10.1021/acs.organomet.5b00397.s001 Marcus W. Drover Marcus W. Drover Heather C. Johnson Heather C. Johnson Laurel L. Schafer Laurel L. Schafer Jennifer A. Love Jennifer A. Love Andrew S. Weller Andrew S. Weller Reactivity of an Unsaturated Iridium(III) Phosphoramidate Complex, [Cp*Ir{κ<sup>2</sup>‑<i>N</i>,<i>O</i>}][BAr<sup>F</sup><sub>4</sub>] American Chemical Society 2015 0.5 equiv MeCN coordination bond activation Reactivity screening H 2SiPh H 2BMes BArF phosphoramidate ligand Lewis bases NMR Cp 190 K mesityl borane 2015-08-10 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Reactivity_of_an_Unsaturated_Iridium_III_Phosphoramidate_Complex_Cp_Ir_sup_2_sup_i_N_i_i_O_i_BAr_sup_F_sup_sub_4_sub_/2220694 The three-legged piano stool complex [Cp*Ir­(κ<sup>2</sup>-<i>N</i>,<i>O</i>-Xyl­(<u>N</u>)­P­(<u>O</u>)­(OEt)<sub>2</sub>)­(Cl)], [<b>1</b>] (Cp* = η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>, Xyl = 2,6-dimethylphenyl), was prepared from reaction of 0.5 equiv of [Cp*IrCl<sub>2</sub>]<sub>2</sub> with the sodiated phosphoramidate ligand Na­[Xyl­(N)­P­(O)­(OEt)<sub>2</sub>]. Treatment of [<b>1</b>] with Na­[BAr<sup>F</sup><sub>4</sub>], [BAr<sup>F</sup><sub>4</sub>] = [B­(C<sub>6</sub>H<sub>3</sub>(CF<sub>3</sub>)<sub>2</sub>)<sub>4</sub>], led to the formation of the 16-electron two-legged piano stool species [Cp*Ir­(κ<sup>2</sup>-<i>N</i>,<i>O</i>-Xyl­(<u>N</u>)­P­(<u>O</u>)­(OEt)<sub>2</sub>)]­[BAr<sup>F</sup><sub>4</sub>], [<b>2</b>]­[BAr<sup>F</sup><sub>4</sub>], which was characterized in both solution and solid state. Reactivity screening revealed that complex [<b>2</b>]­[BAr<sup>F</sup><sub>4</sub>] undergoes addition of a variety of Lewis bases to afford the corresponding 18-electron adducts with concomitant movement of the phosphoramidate ligand from κ<sup>2</sup>-<i>N</i>,<i>O</i> to κ<sup>1</sup>-<i>N</i>, [Cp*Ir­(κ<sup>1</sup>-<i>N</i>-Xyl­(<u>N</u>)­P­(O)­(OEt)<sub>2</sub>)­(L)<sub>2</sub>]­[BAr<sup>F</sup><sub>4</sub>]; L = CN<i>t</i>Bu, [<b>3</b>]­[BAr<sup>F</sup><sub>4</sub>], CNXyl, [<b>4</b>]­[BAr<sup>F</sup><sub>4</sub>], MeCN, [<b>7</b>]­[BAr<sup>F</sup><sub>4</sub>], bipy, [<b>8</b>]­[BAr<sup>F</sup><sub>4</sub>]; bipy = 2,2′-bipyridine. For complex [<b>7</b>]­[BAr<sup>F</sup><sub>4</sub>], variable-temperature <sup>31</sup>P­{<sup>1</sup>H} NMR spectroscopy revealed that MeCN coordination was reversible between 238 and 190 K. To probe E–H (E = Si, B) bond activation, complex [<b>2</b>]­[BAr<sup>F</sup><sub>4</sub>] was treated with H<sub>2</sub>SiPh<sub>2</sub>, providing the five-membered iridacycle [Cp*Ir­(κ<sup>2</sup>-<i>N,Si</i>-Xyl­(<u>N</u>)­P­(O<u>Si</u>Ph<sub>2</sub>)­(OEt)<sub>2</sub>)]­[BAr<sup>F</sup><sub>4</sub>], [<b>9</b>]­[BAr<sup>F</sup><sub>4</sub>], via geminal Si–H activation, while use of mesityl borane, H<sub>2</sub>BMes (Mes = 2,4,6-trimethylphenyl), afforded the six-membered phosphoramidate-stabilized borane complex [Cp*Ir­(κ<sup>3</sup>-<i>N,H,H</i>-Xyl­(<u>N</u>)­P­(OB<u>H</u><sub><u>2</u></sub>Mes)­(OEt)<sub>2</sub>)]­[BAr<sup>F</sup><sub>4</sub>], [<b>10</b>]­[BAr<sup>F</sup><sub>4</sub>]. Complexes [<b>3</b>]­[BAr<sup>F</sup><sub>4</sub>] and [<b>9</b>]­[BAr<sup>F</sup><sub>4</sub>] were additionally characterized by single-crystal X-ray diffraction.