) Å (I) and space group Ima2, a = 8.3032(3) Å, b = 8.0890(2) Å, c = 15.9192(5) Å II).

A DTA study of thermal decomposition of (NH4)(2)[Ru(NO)Cl-5] in helium atmosphere has been carried out, a synthetic procedure for preparation of the trans-diammine complex mer-[Ru(NO)(NH3)(2)Cl-3] (I) with yield similar to 70% has been developed. On re-crystallization of I from aqueous solution a trans-aquanitroso complex [Ru(NO)(NH3)(2)Cl-2(H2O)]Cl center dot H2O (II) has been isolated. The structures of the compounds have been determined by single crystal X-ray diffraction: space group Pbcn, a = 6.607(1) A... b = 11.255(2) A... c = 9.878(2) A... (I) and space group Ima2, a = 8.3032(3) A..., b = 8.0890(2) A..., c = 15.9192(5) A... II).

The salt of cobalt hexacyanide with the photochromic mononitrosyl cation [RuNO(NH 3 ) 5 ] 3+ with the composition [RuNO(NH 3 ) 5 ][Co(CN) 6 ] was synthesized. Single crystals of the salt were grown, and the crystal structure was solved. The photochromic properties were studied by differential scanning calorimetry (DSC).

The nitrosation of [Ru(NH 3 ) 6 ] 2+ in hydrochloric acid and alkaline ammonia media has been studied; the patterns of interconversion of ruthenium complexes in reaction solutions have been proposed. In both cases, nitrogen(II) oxide acts as the nitrosation agent. The procedure for the synthesis of [Ru(NO)(NH 3 ) 5 ]Cl 3 · H 2 O (yield 75–80%), the main nitrosation product of [Ru(NH 3 ) 6 ] 2+ , has been optimized. Thermolysis of [Ru(NO)(NH 3 ) 5 ]Cl 3 · H 2 O in a helium atmosphere has been studied; the intermediates have been identified. One of these products is polyamidodichloronitrosoruthenium(II) whose subsequent decomposition gives an equimolar mixture of ruthenium metal and dioxide. The structure of trans -[RuNO(NH 3 ) 4 Cl]Cl 2 , formed in the second stage of thermolysis and as a by-product in the nitrosation of [Ru(NH 3 ) 6 ]Cl 2 , has been determined by X-ray diffraction.

The reaction between [RuNO(NH 3 ) 2 (NO 2 ) 2 OH] and an excess of 3 M HCl leads to denitration of the starting complex and precipitation of [Ru(NO)(NH 3 ) 2 Cl 3 ]. Crystals of the tittle complex have been obtained by evaporation of the mother liquor at ambient temperature. The crystal structure of the product has been determined. The linear nitroso group and a water molecule are coordinated in the trans positions, three nitrogen atoms from NO and NH 3 ligands occupy the coordination octahedron face.

The synthesis and characterization of two novel complexes formed by the photochromic mononitrosyl cations [RuNO(NH_3)_5]^3+ and [RuNO(NH_3)_4OH]^2+ , and the paramagnetic polyoxometalate (POM) anion [Cr(OH)_6Mo_6O_18]^3- are reported. Compound [RuNO(NH_3)_4OH]_3[Cr(OH)_6Mo_6O_18]_2·15H_2O ( 1) was characterized by X-ray diffraction, it crystallizes in the triclinic space group, P −1 , a = 10.5858(2), b = 11.0407(2), c = 16.8077(4) Å, α=76.9192(7), β = 73.7736(7), γ = 84.090(1)^∘ , R =0.0636 for 16046 reflections with I > 2 σ ( I ). Compound 1 and compound [RuNO(NH_3)_5][Cr(OH)_6Mo _6O_18]·8H_2O , ( 2) are paramagnetic in the whole temperature range 2–300 K. The metastable state (MSI) was detected in 1 by differential scanning calorimetry (DSC). The decay curve shows two peaks in the heat release at about 245 and 265 K with activation energies and frequencies values equal to 0.72 eV and 3 × 10 11 s −1 and 0.67 eV and 7 × 10 11 s −1 for the high- and low-temperature peak, respectively [see F. Bottomley ( J. Chem. Soc. Dalton Trans . 1600, 1997)].