Syntheses, crystal structures and magnetic properties of [Ni₂(C₂O₄)(tren)₂][ClO ₄]₂ and [Ni₂(C₄O₄)(tren)₂(H₂ O)₂][ClO₄]₂ [tren = tris(2-aminoethyl)amine]

Abstract

Two dinuclear nickel(II) complexes [Ni₂(C₂O₄)(tren)₂][ClO ₄]₂1 and [Ni₂(C₄O₄)(tren)₂(H₂ O)₂][ClO₄]₂2 [tren = tris(2-aminoethyl)amine, C₂O₄^2- = oxalate dianion and C₄O₄^2- = dianion of 3,4-dihydroxycyclobut-3-en-1,2-dione (squaric acid)] have been synthesized and characterized by single-crystal X-ray diffraction. Their structures consist of dinuclear nickel(II) cations and unco-ordinated perchlorate anions. The nickel environment is distorted octahedral NiN₄O₂ in both complexes: four nitrogen atoms of the tren group acting as a tetradentate ligand and two oxygen atoms of oxalate (1) or a water molecule and a squarate oxygen (2) comprise the co-ordination. The oxalate acts as a bis(chelating) ligand whereas the squarate adopts a µ-1,2-bis(monodentate) co-ordination mode. The intradimer metal–metal separation is 5.413(1) and 6.224(1) Å in 1 and 2, respectively. The co-ordinated water molecule in 2 forms an intramolecular hydrogen bond to an unco-ordinated squarate-oxygen atom. Variable-temperature susceptibility measurements revealed the occurrence of relatively strong (1) and weak (2) intramolecular antiferromagnetic coupling, the relevant parameters being J = -28.8 cm^-1 and g = 2.16 for 1 and J = -0.4 cm^-1 and g = 2.15 for 2 (J being the exchange parameter in the isotropic spin Hamiltonian H̄ = -JS̄_A·S̄_B). A comparative study of the ability of oxalate and squarate groups to mediate electronic interactions in the structurally characterized oxalato- and squarato-bridged nickel(II) complexes was carried out.

References

1. M. Verdaguer, M. Julve, A. Michalowicz and O. Kahn, Inorg. Chem., 1983, 22, 2624.
2. M. Habenschuss and B. C. Gerstein, Chem. Phys., 1974, 61, 852.
3. X. Solans, M. Aguiló, A. Gleizes, J. Faus, M. Julve and M. Verdaguer, Inorg. Chem., 1990, 29, 775.
4. D. L. Kepert, in Inorganic Stereochemistry, eds. C. K. Jørgensen, M. F. Lappert, S. J. Lippard, J. L. Margrave, K. Niedenzu, H. North, R. W. Parry and H. Yamatera, Springer, Berlin, 1982, vol. 6.
5. C. Robl and A. Weiss, Z. Naturforsch., Teil B, 1986, 41, 1490; C. Robl, V. Gnutzmann and A. Weiss, Z. Anorg. Allg. Chem., 1987, 549, 187; C. Robl and A. Weiss, Mater. Res. Bull., 1987, 22, 373.
6. J. C. Trombe, J. F. Petit and A. Gleizes, New J. Chem., 1988, 12, 197; Inorg. Chim. Acta, 1990, 167, 69; Eur. J. Solid State Inorg. Chem., 1991, 28, 669.
7. D. Coucouvanis, F. J. Hollander, R. West and D. Eggerding, J. Am. Chem. Soc., 1974, 96, 3006; D. Coucouvanis, D. G. Holah and F. J. Hollander, Inorg. Chem., 1975, 14, 2657.
8. M. L. Calatayud, I. Castro, J. Sletten, J. Cano, F. Lloret, J. Faus, M. Julve, G. Seitz and K. Mann, Inorg. Chem., 1996, 35, 2858.
9. R. Grenz, F. Götzfreid, U. Nagel and W. Beck, Chem. Ber., 1986, 119, 1217.
10. (a) P. W. Ball and A. B. Blake, J. Chem. Soc., 1969, 1415; (b) D. M. Duggan, E. K. Barefield and D. N. Hendrickson, Inorg. Chem., 1973, 12, 985; (c) V. V. Zelentsov, L. M. Chanturiya and N. I. Pitskhalava, Koord. Khim., 1978, 4, 764; (d) J. Ribas, M. Monfort, C. Díaz and X. Solans, An. Quím., 1988, 84, 186; (e) L. P. Battaglia, A. Bianchi, A. Bonamartini Corradi, E. García-España, M. Micheloni and M. Julve, Inorg. Chem., 1988, 27, 4174; (f) A. Bencini, A. Bianchi, P. Paoli, E. García-España, Y. Jeannin, M. Julve, V. Marcelino and M. Philoche-Levisalles, Inorg. Chem., 1990, 29, 963; (g) A. Bencini, A. Bianchi, P. Paoli, E. García-España, M. Julve and V. Marcelino, J. Chem. Soc., Dalton Trans., 1990, 2213; (h) K. Yamada, Y. Fukuda, T. Kawamato, Y. Kushi, W. Mori and K. Unuora, Bull. Chem. Soc. Jpn., 1993, 66, 2758; (i) A. Escuer, R. Vicente, J. Ribas, J. Jaud and B. Raynaud, Inorg. Chim. Acta, 1994, 216, 139; (j) A. Escuer, R. Vicente, M. Sallah El Fallah and J. Jaud, Inorg. Chim. Acta, 1995, 232, 151; (k) P. Román, C. Guzmán-Miralles, A. Luque, J. I. Beitia, J. Cano, F. Lloret, M. Julve and S. Alvarez, Inorg. Chem., 1996, 35, 3741.
11. J. A. C. van Ooijen, J. Reedijk and A. L. Spek, Inorg. Chem., 1979, 18, 1184.
12. R. Soules, F. Dahan, J. P. Laurent and P. Castan, J. Chem. Soc., Dalton Trans., 1988, 587.
13. A. Earnshaw, Introduction to Magnetochemistry, Academic Press, London, New York, 1968.
14. P. Main, S. J. Fiske, S. E. Hull, L. Lessinger, G. Germain, J. P. DeClercq and W. W. Woolfson, MULTAN 80, A System of Computer Programs for the Automatic Solution of Crystal Structures from X-Ray Diffraction Data, University of York, 1980.
15. C. K. Fair, MOLEN, An Interactive Structure Solution Procedure, Enraf-Nonius, Delft, 1990.
16. D. T. Cromer and J. T. Waber, International Tables for X-Ray Crystallography, Kynoch Press, Birmingham, 1974, vol. 4, Table 2.2.B; D. T. Cromer and J. B. Mann, Acta Crystallogr., Sect. A, 1968, 24, 321.
17. D. T. Cromer, International Tables for X-Ray Crystallography, Kynoch Press, Birmingham, 1974, vol. 4, Table 2.3.1.
18. (a) P. D. Cradwick and D. Hall, Acta Crystallogr., Sect. B, 1970, 26, 1384; (b) D. M. Duggan and D. N. Hendrickson, Inorg. Chem., 1974, 13, 2056; (c) C. G. Pierpont, D. N. Hendrickson, D. M. Duggan, F. Wagner and E. K. Barefield, Inorg. Chem., 1975, 14, 604; (d) B. C. Segal and S. J. Lippard, Inorg. Chem., 1977, 16, 1623; (e) C. G. Pierpont, L. C. Francesconi and D. N. Hendrickson, Inorg Chem., 1977, 16, 1977.
19. D. Semmingsen, Acta Chem. Scand., 1973, 27, 3961.
20. M. Ito and B. West, J. Am. Chem. Soc., 1963, 85, 2580.
21. G. De Munno, M. Julve, F. Lloret and A. Derory, J. Chem. Soc., Dalton Trans., 1993, 1179.
22. A. P. Ginsberg, R. L. Martin, R. W. Brookes and R. C. Sherwood, Inorg. Chem., 1972, 11, 2884.
23. C. E. Xanthopoulos, M. P. Sigalas, G. A. Katsoulos, C. A. Tsipis, C. C. Hadjikostas, A. Terzis and M. Mentzafos, Inorg. Chem., 1993, 32, 3743.
24. O. Kahn, Struct. Bonding (Berlin), 1987, 68, 89 and refs. therein.
25. I. Castro, J. Sletten, M. L. Calatayud, M. Julve, J. Cano, F. Lloret and A. Caneschi, Inorg. Chem., 1995, 34, 4903.
26. O. Kahn and M. F. Charlot, Nouv. J. Chim., 1980, 4, 567.