THE FORMATION AND MOLECULAR-STRUCTURE OF (ETA(5)-C5H5)(3)SM-CENTER-DOT-OC4H8

Reaction of 1/2 mole ratio of (eta(5)-C5H5)SmCl2.3THF and NaC=CCH2OCH2CH=CH2 in THF solution resulted in the formation of (eta(5)-C5H5)(3)Sm.OC4H8; the complex crystallizes in monoclinic space group P2(1)/n with unit cell constants a=8.254(5), b=24.63(1), c=8.339(3) Angstrom, beta=101.33(5)degrees and D-c=1.67 g/cm(3) for Z=4. Refinement has led to a final R value of 0.041 based on 2106 independent observed reflections. The THF molecule is coordinated to the samarium atom at a Sm-O distance of 2.522(6) Angstrom. The Sm-C(cyclopentadienyl) bond lengths range from 2.70(1) to 2.80(1) Angstrom and average 2.742(1) Angstrom. A comparison of some significant structural parameters along the isostructural series (eta(5)-C5H5)(3)Ln.THF(Ln=La, Pr, Nd, Gd, Dy, Lu and Sm) with the ionic radii of Ln(3+) was made.