Luminescent and redox-active ruthenium(II) and osmium(II) complexes with a rigid allene-bridged polyphosphine †

Abstract

A series of monometallic and homo- and hetero-bimetallic Ru^II and Os^II complexes with the polyphosphines 1,1′-bis(diphenylphosphino)ethene (bppe) and 1,1′,3,3′-tetrakis(diphenylphosphino)allene (tppa) have been prepared and characterized by ³¹P-{¹H} NMR spectroscopy, elemental analysis and fast atom bombardment mass spectral analysis. Their ground-state properties (including electrochemical behavior and electronic absorption) and excited-state properties (including luminescence, quantum yields and MLCT excited state lifetimes) are reported herein. All complexes exhibit room-temperature luminescence, with long-lived ³MLCT excited states observed for monometallic and homobimetallic Os^II complexes with both bppe and tppa ligands. In the heterobimetallic Ru^II–Os^II complex [Ru(bpy)₂(µ-tppa)Os(bpy)₂][PF₆] (bpy = 2,2′-bipyridine) the luminescence of the Ru(bpy)₂-based unit is quenched by the connected Os(bpy)₂-based unit via energy transfer across the tppa spacer containing the allene bridge. Two overlapping one-electron oxidations, corresponding to the two M^II-based moieties (M = Ru or Os) bridged by the tppa spacer, are observed in the homobimetallic complexes.

References

1. J.-P. Sauvage, J.-P. Colin, J.-C. Chambron, S. Guillercz, C. Cudret, V. Balzani, F. Barigelletti, L. De Cola and L. Flamigni, Chem. Rev, 1994, 94, 993; V. Balzani, A. Juris, M. Venturi, S. Campagna and S. Serroni, Chem. Rev., 1996, 96, 759.
2. M. Brady, W. Weng, Y. Zhou, J. W. Seyler, A. J. Amoroso, A. M. Arif, M. Böhme, G. Frenking and J. A. Gladysz, J. Am. Chem. Soc., 1997, 119, 775; K. Wärnmark, J. A. Thomas, O. Heyke and J.-M. Lehn, Chem. Commun., 1996, 701.
3. T. J. Meyer, Pure Appl. Chem., 1986, 58, 1193; A. Harriman and R. Ziessel, Chem. Commun., 1996, 1707.
4. (a) F. Scandola, R. Argazzi, C. A. Bignozzi, C. Chiorboli, M. T. Indelli and M. A. Rampi, Coord. Chem. Rev., 1993, 125, 283; (b) P. Belser, R. Dux, M. Baak, L. De Cola and V. Balzani, Angew. Chem., Int. Ed. Engl., 1995, 34, 595; (c) A. I. Baba, H. E. Ensley and R. H. Schmehl, Inorg. Chem., 1995, 34, 1198.
5. B. Hong and J. V. Ortega, Angew. Chem., Int. Ed. Engl., 1998, in the press; B. Hong, Comments Inorg. Chem., 1998, in the press; F. A. Cotton and B. Hong, Prog. Inorg. Chem., 1992, 40, 179.
6. F. A. Cotton, B. Hong, M. Shang and G. G. Stanley, Inorg. Chem., 1993, 32, 3620.
7. V. Balzani and F. Scandola, Supramolecular Photochemistry, Horwood, Chichester, 1991.
8. (a) E. M. Kober, J. V. Caspar, B. P. Sullivan and T. J. Meyer, Inorg. Chem., 1988, 27, 4587; (b) S. R. Johnson, T. D. Westmoreland, J. V. Caspar, K. R. Barqawi and T. J. Meyer, Inorg. Chem., 1988, 27, 3195; (c) E. M. Kober, B. P. Sullivan, W. J. Dressick, J. V. Caspar and T. J. Meyer, J. Am. Chem. Soc., 1980, 102, 7383; (d) J. V. Caspar, E. M. Kober, B. P. Sullivan and T. J. Meyer, J. Am. Chem. Soc., 1982, 104, 630.
9. (a) R. G. Brewer, G. E. Jensen and K. J. Brewer, Inorg. Chem., 1994, 33, 124; (b) M. M. Richter and K. J. Brewer, Inorg. Chem., 1993, 32, 5762; (c) M. M. Richter and K. J. Brewer, Inorg. Chem., 1993, 32, 2827.
10. P.-W. Wang and M. A. Fox, Inorg. Chem., 1995, 34, 36.
11. (a) C. R. Arana and H. D. Abruna, Inorg. Chem., 1993, 32, 194; (b) V. Grosshenny, A. Harriman, M. Hissler and R. Ziessel, J. Chem. Soc., Faraday Trans., 1996, 92, 2223; (c) V. Grosshenny, A. Harriman, F. M. Romero and R. Ziessel, J. Phys. Chem., 1996, 100, 17 472; (d) V. Grosshenny, A. Harriman, M. Hissler and R. Ziessel, Angew. Chem., Int. Ed. Engl., 1995, 34, 1100.
12. (a) C. Creutz, M. Chou, L. Netzel, M. Okumura and N. Sutin, J. Am. Chem. Soc., 1980, 102, 1309; (b) F. Barigelletti, A. Juris, V. Balzani, P. Belser and A. von Zelewsky, Inorg. Chem., 1983, 22, 3335; (c) A. Juris, P. Belser, F. Barigelletti, A. von Zelewsky and V. Balzani, Inorg. Chem., 1986, 25, 256; (d) J. R. Winkler, T. L. Netzel, C. Creutz and N. Sutin, J. Am. Chem. Soc., 1987, 109, 2381; (e) Y. Fuchs, S. Lofters, T. Dieter, W. Shi, R. Morgan, T. C. Strekas, H. D. Gafney and A. D. Baker, J. Am. Chem. Soc., 1987, 109, 2691.
13. (a) J. V. Caspar, T. D. Westmoreland, G. H. Allen, P. G. Bradley, T. J. Meyer and W. H. Wooddruff, J. Am. Chem. Soc., 1984, 106, 3492; (b) J. N. Demas and D. G. Taylor, Inorg. Chem., 1979, 18, 3177; (c) K. Mandal, T. D. L. Pearson, W. P. Krug and J. N. Demas, J. Am. Chem. Soc., 1983, 105, 701.
14. (a) J. V. Caspar and T. J. Meyer, J. Am. Chem. Soc., 1983, 105, 5583; (b) J. V. Caspar, B. P. Sullivan and T. J. Meyer, Inorg. Chem., 1984, 23, 2104.
15. V. Balzani, F. Bolletta and F. Scandola, J. Am. Chem. Soc., 1980, 102, 2552.
16. F. Scandola and V. Balzani, J. Chem. Educ., 1983, 60, 814.
17. F. Barigelletti, L. Flamigni, V. Balzani, J.-P. Collin, J.-P. Sauvage, A. Sour, E. C. Constable and A. M. W. C. Thompson, J. Am. Chem. Soc., 1994, 116, 7692.
18. C. K. Ryu and R. H. Schmehl, J. Phys. Chem., 1989, 93, 7961; L. De Cola, V. Balzani, F. Barigelletti, L. Flamigni, P. Belser, A. von Zelewsky, M. Frank and F. Vögtle, Inorg. Chem., 1993, 32, 5228.
19. N. Sutin, Acc. Chem. Res., 1982, 15, 275.
20. M. Furue, T. Yoshidzumi, S. Kinoshita, T. Kushida, S. Nozakura and M. Kamachi, Bull. Chem. Soc. Jpn., 1991, 64, 1632; R. H. Schmehl, R. A. Auerbach and W. F. Walcholtz, J. Phys. Chem., 1988, 92, 6202; R. H. Schmehl, R. A. Auerbach, W. F. Walcholtz and C. M. Elliott, Inorg. Chem., 1986, 25, 2440.
21. T. Föster, Discuss. Faraday Soc., 1959, 27, 7.
22. This distance, the midpoint between the Ru and Os centers, in 2e is estimated using the space filling model in Insight/Discover of Biosym/MSI.
23. D. L. Dexter, J. Chem. Phys., 1953, 21, 836.
24. H. Schmidbaur and T. Pollok, Angew. Chem., Int. Ed. Engl., 1986, 25, 348.
25. H. Schmidbaur, S. Manhart and A. Schier, Chem. Ber., 1993, 126, 2389.
26. I. J. Colquhoun and W. McFarlane, J. Chem. Soc., Dalton Trans., 1982, 1915.
27. D. A. Buckingham, F. P. Dwyer, H. A. Goodwin and A. M. Sargeson, Aust. J. Chem., 1964, 17, 325; E. M. Kober, J. V. Casper, B. P. Sullivan and T. J. Meyer, Inorg. Chem., 1988, 27, 4587.