Assembly of a Secondary Building Unit (SBU) into Two- and Three-Dimensional Structures in Lanthanide Benzenedicarboxylates

Two series of lanthanide benzenedicarboxylates of the general framework formula [M 2 (2,2‘-bipy) 2 (C 8 H 4 O 4 ) 3 ] (M = Y, Gd, and Dy) have been prepared employing hydrothermal methods, and their structures were determined by single-crystal X-ray diffraction. Both the structure types contain only one type of secondary building units (SBU), which are connected differently giving rise to two- and three-dimensional (2- or 3-D) structures. While the 2-D structure is related to an augmented square lattice, the 3-D one closely resembles the CdSO 4 structure. This is the first observation, to our knowledge, of a CdSO 4 structure in the coordination polymers containing the rare earth ions. The formation of these structures has been rationalized from the connectivity between the building units, which clearly indicates that the framework structures are related. All the compounds have been characterized by powder X-ray diffraction, elemental analysis, infrared (IR) spectroscopic, thermogravimetric analysis (TGA), and photoluminescence studies.