TY - DATA T1 - Planar Trimethylenemethane Dianion Chemistry of Lanthanide Metallocenes:  Synthesis, Structure, Density Functional Theory Analysis, and Reactivity of [(C5Me5)2Ln]2[μ-η3:η3-C(CH2)3] Complexes PY - 2006/12/20 AU - William J. Evans AU - Timothy M. Champagne AU - Joseph W. Ziller AU - Nikolas Kaltsoyannis UR - https://acs.figshare.com/articles/journal_contribution/Planar_Trimethylenemethane_Dianion_Chemistry_of_Lanthanide_Metallocenes_Synthesis_Structure_Density_Functional_Theory_Analysis_and_Reactivity_of_C_sub_5_sub_Me_sub_5_sub_sub_2_sub_Ln_sub_2_sub_sup_3_sup_sup_3_sup_C_CH_sub_2_sub_sub_3_sub_Complexes/3040480 DO - 10.1021/ja0645988.s001 L4 - https://ndownloader.figshare.com/files/4743967 KW - lutetium complexes KW - Lu case KW - lanthanide ion KW - Planar Trimethylenemethane Dianion Chemistry KW - bifunctional bisallylic reagent KW - metal radius KW - dianion complexes KW - shell examples KW - lanthanide metallocenes KW - 5Me KW - covalent interactions KW - Density Functional Theory Analysis KW - Synthetic routes KW - synthesizing examples KW - vinyl group KW - DFT calculations KW - TMM dianions KW - TMM product N2 - The unusual formation of planar trimethylenemethane (TMM) dianion complexes of lanthanide metallocenes, [(C5Me5)2Ln]2[μ-η3:η3-C(CH2)3] (Ln = Sm, 1; La, 2; Pr, 3; Nd, 4; Y, 5) has been examined by synthesizing examples with metals from La to Y to examine the effects of radial size on structure and to provide closed shell examples for direct comparison with density functional theory (DFT) calculations. Synthetic routes to 1−4 have been expanded from the [(C5Me5)2Ln][(μ-Ph)2BPh2]/neopentyl lithium reaction involving β-methyl elimination to a [(C5Me5)2Ln][(μ-Ph)2BPh2]/isobutyl lithium route. The synthetic pathways are sensitive to metal radius. To obtain 5, the methylallyl complex, (C5Me5)2Y[CH2C(Me)CH2], 6, was synthesized and treated with [(C5Me5)2YH]x. In the Lu case, the neopentyl complex [(C5Me5)2LuCH2C(CH3)3]x, 7, was isolated instead of the TMM product. X-ray crystallography showed that the metrical parameters of the planar TMM dianions in each complex are similar. The structural data have been compared with DFT calculations on the closed-shell lanthanum and lutetium complexes that suggest only limited covalent interactions with the lanthanide ion. Benzophenone (2 equiv) reacts with 1 to expand the original four-carbon TMM skeleton to a dianionic bis(alkoxide) ligand containing a symmetrically substituted CCH2 moiety in [(C5Me5)2Sm]2[μ-(OCPh2CH2)2CCH2], 8. In this reaction, the TMM complex reacts as a bifunctional bisallylic reagent that generates an organic framework containing a central vinyl group. ER -