Organometallics
Article
and the remaining Me SiCl. The residue was further distilled under air
29.8 mg (74%). Anal. Calcd. for C H F MoN O (818.37 g/mol):
C, 32.29%; H, 2.96%; N, 3.42%. Found: C, 32.58%; H, 3.11%; N,
3.37%.
3
22 24 18
2
4
(
ambient pressure, oil bath at 140−170 °C, static water for cooling;
bp 110 °C) to yield 17.85 g (129 mmol, 44%) of 2,2,5,5-
tetramethylhex-3-yne as a colorless liquid. The product was degassed
and dried over 4 Å MS prior to synthetic use. The observed boiling
point is consistent with literature value (111.9 °C at 746 Torr, ref 19):
Mo(O)(CH-t-Bu)(OR ) (TMEDA) (2b). A round-bottom flask was
F9 2
charged with Mo(C-t-Bu)(OR ) (1.08 g, 1.24 mmol), TMEDA
F9
3
(465 μL, 3.10 mmol, 2.5 equiv), and Et O (50 mL) to form a yellow
2
1
20
H NMR (400 MHz, C D ) δ 1.23 (s).
clear mixture. Water (10 wt % in THF, 248 μL, 1.24 mmol, 1.0 equiv)
was added dropwise at room temperature under vigorous stirring to
form a dark orange mixture. The mixture was stirred for 20 h at room
temperature and turned dark yellow. The volatiles were removed
under vacuum. The solid residue was triturated with pentane (20 mL)
and collected by filtration to yield 650 mg of pure product as a yellow
powder. The filtrate was concentrated to 5 mL and chilled at −20 °C
for a few hours to yield a second crop of yellow solid (92 mg). Total
6
6
Me SiOR . A Schlenk storage flask was charged with NaOR
3
F9
F9
(
4.75 g, 18.4 mmol) and Et O (20 mL). A Et O solution (5 mL) of
2
2
Me SiCl (2.00 g, 18.4 mmol) was added. The mixture was stirred at
3
room temperature for 2 days and then filtered. The filtrate was
fractionally distilled under nitrogen (1 atm), and the fraction at ∼85
°
C was condensed and collected as a colorless liquid. Yield: 1.74 g
11
1
(
30%). The NMR data are in line with literature report: H NMR
500 MHz, CD Cl ) δ 0.28 (s); F NMR (470 MHz, CD Cl ) δ
1
9
(
yield: 742 mg (78%). Anal. Calcd for C19H F18MoN O (768.35 g/
26 2 3
2
2
2
2
−
74.0.
mol): C, 29.70%; H, 3.41%; N, 3.65%. Found: C, 29.53%; H, 3.40%;
N, 3.56%. %. Single crystal sample of 2b for X-ray analysis was
obtained from diffusion of pentane into a solution of diethyl ether at
−20 °C.
Mo(C-t-Bu)(OR ) . A Schlenk storage flask was charged with
F9 3
Mo(CMesityl)(OR ) (20.2 g, 21.7 mmol), C H (450 mL), and t-
F9
3
6
6
BuCC-t-Bu (15.0 g, 108 mmol, 5.0 equiv). The flask was sealed,
and the mixture was stirred at 100 °C for 3 days to afford a pale red
clear mixture. The mixture was cooled to room temperature, and
formation of a yellow flaky precipitate was complete within a few
hours. The flask was transferred into a glovebox, and the solid was
collected by filtration. The filtrate was concentrated under vacuum to
Mo(O)(CHMesityl)(ORF9
Mo(CMesityl)(ORF9 (50.0 mg, 53.6 μmol), TMEDA (20.1 μL, 134
μmol, 2.5 equiv), and Et O (2 mL) to form a red mixture. Water (10
) (TMEDA) (2c). A vial was charged with
2
)
3
2
wt % in THF, 10.7 μL, 53.6 μmol, 1.0 equiv) was added in one
portion under vigorous stirring to form a dark yellow mixture. The
mixture was stirred for 20 h at room temperature and turned dark red.
The mixture was filtered through a pad of Celite. The red filtrate was
concentrated to 1 mL under vacuum and treated with pentane (5
mL). The mixture was stored at −20 °C overnight to give pure
product as an orange microcrystalline solid, which was collected by
filtration, washed with cold pentane, and dried under vacuum. Yield:
2
00 mL, and the resulting yellow precipitate was collected by
filtration. The combined solid was extracted with pentane (200 mL).
The extract was filtered through a pad of Celite and concentrated to
dryness to yield a crude product, which was recrystallized in pentane
at −20 °C to afford 16.20 g (86%, 3 crops) of Mo(C-t-Bu)(OR ) as
yellow flakes. Alternatively, the crude product can be purified by
sublimation under high vacuum (35 °C, 20 mTorr). Anal. Calcd for
C H F MoO (870.16 g/mol): C, 23.47%; H, 1.04%. Found: C,
F9
3
28.3 mg (64%). Anal. Calcd for C24H F18MoN O (830.42 g/mol):
28 2 3
C, 34.71%; H, 3.40%; N, 3.37%. Found: C, 34.95%; H, 3.55%; N,
3.37%.
1
7
9
27
3
2
3.59%; H, 1.07%.
Mo(O)(CHAr )(OR ) (THF) (1(THF) ). A vial was charged with
Mo(O)(CH-t-Bu)(ORF9
(300 mg, 390 μmol) and CH
solution. A CH Cl solution (1 mL) of 2,2′-bipyridyl (62.0 mg, 396
)
2
(bipy) (2d). A vial was charged with 2b
p
F9 2
2
2
Mo(CAr )(OR ) (DME) (500 mg, 495 μmol) and THF (8 mL,
2
Cl (3 mL) to form a dark yellow
2
p
F9 3
[
Mo] = 62 mM) to form a green solution. Et N (3.5 μL, 25 μmol, 5
2
2
3
mol %) was added, and the mixture was chilled at −20 °C for 10 min.
Water (10 wt % in THF, 99 μL, 495 μmol, 1.00 equiv) was quickly
injected into the vigorously stirred mixture, and the mixture was
stirred and allowed to warm to room temperature over 30 min. The
volatiles were removed under vacuum to yield an orange solid residue.
The residue was extracted in THF (1 mL)/pentane (20 mL), and the
μmol, 1.02 equiv) was added, and the mixture was stirred at room
temperature for 15 min. The mixture was concentrated under vacuum
to 1 mL and treated with pentane (8 mL). The mixture was chilled at
−20 °C for 1 h, and the yellow precipitate was collected by filtration,
washed with cold pentane, and dried under vacuum. Yield: 230 mg
(73%). The compound exists as a 10:1 equilibrium mixture of two
clear liquid was stored at −20 °C to yield a mixture of red 1(THF)
syn-alkylidene isomers at room temperature in CD
Calcd for C23 (808.33 g/mol): C, 34.18%; H, 2.24%;
N, 3.47%. Found: C, 34.09%; H, 2.08%; N, 3.54%.
Mo(O)(CHAr )(OHMT) (3a). A vial was charged with 1(THF)
(200 mg, 236 μmol) and C H (15 mL, [Mo] = 16 mM). LiOHMT
2 2
Cl solvent. Anal.
2
and green Mo(CAr )(OR ) (THF) crystals. The solid mixture was
H F18MoN O
18 2 3
p
F9
3
2
separated from the mother liquor and dissolved in DME (10 mL).
The mixture was concentrated to dryness, and the residue was
dissolved in CH Cl (10 mL). The mixture was stored at −20 °C to
p
2
2
2
2
6
6
give purple needles of unreacted Mo(CAr )(OR ) (DME) (113 mg,
(196 mg, 583 μmol, 2.5 equiv) was added in one portion, and the
mixture was stirred at room temperature for 24 h to yield a purple
suspension. The mixture was filtered through a pad of Celite to
remove the white precipitate. The filtrate was loaded into a Schlenk
bomb, and the volatiles were removed under Schlenk vacuum at 60
°C. The purple residue was extracted with pentane (20 mL), and the
extract was stored at −20 °C to yield purple crystals and a small
p
F9 3
2
3%), which was collected by filtration, washed with cold CH Cl ,
2 2
and dried under vacuum. The mother liquor was concentrated to
dryness, and the residue was dissolved with THF (10 mL). The
volatiles were concentrated to dryness. The residue was extracted with
THF (1 mL)/pentane (20 mL), and the clear liquid was separated
from trace insoluble impurities by filtration and stored at −20 °C to
yield pure product as red crystals (198 mg, 2 crops, 47%). Anal. Calcd
for C H F MoO (846.37 g/mol): C, 34.06%; H, 2.86%. Found: C,
amount of colorless crystals (LiOR ). The solid was agitated in
F9
pentane, and the purple crystals were isolated by swiftly decanting off
the pentane suspension of colorless crystals. The remaining purple
solid was recrystallized in C H (0.3 mL)/pentane (5 mL) at −20 °C
24
24 18
6
3
4.22%; H, 2.73%. Single crystal sample of 1(THF) for X-ray analysis
2
was obtained from diffusion of pentane into a THF solution at −20
C.
Mo(O)(CHAr )(OR ) (TMEDA) (2a). A vial was charged with
6
6
°
to give pure product as purple needles (138 mg, 66%). The NMR
4b
data are identical to those reported in the literature.
Mo(O)(CHAr )(OTPP) (3b). A flask was charged with 1(THF)
2
p
F9 2
Mo(CAr )(OR ) (DME) (50.0 mg, 49.5 μmol), TMEDA (18.6 μL,
p
F9
3
p
2
1
24 μmol, 2.5 equiv), and Et O (2 mL) to form a pale yellow mixture.
(400 mg, 473 μmol) and Et O (30 mL). NaOTPP (containing 1.3
2
2
Water (10 wt % in THF, 9.9 μL, 49 μmol, 1.0 equiv) was added in
one portion under vigorous stirring to form a red mixture, which
turned dark red within a few minutes. The mixture was stirred for 20
h at room temperature and then filtered through a pad of Celite. The
red filtrate was concentrated to 1 mL under vacuum and treated with
pentane (5 mL). The mixture was stored at −20 °C overnight to give
pure product as a red microcrystalline solid, which was collected by
filtration, washed with cold pentane, and dried under vacuum. Yield:
THF per Na, 515 mg, 992 μmol, 2.1 equiv) was added in one portion,
and the mixture was stirred at room temperature for 1 h to yield a
dark red suspension. The mixture was filtered through a pad of Celite
on a frit, and CH Cl (100 mL) was added to the frit in portions to
2
2
elute the dark red component. The filtrate was concentrated to
dryness to yield a red solid residue. The residue was stirred in MeCN
(15 mL) for 2 h to yield a pinkish powdery precipitate, which was
collected by filtration. The solid was stirred in toluene (4 mL) for 30
E
Organometallics XXXX, XXX, XXX−XXX