Structural variety in nitrate complexes of the heavy lanthanides with 2,2 ': 6 ',2 ''-terpyridine, and stereoselective replacement of nitrate

Structural studies show that the solvolysis of a nitrate group in the heavy lanthanide complexes [Ln(terpy)(NO3)(3)] {Ln = Yb, Lu; terpy = 2,2': 6', 2"-terpyridine} is stereoselective. In the complexes [Ln(terpy)(NO3)(3)(EtOH)], the `equatorial nitrate group', which lies in the same plane as the terpy ligand, coordinates in a monodentate fashion and the vacant coordination site is filled by an ethanol molecule. Similarly, in the unusual complexes [Yb(terpy)(NO3)(2)(H2O)(2)][NO3] and [Lu(terpy)(NO3)(2)(H2O)( EtOH)][NO3], two water molecules or a water and an ethanol molecule are bound to the metal in preference to the nitrate and lie in the same plane as the terpy ligand.