Zr and Hf Complexes with Diamido-N-Donor Ligands
Organometallics, Vol. 23, No. 19, 2004 4371
133.41, 131.56, 129.94, 129.64, 129.34, 129.26, 127.45, 118.24,
117.08, 114.43, 114.37, 51.82, 50.48, 46.17, 29.98, 20.75, 18.51.
HRMS: calcd [M + H]+ 408.3282, found [M + H]+ 408.3264.
[1]Zr (NMe2)2 (3a ). To a cold solution (-25 °C) of 1.386 g
(2.98 mmol) of 1 in 8 mL of pentane was added dropwise a
cold solution of 0.810 g of Zr(NMe2)4 in 8 mL of pentane. A
slight darkening of the solution occurred upon addition of the
Zr(NMe2)4. The reaction was stirred for 15 min, then allowed
to stand at RT for 24 h. The reaction solution was concentrated
until a precipitate formed. The precipitate was collected by
filtration and washed with pentane, yielding 1.440 g (76%) of
3a as an off-white crystalline solid. 1H NMR (500 MHz,
C6D6): δ 7.07 (app d, 3H), 7.00 (app t, 3H), 6.94 (s, 1H), 6.90
(s, 1H), 6.85 (app t, 2H), 6.54 (d, 1H), 6.44 (t, 1H), 6.20 (d,
1H), 4.30 (t, 1H), 3.70 (td, 1H), 3.62 (app d, 1H), 3.02 (dd, 1H),
2.48 (s, 9H), 2.38 (s, 3H), 2.37 (s, 3H), 2.34 (s, 3H), 2.24 (s,
9H), 2.17 (s, 3H). Anal. Calcd for C36H47N5Zr: C, 67.45; H, 7.39;
N, 10.93. Found: C, 67.32; H, 7.28; N, 11.06.
Hf: C, 54.05; H, 4.96; Cl, 9.97; N, 5.91. Found: C, 54.11; H,
5.06; Cl, 9.93; N, 5.88.
[1]HfMe2 (4c). Compound 4c was prepared in a fashion
analogous to the synthesis of 3c from 4b (0.8135 g, 1.144
mmol) and 2 equiv of MeMgBr. The crude product was formed
in 90% yield and could be recrystallized from toluene/ether.
1H NMR (500 MHz, C6D6): δ 7.23 (d, 2H), 7.02 (m. 4H), 6.91
(s, 1H), 6.87 (app t, 2H), 6.81 (s, 1H), 6.61 (d, 1H), 6.45 (t, 1H),
6.15 (d, 1H), 3.96 (td, 1H), 3.45 (m, 2H), 3.35 (m, 1H), 2.59 (s,
3H), 2.42 (s, 3H), 2.39 (s, 3H), 2.24 (s, 3H), 2.12 (s, 3H), 1.91
(s, 3H), 0.22 (s, 3H), 0.11 (s, 3H). 13C{1H} NMR (125 MHz,
C6D6): δ 154.16, 145.80, 144.43, 143.43, 141.76, 136.75, 136.51,
136.21, 135.86, 135.47, 134.80, 131.03, 130.74, 130.57, 130.11,
129.93, 129.90, 126.69, 125.45, 121.41, 117.96, 114.53, 58.83,
58.19, 56.61, 55.36, 21.48, 21.32, 19.50, 19.47, 18.69, 17.89.
Anal. Calcd for C34H41N3Hf: C, 60.93; H, 6.17; N, 6.27.
Found: C, 61.08; H, 6.12; N, 6.23.
[2]Zr (NMe2)2 (5a ). To a cold (-25 °C) solution of 2.50 g
(6.13 mmol) of H22 in 50 mL of pentane was added dropwise
a cold solution of 1.653 g (6.179 mmol) of Zr(NMe2)4 in 20 mL
of pentane. The amber solution was allowed to warm to room
temperature and stir for 15 h. The solution was then concen-
trated to ∼10 mL and set aside at -25 °C for several hours,
during which time white crystals formed. The mother liquor
was concentrated further and chilled to -25 °C, yielding a
second crop of crystals. The crystals were collected by filtration,
washed with cold pentane, and dried in vacuo, giving 2.245 g
(63%) of 5a . The crude residue also could be dissolved in
toluene and used directly in the proceeding step without
[1]Zr Cl2 (3b). TMSCl (0.22 mL, 1.73 mmol) was added
dropwise to a cold (-25 °C) solution of 0.552 g (0.861 mmol)
of 3a in 10 mL of toluene. The reaction was allowed to stir at
RT for 24 h. All volatiles were removed in vacuo, leaving 0.400
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g (75%) of 3b as a white powder. H NMR (500 MHz, C6D6):
δ 7.28 (d, 2H), 7.05 (app t, 3H), 6.92 (t, 1H), 6.89 (s, 1H), 6.85
(s, 1H), 6.81 (t, 1H), 6.66 (s, 1H), 6.48 (t/d, 2H), 6.05 (d, 1H),
3.90 (td, 1H), 3.62 (td, 1H), 3.47 (dd, 1H), 3.37 (dd, 1H), 2.57
(s, 3H), 2.48 (s, 3H), 2.45 (s, 3H), 2.19 (s, 3H), 2.04 (s, 3H),
2.02 (s, 3H). Anal. Calcd for C32H35Cl2N3Zr: C, 61.62; H, 5.66;
Cl, 11.37; N, 6.74. Found: C, 61.54; H, 5.73; Cl, 11.43; N, 6.79.
[1]Zr Me2 (3c). A solution of 0.29 mL (0.87 mmol) of
MeMgBr (3.0 M in Et2O) was added dropwise to a cold (-25
°C) suspension of 0.256 g (0.410 mmol) of 3b in 10 mL of
diethyl ether. The reaction was allowed to warm to RT and
stir for 1 h, during which time the contents of the reaction
went into solution and a small amount of precipitate formed.
1,4-Dioxane (0.1 mL, 1.17 mmol) was added to the reaction to
precipitate the magnesium salts. The reaction was filtered
through Celite, and the volatiles were removed in vacuo to give
0.225 g (90%) of 3c as a white powder. Crystals suitable for
X-ray diffraction were grown from a concentrated ether/
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isolation of crystalline 5a . H NMR (500 MHz, C6D6): δ 7.15
(t, 1H), 7.10 (d, 1H), 7.04 (m, 4H), 6.97 (s, 1H), 6.83 (m, 1H),
6.79 (s, 1H), 6.73 (d, 1H), 6.58 (t, 1H), 4.03 (td, 1H), 3.39 (td,
1H), 3.20 (dd, 1H), 2.74 (dd, 1H), 2.71 (s, 6H), 2.61 (br s, 6H),
2.50 (s, 3H), 2.18 (s, 3H), 1.74 (s, 3H), 1.48 (s, 3H).
[2]Zr Cl2 (5b). To a cold (-25 °C) solution of 2.245 g (3.84
mmol) of 5a in toluene was added 0.97 mL (7.6 mmol) of
TMSCl. The reaction was allowed to stir at room temperature
for 3 days. All volatiles were removed in vacuo, and the residue
was treated with pentane, giving 1.927 g (88%) of 5b as a pale
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yellow crystalline powder. H NMR (500 MHz, C6D6): δ 7.04
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pentane solution. H NMR (500 MHz, C6D6): δ 7.25 (d, 2H),
(m, 5H), 6.92 (d, 1H), 6.88 (s, 1H), 6.87 (t, 1H), 6.73 (s, 1H),
6.66 (t, 1H), 6.60 (d, 1H), 4.35 (td, 1H), 3.30 (td, 1H), 3.06 (dd,
1H), 2.67 (dd, 1H), 2.62 (s, 3H), 2.11 (s, 3H), 1.78 (s, 3H), 1.41
(s, 3H). Anal. Calcd for C27H27D6Cl2N3Zr: C, 57.12; H, 6.92;
Cl, 12.49; N, 7.40. Found: C, 57.22; H, 7.08; Cl, 12.37; N, 7.34.
[2]Zr Me2 (5c). Compound 5b (1.010 g, 1.779 mmol) was
suspended in 45 mL of diethyl ether and cooled to -25 °C. A
1.10 mL (3.60 mmol) quantity of chilled MeMgBr was added
and the mixture allowed to stir at room temperature for 20
min. The ether was removed in vacuo, and the residue was
extracted into 70 mL of pentane and filtered through Celite.
The pentane was removed in vacuo, leaving 0.778 g (83% yield)
of 5c as an off-white crystalline powder. Crystals suitable for
X-ray diffraction were grown from a concentrated pentane
7.05 (s, 1H), 7.04 (s, 1H), 7.01 (t, 2H), 6.91 (s, 1H), 6.87 (m,
2H), 6.80 (s, 1H), 6.67 (d, 1H), 6.46 (t, 1H), 6.15 (d, 1H), 3.78
(td, 1H), 3.53 (dd, 1H), 3.36 (m, 2H), 2.61 (s, 3H), 2.42 (s, 3H),
2.37 (s, 3H), 2.25 (s, 3H), 2.11 (s, 3H), 1.77 (s, 3H), 0.41 (s,
3H), 0.40 (s, 3H). 13C{1H} NMR (125 MHz, C6D6): δ 153.48,
145.74, 143.86, 143.31, 141.79, 136.81, 136.48, 136.08, 135.76,
135.54, 135.11, 131.06, 130.74, 130.55, 130.26, 130.10, 129.82,
126.98, 125.23, 120.98, 117.71, 113.72, 57.54, 54.72, 49.23,
43.94, 21.49, 21.33, 19.75, 19.53, 18.65, 17.84. Anal. Calcd for
C
34H41N3Zr: C, 70.05; H, 7.09; N, 7.21. Found: C, 69.87; H,
6.96; N, 7.12.
[1]Hf(NMe2)2 (4a ). Compound 4a was prepared in fashion
that was strictly analogous to the synthesis of 3a starting from
2.67 g (5.75 mmol) of H21 and 2.044 g (5.76 mmol) of
Hf(NMe2)4. Compound 4a was isolated as 3.714 g (89%) of
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solution at -25 °C. H NMR (500 MHz, C6D6): δ 7.13 (t, 1H),
7.02 (m, 4H), 6.89 (d, 2H), 6.82 (m, 2H), 6.77 (s, 1H), 6.66 (t,
1H), 3.83 (td, 1H), 3.53 (td, 1H), 3.19 (dd, 1H), 2.88 (dd, 1H),
2.73 (s, 3H), 2.15 (s, 3H), 1.81 (s, 3H), 1.42 (s, 3H), 0.58 (s,
3H), 0.29 (s, 3H). 13C{1H} NMR (125 MHz, C6D6): δ 149.60,
148.42, 148.07, 135.16, 134.96, 134.29, 132.11, 130.35, 130.02,
129.19, 125.22, 123.27, 121.86, 120.02, 118.44, 55.67, 55.52,
54.48, 45.57, 42.90, 31.01, 21.36, 19.60, 18.13. Anal. Calcd for
C29H33D6N3Zr: C, 66.11; H, 8.61; N, 7.97. Found: C, 66.15;
H, 8.48; N, 8.06.
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white cubes. H NMR (500 MHz, C6D6): δ 7.03 (m, 5H), 6.95
(s, 1H), 6.92 (s, 1H), 6.85 (m, 3H), 6.51 (d, 1H), 6.42 (t, 1H),
6.20 (d, 1H), 4.29 (td, 1H), 3.64 (m, 2H), 3.12 (dd, 1H), 2.50 (s,
9H), 2.42 (s, 3H), 2.38 (s, 3H), 2.36 (s, 3H), 2.29 (s, 6H), 2.25
(s, 3H), 2.19 (s, 3H). Anal. Calcd for C36H47N5Hf: C, 59.37; H,
6.50; N, 9.62. Found: C, 59.46; H, 6.38; N, 9.55.
[1]HfCl2 (4b). Compound 4b was prepared in fashion
similar to the synthesis of 3b by treating 4a (3.710 g, 5.095
mmol) with 2 equiv of TMSCl. The reaction required additional
heating at 45 °C for 3.5 days to go to completion (84% isolated
[2]Hf(NMe2)2 (6a ). To a cold (-25 °C) solution of 1.51 g
(3.70 mmol) of 2 in 15 mL of toluene was added 1.317 g (3.712
mmol) of Hf(NMe2)4 in 15 mL of toluene. The resulting amber
solution was heated at 70 °C for 20 h. The toluene was removed
in vacuo, the resulting residue was dissolved in ∼5 mL of
pentane, and the solution was set aside at -25 °C for several
hours. During this time, white crystalline blocks formed in the
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yield). H NMR (500 MHz, C6D6): δ 7.25 (d, 2H), 7.03 (app t,
3H), 6.91 (app t, 2H), 6.87 (s, 1H), 6.81 (t, 1H), 6.68 (s, 1H),
6.45 (t, 1H), 6.40 (d, 1H), 6.07 (d, 1H), 4.08 (m, 1H), 3.57 (m,
1H), 3.42 (dd, 1H), 2.56 (s, 3H), 2.50 (s, 3H), 2.48 (s, 3H), 2.20
(s, 3H), 2.13 (s, 3H), 2.06 (s, 3H). Anal. Calcd for C32H35Cl2N3-