A rare case of 2D+1D → 2D Cd(II) coordination polymer without any entanglements: Synthesis, structure and luminescent property

The reactions of CdCl2·2.5H2O with mixed ligands, H2tfbdc and hmt, under different metal-to-ligand ratios, afford two coordination polymers, namely, [Cd(hmt)(tfbdc)(H2O)2]2·3H2O (1) and {[NH4]2[Cd2(H2hmt)(tfbdc)2Cl4][Cd(H2hmt) (tfbdc)Cl2]}·2H2O (2). Both the complexes have been structurally characterized by X-ray data. Complex 1 has a 2D rectangular grid built up by tfbdc2– and hmt ligands, while 2 consists of distinct 1D anionic ladder [Cd2(H2hmt)(tfbdc)2Cl4]2‒ and 2D grid [Cd(H2hmt)(tfbdc)Cl2] in a crystal. Further, in 2, the 2D net is parallel to the 1D ladder without mutual entanglement or interdigitation. Despite the hydrogen bond interactions and the F···F interactions, only a 2D supermolecular structure is formed in 2. Thus, compound 2 is the first case of 2D+1D→2D coordination polymer without any entanglements