A novel copper diphosphonate complex Cu4(aedp)2(4,4′-bpy)(H2O)4 with three-dimensional framework structure

A novel copper organodiphosphonate complex containing a second ligand 4,4'-bipyridine (4,4-bpy) based on 1-aminoethylidenediphosphonic acid (H(4)aedp), Cu-4(aedp)(2)(4,4-bpy)(H2O)(4) (1), has been synthesized under hydrothermal conditions. Complex 1 adopts a three-dimensional framework structure assembled from {Cu-4(aedp)(2)(H2O)(4)} layers and 4,4'-bpy bridges. Each {Cu-4(aedp)(2)(H2O)(4)} unit consists of three crystallographically distinct Cu atoms. The Cu(I) atom has a distorted square pyramidal geometry, whereas the Cu(2) and Cu(3) atoms have a distorted elongated tetragonal octahedral geometry. The magnetic studies indicate that complex I show typical antiferromagnetic behaviors at low temperature, which is attributed to the superexchange couplings between Cu(II) centers through mu-O bridge in the phosphonate layers. Crystal data for 1: triclinic, space group P (1) over bar, a = 8.0931(16), b = 13.567(3), c = 6.2185(12)angstrom, alpha = 90.55(3), beta = 96.97(3), gamma = 78.50(3)degrees, V = 664.1(2)angstrom(3), Z = 2. (C) 2005 Elsevier Inc. All rights reserved.