Inorganic Chemistry
Article
antiferromagnetic broken symmetry solution with Ms = 0. The
localized orbitals were calculated using the Pipek−Mezey scheme.
crystals. Yield: 590 mg (81%). mp: 120 °C. IR (ATR, 298 K, in
42
−1
cm ): 690 (s), 710 (s), 727 (m), 747 (s), 782 (m), 829 (vs), 875
X-ray Crystal Structure Determination. Suitable single crystals
of 2a−2c, 3, 4, and 6 were coated with perfluoropolyether (PFO-
XR75), picked up with nylon loops, and immediately mounted in the
nitrogen cold stream of the diffractometers at 100 K. A Bruker Nonius
KappaCCD diffractometer with a Mo-target rotating-anode X-ray
source and Incoatec Helios focusing multilayer optics and a Bruker
Kappa Mach3 APEX-II diffractometer with a Bruker IμS and Incoatec
Helios mirror was used (Mo Kα radiation; λ = 0.71073 Å). Final cell
constants were obtained from least-squares fits of setting angles of
several thousand strong reflections. Intensity data were corrected for
(m), 958 (s), 1098 (vw), 1239 (m), 1437 (w), 2893 (vw), 2945 (vw).
1
H NMR (C D , 298 K, in ppm): δ 10.94 (6H, br, o/m-CH), 7.69
6
6
(6H, br, o/m-CH), 5.19 (3H, br, p-CH), −0.50 (−10.00) (36H, br,
1
3
1
Me Si), resonance for CHSi is not observed. C{ H} NMR (C D ,
3
6
6
2
98 K, in ppm): δ 162.5 (br, C ), 140.0 (br, C ), resonances for
Ph Ph
3
1
1
29
1
CH(SiMe ), i-C, and Me Si are not observed. P{ H} and Si{ H}
3
3
NMR (C D , 298 K, in ppm): NMR silent. Magnetic susceptibility
6
6
8
8
(
Evan’s method in toluene-H , toluene-d , 298 K): 5.2 μ . UV/vis (n-
hexane, λmax in nm, εM in M cm ): 371 (1546), 300 (4079), 264
6173). Mo
B
−1
−1
−1
−1
(
̈
ssbauer (80 K, 0.0 T): 0.55 mms (ΔE = 0.73 mms ).
Q
43
absorption using intensities of redundant reflections using SADABS.
Elemental analysis calculated for C H FeN PSi : C, 56.32; H, 8.48;
3
4
61
2
5
The structures were readily solved by direct and Patterson methods
N, 3.86. Found: C, 56.56; H, 8.88; N, 3.75.
and subsequent difference Fourier techniques. The Bruker
Preparation of [(Im)Fe(N(SiMe ) ) ] (2c). 1,3-iso-Propyl-2-
44
3 2 2
ShelXTL2 software package was used for solution, refinement,
and artwork of the structures. All non-hydrogen atoms were
anisotropically refined, and hydrogen atoms were placed at calculated
positions and refined as riding atoms with isotropic displacement
parameters. Crystal and data collection details are given in Tables S3
and S4 (see SI). The [((SiMe ) N) FeC] unit of 2a was found to be
methylene-benzimidazole (1c, 118.7 mg, 0.55 mmol) was added to
a stirring solution of [Fe(N(SiMe ) ) ] (206.0 mg, 0.55 mmol) in
3
2 2
toluene (2 mL)/ and the resulting yellow solution was stirred for 10
min at ambient temperature. All volatiles were removed in vacuo to
afford a colorless solid. n-Hexane (2 mL) was added to give an almost
clear solution that was filtered. (Me Si) O (2 mL) was added to the
3
2
2
3
2
severely disordered. A split atom model with restrained bond
distances and displacement parameters using the EADP, SAME, and
ISOR instructions of ShelXL was refined to account for the disorder
filtrate, and the mixture was stored at −35 °C for 7 days to give large
amounts of crystalline material. The supernatant was removed by
decantation and the residue was dried in vacuo to give 2c as highly air
sensitive colorless needles. 2c slowly decomposes at ambient
temperatures by changing its color to brown and therefore needs to
be stored at low temperatures (−35 °C).
(
293 restraints; 0.52/0.48 occupation ratio). A SiMe group in the
3
structure of 2c was also disordered and treated similarly (31
restraints; 0.67/0.33 occupation ratio). Crystals of 6 contained a
severely disordered fluorobenzene molecule, which was removed
Yield: 154 mg (52%), mp: decomp.: > 88 °C. IR (ATR, 298 K, in
45
using Platon/SQUEEZE.
Preparation of [(Ph PCH )Fe(N(SiMe ) ) ] (2a). A solution of
−1
cm ): 406 (vw), 414 (vw), 421 (vw), 500 (vs), 554 (m), 625 (w),
3
2
3 2 2
6
8
38 (m), 658 (w), 705 (vw), 731 (w), 739 (w), 781 (vw), 821 (w),
65 (vw), 892 (vw), 942 (vw), 985 (w), 1094 (vw), 1148 (vs), 1203
[
Fe(N(SiMe ) ) ] (1.51 g, 4.00 mmol) in THF (4 mL) was added to
3 2 2
a stirring solution of Ph PCH (1a, 1.11 g, 4.00 mmol) in THF (5
3
2
(
(
2
vs), 1231 (s), 1353 (vw), 1375 (vw), 1476 (vw), 1489 (vw), 1502
vw), 1602 (vw), 1625 (vw), 2894 (vw), 2945 (vw), H NMR (C D ,
mL), and the resulting light green reaction mixture was stirred for 1 h
at ambient temperature. All volatiles were removed in vacuo to afford
a pale green solid. n-Pentane (5 mL) was added to give a pale green
solution followed by the addition of (Me Si) O (4 mL) resulting in
1
6
6
98 K, in ppm): δ −0.6 (12H, br, iPr-CH ), −1.88 (36H, br,
3
−
N(Si(CH ) )), −5.24 (4H, br, CH-aryl), −9.16 (2H, br, iPr-CH),
3
2
3
2
13 1
the resonance for CH is not observed. C{ H} NMR (C D , 298 K,
2
6
6
the formation of pale green crystalline material. The volume of the
reaction mixture was reduced to 1/2 of its volume, and the
supernatant was removed by decantation. The crystalline material
was washed with (Me Si) O (3·0.5 mL) and dried in vacuo to give 2a
in ppm): NMR-silent. Magnetic susceptibility (Evan’s method in
8
8
toluene-H , toluene-d , 298 K): 5.5 μ . Mossbauer (80 K, 0.0 T): 0.51
̈
B
−
1
−1
mms (ΔE = 1.14 mms ). Elemental analysis of sufficient quality
could not be obtained due to rapid decomposition of 2c during
sample preparation and injection.
Q
3
2
as highly air sensitive, pale green crystals. 2a slowly decomposes at
ambient temperatures by changing its color to brown and therefore
needs to be stored at low temperatures (−35 °C). Yield: 2.23 g
Preparation of [(μ-Ph PCH)Fe(N(SiMe ) )] (4). Method A:
3
3 2 2
−
1
Solid 2a (210 mg, 0.32 mmol) was heated to 135 °C for 12 h. The
resulting brown melt containing crystalline material was stored for 24
h at −35 °C. The residual orange-brown crystalline material was
washed with CH Cl (1 mL) and dried in vacuo (yield: 29 mg, 18%).
(
(
85%). mp: 126 °C. IR (ATR, 298 K, in cm ): 689 (s), 716 (s), 741
s), 748 (s), 781 (s), 821 (vs), 876 (m), 966 (s), 1112 (w), 1237 (m),
1
2
437 (w), 1486 (vw), 1968 (vw), 2157 (vw), 2441 (vw), 2890 (vw),
1
943 (vw). H NMR (C D , 298 K, in ppm): δ 11.15 (6H, br, o/m-
2
2
6
6
Method B: A solution of Ph PCH (1a, 110.6 mg, 0.40 mmol) in
CH), 9.09 (6H, br, m/m-CH), 6.86 (2H, br, CH ), 4.19 (3H, br, p-
3
2
2
THF (1 mL) was added to a stirring solution of [Fe(N(SiMe ) ) ]
CH), −3.04 (36H, br, Me Si), resonance for CH is not observed.
3 2 2
3
2
13
1
(74.0 mg, 0.2 mmol) in THF (1 mL). The reaction mixture was
stirred for 10 min followed by removal of all volatiles in vacuo. The
yellow, sticky residue was heated to 135 °C for 24 h to give a brown
residue. CH Cl (1 mL) was added, and the resulting suspension was
C{ H} NMR (C D , 298 K, in ppm): δ 177.4 (6C, br, o/m-C),
6
6
1
48.2 (3C, s, p-C), 145.1 (6C, br, o/m-C4), resonances for CH , i-C,
2
3
1
1
29
1
and Me Si are not observed. P{ H} and Si{ H} NMR (C D , 298
3
6
6
K, in ppm): NMR silent. Magnetic susceptibility (Evan’s method in n-
hexane, CD Cl , 298 K): 4.9 μ . UV/vis (n-hexane, λ in nm, εM in
2
2
stored for 1 week at −35 °C. The brown suspension was filtered, and
2
2
B
max
−
1
−1
the residue was washed with CH Cl (4 × 0.2 mL) and dried in vacuo
M
cm ): 354 (1125), 266 (8158), 261 (8050), 273 (7435).
2
2
ssbauer (80 K, 0.0 T): 0.54 mms− (ΔE = 0.92 mms ).
1
−1
to give an air sensitive, orange-red powder (yield: 27 mg, 28%). mp:
Mo
Elemental analysis calculated for C H FeN PSi : C, 57.03; H, 8.18;
̈
Q
−
1
decomp. > 285 °C. IR (ATR, 298 K, in cm ): 403 (vw), 411 (vw),
39 (w), 446 (w), 468 (w), 513 (vs), 536 (s), 579 (vs), 610 (w), 625
w), 661 (m), 690 (vs), 709 (vs), 743 (s), 788 (m), 817 (vs), 841 (s),
67 (vs), 885 (s), 918 (vw), 929 (vw), 980 (vs), 1003 (w), 1029
3
1
53
2
4
4
(
8
N, 4.29. Found: C, 56.92; H, 7.15; N, 4.17; Deviation of the H value
(
Δ = 1.03) is explained by rapid decomposition of 1a during sample
preparation and injection.
(
(
vw), 1100 (m), 1111 (w), 1183 (vw), 1236 (m), 1251 (w), 1435
m), 1482 (vw), 1981 (vw), 2891 (vw), 2948 (w), 3052 (vw). H
Preparation of [(Ph PCH(SiMe ))Fe(N(SiMe ) ) ] (2b). Tol-
3
3
3 2 2
1
uene (2 mL) was added to a mixture of [Fe(N(SiMe ) ) ] (376.3 mg,
3
2 2
NMR (C D , 298 K, in ppm): δ 131.58 (2H, s, CH-PPh ), 6.66 (12H,
1
.00 mmol) and Ph PCH(SiMe ) (1b, 348.5 mg, 1.00 mmol), and the
6
6
3
3
3
br, o/m-CH), 6.13 (6H, br, p-CH), 4.84 (12H, br, o/m-CH), −0.25
resulting green-yellow solution was stirred for 1 h at ambient
temperature. All volatiles were removed in vacuo to afford a pale green
solid. n-Hexane (2 mL) was added to give a suspension, which was
stored for 12 h at −35 °C to give large amounts of crystalline, pale
green solid. The supernatant was removed by decantation, the
crystalline residue was washed with n-pentane (0.5 mL) and dried in
vacuo to give 2b as analytically pure, highly air sensitive, pale green
1
3
1
(
36H, br, SiMe ). C{ H} NMR (C D , 298 K, in ppm): δ 133.0
3 6 6
(12C, br, o/m-C), 132.9 (6C, br, p-C), 130.2 (12C, br, o/m-C).
3
1
1
29
1
P{ H}− Si{ H} NMR (C
Mossbauer (80 K, 0.0 T): 0.35 mms (ΔE = 1.75 mms ).
Elemental analysis calculated for C H Fe N P Si : C, 61.09; H,
D , 298 K, in ppm): NMR silent.
6
6
−
1
−1
̈
Q
5
0
68
2
2
2
4
6.97; N, 2.85. Found: C, 60.95; H, 6.84; N, 2.90.
G
Inorg. Chem. XXXX, XXX, XXX−XXX