pH Dependent Synthesis of NdIII Coordination Compounds Based on Bifunctional 5-(4-Pyridyl)tetrazole-2-acetic Acid

The NdIII coordination compounds [Nd(4-pytza)3(H2O)2]·2H2O (1) and [Nd(4-pytza)2(H2O)4]Cl·2H2O (2) [H4-pytza = 5-(4-pyridyl)tetrazole-2-acetic acid] were synthesized by reactions of K4-pytza and NdCl3·6H2O at different pH values. Single crystal X-ray diffraction analysis reveals that 4-pytza ligands in 1 in a μ1,3-COO syn-syn or μ1,1,3-COO bridging mode coordinate to two central NdIII atoms to display a dinuclear unit, which is connected by one of these 4-pytza ligands acting in end-to-end bridging mode to form a 1D ladder-like chain. Different from 1, each 4-pytza in 2 with a μ1,3-COO syn-anti bridging mode coordinates to two NdIII atoms to display a 1D zigzag chain. Furthermore, the luminescence properties of 1 and 2 were investigated at room temperature in the solid state.