Pyridine complexes of rare earth element trichlorides. syntheses and crystal structures of [YCl3(py)4] and [LnCl3(py)4]•0.5 py with Ln = La and Er

The pyridine complexes [YCl3(py)(4)] (1), [LaCl3-(py)(4)] .0.5 py (2 . 0.5 py), and [ErCl3(py)(4)] . 0.5 py (3 . 0.5 py) have been prepared from the diacetone-alcohol complexes [LnCl(3)(DAA)(2)] or directly from the metal trichlorides with excess pyridine to give colourless, only sparingly moisture sensitive crystals. They were characterized by IR spectroscopy and by crystal structure determinations. 1: Space group Pbca, Z = 16, lattice dimensions at -80degreesC: a = 1647.4(1), b = 1743.1(1), c = 3190.5(1) pm, R-1 = 0.031 2 . 0.5 Py: Space group P2(1)/n, Z = 4, lattice dimensions at -80degreesC: a = 978.9(1), b = 1704.5(1), c=1589.5(1) pm, beta = 103.61(1)degrees, R-1 = 0.0281. 3 . 0.5 Py: Space group P2(1)/n, Z = 4, lattice dimensions at -80degreesC: a = 970.1(1), b = 1706.4(1), c = 1566.1(1) pm, beta = 103.46(1)degrees, R-1 = 0.0232. All complexes realize monomeric molecular structures with the metal atom in a distorted pen tagonal-bipyramidal coordination. One of the chlorine atoms and the four pyridine molecules are in the equatorial plane.