Nitrogen versus oxygen co-ordination of carboxamide-functionalized triazacyclononane ligands in transition metal ion complexes

Abstract

Mononuclear complexes of zinc(II), copper(II), nickel(II), cobalt(II), iron(II), manganese(II), chromium(III), vanadium(III) and vanadyl(IV) with the ligands 1,4,7-tris(carbamoylmethyl)-1,4,7-triazacyclonanone (L) and its N-methyl derivative C₆H₁₂N₃(CH₂CONHMe)₃ (MeL) have been prepared and structurally, magnetochemically and spectroscopically characterized. The ligands on complexation provide, in general, the MN₃O₃ moiety, i.e. they co-ordinate through the carboxamide oxygens with the exception of chromium(III). Chromium(III) forms complexes not only with the carboxamide oxygens, but also with the deprotonated amide nitrogen, thus yielding both CrN₃O₃ and CrN₄O₂ chromophores, respectively, which have been confirmed by crystal structures. The crystal structure of the VO²⁺ complex reveals a typical six-co-ordinate geometry with one amide dangling free, while that of the vanadium(III) compound shows seven-co-ordinate pentagonal bipyramidal geometry with the amide co-ordinated to the metal via its carbonyl oxygen atoms together with a chloride ion. The pendant carboxamide groups hydrolyse slowly to the corresponding carboxylic acid groups. The ligands L and MeL provide weak ligand fields and, relative to the trimethyl substituted cyclic amine [9]aneN₃, i.e. 1,4,7-trimethyl-1,4,7-triazacyclononane, are more effective in stabilizing the metal centers in the oxidation state II.

References

1. P. Chaudhuri and K. Wieghardt, Prog. Inorg. Chem., 1987, 35, 329.
2. See, for example, D. Burdinski, F. Birkelbach, T. Weyhermüller, U. Flörke, H.-J. Haupt, M. Lengen, A. X. Trautwein, E. Bill, K. Wieghardt and P. Chaudhuri, Inorg. Chem., 1998, 37, 1009; F. Birkelbach, U. Flörke, H.-J. Haupt, C. Butzlaff, A. X. Trautwein, K. Wieghardt and P. Chaudhuri, Inorg. Chem., 1998, 37, 2000.
3. K. P. Wainwright, Coord. Chem. Rev., 1997, 166, 35.
4. T. A. Kaden, Top. Curr. Chem., 1984, 121, 154.
5. P. V. Bernhardt and G. A. Lawrence, Coord. Chem. Rev., 1990, 104, 297.
6. M. Takahasi and S. Takamoto, Bull. Chem. Soc. Jpn., 1977, 50, 3413.
7. K. Wieghardt, U. Bossek, P. Chaudhuri, W. Herrmann, B. C. Menke and J. Weiss, Inorg. Chem., 1982, 21, 4308.
8. B. A. Sayer, J. P. Michael and R. D. Hancock, Inorg. Chim. Acta, 1983, 77, L63.
9. D. A. Moore, P. E. Fanwick and M. J. Welch, Inorg. Chem., 1989, 28, 1504.
10. T. Beissel, K. S. Bürger, G. Voigt, K. Wieghardt, C. Butzlaff and A. X. Trautwein, Inorg. Chem., 1993, 32, 124.
11. O. Schlager, K. Wieghardt, H. Grondey, A. Rufinska and B. Nuber, Inorg. Chem., 1995, 34, 6440.
12. L. R. Gahan, G. A. Lawrence and A. M. Sargeson, Aust. J. Chem., 1982, 35, 1119.
13. L. Christiansen, D. N. Hendrickson, H. Toflund, S. R. Wilson and C. L. Xie, Inorg. Chem., 1986, 25, 2813.
14. K. Wieghardt, E. Schöffmann, B. Nuber and J. Weiss, Inorg. Chem., 1986, 25, 4877.
15. R. Ziessel and J.-M. Lehn, Helv. Chim. Acta, 1990, 73, 1149.
16. M. Di Vaira, F. Manni and P. Stoppioni, J. Chem. Soc., Chem. Commun., 1989, 126.
17. M. Di Vaira, B. Cosimelli, F. Manni and P. Stoppioni, J. Chem. Soc., Dalton Trans., 1991, 331.
18. A. A. Watson, A. C. Willis and D. P. Fairlie, Inorg. Chem., 1997, 36, 752.
19. P. Chaudhuri and M. Winter, unpublished work; F. Birkelbach, Dissertation, Bochum, 1995.
20. H. Sigel and R. B. Martin, Chem. Rev., 1982, 82, 385.
21. J. K. Moran and C. F. Meares, in Encyclopedia of Inorganic Chemistry, ed. R. B. King, Wiley, New York, 1994, vol. 6, p. 3067.
22. (a) S. Amin, C. Marks, L. M. Toomey, M. R. Churchill and J. R. Morrow, Inorg. Chim. Acta, 1996, 246, 99; (b) L. M. Berreau, J. A. Halfen, V. G. Young and W. B. Tolman, Inorg. Chem., 1998, 37, 1091.
23. K. Wieghardt, W. Schmidt, B. Nuber and J. Weiss, Chem. Ber., 1979, 112, 2220.
24. T. J. Atkins, J. E. Richman and W. F. Oettle, Org. Synth., 1978, 58, 86.
25. W. E. Weaver and W. M. Whaley, J. Am. Chem. Soc., 1947, 69, 515.
26. R. Kataky, K. E. Matthes, P. E. Nicholson, D. Parker and H.-J. Buschmann, J. Chem. Soc., Perkin Trans. 2, 1990, 1425.
27. G. M. Sheldrick, SADBAS, University of Göttingen, 1994.
28. G. M. Sheldrick, SHELXTL PLUS, Siemens Analytical Instruments, Madison, WI, 1990.
29. (a) International Tables for X-Ray Crystallography, Kynoch Press, Birmingham, 1974, vol. 4; (b) H. D. Flack, Acta Crystallogr., Sect. A, 1983, 39, 876.
30. C. J. Ballhausen and H. B. Gray, Inorg. Chem., 1962, 1, 111.
31. A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier, Amsterdam, 1984.
32. C. K. Johnson, ORTEP, Report ORNL-5138, Oak Ridge National Laboratory, Oak Ridge, TN, 1976.
33. M. G. B. Drew, Prog. Inorg. Chem., 1977, 23, 67 and refs. therein.
34. R. A. Levenson and R. L. R. Townsend, Inorg. Chem., 1974, 13, 105.
35. M. Shimoi, Y. Saito and H. Ogino, Bull. Chem. Soc. Jpn., 1991, 64, 2629.
36. A. Neves, W. Walz, K. Wieghardt, B. Nuber and J. Weiss, Inorg. Chem., 1988, 27, 2484 and refs. therein J. C. Dutton, G. D. Fallon and K. S. Murray, Inorg. Chem., 1988, 27, 34; A. D. Keramidas, A. B. Papaiaanou, A. Vlahos, T. A. Kabanos, G. Bonas, A. Makriyannis, C. P. Rapropoulou and A. Terzis, Inorg. Chem., 1996, 35, 357 and refs. therein.
37. T. J. Collins, B. D. Santarsiero and G. H. Spies, J. Chem. Soc., Chem. Commun., 1983, 681.
38. C. M. Murdoch, M. K. Cooper, T. W. Hambley, W. N. Hunter and H. C. Freeman, J. Chem. Soc., Chem. Commun., 1986, 1329.
39. H. C. Freeman, Adv. Protein Chem., 1967, 22, 257.
40. O. Schlager, K. Wieghardt and B. Nuber, Inorg. Chem., 1995, 34, 6449.
41. M. J. van der Merwe, J. C. A. Boeyens and R. D. Hancock, Inorg. Chem., 1985, 24, 1208.
42. J. N. McElearney, R. W. Schwartz, A. E. Sieigel and R. L. Carlin, J. Am. Chem. Soc., 1971, 93, 4337; R. L. Carlin, C. J. O'Connor and S. N. Bhatia, Inorg. Chem., 1976, 15, 985; A. K. Gregson, D. M. Doddrell and P. C. Healy, Inorg. Chem., 1978, 17, 1216.
43. J. N. McElearney, R. W. Schwartz, S. Merchant and R. L. Carlin, J. Chem. Phys., 1971, 55, 466.
44. H. U. Rahman, J. Phys. C., 1971, 4, 3301.
45. Theory and Applications of Molecular Paramagnetism, eds. E. A. Boudreaux and L. N. Mulay, Wiley, New York, 1976.
46. Electron Paramagnetic Resonance of d Transition Metal Compounds, eds. F. E. Mabbs and D. Collison, Elsevier, Amsterdam, 1992.