Redox behavior of cerium in heteropolyoxotungstate complexes

Abstract

In situ XAFS spectroelectrochemistry is used to characterize the oxidation state and coordination environment of cerium in two different heteropolytungstates, the Wells–Dawson [Ce(α-2-P₂W₁₇O₆₁)₂]^17– anion, and the Preyssler [CeP₅W₃₀O₁₁₀]^12– anion. Ce(III), coordinated to the Wells–Dawson framework, is oxidized at an applied potential of +0.37 V vs. Ag/AgCl. This is 1.15 V less than the Ce(IV)/Ce(III) standard reduction potential of +1.52 V vs. Ag/AgCl, demonstrating that Ce(IV) is stabilized in this heteropolyanion. In contrast, Ce(III) when encapsulated in the Preyssler anion is not oxidized at potentials higher than would be required for its oxidation in a non-complexing medium, indicating a stabilization of Ce(III). This is despite the 12– charge on the anion. The different redox behavior of Ce is understood in terms of the different coordination environments afforded by the two heteropolyanions. The relative importance of saturative coordination versus electrostatic stabilization in the redox behavior of these two complexes is discussed.

References

1. S. G. Bratsch, J. Phys. Chem. Ref. Data, 1989, 18, 1.
2. A. W. Maverick and Q. Yao, Inorg. Chem., 1993, 32, 5626.
3. D. E. Hobart, K. Samhoun, J. P. Young, V. E. Norvell, G. Mamantov and J. R. Peterson, Inorg. Nucl. Chem. Lett., 1980, 16, 321.
4. D. W. Wester, G. J. Palenik and R. C. Palenik, Inorg. Chem., 1985, 24, 4435.
5. R. D. Peacock and T. J. R. Weakley, J. Chem. Soc. A, 1971, 1836.
6. L. McKean and M. T. Pope, Inorg. Chem., 1974, 13, 747.
7. J. P. Ciabrini and R. Contant, J. Chem. Res. (S), 1993, 391.
8. I. Creaser, M. C. Heckel, R. J. Neitz and M. T. Pope, Inorg. Chem., 1993, 32, 1573.
9. N. Haraguchi, Y. Okaue, T. Isobe and Y. Matsuda, Inorg. Chem., 1994, 33, 1015.
10. T. Isobe and Y. Okaue, in New Development of Studies on Rare Earth Complexes, ed. G. Adachi, T. Yamase, J. Inanaga, M. Komiyama and K. Machida, The Rare Earth Society of Japan, Osaka, Japan, 1997, pp. 67–74.
11. M. R. Antonio and L. Soderholm, J. Cluster Sci., 1996, 7, 585.
12. M. R. Antonio, C. W. Williams and L. Soderholm, J. Alloys Compd., 1998, 271–273, 846.
13. M. T. Pope, Heteropoly and Isopoly Oxometalates, Springer-Verlag, Berlin, 1983.
14. M. T. Pope, in Comprehensive Coordination Chemistry, ed. G. Wilkinson, R. D. Gillard and J. A. McCleverty, Pergamon Press, New York, 1987, vol. 3, pp. 1023–1058.
15. M. T. Pope and A. Müller, Angew. Chem., Int. Ed. Engl., 1991, 30, 34.
16. M. T. Pope and A. Müller, Polyoxometalates: From Platonic Solids to Anti-Retroviral Activity, Kluwer, Dordrecht, 1994.
17. M. R. Antonio and L. Soderholm, J. Alloys Compd., 1997, 250, 541.
18. M. R. Antonio, L. Soderholm, L. C. Francesconi, M. Dankova and J. Bartis, J. Alloys Compd., 1998, 275–277, 827.
19. D. D. Dexter and J. V. Silverton, J. Am. Chem. Soc., 1968, 90, 3589.
20. J. Iball, J. N. Low and T. J. R. Weakley, J. Chem. Soc., Dalton Trans., 1974, 2021.
21. V. I. Spitsyn, M. M. Orlova, N. N. Krot and A. S. Saprykin, Russ. J. Inorg. Chem. (Transl. of Zh. Neorg. Khim.), 1978, 23, 677.
22. V. N. Molchanov, L. P. Kazanskii, E. A. Torchenkova and V. I. Simonov, Sov. Phys. Crystallogr. (Engl. Transl.), 1979, 24, 96.
23. K. Nomiya, H. Murasaki and M. Miwa, Polyhedron, 1985, 4, 1793.
24. W. H. Knoth, P. J. Domaille and R. L. Harlow, Inorg. Chem., 1986, 25, 1577.
25. M. R. Antonio and L. Soderholm, Inorg. Chem., 1994, 33, 5988.
26. L. G. Maksimova, T. A. Denisova, L. V. Kristallov, V. G. Kharchuk, N. A. Zhuravlev, V. L. Volkov and L. A. Petrov, Russ. J. Inorg. Chem. (Transl. of Zh. Neorg. Khim.), 1995, 40, 941.
27. M. T. Pope, X. Wei, K. Wassermann and M. H. Dickman, C. R. Acad. Sci., Ser. IIc: Chim., 1998, 1, 297.
28. C. Rosu and T. J. R. Weakley, Acta Crystallogr., Sect. C, 1998, 54 CIF-access paper IUC9800047.
29. J. Bartis, M. Dankova, M. Blumenstein and L. C. Francesconi, J. Alloys Compd., 1997, 249, 56.
30. J. Bartis, S. Sukal, M. Dankova, E. Kraft, R. Kronzon, M. Blumenstein and L. C. Francesconi, J. Chem. Soc., Dalton Trans., 1997, 1937.
31. M. T. Pope, in Mixed-Valence Compounds. Theory, and Applications in Chemistry, Physics, Geology, and Biology, ed. D. B. Brown, D. Reidel, Dordrecht, 1980, pp. 365–386.
32. L. Y. Qu, S. G. Wang, J. Peng, Y. G. Chen and G. Wang, Polyhedron, 1992, 11, 2645.
33. L. Y. Qu, S. G. Wang, J. Peng, Y. G. Chen and M. Yu, Chin. Sci. Bull., 1993, 38, 1087.
34. X. Xi, G. Wang, B. Liu and S. Dong, Electrochim. Acta, 1995, 40, 1025.
35. L. Soderholm, G. K. Liu, J. Muntean, J. Malinsky and M. R. Antonio, J. Phys. Chem., 1995, 99, 9611.
36. N. M. Edelstein, P. G. Allen, J. J. Bucher, D. K. Shuh, C. D. Sofield, N. Kaltsoyannis, G. H. Maunder, M. R. Russo and A. Sella, J. Am. Chem. Soc., 1996, 118, 13115.
37. J. S. Xue, M. R. Antonio, W. T. White, L. Soderholm and S. M. Kauzlarich, J. Alloys Compd., 1994, 207–208, 161.
38. R. Villanneau, A. Proust, F. Robert and P. Gouzerh, J. Chem. Soc., Dalton Trans., 1999, 421.
39. M. R. Antonio, U. Staub, J. S. Xue and L. Soderholm, Chem. Mater., 1996, 8, 2673.
40. G. Bidoglio, P. N. Gibson, E. Haltier, N. Omenetto and M. Lipponen, Radiochim. Acta, 1992, 58–59, 191.
41. C. Prieto, P. Lagarde, H. Dexpert, V. Briois, F. Villain and M. Verdaguer, J. Phys. Chem. Solids, 1992, 53, 233.
42. T. K. Sham, Phys. Rev. B: Condens. Matter, 1989, 40, 6045.
43. T. K. Sham, J. Chem. Phys., 1983, 79, 1116.
44. J. G. Darab, H. Li and J. D. Vienna, J. Non-Cryst. Solids, 1998, 226, 162.
45. S.-L. Lin, C.-S. Hwang and J.-F. Lee, J. Mater. Res., 1996, 11, 2641.
46. S. Skanthakumar and L. Soderholm, Phys. Rev. B: Condens. Matter, 1996, 53, 920.
47. R. F. Reidy and K. E. Swider, J. Am. Ceram. Soc., 1995, 78, 1121.
48. J. E. Sunstrom, S. M. Kauzlarich and M. R. Antonio, Chem. Mater., 1993, 5, 182.
49. S. H. Overbury, D. R. Huntley, D. R. Mullins and G. N. Glavee, Catal. Lett., 1998, 51, 133.
50. D. D. Beck, T. W. Capehart and R. W. Hoffman, Chem. Phys. Lett., 1989, 159, 207.
51. M. R. Antonio, J. F. Brazdil, L. C. Glaeser, M. Mehicic and R. G. Teller, J. Phys. Chem., 1988, 92, 2338.
52. A. J. Davenport, H. S. Isaacs and M. W. Kendig, Proc. – Electrochem. Soc., 1991, 91(7), 433.
53. A. J. Davenport, H. S. Isaacs and M. W. Kendig, Corros. Sci., 1991, 32, 653.
54. M. H. Dickman, G. J. Gama, K. C. Kim and M. T. Pope, J. Cluster Sci., 1996, 7, 567.
55. A. B. Yusov and V. P. Shilov, Radiochemistry (New York), 1999, 41, 1.
56. M. R. Antonio, L. Soderholm and I. Song, J. Appl. Electrochem., 1997, 27, 784.
57. F. W. Lytle, R. B. Greegor, D. R. Sandstrom, E. C. Marques, J. Wong, C. L. Spiro, G. P. Huffman and F. E. Huggins, Nucl. Instrum. Methods Phys. Res., Sect. A, 1984, 226, 542.
58. F. W. Lytle, in Applications of Synchrotron Radiation, ed. H. Winick, D. Xian, M. H. Ye and T. Huang, Gordon and Breach, New York, 1989, vol. 4, pp. 135–223.
59. G. N. George and I. J. Pickering, “EXAFSPAK: A Suite of Computer Programs for Analysis of X-ray Absorption Spectra,”http://www-ssrl.slac.stanford.edu/exafspak.html.
60. J. M. de Leon, J. J. Rehr, S. I. Zabinsky and R. C. Albers, Phys. Rev. B: Condens. Matter, 1991, 44, 4146.
61. J. J. Rehr, J. M. de Leon, S. I. Zabinsky and R. C. Albers, J. Am. Chem. Soc., 1991, 113, 5135.
62. A. W. Bott, Curr. Sep., 1995, 14, 64.
63. R. D. Shannon, Acta Crystallogr., Sect. A, 1976, 32, 751.
64. T. Gressling and H. Müller-Buschbaum, Z. Naturforsch., Teil B, 1995, 50, 1513.
65. M. H. Alizadeh, S. P. Harmalker, Y. Jeannin, J. M. Frere and M. T. Pope, J. Am. Chem. Soc., 1985, 107, 2662.
66. A. Wold and R. Ward, J. Am. Chem. Soc., 1954, 76, 1029.
67. M. R. Antonio, J. Malinsky and L. Soderholm, Mater. Res. Soc. Symp. Proc., 1995, 368, 223.
68. L. P. Kazansky and M. A. Fedotov, J. Chem. Soc., Chem. Commun., 1983, 417.