Organometallics
Article
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Agilent Cary 60 UV−vis spectrophotometer using a 1 cm two-window
quartz spectrophotometer cell sealed with a screw cap purchased from
Hellma Analytics (117.100-QS). UV−vis spectra used for kinetic data
were measured with an Agilent Cary 60 UV−vis spectrophotometer
with a fiber optic coupler (Agilent) and a fiber optic dip probe
purchased from Hellma Analytics (661.202-UV, 10 mm). Air-sensitive
solutions were prepared in a glovebox (N2 filled, Korea Kiyon) and
reactions carried out in custom-made Schlenk tubes designed for the
dip probe. Infrared spectra were recorded in KBr pellets with a Bruker
VECTOR 33 instrument. Frequencies are given in reciprocal
centimeters (cm−1), and only selected absorbances are reported.
Synthesis of (PPP)Ni(SPh) (1a). To a suspension of NaSPh (33
mg, 0.29 mmol) in 3 mL of THF was added a solution of (PPP)NiCl
(101 mg, 0.198 mmol) in 5 mL of THF, causing an immediate color
change from violet to brown. The reaction mixture was stirred for 2 h
at room temperature, and all volatiles were removed under vacuum.
After the residue was dissolved in benzene, a brown solution was
filtered through Celite and the volatiles were removed under vacuum.
The resulting product (PPP)Ni(SPh) (1a; 103 mg, 0.175 mmol,
88.4%) was isolated as a brown solid after washing with pentane and
under vacuum. H NMR (400 MHz, C6D6): δ 8.43−8.40 (m, 2H),
7.62 (d, J = 7.7 Hz, 2H), 7.24−7.13 (m, 4H), 7.05−6.92 (m, 5H),
2.17−2.07 (m, 4H), 1.30 (q, J = 8.0 Hz, 6H), 0.95 (q, J = 8.0 Hz, 6H),
0.89−0.80 (m, 12H). 13C NMR (101 MHz, C6D6): δ 206.4 (s, NiCO),
184.5 (s, free CO), 149.8−149.1 (m, Ar-C), 145.3−144.5 (m, Ar-C),
135.3 (d, J = 4.0 Hz, Ar-C), 131.0 (t, J = 7.0 Hz, Ar-C), 129.6 (s, Ar-
C), 129.5 (s, Ar-C), 128.9 (s, Ar-C), 128.7 (s, Ar-C), 29.1 (t, J = 14.1
Hz, CH(CH3)2), 26.4 (dt, J = 19.1 Hz, 5.0 Hz, CH(CH3)2), 20.2−20.0
(m, CH(CH3)2), 19.6 (t, J = 4.0 Hz, CH(CH3)2), 18.9 (s, CH(CH3)2).
31P NMR (162 MHz, C6D6): δ 92.35 (t, J = 80.2 Hz, 1P), 68.66 (d, J =
79.4 Hz, 2P). UV−vis [THF, nm (L mol−1 cm−1)]: 480 (2700). IR
(KBr pellet, cm−1): νCO 1917, νAr 1580. Anal. Calcd for
C31H41NiOP3S: C, 60.71; H, 6.74; S, 5.23. Found: C, 60.71; H,
6.69; S, 4.87. Orange crystals suitable for X-ray diffraction were
obtained by evaporation of the saturated acetonitrile solution of 2a.
Synthesis of (PPSC6H4NMe2P)Ni(CO) (2b). In a 25 mL Schlenk
tube, a solution of 1b (43 mg, 0.068 mmol) in 10 mL of MeCN/
toluene (5/1) was degassed by three freeze−pump−thaw cycles on the
Schlenk line and then exposed to CO(g) at ambient pressure. The
reaction mixture was stirred for 1 h at room temperature, causing a
color change from brownish dark green to orange. After the volatiles
were removed, the resulting solid was washed with pentane and dried
under vacuum. The product (PPSC6H4NMe2P)Ni(CO) (2b; 37 mg,
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drying under vacuum. H NMR (400 MHz, C6D6): δ 8.13 (d, J = 7.9
Hz, 2H), 7.88 (dd, J = 8.1, 3.0 Hz, 2H), 7.11 (t, J = 7.4 Hz, 2H), 7.06
(t, J = 7.6 Hz, 2H), 7.01−6.89 (m, 5H), 2.29−2.20 (m, 4H), 1.38 (q, J
= 7.8 Hz, 12H), 0.99 (q, J = 7.1 Hz, 12H). 13C NMR (151 MHz,
C6D6): δ 156.3−155.8 (m, Ar-C), 149.6 (t, J = 4.5 Hz, Ar-C), 136.7−
136.3 (m, Ar-C), 134.9 (s, Ar-C), 130.9 (d, J = 2.6 Hz, Ar-C), 130.8 (s,
Ar-C), 128.8 (q, J = 9.0 Hz, Ar-C), 128.4 (s, Ar-C), 125.3 (s, Ar-C),
122.6 (s, Ar-C), 26.1 (t, J = 11.3 Hz, CH(CH3)2), 19.0 (s, CH(CH3)2),
18.0 (s, CH(CH3)2). 31P NMR (162 MHz, C6D6): δ 128.12 (t, J = 5.7
Hz, 1P), 53.76 (d, J = 4.9 Hz, 2P). UV−vis [THF, nm (L mol−1
cm−1)]: 430 (4200), 555 (2000). IR (KBr pellet, cm−1): νAr 1577.
Anal. Calcd for C30H41NiP3S·1/6(pentane): C, 62.00; H, 7.26; S, 5.37.
Found: C, 61.64; H, 7.25; S, 4.96.
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0.0056 mmol, 82%) was isolated as an orange solid. H NMR (400
MHz, C6D6): δ 8.51 (t, J = 5.6 Hz, 2H), 7.56 (d, J = 8.6 Hz, 2H),
7.23−7.16 (m, 4H), 7.03 (t, J = 6.6 Hz, 2H), 6.44 (d, J = 8.2 Hz, 2H),
2.36 (s, 6H), 2.17−2.10 (m, 4H), 1.33 (dd, J = 15.2, 6.6 Hz, 6H), 1.03
(dd, J = 14.2, 7.0 Hz, 6H), 0.88−0.80 (m, 12H). 13C NMR (101 MHz,
C6D6): δ 206.8 (td, J = 6.2, 2.2 Hz, NiCO), 150.8 (d, J = 1.8 Hz, Ar-
C), 150.0−149.4 (m, Ar-C), 145.7−144.8 (m, Ar-C), 137.1 (d, J = 3.5
Hz, Ar-C), 131.0 (t, J = 6.1 Hz, Ar-C), 129.5 (dd, J = 4.0, 9.1 Hz, Ar-
C), 128.8 (d, J = 1.9 Hz, Ar-C), 119.9 (d, J = 5.4 Hz, Ar-C), 113.1 (d, J
= 0.9 Hz, Ar-C), 40.0 (s, N(CH3)2), 29.6 (td, J = 12.5, 2.7 Hz,
CH(CH3)2), 26.2 (dt, J = 19.4, 5.1 Hz, CH(CH3)2), 20.3−20.2 (m,
CH(CH3)2), 19.7 (td, J = 4.0, 1.9 Hz, CH(CH3)2), 19.0 (t, J = 2.8 Hz,
CH(CH3)2). 31P NMR (162 MHz, C6D6): δ 93.75 (t, J = 73.7 Hz, 1P),
69.34 (d, J = 74.5 Hz, 2P). UV−vis [THF, nm (L mol−1 cm−1)]: 475
(2400). IR (KBr pellet, cm−1): νCO 1919, νAr 1593, νCN 1503. Anal.
Calcd for C33H46NNiOP3S: C, 60.38; H, 7.06; N, 2.13; S, 4.88. Found:
C, 60.04; H, 7.17; N, 2.16; S, 4.74. Orange crystals suitable for X-ray
diffraction were obtained by evaporation of a saturated pentane
solution of 2b.
Kinetic Experiment. A solution of 1a (10 mL, 0.18 mM in
MeCN/toluene (4/1)) was added to a Schlenk tube, and an initial
UV−vis spectrum (250 nm < λ < 1100 nm) was measured. After
CO(g) was bubbled through a solution with a needle connected to the
Schlenk line, spectra were collected with 18 s intervals over the course
of 7 min. The time-stacked UV−vis spectra (Figure S26a in the
Supporting Information) show the consumption of 1a (λmax 425, 545
nm) and an increase in absorbance of 2a (λmax 480 nm) indicating the
formation of 2a. Isosbestic points were shown at λ 375, 390, and 490
nm. A solution of 1b (10 mL, 0.2 mM in MeCN/toluene (4/1)) was
added to a Schlenk tube, and an initial UV−vis spectrum (250 nm < λ
< 1100 nm) was measured. After CO(g) was bubbled for 3 s through a
solution with a needle connected to the Schlenk line, spectra were
collected with 18 s intervals over the course of 15 min. The time-
stacked UV−vis spectra (Figure S26b) show the consumption of 1b
(λmax 450, 570 nm) and an increase in absorbance of 2b (λmax 470 nm)
indicating the formation of 2b. Absorbance at λmax 545 nm for reaction
of 1a and λmax 570 nm for 1b was used for plotting the absorbance vs
Synthesis of (PPP)Ni(SC6H4NMe2) (1b). To a suspension of
NaSC6H4NMe2 (22 mg, 0.13 mmol) in 3 mL of THF was added a
solution of (PPP)NiCl (54 mg, 0.11 mmol) in 5 mL of THF, causing
an immediate color change from violet to brownish dark green. The
reaction mixture was stirred for 2 h at room temperature, and all
volatiles were removed under vacuum. After the residue was dissolved
in diethyl ether, a brown solution was filtered through Celite and the
volatiles were removed under vacuum. The product (PPP)Ni-
(SC6H4NMe2) (1b; 65 mg, 0.10 mmol, 94%) was isolated as a
brownish dark green solid after washing with pentane and drying
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under vacuum. H NMR (400 MHz, C6D6): δ 7.99 (d, J = 8.4 Hz,
2H), 7.92 (d, J = 6.0 Hz, 2H), 7.14−7.10 (m, 2H), 7.04−7.01 (m,
2H), 6.96−6.90 (m, 2H), 6.54 (d, J = 8.4 Hz, 2H), 2.52 (s, 6H), 2.31−
2.23 (m, 4H), 1.45 (q, J = 7.8 Hz, 12H), 1.02 (q, J = 7.0 Hz, 12H). 13C
NMR (101 MHz, C6D6): δ 156.8−156.1 (m, Ar-C), 147.9 (s, Ar-C),
137.1−137.6 (m, Ar-C), 135.9 (s, Ar-C), 134.0−134.9 (m, Ar-C),
131.0 (s, Ar-C), 130.7 (s, Ar-C), 129.0−128.7 (m, Ar-C), 125.1 (s, Ar-
C), 113.4 (s, Ar-C), 41.0 (s, N(CH3)2), 25.9 (t, J = 11.2 Hz,
CH(CH3)2), 19.2 (s, CH(CH3)2), 18.1 (s, CH(CH3)2). 31P NMR
(162 MHz, C6D6): δ 128.84 (t, J = 5.7 Hz, 1P), 54.42 (d, J = 4.9 Hz,
2P). UV−vis [THF, nm (L mol−1 cm−1)]: 455 (6700), 585 (3100). IR
(KBr pellet, cm−1): νAr 1591, νCN 1490. Anal. Calcd for
C32H46NNiP3S: C, 61.16; H, 7.38; N, 2.23; S, 5.10. Found: C,
60.82; H, 7.42; N, 2.24; S, 5.11. Dark brown crystals suitable for X-ray
diffraction were obtained by cooling a saturated diethyl ether solution
of 1b to −35 °C.
Synthesis of (PPSPhP)Ni(CO) (2a). In a 25 mL Schlenk tube, a
solution of 1a (180 mg, 0.308 mmol) in 10 mL of MeCN was
degassed by two freeze−pump−thaw cycles on the Schlenk line and
then exposed to CO(g) at ambient pressure. The reaction mixture was
stirred for 1 h at room temperature, resulting in precipitation of an
orange solid. The precipitate was isolated and washed with pentane.
The resulting product (PPSPhP)Ni(CO) (2a; 104 mg, 0.169 mmol,
55.0%) was obtained as an orange crystalline solid after drying under
vacuum. After all volatiles were removed from the orange MeCN
solution, an additional portion of 2a (52 mg, 0.084 mmol, 27%) was
isolated as an orange solid after washing with pentane and drying
Reaction of 1a with CO(g) in C6D6. In an NMR tube equipped
with a J. Young valve, the dark brown solution of 1a (5 mg, 0.01
mmol) in 0.5 mL of C6D6 was taken out of the drybox and degassed by
three freeze−pump−thaw cycles on the Schlenk line. After CO(g) was
added, the reaction mixture was heated to 60 °C and the reaction was
monitored for 1 month by 31P NMR spectroscopy.
Reaction of 1b with CO(g) in C6D6. In an NMR tube equipped
with a J. Young valve, a greenish dark brown solution of 1b (10 mg,
0.016 mmol) in 0.5 mL of C6D6 was taken out of the drybox and
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Organometallics XXXX, XXX, XXX−XXX