ELECTRON-STRUCTURE OF ORGANOMETAL COMPLEXES OF F ELEMENTS .30. CRYSTAL AND MOLECULAR-STRUCTURES OF ADDUCTS WITH UNUSUAL CRYSTALLIZATION DERIVED FROM TRIS-(ETA-5-CYCLOPENTADIENYL)LANTHANOID(III)

The crystallizing properties of approximately 150 adducts derived from tris(eta(5)-cyclopentadienyl) lanthanide(III) (Cp3Ln) and Cp'3Ln (Cp' = C5H5R; R = methyl, ethyl, t-butyl, benzyl, phenyl, trimethylsilyl) have been examined. Transparent single crystals which crystallize in the shape of distorted hexagonal plates of cross sections up to 200 mm2 could be grown for the n-butylacetate (BA) adduct of the early members of the Cp3Ln series and for the acetonitrile adducts for Cp3Gd and Cp3Tb. The crystal and molecular structures of Cp3Pr.BA(1) and Cp3Tb.NCCH3 (2) were determined. 1 crystallizes in the molecular space group P2(1)/n with four molecules in the unit cell, and 2 in the triclinic space group P1BAR(Z = 2). The monoclinic angle beta = 91.58-degrees of 1 is close to the right angle of the rhombic system and the pseudo threefold axes of the individual molecules make angles of \4.97-degrees\and\175.03-degrees\, respectively, with the monoclinic b axis. For practical purposes 1 may be considered as being rhombic with the molecules aligned along the b axis. Thus, the individual molecules may be easily oriented with respect to a static magnetic field or the electric field vector of linearly polarized radiation. The alpha absorption spectrum of the spin allowed transitions of 1 is presented and some peculiarities are discussed.