New dioxocyclam ligands appended with 2-pyridylmethyl pendant(s): synthesis, properties and crystal structure of their copper(II) complexes (dioxocyclam = 1,4,8,11-tetraazacyclotetradecane-12,14-dione) ‡

Abstract

Two new dioxocyclam ligands, 4-(pyridin-2-ylmethyl)-1,4,8,11-tetraazacyclotetradecane-12,14-dione (L¹) and 4,8-bis(pyridin-2-ylmethyl)-1,4,8,11-tetraazacyclotetradecane-12,14-dione (L²), have been synthesized and characterized. The solution chemistry of the Cu^II complexes with these ligands have been studied by potentiometric and spectroscopic titration, cyclic voltammetry (CV), UV/VIS and ESR spectral techniques. The Cu^II complex of L² has been isolated as single crystals and the structure has been determined by X-ray diffraction analysis to be [CuL²][ClO₄]₂ 1. In complex 1, the Cu^II atom is five-co-ordinate with the two pendant pyridyl nitrogens and the two tertiary amines forming a distorted trigonal-bipyramidal configuration in which the backbone oxygen O(2) co-ordinates to Cu^II while the two amido nitrogen groups remained non-deprotonated and non-co-ordinated. To our knowledge, this is the first example of Cu^II complexes of dioxotetraamines in which the backbone oxygen co-ordinates to the central metal by twisting the backbone.

References

1. (a) E. Kimura, J. Coord. Chem., 1986, 15, 1; (b) E. Kimura, Pure Appl. Chem., 1986, 58, 1461; (c) E. Kimura, Crown Compounds Toward Future Applications, ed. S. R. Cooper, VCH, New York, 1992, ch. 6.
2. (a) M. Kodama and E. Kimura, J. Chem. Soc., Dalton Trans., 1979, 325; (b) M. Kodama and E. Kimura, ibid., 1979, 1783; (c) M. Kodama and E. Kimura, ibid., 1981, 694; (d) K. Ishizu, J. Hirai, M. Kodama and E. Kimura, Chem. Lett., 1979, 1045; (e) R. Machida, E. Kimura and M. Kodama, Inorg. Chem., 1983, 22, 2055; (f) E. Kimura, T. Koike, R. Machida, R. Nagai and M. Kodama, Inorg. Chem., 1984, 23, 4181; (g) E. Kimura, C. A. Dalimunte, A. Yamashita and R. Machida, J. Chem. Soc., Chem. Commun., 1985, 1041; (h) E. Kimura, Y. Lin, R. Machida and H. Zenda, ibid., 1986, 1020; (i) E. Kimura, S. Korenari, M. Shionoya and M. Shiro, ibid., 1988, 1166; (j) E. Kimura, M. Shionoya, M. Okamoto and H. Nada, J. Am. Chem. Soc., 1988, 110, 3679; (k) M. Shionoya, E. Kimura and Y. Iitaka, ibid., 1990, 112, 9237.
3. R. W. Hay, M. P. Pujari and F. McLaren, Inorg. Chem., 1984, 23, 3033; L. Fabbrizzi, Inorg. Chem., 1985, 4, 33; L. C. Siegfried and T. A. Kaden, J. Phys. Org. Chem., 1992, 549; L. Fabbrizzi, A. Perotti, A. Profumo and T. Soldi, Inorg. Chem., 1986, 25, 4256; L. Fabbrizzi, F. Forlini, A. Perotti and B. Seghi, Inorg. Chem., 1984, 23, 807; L. Fabbrizzi, T. A. Kaden, A. Perotti, B. Seghi and L. Seigfried, Inorg. Chem., 1986, 25, 321; G. D. Santis, L. Fabbrizzi, M. Licchelli and P. Pallavicini, Coord. Chem. Rev., 1992, 120, 237.
4. E. Kimura and H. Nada, Tanpakushitsu Kakusan Koso, 1988, 16, 2914; R. Machida, E. Kimura and M. Kodama, Inorg. Chem., 1983, 22, 2055; E. Kimura and R. Machida, Yuki Gosei Kagaku Kyokaishi, 1984, 42, 407.
5. B. J. Hathaway, in Comprehensive Coordination Chemistry, ed. G. Wilkinson, Pergamon Press, Oxford, 1987, 5, p. 533.
6. X. H. Bu, D. L. An, Y. T. Chen, M. Shionoya and E. Kimura, J. Chem. Soc., Dalton Trans., 1995, 2289; X. H. Bu, X. C. Cao, D. L. An, R. H. Zhang, T. Clifford and E. Kimura, ibid., 1998, 433.
7. L. Fabbrizzi and A. Poggi, J. Chem. Soc., Chem. Commun., 1980, 646; L. Fabbrizzi, A. Perotti and A. Poggi, Inorg. Chem., 1983, 22, 1411; L. Fabbrizzi, A. Perotti, A. Profumo and T. Soldi, Inorg. Chem., 1986, 25, 4256; R. Hay, R. Rembi and W. Sommerville, Inorg. Chim. Acta, 1982, 59, 147; Y. D. Lampeka and S. P. Gavrish, J. Coord. Chem., 1990, 21, 351.
8. D. W. Margerum and G. D. Oven, in Metal Ions in Biological Systems, ed. H. Sigel, Marcel Dekker, New York, 1981, vol. 12, p. 75; T. R. Wagner and C. J. Burrows, Tetrahedron Lett., 1988, 29, 5091; T. R. Wagner, Y. Fang and C. J. Burrows, J. Org. Chem., 1989, 54, 1584.
9. See, for example, E. Kimura, J. Inclusion Phenom., 1989, 7, 183; E. Kimura, Pure Appl. Chem., 1989, 61, 823; E. Kimura, Tetrahedron, 1992, 48, 6175; P. V. Bernhardt and G. A. Lawrence, Coord. Chem. Rev., 1990, 104, 297; T. A. Kaden, Crown Compounds Toward Future Applications, ed. S. R. Cooper, VCH, New York, 1992, ch. 8; E. Kimura, X. H. Bu, M. Shionoya, S. Wada and S. Maruyama, Inorg. Chem., 1992, 31, 4542; X. H. Bu, Y. T. Chen, M. Shionoya and E. Kimura, Polyhedron, 1994, 13, 325; E. Kimura, S. Wada, M. Shionoya and Y. Okazaki, Inorg. Chem., 1994, 33, 770.
10. E. Kimura, T. Koike, R. Machida, R. Nagai and M. Kodama, Inorg. Chem., 1984, 23, 4181; E. Kimura, T. Koike, H. Nada and Y. Iitaka, ibid., 1988, 27, 1036.
11. X. H. Bu, D. L. An, Y. T. Chen, M. Shionoya and E. Kimura, J. Inclusion Phenom., 1997, 27, 245.
12. I. Tabushi, H. Okino and Y. Kuroda, Tetrahedron Lett., 1976, 4339.
13. E. Kimura, T. Kioke, K. Uenishi, M. Hedigar, M. Kuramoto, S. Joko, M. Kodama and Y. Iitaka, Inorg. Chem., 1987, 26, 2975.
14. G. M. Sheldrick, SHELXTL PC, Siemens Analytical X-Ray Instruments, Inc., Madison, WI, 1990.
15. P. Gans, A. Sabatini and A. Vacca, Talanta, 1996, 43, 1739.
16. C. K. Johnson, ORTEP, Report ORNL-5138, Oak Ridge National Laboratory, Oak Ridge, TN, 1976.
17. K. Miyoshi, H. Tanaka, E. Kimura, S. Tsuboyama, S. Murata, H. Shimizu and K. Ishizu, Inorg. Chim. Acta, 1983, 78, 23.
18. A. S. Brill, Molecular Biology Biochemistry and Biophysics. 26. Transition Metals in Biochemistry, ed. A. Kleinzeller, Springer-Verlag, New York, 1977, p. 43.