Self-Assembly of Antiferromagnetically-Coupled Copper(II) Supramolecular Architectures with Diverse Structural Complexities.

ABSTRACT

The self-assembly of 2,6-diformyl-4-methylphenol (DFMP) and 1-amino-2-propanol (AP)/2-amino-1,3-propanediol (APD) in the presence of copper(II) ions results in the formation of six new supramolecular architectures containing two versatile double Schiff base ligands (H3L and H5L1) with one-, two-, or three-dimensional structures involving diverse nuclearities tetranuclear [Cu4(HL2-)2(N3)4]·4CH3OH·56H2O (1) and [Cu4(L3-)2(OH)2(H2O)2] (2), dinuclear [Cu2(H3L12-)(N3)(H2O)(NO3)] (3), polynuclear {[Cu2(H3L12-)(H2O)(BF4)(N3)]·H2O}n (4), heptanuclear [Cu7(H3L12-)2(O)2(C6H5CO2)6]·6CH3OH·44H2O (5), and decanuclear [Cu10(H3L12-)4(O)2(OH)2(C6H5CO2)4] (C6H5CO2)2·20H2O (6). X-ray studies have revealed that the basic building block in 1, 3, and 4 is comprised of two copper centers bridged through one µ-phenolate oxygen atom from HL2- or H3L12-, and one µ-1,1-azido (N3-) ion and in 2, 5, and 6 by µ-phenoxide oxygen of L3- or H3L12- and µ-O2- or µ3-O2- ions. H-bonding involving coordinated/uncoordinated hydroxy groups of the ligands generates fascinating supramolecular architectures with 1D-single chains (1 and 6), 2D-sheets (3), and 3D-structures (4). In 5, benzoate ions display four different coordination modes, which, in our opinion, is unprecedented and constitutes a new discovery. In 1, 3, and 5, Cu(II) ions in [Cu2] units are antiferromagnetically coupled, with J ranging from -177 to -278 cm-1.