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

Three copper(II) complexes namely [Cu4(L¹)4]·0.5(H2O) (1), [Cu4(L²)2(HL²)2(H2O)2](sq)·H2O (2) and {[Cu2(L²)2(tp)]·(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…π interactions among the 1D polymeric chains form a 2D supramolecular architecture. Variable temperature magnetic property study indicates overall antiferromagnetic exchange coupling in all complexes.