Synthesis and Characterization of Bulky Cationic Arylalkylaluminum Compounds KlisTomasz PowellDouglas R. WojtasLukasz WehmschulteRudolf J. 2011 The cationic <i>m</i>-terphenyl-substituted organoaluminum compounds [Dipp*AlEt][CH<sub>6</sub>B<sub>11</sub>Cl<sub>6</sub>] (<b>3</b>; Dipp* = 2,6-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>−), [DcpAlEt][CH<sub>6</sub>B<sub>11</sub>Cl<sub>6</sub>] (<b>4</b>; Dcp = 2,6-(2,6-Cl<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>−), [Dipp*AlEt][CH<sub>6</sub>B<sub>11</sub>I<sub>6</sub>] (<b>5</b>), and [DcpAlEt][CH<sub>6</sub>B<sub>11</sub>I<sub>6</sub>] (<b>6</b>) have been obtained by ethide elimination through trityl or preferably silylium salts from the precursors Dipp*AlEt<sub>2</sub> (<b>1</b>) and DcpAlEt<sub>2</sub> (<b>2</b>). The crystal structures of compounds <b>3</b>−<b>5</b> reveal the presence of cation−anion adducts involving two halides of the carborane anions, and the NMR spectroscopic data and solubility properties indicate such an interaction for <b>6</b>. The interactions of the hexaiodocarborane anion with the [Dipp*AlEt]<sup>+</sup> cation are stronger than those of the hexachlorocarborane anion. Interestingly, cation···anion contacts are preferred to intramolecular Al···Cl interactions in the Dcp species <b>4</b>. Compound <b>4</b> forms the bis-amine adduct [DcpAlEt(NH<sub>2</sub><i>t</i>-Bu)<sub>2</sub>][CH<sub>6</sub>B<sub>11</sub>I<sub>6</sub>] (<b>8</b>) upon exposure to <i>t</i>BuNH<sub>2</sub>, and compounds <b>3</b> and <b>4</b> slowly catalyze the alkylation of benzene with 1-hexene. The compounds have been characterized by <sup>1</sup>H, <sup>13</sup>C, and <sup>11</sup>B NMR spectroscopy and by X-ray crystallography in the case of <b>1</b>−<b>5</b>, <b>7</b>, and <b>8</b>.