Inorganic Chemistry
ARTICLE
’ EXPERIMENTAL SECTION
residue was dissolved in MeCN (3 mL) and cooled to ꢀ35 °C. After 14
days, no crystals had formed. A seed crystal of 12 was added and the
solution cooled to ꢀ35 °C. After 23 days, the mother liquor was
removed via pipet, leaving behind deep red crystals. The crystals were
dissolved in C6H6 (5 mL) and the solution frozen and lyophilized in
vacuo to give crude 12 (0.4712 g, 1.456 mmol, 85%) as a deep red
powder. 1H NMR analysis indicated the presence of 0.1 equiv of
NMo(O-2,6-iPr2C6H3)2(NMe2)(NHMe2) (13) and 0.4 equiv of 2,6-
General Procedures. All reactions were performed in a nitrogen-
filled MBRAUN Labmaster 130 glovebox. 1H NMR spectra were
recorded at 499.909 MHz, 399.967 MHz, or 300.075 MHz on a Varian
Inova 500, Varian Inova 400, Varian MR400, or Varian Inova 300
spectrometer and referenced to the residual protons in CDCl3 (7.26
ppm), bromobenzene-d5 (7.18 ppm), C6D6 (7.16 ppm), CD2Cl2 (5.32
ppm), or toluene-d8 (2.09 ppm). 13C NMR spectra were recorded at
100.724 MHz on a Varian Inova 400 or Varian MR400 spectrometer and
were referenced to naturally abundant 13C nuclei in CDCl3 (77.16
ppm), C6D6 (128.06 ppm), toluene-d8 (125.49), or CD2Cl2 (54.00
ppm). GC/MS data were collected on a Shimadzu GCMS-QP5000 with
a Restek XTI-5 phase column (30 m, 0.25 I.D., 0.25 D. F.). EI-MS data
were collected on a VG (Micromass) 70ꢀ250-S magnetic sector mass
spectrometer. Combustion analyses were performed by Midwest
Microlabs, LLC.
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diisopropylphenol. H NMR (500 MHz, C6D6): δ 7.14 (d, 6H, ArH
(12), 3JHꢀH = 7.5 Hz), 7.02 (d, 0.9H, ArH (HOAr), 3JHꢀH = 7.6 Hz),
6.98 (t, 3H, ArH (12), 3JHꢀH = 7.5 Hz), 6.92 (t, 0.4H, ArH (HOAr),
3JHꢀH = 7.6 Hz), 4.31 (s, 0.4H, OH (HOAr)), 3.94 (s, 0.5H, NCH3
(13)), 3.87 (br s, 6H, CHMe2 (12)), 2.93 (sep, 0.7H, CHMe2 (13),
3JHꢀH = 6.8 Hz), 2.82 (s, 0.5H, NCH3 (13)), 2.39 (sep, 0.7H, CHMe2
3
(HOAr), JHꢀH = 6.1 Hz), 2.02 (s, 3H, NHCH3 (12)), 2.01 (s, 3H,
NHCH3 (12)), 1.37 (d, 1.3H, CHCH3 (13), 3JHꢀH = 6.9 Hz), 1.35 (d,
3
1.3H, CHCH3 (13), JHꢀH = 6.9 Hz), 1.29 (d, 36H, CHCH3 (12),
3
3JHꢀH = 6.8 Hz), 1.14 (d, 4.6H, CHCH3 (HOAr), JHꢀH = 6.8 Hz).
Materials and Methods. All bulk solvents were obtained from
VWR scientific. Benzene and CH2Cl2 were degassed and dried over 4 Å
molecular sieves, and all other solvents used were dried and deoxygenated
13C{1H} NMR (C6D6, 12): δ 161.09, 138.75, 124.65, 123.81, 42.63,
27.75, 24.81. EI/MS [M/Z]þ: 643.8 (NMo(O-2,6-iPr2C6H3)3).
NMo(OSiPh3)2(NMe2)(NHMe2) (14). Solid HOSiPh3 (0.3728 g,
1.349 mmol, 2.1 equiv) was added to a stirring solution of 8 (0.1554
g, 0.642 mmol, 1.0 equiv) in C6H6 (5 mL). The solution immediately
changed to a bright yellow color, which faded as a precipitate formed.
After stirring for 1 h 15 min, pentane (10 mL) was added to the mixture,
and the precipitate was collected by filtration, washed with pentane
(5 mL), and dried in vacuo to yield 14 (0.4778 g, 0.597 mmol, 93%) as a
pale yellow powder. 1H NMR (500 MHz, CD2Cl2): δ 7.71ꢀ7.69 (m,
11H), 7.42ꢀ7.34 (m, 16H), 3.68 (s, 3H, ꢀNCH3), 2.88 (s, 3H,
ꢀNCH3), 2.33 (s, 3H, NHCH3), 2.32 (s, 3H, NHCH3), 2.27 (br s,
1H, NHMe2). 13C{1H} NMR (CD2Cl2): δ 138.94, 135.83, 129.92,
128.26, 62.40, 46.88, 40.90. Anal. Calcd for C40H43MoN3O2Si2: C,
64.07; H, 5.78; N, 5.60. Found: C, 64.02; H, 5.75; N, 5.40.
using the method of Grubbs et al.39 The reagents HOSiPh2 Bu,40 Zr-
t
(NMe2)4,41 NMo(OC(CF3)2Me)3 (3),21 NMo(OC(CF3)3)3(NCMe)
(4),21 NMo(OtBu)3 (6),31 NMo((OC(CF3)Me2)3 (7),13 NMo[N(iPr)-
(3,5-Me2C6H3)]3 (9),33 and NMo[N(tBu)(3,5-Me2C6H3)]3 (10)34 were
all made according to literature procedures. NMR solvents were obtained
from Cambridge Isotope Laboratories and were dried over 4 Å molecular
sieves for at least 24 h. Anisonitrile and 2,6-di-tert-butylphenol were
obtained from Acros. 1-Phenyl-1-butyne was obtained from GFS Chemi-
cals. 1,3,5-Trimethoxybenzene was obtained from Aldrich. 2,6-Diisopro-
pylphenol was obtained from Alfa Aesar. 1,1-Diphenylethanol was
obtained from TCI. Triphenylsilanol was obtained from Gelest. 1-Phen-
yl-1-butyne and 2,6-diisopropylphenol were dried for 24 h using 4 Å
molecular sieves. All other reagents were used as received.
Complex Syntheses. NMo(NMe2)3 (8). In a modification of the
literature procedure,32 solid Zr(NMe2)4 (1.8886 g, 7.06 mmol, 0.85
equiv) was added to a stirring solution of 6 (2.7373 g, 8.31 mmol, 1.0
equiv) in toluene (110 mL). After stirring for 2 h, the solution was
concentrated in vacuo to a volume of ca. 25 mL. Pentane (40 mL) was
added, and the resulting precipitate was collected by vacuum filtration,
washed with pentane, and dried in vacuo to give 8 (1.1844 g, 4.89 mmol,
59%) as a yellow powder. The filtrate was concentrated to dryness; then
the residue was slurried in pentane (20 mL). The mixture was filtered,
and the solid was washed with pentane (3 ꢁ 5 mL) and dried in vacuo to
give a second crop of 8 (0.3690 g, 1.52 mmol, 18%). 1H NMR matched
the literature values.
NMo(OSiPh3)3(NHMe2) (5-NHMe2). A solid mixture of 8 (0.1343 g,
0.555 mmol, 1.0 equiv) and HOSiPh3 (0.4756 g, 1.72 mmol, 3.1 equiv)
was dissolved in THF (10 mL) inside a bomb flask. The flask was placed
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in a 60 °C oil bath, and the reaction solution was stirred for 20 h. H
NMR analysis of an aliquot revealed the presence of a small amount of
remaining 14. Additional HOSiPh3 (0.2760 g, 1.00 mmol, 1.8 equiv) was
added to the reaction solution, which was then stirred at 60 °C for an
1
additional 18 h. H NMR analysis of a second aliquot revealed the
consumption of 14. The reaction solution was pipetted into toluene
(60 mL) with vigorous stirring, but no precipitate formed. The solution
was concentrated in vacuo to a volume of ca. 10 mL, resulting in the
precipitation of a powder. The solid was collected by vacuum filtration,
washed with toluene (3 ꢁ 5 mL) and pentane (10 mL), then dried in
vacuo to yield 5-NHMe2 (0.3363 g, 0.343 mmol, 62%) as a white
powder. 1H NMR analysis revealed the presence of a small amount of
HOSiPh3. The first crop of 15 was dissolved in CH2Cl2 (10 mL), then
Et2O (8 mL) was added and the solution cooled to ꢀ35 °C, resulting in
the precipitation of a white powder. The powder was collected by
vacuum filtration, washed with toluene (2 ꢁ 10 mL) and pentane (2 ꢁ
10 mL), then dried in vacuo to afford 15 (0.2512 g, 0.256 mmol, 46%).
1H NMR analysis of the second crop revealed no improvement in purity
over the first crop of 5-NHMe2. 1H NMR (500 MHz, CD2Cl2): δ 7.58
(br s, 15H, ArH), 7.29 (br s, 8H, ArH), 7.13 (br s, 15H), 2.54 (br s, 1H,
NHMe2), 1.91 (s, 6H, NH(CH3)2). 13C{1H} NMR (CD2Cl2): δ
136.85, 136.06, 130.14, 128.23, 41.77. EI/MS [M/Z]þ: 936.9
(NMo(OSiPh3)3).
NMo(O-2,6-tBu2C6H3)(NMe2)2 (11). Solid 2,6-di-tert-butylphenol
(0.2783 g, 1.349 mmol, 1.1 equiv) was added to a stirring solution of
8 (0.3017 g, 1.246 mmol, 1.0 equiv) in THF (12 mL). After stirring for
5 h 30 min, the volatiles were removed in vacuo; then the residue was
slurried in cold pentane (4 mL) and cooled to ꢀ35 °C. The mixture was
filtered, and the solid was washed with cold pentane (3 ꢁ 1 mL) and
dried in vacuo to give 11 (0.4065 g, 1.008 mmol, 81%) as a pale yellow
1
powder. H NMR (400 MHz, C7D8, ꢀ10 °C): δ 7.36 (d, 2H, ArH,
3JHꢀH = 7.8 Hz), 6.96 (t, 1H, ArH, 3JHꢀH = 7.8 Hz), 3.86 (s, 6H, NCH3),
2.83 (s, 6H, NCH3), 1.52 (s, 18H, C(CH3)3). 13C{1H} NMR (C7D8,
ꢀ10 °C): δ 165.11, 139.05, 137.82, 120.61, 60.67, 44.62, 35.52, 31.58.
Anal. Calcd for C182H33MoN3O: C, 53.59; H, 8.25; N, 10.42. Found: C,
53.21; H, 8.02; N, 10.22.
NMo(O-2,6-iPr2C6H3)3(NHMe2) (12). Complex 8 (0.4150 g, 1.71
mmol, 1.0 equiv) was dissolved in THF (20 mL) inside of a bomb flask.
Neat 2,6-diisopropylphenol (2.16 mL, 8.58 mmol, 5.0 equiv) was added
to the THF solution. The bomb flask was sealed and heated at 60 °C
with stirring for 11 h 30 min. 1H NMR of an aliquot indicated complete
conversion to 12. The solution was concentrated to dryness; then the
NMo(OSiPh3)3 (5). Complex 10 (0.2889 g, 0.452 mmol, 1.0 equiv)
and HOSiPh3 (0.4392 g, 1.589 mmol, 3.5 equiv) were dissolved in
toluene (20 mL) inside a bomb flask. The flask was heated in a 90 °C oil
bath for 5 h 30 min, then cooled. Pentane (25 mL) was added to the
solution with vigorous stirring; then the solution was allowed to settle.
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dx.doi.org/10.1021/ic1024247 |Inorg. Chem. 2011, 50, 5936–5945