Inorganic Chemistry
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F
(10 mL). This mixture was allowed to stir for 1 h, yielding a
glovebox. A solution of [H·(OEt ) ][BAr ] (95 mg, 0.094 mmol)
2 2 4
homogeneous cyan solution. This solution was chilled to −78 °C, and
a solution of MeMgCl in THF (0.5 M, 0.560 mmol) was added in
three 370 μL portions over 3 h. The mixture was allowed to warm
slowly to room temperature and then was concentrated to ca. 1 mL.
in Et O (1.5 mL) similarly cooled to −78 °C was added to this
2
suspension in one portion with stirring. Residual acid was dissolved in
cold Et O (0.25 mL) and added subsequently. This mixture was
2
allowed to stir for 5 min at −78 °C, before being transferred to a
precooled Schlenk tube equipped with a stir bar. The original reaction
1
,4-Dioxane (2 mL) was added, and the resultant suspension was
stirred vigorously for at least 2 h before filtration. The filtrate was
concentrated to a tacky red-brown solid, which was extracted with 1:1
C H −pentane (10 mL), filtered over Celite, and lyophilized to yield
vial was washed with cold Et O (0.25 mL), which was added sub-
sequently to the Schlenk tube. KC8 (16 mg, 0.119 mmol) was
2
suspended in cold Et O (0.75 mL) and added to the reaction mixture
6
6
2
the product as a red powder (96 mg, 0.141 mmol, 83%). Crystals
suitable for XRD were grown via the slow evaporation of a pentane
over the course of 1 min. The Schlenk tube was then sealed, and the
reaction was allowed to stir for 40 min at −78 °C before being warmed
to room temperature and stirred for 15 min.
1
solution. H NMR (300 MHz, C D ): δ 7.28 (br, 3H), 6.82 (m, 9H),
6
6
2
.82 (oct, −CH, 3H), 2.09 (sept, −CH, 3H), 1.49 (m, 18H), 1.06 (dd,
31
1
−
CHCH , 9H), 0.30 (dd, −CHCH , 9H). P{ H} NMR (121 MHz,
3
3
ASSOCIATED CONTENT
Supporting Information
Crystallographic data in CIF format, spectroscopic data, experi-
−1
■
C D ): δ 47.39. IR (thin film, cm ): 2057 (N ). Anal. Calcd for
6
6
2
*
S
C H CoN P : C, 65.48; H, 8.02; N, 4.13. Found: C, 64.14; H, 8.36;
37
54
2 3
N, 4.03.
(CP )Co(N )][BAr ] (6). 5 (75 mg, 0.11 mmol) and [Cp Fe][BAr ]
F
4
F
[
mental details, additional data for NH production experiments,
3
3
2
2
4
(
3
122 mg, 0.12 mmol) were dissolved separately in diethyl ether (ca.
mL each), and the ethereal solutions were cooled to −78 °C. The
F
chilled solution of [Cp Fe][BAr ] was added dropwise to the solution
2
4
of 5, and the resultant mixture was allowed to stir at low temperature
for 1 h. At this point, the mixture was allowed to warm to room tem-
perature before filtration over Celite and concentration to ca. 2 mL.
The concentrated filtrate was layered with pentane and placed in a
freezer at −35 °C to induce crystallization. Decanting the mother
liquor off crystalline solids and washing thoroughly with pentane yields
AUTHOR INFORMATION
■
Author Contributions
6
as dark-green-brown crystals (147 mg, 0.095 mmol, 86%). Crystals
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
suitable for XRD were grown by the slow diffusion of pentane vapors
into an ethereal solution of 6 at −35 °C. μ (5:1 toluene-d −THF-d ,
eff
8
8
1
Evans’ method, 23 °C): 3.49 μ . H NMR (300 MHz, C D ): δ 17.22,
B
6
6
F
F
9
−
.94, 8.24 ([BAr ]), 7.72 ([BAr ]), 3.13, 2.57, +1.5 to −2 (br, m),
4
4
Notes
−
1
3.68. IR (cm ): 2182 (N , thin film), 2180 (N , solution).
2
2
The authors declare no competing financial interest.
Elemental analysis shows low values for N consistent with a labile
N ligand. Anal. Calcd for C H BCoF N P : C, 53.75; H, 4.31; N,
2
69 66
24
2 3
ACKNOWLEDGMENTS
1
.82. Found: C, 53.86; H, 4.31; N, 0.27. Note: The magnetic moment
■
for 6 in solution may be complicated by some degree of solvent
This work was supported by the NIH (Grant GM 070757) and
the Gordon and Betty Moore Foundation, and through the
NSF via a GRFP award to T.J.D.C.
exchange for N at the Co center, as described in the text.
2
[
(NArP )CoCl][BPh ]. THF (5 mL) was added to a solid mixture of
3 4
NArP (58 mg, 91.2 mmol), CoCl (12 mg, 92.4 mmol), and NaBPh
3
2
4
(
31 mg, 90.6 mmol). The reaction was stirred for 4 h at room
REFERENCES
temperature, during which the color evolved from yellow to green to
purple. The solvent was removed in vacuo, and the residue was taken
up in dichloromethane. The suspension was filtered over a plug of
Celite, and the filtrate was dried, yielding a purple powder (86 mg,
■
(
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8
2.1 mmol, 90%). Single crystals were grown by the slow evaporation
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of a saturated solution of [(NArP )CoCl][BPh ] in diethyl ether−
dichloromethane (1:2, v/v). H NMR (CD Cl , 300 MHz): δ 177.77,
3
3
4
1
2
2
7.50, 23.78, 13.48, 12.96, 7.37, 7.08, 6.92, 4.41, 1.50, −3.60, −9.81.
−1 −1
UV−vis [THF; λ, nm (ϵ, L cm mol )]: 564 (452), 760 (532). μ
eff
(
CD Cl , Evans’ method, 23 °C): 3.97 μ . Anal. Calcd for
2 2 B
C H BClCoNP : C, 72.10; H, 7.68; N, 1.33. Found: C, 71.97; H,
63
80
3
7
.76; N, 1.30.
NH Quantification. A Schlenk tube was charged with HCl (3 mL
3
of a 2.0 M solution in Et O, 6 mmol). Reaction mixtures were vacuum
2
transferred into this collection flask. Residual solid in the reaction
vessel was treated with a solution of [Na][O-t-Bu] (40 mg, 0.4 mmol)
in 1,2-dimethoxyethane (1 mL) and sealed. The resulting suspension
was allowed to stir for 10 min before all volatiles were again vacuum-
transferred into the collection flask. After completion of the vacuum
transfer, the flask was sealed and warmed to room temperature. The
solvent was removed in vacuo, and the remaining residue was
dissolved in H O (1 mL). An aliquot of this solution (20 μL) was then
analyzed for the presence of NH (present as [NH ][Cl]) by the
indophenol method. Quantification was performed with UV−vis
spectroscopy by analyzing the absorbance at 635 nm.
2
3
4
17
Mu
E.; Brennessel, W. W.; Holland, P. L. Science 2011, 334, 780.
(h) Curley, J. J.; Cook, T. R.; Reece, S. Y.; Muller, P.; Cummins, C. C.
̈
ller, P. Chem. Commun. 2012, 48, 1851. (g) Rodriguez, M. M.; Bill,
Standard NH3 Generation Reaction Procedure with 2.
̈
[
(TPB)Co(N )][Na(12-c-4) ] (2.2 mg, 0.002 mmol) was suspended
J. Am. Chem. Soc. 2008, 130, 9394. (i) Fryzuk, M. D.; Kozak, C. M.;
Bowdridge, M. R.; Patrick, B. O.; Rettig, S. J. J. Am. Chem. Soc. 2002,
124, 8389.
2
2
in Et O (0.5 mL) in a 20 mL scintillation vial equipped with a stir bar.
2
This suspension was cooled to −78 °C in a cold well inside of an N2
F
Inorg. Chem. XXXX, XXX, XXX−XXX