Molecular linear and quadratic non-linear optical properties of pentaammineruthenium complexes of coumarin dyes 

Abstract

The ruthenium(II) complex salts [Ru(NH₃)₅L][PF₆]₂ [L = coumarin 510 (C-510) 1 or coumarin 523 (C-523) 2] have been synthesized and fully characterized. Their Ru^III analogues [Ru(NH₃)₅L][PF₆]₃ (L = C-510 3 or C-523 4) have been prepared by oxidation of 1 or 2, respectively, with AgO₂CCF₃. Electronic spectroscopy and cyclic voltammetry have shown that the ruthenium centres exert an electron-withdrawing influence on the dyes, which is greater for C-523. The intense, low-energy intramolecular charge-transfer (i.c.t.) absorptions of the C-523 complexes displayed marked solvatochromism, whilst those of the C-510 complexes showed only very slight solvent dependence. Measurements of the first hyper-polarizability, β, by using the hyper-Rayleigh scattering technique at 1064 nm yielded large values in the range (120–420) × 10^-30 esu, the largest being for [Ru(NH₃)₅(C-523)][PF₆]₂2. These were enhanced by resonance via the i.c.t. excitations. Correction for resonance effects by using the two-level model afforded static hyper-polarizabilities (β₀) in the range 35–49 × 10^-30 esu, with [Ru(NH₃)₅(C-523)][PF₆]₃4 having the largest. The β₀ value for 4 was larger than that determined for C-523 via electric-field-induced second harmonic generation, indicating that complexation of a {Ru(NH₃)₅}³⁺ moiety enhanced the hyper-polarizability of this dye. This has been ascribed to the electron-withdrawing effect of the Ru^III centre.

References

1. S. R. Marder, in Inorganic Materials, eds. D. W. Bruce and D. O'Hare, Wiley, Chichester, 1992; D. R. Kanis, M. A. Ratner and T. J. Marks, Chem. Rev., 1994, 94, 195; N. J. Long, Angew. Chem., Int. Ed. Engl., 1995, 34, 21.
2. M. Schröder and T. A. Stephenson, in Comprehensive Coordination Chemistry, eds. G. Wilkinson, R. D. Gillard and J. A. McCleverty, Pergamon, Oxford, 1987, vol. 4.
3. W. M. Laidlaw, R. G. Denning, T. Verbiest, E. Chauchard and A. Persoons, Nature (London), 1993, 363, 58; Proc. SPIE, Int. Soc. Opt. Eng., 1994, 2143, 14.
4. C. Dhenaut, I. Ledoux, I. D. W. Samuel, J. Zyss, M. Bourgault and H. Le Bozec, Nature (London), 1995, 374, 339.
5. I. R. Whittall, M. G. Humphrey, A. Persoons and S. Houbrechts, Organometallics, 1996, 15, 1935; S. Houbrechts, K. Clays, A. Persoons, V. Cadierno, M. P. Gamasa and J. Gimeno, Organometallics, 1996, 15, 5266.
6. I. D. Morrison, R. G. Denning, W. M. Laidlaw and M. A. Stammers, Rev. Sci. Instrum., 1996, 67, 1445.
7. M. A. Mortazavi, A. Knoesen, S. T. Kowel, R. A. Henry, J. M. Hoover and G. A. Lindsay, Appl. Phys. B, 1991, 53, 287.
8. D. R. Yankelevich, A. Dienes, A. Knoesen, R. W. Schoenlein and C. V. Shank, IEEE J. Quantum Electron., 1992, 28, 2398.
9. S. M. Silence, J. C. Scott, F. Hache, E. J. Ginsburg, P. J. Jenkner, R. D. Miller, R. J. Twieg and W. E. Moerner, J. Opt. Soc. Am. B: Opt. Phys., 1993, 10, 2306.
10. C. R. Moylan, J. Phys. Chem., 1994, 98, 13513.
11. K. Clays and A. Persoons, Rev. Sci. Instrum., 1992, 63, 3285.
12. E. Hendrickx, K. Clays, A. Persoons, C. Dehu and J. L. Brédas, J. Am. Chem. Soc., 1995, 117, 3547.
13. J. P. Chang, E. Y. Fung and J. C. Curtis, Inorg. Chem., 1986, 25, 4233.
14. J. C. Curtis, B. P. Sullivan and T. J. Meyer, Inorg. Chem., 1983, 22, 224.
15. S. Houbrechts, K. Clays, A. Persoons, Z. Pikramenou and J.-M. Lehn, Chem. Phys. Lett., 1996, 258, 485.
16. M. Stähelin, D. M. Burland and J. E. Rice, Chem. Phys. Lett., 1992, 191, 245.
17. S. H. Kang, Y.-M. Jeon, K. Kim, S. Houbrechts, E. Hendrickx and A. Persoons, J. Chem. Soc., Chem. Commun., 1995, 635.
18. S. Maiorana, A. Papagni, E. Licandro, A. Persoons, K. Clays and S. Houbrechts, Gazz. Chim. Ital., 1995, 125, 377.
19. S. Stadler, G. Bourhill and C. Bräuchle, J. Phys. Chem., 1996, 100, 6927.
20. M. A. Pauley, H.-W. Guan, C. H. Wang and A. K.-Y. Jen, J. Chem. Phys., 1996, 104, 7821.
21. E. Hendrickx, C. Dehu, K. Clays, J. L. Brédas and A. Persoons, ACS Symp. Ser., 1995, 601, 82.
22. M. C. Flipse, R. de Jonge, R. H. Woudenberg, A. W. Marsman, C. A. van Walree and L. W. Jenneskens, Chem. Phys. Lett., 1995, 245, 297.
23. K. Clays, A. Persoons and L. De Maeyer, Adv. Chem. Phys., 1994, 85, 455.
24. S. J. Cyvin, J. E. Rauch and J. C. Decius, J. Chem. Phys., 1965, 43, 4083.
25. R. E. Clarke and P. C. Ford, Inorg. Chem., 1970, 9, 227.
26. R. E. Clarke and P. C. Ford, Inorg. Chem., 1970, 9, 495.
27. G. Jones II, W. R. Jackson, C. Choi and W. R. Bergmark, J. Phys. Chem., 1985, 89, 294.
28. A. N. Fletcher, D. E. Bliss and J. M. Kauffman, Opt. Commun., 1983, 47, 57.
29. G. A. Reynolds and K. H. Drexhage, Opt. Commun., 1975, 13, 222.
30. P. Ford, De F. P. Rudd, R. Gaunder and H. Taube, J. Am. Chem. Soc., 1968, 90, 1187.
31. M. S. Paley and J. M. Harris, J. Org. Chem., 1991, 56, 568.
32. CRC Handbook of Chemistry and Physics, ed. D. R. Lide, CRC Press, Boca Raton, FL, 75th edn., 1994.
33. V. Gutmann, The Donor-acceptor Approach to Molecular Interactions, Plenum, New York, 1978.
34. O. F. J. Noordman and N. F. Van Hulst, Chem. Phys. Lett., 1996, 253, 145.
35. J. L. Oudar and D. S. Chemla, J. Chem. Phys., 1977, 66, 2664; J. L. Oudar, J. Chem. Phys., 1977, 67, 446; J. Zyss and J. L. Oudar, Phys. Rev. A, 1982, 26, 2016.