Cycloplatination of aryl and ferrocenyl oximes by cis-[PtCl₂(OSMe₂)₂] affording expected platinum(II) and unexpected platinum(IV) products

Abstract

Acetophenone, benzamide, ferrocenyl methyl ketone and ferrocenecarboxamide oximes reacted with cis-[PtCl₂(dmso)₂] (dmso = dimethyl sulfoxide) in refluxing methanol to afford the expected platina(II)cycles N,S-trans-[Pt(C–N)Cl(dmso)], where C–N stands for the corresponding cycloplatinated organic ligand. The highest yield of 51% was observed in the case of the acetophenone oxime complex. The structures of the complexes were established on the basis of analytical and ¹H NMR data, and confirmed by an X-ray diffraction analysis of the platinated ferrocenyl methyl ketone oxime. A cyclic voltammetry study of the latter indicated that cyclometallation decreases the redox potential of the ferrocene unit by ca. 200 mV. The reaction of a bulkier analog of acetophenone oxime, viz. 2-methyl-1-phenylbutan-1-one oxime, resulted in the formation of the unexpected platinum(IV) complex fac-[Pt(C–N)Cl₃(SMe₂)] revealing a unique combination of oxidative cycloplatination and dmso-deoxygenation processes which occur under rather mild conditions. The composition of the platinum(IV) compound was established by X-ray crystallography. The Pt–Cl bond distance trans to the phenyl carbon [2.464(4) Å] is rather large. As a result, the trans chloro ligand undergoes rapid solvolysis in aqueous solution, causing a pH drop. The deoxygenation of dimethyl sulfoxide that occurs within the metal co-ordination sphere can be viewed as a model of the action of the metal-dependent redox enzyme dimethyl sulfoxide reductase.

References

1. A. D. Ryabov, L. G. Kuz'mina, N. V. Dvortsova, D. J. Stufkens and R. van Eldik, Inorg. Chem., 1993, 32, 3166.
2. A. D. Ryabov and R. van Eldik, Angew. Chem., Int. Ed. Engl., 1994, 33, 783.
3. E. V. Krooglyak, G. M. Kazankov, S. A. Kurzeev, V. A. Polyakov, A. N. Semenov and A. D. Ryabov, Inorg. Chem., 1996, 35, 4804.
4. A. D. Ryabov, Chem. Rev., 1990, 90, 403.
5. A. C. Cope and E. C. Friedrich, J. Am. Chem. Soc., 1968, 90, 909.
6. H. Onoue, K. Minami and K. Nakagawa, Bull. Chem. Soc. Jpn., 1970, 43, 3480.
7. P. R. R. Ranatunge-Bandarage, B. H. Robinson and J. Simpson, Organometallics, 1993, 13, 500.
8. (a) R. Annunziata, S. Cenini, F. Demartin, G. Palmisano and S. Tollari, J. Organomet. Chem., 1995, 496, C1; (b) Y. J. Wu, L. Ding, H. X. Wang, Y. H. Liu, H. Z. Yuan and X. A. Mao, J. Organomet. Chem., 1997, 535, 49.
9. J. H. Price, A. N. Williamson, R. F. Schramm and B. B. Wayland, Inorg. Chem., 1972, 11, 1280.
10. F. Tiemann, Ber. Bunsenges. Phys. Chem., 1887, 17, 126.
11. E. Beckman, Chem. Ber., 1890, 23, 1680; Liebigs Ann. Chem., 1909, 365, 200.
12. P. D. Bartlett and C. H. Stauffer, J. Am. Chem. Soc., 1935, 57, 2580.
13. G. M. Sheldrick, Acta Crystallogr., Sect. A, 1990, 46, 467.
14. G. M. Sheldrick, SHELXL 93, Program for the Refinement of Crystal Structures, University of Göttingen, 1993.
15. A. Q. Hussein and H. A. Hodali, Synth. React. Inorg. Metal Org. Chem., 1988, 18, 365.
16. C. López, R. Bosque, X. Solans and M. Font-Bardía, J. Organomet. Chem., 1997, 539, 99.
17. (a) M. Berardini, T. J. Emge and J. G. Brennan, Inorg. Chem., 1993, 32, 2724; (b) C. E. L. Headford, R. Mason, P. R. Ranatunge-Bandarage, B. H. Robinson and J. Simpson, J. Chem. Soc., Chem. Commun., 1990, 601; (c) K. Lövqvist and Å. Oskarsson, Acta Crystallogr., Sect. C, 1992, 48, 2073; (d) P. Bitha, G. O. Morton, T. S. Dunne, E. F. D. Santos, Y.-i. Lin, S. R. Boone, R. C. Haltiwanger and C. G. Pierpont, Inorg. Chem., 1990, 29, 645; (e) B. Viossat, P. Khodadad and N. Rodier, Acta Crystallogr., Sect. C, 1991, 47, 1316; (f) C. G. Arena, G. Bruno, G. De Munno, E. Rotondo, D. Drommi and F. Faraone, Inorg. Chem., 1993, 32, 1601; (g) R. E. Cramer and M. J. J. Carrie, Inorg. Chem., 1993, 32, 3509; (h) T. Al-Allaf, P. Castan, R. Turpin, S. Wimmer and G. Bernardinelli, Transition Met. Chem., 1992, 17, 579; (i) P. R. R. Ranatunge-Bandarage, N. W. Duffy, S. M. Johnston, B. H. Robinson and J. Simpson, Organometallics, 1994, 13, 511.
18. A. D. Ryabov, G. M. Kazankov, A. K. Yatsimirsky, V. A. Polyakov, L. G. Kuz'mina, O. Yu. Burtseva and N. A. Dvortsova, Inorg. Chem., 1992, 31, 3083.
19. M. Calligaris and O. Carugo, Coord. Chem. Rev., 1996, 153, 83.
20. A. D. Ryabov, L. G. Kuz'mina, V. A. Polyakov, G. M. Kazankov, E. S. Ryabova, M. Pfeffer and R. van Eldik, J. Chem. Soc., Dalton Trans., 1995, 999.
21. R. Bosque, C. López and J. Sales, Inorg. Chim. Acta, 1996, 244, 141.
22. P. S. Braterman, J.-i. Song, F. M. Wimmer, S. Wimmer, W. Kaim, A. Klein and R. D. Peacock, Inorg. Chem., 1992, 31, 5084; G. Minghetti, M. I. Pilo, G. Sanna, R. Seeber, S. Stoccoro and F. Laschi, J. Organomet. Chem., 1993, 452, 257.
23. A. D. Ryabov, Angew. Chem., Int. Ed. Engl., 1991, 30, 931; Ross. Khim. Zh., 1995, 139.
24. C. Hansch, A. Leo and R. W. Taft, Chem. Rev., 1991, 91, 165.
25. U. Bierbach, T. W. Hambley, J. D. Roberts and N. Farell, Inorg. Chem., 1996, 25, 4865.
26. G. van Koten, J. Terheijden, J. A. M. van Beek, I. C. M. Wehman-Ooyevaar, F. Muller and C. H. Stam, Organometallics, 1990, 9, 903.
27. W. N. Hunter, K. W. Muir and D. W. Sharp, Acta Crystallogr., Sect. C, 1986, 42, 961.
28. S. Chattopadhyay, C. Sinha, P. Basu and A. Chakravorty, Organometallics, 1991, 10, 1135.
29. A. R. Khokhar, S. Shamsuddin and Q. Xu, Inorg. Chim. Acta, 1994, 219, 193.
30. K. Nakamoto, Infrared Spectra of Inorganic and Coordination Compounds, Wiley, New York, London, 1963.
31. A. J. Canty, R. T. Honeyman, A. S. Roberts, P. R. Traill, R. Colton, B. W. Skelton and A. H. White, J. Organomet. Chem., 1994, 471, C8; A. J. Canty, S. D. Fritsche, H. Jin, B. W. Skelton and A. H. White, J. Organomet. Chem., 1995, 490, C18; A. J. Canty and G. van Koten, Acc. Chem. Res., 1995, 28, 406.
32. V. Yu. Kukushkin, Coord. Chem. Rev., 1995, 139, 375.
33. J. H. Weiner, R. A. Rothery, D. Sambasivarao and C. A. Trieber, Biochim. Biophys. Acta, 1992, 1102, 1.