Selective Crystallization for Green Separations of Lanthanides Using 5-(Pyrimidyl)Tetrazolate

In an effort to develop facile, low-cost, and environmentally benign separations of lanthanides, the coordination chemistry and selective crystallization of Ln(3+) cations with the water-soluble ligand 5-(pyrimidyl)tetrazolate (pmtz) have been investigated . The wide range of coordination modes of pmtz allows for discrimination between these cations, and five distinct compound types can be prepared that are dependent on the lanthanide employed. La3+ leads to the formation of [La(pmtz)(2)(H2O)(6)]Cl (S1). [Ln(pmtz)(3)(H2O)(3)]center dot(3+n)H2O is obtained with Ce(3+ )and Pr3+ (S2). Ce3+ can also form [(Ce(pmtz)(2)(H2O)(3))(2)(mu-pmtz)](pmtz)center dot 11H(2)O (S3). [(Ln(pmtz)(2)(H2O)(3))(2)(mu-pmtz)](2)(pmtz)(2)center dot 14H(2)O (S4) is formed with Nd3+ and Sm3+. The smaller Ln(3+) cations , Dy3+ to Lu3+ , all yield [Ln(H2O)(8)] (pmtz)(3)center dot 3H(2)O (S5). This selective crystallization of Ln(3+) cations based primarily on ionic radii provides a simple method for achieving group separations.

Automated summary

This research investigates the coordination chemistry and selective crystallization of lanthanide cations with a water-soluble ligand, providing a simple method for achieving group separations based on ionic radii.