Novel Luminescent Three-Dimensional Heterometallic Complexes with 2-Fold Interpenetrating (3,6)-Connected Nets

A series of novel three-dimensional (3D) 3d-4f heterometallic coordination complexes, [{LnZn(bpdc)2(OAc)(H2O)2}·H2O]n (Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5), Er (6); H2bpdc = 2,2′-bipyridyl-4,4′-dicarboxylic acid; HOAc = acetic acid), have been successfully synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. All complexes are isostructural and display new 2-fold interpenetrating (3,6)-connected network topology. The luminescent properties of 1–5 in the solid state at room temperature have been studied in detail. It is the first series of luminescent 3d-4f heterometallic complexes with bpdc2– ligands, and it has been found that the energy transitions from the ligands to Eu3+ and Tb3+ are more effective than those to Sm3+ and Nd3+, and the energy transition from the ligand to Dy3+ is in between. Furthermore, thermogravimetric analysis and powder X-ray diffraction are also investigated.