Cationic Methallylnickel and -palladium Complexes
Organometallics, Vol. 24, No. 3, 2005 351
methylallylpalladium(II)] (317 mg, 0.72 mmol) in benzene (5
mL) was added to a solution of 1a (400 mg, 1.44 mmol) in
benzene (10 mL) and heated for 3 h to 40 °C, and 8a was
precipitated by addition of n-hexane (15 mL). Separation and
drying in a vacuum gave 264.4 mg (73%) of a yellow powder
of 8a, mp >220 °C. 1H NMR (C6D6): δ 1.50 (s, 3 H, CH3), 1.92
NMR (CDCl3): δ 33.2. Anal. Calcd for C22H21OPPd (438.80):
C, 60.22; H, 4.82. Found: C, 60.81; H, 5.27.
(2-Dicyclohexylphosphinophenolate)(2-methylallyl)-
palladium(II), 9b. 8b (200 mg, 0.39 mmol) was heated to 120
°C at 2.5 × 10-4 Torr for 6 h. The residue was extracted with
toluene (10 mL), and the solvent was removed (8 h, 10-4 Torr)
to give 108 mg (61%) of pale yellow 9b, mp >220 °C. DTA/TG:
endothermic peaks at 149.2, 181.9 (m), 242.2 (vs) °C, exother-
mic peak ca. 215 °C, mass loss starting > 185 °C, at 250 °C
(s, 3 H, CH3CO), 2.50 (s vbr, 2 H, 1′-H, 2′-H), 3.39 (d, JPH
)
8.9 Hz, 1 H, 3′-H), 4.65 (d, JPH ) 5.9 Hz, 1 H, 4′-H), 6.50 (tm,
3J ) 7.4, 7 Hz, 1 H, 4-H), 6.95-7.05 (m, 6 H, Ph), 7.10-7.25
(m, 2 H, 3-H, 5-H), 7.40-7.50 (m, 4 H, Ph), 7.63 (dd, J ≈ 7, 5
Hz, 1 H, 6-H), 13.09 (s br, O-H‚‚‚O). 13C NMR (C6D6): δ 22.0,
174.0 (acetic acid); 24.0 (CH3), 48.9 (C-a), 77.0 (d, J ) 31.1
1
ca. 7.8%, further decay >255 °C. H NMR (CDCl3): δ 1.05-
1.40 (m, 12 H, Cy), 1.60-2.15 (m, 10 H, Cy), 1.94 (s, 3 H, CH3),
2.31 (s br, 1 H, 1′-H), 3.27 (s br, 1 H, 2′-H), 3.49 (d, JPH ) 8.5
Hz, 1 H, 3′-H), 4.51 (dd, JPH ) 5.4, J ) 1.6 Hz, 1 H, 4′-H), 6.52
1
3
Hz, C-c), 116.6 (d, J ) 51.0 Hz, C-2), 117.2 (d, J ) 6.6 Hz,
C-4), 121.5 (d, 3J ) 8.2 Hz, C-6), 129.6 (d, 3J ) 10.6 Hz, C-m),
3
4
4
3
(tt, J ≈ 7.3, JPH ) 1.4, J ) 0.9 Hz, 1 H, 4-H), 6.91 (ddd, J
4
4
4
131.0 (d, J ) 1.9 Hz, C-p), 133.4 (d, J ) 4.7 Hz, C-b), 133.9
) 8.5, JPH ) 4.9, J ) 0.9 Hz, 1 H, 6-H), 7.10-7.21 (m, 2 H,
3-H, 5-H). 13C NMR (CDCl3): δ 23.9 (CH3), 26.1 (C-δ), 26.7 (d,
3J ) 10.9 Hz, C-γ), 26.8 (d, 3J ) 14.0 Hz, C-γ′), 28.6 (C-â),
(d, 2J ) 13.1 Hz, C-o), 134.1 (C-3), 134.4 (d, 1J ) 46.0 Hz, C-i),
134.9 (C-5), 177.2 (d, 2J ) 21.2 Hz, C-1). 31P{1H} NMR: δ
(C6D6) 31.7.
2
1
29.8 (d br, J ) 9.2 Hz, C-â′), 34.4 (d br, J ) 29.4 Hz, C-R),
1
34.7 (d br, J ) 26.8 Hz, C-R′), 42.8 (C-a), 75.8 (d, J ) 30.3
(2-Dicyclohexylphosphinophenolate)(2-methylallyl)-
palladium(II) Acetic Acid, 8b. A solution of di-µ-acetatobis-
[2-methylallylpalladium(II)] (403 mg, 0.91 mmol) in benzene
(5 mL) was added to a solution of 1b (530 mg, 1.83 mmol) in
benzene (10 mL), heated for 3 h, and allowed to cool to room
temperature. Petroleum ether (15 mL) was added, and after
2 h the precipitate was separated, washed with recondensed
solvent, and dried in a vacuum (8 h, 10-4 Torr) to give 332 mg
(71%) of a yellow powder of 8b, mp > 220 °C. IR (Nujol): νj ca.
1
3
Hz, C-c), 113.8 (d, J ) 43.4 Hz, C-2), 114.5 (d, J ) 5.9 Hz,
3
C-4), 119.6 (d, J ) 7.8 Hz, C-6), 130.8 (d, J ) 4.7 Hz, C-b),
131.7, 132.9 (2s, C-3, C-5), 177.8 (d, 2J ) 17.8 Hz, C-1).
31P{1H} NMR (CDCl3): δ 53.3. Anal. Calcd for C22H33OPPd
(450.90): C, 58.60; H, 7.38. Found: C, 59.15; H, 8.03.
Crystal Data and Structure Determination of 4a‚THF.
A suitable colorless crystal of 4a‚THF was mounted under
argon inside a thin-wall glass capillary, transferred onto a
Bruker/Nonius Apex-X8 diffractometer, and cooled in a stream
of cold dinitrogen to -60 °C. Diffraction data were measured
using graphite-monochromated Mo KR radiation (λ ) 0.71073
Å). Data collection, cell refinement, and data reduction were
made using APEX2, Smart, Saint, and SADABS software.29
The cell was established to be primitive orthorhombic with a
) 8.7047(2), b ) 11.4662(2), and c ) 27.3342(7) Å; space group
P212121: The structure was solved by direct methods (SHELXS-
9730) and refined by full-matrix least-squares methods on F2
for all unique reflections (SHELXL-97).30 The positions of the
H atoms were calculated assuming idealized geometries and
refined using riding models with U(H) ) 1.2‚U(C). During the
refinement process, racemic twinning became evident with a
ratio of 0.88/0.22 for the two components. Anisotropic refine-
ment of all the atoms but H yielded R1(F) ) 0.0315 (7914 data
with Io > 2σ(Io)) and wR2(F2) ) 0.0778 (all data).
1
2500 (br w), 1749 (w), 1707 (s) cm-1 (m). H NMR (CDCl3): δ
1.02-1.41 (m, 10 H, Cy), 1.62-1.87 (m, 8 H, Cy), 1.90-2.20
(m, 4 H, Cy), 1.95 (s, 3 H, CH3), 2.07 (s, 3 H, CH3CO), 2.33 (s
vbr, 1 H, 1′-H), 3.30 (s vbr, 1 H, 2′-H), 3.51 (d, JPH ) 8.5 Hz,
1 H, 3′-H), 4.55 (d, JPH ) 5.5 Hz, 1 H; 4′-H), 6.57 (tm, 3J ) 7.5,
4
7.1, JPH ) 1.4, 4J ) 0.9 Hz, 1 H, 4-H), 6.97 (ddd, 3J ) 8.4,
4
4JPH ) 4.9, J ) 0.9 Hz, 1 H, 6-H), 7.12-7.23 (m, 2 H, 3-H,
5-H), 12.35 (br, 1 H, OH). 13C NMR (CDCl3, CH-COSY): δ 21.2,
3
174.8 (acetic acid); 23.9 (CH3), 26.1 (C-δ), 26.7 (d, J ) 11.2
Hz, C-γ), 26.8 (d, 3J ) 14.0 Hz, C-γ′), 28.6 (C-â), 29.8 (d, 2J )
1
5.2 Hz, C-â′), 34.5 (d br, J ) 23 Hz, C-R), 43.0 (C-a), 76.4 (d,
1
3
J ) 31.3 Hz, C-c), 114.0 (d, J ) 43.3 Hz, C-2), 115.3 (d, J )
5.9 Hz, C-4), 119.4 (d, 3J ) 7.2 Hz, C-6), 130.8 (d, J ) 4.4 Hz,
4
2
C-b), 131.7 (C-3), 132.9 (d, J ) 1.5 Hz, C-5), 176.4 (d, J )
17.7 Hz, C-1). 31P{1H} NMR (CDCl3): δ 52.5. Anal. Calcd for
C24H37O3PPd (510.95): C, 56.42; H, 7.30. Found: C, 57.13; H,
7.46.
Crystallographic data are given in Table 4, and selected
bond lengths and angles in Table 1.
(2-Diphenylphosphinophenolate)(2-methylallyl)palla-
dium(II), 9a. 8a (260 mg, 0.52 mmol) was heated for 6 h to
130 °C at 2 × 10-4 Torr, and the residue was extracted with
toluene. Removal of the solvent (8 h, 10-4 Torr) furnished 153
mg (67%) of pale yellow 9a, mp >220 °C. DTA/TG: exothermic
peak at 206.5 °C, decomposition begins at 130 °C, strongly at
175-206.5 °C, mass loss 12.5% (C4H7), further decay > 270
°C. 1H NMR (C6D6): δ 1.39 (s, 3 H, CH3), 2.03 (s br, 1 H,
1′-H), 2.93 (s br, 1 H, 2′-H), 3.22 (d, JPH ) 8.9 Hz, 1 H, 3′-H),
4.27 (d, JPH ) 5.8 Hz, 1 H, 4′-H), 6.54 (tm, 1 H, 4-H), 6.90-
7.08 (br, 6 H, Ph), 7.18 (td, 1 H, 3-H), 7.24 (ddt, 1 H, 5-H),
7.42 (dd br, 1 H, 6-H), 7.45-7.60 (br, 4 H, Ph). 1H NMR
(CDCl3): δ 1.98 (s, 3 H, CH3), 2.48 (s br, 1 H, 1′-H), 3.39 (s br,
1 H, 2′-H), 3.57 (d, JPH ) 9.0 Hz, 1 H, 3′-H), 4.59 (d, JPH ) 5.6
Oligomerization of Ethylene. The single-component (pre)-
catalyst (quantities of 2a, 2b, or 5a, see Table 2) was added
to toluene (20 mL), and the suspension was transferred to a
steel autoclave (75 mL), equipped with a Teflon-coated mag-
netic stirrer, gas (argon or C2H4) and sample inlet valves, a
safety diaphragm, and a manometer or HEJU pressure sensor
(1-100 bar, Juchheim) for pressure registration. Then ethyl-
ene was added. In the case of 2a and 2b the strongly
exothermic reaction of ethylene started during pressurizing
the autoclave. Addition of ethylene was stopped after about
2.5 min, and the mixture was allowed to stir for 1 h without
heating. The maximum pressure observed after 2 min was ca.
15 bar; the final pressure was ca. 3 bar. In the case of 5a
ethylene was added until a pressure of 50 bar, then the
autoclave was closed, placed into a preheated bath, and heated
overnight to 70 or 100 °C (see Table 2). The autoclave was
cooled to 0 °C, unconverted ethylene was allowed to escape,
and gaseous products were condensed in a cooling trap (-78
°C). After cooling to -50 °C the contents of the autoclave were
transferred to a flask. The oligomers were flash distilled (80-
3
4
4
Hz, 1 H, 4′-H), 6.54 (tt, J ) 7.6, 6.8, JPH ) 1.6, J ) 0.9 Hz,
3
4
4
1 H, 4-H), 6.98 (ddd, J ) 8.5, JPH ) 6.2, J ) 0.9 Hz, 1 H,
3
3
4
6-H), 7.10 (ddd, JPH ) 9.5, J ) 7.6, J ) 1.6 Hz, 1 H, 3-H),
7.21 (ddt, 3J ) 8.5, 6.8, 4J ) 1.6, JPH ) 1.4 Hz, 1 H, 5-H),
5
7.32-7.43 (vbr, 6 H, Ph), 7.47-7.60 (vbr, 4 H, Ph). 13C NMR
(CDCl3): δ 23.9 (CH3), 48.3 (d, J ) 3.1 Hz, C-a), 74.8 (d, J )
3
1
31.7 Hz, C-c), 115.2 (d, J ) 6.0 Hz, C-4), 115.3 (d, J ) 52.1
3
3
Hz, C-2), 120.1 (d, J ) 8.3 Hz, C-6), 128.65 (d, J ) 10.9 Hz,
3
4
C-m), 128.7 (d, J ) 10.7 Hz, C-m′), 130.25 (d, J ) 2.6 Hz,
(29) Apex2, Smart, Saint, and SADABS; Bruker AXS Inc.: Madison,
WI, 2003.
(30) (a) Sheldrick, G. M. SHELXS-97, Program for the Solution of
Crystal Structures; Universita¨t Go¨ttingen, 1997. (b) Sheldrick, G. M.
SHELXL-97, Program for Crystal Structure Refinement; Universita¨t
Go¨ttingen, 1997.
C-p), 130.34 (d, 4J ) 2.6 Hz, C-p′), 132.8 (partly superimposed,
1
2
d, J ≈ 45 Hz, C-i), 132.9 (d, J ) 4.8 Hz, C-b), 133.8 (d, J )
13.1 Hz, C-o), 133.9 (d, 2J ) 13.8 Hz, C-o′), 133.1 (C-3), 133.6
(d, 4J ) 1.8 Hz, C-5), 177.4 (d, 2J ) 21.9 Hz, C-1). 31P{1H}