Coordination behavior of L-aspartic acid: thermal, spectroscopic, magnetic and structural properties of aqua(L-aspartato)(2,2'-bipyridine)copper(II) trihydrate.

[Cu(L-asp)(H2O)(bpy)]x 3H2O crystallizes in the orthorhombic space group P212,21 with four formula units in a cell of dimensionsa = 21.978 (2) A, 6 = 1 1.275 (1) A, and c = 6.841 (1) A. The structure was solved by the heavy-atom method and refinedby least-squares calculations to R = 0.037 for 1640 independent reflections. The structure consists of a monomeric[Cu(L-asp)(bpy)H2O] molecule with three water molecules in the lattice. The geometry around Cu(II) is five-coordinateddistorted square pyramidal. The organic ligands act as bidentate in the basal plane, with a water molecule occupying theapical position. Thermogravimetric analysis shows the complete loss of water molecules in the 335-400 K temperaturerange. Infrared and ligand field spectroscopic results and variable-temperature magnetic measurements are interpretedin the light of the known structure.