Tetrakis(μ-anthracene-9-carboxylato)-κ4O:O′;κ3O,O′:O′;κ3O:O,O′-bis[(anthracene-9-carboxylato-κ2O,O′)(1,10-phenanthroline-κ2N,N′)erbium(III)]: effects of a noncoordinating anthracene ligand ring system on the final structure of a coordination complex

The title complex, [Er(2)(C(15)H(9)O(2))(6)(C(12)H(8)N(2))(2)], has a centrosymmetric binuclear cage structure in which the two Er(III) atoms are both nine-coordinated and are bridged by four bulky anthracene-9-carboxylate (L) ligands, with a nonbonding Er...Er separation of 3.9041 (2) A. The L groups coordinate each Er(III) atom in three different ways. The results reported here reveal that the bulky anthracene skeleton of the L ligand plays an important role in the formation of the complex by virtue of intra- and intermolecular pi-pi stacking and C-H...pi interactions.