Anion interactions with (polypyridyl)ruthenium complexes, and their importance in the cation-exchange chromatographic separation of stereoisomers of dinuclear species †

Abstract

The separation of the ligand-bridged dinuclear complex cation [{(Me₂bpy)₂Ru}₂(µ-bpm)]⁴⁺ (Me₂bpy = 4,4′-dimethyl-2,2′-bipyridine; bpm = 2,2′-bipyrimidine) into its two diastereoisomeric forms, meso and rac, by cation-exchange chromatography has been investigated, using a wide range of organic counter anions (aromatic and aliphatic) in the aqueous eluents. ¹H NMR titration studies not only confirm association between the complex cation and the counter anions in solution, but also reveal differential associations with the two diastereoisomers of [{(Me₂bpy)₂Ru}₂(µ-bpm)]⁴⁺. Analogous interactions are also evident with mononuclear species, [Ru(pp)₃]²⁺, where pp is a bidentate ligand such as Me₂bpy, 1,10-phenanthroline (phen) or 2,2′-bipyridine (bpy): from ¹H NMR titration studies, the first association with a number of organic anions has a stability constant in the order of 100 dm³ mol^–1 in aqueous solution. This association also affects the emission from the MLCT excited state of the monomers, with up to a 10% enhancement in the luminescence.

References

1. A. Juris, S. Barigelletti, S. Campagna, V. Balzani, P. Belser and A. von Zelewsky, Coord. Chem. Rev., 1988, 84, 85 and refs. therein.
2. V. Balzani and F. Scandola, Supramolecular Photochemistry, Ellis Horwood, Chichester, 1991, p. 427.
3. P. Frediani, M. Bianchi, A. Salvini, R. Guarducci, L. C. Carluccio and F. Piacenti, J. Org. Chem., 1995, 498, 187.
4. P. D. Beer, N. C. Fletcher and T. Wear, Polyhedron, 1996, 15, 1339.
5. F. Szemes, D. Hesek, Z. Chen, S. W. Dent, M. G. B. Drew, A. J. Goulden, A. R. Graydon, A. Grieve, R. J. Mortimer, T. Wear, J. S. Weightman and P. D. Beer, Inorg. Chem., 1996, 35, 5868.
6. L. F. Cooley, S. L. Larson, C. M. Elliott and D. F. Kelley, J. Phys. Chem., 1991, 95, 10694.
7. J. D. Petersen, S. L. Gahan, S. C. Rasmussen and S. E. Ronco, Coord. Chem. Rev., 1994, 132, 15.
8. E. Zahavy, M. Seiler, S. Marx-Tibbon, E. Joselevich, I. Willner, H. Durr, D. O'Connor and A. Harriman, Angew. Chem., 1995, 107, 1012; Angew. Chem., Int. Ed. Engl., 1995, 34, 1005.
9. J.-P. Collin, S. Guillerez, J.-P. Sauvage, F. Barigelletti, L. Flamigni, L. De Cola and V. Balzani, Coord. Chem. Rev., 1991, 111, 291.
10. R. Argazzi, C. A. Bignozzi, T. A. Heimer, F. N. Castellano and G. J. Meyer, J. Am. Chem. Soc., 1995, 117, 11815.
11. A. Kirsch-De Mesmaeker, J.-P. Lecomte and J. M. Kelly, Top. Curr. Chem., 1996, 177, 25.
12. A. M. Pyle and J. K. Barton, Prog. Inorg. Chem., 1990, 38, 413.
13. C. Turro, S. Niu, J. K. Barton and N. J. Turro, Inorg. Chim. Acta, 1996, 252, 333.
14. A. von Zelewsky, Chimia, 1994, 48, 331.
15. F. R. Keene, Coord. Chem. Rev., 1997, 166, 121.
16. F. R. Keene, Chem. Soc. Rev., 1998, 27, 185.
17. T. J. Rutherford and F. R. Keene, Inorg. Chem., 1997, 36, 3580.
18. T. J. Rutherford, O. Van Gijte, A. Kirsch-De Mesmaeker and F. R. Keene, Inorg. Chem., 1997, 36, 4465.
19. T. J. Rutherford and F. R. Keene, Inorg. Chem., 1997, 36, 2872.
20. T. J. Rutherford, M. G. Quagliotto and F. R. Keene, Inorg. Chem., 1995, 34, 3857.
21. D. A. Reitsma and F. R. Keene, J. Chem. Soc., Dalton Trans., 1993, 2859.
22. B. T. Patterson and F. R. Keene, Inorg. Chem., 1998, 37, 645.
23. T. J. Rutherford, PhD Thesis, James Cook University, 1997.
24. G. H. Searle, Aust. J. Chem., 1977, 30, 2625.
25. Y. Yoshikawa and K. Yamasaki, Coord. Chem. Rev., 1979, 28, 205.
26. H. Yoneda, J. Chromatogr., 1984, 313, 59.
27. N. C. Fletcher, P. C. Junk, D. A. Reitsma and F. R. Keene, J. Chem. Soc., Dalton Trans., 1998, 133.
28. P. D. Beer, Chem. Commun., 1996, 689.
29. B. L. Hauenstein, W. J. Dressick, T. B. Gilbert, J. N. Demas and B. A. DeGraff, J. Phys. Chem., 1984, 88, 1902.
30. S. W. Snyder, S. L. Buell, J. N. Demas and B. A. DeGraff, J. Phys. Chem., 1989, 93, 5265.
31. K. R. Gopidas, A. R. Leheny, G. Caminati, N. J. Turro and D. A. Tomalia, J. Am. Chem. Soc., 1991, 113, 7335.
32. J. W. Park, M.-H. Kim, S. H. Ko and Y. H. Paik, J. Phys. Chem., 1993, 97, 5424.
33. D. Y. Chu and J. K. Thomas, J. Phys. Chem., 1985, 89, 4065.
34. D. Meisel and M. S. Matheson, J. Am. Chem. Soc., 1977, 6577.
35. G. L. Duveneck, C. V. Kumar, N. J. Turro and J. K. Barton, J. Phys. Chem., 1988, 92, 2028.
36. C. Turro, A. Evenzahav, S. H. Bossmann, J. K. Barton and N. J. Turro, Inorg. Chim. Acta, 1996, 243, 101.
37. J. P. Rehmann and J. K. Barton, Biochemistry, 1990, 29, 1701.
38. A. M. Pyle, J. P. Rehmann, R. Meshoyrer, C. V. Kumar, N. J. Turro and J. K. Barton, J. Am. Chem. Soc., 1989, 111, 3051.
39. J. K. Barton, J. M. Goldberg, C. V. Kumar and N. J. Turro, J. Am. Chem. Soc., 1986, 108, 2081.
40. M. J. Hynes, J. Chem. Soc., Dalton Trans., 1993, 311.
41. I. M. Atkinson, unpublished work.
42. C. S. Wilcox, Frontiers in Supramolecular Organic Chemistry and Photochemistry, ed. H.-J. Schneider and H. Dürr, VCH Verlagsgesallschaft, Weinheim, 1991, p. 123.
43. C. A. Hunter and J. K. M. Sanders, J. Am. Chem. Soc., 1990, 112, 5525.
44. T. J. Rutherford, P. A. Pellegrini, J. Aldrich-Wright, P. C. Junk and F. R. Keene, Eur. J. Inorg. Chem, 1998, 1677.
45. G. J. Kavarnos, Fundamentals of Photoinduced Electron Transfer, VCH, New York, 1993.
46. A. Shulman and F. P. Dwyer, Chelating Agents and Metal Chelates, ed. F. P. Dwyer and D. P. Mellor, Academic Press, New York, 1964, pp. 383–439.
47. P. Lincoln, A. Broo and B. Nordén, J. Am. Chem. Soc., 1996, 118, 2644.