Inorganic Chemistry
Article
X-ray Crystallography. Single crystals suitable for X-ray
diffraction were coated with polyisobutylene oil in the glovebox and
transferred to glass fiber with Apiezon N grease before mounting on
the goniometer head of a Bruker APEX Diffractometer (Arizona State
University) equipped with Mo Kα radiation. A hemisphere routine
was used for data collection and determination of the lattice constants.
The space group was identified, and the data was processed using the
Bruker SAINT+ program and corrected for absorption using SADABS.
The structures were solved using direct methods (SHELXS)
completed by subsequent Fourier synthesis and refined by full-matrix,
least-squares procedures on [F2] (SHELXS). Attempts to refine an
inversion twin for 3 resulted in a twin fraction of 0.00166, which was
therefore removed from the final refinement. The solid state structure
of 4 features A-level alerts due to a disordered phenyl ring that has
been modeled as two partially occupied rings with restrictions placed
on thermal parameters and bond distances. For 4, two large electron
density peaks were located within 1.2 Å of Mo but were not modeled
as H atoms due to their proximity to existing Mo−N bonds.
Crystallographic parameters for 3 and 4 are located in Table S1 of the
Supporting Information.
7.2 Hz, 3H, Ph), 5.55 (t, 14.4 Hz, 2H, Ph), 5.01 (d, 14.4 Hz, 2H, Ph),
3.98 (s, 6H, CH3), 3.51 (m, 1H, CH2), 3.28 (t, 7.2 Hz, 1H, CH2), 3.14
(m, 2H, CH2), 2.93 (m, 2H, CH2), 2.81 (m, 2H, CH2), 2.62 (m, 2H,
CH2), 1.88 (m, 2H, CH2). 13C NMR (acetonitrile-d3, 100.49 MHz):
156.9 (CN), 138.4 (Py), 133.6 (Ph), 131.4 (Py), 130.3 (Ph), 129.6
(Ph), 128.7 (Py), 127.2 (Ph), 118.8 (Py), 57.2 (NCH2CH2), 28.1
(PCH2CH2), 26.4 (PCH2CH2), 15.4 (CH3). 31P NMR (acetonitrile-d3,
161.78 MHz): 6.18 (s).
Preparation of (κ6-P,N,N,N,C,P-Ph2PPrPDI)MoH (4). In a nitrogen
filled glovebox, a 20 mL reaction vial was charged with 4.2 g of
mercury and 3 mL of THF. To it, 0.016 g of freshly cut metallic
potassium was added and stirred for 30 min to form clear potassium
amalgam solution. To the solution, 0.078 g (0.081 mmol) of 3 in
10 mL of THF was slowly added and the mixture was allowed to stir at
ambient temperature for 3 d. The resulting green solution was filtered
through Celite, and the solvent was removed in vacuo to yield a green
solid. After washing with pentane and drying, 0.051 g (87%) of a dark
green solid identified as 4 was isolated. Single crystals suitable for
X-ray diffraction were grown from a concentrated toluene solution
at −35 °C. Anal. Calcd for C39H41N3MoP2: Calcd C, 66.00%; H,
Preparation of [(Ph2PPrPDI)MoI(CO)][I] (2). In a nitrogen filled
glovebox, a 20 mL reaction vial was charged with 0.10 g (0.135 mmol)
of 1 and 10 mL of toluene. To the pink solution, 0.034 g (0.135 mmol)
of iodine dissolved in 5 mL of toluene was slowly added while stirring.
A purple solid precipitated within 5 min of stirring. After 5 h, the
reaction mixture was filtered through a sintered frit to remove the
purple solid. After washing with toluene and ether and drying under
vacuum, 0.127 g (0.128 mmol, 95%) of a purple solid identified as
2 was isolated. This complex was recrystallized from a concentrated
acetone/THF solution at −35 °C prior to analysis. Anal. Calcd for
C40H41N3I2OMoP2·C4H8O: C, 49.68; H, 4.64; N, 3.95. Found: C,
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5.82%; N, 5.92%. Found: C, 65.88%; H, 5.57%; N, 5.64%. H NMR
(benzene-d6, 400 MHz): 7.83 (t, 8.4 Hz, 2H, Ar), 7.56 (m, 3H, Ar),
7.49 (t, 8.0 Hz, 2H, Ar), 7.07 (m, 3H, Ar), 7.02 (m, 1H, Ar), 6.62 (m,
1H, Ar), 6.51 (m, 5H, Ar), 5.60 (t, 8.4 Hz, 2H, Ar), 5.49 (m, 2H, Ar),
5.44 (t, 11.9 Hz, 1H, NCH2), 4.85 (d, 10.8 Hz, 1H, NCH2), 4.77 (b,
1H, HCMo), 2.88 (s, 3H, CH3), 2.82 (m, 1H,CH2), 2.62 (m, 2H,
CH2), 2.50 (s, 3H, CH3), 2.27 (m, 1H, CH2), 2.06 (m, 2H, CH2), 1.39
(m, 1H, CH2), 1.18 (m, 1H, CH2), Mo−H peak not located. 13C
NMR (benzene-d6, 100.49 MHz): 147.3 (CN), 145.5 (CN),
139.3 (Ar), 138.7 (d, JCP = 57 Hz, Ar), 134.3 (d, JCP = 33.5 Hz, Ar),
134.0 (d, JCP = 34 Hz, Ar), 132.7 (d, JCP = 2.5 Hz, Ar), 132.6 (d, JCP
9.2 Hz, Ar), 132.2 (Ar), 131.9 (d, JCP = 16.2 Hz, Ar), 131.0 (d, JCP
=
=
1
49.81; H, 4.38; N, 4.30. H NMR (acetone-d6, 400 MHz): 8.46 (d,
8.0 Hz, 1H, Py), 8.33 (d, 8.0 Hz, 1H, Py), 8.01 (t, 8.0 Hz, 1H, Py), 7.77
(t, 6.8 Hz, 2H, Ph), 7.57 (m, 2H, Ph), 7.48 (t, 8.4 Hz, 2H, Ph), 7.36 (m,
2H, Ph), 7.20 (m, 6H, Ph), 6.99 (t, 8.0 Hz, 2H, Ph), 6.92 (t, 8.4 Hz,
2H, Ph), 6.31 (t, 8.8 Hz, 2H, Ph), 4.48 (d, 12.0 Hz, 1H, CH2), 4.24 (d,
12.0 Hz, 1H, CH2), 4.03 (t, 12.0 Hz, 1H, CH2), 3.41 (t, 12.0 Hz, 1H,
CH2), 2.98 (m, 3H, CH2), 2.64 (d, 2.4 Hz, 3H, CH3), 2.57 (m, 1H,
19.9 Hz, Ar), 129.1 (d, JCP = 30.6 Hz, Ar), 117.1 (Ar), 106.5 (Ar),
104.2 (Ar), 57.8 (NCH2), 54.9 (d, JCP = 7.5 Hz, NCHMo), 33.8 (d,
JCP = 47.9 Hz, CH2CH2P), 31.4 (d, JCP = 33.4 Hz, CH2), 30.5 (d, JCP
=
55.7 Hz, CH2), 29.6 (d, JCP = 42.1 Hz, CH2), 17.1 (CH3), 13.2 (CH3).
31P NMR (benzene-d6, 161.78 MHz): 57.94 (d, 97.2 Hz, PPh2), 46.93
(d, 97.2 Hz, PPh2).
CH2), 2.34 (m, 2H, CH2), 2.31 (s, 3H, CH3), 2.19 (m, 2H, CH2). 13
C
Preparation of (κ6-P,N,N,N,C,P-Ph2PPrPDI)Mo(OCOH) (5). In a
nitrogen filled glovebox, a J. Young NMR tube was charged with
0.010 g (0.014 mmol) of 4 dissolved in 0.7 mL of C6D6. The tube was
frozen at 0 °C and degassed, and 0.2 atm of CO2 was added. Within
10 min, formation of a new compound identified as 5 was observed
by multinuclear NMR spectroscopy. Upon removal of excess CO2 and
solvent, 0.009 g (0.012 mmol, 85%) of a green solid identified as 5
was isolated. Anal. Calcd for C40H41N3MoO2P2: Calcd C, 63.74%; H,
NMR (acetone-d6, 100.49 MHz): 238.4 (pseudo t, JCP = 20.5 Hz, CO),
176.6 (Py), 175.8 (Py), 155.4 (CN), 153.8 (CN), 142.8 (d, JCP
=
161.0, Ph), 135.4 (d, JCP = 15.0 Hz, Ph), 133.7 (d, JCP = 13.8 Hz, Ph),
133.5 (d, JCP = 10.8 Hz, Ph), 133.2 (Py), 132.3 (d, JCP = 26.2 Hz, Ph),
130.8 (d, JCP = 13.3 Hz, Ph), 130.5 (d, JCP = 15.2 Hz, Ph), 130.5 (d,
JCP = 30.3 Hz, Ph), 129.1 (d, JCP = 14.7 Hz, Ph), 128.2 (Py), 128.1 (d,
JCP = 7.9 Hz, Ph), 127.2 (Py), 61.4 (NCH2), 59.3 (NCH2), 28.2 (d,
JCP = 46.6 Hz, CH2CH2P), 26.9 (d, JCP = 3.9 Hz, CH2CH2P), 26.1 (d,
JCP = 5.2 Hz, CH2CH2P), 25.9 (d, JCP = 36.7 Hz, CH2CH2P), 17.3
(CH3), 17.1 (t, JCP = 4.0 Hz, CH3). 31P NMR (acetone-d6, 161.78
MHz): 39.62 (d, JPP = 13.7 Hz), 39.22 (d, JPP = 13.7 Hz). IR (KBr
pellet): νCO = 1826 cm−1.
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5.48%; N, 5.57%. Found: C, 63.51%, H, 5.42%, N, 5.28%. H NMR
(benzene-d6, 400 MHz): 9.14 (s, 1H, CHO), 7.25 (m, 4H, Ar), 7.12
(m, 5H, Ar), 7.02 (t, 7.2 Hz, 3H, Ar), 6.90 (t, 7.6 Hz, 1H, Ar), 6.59 (t,
7.6 Hz, 2H, Ar), 6.43 (t, 7.6 Hz, 4H, Ar), 6.26 (t, 12.0 Hz, 1H, NCH2),
5.62 (s, 1H, NCHMo), 5.56 (t, 7.8 Hz, 2H, Ar), 5.25 (t, 8.4 Hz, 2H,
Ar), 4.55 (d, 12.0 Hz, 1H, NCH2), 3.34 (m, 2H, CH2), 2.80 (m, 1H,
CH2), 2.73 (s, 3H, CH3), 2.47 (s, 3H, CH3), 2.04 (m, 1H, CH2), 1.87
(m, 1H, CH2), 1.76 (t, 14.4 Hz, 1H, CH2), 1.39 (m, 3H, CH2), 0.74
(m, 1H, CH2). 13C NMR (benzene-d6, 100.49 MHz): 169.7
(MoOCOH), 148.1 (CN), 148.1 (CN), 144.6 (Ar), 132.8 (d,
JCP = 17.8 Hz, Ar), 132.2 (d, JCP = 20.0 Hz, Ar), 131.3 (d, JCP = 17.2
Hz, Ar), 130.9 (d, JCP = 18.9 Hz, Ar), 129.4 (Ar), 128.6 (d, JCP = 7.6
Hz, Ar), 128.5 (d, JCP = 10.0 Hz, Ar), 127.6 (d, JCP = 10.0 Hz, Ar),
117.5 (Ar), 106.8 (Ar), 106.1 (Ar), 57.4 (NHCMo), 50.2 (NCH2),
30.5 (d, JCP = 14.9 Hz, CH2), 28.8 (CH2), 23.9 (d, JCP = 30.6 Hz,
CH2), 20.9 (d, JCP = 34.2 Hz, CH2), 16.6 (CH3), 13.5 (CH3). 31P
NMR (benzene-d6, 161.78 MHz): 43.80 (d, 186.2 Hz, PPh2), 28.10 (d,
186.2 Hz, PPh2). IR (KBr pellet): νOCOH = 1625 cm−1.
Preparation of [(Ph2PPrPDI)MoI][I] (3). In a nitrogen filled
glovebox, a 100 mL thick-walled reaction bomb was charged with
0.080 g (0.080 mmol) of 2 dissolved in 20 mL of THF and a magnetic
stir bar. The sealed bomb was frozen in liquid nitrogen and degassed
on a Schlenk line before being refluxed at 100 °C in a preheated oil
bath. A brownish-amber solid began to precipitate within 2 h of
stirring. After 12 h, the reaction mixture was allowed to cool at room
temperature and degassed on the Schlenk line. Once the liberated CO
gas was removed, the reaction was allowed to reflux for 24 h at 100 °C
to ensure reaction completion. After another CO removal step, the
bomb was brought inside the glovebox and an amber solid was isolated
on top of a sintered frit. The product was washed with THF, ether,
and pentane and dried under vacuum to yield 0.053 g (0.055 mmol,
68%) of an amber solid identified as 3. Single crystals suitable for X-ray
diffraction were grown from a concentrated solution in acetone/THF
at −35 °C. Anal. Calcd for C39H41N3I2MoP2: C, 48.61; H, 4.29; N,
Stoichiometric Reduction of CO2 Using 4. In the glovebox,
a 20 mL scintillation vial containing 0.014 mmol of 4 was charged with
pinacolborane (0.28 mmol) in 0.7 mL of benzene-d6. The mixture
was transferred into a J. Young NMR tube and sealed under nitrogen.
After degassing the tube, 0.2 atm of CO2 gas was added to the frozen
1
4.36. Found: C, 48.35; H, 4.13; N, 4.13. H NMR (acetonitrile-d3,
400 MHz): 7.46 (t, 8.0 Hz, 1H, Py), 7.30 (m, 7H, Ph), 6.92 (t, 7.2 Hz,
2H, Ph), 6.72 (t, 7.6 Hz, 4H, Ph), 6.45 (d, 8.0 Hz, 2H, Py), 6.01 (d,
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Inorg. Chem. 2015, 54, 7506−7515