Resumo

SIGNINI, Roberta  e  MAZZETTO, Selma E.. Synthesis and Characterization of New Ammine Ru(II) Complexes Containing P(m-tol)₃, P(p-CH₃)₃ and P(OC₅H₁₁)₃. J. Braz. Chem. Soc. [online]. 2002, vol.13, n.5, pp.647-652. ISSN 1678-4790.  https://doi.org/10.1590/S0103-50532002000500017.

Direct reactions between [Ru(NH₃)₅(H₂O)](PF₆) ₂ (1) and P(m-tol)₃ (a), P(p-tol)₃ (b) and P(OC₅H₁₁)₃ (c) lead the complexes [Ru(NH₃)₅P(m-tol)₃](PF ₆)₂ (2a), trans-[Ru(NH₃)₄{P(p -tol)₃}₂](PF₆)₂ (3b) and trans-[Ru(NH₃)₄{P(OC₅H ₁₁)₃}₂](PF₆)₂ (3c) respectively. These complexes have been isolated as hexafluorophosphate salts and characterized by elemental analysis, cyclic voltammetry and UV-VIS spectra measurements. One ammonia ligand in 2a is displaced at the a specific rate of 4.3 x 10^-3 s^-1 (25 ^oC, μ = 0.10 mol L^-1). The aquo species trans-[Ru(NH₃)₄(L)H₂O] ²⁺ (L = P(p-tol)₃, 4b; L = P(OC₅H₁₁)₃, 4c) are generated by the substitution of one L ligand with H₂O, from trans-[Ru(NH₃)₄(L)₂]²⁺ with k_-1 = 2.7 x 10^-3 s^-1 [L = P(p-tol)₃, 3b] and 3.5 x 10^-3 s^-1 [L = P(OC₅H₁₁)₃ 3c] (25 ^oC, μ = 0.10 mol L^-1) (NaCF₃COO/CF₃COOH; C_H+ = 1.0 x 10^-3 mol L^-1). The formal reduction potentials for the species 3b, 3c and 2a are 0.50 ± 0.01V, 0.48 ± 0.01V and 0.50 ± 0.02V, respectively (vs SCE) [μ = 0.10 mol L^-1 ; NaCF₃COO; C_H+ = 1.0 x 10^-3 CF₃COOH]. The following reactions: [L = P(m-tol)₃, P(p-tol)₃ and P(OC₅H₁₁)₃] were studied and the calculated values for k₁, k_-1 and K_eq are 0.28 mol^-1 L s^-1, 0.06 s^-1, 4.67 mol^-1 L [L = P(m-tol)₃, 4a]; 0.25 mol^-1 L s^-1, 0.04 s^-1, 6.25 mol^-1 L [L = P(p-tol)₃, 4b]; 12.4 mol^-1 L s^-1, 5.8x10^-1 s^-1, and 21 mol^-1 L [L = P(OC₅H₁₁)₃, 4c], [25.0 ± 0.2 ^oC; m = 0.10 mol L^-1; NaCF₃COO; C_H+ = 1.0 x 10^-3 CF₃COOH].

Palavras-chave : ruthenium(II); ammine complexes; phosphine; phosphite ligands.

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