4094 Organometallics, Vol. 17, No. 18, 1998
Brussee et al.
warming to room temperature, the color changed to orange-
brown. The reaction mixture was stirred for 1 h at room
temperature before removing the solvent under reduced pres-
sure. The resulting orange solid was stripped twice with
pentane (10 mL) and subsequently extracted with 30 mL of
pentane. Concentration and cooling to -80 °C yielded 0.45 g
(0.76 mmol, 61%) of 6 as orange crystals. 1H NMR (C6D6, 200
pentane (30 mL). Concentration and cooling to -20 °C gave
0.17 g of 10 as red crystals. Concentration of the mother liquor
yielded an additional 0.1 g (0.27 g, 0.59 mmol, 72% in total).
1H NMR (C6D6, 200 MHz, 25 °C): δ 4.31 (∆ν1/2 ) 110 Hz 24H,
CH(CH3)2), 2.48 (∆ν1/2 ) 450 Hz, 18H, C(CH3)3). IR (Nujol
mull, KBr, cm-1): 3077(w), 1508(m), 1402(s), 1331(s), 1308(s),
1262(m), 1223(w), 1179(s), 1128(m), 1088(w), 1017(m), 974(w),
928(w), 891(w), 874(w), 801(m), 772(w), 746(m), 721(m), 665(w),
627(w), 550(w), 480(m), 442(w), 424(w). Anal. Calcd for
MHz, 25 °C): δ 10.62 (∆ν1/2 ) 145 Hz, 4H, Ph), 9.44 (∆ν1/2
)
31 Hz, 4H, Ph), 7.20 (∆ν1/2 ) 19 Hz, 2H, Ph), 1.86 (∆ν1/2 ) 205
Hz, 36H, SiMe3). IR (Nujol mull, KBr, cm-1): 1630(w),
1600(w), 1578(w), 1505(m), 1258(m), 1244(s), 1177(w), 1169(w),
1157(w), 1102(w), 1074(w), 1032(w), 1000(m), 978(s), 916(m),
843(s), 785(m), 758(s), 721(m), 700(m), 683(m), 635(w), 613(w),
604(w), 575(w), 532(m), 442(w). Anal. Calcd for C27H49N4-
Si4V: C, 54.69; H, 8.33; N, 9.45. Found: C, 54.55; H, 8.33; N,
9.23.
C
25H51N4V: C, 65.47; H, 11.21; N, 12.22. Found: C, 65.07; H,
11.23; N, 12.08.
Syn th esis of [t-Bu C(Ni-P r )2]V(η3-C3H5)2 (11). To a cold
solution of [t-BuC(Ni-Pr)2]VCl2(THF)2 (5) (1.26 g, 3,34 mmol)
in 20 mL of THF was added 7.5 mL of a 0.89 M allylMgCl
solution in THF. The reaction mixture was slowly warmed to
-20 °C, and the red-orange solution was stirred for half an
hour. After removing the volatiles in vacuo the residue was
stripped with pentane (15 mL) and subsequently extracted
with 30 mL of pentane. Concentration of the solution and
cooling to -80 °C yielded 11 as red bar-shaped crystals (0.45
g, 1.42 mmol, 43%). 1H NMR (C6D6, 200 MHz, 25 °C): δ 5.93
(∆ν1/2 ) 57 Hz, 12H, CH(CH3)2), 2.00 (∆ν1/2 ) 250 Hz, 9H,
C(CH3)3). IR (Nujol mull, KBr, cm-1): 3077(w), 3063(w),
1630(w), 1514(s), 1489(m), 1398(m), 1360(m), 1325(s), 1310(s),
1262(w), 1246(w), 1181(s), 1130(m), 1117(m), 1082(w), 1018(m),
920(w), 874(w), 828(s), 812(s), 775(m), 756(w), 723(m), 675(w),
662(w), 615(m), 552(w), 500(w), 465(m), 424(w). Anal. Calcd
for C17H33N2V: C, 64.53; H, 10.51; N, 8.85. Found: C, 64.00;
H, 10.60; N, 8.56.
Syn th esis of [P h C(NSiMe3)2]2VEt (7). A suspension of
1.30 g (2.12 mmol) of [PhC(NSiMe3)2]2VCl in 25 mL of ether
was cooled to -80 °C. Subsequently, EtMgBr (1.60 mL of a
1.34 M solution in ether, 2.14 mmol) was added. Upon
warming to room temperature, the orange reaction mixture
was stirred for 30 min, after which the solvent was evaporated.
The remaining solid was extracted with 25 mL of pentane.
Concentration and cooling of the solution at -80 °C yielded 7
as an orange microcrystalline powder (0.85 g, 1.40 mmol, 66%).
1H NMR (C6D6, 300 MHz, 25 °C): δ 10.50 (∆ν1/2 ) 170 Hz,
4H, Ph), 9.38 (∆ν1/2 ) 34 Hz, 4H, Ph), 7.50 (∆ν1/2 ) 17 Hz, 2H,
Ph), 0.79 (∆ν1/2 ) 340 Hz, 36H, SiMe3). IR (Nujol mull, KBr,
cm-1): 1499(m), 1258(m), 1246(s), 1167(w), 1121(w), 1072(w),
1030(w), 1001(m), 980(s), 922(w), 845(s), 785(m), 762(s),
745(m), 725(m), 702(m), 683(m), 615(w), 604(w), 527(m),
442(w).
Syn th esis of [P h C(NSiMe3)2]2V(η3-C3H5) (8). To a solu-
tion of [PhC(NSiMe3)2]2VCl (0.73 g, 1.19 mmol) in THF (25
mL) was added C3H5MgCl (1.7 mL of a 0.72 M solution in THF,
1.22 mmol) at -78 °C. The red solution was stirred for 1 h at
room temperature, after which the solvent was removed in
vacuo and the solid residue was stripped two times with 10
mL of pentane and subsequently extracted with 30 mL of
pentane. The filtrate was concentrated and cooled overnight
at -80 °C, yielding 0.50 g (0.81 mmol, 68%) of 8 as red-colored
block-shaped crystals. 1H NMR (C6D6, 200 MHz, 25 °C): δ
10.26 (∆ν1/2 ) 230 Hz, 4H, Ph), 9.17 (∆ν1/2 ) 34 Hz, 4H, Ph),
8.28 (∆ν1/2 ) 19 Hz, 2H, Ph), 1.14 (∆ν1/2 ) 191 Hz, 36H, SiMe3).
IR (Nujol mull, KBr, cm-1): 1664(w), 1630(w), 1518(w),
1499(m), 1310(w), 1260(m), 1242(s), 1169(w), 1163(w), 1099(w),
1072(w), 1028(w), 1003(m), 978(s), 918(w), 841(s), 783(m),
764(s), 725(m), 700(m), 690(m), 635(w), 613(w), 606(w), 515(m),
465(w), 442(w). Anal. Calcd for C29H51N4Si4V: C, 56.27; H,
8.30; N, 9.05. Found: C, 56.25; H, 8.32; N, 8.93.
Syn th esis of [t-Bu C(Ni-P r )2]2VMe (9). To a THF (15 mL)
solution of [t-BuC(Ni-Pr)2]2VCl (3) (0.40 g, 0.88 mmol) was
added MeMgCl (0.3 mL of a 3.0 M THF solution, 0.90 mmol)
at -80 °C. Upon warming up to room temperature, the color
of the solution changed to brown-yellow. The mixture was
stirred for 0.5 h. After evaporation of the volatiles the brown-
orange residue was stripped with pentane (2 × 10 mL) and
subsequently extracted with 25 mL of pentane. Concentration
and cooling of the solution at -80 °C afforded 9 as plate-shaped
orange crystals (0.13 g, 0.30 mmol, 34%). 1H NMR (C6D6, 200
MHz, 25 °C): δ 4.65 (∆ν1/2 ) 144 Hz, 24H, CH(CH3)2), 3.56
(∆ν1/2 ) 475 Hz, 18H, C(CH3)3). IR (Nujol mull, KBr, cm-1):
1491(s), 1402(s), 1358(s), 1327(s), 1306(s), 1225(w), 1181(s),
1159(m), 1128(m), 1119(m), 1017(m), 945(w), 926(w), 891(w),
874(w), 837(w), 814(w), 758(w), 719(m), 681(m), 669(m), 573(w),
552(w), 507(m), 425(w). Anal. Calcd for C23H49N4V: C, 63.86;
H, 11.42; N, 12.72. Found: C, 63.34; H, 11.35; N, 12.72.
Syn th esis of [t-Bu C(Ni-P r )2]2V(η3-C3H5) (10). AllylMgCl
(0.9 mL of a 0.89 M THF solution) was added to a solution of
[t-BuC(Ni-Pr)2]2VCl (3) (0.37 g, 0.82 mmol) in THF (20 mL)
After removal of the solvent the red residue was extracted with
Eth en e Oligom er iza tion by [P h C(NSiMe3)2]2VMe (6).
An NMR tube equipped with a Teflon stopcock (which can be
attached to a vacuum line) was charged with a solution of 6
mg (0.010 mmol) of [PhC(NSiMe3)2]2VMe in 0.4 mL of benzene-
d6. On a vacuum line, a portion of ethene (0.24 mmol, 24
equiv) was condensed into the NMR tube, after which the
stopcock was closed and the tube warmed to 80 °C (CAU-
TION: the initial pressure in the tube is calculated to be about
3 bar). This procedure was repeated four more times with
intervals of 24 h (monitoring the reaction by NMR spectroscopy
showed full consumption of one portion of the ethene in that
period). After full conversion of the last portion of ethene the
reaction mixture was quenched with a drop of methanol and
filtered over silica. The filtrate was analyzed by GC/MS and
quantified using an internal cyclooctane standard (4.1 mg,
0.036 mmol).
Cr ysta l Str u ctu r e Deter m in a tion s. Suitable crystals of
5, 8, and 11 were mounted on a glass needle in a drybox and
transferred under inert atmosphere into the cold nitrogen
stream on an Enraf-Nonius CAD4-F diffractometer (mono-
chromated Mo KR radiation, ∆ω ) 0.90 + 0.34 tan θ).
Accurate cell parameters and an orientation matrix were
determined from the setting angles (SET410) of 22 reflections
in the ranges 11.90° < θ < 18.42° (5), 17.69° < θ < 20.78° (8),
and 12.22° < θ < 18.21° (11). Reduced cell calculations did
not indicate any higher lattice symmetry.11 Crystal data and
details on data collection and refinement are presented in
Table 4. Intensity data were corrected for Lorentz and
polarization effects, but not for absorption. The structures
were solved by Patterson methods and subsequent difference
Fourier techniques (DIRDIF12). All calculations were per-
formed on a HP9000/735 computer with the program packages
SHELXL13 (least-squares refinements) and PLATON14 (cal-
(10) Boer, J . L. de; Duisenberg, A. J . M. Acta Crystallogr. 1984, A40,
C410.
(11) Spek, A. L. J . Appl. Crystallogr. 1988, 21, 578.
(12) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garc´ıa-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF-97 program system; Crystallography Laboratory; University
of Nijmegen: Nijmegen, The Netherlands 1997.
(13) Sheldrick, G. M. SHELX-97. Program for the Solution and
Refinement of Crystal Structures; University of Go¨ttingen: Go¨ttingen,
Germany, 1997.