Synthesis and catalytic activity of allyl, methallyl and methyl complexes of nickel(II) and palladium(II) with biphosphine monoxide ligands: Oligomerization of ethylene and copolymerization of ethylene and carbon monoxide

Article abstract of DOI:10.1016/S1381-1169(99)00449-5

The syntheses of new cationic nickel complexes {[η³- methallyl]Ni[κ²P,O-Ph₂P(X)P(O)Ph₂]}SbF₆, (1)-(2) [X = (oC₆H₄) (1), (NH), (2)] have been accomplished. The complexes oligomerize ethylene to linear α-olefins with selectivities as high as 89%. A dependence of oligomerization grade and activity on backbone geometry was shown. New cationic allyl and methyl complexes of palladium(II) [(CH₃CN)(Me)Pd(κ²P,O- Ar₂P(CH₂)(n)P(O)Ar₂)]X [n = 1-3, X = BF₄, Ar=C₆H₅ (18-20)] [n = 1, X = SbF₆, Ar =p-tolyl (23); n = 1 or 2, X = SbF₆, Ar = C₆H₅ (21) or (22)]; [(ε³,C₃H₅)Pd(κ²P, O-Ph₂P(CH₂)(n)P(O)Ph₂)]X, [n=2, X =triflate (10), tosylate (13); n=3, X =triflate (11), tosylate (14)], [(ε³- C₃H₅)]Pd(κ²P,O-Ar₂P(CH₂)(n)P(O)Ar₂)]X, [n = 1, X = SbF₆, Ar =p-tolyl (17); n = 2, X = SbF₆ Ar = C₆H₅(16)] have been synthesized in good yields. These complexes have been used in the catalytic oligomerization of ethylene, and in the catalytic alternating copolymerization of ethylene and carbon monoxide, to yield polyketones. (C) 2000 Elsevier Science B.V.

Full text of DOI:10.1016/S1381-1169(99)00449-5

Ž
.
Journal of Molecular Catalysis A: Chemical 157 2000 41–58
www.elsevier.comrlocatermolcata
Synthesis and catalytic activity of allyl, methallyl and methyl
ž /
ž /
complexes of nickel II and palladium II with biphosphine
monoxide ligands: oligomerization of ethylene and
copolymerization of ethylene and carbon monoxide
Ingo Brassat a, Wilhelm Keim a, Stefan Killat a, Melanie Mothrath a, Piero Mastrorilli b,
¨
Cosimo Francesco Nobile b, Gian Paolo Suranna b,)
Institut fur Technische Chemie und Petrolchemie der RWTH-Aachen, Worringer Weg 1, D-52074 Aachen, Germany
a
¨
b
Centro di Studi CNR sulle Metodologie InnoÕatiÕe in Sintesi Organiche M.I.S.O., Istituto di Chimica del Politecnico di Bari, Campus
UniÕersitario, Via E. Orabona, 4 I-70126 Bari, Italy
Received 13 August 1999; accepted 8 December 1999
Abstract
3
2
Äw
x
w
Ž . Ž .
x4
Ž . Ž . w
Ž
The syntheses of new cationic nickel complexes h -methallyl Ni k P,O-Ph2P X P O Ph2 SbF6, 1 – 2 Xs o-
. Ž . Ž . Ž .x
C6H4 1 , NH , 2 have been accomplished. The complexes oligomerize ethylene to linear a-olefins with selectivities as
high as 89%. A dependence of oligomerization grade and activity on backbone geometry was shown. New cationic allyl and
2
Ž . wŽ
.Ž
.
Ž
Ž
.
Ž .
.x
w
methyl complexes of palladium II
CH3CN Me Pd k P,O–Ar2P CH2 nP O Ar2
X ns1–3, XsBF4, ArsC6 H5
3
2
Ž
.x w
Ž
.
Ž
.
Ž
Ž
.x wŽ
.
.
Ž
18–20
ns1, XsSbF6, Arsp-tolyl 23 ; ns1 or 2, XsSbF6, ArsC6H5 21 or 22 ; h -C3H5 Pd k P,O-
3
Ž
.
Ž . Ž .x wŽ
.x
w
Ž
.
Ž
.
Ph2P CH2 nP O Ph2 X, n s 2, X s triflate 10 , tosylate 13 ; n s 3, X s triflate 11 , tosylate 14 , h -
2
.x
Ž
Ž
.
Ž .
.x
w
Ž
.
Ž .x
C3H5 Pd k P,O-Ar2P CH2 nP O Ar2 X, ns1, XsSbF6, Arsp-tolyl 17 ; ns2, XsSbF6 ArsC6 H5 16 have
been synthesized in good yields. These complexes have been used in the catalytic oligomerization of ethylene, and in the
catalytic alternating copolymerization of ethylene and carbon monoxide, to yield polyketones. q 2000 Elsevier Science B.V.
All rights reserved.
Keywords: Biphosphine monoxide; Nickel; Palladium; Ethylene oligomerization; Polyketones; EthylenerCO cooligomerization
AbbreÕiations: cod, 1,5-cyclooctadiene; dppacet, o-diphenylphosphino acetophenone; dppanis, o-diphenylphosphino anisole; dppaO,
Ž
.
Ž
.
bis diphenylphosphino amine-monoxide; dppaO2 , bis diphenylphosphino amine-dioxide; dppbald, o-diphenylphosphino benzaldehyde; dpp-
Ž
.
Ž
benzaMe, o-diphenylphosphino benzoic acid methylester; dppeO, 1,2-bis diphenylphosphino ethane-monoxide; dppmO, bis diphenyl-
.
Ž
.
phosphino methane-monoxide; dppOPh, o-diphenylphosphino phenyl-phenylether; dpppaEt, 3-diphenylphosphino propionic acid eth-
Ž
.
Ž
.
Ž
ylester; dppbenzO, 1,2bis diphenylphosphino benzene-monoxide; dpppO, 1,3bis diphenylphosphino propane-monoxide; dppres, 2,5- di-
.
Ž
.
methoxy phenyl-diphenylphosphine; dtolpmO, bis di o-tolylphosphino methane-monoxide; eq., equivalent
)
Corresponding author. Tel.: q0039-80-5963603; fax: q0039-80-5963611.
E-mail address: surannag@cstar.poliba.it G.P. Suranna .
Ž
.
1381-1169r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved.
Ž
.
PII: S1381-1169 99 00449-5

(
)
42
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
1. Introduction
One of the most important applications of
transition metal compounds for industry is their
use as catalysts in oligomerization and poly-
It is widely known that organo-nickel and
-palladium complexes containing phosphine lig-
ands exhibit outstanding catalytic activity in a
large number of organic reactions, e.g.,
w
x
merization of olefins 5,6 . Among the used
metals are the early transition metals, e.g., zir-
conium and titanium, as well as the late transi-
w
x
w
x
carbon–carbon linkage reactions 1,2 .
tion metals like nickel and palladium 7–9 .
Neutral and cationic nickel complexes with
chelating ligands, e.g., P ^O, N ^N, N ^N ^N,
O ^O, have been successfully applied in the
A great interest focuses on the synthesis and
catalytic application of transition metal com-
plexes with chelating ligands containing phos-
Ž
w
x
phorus and oxygen donor atoms in the follow-
oligomerization of olefins 10–14 . Among those
ligands, anionic P ^O-ligands play an important
w x
w x.
ing: P ^O, 3 ; for a review, see Ref. 4 .
Table 1
Ž .
Ž .
Ž .
Ž)
Numbering of the methallyl nickel II , allyl palladium II and methyl palladium II cationic complexes used : new complexes; see Ref.
w
x
.
30 and references therein for other complexes

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
43
w
x
role and are applied in the oligomerization of
diphosphine ligands dppm, dppe, and dppp 30 .
For palladium, it was shown that the coordina-
tion mode of the ligand is dependent on the
backbone and on the anion, revealing a mon-
odentate coordination, when stronger coordinat-
ing anions, such as triflate or tosylate, were
used.
Ž
. w x
ethylene SHOP-process Shell 15 .
The use of cationic nickel complexes with
neutral P ^O-ligands has only been scarcely
w
x
reported in literature 16 .
w
x
Matt et al. 17 synthesized a cationic nickel
complex from a neutral SHOP-like precursor by
protonation of the neutral complex, but no data
for catalytic activity of the cationic complex is
We now want to report on the catalytic activ-
Ž
.
ity exhibited by these complexes Table 1 to-
wards ethylene oligom erization and
ethylenerCO alternating copolymerization and
on the synthesis of some additional new com-
plexes.
w
x
w x
given. Ecke 18 and Schulz 19 reported on the
Ž
.
application of cationic P ^O-chelated nickel
complexes and their catalytic activity in the
oligomerization of olefins. A comparison be-
tween catalytic results of neutral and analogous
cationic complexes showed that the latter ex-
hibits a dramatic increase in activity but has a
lower selectivity to linear and higher a-olefins.
This behaviour was ascribed to a loss of chelate
coordination of the P ^Oligand under catalytic
conditions.
2. Experimental
2.1. Materials and apparatus
All syntheses and catalysis runs were carried
out using standard Schlenk techniques under
argon as inert gas. All solvents were dried and
distilled under argon. Ethylene Gerling and
Holz 99.5% and CO Linde 99.99% were used
as received; AgSbF6 and KPPh2 0.5 M in THF
were purchased from Aldrich; AgCF3SO3 and
Ag p-tolSO3 were purchased from Fluka;
AgBF4 and Celitee were purchased from Fluka.
The ligands dppmO, dtolpmO 31 , and dp-
paO 32 , were prepared according to literature
A polymerization reaction that has recently
risen to industrial application is the alternating
copolymerization of ethylene and carbon
Ž
w
x
. Ž .
monoxide to alternating polyketones 20 .
Polyketone itself is a very interesting polymer
Ž
.
w
x
because of its properties 21 and because of the
w
x
Ž
.
ease of functional group interconversion 22 .
Recent studies have dealt with the mechanistic
explanation of the stereoregularity of this
copolymer, investigating ligand-induced stereo-
w
x
w
x
w
x
w x
control and chain end control 23,24 .
methods; dppeO, dppbenzO, and dpppO 33
w
x
It has also been reported 25 how
cooligomers of ethylene and CO may selec-
were synthesized in a modified way according
to the patent literature given. The comple-
3
Ž .
wŽ
.
Ž .
x w x
tively be obtained using cationic palladium II
xes bis h -methallyl nickel II bromide 34 ,
3
4
Ä
Ž
.Ž .
complexes with P ^O and P ^S ligands. The
effect of hemilabile ligands in catalysis with
h - methallyl h - 1,5 - cyclooctadiene nickel
3
Ž .
4
w
x
w
Ž
.
II hexafluoroantimonate 35 , bis h -allyl
x w .
palladium II iodide 36 , and chloro methyl
h -1,5-cyclooctadiene palladium II 37 , were
Ž .
Ž .
Ž .
x
wŽ
.Ž
nickel II and palladium II complexes, and the
possible mechanistic activation pathways, have
4
Ž
.
Ž .x w
x
w
x
been elucidated by several studies 26–28 .
synthesized according to the literature.
Ž .
Polymerization, catalyzed by palladium II
Gas-chromatograms were obtained on
Siemens Synchromat systems equipped with a
25-m SE 54-CS column using nitrogen as car-
rier gas, or with a 100-m Pona CB using helium
as carrier gas. Yields of ethylene oligomers
were obtained with the use of the internal stan-
methyl complexes with P ^O, N ^O, and triden-
tate P ^N ^O ligands, has also been described
w
x
29 .
We previously have reported on the synthesis
Ž .
and characterization of cationic nickel II and
Ž .
Ž .
palladium II complexes with the monoxides of
dard method nonane . The molecular weights

(
)
44
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
of the alternating copolymers were determined
by GPC using HFIPA as eluent. A typical GPC
probe contained 10 mg of polymer dissolved in
2 ml solvent.
brown suspension is stirred for 30 min. Silver
bromide, precipitating after the addition of a
solution of AgSbF6 in 5 ml of dichloromethane,
is filtered off through Celitee after a maximum
reaction time of 5 min. The clear yellow filtrate
is collected at y208C. The solvent is removed
in vacuo, yielding a yellow powder that is
washed with diethylether and n-pentane. After
drying in vacuo, the complexes are obtained in
analytically pure form. Scales and yields are
given in Table 2. Analytical data for the new
complexes are given in Section 2.3. All data for
other complexes have been previously reported
NMR spectra in solution were recorded on a
Bruker DPX 300 or a Bruker AM-300 instru-
ment; 13C MAS CP NMR spectra were recorded
on a Bruker AM-300 Spectrometer. The num-
bering of the allylrmethallyl ligand in NMR
1
5
1Ž
.
2Ž
.
2Ž
data is as follows: H syn H anti -C C H
for allyl, Me for the CH3 group of methallyl
.
1
4Ž
.
3Ž
.
3
C H syn H anti . C is trans to P.
31P NMR chemical shifts relative to 85%
phosphoric acid are reported with positive val-
ues downfield from the reference. IR spectra
were recorded on a Nicolet 510 P FT spectrom-
eter. The samples were prepared as a Nujol mull
and placed between KBr plates or as CH2Cl2
solutions between KBr plates. Secondary ion
w
x
30 .
3
(
)[
2.2.2. Syntheses of complexes h -allyl bis-
1
2
(
)
diarylphosphino alkane - monoxide-k - Prk -
]
( ) ) ( ) ( ) ( )
(
P,O palladium II anion 10 , 11 , 13 , 14 ,
) (
Ž
.
(
)
mass spectrograms SIMS were obtained on a
Finnigan MAT 95 spectrometer with the follow-
16 , 17
To a solution of h -allyl bis diarylphos-
3
Ä
Ž
.
w
Ž
1
Ž
.
. xŽ .
ing matrixes: 3-nitrobenzylalcohol NBA ; a
mixture of 1,4-dithio-DL-threitol; 1,4-dithio-
phino alkane-monoxide-k - P iodo palladium
Ž .
4
II in a 5 ml of dichloromethane, 1.0 eq. of
silver salt in dichloromethane is added at room
temperature. Precipitation of silver iodide oc-
curs immediately, and the mixture is stirred for
a maximum reaction time of 5 min. It is then
filtered through Celitee and the clear, colour-
less, or pale yellow filtrate solution is evapo-
rated to about 2 ml. By adding 15 ml of n-pen-
tane, an off-white or pale-yellow solid precipi-
tates. The complexes 10, 11, 13, 14, 16 and 17
can be obtained as powders in analytically pure
form after the decanting from the solvent and
the drying in vacuo. Scales and yields are given
in Table 3. Analytical data for the new com-
plexes are given in Section 2.3. All of the data
Ž
.
erythritol; sulfolane DTTrDTErSul or a 10:1
mixture of 18-crown-6rtetraethyleneglycoldi-
Ž
.
methylether KrT . Elemental analyses were
performed on a Carlo Erba 1106 CHN analyser.
2.2. Complex synthesis
3
(
)
2.2.1. Synthesis of complexes h -methallyl
2
[
( )
]
( )
P ^P O -k -P,O nickel II anion 1–2
To a suspension of about 0.5 mmol h -
methallyl NiBr in 10 ml dichloromethane at
3
w
Ž
.
x
2
y208C, a solution of 2.0 eq. of the biphosphine
monoxide in 5 ml of the same solvent is added
while stirring vigorously. The resulting red-
Table 2
Scales and yields for the preparation of complexes 1 and 2
3
wŽ
.
x
Number
Ligand
mg and mmol
h -C4 H7 NiBr 2
AgSbF6
Yield
1
dppbenzO
716 mg
294 mg
522 mg
1.12 g
Ž
.
1.55 mmol
536 mg
1.34 mmol
0.76 mmol
235 mg
0.606 mmol
1.52 mmol
417 mg
1.21 mmol
1.38 mmol 91 %
0.80 g
Ž .
dppaOrdppaO2 mixture
2
Ž .
1.06 mmol 88%

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
45
Table 3
Scales and yields for the preparation of complexes 10, 11, 13, 14a
3
wŽ
.
x
Complex
Ligand
dppeO
mg and mmol
h -C3H5 PdI
AgX
Yield
2
Ž
.
10
396 mg
0.956 mmol
343 mg
0.8 mmol
380 mg
0.917 mmol
342 mg
261.1 mg
0.476 mmol
219 mg
0.4 mmol
251 mg
244.7 mg triflate
0.952 mmol
206 mg triflate
0.8 mmol
260 mg tosylate
0.932 mmol
223 mg tosylate
604.3 mg
0.85 mmol 89%
510 mg
0.7 mmol 88%
520 mg
0.709 mmol 78%
500 mg
Ž
.
Ž
.
11
13
14
dpppO
dppeO
dpppO
Ž
.
Ž
.
Ž
.
0.457 mmol
219 mg
Ž
.
Ž .
0.67 mmol 84%
0.8 mmol
0.4 mmol
0.8 mmol
aComplexes 16 and 17 were prepared according to literature methods 30 ; these complexes show the same analytical data for the
w
x
organometallic cation with respect to their analogues bearing BF4y as the counteranion.
for other complexes have been previously re-
is evaporated to about 2 ml. By adding 15 ml of
n-pentane, a white solid precipitates. Complexes
18–23 can be obtained as powders in analyti-
cally pure form after the decanting from the
solvent and the drying in vacuo. Scales and
yields are given in Table 4. Analytical data for
the new complexes are given in Section 2.3.
w
x
ported 30 .
[(
)
Me Pd-
2.2.3. Synthesis of complexes
(
( ))(
)]
( ) ( ) ( ) ( )
P ^P O CH3CN anion 18 , 19 , 20 , 21 ,
(
) (
)
22 , 23
2
w
Ž
.Ž
.
Ž
Ž .
To a solution of Cl Me Pd P ^P O -k -
1
.
x
w
Ž
.Ž
.
Ž
Ž .
.x
P,O or Cl Me Pd P ^P O -k -P in 5 ml
2
of dichloromethane and 1 ml of acetonitrile
2.3. Spectroscopic properties
Ž
.
excess , 1.0 eq. of silver salt in dichloromethane
3
{
(
)[
(
or dichloromethaneracetonitrile is added at
room temperature. Precipitation of silver chlo-
ride occurs immediately, and the mixture is
stirred for a maximum reaction time of 5 min.
The mixture is filtered through Celitee, and the
clear, colourless, or pale-yellow filtrate solution
2.3.1.
h -Methallyl 1,2-bis diphenylphos-
2
)
]
( )
)
}
(
phino benzene-monoxide-k - P,O nickel II he-
3
[(
xafluoroantimonate,
)] ( )
h -methallyl Ni dp-
pbenzO SbF6
1
Ž
.
Anal. Calc. for C34H31F6NiOP2Sb 812.04 :
C, 50.29; H, 3.86. Found: C, 49.91; H, 4.19. H
1
Table 4
Scales and yields for the preparation of complexes 18–23
Ž
.
Ž
.
Complex
Ligand
P ^PO Pd CH3 Cl or
wÄŽ .Ž
AgX
Yield
1
.
Ž
Ž
.
.4 x
m-Cl Me Pd P ^P O -k P
2
18
19
20a
21
22
23
dppmO
dppeO
736 mg
1.32 mmol
137 mg
0.24 mmol
156 mg
0.26 mmol
796 mgb
1.24 mmol
194.9 mg
0.341 mmol
394.2 mg
0.643 mmol
263 mg
1.35 mmol XsBF4
48 mg
0.25 mmol XsBF4
51.6 mg
0.26 mmol XsBF4
440.5 mg
1.28 mmol XsSbF6
118.4 mg
0.345 mmol XsSbF6
226.0 mg
770 mg
1.19 mmol 90%
147 mg
0.22 mmol 92%
147 mg
0.22 mmol 85%
770.1 mg
0.96 mmol 77%
247.7 mg
0.305 mmol 89%
519.3 mg
Ž
0.608 mmol 94%
Ž
.
.
.
.
Ž
dpppO
dppmO
dppeO
Ž
Ž
Ž
.
.
dtolpmO
0.658 mmol XsSbF6
a
Ž
.
In the presence of excess acetonitrile 0.15 ml .
b
Ž
.
Ž
.
Ž
.
Complex: dppmO Pd CH3 ClPCH2Cl2 crystalline .

(
)
46
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
3
Ž
.
w
x
(
)[
(
)
NMR CD2Cl2, 300 MHz, 293 K : ppm ds
2.3.3. h -Allyl 1,2-bis diphenylphosphino -
1
2
2
Ž
.
Ž
.
Ž
]
[(
( )
(
1.68 s, 1H, H , 1.99 s, 1H, H , 2.19 s, 3H,
Me , 3.60 s br, 1H, H , 4.34 s br, 1H, H ,
7.00–8.50 m, 24H, Ar . .
ethane-monoxide-k -P,O palladium II trifluo-
romethanesulfonate
CF3SO3 10
Anal. Calc. for C30H29F3O4P2 PdS 710.98 :
C, 50.68; H, 4.11. Found: C, 50.74; H, 4.24. H
NMR: CD2Cl2, 300 MHz, 293 K : ppm ds
2.30–2.45 vbr, 2H, H , 2.69–2.89 br d,
3
4
3
.
Ž
.
Ž
.
)
)]
h -allyl Pd dppeO -
13
1
Ž
. .
Ä 4
C H NMR
x
(
)
Ž
.
w
Ž
Ž
.
CD2Cl2, 75 MHz, 293 K : ppm ds23.3 s,
1
3
.
Ž
.
Ž
Me , 49.4 d, Js3.8 Hz, C , 77.8 d, Js18.5
31
1
1
2
.
Ž
.
w
Ä
4
Ž
.
w
x
Hz, C , 127.4–136.6 C qCarom
.
P H
x
3,4
Ž
.
Ž
.
Ž
NMR CD2Cl2, 121 MHz, 293 K : ppm ds
Ž
.
Ž
.
Ž
16.4 d, Js28.1 Hz, PPh2 , 47.3 d, Js28.1
Js10.5 Hz, 4H, CH2CH2 , 4.12 dd, Js9.3
y
1
2
Ž .
.
Ž
.
w
x
ns1461 vs,
.
Ž
Hz, P O Ph2 ; IR Nujol : cm
Hz, Js13.8 Hz, 1H, H , 5.08 t, JH,H sJH,P
1
5
.
Ž
.
1377 vs, 1306 w, 1146 w, 1120 m, 1083 w,
1051 w, 1027 w, 738 m, 723 m, 656 s, 546 m.
s6.9 Hz, 1H, H , 5.85 m, 1H, H , 7.48–7.87
31
1
Ž
.
Ä 4 Ž
P H NMR: CD2Cl2, 121
m, 20H, Harom
.
Ž
.
w
Ž
.
x
Ž
Ž
.
.
w
x
Ž
SIMS NBA , cation: mrz Irel. % s575 100
MHz, 293 K : ppm ds20.7 d, Js11.7 Hz,
19
1
w
Ž
.
Ž
.
xq
.
w
Ž
Ž
.
Ž
Ž .
.
Ä
4
methallyl Ni dppbenzO , 520 19 Ni dp-
PPh2 , 47.9 d, Js11.7 Hz, P O Ph2 . F H
.
xq
Ž .
Ž
.
Ž
Ž .
.
Ž
.
w
x
pbenzO , 401 4 , 385 24 , 281 5 , 73 89 ;
NMR CD2Cl2, 282 MHz, 293 K : ppm ds
Ž
.
.
w
xy
anion: mrz Irel.r% s235 100 SbF6 .
Ž .
Ž
.
y79.19 s . SIMS DTTrDTErSul , cation:
mrz Irel. % s561 28 all Pd dppeO q, 520
w
Ž
.
x
Ž
.
w
Ž
.
Ž
.x
Ž .
w
Ž
w
.
xq xq
Ž
.
w
Ž
.
2
Pd dppeO , 447 29 dppeO qSH ,
3
Ž .
Ž
.
xq
Ž
.
w
Ž
.
(
)[
(
]
) (
)
2.3.2. h -Methallyl bis diphenylphosphino -
amine-monoxide-k - P,O nickel II hexafluoro-
antimonate, h -methallyl Ni dppaO SbF6
Anal. Calc. for C28H28F6NNiOP2Sb 750.9 :
C, 44.78; H, 3.77; N, 1.87. Found: C, 44.76; H,
3.92; N, 1.89. H NMR CD2Cl2, 300 MHz,
443 7 Pd dppeO –Ph , 415 19 dppeO q
2
xq
25
Ž .
Ž
.
Ž .
w
,
xq
( )
H , 368 3 , 337 10 , 291 4 Ph2 PPd , 229
3
Ž
.
w
Ž
.
xq
Ž
.
[(
)]
( )
2
Ph 2 P O CH 2 CH 2
Ph2 PCH2CH2 , 201 4 Ph2 PO , 185 4
213
14
Ž .
Ž
.
w
xq
Ž .
w
xq
w
xq
Ž
.
w
Ž
.
x
Ph2 P , 133 100 ; anion: mrz Irel. % s149
1
Ž
Ž
.
w
xy
100 CF3SO3 .
.
w
.
x
Ž
.
Ž
293 K : ppm ds2.17 s, 3H, Me , 5.74 br s,
3
Ž
. Ž
(
)[(
(
)
1H, NH 6.50–8.50 m, 20H, Ar the reso-
2.3.4. h -Allyl 1,3-bis diphenylphosphino -
propane-monoxide-k 1,2-P,O palladium II tri-
)
( )
nances of allylic protons are broadened at 293 K
due to fluctuation . H NMR CD2Cl2, 300
MHz, 267 K : ppm ds1.80 s, 1H, H , 2.17
s, 3H, Me , 2.67 br s, 1H, H , 3.41 m, 1H,
H , 4.41 s, 1H, H , 5.74 br s, 1H, NH ,
6.50–8.50 m, 20H, Ar .
CD2Cl2, 75 MHz, 293 K : ppm ds22.3 s,
Me , 126.2–133.6 Carom the resonances of
1
3
.
Ž
[(
)
(
)]
fluoromethanesulfonate h -allyl Pd dpppO -
CF3SO3 11
Anal. Calc. for C31H31F3O4P2 PdS: C, 51.36;
H, 4.31. Found: C, 50.30; H: 4.30. H NMR
CD2Cl2, 300 MHz : most abundant isomer k
P,O coordination , ppm ds1.97–1.50 m, 2H,
CH2 , 3.19–2.53 m, 6H, Ph2 P-O CH2,
1
.
w
x
Ž
.
(
)
2
Ž
.
Ž
Ž
.
Ž
1
3
4
.
.
Ž
.
13
1
2
Ž
.
Ä 4
C H NMR
x
Ž
.
Ž
Ž
.
w
Ž
.
w
x
Ž
.
Ž
. Ž
.
Ž
Ž
.
4
3
1
2
.
Ž
.
Ž
allylic carbon atoms are broadened at 293 K due
to fluctuation . P H NMR CD2Cl2, 121
CH2 PPh2, H , H , 3.67 dd, 1H, H , 4.50 t,
1H, H , 5.75–5.64 m, 1H, H , 7.83–7.00 m,
31
1
1
5
.
Ä
x
4
Ž
.
Ž
.
Ž
13
1
.
w
Ž
.
Ä
4
Ž
.
MHz, 293 K : ppm ds65.7 d, Js27.0 Hz,
20H, Harom
.
C H NMR CDCl3, 75 MHz :
2
.
Ž
Ž .
.
Ž
.
PPh2 , 71.5 d, Js27.0 Hz, P O Ph2 . IR
most abundant isomer, k P,O coordination
ppm ds13.5 CH2 , 27.6–25.2 m, Ph2
P-O CH2, CH2 PPh2 , 52.2 C , 81.0 d, J
y
1
Ž
.
w
x
`
Ž
w
Ž
Ž
Ž
x
Ž
.
Ž
Nujol : cm
ns1463 vs, 1439 m, 1377 s,
2
3
.
.
Ž
.
1258 m, 1130 s, 1104 m, 1077 m, 1067 m, 899
vs, 734 m, 693 m, 658 vs, 532 s. SIMS NBA ,
cation: m r z
m eth ally N i d p p aO
HNi dppaO , 281 5 , 221 4 , 207 9 , 147
18 , 90 10 , 73 100 ; anion: mrz Irel. % s
235 100 SbF6
1
2
Ž
.
.
.
Ž
.
C,P s31 Hz, C , 119.1 s, C , 132.3–126.3
31
w
Ž
.
x
Ž
.
.
Ž . Ž .
P NMR CDCl3, 121 MHz : a most
Irel.
%
.
s 514
31
1 2
Carom
.
w
w
Ž
Ž
.
Ž
xq
Ž
.
,
4 6 0
Ž
.
.
xq
Ž .
.
Ž .
Ž .
1 The chemical shift of the allylic protons H4, H3 was deter-
.
Ž
. w
Ž
w
Ž .x
Ž
.
mined with the aid of H,H-COSY in CDCl3 as: d s3.1 ppm
xy
4
3
Ž
.
Ž
H
.
Ž
.
, d s2.9 ppm H .

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
47
2
Ž
.
w
x
Ž
.
w
x
Ž
abundant isomer k P,O coordination : ppm
CDCl3, 300 MHz : ppm ds1.81 s, broad,
`
`
Ž
.
Ž
. Ž .
`
.
Ž
Ž
.
ds16.5
PPh2 , 51.2
Ph2 P-O , b less
2H, CH2 , 2.64–2.19 m, 8H, Ph2 P-O CH2,
1
2
4
CH2 PPh2, H3, CH3 , 3.50 s,broad 1H, H ,
Ž
.
w
x
`
.
.
Ž
.
abundant isomer k P coordination : ppm d
19
2
1
`
`
Ž
.
Ž
.
Ž
Ž
Ž
.
s17.7
PPh2 , 35.0
Ph2 P-O . F CD-
3.81 dd, 1H, H , 4.90 t, 1H, H , 5.50–5.19
5
.
w
x
Ž
.
Ž
.
Ž
.
Cl3, 282 MHz : ppm dsy78.5 CF3SO3y
.
.
.
x
.
m, 1H, H , 6.97–7.80 m, 20H, Harom .
C H NMR CDCl3, 75 MHz : ppm ds
13
1
IR nujol mull : ns1146.4 P-O cmy
1
Ž
.
Ž
.
Ä
4
Ž
.
w
x
w
Ž
.
x
Ž
`
Ž
Ž
.
Ž
Ž
.
SIMS, cation: mrz Irel. % s575.3 75.44
13.5 CH2 , 27.6–25.2 m, Ph2 P-O CH2,
3
w
Ž
.
Ž
Ž
.
xq
Ž
.
w
.
Ž
.
Ž
.
all Pd dpppO ; 461.2 88.75 dpppOqSH ,
CH2 PPh2 , 52.2 C , 81.0 d, 2 J C,P s31
1
2
.
w
x
.
Ž
.
Ž
.
Ž
.
429.2 100
dpppO q H , 243.2 46.76
Hz, C , 119.1 s, C , 126.3–132.3 Carom .
31
1
w
x
Ž
w
x
Ä
4
Ž
.
w
x
Ž
Ph2 POC3H6 , 201,0 83.12 Ph2 PO . SIMS,
P H NMR CDCl3, 121 MHz : ppm ds
w
Ž
.
x
Ž
.
w
xy
`
`
Ž
PPh2 , 35.1
Ž
.
.
anion: mrz Irel. % s149 100 CF3SO3
.
21.78
Ph2yP-O . IR nujol
1
.
Ž
.
mull : ns1146.4 P-O cm
.
.
w
Ž
x
Ž
.
SIMS, cation: mrz Irel. % s575 38.5
3
{
(
)[
(
)
2.3.5.
h -Allyl 1,2-bis diphenylphosphino -
wŽ
.
Ž
Ž
.
xq
w
Ž
.
w
x
all Pd dpppO ; 461 100.0 dpppOqSH ,
2
]
( )} (
ethane-monoxide-k -P,O palladium II tolyl-
.
x
Ž
.
429 71.7
dpppO q H , 243 32.7
3
) [( )
)
(
)](
4-sulfonate
h -allyl Pd dppeO p-tolSO3
w
x
Ž
.
w
x
Ž
.
Ph2 POC3H6 , 201.0 50.9 Ph2PO , 147 37.2
(
)
13
Anal. Calc. for C36H36O4P2 PdS 733.10 : C,
58.93; H, 4.95. Found: C, 57.81; H, 5.17. H
w
x
w
Ž .x
C3H5Pd ; SIMS, anion: mrz Irel. % s171
Ž
.
1
Ž
. w
xy
100 p-H3C–C6H4–SO3
.
Ž
.
w
x
NMR CDCl3, 300 MHz, 293 K : ppm ds
[
(
)
2.3.7. Bis diphenylphosphino methane-mono-
Ž
.
Ž
2.34 s, 3H, CH3 , 2.65–3.00 br m, 6H,
2
]( ( )
)(
)
xide-k -P,O acetonitrile methyl palladium II
tetrafluoroborate 18
Anal. Calc. For C28H28BF4NOP2 Pd 649.70 :
C, 51.76; H, 4.34; N, 2.16. Found: C, 47.20; H,
X
CH2CH2, H3,4 , 4.04 dd, J s9.3 Hz, J0s
.
Ž
(
)
2
.
Ž
14.1 Hz, 1H, H , 5.19 t, JH,H sJH,P s6.9 Hz,
Ž
.
1
5
.
Ž
.
Ž
1H, H , 5.61 m, 1H, H , 7.08–7.76 m, 24H,
31
1
.
Ä 4 Ž
Harom
.
P H NMR CDCl3, 121 MHz, 293
1
Ž
4.24; N, 2.13. H NMR CDCl3, 300 MHz, 293
.
w
x
Ž
.
.
K : ppm ds22.6 d, Js49.1 Hz, PPh2 ,
.
w
x
Ž
.
K : ppm ds0.55 d, Js2.1 Hz, 3H, PdCH3 ,
Ž
Ž .
.
Ž
36.0 d, Js49.1 Hz, P O Ph2 . IR CH2Cl2 :
Ž
.
Ž
2.30 s, 3H, NCCH3 , 3.71 dd, Js9.6 Hz,
y
1
w
x
ns3048 w, 2979 w, 1438 m, 1213 m,
cm
.
Ž
Js11.7 Hz, 2H, CH2 , 7.20–7.38 m, 12H,
1191 s, 1131 m, 1122 m, 1103 m, 1046 m, 1016
.
Ž
.
Harom , 7.46–7.53 m, 4H, Harom , 7.67–7.71
Ž
.
w, 741 s, 730 s, 695 s. SIMS DTTrDTErSul ,
13
1
Ž
.
Ä 4 Ž
m, 4H, Harom
. C H NMR CDCl3, 75 MHz,
w
Ž
.
x
Ž
.
w
Ž
. Ž
all Pd dp-
cation: mrz Irel. % s561 20
.
w
x
Ž
293 K : ppm dsy3.2 d, Js4.2 Hz,
.
xq
Ž .
w
Ž
.
xq
Ž
. wŽ
peO , 520 3 Pd dppeO , 447 100 dp-
.
Ž
.
Ž
PdCH3 , 2.7 s, NCCH3 , 33.9 dd, Js18.7
`
.
xq
Ž .
w
Ž
.
xq
peO qSH , 443 8 Pd dppeO Ph , 415
.
Ž
Ž
.
Hz, J s 64.6 Hz, CH2 , 118.9 NCCH3 ,
Ž
.
w
Ž
.
xq
Ž .
Ž
.
Ž .
27 dppeO qH , 369 7 , 337 21 , 291 5
Ž
.
.
126.5–128.9 Cipso,arom , 129.0–133.5 CHarom
.
x
Ph2 PPd , 229 73 Ph2 P O CH2CH2 q, 213
xq xq
w
xq
Ž
.
w
Ž .
x
31
1
Ä
4
Ž
.
w
P H NMR CDCl3, 121 MHz, 293 K : ppm
ds31.4 d, Js15.0 Hz, PPh2 , 52.3 d, Js
15.0 Hz, P O Ph2 . F H NMR CDCl3, 282
Ž
Ž .
.
w
Ž
. w
31 Ph2 PCH2CH2 , 201 11 Ph2 PO , 185
Ž
.
Ž
w
xq
Ž .
Ph2 P . SIMS DTTrDTErSul , anion:
8
19
1
Ž .
.
w
Ä
4
Ž
w
Ž
.
x
Ž
.
w
mrz Irel. % s171 100
p–H3C–C6H4–
.
x
Ž
.
MHz, 293 K : ppm dsy152.71 s, 1F ,
xy
SO3
.
Ž
.
y152.60 s, 3F .
The complexes 15, 16 and 17 show the same
1H, 13C and 31P data as their analogues bearing
tetrafluoroborate as counteranion.
3
(
)[(
(
)
2.3.6. h -Allyl 1,3-bis diphenylphosphino -
propane-monoxide-k 1 P palladium II tolyl-
y
)
( ) (
)](
3
) [(
)
(
)
4-sulfonate
h -allyl Pd dpppO p-tolSO3
(
)
14
Anal. Calc. for C37H38O4P2 PdS: C, 59.48;
2 The chemical shift of the allylic proton H3 was determined
1
3
H, 5.13. Found: C, 56.93; H, 5.15. H NMR
Ž
.
Ž
.
.
with the aid of H,H-COSY in CDCl3 as: d s2.45 ppm H

(
)
48
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
13
1
[
(
] (
)
Ä
4
Ž
.
w
x
2.3.8. 1,2-Bis diphenylphosphino ethane-
C H NMR CDCl3, 75 MHz : ppm ds
2
) (
)
Ž
.
Ž
.
monoxide-k -P,O acetonitrile methyl palla-
( ) ( )
dium II tetrafluoroborate 19
Anal. Calc. for C29H30BF4NOP2 Pd 663.73 :
C, 52.48; H, 4.56; N, 2.11. Found: C, 51.03; H,
y3.2 d, JC,P s4.2 Hz, PdCH3 , 2.7 NCCH3 ,
Ž
33.3 dd, JC,P s18.6 Hz, JC,PO s64.6 Hz,
Ž
.
.
Ž
.
Ž
.
CH2 , 118.9 NCCH3 , 126.5–128.9 Cipso
,
31
1
Ž
.
Ä
4
Ž
129.0–133.5 CHarom
.
P H NMR CDCl3,
1
Ž
.
w
x
Ž
4.88; N, 1.55. H NMR CDCl3, 300 MHz, 293
121 MHz : ppm ds31.39 d, JP,P s15.0 Hz,
.
w
x
Ž
.
.
Ž
.
Ž
K : ppm ds0.37 d, Js2.1 Hz, 3H, PdCH3 ,
P , 52.32 d, JP,P s15.0 Hz, PO . IR nujol
mull : ns1137.0 P-O, vs cmy1. SIMS
Ž
.
Ž
.
Ž
.
2.18 s, 3H, NCCH3 , 2.49–2.66 br m, 4H,
.
Ž
.
Ž
.
w
Ž
.
.
x
Ž
. wŽ
CH2CH2 , 7.37–7.58 m, 16H, Harom , 7.68–
NBA , cation: mrz Irel. % s521 100 dp-
13
1
xq xq
Ž
w
Ž
.
dppmO Pd , 305
Ž
.
Ä
4
Ž
.
7.77 m, 4H, Harom
.
C H NMR CDCl3, 75
pmO PdCH3 , 506 18
Ž
Ž
w
.
.
w
Ž
.
xq
Ž .
.
w
xq
201
Ž .
.
Ž
w
x
Ž
MHz, 293 K : ppm dsy1.4 d, Js2,51 Hz,
28 Ph2 PCH2 Pd , 291 7 Ph2 PPd , 277
14 , 215
Ph2 PO , 199 5 Ph2 PCH2 , 183 6 , 147
xq
Ž .
5
.
.
Ž
Ž .
w
Ž
PdCH3 , 2.6 s, NCCH3 , 20.5 dd, Js5.3 Hz,
5
Ph2 P O CH 2
,
xq
Ž .
w
xq
.
Ž
Js31.1 Hz, CH2 P , 24.0 d, Js68.0 Hz,
Ž
..
Ž
.
Ž
.
Ž
.
w
Ž .x
CH2 P O , 117.8 NCCH3 , 127.4–129.5
11 . SIMS NBA , anion: mrz Irel. % s235
31
1
xy
100 SbF6 .
Ž
.
Ž
.
w
Ä
4
Ž
.
w
Cipso,arom , 129.2–133.4 CHarom
.
P H
x
Ž
.
NMR CDCl3, 121 MHz, 293 K : ppm ds
Ž
.
Ž
Ž .
.
[
(
] (
)
35.7 d, Js8.7 Hz, PPh2 , 44.2 br, P O Ph2 .
2.3.11. 1,2-Bis diphenylphosphino ethane-
monoxide-k -P,O acetonitrile methyl palla-
dium II hexafluoroantimonate 22
19
1
2
Ä
4
Ž
Ž
.
w
x
) (
)
F H NMR CDCl3, 282 MHz, 293 K : ppm
.
Ž
.
( ) ( )
H NMR CDCl3, 300 MHz : ppm ds0.38
dsy153.72 s, 1F , y153.77 s, 3F .
1
Ž
.
w
x
[
(
)
Ž
.
Ž
2.3.9. 1,3-Bis diphenylphosphino propane-
d, JH,P s2.4 Hz, 3H, PdCH3 , 2.26 s, 3H,
2
](
) (
)
.
Ž
.
.
monoxide-k - P,O acetonitrile methyl palla-
dium II tetrafluoroborate 20
H NMR CDCl3, 300 MHz : ppm ds
0.442 s, 3H, CH3 , 1.65 br, 2H, CH2 , 2.07 s,
3H, CH3CN , 2.45 br, 2H, CH2 PPh2 , 2.69
br, 2H, CH2 , 7.19–7.75 m, 20H, Harom .
C H NMR CDCl3, 75 MHz, : ppm ds
129.4–133.6 Carom , 106 s, CH3CN , 26.9
NCCH3 , 2.42–2.55 m, 4H, CH2CH2 , 7.40–
13
1
( )
(
)
Ž
.
Ä
4
Ž
7.70 m, 20H, Harom
C H NMR CDCl3,
1
Ž
.
w
x
.
w
x
Ž
75 MHz : ppm dsy1.4 d, JC,P s2.5 Hz,
Ž
.
Ž
.
Ž
.
Ž
.
Ž
PdCH3 , 2.6 NCCH3 , 20.5 dd, JC,P s30.8
.
Ž
.
.
Ž
Hz, JC,PO s5.0 Hz, PCH2 , 23.1 d, JC,PO
s
Ž
.
Ž
.
Ž .
.
.
Ž
Ž
.
.
68.0 Hz, P O CH2 , 117.8 NCCH3 , 127.4–
13
1
31
1
Ä
4
Ž
.
w
x
Ž
Ž
.
Ä
4
128.1 Cipso , 129.2–133.4 CHarom
P H
Ž
.
Ž
.
.
w
x
Ž
NMR CDCl3, 121 MHz : ppm ds35.88 d,
Ž
Ž
Ž
Ž
.
.
Ž
.
.
Ž
.
Ž
Ph2 P-O CH2, CH2 PPh2 , 17.2 CH2 , 2.78
JP,P s3.5 Hz, P , 45.34 br s, PO . IR nujol
31
1
mull : ns1158.3, 1125.0 P-O, s cmy
.
1
`
.
Ž
.
Ä
4
.
Ž
.
s, CH3CN , y1
CH3 .
P H NMR
`
.
Ž
.
.
Ž
.
w
Ž
.
x
Ž .
CD2Cl2, 121 MHz, : ds49.76
Ph2 P-O ,
SIMS NBA , cation: mrz Irel. % s535 3
19
`
Ž
.
Ž
w
Ž
.
xq
Ž .
Ž
Ž
Ž
.
Ž .
Ž
Ž
.
30.11 PPh2 ; F NMR CDCl3, 282 MHz, :
dppeO PdCH3 , 327 11 , 325 8 , 281 21 ,
y
Ž
.
Ž
.
Ž .
Ž
Ž
Ž
.
Ž
.
.
dsy153.6 BF4 . IR nujol mull : ns1153.8
277 9 , 267 9 , 221 20 , 207 37 , 193 10 ,
y
1
Ž
.
Ž
.
.
.
Ž
.
P-O cm . SIMS DTTrDTErSUL cation:
147 100 , 136 53 . SIMS NBA , anion: mrz
q
w
.
x
. w
xy
w
Ž
.
x
Ž
.
.
mrz Irel.. % s 549 M –CH 3CN–BF4 .
Irel. % s235 100 SbF6
.
Ž
w
Ž .x
SIMS DTTrDTErSUL : mrz Irel. % s
Ž
. w
xy
[
(
)
87 100 BF4
.
2.3.12. Bis di-o-tolylphosphino methane-mono-
xide-k -P,O acetonitrile methyl palladium II
2
]( ( )
)(
)
[
(
)
(
)
2.3.10. Bis diphenylphosphino methane-mono-
hexafluoroantimonate 23
1
2
]( ( )
)(
)
Ž
.
w
x
xide-k -P,O acetonitrile methyl palladium II
hexafluoroantimonate 21
H NMR CDCl3, 300 MHz : ppm ds0.51
(
)
Ž
.
Ž
d, JH,P s2.1 Hz, 3H, PdCH3 , 2.26, 2.27 s,
1
Ž
.
w
x
.
Ž
.
Ž
H NMR CDCl3, 300 MHz : ppm ds0.55
12H, CH3 , 2.28 s, 3H, NCCH3 , 3.42 br m,
13
1
Ž
.
Ž
.
Ž
.
Ä
4
d, JH,P s2.1 Hz, 3H, PdCH3 , 2.30 s, 3H,
2H, CH2 , 7.04–7.47 m, 16H, Harom
.
C H
.
Ž
.
Ž
.
.
w
x
NCCH3 , 3.72 dd, JH,P s9.6 Hz, JH,PO s11.7
NMR CDCl3, 75 MHz : ppm dsy3.0
PdCH3 , 2.6 NCCH3 , 34.5 dd, JC,P s18.7
Ž
.
Ž
Ž
.
Ž
Hz, 2H, CH2 , 7.25–7.71 m, 20H, Harom .

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
49
.
Ž
.
Hz, JC,PO s66.0 Hz, CH2 , 119.0 NCCH3 ,
inlet and a Teflone-coated magnetic stirring
bar.
In a typical experiment, 0.1 mmol of the
catalyst was dissolved in 10 ml of
dichloromethane, and the resulting solution was
Ž
.
Ž
.
123.2–126.1 Cipso , 129.8–133.2 CHarom ,
31
1
Ž
.
Ä
4
Ž
142.6, 144.1 Cipso
.
P H NMR CDCl3, 121
.
w
x
Ž
.
MHz : ppm ds29.70 d, JP,P s14.6 Hz, P ,
Ž
.
Ž
.
52.22 br s, PO . IR nujol mull : ns1136.3,
y
1
Ž
.
Ž
.
Ž
1123.2 P-O, s cm . SIMS NBA , cation:
transferred to the autoclave inlet. Ethylene 30
xq
.
`
w
Ž
.
x
Ž
.
Ž
w
mrz Irel. % s577 100 M CH3CN , 562
bars , followed by CO, were pressed into the
Ž
.
w
Ž
.
xq
.
w
Ž
.
xq
Ž .
13 Pd dtolpmO , 333 35 tol PCH2 Pd ,
system for 5 min each, then the autoclave was
heated to the desired temperature. After cataly-
sis, the autoclave was cooled in an ice bath to
quench the reaction. The polymer was isolated,
washed with dichloromethane, dried and
weighted. Chemical yield and TON of the cata-
lyst were determined, TON as moles of con-
2
Ž
.
w
Ž
.
xq
Ž .
319 30
tol PPd , 245 7 , 243 7
2
w
Ž
.
Ž .
xq
Ž
.
w
Ž
.
xq
tol P O CH2 , 229 11
tol PO , 227
2
Ž . w2
Ž
.
xq
Ž
.
7
tol PCH2 . SIMS NBA , anion: mrz
w
Ž
.
x 2
Ž
.
w
xy
Irel. % s235 100 SbF6
.
2.4. Catalytic runs: ethylene oligomerization
w
Ž
.x
verted substrate mpolymerr28 grmol per
moles of catalyst. The obtained polyketone was
analyzed by means of a 13C NMR in
Oligomerization of ethylene was carried out
in the batch mode with a continuous feed of
ethylene into the autoclave, keeping the pres-
sure constant. To this purpose, 75-ml steel auto-
claves, equipped with glass inlets and magnetic
stirring bars were used. In a typical experiment,
0.1 mmol of the catalyst was dissolved in 10 ml
of dichloromethane, and the resulting solution
was transferred to the autoclave inlet. After-
wards, the autoclave was pressurized with 30
bars of ethylene. The autoclave was then put to
the desired temperature in a preheated oil bath.
After the reaction, the autoclave was depressur-
ized and the butenes were collected and
weighted at y788C. The nickel catalyst was
separated from the liquid phase by flash distilla-
tion of the product solution and condensation at
y788C.
Ž
.
1,1,1,3,3,3-hexafluoro isopropanol HFIPA .
13
Ž
.
C NMR 75 MHz, HFIPA, ext. C6D6 :
`
.
Ž
.
Ž
ds212.7 ppm C-O , ds35.9 ppm C C .
A sample of the polymer was analyzed by
Ž
.
means of GPC HFIPA as eluent , Mw s
1 460 000, Mn s33 582.
Non-soluble samples were analyzed by means
of a solid-state NMR that confirmed the polyke-
tone structure C NMR 75 MHz, MAS-CP :
ds210 ppm C-O , ds36 ppm C C .
13
w
Ž
Ž
.x
`
.x
.
Ž
3. Results and discussion
3.1. Synthesis of cationic nickel complexes
Ž
.
Catalyst activity TON and product distribu-
Ž
.
tion linearity, a-content, b-value were deter-
mined by using GC analysis of flash distilled
product solution with n-nonane as the internal
standard. The b-value was deduced from the
The new cationic complexes 1 and 2 have
been synthesized in good yields starting from
h -methallyl Ni Br 2, ligand and AgSbF6
3
Ä
Ž
w
.
x
Ž
.4
.
Fig. 1 .
Ž
. Ž
.
molar ratios as moles C8 r moles C6 , and
Since dppaO was not obtained in analytically
pure form, a mixture of dppaOrdppaO2 was
used for the complex synthesis.
Ž
.
as1r 1qb . Linearity was obtained from
C6-olefins.
31
1
Ä
4
P H NMR analysis proves the absence of
Ž
.
2.5. EthylenerCO copolymerization
coordinated diphosphine dioxide dppaO2 in
complex 2. The new complexes were isolated as
bright yellow powders and fully characterized
Catalytic copolymerization was carried out in
75 ml steel autoclaves equipped with a glass
by elemental analysis, 1H-, 31P H - and C H
1
13
1
Ä
4
Ä
4

(
)
50
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
Fig. 2. Synthesis of the cationic allyl palladium complexes. Ys
hexafluoroantimonate, tetrafluoroborate, triflate, tosylate; ns1
Ž
. Ž . Ž .
dppmO , ns2 dppeO , ns3 dpppO ; ns1, Ars p-tolyl
Fig. 1. Synthesis of cationic methallyl nickel complexes. Ys
hexafluoroantimonate.
Ž .
dtolpmO .
NMR spectroscopy. Furthermore, IR and SIMS
spectra have been recorded.
An important aspect concerning the catalytic
activity of these complexes is the coordination
mode of the phosphoryl group monitored with
Similar to the cationic nickel complexes with
alkylene bridged biphosphine monoxides, we
found that complexes 1 and 2 are P ^O-chelated
complexes in methylene chloride solution at
room temperature.
31
1
Ä
4
the aid of P H NMR, which is dependent on
the anion used in the reaction. As is evident
from the experimental data reported, with te-
trafluoroborate as anion, the coordination mode
is k2. When triflate is used as counteranion of
the cationic complex, it appears that the phos-
phoryl group is only partially coordinated to the
metal centre.
Bidentate coordination of the biphosphine
monoxide ligands resulted in low field coordina-
tion shifts of the phosphine and phosphoryl
31
1
Ä
4
resonances in P H NMR, and a shift to
Ž
.
lower wavenumbers for the absorption n P-O
If tosylate is the counteranion, the coordina-
tion mode is clearly k1, because of the competi-
tion between the stronger coordinating tosylate
and the phosphoryl group for the metal centre.
With dpppO as ligand, k1 coordination can be
ascribed to the lower stability of the seven
member metallacycle, which is formed when
the phosphoryl group is coordinating to the
in the IR-spectra of the complex compared to
the free ligand.
While the coordination shifts for the dpp-
benzO ligand in complex 1 are 14.9 and 29.4
ppm, the coordination shifts in the dppaO com-
plex 2 are 4.9 and 40.6 ppm, respectively.
The assignment of the chemical shifts in the
31P NMR of 2 was done according to the spec-
3
2
Ž .
Pd II centre. A similar effect has been ob-
w
Ž
. Ž
tra reported for
h -C3H5 Pd dppaO-k -
served for complexes 6, 9 and 12.
.
x
w x
P,O BF4 by Bhattacharyya et al. 32 . Notewor-
thy, complex 2 possesses fluxional behaviour of
the methallyl group at room temperature. Cool-
ing of the probe to 267 K leads to the separation
of the allylic resonances.
The methyl complexes 18–23 were synthe-
w
Ž
.
Ž
.Ž
.x
sized by the reaction of cod Pd CH3 Cl
adding 1 eq. of ligand and the appropriate silver
salt, according to the procedure shown in Fig. 3.
3.2. Synthesis of cationic palladium complexes
The complexes 10, 11, 13, 14, 16 and 17
have been synthesized in good yields, starting
from 1 eq. of bis-allyl palladium iodide, 2 eq. of
biphosphine monoxide, and 2 eq. of the relevant
Ž .
Fig. 3. Synthesis of cationic methyl palladium II complexes.
Ž .
i
Ž .
RT, dichloromethane, ii AgX, CH3CNrCH2Cl2 , 08C; Xs
hexafluoroantimonate, tetrafluoroborate; P ^ O s biphosphine
monoxide ligand.
Ž
.
silver salt Fig. 2 .

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
51
Table 5
For these complexes, as it was seen for allyl
complexes with analogous ligands, the reaction
with the silver salt has the function of exchang-
ing the strongly coordinating chloride with a
suitable weakly coordinating counteranion,
which has the effect of activating these com-
plexes towards catalysis. The ‘‘vacant coordina-
tion site’’ is stabilized via the addition of aceto-
nitrile.
Oligomerization of ethylene with cationic P ^O-chelated com-
Ž
w x
plexes 0.1 mmol Ni , 20 ml dichloromethane, 30 bar ethylene,
.
T s323 K, ts2 h
Ž
%
.
Ž .
Ž .
%
Run Complex TON
S linear S a
b
Cmax
Ž
.
Ž
.
molrmol
1
2
3
4
5
3
4
5
1
2
1692
1445
397
1641
2492
87.1
92.0
95.1
95.9
87.0
64.4
72.1
88.8
68.2
52.6
1.03 16
1.14 14
6.52 10
0.02 34
0.85 18
Surprisingly, the coordination mode of larger
bite P ^O ligands, such as dpppO, changes after
reacting the neutral methyl complex with silver
31
1
Ä
4
salt, yielding a cationic complex. P H NMR
indicates clearly that only the phosphine coor-
dinates with the palladium in the complex
Therefore, it was of special interest to inves-
tigate the new cationic nickel complexes with
biphosphine monoxides as P ^O-ligands in the
oligomerization of ethylene.
From the spectroscopic data of the com-
plexes, a strong oxygen–nickel interaction could
be deduced, and a chelate coordination of the
ligand is deduced in dichloromethane solution
in the absence of further donor ligands.
To elucidate the catalytic behavior of these
complexes in the oligomerization of ethylene,
the cationic complexes 1–5 with biphosphine
monoxide ligands have been used in ethylene
oligomerization. The results are reported in
Table 5.
The complexes 1–5 are efficient catalyst pre-
cursors for the oligomerization of ethylene to
linear, higher a-olefins. While selectivities to
linear olefins are very high, the lower selectivity
to a-olefins shows that the cationic complexes
1–5 are also efficient catalysts for the isomer-
ization of a-olefins to internal olefins. Still, the
selectivities to linear a-olefins are very impres-
sive, and to the best of our knowledge, the
results obtained with complexes 1–5 in terms of
selectivity are the best reported for cationic
w
Ž
.
bis- 1,3-bis diphenylphosphino propane - mono-
2
Ž
Ž
.Ž
.x
.
Ž .x
xide-k -P,O chloro methyl palladium II
w
Ž
.Ž
.
CH3 Cl Pd dpppO 2. This observation can
be explained by considering a dimeric structure
for the chloro complex Fig. 4 . The reaction of
the chloro complex with 1 eq. of silver salt and
acetonitrile yields a complex that shows the
coordination of P-O functionality.
The complexes 1–23 see Table 1 for the
numbering have been used as catalyst precur-
sors for carbon–carbon linkage reactions. We
now want to present and discuss the results of
our catalysis runs.
Ž
.
Ž
.
3.3. Ethylene oligomerization: nickel complexes
Cationic organyl nickel complexes with P ^O
ligands, e.g., diphenylphosphinoalkylcarboxyl-
ates, are active as catalysts in the oligomeriza-
tion of olefins. For ethylene, this type of com-
plex shows only low selectivity to higher linear
olefins. This has been ascribed to hemilability
w
x
of the ligand under catalysis conditions 38 .
Fig. 5. Proposed coordination mode of ethylene to nickel in
wŽ .x
Fig. 4. Alleged structure for the complex CH3 Cl Pd dpppO .
2
.Ž
.
Ž
complex 3.

(
)
52
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
Table 6
Table 8
Catalytic results with in situ-formed nickel complexes obtained by
Addition of monodentate phosphines to a solution of complex 1
3
Ž
.
Ž
.
the reaction of h -methallyl Ni cod SbF6 and 1 eq. of ligand
Ž
.
Ž
%
.
Ž .
b
Ž .
%
Run n Ligand : TON
S linear S a
. Ž
Cmax
Ž
.
Ž
%
.
Ž
%
.
Ž
.
Ž
.
Run n ligand :
TON
S linear S a
. Ž
b
Cmax
n Ni
molrmol
Ž
.
.
Ž
.
Ž
.
Ž
.
n complex
molrmol
molrmol
Ž
molrmol
1
2
3
4
5
6
7
0
1641
861
95.9
99.0
98.4
97.0
98.2
93.6
95.4
68.2 0.02 34, waxes
90.6 0.05 waxes
96.4 1.74 14
94.5 6.60 10
95.8 6.87 8
1
2
3
4
5
6
0
610
65.3
89.7
94.5
63.0
96.5
89.2
7.0 6.00
8
0.50 PPh3
1.06 PPh3 1475
2.07 PPh3
4.09 PPh3
1.09 PCy3 645
2.09 PCy3 138
1.03 dppmO
1.03 dppeO
1.09 dpppO
1.06 dppbenzO 2295
1.12 dppaO 1478
1724
1470
1910
71.6 1.08 16
83.9 1.18 14
16.3 3.20 10
67.6 0.12 34
79.6 0.95 16
886
264
82.7 0.04 waxes
87.1
14
P ^O-chelated nickel complexes so far. The
comparison with selectivities reported by Ecke
and Schulz for phosphinocarboxylates as neutral
P ^O-ligands shows that linearities, as well as
a-contents of the C6-olefins, are dramatically
increased through the use of biphosphine
length of product olefins as a parameter for
oligomerization grade, increases with decreas-
ing chelate ring size of the complex. While the
dppmO complex is yielding oligomers up to
C16, the dpppO complex yields only short-
chained olefins. Assuming that only the square-
planar nickel hydride is active in the oligomer-
ization, the chain length of the built product will
depend on the chelate ring size, because larger
chelate rings will favour tetrahedral configura-
tion.
The closer the coordination geometry to the
square-planar coordination, the higher the
oligomerization number. Furthermore, the higher
the rigidity of the ligand backbone, the higher
the activation energy for a b-elimination via a
penta-coordinated species and the higher the
oligomerization number. This was proven by
synthesising and applying a cationic complex
with dppbenzO as P ^O ligand. The slightly
lowered activity of the dppbenzO complex in
comparison with the dppmO complex can be
explained invoking a diffusion-controlled reac-
tion due to the resulting slurry of waxes that
limits further conversion of ethylene to
w
x
monoxides as P ^O-ligands 18,19 . We ascribe
the good selectivities to very stable
a
`
nickel oxygen bond and, therefore, a chelate
coordination of the P ^O-ligand, similar to
chelate coordination of anionic ligands in
SHOP-type catalysts.
The catalysis results can best be rationalised
by the assumption that the chelate coordination
remains intact throughout the course of cataly-
sis. Thus, ethylene is not replacing the phospho-
ryl group but is coordinating and inserting into
the organyl group without the cleavage of the
`
Ž
.
nickel oxygen bond Fig. 5 .
The support for the proposal in Fig. 5 stems
from the following considerations.
Activities of the complexes 1–5 follow the
same trend as for neutral complexes with an-
ionic chelate P ^O-ligands. The activity of com-
plexes 1–5, as well as the maximum chain
Table 7
Distribution of C6-isomers for reactions reported in Table 5
Run 3-Methyl-1-pentene 1-Hexene 2-Ethyl-1-butene Cis and trans 3-hexene 3-Methyl-2-pentene Cis and trans 2-hexene
1
2
3
4
5
1.5
1.5
1.4
1.4
3.2
64.3
71.6
70.1
67.6
7.0
10.6
8.2
0
0
0.9
5.4
4.0
3.2
3.3
19.1
0.9
0.6
0
2.1
30.5
17.5
14.1
25.4
25.7
39.3

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
53
Table 9
The dppaO complex shows remarkably high
activity compared to the alkylene and phenylene
bridged ligands. Compared to neutral com-
plexes, cationic complexes seem to inherit a
high activity but a lower oligomerization num-
ber. Table 7 describes the selectivity for the
C6-isomers.
Comparison with hemilabile P ^O ligands by in situ catalysis with
3
4
ÄŽ
.Ž
.
Ž .4
h -methallyl h -1,5-cyclooctadiene nickel II hexafluoroanti-
monate
Ž
.
Ž
%
.
Ž .
b
Ž .
%
Run n Ligand :
TON
S linear S a
. Ž
Cmax
Ž
.
Ž
.
n Ni
Ž
molrmol
.
molrmol
1
2
3
4
5
6
7
1.05 dppanis
1.04 dppres
1.06 dppOPh
1.11 dppacet
1.09 dppbald
1.08 dpppaEt
1252
1076
1712
661
1952
552
26.8
32.8
25.9
39.4
45.7
38.4
43.7
1.1 12.98
1.6 21.22
8
8
8
Addition of different amounts of monoden-
tate phosphine to a solution of dppbenzO com-
0.8
2.4
7.6
4.0
5.2
9.87
4.38 10
9.87 10
Ž
.
plex 1 Table 8 had the expected effect of
lowering the oligomerization grade and the cata-
lyst activity. Remarkably, we still observed cat-
alytic activity after addition of 2 eq. PCy3 to
9.36
8
1.04 dppbenzaMe 3192
5.38 10
w
x
complex 1. Despeyroux 39 and Muller et al.
¨
w
x
oligomers. At this time, it still remains unclear
whether the good selectivities are only a result
of high electron density at the nickel centre
through effective bonding of the donor group or
whether the selectivity is a result of effective
shielding of the nickel through the phenyl-sub-
stituted phosphoryl group as well.
40 reported the isolation of catalytically inac-
tive, neutral nickel hydrides after the addition of
2 eq. of PCy3 to an active oligomerization
system. It seems likely that reaction pathways
are different for cationic and neutral complexes.
Probably, for oligomerization with cationic
complexes, a higher coordinated species, still
possessing catalytic activity, can be built. The
outstanding performance of biphosphine monox-
ide ligands is shown in comparison to both,
defined complexes and in situ catalysts with
The results with defined complexes could be
supported through applying in situ catalysts
3
Ä
w
.
x
Ž
.4
starting from h -methallyl Ni cod SbF6 and
a stoichiometric amount of ligand. After the
preformation of the catalyst and the substitution
of 1,5-cyclooctadiene through the P ^O ligand,
1,5-cyclooctadiene has no effect on the catalyst
performance in comparison to the defined com-
plexes 1–4, as can be deduced from the results
in Table 6.
Ž
.
other P ^O-ligands Table 9 .
While nickel complexes with biphosphine
monoxides show excellent selectivities to higher
a-olefins, application of other neutral P ^O-
ligands led only to catalyst systems with poor
selectivities. Among the used ligands are also
the diphenylphosphinoalkylcarboxylates re-
ported by Ecke and Schulz. While the selectivi-
ties to linear olefins are in the range of 25–50%,
the a-olefins contents are drastically reduced.
The difference in catalytic activity and selec-
tivity from dpppO complex 5 and the analogous
3
Ä
w
x
Ž
.4
in situ system h -methallyl Ni cod SbF6rdp-
Ž
.
ppO entry 4 cannot be easily explained.
Table 10
Olefin oligomerization with cationic allyl and methyl palladium complexes under used conditions: 30 bar const., 20 ml CH2Cl2 , 2 h, 708C
Run Ligand
AllrMe, Cat.
TOF
S
S
Cmax C4
C6
C8
C10
C12
b
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
anion mmol 1rh
linear
1-hexene
mass%
mass%
mass%
mass%
mass%
1
2
3
4
5
6
dppmO
All, SbF6 0.040 7794 75.8
44.6
45.6
14.7
30.2
15.1
0.6
12
12
10
12
10
10
65.9
77.6
83.7
65.3
85.7
80.6
24.7
17.0
13.7
24.6
11.8
16.8
7.1
4.3
2.3
7.7
32.2
2.3
1.8
0.9
0.3
1.9
0.3
0.3
0.5
0.2
–
0.5
–
3.64
4.30
6.99
3.25
6.23
8.92
dtolpmO All, SbF6 0.046 4228 81.2
dppeO
dppmO
dtolpmO Me, SbF6 0.050 5012 77.7
dppeO Me, SbF6 0.050 5512 49.3
All, SbF6 0.046 4747 52.5
Me, SbF6 0.050 8974 73.5
–

(
)
54
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
Table 11
EthylenerCO copolymerization catalysed by allyl palladium complexes
Ž
.
Conditions: ethylene 30 bars, CO 30 bars, solvent dichloromethane 10 ml , reaction temperature 508C.
mol 10y4
Conversion CO%
TON
Ž .
m ethylene g
Ž .
m CO g
Ž .
m polymer g
Run
Complex
Ž
9
. Ž
.
Ž
.
1
2
3
4
5
6
7
8
9
12 all Pd dppmO Tos
Ž . Ž
1
4.60
4.60
3.91
4.80
4.71
4.58
3.71
4.25
3.10
2.59
2.72
2.96
2.40
2.66
2.48
2.65
2.58
2.65
9.3
39.5
45.0
5.8
14.3
15.7
1.0
171
760
1000
101
274
281
21
0.48
2.15
2.66
0.28
0.76
0.78
0.06
0.23
0.75
.
Ž
.
all Pd dppmO Tf
all Pd dppmO BF4
. Ž
1.01
0.95
0.99
0.99
0.99
1.00
1.00
1.00
Ž . Ž
.
Ž
.
6
Ž
Ž
.
.
Ž
Ž
.
.
13 all Pd dppeO Tos
. Ž
10 all Pd dppeO Tf
Ž . Ž
.
Ž
.
7
all Pd dppeO BF4
. Ž
. Ž
Ž
.
.
Ž
Ž
.
.
14 all Pd dpppO Tos
Ž
11 all Pd dpppO Tf
4.4
14.1
82
268
Ž . Ž
8
.
Ž
.
all Pd dpppO BF4
Both the oligomerization grades and the re-
sulting Cmax are similar to those obtained with
monodentate phosphines, e.g., PPh3. Therefore,
we conclude that these P ^O-ligands behave as
hemilabile ligands under catalysis conditions, in
contrast to the biphosphine monoxides.
creased selectivity to linear products although
turnover frequencies are much lower.
Moreover, the cationic methyl complexes are
more active than their allyl analogues. The
turnover frequencies are about 15% lower when
using the allyl precursor. This can be ascribed
to the activation energy of the starting step to
form the catalytic active species. The selectivity
to linear ethylene oligomers are in the same
range, but still a little bit higher when using
allyl precursor complexes.
To further investigate the chelate control, we
3
Ä
Ž
.
tried to synthesize the complex h -methallyl
Ž
.Ž
Ž ..4
Ni Ph3P Ph2 MeP O SbF6. Attempts to fully
characterize the complex failed due to its low
stability. Nevertheless, we applied the in situ
complex to catalysis without further purifi-
cation.
In addition, the isomerization activity of
Ž
methyl complexes due to selectivity to 1-
.
hexene is much higher than that of the corre-
3.4. Oligomerization of ethylene catalysed by
spondent allyl complexes. This can only be
explained with the presence of 1 eq. acetonitrile
from the starting compound in the case of methyl
complexes. Another explanation for the lower
amount of 1-hexene might be the incorporation
( )
Pd II complexes
The influence of chelating ligands on ethy-
lene oligomerization applying Pd-complexes is
shown in Table 10. With dppmO, the best activ-
ities are achieved while once more, the effect of
ring size of the chelating complex to catalysis is
obvious from the results obtained. Five ring
Ž
.
chelates dppmO, dtolpmO show higher selec-
tivities to linear, as well as to alpha olefins than
Ž
.
six-membered rings do dppeO . b-values of
Schulz–Flory distribution are rising in the row:
dppmO-dtolpmO-dppeO, but major prod-
Ž
.
ucts obtained are butenes 65–85% , while the
amount of decenes or dodecenes is negligible.
The difference in electronic and steric effects of
dtolpmO in comparison to dppmO leads to in-
Fig. 6. Activity of complex 6 as a function of reaction time in the
ethylenerCO copolymerization.

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
55
Table 12
EthylenerCO copolymerization
Conditions: ethylene 30 bars, CO 30 bars, solvent dichloromethane 10 ml , reaction time 15 h.
Ž
.
Ž .
Ethylene g
Ž .
m CO g
Ž .
m polymer g
Entry
Complex
mmol
Conversion CO%
TON
Ž
.
.
.
Ž
Ž
Ž
.
.
.
1
2
3
4
5
6
6 all Pd dppmO BF4
0.099
0.049
0.025
0.098
0.049
0.025
5.04
4.88
4.93
5.31
5.62
5.50
2.77
3.14
2.93
2.77
2.92
2.98
92
86
53
96
84
54
1825
3915
4455
1950
3320
4519
5.11
5.40
3.13
5.34
4.60
3.21
Ž
6 all Pd dppmO BF4
Ž
6 all Pd dppmO BF4
.Ž
Ž
Ž
.
.
Ž
Ž
Ž
.
.
.
18 CH3 CH3CN Pd dppmO BF4
.Ž
18 CH3 CH3CN Pd dppmO BF4
.Ž
Ž
.
18 CH3 CH3CN Pd dppmO BF4
of already produced a-olefins as substrate in the
catalytic cycle.
in the order: tosylate, triflate, tetrafluoroborate;
this explains the higher activity of the com-
plexes bearing BF4y as anion. The effect of
temperature was analyzed by setting analogous
experiments at different temperature. The high-
est activity was reached at 808C; decomposition
of the catalyst is invoked for the drop in activity
above 808C.
Another effect of the strong donor aceto-
nitrile is its competition with ethylene or prod-
uct olefins for coordination on palladium, and
the consequent higher chain transfer rates ob-
served in catalysis with methyl complexes. The
same effect is observed in our presented nickel
catalysed ethylene oligomerization when phos-
Based on the conclusions drawn from this
first screening, we decided to continue our in-
vestigations with the most active complex,
w
x
phines are added to the solution 41 .
Ä
Ž
.
Ž
.
4
Ž .
namely all Pd dppmO BF4 6 at the highest
temperature possible, i.e., 808C.
3.5. Alternating copolymerization of ethylene
( )
and carbon monoxide with palladium II com-
In order to assess if an induction period was
necessary to start the catalytic cycle, five differ-
ent experiments were set under the same condi-
tions just varying the reaction time. The results
are shown in Fig. 6, and prove that no induction
period is required to trigger the catalytic cicle.
The observed change in slope in the curve may
be due to the polymerization reaction turning
under diffusion control above 3 h.
The amount of the catalyst employed was
also subject to optimisation. We observed a
drop in catalytic activity for 6 above 0.05 mmol.
This is obviously due to the decomposition of
plexes
In order to perform a first screening of
catalytic activity, the complexes 6–14 were
employed in the catalytic copolymerization of
ethylene and CO at 508C. The results are sum-
marized in Table 11.
Two features appear from these results: the
dppmO complexes combined with BF4y are the
most active ones. An explanation of this be-
haviour can be given if it is assumed that
dppmO, dppeO and dpppO form five-, six- and
Ž .
seven-membered metallacycles with Pd II . The
higher stability of the five terms metallacycle
that is formed in the dppmO complexes can be
invoked to justify that the catalyst is more stable
and, therefore, more active, whereas dppeO and
Ž .
dpppO complexes tend to be reduced to Pd 0
under reaction conditions.
The effect of the counteranion is dependent
upon its coordination ability. It should increase
Ž
.
Fig. 7. In situ formation of the chelate complex dppmO -
.Ž
Ž
.
Pd CH3 NCCH3 BF4.

(
)
56
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
Table 13
EthylenerCO copolymerization
Conditions: ethylene 30 bars, CO 30 bars, solvent dichloromethane 10 ml ; reaction temperature 808C; reaction time 15 h. For reactions 4,
.Ž
Ž
.
.
Ž
.
Ž
.
Ž
5, and 6, the precursor complex is cod Pd NCCH3 CH3 BF4 0.1 mmol .
Ž .
m ethylene g
Ž .
m CO g
Ž .
m polymer g
Entry
Complex or ligand
mmol
Conversion CO%
TON
Ž
.Ž
.
.
.
Ž
Ž
Ž
.
.
.
1
2
3
4
5
6
18 CH3 CH3CN Pd dppmO BF4
.Ž
0.099
0.1
0.099
0.098
0.098
0.099
5.04
4.96
4.68
4.90
5.30
5.21
2.77
2.77
2.69
2.60
2.83
2.73
92
29
30
95
28
18
1825
575
566
1793
598
473
5.11
1.61
1.58
4.92
1.65
1.32
Ž
19 CH3 CH3CN Pd dppeO BF4
Ž
.Ž
20 CH3 CH3CN Pd dpppO BF4
dppmO
dppeO
dpppO
Ž .
Ž .
the catalyst via reduction of the Pd II to Pd 0
in the reaction medium.
preformed complexes previously described, but
also through the in situ formed catalysts, by the
use of particular precursor complexes like the
A further reaction screening was done to
establish the activity of the methyl complexes
18, 19 and 20. The question arising was whether
an allyl-Pd-group or a methyl-Pd-group gives
different results. Data for this screening are
collected in Table 12.
w
Ž
.
Ž
.Ž
.x
methyl complex cod Pd NCCH3 CH3 BF4.
When this complex is reacted with an eq. of
bidentate ligand, the coordinated diolefin cy-
clooctadiene is scavenged from the complex
itself, giving rise to the catalyst precursor, which
is responsible for the copolymerization reaction
We found that it is possible to activate the
copolymerization reaction, not only through the
Ž
.
Fig. 7 .
Fig. 8. Alleged chain growth pathways for CO migratory insertion in the ethylenerCO copolymerization with palladium P ^PO complexes
Ž
.
Pol: growing polyketone; Y: counteranion; L: solvent .

(
)
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
57
w
x
It is evident from Tables 12 and 13 that
effect was observed by Vrieze et al. 45 in the
course of the study of the carbonylation reaction
Ž
chelate ring size influences catalytic activity in
.
Ž .
Ž .
the order dppmO)dppeO)dpppO and that
of norbornene with Pt II or Pd II complexes
with phosphino-amines as ligands. It is safe to
assume that similar effects might play a role in
the ethylene insertion in the Pd–acyl bond.
methyl complexes do not exhibit a higher cat-
alytic activity than their allyl analogues. This
can be rationalised in terms of the activation
step, which is faster than the chain growth in
the ethylenerCO copolymerization.
4. Conclusions
The self-explanatory mechanism of the acti-
vation of ethylenerCO copolymerization catal-
Ž .
Ž .
New nickel II and palladium II complexes
with biphosphine monoxide ligands have been
synthesized and characterized. Cationic organyl
nickel complexes with biphosphine monoxides
are very efficient catalysts in the oligomeriza-
tion of ethylene towards higher a-olefins.
Cationic palladium II complexes exhibit activ-
ity towards the oligomerization of ethylene and
the copolymerization of ethylene and CO.
Ž .
ysed by hemilabile complexes of Pd II was
thoroughly investigated by Mecking and Keim
w
x
42 and is shown in Fig. 8.
In comparison to Shell’s results 43 , the
w
x
activity of our complexes is lower. A possible
explanation could lie in the ‘‘soft–hard’’ nature
of the ligand. Let us, for example, consider the
CO insertion in the growing chain. It is widely
accepted that CO migratory insertion into a
Pd–alkyl bond is favoured if the alkyl group
bears a partial negative charge and the coordi-
nated CO, on the other hand, bears a partial
Ž .
Acknowledgements
Ž
positive charge for a complete review, see Ref.
Financial support from the Ministerium fur
Wissenschaft und Forschung des Landes Nor-
¨
w
x.
44 . This is the case if a phosphorous atom is
trans to the alkyl growing chain, and a P-O
group is trans to the coordinated CO. Species 1
in Fig. 8, which represents the starting species
for pathway 1 or 2, shows the growing chain cis
to phosphorous and CO trans to it, a situation
unfavourable for insertion because the alkyl
growing chain is cis to the phosphorous atom
and trans to the oxygen atom. The starting
species 1 has to isomerize to 2 before migratory
insertion to yield 4 can happen. This isomeriza-
tion is an energetically unfavourable process
and would lead to slower insertion rates with
Ž
.
drhein-Westfalen Katalyseverbund NRW and
from the Deutsche Forschungsgemeinschaft is
gratefully acknowledged. Cosimo Francesco
Nobile, Gian Paolo Suranna and Piero Mastror-
illi gratefully acknowledge Italian MURST and
CNR for financial support.
References
w x
Ž .
G. Wilke, Angew. Chem. 100 1988 189.
W. Keim, Angew. Chem., Int. Ed. Eng. 29 1990 235.
W. Keim, F.H. Kowaldt, R. Goddard, C. Kruger, Angew.
¨
Chem. 90 1978 493.
1
w x
2
Ž .
w x
3
Ž .
respect to the P ^P or N ^N Pd II complexes,
Ž
.
where isomerization is not needed. Path 2 shows
the kinetically unfavoured direct migration that
leads to the thermodynamically stable acyl
product 3, which quickly rearranges into 4.
Therefore, the rearrangement barrier that the
complex has to undergo in path 1, or the kinetic
barrier in the migratory step in path 2, can
account for the slower growing rate of the
copolymer in the CO insertion step. A similar
w x
Ž .
4
w x
5
A. Bader, E. Lindner, Coord. Chem. Rev. 108 1991 27.
Ž
.
W. Kaminsky, M. Arndt, in: B. Cornils, W. Herrmann Eds. ,
Applied Homogeneous Catalysis, VCH, Weinheim, 1996.
G. Britovsek, V.C. Gibson, D.F. Wass, Angew. Chem. 111
w x
6
Ž
.
1999 448.
w x
7
G.W. Parshall, S.D. Ittel, Homogeneous Catalysis: The Ap-
plications and Chemistry of Catalysis by Soluble Transition
Metal Complexes, 2nd edn., Wiley-Interscience, New York,
1992.
w x
8
C.M. Killian, L.K. Johnson, M. Brookhart, Organometallics
Ž
.
1997 2005.

(
)
58
w x
I. Brassat et al.rJournal of Molecular Catalysis A: Chemical 157 2000 41–58
w
w
w
w
w
x
9
L.K. Johnson, C.M. Killian, M. Brookhart, J. Am. Chem.
29 G.J.P. Britovsek, K.J. Cavell, M.J. Green, F. Gerhards, B.W.
Skelton, A.H. White, J. Organomet. Chem. 533 1997 201.
30 I. Brassat, U. Englert, W. Keim, D.P. Keitel, S. Killat, G.P.
Suranna, R. Wang, Inorg. Chim. Acta 280 1998 150.
31 N.A. Bondarenko, M.V. Rudomino, E.N. Tsvetkov, Synthe-
Ž
.
Ž
.
Soc. 117 1995 6414.
w
w
w
x
Ž
.
x
10 J. Skupinska, Chem. Rev. 91 1991 613–648.
x
Ž
.
Ž
.
11 W. Keim, Angew. Chem. 102 1990 251.
x
x
12 C.M. Killian, L.K. Johnson, M. Brookhart, Organometallics
Ž
.
Ž
.
Ž
.
16 1997 2005, and references therein .
sis 1991 125.
w
x
Ž
.
Ž
x
13 B.L. Small, M. Brookhart, JACS 129 1998 7143, and
32 P. Bhattacharyya, A.M.Z. Slawin, M.B. Smith, J.D. Woollins,
.
Ž
.
references therein .
Inorg. Chem. 35 1996 3675.
w
x
x
14 W. Keim, B. Hoffmann, R. Lodewick, M. Peuckert, G.
33 G.P.C.M. Dekker, A. Buijs, C. Elsevier, K. Vrieze, P.W.N.M.
Ž
.
Schmitt, J. Fleischhauer, U. Meier, J. Mol. Catal. 6 1979
Van Leeuwen, W.J.J. Smeets, A.L. Spek, V.F. Wang, C.H.
Ž
.
79.
Stam, Organometallics 11 1992 1937.
w
w
w
x
Ž
.
w
w
x
15 D. Vogt, in: B. Cornils, W. Herrmann Eds. , Applied Homo-
geneous Catalysis, VCH, Weinheim, 1996.
16 M.C. Bonnet, F. Dahan, A. Ecke, W. Keim, R.P. Schulz, I.
34 G. Wilke, DOS 1,194,417-10.06.1965.
35 R.B.A. Bardy, I. Tkatchenko, J. Chem. Soc., Chem. Com-
x
x
Ž
.
mun. 1981 49.
Ž
.
w
x
Ž
.
Tkatchenko, J. Chem. Soc., Chem. Commun. 1994 615.
36 D.L. Tibbetts, T.L. Brown, J. Am. Chem. Soc. 91 1969
x
17 D. Matt, M. Huhn, J. Fischer, A. De Cian, W. Klaui, I.
¨
1108.
w
x
Tkatchenko, M.C. Bonnet, J. Chem. Soc., Dalton Trans.
37 R.E. Rulke, J.M. Ernsting, A.L. Spek, C.J. Elsevier,
¨
Ž
.
Ž
.
1993 1173.
P.W.N.M. van Leeuwen, K. Vrieze, Inorg. Chem. 32 1993
w
w
w
w
w
w
w
w
x
18 A. Ecke, Dissertation, RWTH Aachen, 1995
5769.
x
w
x
19 R.P. Schulz, Dissertation, RWTH Aachen, 1993.
38 M.C. Bonnet, F. Dahan, A. Ecke, W. Keim, R.P. Schulz, I.
Tkatchenko, J. Chem. Soc., Chem. Commun. 1994 615.
39 B. Despeyroux, PhD Thesis, Aachen, 1981.
x
Ž
.
Ž
.
20 Chem. Week 1 1995 22.
x
Ž
.
w
w
x
x
21 F.Y. Xu, J.C.W. Chien, Macromolecules 26 1993 3485.
x
Ž
.
22 A. Sen, Adv. Polym. Sci. 73r74 1986 126.
40 U. Muller, W. Keim, C. Kruger, P. Betz, Angew. Chem. 101
¨
¨
x
Ž
.
.
Ž
.
23 P. Margl, T. Ziegler, J. Am. Chem. Soc. 118 1996 7337.
1989 1066.
x
Ž
w
w
w
x
24 P. Margl, T. Ziegler, Oganometallics 15 1996 5519.
41 I. Brassat, Dissertation, RWTH Aachen, 1998.
42 S. Mecking, W. Keim, Organometallics 15 1996 2650.
43 E. Drent, J.A.M. vanBroekhoven, P.H.M. Budzelaar, Recl.
Trav. Chim. Pays-Bas 115 1996 263, and refs. therein.
44 K. Cavell, Coord. Chem. Rev. 155 1996 209.
45 K. Vrieze, P.V. Leeuwen et al., Organometallics 11 1992
1937.
x
Ž
.
x
Ž
.
25 W. Keim, H. Maas, S. Mecking, Z. Naturforsch. 50b 1995
x
430.
w
w
x
x
Ž
.
Ž
.
26 S. Mecking, W. Keim, Organometallics 15 1996 2650.
27 G.J.P. Britovsek, W. Keim, S. Mecking, D. Sainz, T. Wag-
w
w
x
x
Ž
.
Ž
.
Ž
.
ner, J. Chem. Soc., Chem. Commun. 1993 1632.
w
x
Ž
.
28 W. Keim, R.P. Schulz, J. Mol. Catal. 92 1994 21.