Synthesis, structure and magnetic properties of a series of cubane-like clusters derived from Schiff base ligands

One new hexanuclear Cu(II) complex [Cu4(L1)4Na2(ClO4)(H2O)](ClO4)(H2O)0.5 (1) and two new tetranuclear Ni(II) complexes [Ni4(L2)4(CH3OH)4] (2), [Ni4(o-vanillinate)4(μ3-N3)4(CH3OH)4] (3) have been synthesized and structurally characterized. All the three complexes 1, 2, and 3 have been characterized by elemental analysis, FTIR, and single crystal X-ray diffraction studies. Single crystal X-ray diffraction studies reveal that all three complexes consist of a cubane core in which the four Cu(II)/Ni(II) centers in 1 and 2 are linked by μ3-alkoxo bridges and Ni(II) ions in 3 are linked by azido bridge in end-on fashion. The skeleton structures of the cubane cores are all distorted from the idealized cube and most show a further distortion. The variable-temperature (2–300 K) magnetic susceptibilities and magnetizations of the three compounds were measured. Variable-temperature magnetic susceptibility data exhibit dominant antiferromagnetic interaction in complex 1 while ferromagnetic interactions in complexes 2 and 3.

Graphical abstractThree cubane-type complexes have been synthesized by a minor modification of the Schiff base ligands and the type of bases. Based upon the structural features within the cubane core, the magneto-structural correlations of the three compounds were successfully analyzed.Figure optionsDownload full-size imageDownload as PowerPoint slide