Spontaneous resolution of lanthanide coordination polymers with 2-hydroxypyrimidine-4,6-dicarboxylic acid

Abstract

The multidentate ligand 2-hydroxypyrimidine-4,6-dicarboxylic acid (H₃opdc) has been prepared by permanganate oxidation of 2-chloro-4,6-dimethylpyrimidine. The first series of lanthanide coordination polymers of 2-oxopyrimidine-4,6-dicarboxylate (opdc³⁻), [Ln(opdc)(H₂O)₂] (Ln = Eu, Gd, Tb, Dy, Er, Yb) have been synthesized viahydrothermal reaction of H₃opdc and the corresponding lanthanide nitrates. The complexes crystallized similarly in the chirodescriptive space group R32 with 1D hydrophilic ultramicrochannels. Spontaneous resolution occurred during the crystallization process, as the enantiomers were obtained and confirmed by structural analysis of selected crystals and the circular dichroism spectra. The Eu and Tb complexes show intense ligand sensitized photoluminescence.