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>]
Marcus
W. Drover
Heather C. Johnson
Laurel L. Schafer
Jennifer A. Love
Andrew S. Weller
10.1021/acs.organomet.5b00397.s001
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.
2015-08-10 00:00:00
0.5 equiv
MeCN coordination
bond activation
Reactivity screening
H 2SiPh
H 2BMes
BArF
phosphoramidate ligand
Lewis bases
NMR
Cp
190 K
mesityl borane