Figure 4.
Crystal structure of [Zr(C12H18N3O6)(OH)]2 - 6 H2O (Zr-NOTA). Zr-NOTA crystalizes as a binuclear complex. The six coordinate monomers, which are defined by the Zr-NOTA subunits are bridged by two OH groups (O7A and O7B) and are related by the crystallographic inversion center at ½, ½, 0 in the unit cell. Only a partial numbering scheme is provided. Solvent molecules and hydrogen atoms are omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. The molecules are labeled to facilitate the identification of the symmetry related atoms only.