Neodymium(III) Complexes with Bulky <i>a</i><i>nsa</i>-Bis(cyclopentadienyl) Ligands:  Synthesis and Use in Olefin Oligomerization Stéphane Bogaert Thomas Chenal André Mortreux Guy Nowogrocki Christian W. Lehmann Jean-François Carpentier 10.1021/om0006357.s001 https://acs.figshare.com/articles/journal_contribution/Neodymium_III_Complexes_with_Bulky_i_a_i_i_nsa_i_-Bis_cyclopentadienyl_Ligands_Synthesis_and_Use_in_Olefin_Oligomerization/3763797 The trivalent neodymium complexes [<i>rac</i>-{Me<sub>2</sub>Si(η<sup>5</sup>-2-SiMe<sub>3</sub>-4-<i>t</i>-Bu-C<sub>5</sub>H<sub>2</sub>)<sub>2</sub>}Nd(μ-Cl)<sub>2</sub>Li(THF)<sub>2</sub>] (<i>rac</i>-<b>3</b>), [<i>rac</i>-{Me<sub>2</sub>Si(η<sup>5</sup>-2,4-(SiMe<sub>3</sub>)<sub>2</sub>C<sub>5</sub>H<sub>2</sub>)<sub>2</sub>}Nd(μ-Cl)<sub>2</sub>Li(THF)<sub>2</sub>] (<i>rac</i>-<b>5</b>), and [{Me<sub>2</sub>Si(η<sup>5</sup>-2,4-(SiMe<sub>3</sub>)<sub>2</sub>C<sub>5</sub>H<sub>2</sub>)(η<sup>5</sup>-3,4-(SiMe<sub>3</sub>)<sub>2</sub>C<sub>5</sub>H<sub>2</sub>)}Nd(μ-Cl)<sub>2</sub>Li(THF)<sub>2</sub>] (<i>C</i><sub>1</sub>-<b>6</b>) have been prepared and their structures investigated by NMR and X-ray crystallography. These new chlorolanthanocenes, when combined in situ with a dialkylmagnesium cocatalyst, initiate the polymerization of ethylene and 1-octene to yield di(oligoalkyl)magnesium species, which can be finally hydrolyzed to oligomers. Bulky bridged complexes <i>rac</i>-<b>3</b>, <i>rac</i>-<b>5</b>, and <i>C</i><sub>1</sub>-<b>6</b> gave significantly more active catalysts for 1-octene oligomerization (<i>M</i><sub>n</sub> = 400−1300, <i>M</i><sub>w</sub>/<i>M</i><sub>n</sub> = 1.11−1.65) than systems based on nonbridged complexes [(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>Nd(μ-Cl)<sub>2</sub>Li(Et<sub>2</sub>O)<sub>2</sub>] (<b>1</b>) and [(η<sup>5</sup>-1,3-(SiMe<sub>3</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>)<sub>2</sub>Nd(μ-Cl)<sub>2</sub>Li(THF)<sub>2</sub>] (<b>7</b>). Ethylene oligomerization (<i>M</i><sub>n</sub> = 400−5000) was best achieved with complexes <b>1</b> and <i>rac</i>-<b>3</b>, as important catalyst decay occurred with bridged bis(trimethylsilyl) systems <i>rac</i>-<b>5</b> and <i>C</i><sub>1</sub>-<b>6</b>. 2000-12-06 00:00:00 SiMe 2 C 5 H 3 2 C 5 H 2 trivalent neodymium complexes Bulky bridged complexes rac Nd M n Si NMR C 1 Li