Journal of the American Chemical Society
Page 6 of 8
Additional experimental procedures, crystallographic data, and spectral
characterization are available free of charge via the Internet at
sistently preparing pure product). To the resulting residue was
added 8 mL of pentane and the mixture was stirred for 15 min,
allowed to settle, and was then filtered through a pipette equipped
with a glass fiber filter into a 20 mL scintillation vial. The filtrate
was placed in the -30 °C freezer for 12 h, yielding 1.44 g of 4 (66%)
as red/orange crystals, which were isolated by decantation and
dried under vacuum. The supernatant was dried under vacuum and
the residue was recrystallized in an identical fashion using 2 mL of
pentane to yield an additional 0.42 g of 4, bringing the total yield to
1
2
3
4
5
6
7
8
AUTHOR INFORMATION
Corresponding Author
* E-mail: tdtilley@berkeley.edu
Notes
The authors declare no competing financial interests.
1
1.86 g (85%). H NMR (400 MHz, C6D6, 20 ºC) δ 64.15, 51.33,
9
36.43, -54.92.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACKNOWLEDGMENT
K[(η6-IPr)Fe–N(SiMe3)DIPP] (5). To a 20 mL scintillation
vial was added 1 (0.200 g, 0.289 mmol) and 6 mL of Et2O, to give a
red solution. To the stirred solution was added potassium graphite
(0.058 g, 0.43 mmol, 1.5 equiv), causing an immediate color
change from red to dark red/orange along with the formation of
black graphite. The mixture was stirred for 30 min, then stirring was
ceased and the mixture was allowed to settle. The mixture was then
filtered through a pipette fitted with a glass fiber filter into a 20 mL
scintillation vial and the volatile components were removed under
vacuum. The resulting residue was dissolved in 5 mL of toluene and
the solution was layered with 15 mL of pentane and placed in a -30
°C freezer for 12 h, yielding 0.142 g of 5 (68%) as long, dark red
needle-shaped crystals which were isolated by decantation and
dried under vacuum. The supernatant was dried under vacuum,
and recrystallized and isolated in an identical fashion using 2 mL of
toluene and 10 mL of pentane, yielding an additional 0.041 g of 5,
bringing the total yield to 0.183 g (87%). Note: compound 5 dis-
solves rather slowly in toluene, so several minutes of agitation are
We gratefully acknowledge funding from the National Science Founda-
tion for this work under grant no. CHE-1265674. We also acknowledge
the National Institutes of Health for funding of the ChexRay X-ray
crystallographic facility (College of Chemistry, University of Califor-
nia, Berkeley) under grant no. S10-RR027172 and for funding of the
Berkeley College of Chemistry NMR facility under grant no.
SRR023679A. We acknowledge Prof. C. Chang for use of his laborato-
ry's Mossbauer spectrometer and Dr. T. Kent (See Co.) for helpful
discussions. We also acknowledge funding from the Development and
Promotion of Science and Technology scholarship provided by the
government of Thailand.
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1
required to dissolve the residue for recrystallization. The H NMR
spectrum of 5 in benzene-d6 varies greatly with concentration,
which we attribute to the presence of various oligomers capped by
benzene (see X-ray crystal structure for polymeric structure of 5).
μeff = 3.9 μB (C6D6, 20°C, Evans’s method). Anal. Calcd. for
C42H62FeKN3Si: C, 68.91%; H, 8.54%; N, 5.74%. Found: C,
69.24%; H, 8.45%; N, 6.12%. Crystals suitable for single crystal X-
ray diffraction studies were obtained from the workup described
above.
IPr–Fe(CNXyl)–N(SiMe3)DIPP (6). To a 20 mL scintillation
vial was added 1 (0.108 g, 0.156 mmol) and 2 mL of Et2O, to form
a red solution. To this solution was added a solution of xylyl isocy-
anide (0.0205 g, 0.156 mmol) in 2 mL of Et2O causing an immedi-
ate color change from red to very dark orange. The volatile compo-
nents of the mixture were immediately removed under vacuum and
the resulting residue was dissolved in 2 mL of Et2O and layered
with 8 mL of HMDSO. This mixture was placed in the -30 °C
freezer for 12 h, yielding 0.104 g of 6 (81%) as dark orange crystals
which were isolated by decantation and dried under vacuum. The
1H NMR spectrum of 6 contains numerous broad and overlapping
peaks from 4-7.25 ppm, so assigning shifts to individual peaks and
integration of these peaks is not possible. All clearly visible charac-
1
teristic peaks of 6: H NMR (500 MHz, C6D6, 20 °C) δ 63.57,
48.62, 28.07, 12.97, 8.54, 4.55, 3.05, -8.50, -24.05, -54.11. μeff = 4.1
μB (C6D6, 20°C, Evans’s method). Anal. Calcd. for C51H71FeN4Si:
C, 74.33%; H, 8.68%; N, 6.80%. Found: C, 74.01%; H, 8.88%; N,
6.85%. Crystals suitable for single crystal X-ray diffraction studies
were obtained from the workup described above.
(10) Lipschutz, M. I.; Tilley, T. D. Organometallics 2014, 33, 5566.
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Guard, L. M.; Hazari, N.; Lin, P.-H.; Pokhrel, R.; Takese, M. K. Chem. Eur.
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Ciello, S. A.; Iluc, V. M.; Hillhouse, G. L. J. Am. Chem.
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