The title complex was isolated as a red solid from the reaction of 4-(salicylaldiminato)antipyrine, HL, and cobalt (II) acetate in ethanol. The complex has been characterized by elemental analysis, FTIR, UV-Vis, and X-ray single crystal diffraction. Two crystallographically different cationic units, A and B, of the title complex are found. Both units are essentially isostructural; nevertheless, small differences exist between them. Both units contain four cobalt atoms arranged at the corners of distorted cubane-like core alternatively with phenoxy oxygen of the Schiff base. In both cases, one cobalt binds to three coordinated sites from the corresponding tridentate Schiff base ligand, and the fourth one was bonded by the acetate oxygen, and the fifth and the sixth donor sites come from the phenolate oxygen of another Schiff base ligand. 1. Introduction Polynuclear as well as binuclear Co(II) complexes have attracted much attention due to their potential advantages than mononuclear complexes toward the preparation of molecular magnets and their application in data storage and memory devices [1]. The discovery of single molecule magnetism (SMM) in high-spin Ni(II) molecular clusters, particularly in cubane-like tetranuclear Ni(II) complexes, revived the interest in such compounds in order to study the correlation between the magnetic anisotropy of the high-spin ground state and the magnetization at low temperatures [2]. In comparison to mononuclear complexes, binuclear and polynuclear complexes could also provide more than one metal active center as Lewis acid in catalytic process, which is the interest of many researchers [3]. Crystal structures of complexes containing Co4O4 cubane-like core, as Co4O4(OAc)2(bpy)4 (ClO4)2, Co4(CH3O)4(C5H7O2)4(C2H3O2) , and Co4O4(C8H9N2O2) 7.5H2O [4], are well-known for several decades. Polynuclear metal complexes with tridentate ligands containing at least one hydroxyl group and oxygen as terminal coordinating atom have been reported and attracted much attention [5]. These ligands often form polynuclear complexes with cubane or double cubane structure with missing one vertex each [6]. Antipyrine and its derivatives are one of such compounds that act as tridentate ligands, and this type of ligands has been attractive to researchers, since they are used as antifever and pain reliving drugs [7]. Transition metal Schiff base complexes have been also used as antifungal and antibacterial reagents [8]. It is shown that transition metal complexes containing 4-aminoantipyrine as a Schiff base have anticancer and antibacterial
References
[1]
E. K. Brechin, C. Boskovic, W. Wernsdorfer et al., “Quantum tunneling of magnetization in a new [Mn18]2+ single-molecule magnet with S = 13,” Journal of the American Chemical Society, vol. 124, no. 33, pp. 9710–9711, 2002.
[2]
M. Moragues-Cánovas, M. Helliwell, L. Ricard et al., “An Ni4 single-molecule magnet: synthesis, structure and low-temperature magnetic behavior,” European Journal of Inorganic Chemistry, vol. 2004, no. 11, pp. 2219–2222, 2004.
[3]
J. Wang, J. Wu, and N. Tang, “Synthesis, characterization of a new bicobalt complex [Co2L2(C2H5OH)2Cl2] and application in cyclic carbonate synthesis,” Inorganic Chemistry Communications, vol. 10, no. 12, pp. 1493–1495, 2007.
[4]
K. Dimitrov, K. Folting, W. E. Stereib, and G. Christo, “Dimerization of the [CoIII2(OH)2] core to the first example of a [CoIII4O4] cubane: potential insights into photosynthetic water oxidation,” Journal of the American Chemical Society, vol. 115, no. 14, pp. 6432–6433, 1993.
[5]
M. Koikawa, H. Yamashita, and T. Tokii, “Synthesis, structure, and characterization of dicopper(II) complex with a new amidate ligand,” Inorganic Chemistry Communications, vol. 6, no. 2, pp. 157–161, 2003.
[6]
A. E. Wasson and R. L. La Duca, “Hydrothermal synthesis, crystal structures, and properties of two 3-D network nickel nicotinate coordination polymers: [Ni4(μ-H2O)2(nicotinate)8· 2H2O] and [Ni2(H2O)2(nicotinate)4(4,4′-bpy)],” Polyhedron, vol. 26, no. 5, pp. 1001–1011, 2007.
[7]
O. Y. Neiland, Organic Chemistry, Vysshaya Shkola, Moscow, Russia, 1990 (Russian).
[8]
J. A. Ibers and R. H. Holm, “Modeling coordination sites in metallobiomolecules,” Science, vol. 209, no. 4453, pp. 223–235, 1980.
[9]
M. T. H. Tarafder, M. A. Ali, D. J. Wee, et al., “Complexes of a tridentate ONS Schiff base. Synthesis and biological properties,” Transition Metal Chemistry, vol. 25, no. 4, pp. 456–460, 2000.
[10]
A. Syamal and R. M. Maurya, “Oxidation of benzoin catalyzed by oxovanadium(iv) Schiff base,” Coordination Chemistry Reviews, vol. 18, p. 537, 1999.
[11]
G. T. P. Britorsck, V. C. Gibson, and D. F. Wass, “The search for new-generation olefin polymerization catalysts,” Angewandte Chemie—International Edition, vol. 38, p. 428, 1999.
[12]
Y. M. Chumakov, B. Y. Antosyak, M. D. Mazus, V. I. Taspkov, and M. N. Samus', “Crystal Structure of N-(salicylidene)-4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one,” Journal of Structural Chemistry, vol. 41, no. 5, pp. 905–909, 2000.
[13]
A. Altomare, G. Cascarano, C. Giacovazzo et al., “A program for automatic solution of crystal structures by direct methods,” Journal of Applied Crystallography, vol. 27, p. 435, 1994.
[14]
G. M. Sheldrick, “A short history of SHELX,” Acta Crystallographica A, vol. 64, part 1, pp. 112–122, 2008.
[15]
L. J. Farrugia, “WinGX suite for small-molecule single-crystal crystallography,” Journal of Applied Crystallography, vol. 32, pp. 837–838, 1999.
A. Altomare, M. C. Burla, M. Camalli et al., “SIR97: a new tool for crystal structure determination and refinement,” Journal of Applied Crystallography, vol. 32, no. 1, pp. 115–119, 1999.
[18]
L. J. Farrugia, ORTEP-3 for Windows, University of Glasgow, Glasgow, Scotland, 1997.
[19]
C. F. Macrae, P. R. Edgington, P. McCabe et al., “Mercury: visualization and analysis of crystal structures,” Journal of Applied Crystallography, vol. 39, no. 3, pp. 453–457, 2006.
[20]
S. P. Westrip, “publCIF: software for editing, validating and formatting crystallographic information files,” Journal of Applied Crystallography, vol. 43, no. 4, pp. 920–925, 2010.
[21]
M. Nardelli, “PARST95—an update to PARST: a system of Fortran routines for calculating molecular structure parameters from the results of crystal structure analyses,” Journal of Applied Crystallography, vol. 28, part 5, p. 659, 1995.
[22]
R. H. Wang, D.-Q. Yuan, F.-L. Jiang, L. Han, S. Gao, and M. C. Hong, “Syntheses, structures, and characterization of two manganese(II)-aminobenzoic complexes,” European Journal of Inorganic Chemistry, vol. 2006, no. 8, pp. 1649–1656, 2006.
[23]
L. Yaushiro, H. Nami, K. Hiroshi, and F. Shigenoba, “Electronic spectra of Co(II) Complexes,” Analytical Sciences, vol. 17, p. 187, 2001.
[24]
M. A. Halerow, J.-S. Sun, J. C. Huffman, and G. Christou, “Structural and magnetic properties of [Ni4(.mu.3-OMe)4(dbm)4(MeOH)4] and [Ni4(.eta.1,.mu.3-N3)4(dbm)4(EtOH)4]. Magnetostructural correlations for [Ni4X4]4+ cubane complexes,” Inorganic Chemistry, vol. 34, no. 16, pp. 4167–4177, 1995.
[25]
W. L. Gladfelter, M. W. Lynch, W. P. Schaefer, D. N. Henderikson, and H. B. Gray, “Synthesis, physical properties, and crystal structure of the cubane compound bis(.mu.-acetato)-tetra-.mu.-methoxo-bis[.mu.-(2,5-dimethyl-2,5-diisocyanohexane)]-tetranickel(II) tetraphenylborate,” Inorganic Chemistry, vol. 20, pp. 2390–2397, 1981.
[26]
X. Zhang, W. You, Z. Zhu, L. Dang, Z. Sun, and X. Zheng, “Hydrothermal synthesis and characterization of a novel crystal containing [Co4O4]4+ cubane core: [Co4O4(dpaH)4(CH3COO)2]2V4O12· 5H2O,” Inorganic Chemistry Communications, vol. 9, no. 5, pp. 526–528, 2006.
[27]
R. M. El-Mehdawi, N. A. Eldewik, K. M. Kreddan et al., “Synthesis and crystal structure of Bis-[Co (L)(NCS)(MeOH)] where (LH = 4-(Salicylaldiminato) antipyrine,” Jordan Journal of Chemistry, vol. 5, p. 157, 2010.
