3
66
K.C. Jantunen et al. / Journal of Alloys and Compounds 444–445 (2007) 363–368
4
. Experimental
299 K): δ 183.58 (s, quat Ar C), 136.29 (Ar C), 127.30 (Ar C), 126.02 (Ar C),
12.64 (s, C5H5).
1
4
.1. Methods and materials
4
5 5 2 2
.5. Preparation of (C H ) Hf(Ph) (16)
◦
Reactions and manipulations were performed at 21 C in a recirculating
Vacuum Atmospheres inert atmosphere (He) drybox with a MO-40-2 Dri-Train.
Glassware was dried overnight at 150 C before use. NMR spectra were obtained
The synthesis of 16 was performed in an analogous manner to 14. Reaction
of (C H ) HfCl (13) (0.757 g, 1.99 mmol) with phenyl magnesium bromide
◦
5
5 2
2
using a Bruker Avance 300 MHz spectrometer. Chemical shifts were refer-
(3.0 M soln/Et O, 1.66 mL, 4.99 mmol) and dioxane (1.02 mL, 11.97 mmol)
2
1
enced to the protio solvent impurity in benzene-d6 at δ 7.15 ppm ( H) and
gave 16 as a white powder (0.835 g, 1.80 mmol, 91%). Crystals suitable for
1
3
1
1
δ 128.39 ppm ( C{ H}) or toluene-d8 at δ 2.09 ppm ( H). Unless otherwise
noted, reagents were purchased from commercial suppliers and used without
further purification. Celite (Aldrich) and alumina (Brockman I, Aldrich) were
X-ray crystallographic analysis were obtained overnight from cooling a 1:1
toluene:pentane solution of 16 at −30 ◦C. 1H NMR (C D , 298 K): δ 7.32 (m,
6
6
8H, Ar H), 7.10 (t, 2H, para H), 5.73 (s, 10H, C H ). 13C{1H} NMR (C D ,
5
5
6
6
◦
dried under dynamic vacuum at 250 C for 48 h prior to use. Anhydrous toluene
298 K): δ 192.32 (s, quat Ar C), 138.13 (Ar C), 127.62 (Ar C), 125.77 (Ar C),
112.32 (s, C H ).
(Aldrich), pentane (Aldrich), diethyl ether (Aldrich), dioxane (Aldrich), ben-
5
5
zonitrile (Aldrich), pyridine (Aldrich), and 2-picoline (Aldrich) were passed
through a column of activated alumina under nitrogen and stored over acti-
vated 4 A˚ molecular sieves prior to use. Deuterated solvents were dried by
4
.6. Preparation of (C
5 5 2 2 2
H ) Zr(CH Ph) (15)
storage over activated 4 A˚ molecular sieves. Pyridine N-oxide (Acros) and
A 125 mL side-arm flask equipped with a stir bar was charged with
(C5H5)2ZrCl2 (12) (0.745 g, 2.55 mmol) and diethyl ether (60 mL). To the result-
ing colorless slurry was added benzyl magnesium chloride (1.0 M soln/Et2O,
.37 mL, 6.37 mmol) with stirring. The reaction mixture immediately became
clear and yellow in color. After 10 min of stirring dioxane (1.30 mL, 15.29 mmol)
was added to the reaction solution immediately forming a precipitate. After 2 h
of continued stirring the volatiles were removed under reduced pressure to give a
yellow solid. The solid was extracted with toluene (60 mL) and filtered through a
Celite-padded coarse frit. The filtrate was collected and the toluene was removed
under reduced pressure to give 15 as a yellow powder (0.880 g, 2.18 mmol, 86%).
2
-picoline N-oxide (Aldrich) were dissolved in toluene and passed through
◦
a column of activated alumina and recrystallized (from toluene at −30 C)
prior to use. (C5Me5)2Zr(CH3)2 (3) [1a] and (C5Me5)2Hf(CH3)2 (4) [1e]
were prepared according to the literature procedures. (C5H5)2Zr(CH3)2 (1)
6
[
(
21], (C5H5)2Hf(CH3)2 (2) [21], (C5H5)2Zr(Ph)2 (14) [21], (C5H5)2Hf(Ph)2
16) [21], (C5H5)2Zr(CH2Ph)2 (15) [22], (C5H5)2Hf(CH2Ph)2 (17) [23] were
prepared using modifications to the literature procedures which are detailed
below.
4
.2. Preparation of (C
5
H
5
)
2
Zr(CH
3
)
2
(1)
1
H NMR (C6D6, 299 K): δ 7.22 (m, 4H, Ar H), 6.91 (m, 6H, Ar H), 5.51 (s, 10H,
1
3
1
C5H5), 1.82 (s, 4H, CH2Ph). C{ H} NMR (C6D6, 300 K): δ 152.68 (s, quat
Ar C) 128.87 (Ar C), 126.41 (Ar C), 121.64 (Ar C), 112.59 (s, C5H5), 61.15 (s,
CH2Ph).
A 125 mL side-arm flask equipped with a stir bar was charged with
C5H5)2ZrCl2 (12) (0.761 g, 2.60 mmol) and diethyl ether (60 mL). To the result-
ing colorless slurry was added methyl magnesium bromide (3.0 M soln/Et2O,
.17 mL, 6.51 mmol) with stirring. The reaction mixture immediately became
clear and colorless. After 45 min of stirring at room temperature, dioxane
1.33 mL, 15.62 mmol) was added to the reaction mixture giving rise to an
(
2
4
5 5 2 2 2
.7. Preparation of (C H ) Hf(CH Ph) (17)
(
The synthesis of 17 was performed in an analogous manner to 15. Reaction
of (C5H5)2HfCl2 (13) (0.757 g, 1.99 mmol) with benzyl magnesium chloride
1.0 M soln/Et2O, 4.99 mL, 4.99 mmol) and dioxane (1.02 mL, 11.97 mmol)
immediate white precipitate. After 1 h of continued stirring the volatiles were
removed under reduced pressure to afford a white solid. The solid was extracted
with toluene (60 mL) and filtered through a Celite-padded coarse frit. The filtrate
was collected and the toluene was removed under reduced pressure. The resul-
tant product was triturated with pentane (20 mL) and the volatiles were removed
under reduced pressure to give 1 as a white powder (0.614 g, 2.44 mmol, 94%).
(
gave 17 as a yellow powder (0.920 g, 1.87 mmol, 94%). Crystals suitable for
X-ray crystallographic analysis were obtained overnight from cooling a 1:1
◦
1
toluene:pentane solution of 17 at −30 C. H NMR (C6D6, 298 K): δ 7.27 (m,
4
H, Ar H), 6.89 (m, 6H, Ar H), 5.47 (s, 10H, C5H5), 1.54 (s, 4H, CH2Ph).
1
13
1
H NMR (C6D6, 297 K): δ 5.70 (s, 10H, C5H5), −0.14 (s, 6H, CH3). C{ H}
NMR (C6D6, 298 K): δ 110.72 (s, C5H5), 30.62 (s, CH3).
13
1
C{ H} NMR (C6D6, 298 K): δ 152.58 (s, quat Ar C) 128.65 (Ar C), 127.01
(
Ar C), 121.97 (Ar C), 111.85 (s, C5H5), 64.97 (s, CH2Ph).
4
5 5 2 3 2
.3. Preparation of (C H ) Hf(CH ) (2)
4
.8. Crystal structure determination
The synthesis of 2 was performed in an analogous manner to 1. Reaction
of (C5H5)2HfCl2 (13) (0.752 g, 1.98 mmol) with methyl magnesium bromide
3.0 M soln/Et2O, 1.65 mL, 4.95 mmol) and dioxane (1.01 mL, 11.87 mmol)
Crystal data for 16 (C22H20Hf): M = 462.87, orthorhombic, space group
Aba2, a = 8.256(3) A˚ , b = 16.470(5) A˚ , c = 12.813(4) A˚ , V = 1742.2(10)
(
3
−3
◦
A˚ , Z = 4, Dcalc = 1.765 g cm , T = 203(2) K, θ range 2.47–27.29 , μ(Mo
1
gave 2 as a white powder (0.633 g, 1.87 mmol, 94%). H NMR (C6D6, 298 K):
−1
K␣) = 5.984 mm , 4584 reflections collected, 1333 reflections with I > 2σ(I).
R = 0.0175 (obs. data), wR2 = 0.0430 (all data), GOF = 1.186 (F ).
1
3
1
δ 5.63 (s, 10H, C5H5), −0.32 (s, 6H, CH3). C{ H} NMR (C6D6, 299 K): δ
10.22 (s, C5H5), 36.84 (s, CH3).
2
1
Crystal data for 17 (C24H24Hf): M = 490.92, orthorhombic, space group
pbca, a = 11.477(3) A˚ , b = 15.912(5) A˚ , c = 21.013(6) A˚ , V = 3837.4(19)
A˚ , Z = 8, D = 1.699 g cm , T = 203(2) K, θ range 1.94–27.49 , μ(Mo
3
−
3
◦
4
.4. Preparation of (C
5
H
5
)
2
Zr(Ph)
2
(14)
calc
−
1
K␣) = 5.439 mm , 32456 reflections collected, 3338 reflections with I > 2σ(I).
2
A 125 mL side-arm flask equipped with a stir bar was charged with
C5H5)2ZrCl2 (12) (0.749 g, 2.56 mmol) and diethyl ether (60 mL). To the result-
ing colorless slurry was added phenyl magnesium bromide (3.0 M soln/Et2O,
.14 mL, 6.41 mmol) with stirring. The reaction mixture immediately became
clear and pale yellow in color. After 10 min of stirring dioxane (1.31 mL,
5.37 mmol) was added to the reaction mixture immediately forming a white
R = 0.0427 (obs. data), wR2 = 0.0931 (all data), GOF = 1.189 (F ).
(
Single crystals of 16 (0.30 mm × 0.25 mm × 0.10 mm) and 17
(0.38 mm × 0.38 mm × 0.10 mm) were mounted from Paratone-N oil
under argon gas flow onto a glass fiber and placed on a Bruker P4/CCD
diffractometer, equipped with a Bruker LT-2 temperature device. A hemisphere
2
◦
1
of data was collected using ϕ scans, with 30 s frame exposures and 0.3 frame
precipitate. After 15 h of continued stirring the volatiles were removed under
reduced pressure to give a pale pink solid. The solid was extracted with toluene
widths. The instrument was equipped with graphite monochromatized Mo
K␣ X-ray source (λ = 0.71073 A˚ ). Data collection and initial indexing and
(
60 mL) and filtered through a Celite-padded coarse frit. The filtrate was col-
cell refinement were handled using SMART software [28]. Frame integration
and final cell parameter calculations were carried out using SAINT software
[29]. The data were corrected for absorption using the SADABS program
[30]. Decay of reflection data was monitored by analysis of redundant frames.
lected and the toluene was removed under reduced pressure to give 14 as an
orange powder (0.957 g, 2.55 mmol, 95%). H NMR (C6D6, 298 K): δ 7.25 (m,
8
1
1
3
1
H, Ar H), 7.11 (t, 2H, para H), 5.76 (s, 10H, C5H5). C{ H} NMR (C6D6,