The crystal structures have been determined and the magnetic properties investigated for four novel] n 4 the combination of the metal cation with the dicarboxylate ligand leads to the formation of infinitive chains; still the co-ordinated water molecules and the carboxylate oxygen atoms collaborate to hydrogen-bond the chains into 3-D structures. Each cadmium() and nickel() ion in 1 and 4 is coordinated in an octahedral geometry to carboxylate and water molecules. The coordination sphere around copper() ions in 2 is square planar. The structure of 3, [Cu 3 (A) 2 (OH) 2 (H 2 O) 4 ] n , is made up of ribbons linked to neighboring ones by hydrogen bonds. Each ribbon is composed of 2 crystallographically independent metal centers, Cu(1) and Cu(2), which exhibit octahedral and square pyramidal coordination geometries, respectively. Weak antiferromagnetic interactions were observed for 2, and 3 (singlet-triplet energy gap values of Ϫ2.3 and Ϫ54.5 cm Ϫ1 , respectively) and isolated nickel() ions for 4. An interpretation of the magnetic behavior was attempted. The strategy for the assembly of 1-D metal-organic chains into 3-D structures, with the use of coordinated water molecules as hydrogen bond donors and carboxylate oxygens as hydrogen bond acceptors, is also discussed.

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