REACTIVITY OF (C5ME5)2SM WITH ARYL-SUBSTITUTED ALKENES - SYNTHESIS AND STRUCTURE OF A BIMETALLIC STYRENE COMPLEX THAT CONTAINS AN ETA-2-ARENE LANTHANIDE INTERACTION

(C5Me5)2Sm (1) and (C5Me5)2Sm(THF)2 (2) isomerize cis-stilbene to trans-stilbene. The stoichiometric reaction of 1 with stilbene forms [(C5Me5)2Sm]2(μ-η2:η4-PhCHCHPh) (3). 1 reacts with styrene to form [(C5Me5)2Sm]2(μ- η2:η4-CH2CHPh) (4). In both 3 and 4, the two (C5Me5)2Sm units coordinate on opposite sides of the alkene bond such that the Sm–Sm vector bisects the bond at right angles. In each complex, phenyl carbon atoms are oriented to interact with one of the samarium centers. In 4, the Sm–C(C5Me5) distances range from 2.678 (18) to 2.847 (18) Å, the Sm–C(alkene) distances range from 2.537 (15) to 2.732 (15) Å, and two carbon atoms of the phenyl ring are positioned 2.772 (17) and 2.850 (16) Å from one samarium atom. 3 crystallizes from hexane in space group with a = 12.156 (6) A, b = 14.405 (9) Å, c = 15.628 (2) Å, and V = 2737 (2) Å3 with Z = 2 for Dcalcd = 1.24 g cm–3. 4 crystallizes from hexane in space group Pbca with a = 21.169 (4) Å, b = 17.663 (3) Å, c = 23.713 (5) Å, and V = 8866 (3) Å3 with Z = 8 for Dcalcd = 1.417 g cm–3. Least-squares refinement of the model based on 3134 observed reflections converged to a final RF = 6.2%. © 1990, American Chemical Society. All rights reserved.