Structural and reactivity changes in ruthenium ammines induced by the NO ligand

Author(s)

Silva, Welter C. ; Castellano, Eduardo E. ^[2] ; Franco, Douglas W.

• Document type: Journal article
• Source: Polyhedron; v. 23, n. 6, p. 1063-1067, mar. 2004.
• Field of knowledge: Physical Sciences and Mathematics - Chemistry

Abstract

The crystal structure of [Ru(NH3)(5)(OH2)](2)(S2O6)(3) . 2H(2)O has been solved by X-ray diffraction techniques. The relevant average interatomic distances are Ru-(NH3)(eq) = 2.09 Angstrom, Ru-(NH3)(ax) = 2.08 Angstrom and Ru-(OH2)(ax) = 2.11 Angstrom. The aquation rate (k(H2O)) and the activation parameters for the reaction trans-[RuNO(NH3)(5)Cl](2+) + H2O (kH2O)--> trans-[RuNO(NH3)(4)(H2O)](3+) + Cl- have been calculated as 8.4 x 10(-6) s(-1) (0.10 mol L-1 CF3COOH, mu = 0.10 mot L-1, 40 degreesC), DeltaH(-1)(not equal), = 2.3 kcal mol(-1), DeltaS(-1)(not equal) = 24.0 cal deg(-1) mot and DeltaG(-1)(not equal) = 8.6 kcal mol(-1). A comparison between the structural data, kinetic and thermodynamic reactivities of [Ru(NH3)(5)(OH2)](3+) and trans-[RuNO(NH3)(4)(OH2)](3+) ions strongly suggests that the substitution of the trans NH3 ligand in the coordination sphere of [Ru(NH3)(5)(OH2)](2+) by NO confers a character of Ru(111) to the formally Ru(II) center. (AU)

• FAPESP's process: 99/07109-9 - Thermal and photochemical reactivity of ruthenium nitrosyl complexes: knowledge and control of the nitric oxide coordinated reactivity
• Grantee: Douglas Wagner Franco
• Support Opportunities: Research Projects - Thematic Grants