Structure and magnetic characterization of tetranuclear closed/double-open cubane core, and 1D polynuclear copper(II) complexes

Three copper(II) complexes namely [Cu-4(L-1)(4)]center dot 0.5(H2O) (1), [Cu-4(L-2)(2)(HL2)(2)(H2O)(2)](sq)center dot H2O (2) and {[Cu-2(L-2)(2)(tp)]center dot(H2O)}(n) (3) (H2L1 = [(E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol], H2L2 = [(E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol] sq = squarate and tp = terephthalate ion) have been characterized by structure determination and magnetic analysis. Both 1 and 2 are tetranuclear Cu4O4 species with closed cubane core and double-open cubane like core structure, respectively. On the other hand complex 3 is a 1D polymeric chain, where Schiff base chelated dinuclear copper units are linked through terephthalate ions. C-H center dot center dot center dot pi interactions among the 1D polymeric chains form a 2D supramolecular architecture. Variable temperature magnetic property study indicates overall antiferromagnetic exchange coupling in all complexes.