ELECTRON-STRUCTURE OF ORGANOMETAL COMPLEXES OF F-ELEMENTS .33. ESTER ADDUCTS OF TRIS-(ETA-5-CYCLOPENTADIENYL)LANTHANIDE(III), IDEAL LATTICE FOR SINGLE-CRYSTAL OPTICAL ANALYSIS OF LANTHANOID IONS IN ORGANOMETAL ENVIRONMENT

Single crystals of various ester adducts derived from tris (eta5-cyclopentadienyl)-lanthanide(III) (Cp3Ln; Ln = La, Pr, Sm, Th, Er, Tm) have been grown and were inspected by a polarizing microscope. As all these crystals exhibit straight extinction, the unit cell is essentially orthorhombic. The crystal and molecular structures of the butylacetate (BA) adduct derived from Cp3La were determined. Cp3La . BA crystallizes in the molecular space group P2(1)/n with four molecules in the unit cell. The monoclinic angle beta = 91.55-degrees is close to the right angle of the rhombic system and the pseudo-threefold axes of the individual molecules make angles of \5.4-degrees\ and \174.6-degrees\, respectively, with the monoclinic b axis. For practical purposes Cp3La.BA may be considered as being orthorhombic with the molecules aligned. Selected regions of the alpha-, sigma-, and pi-absorption spectra of Cp3La.BA: Pr are presented and interpreted.