3572 Organometallics, Vol. 20, No. 16, 2001
Schrodi et al.
[MesNMe]Zr Np 2 (3). A solution of NpLi (71 mg, 0.92 mmol)
in ether (2 mL) was cooled at -20 °C for 10 min and added to
a cold slurry of [MesNMe]ZrCl2 (205 mg, 0.4 mmol) in ether
(5 mL). The reaction mixture was warmed to room tempera-
ture and stirred for 15 min. The white precipitate was filtered
off on a Celite bed, and the volatile solvents were removed
from the filtrate under reduced pressure. The residual solid
was washed with pentane (2 × 2 mL) and dried under reduced
pressure to afford a yellow solid material (150 mg, 0.26 mmol)
in 65% yield: 1H NMR δ 6.93 (s, 4, Ar), 3.33 (m, 2, CH2), 3.12
(m, 2, CH2), 2.63 (m, 2, CH2), 2.60 (s, 6, Meo), 2.48 (s, 6, Meo),
2.21 (m, 2, CH2), 2.19 (s, 3, NMe), 2.18 (s, 6, Mep), 1.35 (s, 9,
ZrCH2C(CH3)3), 1.15 (s, 2, ZrCH2C(CH3)3), 0.68 (s, 9, ZrCH2C-
(CH3)3), 0.65 (s, 2, ZrCH2C(CH3)3); 13C NMR δ 149.27 (C, Ar),
134.86 (C, Ar), 134.72 (C, Ar), 134.16 (C, Ar), 130.36 (CH, Ar),
130.17 (CH, Ar), 97.45 (ZrCH2C(CH3)3), 82.63 (ZrCH2C(CH3)3),
56.87 (CH2), 55.53 (CH2), 36.75, 36.17, 36.06, 34.52, 21.31,
20.05.
Dim er of [(a ctiv-MesNMe)Zr ][B(C6F 5)4] (42). [Ph3C]-
[B(C6F5)4] (76 mg, 0.08 mmol) was added as a solid to a cold
solution (-30 °C) of 2 (42 mg, 0.08 mmol) in C6H5Br (2 mL).
The solution immediately turned dark orange, and evolution
of gas was observed. The solution was stirred for 10 min at
room temperature and was then added to vigorously stirred
cold pentane (4 mL). An orange solid precipitated and was
collected on a frit. The solid was washed with more pentane
(2 × 2 mL) and dried under reduced pressure to give an orange
powder that was not soluble in C6D5Br; yield ∼80%. Anal.
Calcd for C47H32N3BF20Zr: C, 50.37; H, 2.88; N; 3.75. Found:
C, 50.46; H, 2.85; N, 3.68.
were removed under reduced pressure, and ether (30 mL) was
added to the residue. A white solid was filtered off on Celite
and washed with ether (2 × 5 mL). The volume of the solution
was reduced to ∼15 mL in vacuo, and some solid material
precipitated. The vial was stored at -20 °C overnight, and the
crystalline material was collected on a frit, washed with
pentane (2 × 5 mL), and dried in vacuo to afford a white
powder (1.59 g), which contains approximately one molecule
of THF per Zr, according to 1H NMR spectroscopy; yield 94%.
The THF adduct can be used as is or recrystallized slowly from
ether at -20 °C over a fews days to afford a THF free
product: 1H NMR δ 6.94 (s, 4, Ar), 6.80 (s, 2, Ar), 3.39 (m, 2,
CH2), 3.10 (m, 6, CH2), 3.06 (s, 6, NMe2), 2.85 (m, 2, CH2), 2.67
(s, 3, NMe), 2.62 (m, 2, CH2), 2.50 (s, 6, MeAr), 2.44 (s, 6, MeAr),
2.37 (s, 6, NMe2), 2.29 (s, 6, MeAr), 2.19 (s, 6, MeAr), 2.15 (s, 3,
MeAr); 13C{1H} NMR δ 150.10, 145.96, 137.62, 135.61, 134.42,
134.02, 132.21, 130.49, 129.73, 129.61, 53.77 (s, CH2), 52.30
(s, CH2), 51.01 (s, CH2), 47.98 (s, CH2), 44.79 (s, NMe2), 42.72
(s, NMe2), 41.79 (s, NCH3), 21.34 (s, Me), 21.24 (s, Me), 19.91
(s, Me), 19.62 (s, Me), 19.55 (s, Me). Anal. Calcd for C38H60N6-
Zr: C, 65.94; H, 8.74; N, 12.14. Found: C, 66.12; H, 8.80; N,
12.06.
[(MesNCH2CH2)2NCH2CH2N(13CH3)Mes]Zr (NMe2)2 (6b).
The 13C-labeled analogue of 6a was prepared in a manner
similar to that for 5 using 13CH3I as the alkylating agent. NMR
data are analogous to those for 6a except the resonance for
the labeled methyl in the 1H NMR spectrum appears as a
doublet at 2.67 ppm (1J CH ) 134 Hz).
[(MesNCH2CH2)2NCH2CH2N(Me)Mes]Zr Cl2 (7a ). Two
equivalents of lutidinium chloride (220 mg, 1.53 mmol) was
added as a solid to a solution of 6a (530 mg, 0.766 mmol) in
ether (30 mL) at -20 °C. A white solid precipitated rapidly
from solution. The white precipitate was collected on a frit,
washed with pentane (2 × 5 mL), and dried to afford white
crystalline product (435 mg, 0.645 mmol) in 84% yield: 1H
NMR δ 6.88 (s, 2, Ar), 6.81 (s, 2, Ar), 6.78 (s, 2 Ar), 3.44 (m, 4,
CH2), 2.98 (m, 4, CH2), 2.78 (m, 2, CH2), 2.62 (m, 2, CH2), 2.61
(s, 3, NMe), 2.48 (s, 6, MeAr), 2.45 (s, 6, MeAr), 2.26 (s, 6, MeAr),
2.12 (s, 9, MeAr). Anal. Calcd for C34H48Cl2N4Zr: C, 60.51; H,
7.17; N, 8.30; Cl, 10.51. Found: C, 60.68; H, 7.23; N, 6.98; Cl,
10.59.
Sin gle Cr ysta ls of 42. [Ph3C][B(C6F5)4] (88.0 mg, 94.5 µmol)
was added to a cold solution (-30 °C) of [MesNMe]ZrMe2 (45.0
mg, 94.5 µmol) in C6D5Br (2.0 mL) in a 4 mL vial to yield
1
{[MesNMe]ZrMe}[B(C6F5)4] quantitatively according to the H
NMR spectrum. The orange solution was then left at room
temperature for 2 days to give dark orange needles of 42 (105.0
mg, 80.3 µmol) in 85% yield (after decanting C6D5Br, washing
with pentane, and drying in vacuo). The crystals were insoluble
in benzene, toluene, bromobenzene, N,N′-dimethylaniline, or
a mixture of bromobenzene and N,N′-dimethylaniline.
[(MesNCH 2CH 2)2NCH 2CH 2NH Mes]Zr (NMe2)2 (5). Zr-
(NMe2)4 (1.02 g, 3.8 mmol) was added as a solid to a solution
of (MesNHCH2CH2)3N (1.91 g, 3.8 mmol) in toluene (20 mL)
that had been previously cooled to -20 °C. The reaction
mixture was stirred at room temperature for 5 h. The volatile
solvents were then removed under reduced pressure. Pentane
(20 mL) was added to the residual oil, and the solution was
allowed to stand at -30 °C overnight. The pentane was
decanted and the crystalline material was collected and dried
under reduced pressure to afford a white solid (2.4 g, 3.5 mmol)
in 93% yield: 1H NMR δ 6.93 (s, 4, Ar), 6.79 (s, 2, Ar), 3.39
(m, 2, CH2), 3.12 (m, 4, CH2), 3.07 (s, 6, NMe2), 2.93 (m, 4,
CH2), 2.66 (m, 2, CH2), 2.49 (s, 6, MeAr), 2.43 (s, 6, MeAr), 2.36
(s, 6, NMe2), 2.19 (s, 6, MeAr), 2.19 (s, 6, MeAr), 2.17 (s, 3, MeAr);
13C{1H} NMR δ 150.03, 143.17, 134.43, 133.99, 132.24, 130.44,
130.34, 129.72, 129.63, 53.75 (s, CH2), 52.58 (s, CH2), 44.94
(s, NMe2), 42.68 (s, NMe2), 41.49 (s, CH2), 21.41 (s, Me), 21.23
(s, Me), 19.96 (s, Me), 19.62 (s, Me), 19.06 (s, Me). Anal. Calcd
for C37H58N6Zr: C, 65.53; H, 8.62; N, 12.39. Found: C, 65.48;
H, 8.70; N, 12.23.
[(MesNCH2CH2)2NCH2CH2N(Me)Mes]Zr (NMe2)2 (6a ). A
1.4 M solution of MeLi in ether (1.59 mL, 2.2 mmol) was added
dropwise to a solution of 5 (1.43 g, 2.1 mmol) in THF (35 mL)
that had been cooled to -20 °C. Gas evolution was observed
as MeLi was added and proceeded for a couple of minutes after
addition was complete. The reaction mixture turned yellow and
was stirred at room temperature for 5 min after gas evolution
ceased. An excess of MeI (270 µL) was then added via syringe
at room temperature. The solution turned colorless im-
mediately and slowly became cloudy. The reaction mixture was
left at room temperature for 35 min. The volatile components
[(MesNCH2CH2)2NCH2CH2N(13CH3)Mes]Zr Cl2 (7b). The
13C-labeled analogue of 7a was prepared in a manner similar
1
to that for 7a starting with 6b. H NMR data are analogous
to data for 7a except the resonance of the labeled methyl in
the 1H NMR appears as a doublet at 2.61 ppm (1J CH ) 134
Hz). The resonance of the labeled methyl appears as a singlet
at 41.49 ppm in the 13C{1H} NMR spectrum.
[(MesNCH2CH2)2NCH2CH2N(Me)Mes]Zr Me2 (8a ). A 1.0
M solution of MeMgI in ether (0.23 mL, 0.68 mmol) was added
via syringe to a vigorously stirred suspension of 7a (200 mg,
0.30 mmol) in ether (12 mL) at room temperature, and the
reaction mixture was stirred for 1.5 h. Volatile solvents were
removed under reduced pressure, and the residue was redis-
solved in toluene (∼8 mL). Excess dioxane was added to assist
the removal of Mg salts. The mixture was stirred for 10 min
to afford a milky slurry. Filtration through Celite, evaporation
of the solvents from the filtrate, and trituration of the residue
with pentane afforded 8a as white crystalline material (160
mg, 0.24 mmol) in 80% yield: 1H NMR δ 6.98 (s, 2, Ar), 6.93
(s, 2, Ar), 6.76 (s, 2, Ar), 3.67 (m, 2, CH2), 3.03 (m, 2 + 4, CH2),
2.62 (s, 3, NMe), 2.60 (m, 4, CH2), 2.45 (s, 6, MeAr), 2.42 (s, 6,
MeAr), 2.24 (s, 6, MeAr), 2.18 (s, 6, MeAr), 2.14 (s, 3, MeAr), 0.57
(s, 3, ZrMe), 0.25 (s, 3, ZrMe); 13C{1H} NMR δ 146.25, 145.30,
137.55, 136.57, 136.24, 135.84, 134.31, 130.64, 130.34, 130.10,
56.23 (CH2), 55.85 (CH2), 48.17 (CH2), 43.57 (s, ZrMe), 43.09
(CH2), 41.83 (NMe), 40.65 (s, ZrMe), 21.42 (MeAr), 21.16 (MeAr),
19.61 (MeAr), 19.19 (MeAr), 19.12 (MeAr).
[(MesNCH2CH2)2NCH2CH2N(13CH3)Mes]Zr Me2 (8b). The
preparation of 8b was analogous to that of 8a starting with
7b. NMR spectroscopy data are analogous to those in 8a except