Spontaneous resolution of a chiral polyoxometalate: Synthesis, crystal structures and properties

Two enantiomerically pure chiral POM-based compounds, [(CH3)2NH2]10[Zr(PW11O39)2] · 10H2O (Left-1, L-1 for short and Right-1, R-1 for short) have been prepared by conventional aqueous solution method without a chiral auxiliary and structurally characterized by single-crystal X-ray diffraction. The structures of L-1 and R-1 contain two lacunary [PW11O39]7− units, each acting as a tetra-dentate ligand, the ZrIV cation sandwiched between two [PW11O39]7− anions is of eight coordination and occupies a distorted square antiprismatic geometry. The circular dichroism spectra confirmed the occurrence of spontaneous resolution and the enantiomeric nature of L-1 and R-1. Cyclic voltammetric experiment for 1 represents two redox peaks corresponding to the redox processes of [PW11O39]7− in the potential range from −1000 to 1000 mV.