Metal–Ligand Ratio Controlled Assembly Of Two Heterometallic CuEr Cluster Complexes: Syntheses, Structures and Magnetism

Abstract

Two new heterometallic CuEr cluster complexes based on 3,5-dichlorobenzoic acid (HL) and 2,2′:6′,2″-terpyridine (TPY), [Cu(L)(TPY)][Er(L)4]·H2O (1) and [Cu(L)(TPY)][Er2(L)7] (2), have been hydrothermally prepared by controlling the metal–ligand ratios. Comparative study revealed that metal–ligand ratios affected the coordination modes of L− and thus generate two distinct structures. Both complexes display as ion-pair bicomponent structures. The cationic [Cu(L)(TPY)]+ components show the similar binuclear cluster structure in two complexes, while the two anionic parts are very different. In 1, two Er(III) centers are coordinated by four bridging and four chelating L− ligands to form the binuclear anionic [Er2(L)8]2− cluster. While in 2, all L− ligands show the bridging modes and connect the Er(III) centers into an extended one-dimensional (1D) chain. So the overall structures of 1 and 2 are bicomponent 0D + 0D and 0D + 1D structures, respectively. Direct current magnetic susceptibility measurements were performed for two complexes and they both showed antiferromagnetic behavior.