cis- and trans-nitrosyltetraammineruthenium(II). Spectral and electrochemical properties and reactivity

Abstract

A synthetic route was developed for the preparation of trans-[Ru(NH₃)₄(NO)X]ⁿ⁺, where X = isonicotinamide (isn), pyrazine (pyz) or sulfite, and cis-[Ru(NH₃)₄(NO)(NO₂)]²⁺. The complexes have been characterized by elemental analysis, UV/VIS, infrared, ¹H NMR and ESR spectroscopies, molar conductance measurements and cyclic voltammetry. All showed ν(NO) in the range characteristic of metal-co-ordinated NO⁺ and do not exhibit any ESR signal, consistent with the formulation of Ru^II–NO⁺. The equilibrium constants K_eq for the reaction trans-[Ru(NH₃)₄(NO)X]³⁺ + 2OH^– ⇌ trans-[Ru(NH₃)₄(NO₂)X]⁺ + H₂O are 2.5 × 10⁸ and 6 × 10⁸ dm⁶ mol^–2 for X = isn or pyz. Cyclic voltammograms of the complexes in aqueous solution exhibited reversible one-electron waveforms in the potential range –0.13 to –0.38 V vs. SCE, which were assigned to the [Ru(NH₃)₄(NO)X]ⁿ⁺ → [Ru(NH₃)₄(NO)X]^(n–1)+ process. Nitric oxide and trans-[Ru(NH₃)₄(H₂O)X]²⁺ are the final products of the reaction between Eu^II and trans-[Ru(NH₃)₄(NO)X]³⁺, L = isn or pyz. Ab initio molecular orbital calculations performed for trans-[Ru(NH₃)₄(NO)(pyz)]³⁺ and trans-[Ru(NH₃)₄(NO)(pyz)]²⁺, and the products of the trans-[Ru(NH₃)₄(NO)(pyz)]³⁺ one-electron electrochemical or chemical reduction, strongly suggest the added electron is localized mainly on the nitrosyl ligand. A correlation was observed between ν(NO) and E_½ for the reversible reduction wave. These results indicate that the nitric oxide reduction is facilitated by strong π-acceptor ligands trans to the NO. Nitric oxide and trans-[Ru(NH₃)₄(H₂O)X]³⁺ were formed when solutions containing trans-[Ru(NH₃)₄(NO)X]³⁺ were irradiated in the range 310–370 nm.

References

1. (a) R. Eisenberg and C. D. Meyer, Acc. Chem. Res., 1975, 8, 26; (b) M. H. Thiemens and W. C. Trogler, Science, 1991, 251, 932; (c) ACS Symp. Ser., 1995, 587; (d) G. B. Ritcher-Addo and P. Legzdins, Metal Nitrosyls, Oxford University Press, New York, 1992.
2. E. R. S. Winter, J. Catal., 1971, 22, 158; F. Bottomley, Acc. Chem. Res., 1978, 11, 158; Reactions of Coordinated Ligands, ed. P. S. Braterman, Plenum, New York, 1989, vol. 2; Methods in Nitric Oxide Research, eds. M. Feelisch and J. S. Stamler, Wiley, Chichester, 1996.
3. D. E. Koshland, jun., Science, 1992, 258, 1861; P. C. Ford, D. A. Wink and D. M. Stanbury, FEBS Lett., 1993, 326, 1; D. A. Wink and P. C. Ford, Methods Enzymol., 1995, 7, 14; R. Butler and D. L. H. Williams, Chem. Soc. Rev., 1993, 233; D. R. Arnelle and J. S. Stamler, Arch. Biochem. Biophys., 1995, 318, 279; D. S. Bohle and C. H. Hung, J. Am. Chem. Soc., 1995, 117, 9584.
4. M. Fontecave and J. L. Pierre, Bull. Soc. Chim. Fr., 1994, 131, 620.
5. M. J. Clarke and J. B. Gaul, Struct. Bonding (Berlin), 1993, 81, 144; P. J. Sadler, Adv. Inorg. Chem., 1991, 36, 1 and refs. therein; K. D. Karlin and Z. Tyeklar(Editors), Bionorganic Chemistry of Copper, Chapman and Hall, New York, 1993; P. Legzdins, S. J. Rettig and S. F. Sayers, J. Am. Chem. Soc., 1994, 116, 12 105 and refs. therein; N. A. Davies, M. T. Wilson, E. Slade, S. P. Fricker, B. A. Murrer, N. A. Powell and G. R. Henderson, Chem. Commun., 1997, 47.
6. M. J. Clarke, J. Am. Chem. Soc., 1978, 100, 5068.
7. E. A. M. F. Dahmen, Electroanalysis: Theory and Application in Aqueous and Non Aqueous Media and Automated Chemical Control, Elsevier, London, 1986.
8. S. E. Mazzetto, E. Tfouni and D. W. Franco, Inorg. Chem., 1996, 35, 3509.
9. S. Pell and J. N. Armor, Inorg. Chem., 1973, 12, 873.
10. S. S. Isied and H. Taube, Inorg. Chem., 1974, 13, 1545.
11. G. M. Brown, J. E. Sutton and H. Taube, J. Am. Chem. Soc., 1978, 100, 2767.
12. A. D. Becke, Phys. Rev. A, 1988, 38, 3098.
13. C. Lee, W. Yang and R. G. Parr, Phys. Rev. B, 1988, 37, 785.
14. GAUSSIAN 94, Revision B.2, M. J. Frisch, G. W. Trucks, H. B. Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Cheesman, T. Keith, G. A. Petersson, J. A. Montgomery, K. Raghavachari, M. A. Al-Laham, V. G. Zakrzewski, J. V. Ortiz, J. B. Foresman, C. Y. Peng, P. Y. Ayala, W. Chen, M. W. Wong, J. L. Andres, E. S. Replogle, R. Gomperts, R. L. Martin, D. J. N. Fox, J. S. Binkley, D. J. Defrees, J. Baker, J. P. Stewart, M. Head-Gordon, O. C. Gonzalez and J. A. Pople, Gaussian, Inc., Pittsburgh, PA, 1995.
15. N. Godbout, D. R. Saluhub, J. Andzelm and E. Wimmer, Can. J. Chem., 1992, 70, 560.
16. HYPERCHEM 4, Hypercube, Inc., Toronto, CA, 1994.
17. J. H. Enemark and R. D. Feltham, Coord. Chem. Rev., 1974, 13, 339.
18. (a) J. N. Armor and M. Z. Hoffman, Inorg. Chem., 1975, 14, 444; (b) R. W. Callahan, G. M. Brown and T. J. Meyer, J. Am. Chem. Soc., 1975, 97, 894; (c) R. W. Callahan and T. J. Meyer, Inorg. Chem., 1977, 16, 574; (d) D. W. Pipes and T. J. Meyer, Inorg. Chem., 1984, 23, 2466; (e) I. A. Bagatin and H. E. Toma, Spectrosc. Lett., 1996, 29, 1409.
19. L. G. F. Lopes, E. E. Castellano, J. Z.-Schepctor, C. U. Davanzo, M. J. Clarke, A. Wieraszko and D. W. Franco, Inorg. Chem., submitted.
20. R. Benedix and A. Vogler, Inorg. Chim. Acta, 1993, 204, 189.
21. P. T. Manoharan and H. B. Gray, J. Am. Chem. Soc., 1965, 87, 3340.
22. A. F. Schreiner, P. J. Hauser, S. W. Lin, E. A. Hopcus, D. J. Hamm and J. D. Gunter, Inorg. Chem., 1972, 11, 880.
23. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, 4th edn., Wiley, New York, 1986.
24. S. C. Silva, A. B. P. Lever and D. W. Franco, unpublished work.
25. J. W. Palmer and F. Basolo, J. Inorg. Nucl. Chem., 1960, 15, 279.
26. J. Mastone and J. N. Armor, J. Inorg. Nucl. Chem., 1975, 37, 473.
27. C. G. Kuehn and S. S. Isied, Prog. Inorg. Chem., 1980, 27, 153 and refs. therein.
28. G. J. Kubas and P. J. Vergamini, Inorg. Chem., 1981, 20, 2667.
29. R. C. Elder and M. Trkula, Inorg. Chem., 1977, 16, 1048.
30. C. A. Reed and W. R. Roper, J. Chem. Soc., Dalton Trans., 1972, 1243.
31. F. Bottomley, Acc. Chem. Res., 1978, 11, 158.
32. A. Albert and P. E. Serjeant, The Determination of Ionization Constants, Chapman and Hall, Edinburgh, 1971.
33. J. B. Godwin and T. J. Meyer, Inorg. Chem., 1971, 10, 2150.
34. S. S. S. Borges, C. U. Davanzo, E. E. Castellano, J. Z.-Schepctor, S. C. Silva and D. W. Franco, Inorg. Chem., submitted.
35. F. Bedioui, S. Trevin and J. Devynck, J. Electroanal. Chem. Interfacial Electrochem., 1994, 377, 295; V. Hampl, C. L. Walters and S. L. Archer, Methods in Nitric Oxide Research, eds. M. Feelisch and J. S. Stamler, Wiley, Chichester, 1996, ch. 21.
36. S. S. S. Borges, M. G. Gomes, L. C. G. Vasconcellos, H. A. S. Silva, R. M. Carlos, S. C. Silva and D. W. Franco, Program and Abstracts of the Eighth Inter-American Photochemical Society Conference, Foz do Iguaçu, 19–24th May, 1996, p. 81.
37. W. A. Cramer and D. B. Knaff, in Energy Transduction in Biological Membranes: A textbook of Bioenergetics, ed. Charles R. Cantor, Springer, New York, 1990, p. 334.
38. J. A. Rodriguez, A. Souza-Torsoni, D. W. Franco and M. Haun, XXVI^a Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular-SBBQ, Caxambú, 3rd–6th May, 1997, S-32.