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.