2
708 Organometallics, Vol. 29, No. 12, 2010
Punji et al.
tBu
cycles and stored in an argon-atmosphere glovebox. ( PCP)-
NMR (125.7 MHz, C
(s br, 2C, Aryl-C), 129.6 (s br, 2C, Aryl-C), 129.2 (s, 1C, Aryl-C),
41.2 (s br, 12C, Ad-CH ), 40.5 (s, 12C, Ad-CH ), 37.3 (s br, 4C,
6
D
6
): δ 138.2 (s br, 1C, Aryl-C), 134.5
3,5 iPr
8 tBu
, and( POCOP)IrH
9,10
2
IrH ,
(
PCP)IrH
4
2
werepreparedas
described previously. Di-1-adamantylphosphine was used as
purchased from Strem. All other reagents were obtained from
commercial sources andused asreceived. Catalytic reactionswere
monitored using a Focus gas chromatograph with a 30 m ꢀ
2
2
Ad-C-P), 29.4 (vt, JPC = 4.2 Hz, 12C, Ad-CH), 20.3 (vt, JPC
19.1 Hz, 2C, CH -P).
=
2
Ad
Ad
Synthesis of ( PCP)IrH
(0.5 g, 0.53 mmol) in toluene (20 mL) was added dropwise a
solution (1.0 M in THF) of LiBEt H (0.53 mL, 0.53 mmol) at
room temperature under a H atmosphere. The dark orange
2
. To a solution of ( PCP)IrHCl
0
5
.25 mm capillary column. NMR spectra were recorded on 400 or
1
00 MHz Varian spectrometers, and H NMR spectra are
3
3
1
1
referenced to residual protio solvent. P{ H} NMR chemical
shifts are referenced to an external standard, Me P in mesitylene-
2
reaction mixture became colorless upon stirring for 1 h and was
then cannula-filtered to remove the precipitate. The filtrate was
evaporated under vacuum and dried overnight to obtain a
3
d12 solvent (δ -62.4 ppm), in a capillary tube.
Acceptorless Dehydrogenation of Alkanes. In a typical experi-
ment, in the argon-atmosphere glovebox, an alkane solution
of catalyst (1.0 mM) was charged into a reactor consisting of a
Ad
2
crystalline compound of ( PCP)IrH with a minor amount of
Ad
(
PCP)IrH . The mixture was dried under vacuum at 120 °C
4
Ad
5
1
mL cylindrical bulb fused to a water-jacketed condenser (ca.
5 cm in length). The top of the condenser was fused to two
overnight to obtain exclusively ( PCP)IrH
(73%). Anal. Calcd for C48 69IrP : C, 64.04; H, 7.73. Found:
C, 63.79; H, 7.39. H NMR (500 MHz, toluene-d ): δ 7.45 (d,
JHH = 7.5 Hz, 2H, Ar-H), 7.21 (t, J = 6.8 Hz, 1H, Ar-H),
2
. Yield: 0.35 g,
H
2
1
Kontes high-vacuum valves and an Ace Glass “adjustable elec-
trode ace-thred adapter”. The cylindrical bulb was fully im-
mersed in an oil bath held at 230 °C, resulting in vigorous reflux
8
3
3
HH
2
3.61 (vt, JPH = 4.0 Hz, 4H, 2 CH
0
2
), 2.14 (d, JHH
= 11.0 Hz, 12H, Ad-CH
0
= 12.0 Hz,
2
), 2.08 (d, J
of the reaction solution. Escape of H
2
from the system is enabled
12H, Ad-CH
R
(s, 12H, Ad-CH ), 1.63 (d, J
H
H
2
R
0
), 1.83
= 12.0 Hz, 12H, Ad-CH ),
by a continuous argon stream above the condenser. The reaction
was monitored by GC analysis.
0
β
= 10.5 Hz, 12H, Ad-CH
HH
γ
=
2
1.57 (d, J
2
0
0
), -19.15 (t, J
H H
γ
PH
3
1
1
Sealed-Tube Reactions. Sealed-tube reactions were conducted
as follows. The catalyst solution, 10.0 mM in alkane or alkane/
olefin, was charged into a long NMR tube, and a capillary,
containing external standard solutions, was introduced into it
inside the glovebox. The tube was flame-sealed under vacuum
and then placed in a preheated sand bath inside an oven. The
tube was periodically removed from the oven, and the reaction
was monitored by NMR spectroscopy. After this periodic
monitoring, the solution was transferred into a J-Young valved
9.25 Hz, 2H, Ir-H). P{ H} NMR (202.3 MHz, toluene-d
8
): δ
): δ 137.6 (s br, Ar-C),
131.9 (s br, Ar-C), 126.7 (s br, 2C, Ar-C), 120.4 (m, Ar-C), 41.5
(s br, 12C, Ad-CH ), 40.4 (s, 12C, Ad-CH ), 37.6 (s br, 4C, Ad-
C-P), 29.9 (m, 12C, Ad-CH), 29.4 (vt, JPC = 4.3 Hz, 2C, CH -P).
Synthesis of ( PCP)Ir(CO). To a solution of ( PCP)IrH
1
3
1
6 6
81.2 (s). C{ H} NMR (125.7 MHz, C D
2
2
2
Ad
Ad
2
(0.02 g, 0.022 mmol) in benzene-d (0.6 mL) in a J-Young NMR
6
tube was added norbornene (0.006 g, 0.063 mmol), and the
reaction mixture was left at room temperature overnight to
obtain ( PCP)Ir(norbornene). The solvent and excess norbor-
Ad
NMR tube inside the glovebox, H gas was then added to the
2
solution on a high-vacuum line, and the percentage of regener-
ated product (tetrahydride) was determined by NMR.
Synthesis of ( PCP-H). A mixture of 1,3-dibromoxylene
nene were removed under vacuum, and fresh solvent and CO
(1 atm) were then added. The tube was shaken for 5 min as the
Ad
1
solution turned yellow. H NMR (400 MHz, C
6
D
6
): δ 7.39 (d,
3
3
(
0.44 g, 1.67 mmol) and di-1-adamantylphosphine (1 g, 3.33
JHH = 7.6 Hz, 2H, Ar-H), 7.18 (t, J = 6.4 Hz, 1H, Ar-H),
HH
2
mmol) in degassed acetone (40 mL) was heated to reflux for 24 h.
The white precipitate formed was separated from the mother
liquor by cannula filtration and then dried under vacuum. The
white salt was brought into the glovebox, benzene (40 mL) and
3.54 (vt, JPH = 3.4 Hz, 4H, 2 CH
2
), 2.32 (d, JHH
= 12.0 Hz, 12H, Ad-CH
= 11.6 Hz, 12H, Ad-CH
γ
0
= 11.6 Hz,
), 1.86(s,
), 1.57 (d,
). P{ H} NMR (161.9 MHz,
): δ 77.2 (s). C{ H} NMR (125.7 MHz, C ): δ 182.2 (t,
PC = 4.0 Hz, CO), 138.1 (vt, JPC = 11.3 Hz, Ar-C), 128.9 (s,
Ar-C), 126.0 (s, Ar-C), 120.6 (vt, JPC = 8.5 Hz, 2C, Ar-C), 41.4 (s,
12C, Ad-CH ), 37.5 (s, 12C, Ad-CH ), 37.1 (vt, JPC = 4.3 Hz,
12C, Ad-CH), 35.9 (vt, JPC = 14.3 Hz, 4C, Ad-C-P), 29.4 (vt,
2
12H, Ad-CH
12H, Ad-CH
R
), 2.25 (d, J
H
0
H
0
R
2
0
β
), 1.67 (d, JHH
= 11.6 Hz, 12H, Ad-CH
0
γ
2
J
31
1
0
H
H
1
3
1
Et
stirred overnight and then filtered to remove the Et
3
N (0.51 mL, 3.67 mmol) were added, and the mixture was
N HBr salt.
C
6
D
6
6 6
D
2
J
3
3
The mother liquor was then evaporated to dryness to obtain the
white crystalline product, which was recrystallized from toluene.
Yield: 1.04 g, (88%). Anal. Calcd for C H P : C, 81.54; H,
2
2
4
8
68 2
-1
-1
1
J
PC =2.3Hz, 2C, CH
2
-P). IR(hexane, cm ):νCO = 1916 cm .
The same complex was observed upon addition of CO directly to a
solution of ( PCP)IrH .
9
.69. Found: C, 80.92; H, 9.41. H NMR (500 MHz, C
6
6
D ): δ
3
.83 (s, 1H, Ar-H), 7.39 (d, JHH = 7.5 Hz, 2H, Ar-H), 7.26 (t,
7
Ad
3
2
HH = 7.7 Hz, 1H, Ar-H), 2.87 (d, JPH = 2.0 Hz, 4H, 2 CH
J
2
),
2
Ad
1
Synthesis of ( PCP)IrH(η -1,3-cyclooctadienyl) (6a and 6b).
1
2
.96 (s, 24H, 12 Ad-CH ), 1.88 (s, 12H, 12 Ad-CH ), 1.67 (s,
β
2
(R)
4H, 12 Ad-CH2(γ)). P{ H} NMR (202.3 MHz, C
Ad
31
1
To a solution of ( PCP)IrH
10 (0.5 mL) in a J-Young NMR tube was added norbornene
0.006 g, 0.063 mmol), and the reaction mixture was left at room
2
(0.02 g, 0.022 mmol) in p-xylene-
6
D
6
):δ29.6 (s).
1
3
1
2
d
(
C{ H} NMR (125.7 MHz, C D ):δ143.1 (d, J = 13.8 Hz, 2C,
6
6
PC
3
aryl ortho-C),132.2(t, JPC = 12.5 Hz, 1C, aryl ipso C), 128.7 (s, 2C,
Ad
2
aryl meta-C), 127.5 (s, 1C, aryl para-C), 41.7 (d, JPC = 11.4 Hz,
temperature overnight to obtain ( PCP)Ir(norbornene). The
solvent and excess norbornene were removed under vacuum,
and fresh solvent and 1,3-cyclooctadiene (0.028 mL, 0.22 mmol)
were added in an argon-atmosphere glovebox. After allowing
the solution to remain at room temperature for 3 h, the solvent
and excess 1,3-cyclooctadiene were removed. The compound
was then dissolved in fresh p-xylene-d10, and NMR spectra were
1
), 37.2 (d, JPC = 25.3 Hz,
=
1
4
2C, Ad-CH ), 37.7 (s, 12C, Ad-CH
2
2
3
C, Ad-C-P), 29.5 (d, JPC = 8.2 Hz, 12C, Ad-CH), 25.4 (d, JPC
1
2
4.4 Hz, 2C, CH -P).
2
Ad
Ad
Synthesis of ( PCP)IrHCl. A mixture of ( PCP-H) (0.5 g,
.71 mmol) and [Ir(COD)Cl] (0.232 g, 0.35 mmol) in toluene
atmosphere. The
solution was cooled and solvent was removed under vacuum to
obtain a dark red crystalline product. A small amount was
recrystallized in n-hexane to obtain X-ray quality crystals.
0
2
(
20 mL) was heated at 70 °C for 3 h under a H
2
1
3
recorded. H NMR (500 MHz, p-xylene-d10): δ 7.26 (d, JHH
=
7.4 Hz, 2H, Ar-H), 7.07 (t, JHH = 7.5 Hz, 1H, Ar-H), 5.81 (d,
3
2
J
HH = 10.3 Hz, 1 H, vinyl-H), 5.53-5.58 (m, 2 H, vinyl-H),
2
Yield: 0.59 g (90%). Anal. Calcd for C48
H
68Br0.3Cl0.7IrP
2
: C,
0.81; H, 7.23; Br, 2.53; Cl, 2.62. Found: C, 61.27; H, 7.13; Br,
3.27 (dvt, JHH = 17.1 Hz, JPH = 3.4 Hz, 2H, CH
2
), 3.12 (dvt,
), 2.16-2.95 (m,
8 H, cyclooctadienyl), 1.58-1.95 (m, 60H, Ad-CH), -43.98 (t,
2
6
2
JHH = 16.9 Hz, JPH = 3.3 Hz, 2H, CH
2
1
.24; Cl, 2.94. H NMR (500 MHz, C
D
6 6
): δ 7.11-7.21 (m, 3H,
), 3.26
2
2
2
Ar-H), 3.32 (dvt, JHH = 13.0 Hz, JPH = 3.5 Hz, 2H, CH
(
2
JPH = 11.2 Hz, 1H, Ir-H), -43.19 (t, JPH = 11.7 Hz, 1H, Ir-H,
2
31 1
dvt, J = 13.0 Hz, JPH = 3.5 Hz, 2H, CH ), 2.17-2.51 (m,
minor isomer). P{ H} NMR (202.3 MHz, p-xylene-d10): δ 56.6
13 1
HH
2
2
2
4H, Ad-CH ), 1.82-1.88 (m, 12H, Ad-CH), 1.52-1.70 (m,
(d, JPH = 10.6 Hz), 55.9 (d, JPH = 11.7 Hz, minor). C{ H}
NMR (125.7 MHz, p-xylene-d10): δ 156.6 (br s), 155.1 (br s),
153.6 (s), 152.2 (s), 148.9 (s), 142.3 (s), 140.9 (s), 138.1 (s), 134.8 (s),
2
2
31
1
4H, Ad-CH ,), -43.16 (t, JPH = 11.25 Hz, 1H, Ir-H). P{ H}
2
2 13 1
6 6
NMR (202.3 MHz, C D ): δ 58.5 (d, JPH = 10.5 Hz). C{ H}
Punji, Benudhar
