The coordination of the tetraselenidoantimonate [SbSe4]3- anion with trivalent lanthanide ions tuned by ethylene polyamines.

The solvothermal synthetic system Ln/Sb/Se (Ln = La, Eu) was investigated in different ethylene polyamines, and a series of lanthanum and europium selenidoantimonates [La(en)(2)(dien)(eta(2)-SbSe(4))] (Ia), [La(dien)(2)(mu-eta(1),eta(2)-SbSe(4))] (Ib), [La(trien)(2)(H(2)O)]SbSe(4) (Ic), [La(en)(trien)(mu-eta(1),eta(2)-SbSe(4))] (Id), [Eu(en)(2)(dien)(SbSe(4))] (IIa), [Eu(en)(trien)(eta(2)-SbSe(4))] (IIb), and [Eu(dien)(2)(eta(2)-SbSe(4))] (IIc) (en = ethylenediamine, dien = diethylenetriamine, trien = triethylenetetramine) were prepared. A systematic investigation of the crystal structures showed that the soft Lewis basic ligand SbSe(4) can be tuned to coordinate to the hard Lewis acidic lanthanide ions as a monodentate ligand, mono-SbSe(4); a bidentate chelating ligand, eta(2)-SbSe(4); or a tridentate bridging ligand, mu-eta(1),eta(2)-SbSe(4), by the ethylene polyamines or mixed ethylene polyamines used in the syntheses. The SbSe(4) anion exhibited different coordination modes for La(3+) and Eu(3+) ions in the presence of the same ethylene polyamine because of the different coordination numbers of La(3+) and Eu(3+) ions.