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

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 ]·H 2 O ( 1 ) and [Cu(L)(TPY)][Er 2 (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 [Er 2 (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.