Square-planar mesitylenido(triphenylphosphane)nickel(II) complexes containing bidendate N,O-ligands: Changes in catalytic efficiency upon small alterations in the ligand backbone

Article abstract of DOI:10.1016/j.jorganchem.2012.08.030

Square planar arenido(triphenylphosphane)nickel(II) complexes containing a heterocyclic bidentate N,O-chelate ligand are catalysts for the copolymerisation of ethene and carbon monoxide. To examine the influence of the N,O-ligand on the catalytic activity new nickel(II) complexes with altered heterocyclic ring size in the corresponding N,O-ligands were synthesised and fully characterised. The crystal structures of all protonated N,O-ligands and the corresponding nickel complexes were determined. The catalytic activity of the new complexes in the copolymerisation reaction of ethene and carbon monoxide as well as in the polymerisation reaction of ethene were studied.

Full text of DOI:10.1016/j.jorganchem.2012.08.030

Journal of Organometallic Chemistry 720 (2012) 73e80
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Square-planar mesitylenido(triphenylphosphane)nickel(II) complexes containing
bidendate N,O-ligands: Changes in catalytic efficiency upon small alterations in
the ligand backbone
, ,
,
Udo Beckmann a 1, Monika M. Lindner a 1, Eva Eichberger a, Walter Frank b
*
a Institut für Anorganische Chemie und Strukturchemie, Lehrstuhl I: Bioanorganische Chemie und Katalyse, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225
Düsseldorf, Germany
b Institut für Anorganische Chemie und Strukturchemie, Lehrstuhl II: Material- und Strukturforschung, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1,
40225 Düsseldorf, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Square planar arenido(triphenylphosphane)nickel(II) complexes containing a heterocyclic bidentate N,O-
chelate ligand are catalysts for the copolymerisation of ethene and carbon monoxide. To examine the
influence of the N,O-ligand on the catalytic activity new nickel(II) complexes with altered heterocyclic
ring size in the corresponding N,O-ligands were synthesised and fully characterised. The crystal struc-
tures of all protonated N,O-ligands and the corresponding nickel complexes were determined. The
catalytic activity of the new complexes in the copolymerisation reaction of ethene and carbon monoxide
as well as in the polymerisation reaction of ethene were studied.
Received 21 June 2012
Received in revised form
14 August 2012
Accepted 27 August 2012
Keywords:
Nickel complexes
N,O-Ligands
Catalysis
Ó 2012 Elsevier B.V. All rights reserved.
Polyketone
1. Introduction
were interested in tuning the catalytic activity of the complex by
slightly altering the framework of the N,O-ligand. Kläui et al.
Aliphatic polyketones produced by the catalysed copoly-
merisation of olefins and carbon monoxide are an interesting class
of relatively new polymers. These thermoplastic copolymers
exhibit outstanding characteristics such as chemical resistance and
remarkable thermal properties [1e3]. Polyketones are featured by
an exceptional environmental compatibility due to photo-
degradability through Norrish type I and II mechanisms [4e7],
making them interesting materials in green chemistry. Industrially
aliphatic polyketones are produced by the palladium catalysed
copolymerisation of carbon monoxide and ethene yielding a strictly
alternating aliphatic polyketone [8e11]. However, the costly noble
metal palladium is not recovered and remains in the polymer. In the
search for alternatives, nickel complexes turned out to be prom-
showed that a prolonged perfluorinated alkyl chain (see Fig. 1)
results in higher catalytic efficiencies whereas methyl or phenyl
groups at the same position result in less efficient complexes and
a methoxy group drops the efficiency to about zero [12]. In this
work we report on altering the ring size of the heterocyclic ligand
from five to six and seven membered rings, the synthesis and
characterisation of the resulting nickel complexes and the studies
of the new compounds as catalysts for the copolymerisation of
ethene and CO.
2. Results and discussion
Complexes of the type shown in Fig.1 can be prepared according
to Scheme 1.
ising candidates. The most efficient nickel complex to date for the
0
copolymerisation of ethene and CO, K1 , is shown in Fig. 1 [12].
It is already structurally characterised and contains a bidentate
N,O-chelating ligand which coordinates to the nickel centre in
a square planar manner forming a six-membered chelate ring. We
The reaction of the square-planar nickel complex (SP-4-3)-
[NiBr(mes)(PPh3)2] (R
¼
CH3) or (SP-4-3)-[NiBr(2-tol)(PPh3)2]
(R ¼ H) with an appropriate deproto0nated N,O-ligand (L1e3 ꢀ
) yields
0
the target complexes K1e3 and K1 e3 . We reported the syntheses of
the ligands HL1e3 in a recent paper [13].
Complex K1 was synthesised as previously described [14]. The
synthesis of K2 and K3 involves the deprotonation of the protonated
N,O-ligand HL2 or HL3 and the following reaction of the
* Corresponding author. Fax: þ49 211 81 12287.
E-mail address: Udo.Beckmann@uni-duesseldorf.de (U. Beckmann).
U. Beckmann and M. M. Lindner contributed equally to this work.
1
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.08.030

74
U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
0
Fig. 1. The most efficient nickel complex K1 for the copolymerisation of ethene and CO
to date.
Fig. 2. Complexes with a xylenido ligand.
deprotonated ligand (L2)ꢀ or (L3)ꢀ, respectively, with (SP-4-3)-
[NiBr(mes)(PPh3)2] in a toluene solution. We investigated the
suitability of several bases for the ligand deprotonation. No reaction
takes place using e.g. triethylamine or “proton sponge” (1,8-
bis(dimethylamino)naphthalene). Interestingly, triethylamine is
a suitable base for the deprotonation of HL1, whereas with HL2 or
HL3 no reaction occurs under equal conditions. We also tried to
react the ligands HL1e3 with (SP-4-3)-[NiBr(mes)(PPh3)2] in the
presence of silver(I) oxide which acts as base and bromide scav-
enger in heterogeneous phase. This again was only successful in the
case of HL1, whereas HL2 and HL3 showed no reaction. Best results
were achieved by first using sodium bis(trimethylsilyl)amide to
generate the sodium salt of any of the three ligands in toluene
solution and successively adding the sodium salt to a toluene
solution of (SP-4-3)-[NiBr(mes)(PPh3)2].
To distinguish the steric and inductive effects of the methyl
groups at the arenido ligand we also00synthesised the 2,4-xylenido
000
and the 2,6-xylenido complexes K1 and K1 (s. Fig. 2) in the
same way as depicted in Scheme 1 except that (SP-4-3)-[NiBr(2,4-
xyl)(PPh3)2] and (SP-4-3)-[NiBr(2,6-xyl)(PPh3)2] were used.
If the stabilising effect is mainly due to the sterical situation in
0
the 2,6-posi0t0ion, the 2-toluenido complex K1 and the 2,4-xylenido
complex K1 should have similar reactivities as well as the reac-
tivities of the mesitylenido complex K1 and the 2,6-xylenido
000
complex K1 should resemble. The stability and reactivity of the
complexes were investigated using the previously described reac-
tion with 2-hexyne [15]. 2-Hexyne inserts into the nickelecarbon
bond and the resulting insertion product reacts under 0-00hydride
b
0
00
elimination [15]. The four complexes K1, K1 , K1 and K1 can be
ranked qualitatively in the following order of decreasing reactivity:
0
00
000
Complex K1 is very similar0 to the already known and structur-
K1 > K1 > K1 > K1, obviously due to the inductive effects of the
ally characterised complex K1 shown in Fig. 1 [12]. K1 comprises
methyl groups, not merely steric effects.
0
0
0
a mesitylenido ligand instead of a 2-toluenido ligand in K1 . We
In solid state all complexes K1e3 and K1 e3 appear to be air-
stable, they form yellow to orangeered coloured crystals and
introduced the mesitylenido group mostly for stability reasons as
the mesitylenido nickel(II) complexes turned out to be significantly
more stable in benzene or dichloromethane solution in air than
their 2-toluenido analogues. No decomposition that would be
noticeable in the 31P{1H} NMR spectrum takes place in a benzene
solution for weeks even under aerobic conditions, whereas the
corresponding 2-toluenido nickel(II) complexes decompose to
paramagnetic nickel(II) compounds, triphenylphosphane and tri-
phenylphosphane oxide within days [15]. Decomposition is even
faster in analogous complexes comprising a benzenido ligand.
Closer examination showed that these complexes are only stable
for a few hours in solution under inert conditions. The stability of
the complex is obviously dependent on the number of methyl
groups at the arenido ligand.
were fully characterised.
0
The complexes K1 and K1 are active catalysts in the homoge-
neous copolymerisation of carbon monoxide and ethene. We
determined the overall efficiency (g polyketone per g Ni) of the
catalyst complexes K1e3 in toluene solution (ca. 2e3 mM) at 60 ꢁC
and 50 bar (CO partial pressure: 10 bar, C2H4 partial pressure:
40 bar) in a standard 100 mL stainless steel autoclave setup
comprising a glass inlet over 24 h. We found the efficiency of K1
varying between 8000 and 10,000, comparable to the previously
0
reported efficiency for K1 of about 11,000 [12], leading to polymers
with molecular weights of >105 [16]. Interesting results were ob-
0
0
tained using K2 and K3 as well as K2 and K3 , respectively, in the
same setup instead of K1. No formation of polyketone was observed.
0
0
Scheme 1. Synthesis of the complexes K1e3 and K1 e3
.

U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
75
The overall efficiency under the said conditions for K2 and K3 is
zero. Even at higher temperatures up to 100 ꢁC and up to 100 bar as
well as varying the CO/ethene ratio no copolymerisation reaction
0
0
takes place using K2, K2 , K3 or K3 as catalysts.
In search for explanations for this unexpected behaviour in the
copolymerisation of carbon mon0oxide and ethene, we investigated
0
the reaction of the complexes K1 e2 and K1e2 only with ethene and
the catalytic activity for the polymerisation to polyethylene.
0
Complex K1 is an active catalyst for the polymerisation of
ethene yielding polyethylene [15]. In a standard 100 mL autoclave
setup we used the respective complex in a ca.10e15 mM solution in
dry toluene. We added ca. 70 bar ethene and stirred at room
temperature for 72 h. During that time, all of the ethene was
consumed and reacted to polyethylene [15]. The same reaction
0
procedure was applied to the other catalysts, K1, K2 and K2 .
However, none of them yielded polyethylene. GC/MS analysis of the
solutions after the catalysis experiments showed oligomers of
ethene, ranging from the ethene dimer butene (C4H8) up to several
isomers of hexadecene (C16H32), clearly identifiable by their frag-
mentation pattern in the EI mass spectra. Other reaction products
detected by GC/MS analysis are 2-methylstyrene and isomers of 1-
Fig. 4. Perspective view of complex K1. Displacement ellipsoids are drawn at the 30%
probability level.
but0enyl-2-methylbenzene in the case of the 2-toluenido complexes
0
(K1 and K2 ) or 2,4,6-trimethylstyrene, isomers of 1-butenyl-2,4,6-
trimethylbenzene and even small amounts of isomers of 1-(hex-
enyl)-2,4,6-trimethylbenzene in the case of the mesitylenido
complexes (K1 and K2). From the existence of different oligomers
with either hydrogen or the arenido ligand as end group can be
concluded that ethene does not only insert into the nickelecarbon
bond of the initial complex but also into the nickelehydrogen bond
nickelehydride complex reacts on towards paramagnetic decom-
position products [15]. 0
While complex K1 catalyses both the copolymerisation of
ethene and carbon monoxide as well as the polymerisation of
ethene, complex K1 is only active for the copolymerisation reaction
and merely forms oligomers in the reaction with ethene.
0
Complexes K2 and K2 are neither active in the copolymerisation
of the nickel hydride complex that is formed after
elimination of the insertion product. We confirmed
b
b
-hydride
-hydride
nor in the polymerisation. The ability for inserting ethene conforms
0
to the reactivity for the insertion of carbon monoxide. K1 easily
elimination as the beginning of the decomposition reaction and
thus as the start of the termination of the oligomerisation reaction
inserts carbon monoxide at atmospheric pressure whereas the
0
by means of investigating the reaction of the complexes K1 and K1
insertion of CO into the NieC bond of K1 only takes place in a 5 bar
with olefins and alkynes as recently published [15].
carbon monoxide atmosphere. This is reflected in the reactivity of
0
the two complexes towards ethene. While K1 polymerises ethene
To sustain a constant insertion of ethene into the nickelecarbon
bond (or the nickelehydrogen bond) a certain pressure of ethene is
needed. As long as the pressure of ethene is high enough the
insertion rate is higher than the b-hydride elimination rate and
oligomers of ethene are formed. When the insertion rate decreases
during the progress of the reaction a competition of ethene inser-
tion and b-hydride elimination starts. The b-hydride elimination
rate increases and eventually the insertion of ethene and thus the
formation of oligomers or even polymers is terminated as the
to yield polyethylene, K1 only produces ethene oligomers.
These observations lead us to the profound examination of both
the protonated ligand molecules HL1e3 as well as the complexes
K1e3. We determined the crystal structure of all six compounds
(Figs. 3e6).
Considering the data of Table 1 there are no obvious trends in
bond lengths and angles in the solid state that follow the observed
trend in catalytic activity. Again, no trend can be followed regarding
Fig. 3. Perspective view of HL1, HL2 and HL3. Displacement ellipsoids are drawn at the 30% probability level. Dashed lines indicate the directions of hydrogen bonding. The C3F7
group of HL3 is disordered over two positions with only one of them being shown.

76
U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
the n(C^N) stretching frequency in the IR spectra of the protonated
and coordinated ligands (see Table 1).
Both the protonated ligands and the nickel complexes contain
a delocalised
p-system for which two resonance structures are
relevant as depicted in Scheme 2. The contribution of the resonance
structures in the ligands and the complexes is different with
structure A seemingly being predominant in the ligands and
structure B contributing more to the complexes. Apart from that
the length of the N1eC30 bond does not change when considering
the 3s-criterion.
The only trend in the series K1e3 is observed in the intersection
angle of the corresponding NeOePeC mean plane with the ligand’s
NeCeC(CN)eCeO mean plane (Table 2, last row). With increasing
ring size (n ¼ 1e3) the intersection angle becomes larger as well,
describing the non-coplanarity of the ligand framework with the
square-planar coordination plane.
The increasing intersection angle could suggest that the N,O-
ligand in the case of K2 and K3 takes on conformations in solution
which make the approach and the coordination of a monomer
difficult and might hinder the insertion into the nickelecarbon
bond thus preventing the formation of polymer. Mechanistically
the coordination of a monomer can follow either an associative or
a dissociative pathway. In the associative case the monomer coor-
dinates to the axial position of the square-planar nickel complex
forming a square-pyramidal intermediate with the coordination
number 5 which then rearranges via Berry pseudo-rotation to
a trigonal-bipyramidal species that allows the insertion of the
monomer into the nickelecarbon bond from a position cis to the
arenido ligand. In the dissociative case one of the coordinated
ligands, here presumably triphenylphosphane, would dissociate so
that a species with a trifold coordination and a vacant coordination
site for the monomer is formed. As previous experiments with
triphenylphosphane added to the catalysis experiment showed [16]
free PPh3 has no influence on the catalytic activity thus indicating
an associative pathway which is also suggested by the trans-effect
of the triphenylphosphane ligand and the nitrogen atom of the N,O-
chelating ligand. Furthermore the addition of Lewis acids such as
triphenylborane and B(C6F5)3 which can act as phosphane scav-
engers show no difference in long-term catalytic runs as previously
described [16].
Fig. 5. Perspective view of complex K2. Displacement ellipsoids are drawn at the 30%
probability level.
Dissociation of triphenylphosphane therefore is not necessary to
enable catalytic activity and the difficulties in the polymerisation
can be more likely attributed to a hindrance in monomer coordi-
nation and insertion. In contrary the dissociation of the triphenyl-
phosphane ligand rather leads to decomposition of the catalyst
complex.
Fig. 6. Perspective view of complex K3. Displacement ellipsoids are drawn at the 30%
probability level.
In the case of a hindered approach and insertion of the mono-
mers in solution the insertion rate of ethene will be lower and
either no insertion at all takes place or e insertion presumed e
Table 1
Comparison of bond lengths (Å) and angles (ꢁ) in the protonated ligands HL1e3 with the corresponding data in the complexes K1e3 (see Figs. 3e6). For the disordered parts of K3
0
0
mean values are given. IR n
(C^N) stretching frequency (cmꢀ1, KBr disk) in HL1e3, K1e3 and K1 e3 . Data for HL1e3 see Ref. [13].
0
0
0
HL1
HL2
HL3
K1
K2
K3
K1 [12]
K2
K3
N1eC30
C30eC29
C29eC28
C28eO1
C29eC31
C31eN2
O1/Xa
1.303(2)
1.405(3)
1.413(3)
1.231(2)
1.414(3)
1.141(2)
2.06(2)
1.299(3)
1.424(3)
1.428(3)
1.228(3)
1.426(4)
1.145(3)
2.02(3)
0.84(3)
2.673(2)
133(3)
1.308(4)
1.429(4)
1.434(6)
1.232(6)
1.427(5)
1.133(4)
1.98(5)
0.81(4)
2.65(2)
139(4)
1.290(4)
1.421(4)
1.368(4)
1.252(3)
1.436(4)
1.124(4)
1.915(2)
1.903(3)
2.735(4)
91.51(9)
2217
1.300(4)
1.435(5)
1.383(5)
1.266(4)
1.438(5)
1.131(4)
1.904(2)
1.947(3)
2.763(5)
91.86(11)
2211
1.301(3)
1.448(3)
1.376(3)
1.260(3)
1.430(3)
1.137(3)
1.9206(16)
1.9460(19)
2.715(4)
89.17(7)
2206
1.299(3)
1.438(4)
1.387(3)
1.267(3)
1.443(4)
1.135(5)
1.918(2)
1.926(2)
2.744(3)
91.1(1)
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
N1/Xa
0.86(2)
N1/O1
2.685(2)
128.6(19)
2213
N1/X/O1a,b
n(C^N)
2206
2209
2216
2208
2226
a
X ¼ H1 or Ni1.
“bite angle”.
b

U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
77
polymerise ethene to polyethylene [15]. Reasons for this behaviour
can be assumed in a decreasing insertion rate of ethene during the
reaction, while b-hydride elimination takes over eventually leading
to the decomposition of the catalyst [15]. The crystal structures of
the complexes were determined in the search for information on
a molecular basis. With an increasing heterocyclic ring size the
intersection angle between the ligand framework and the square-
planar coordination plane increases as well. This finding in solid
state might be an approach to further understand the different
catalytic behaviour. In solution this seems to lead to conformations
that hinder the approach and coordination of monomers.
Scheme 2. The two resonance structures contributing to both the ligands HL1e3 and
the complexes K1e3 with A contributing more to the ligands and B contributing more
to the complexes.
4. Experimental section
Table 2
0
Comparison of bond lengths (Å) and angles (ꢁ) of complexes K1e3 and K1 .
All reactions were carried out under nitrogen atmosphere using
standard Schlenk techniques unless stated otherwise. All solvents
were purified and degassed by standard procedures. Chemicals
were bought from commercial sources like Acros, SigmaeAldrich,
Merck and Fluorochem. One-dimensional NMR spectra were
recorded at room temperature, 1H and 31P{1H} NMR spectra were
recorded on a Bruker Avance DRX 200 spectrometer, and 13C and
19F NMR spectra were recorded on a Bruker Avance DRX 500
spectrometer. The proton chemical shifts are given in ppm and
referenced to the signal of TMS or the solvent residual signal [17]
(CD2Cl2: 1H 5.30 ppm, C6D6: 1H 7.16 ppm, 13C 128.1 ppm, CDCl3:
7.26 ppm). The fluorine chemical shifts are referenced to C6F6
0
K1 [12]
K1
K2
K3
NieP
NieC
2.1935(10) 2.1854(9) 2.1958(10) 2.1828(7)
1.893(2)
0.03
1.884(3)
0.03
1.886(4)
0.04
1.892(2)
0.03
Ni raised out of the
NeOePeC mean plane
Intersection angle of the
CeNieP plane with the
NeNieO plane
Intersection angle of the
mesitylenido mean
plane with the NeOePeC
mean plane
Intersection angle of the
NeOePeC mean plane
with the ligand NeCeC
(CN)eCeO mean plane
2.5
8.0
7.2
3.7
88.5
83.3
83.2
88.8
0.9
12.4
21.2
37.5
(
19F ꢀ162.9 ppm) [18], the phosphorous chemical shifts are refer-
enced to the signal of external H3PO4 (85%). The coupling constants
are reported as their absolute value. Infrared spectra were recorded
on a FT-IR Bruker IFS 66 spectrometer. Elemental analyses were
performed on a PerkineElmer CHN-2400/II elemental analyser.
GC/MS spectra were determined on a Thermo Finnigan Trace
GC-Ultra Trace DSQ comprising a column of 15 m length with
0.25 mm in diameter and a DB5MS phase. Injection temperature
was 220 ꢁC, column temperature increased starting at 50 up to
250 ꢁC with 20 ꢁC minꢀ1. % Area is listed as intensity of the signal in
the gas chromatogram. (SP-4-3)-[NiBr(2-tol)(PPh3)2] and (SP-4-3)-
[NiBr(mes)(PPh3)2] were prepared according to modified literature
procedures [14,19e21]. The preparation of the protonated ligands
HL1e3 was reported previously [13]. Single crystals of HL1e3 suitable
for X-ray diffraction were obtained by slow evaporation of a satu-
rated diethyl ether solution of each ligand HL1e3. The synthesis of
eventually
b-hydride elimination will take over leading to the
decomposition of the catalyst. Evidence for no insertion of the
monomers is found in the gas chromatogram of the solution after
the catalysis experiment of K2 with ethene. Mesitylene, the N,O-
ligand HL2 and triphenylphosphane are detected. The appearance
of these compounds in the gas chromatogram is due to the
decomposition of the intact catalyst complex on the GC column.
The decomposition of the complexes has been separately investi-
gated by measuring a gas chromatogram of a freshly prepared
toluene solution of K1 which showed the single components
mesitylene, the N,O-ligand HL1 and triphenylphosphane as
decomposition products. The protonation of the mesitylenido
ligand and the N,O-ligand results from protonation by the slightly
10
(SP-4-3)-[Ni(L1)(2-tol)(PPh3)] K was carried out as described
previously [14].
acidic column.
0
Comparison of the complexes K1 and K1 also suggests a steric
4.1. (SP-4-3)-[Ni(L1)(mes)(PPh3)] (K1)
hindrance effect of the two ortho methyl groups at the mesityle-
0
nido ligand (K1) compared to the 2-toluenido analogue (K1 ) with
The synthesis was carried out as previously described [14].
Single crystals of the complex suitable for X-ray diffraction were
obtained upon cooling by slow crystallisation from hot methanol.
respect to monomer insertion.
Theoretical calculations are underway to better understand the
described effects.
4.2. (SP-4-3)-[Ni(L2)(mes)(PPh3)] (K2)
3. Conclusions
382 mg (1.2 mmol) of 4,4,5,5,6,6,6-heptafluoro-3-oxo-2-
piperidin-(2Z)-ylidene-hexanenitrile (HL2) were dissolved in
50 mL toluene. 2.0 mL (1.2 mmol) of sodium bis(trimethylsilyl)
amide (0.6 M in toluene) was added and the mixture was stirred for
2 h. A solution of 939 mg (1.2 mmol) of (SP-4-3)-[NiBr(mes)(PPh3)2]
[14] in 50 mL toluene was added dropwise with stirring. After
complete addition stirring was continued overnight and the reac-
tion mixture was filtered over celiteÒ. The solvent was removed in
vacuo and to the residue was added 20 mL pentane. After stirring
overnight, the yellow precipitate was filtered, washed with pentane
and dried in vacuo yielding 572 mg (63%) of K2. Single crystals
suitable for X-ray diffraction were obtained by slow diffusion of
0
The nickel complexes K1 and K1 comprising a N,O-chelate
ligand with a five-membered heterocycle are catalysts for the
copolymerisation of ethene and carbon monoxide [12,14]. We re-
ported new nickel complexes in which the five-membered
heterocycle of the bidentate N,O-ligand was altered to six- and
0
0
seven-membered rings, K2, K2 , K3 and K3 . All four were tested as
catalysts for the copolymerisation reaction of ethene and carbon
monoxide, but unexpectedly none of them showed catalytic
activity for the polymerisation reaction. Catalysis experiments with
ethene yielded oligomers and products containing the arenido
0
ligand and several ethene units whereas K1 was found to

78
U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
a pentane/hexane mixture (1:1) into a concentrated solution of K2
in toluene. 1H NMR (500.13 MHz, CD2Cl2, r.t., ppm):
[ABMX]2, 2H, CH2); 1.57 (M of [ABMX]2, 2H, CH2); 2.02 (s, 3H, p-
CH3); 2.61 (B of [ABMX]2, 2H, CH2); 2.65 (A of [ABMX]2, 2H, CH2);
2.78 (s, 6H, o-CH3); 6.12 (s, 2H, mes); 7.20 (C of [A[BC]2], 6H, PPh3);
7.28 (B of [A[BC]2], 6H, PPh3); 7.35 (A of [A[BC]2], 3H, PPh3). 31P{1H}
(m, 1H, o-tol); 7.20e7.40 (m, 16H, PPh3 þ o-tol). 31P{1H} NMR
d
¼ 1.25 (X of
(202.46 MHz, CD2Cl2, r.t., ppm):
d
¼ 27.6. 19F NMR (470.55 MHz,
CD2Cl2, r.t., ppm): ꢀ80.9 (t, 4JFF ¼ 7 Hz, 3F, CF3); ꢀ115.1, ꢀ115.9 (dq,
4
2JFF ¼ 270 Hz, JFF ¼ 9 Hz, 2F, C(O)CF2); ꢀ126.0, ꢀ126.7 (d,
2
JFF ¼ 285 Hz, 2F, CF2eCF3). IR (KBr disk, cmꢀ1):
n
¼ 3021 (m, Ce
e
Haromat.); 2944 (m, CeHaliphat.); 2226 (vs, C^N); 1611 (vs, C]O);
1502 (vs, C]C); 1438 (m, PeC); 1230 (s, CeF). C36H30N2OF7PNi
(743.33): calcd. C 59.79, H 4.34, N 3.77; found C 59.4, H 4.4, N 4.0.
NMR (202.46 MHz, CD2Cl2, r.t., ppm):
(470.54 MHz, CD2Cl2, r.t., ppm):
d
¼
24.0. 19F NMR
4
d
¼ ꢀ81.6 (t, JFF ¼ 9.4 Hz,
4
CF3); ꢀ115.2 (q, JFF ¼ 9.4 Hz, COCF2); ꢀ126.5 (s, CF2eCF3). IR (KBr
disk, cmꢀ1):
n
¼ 3053 (m, CeHaromat.); 2940 (m, CeHaliphat.); 2211
4.6. (SP-4-3)-[NiBr(2,4-xyl)(PPh3)2]
e
(vs, C^N); 1590 (vs, C]O); 1576 (vs, C]C); 1435 (m, PeC); 1228 (s,
CeF). C38H34N2OF7PNi (757.35): calcd. C 60.26, H 4.52, N 3.70;
found C 59.9, H 4.7, N 3.9.
The synthesis was carried out as for (SP-4-3)-[NiBr(2-tol)(PPh3)2],
except that 4.6 g (25 mmol) 2,4-dimethylbromobenzene was used
yielding 8.6 g of a yellow solid (56%).1H NMR (200.13 MHz, CDCl3, r.t.,
0
4.3. (SP-4-3)-[Ni(L2)(2-tol)(PPh3)] (K2 )
ppm):
d
¼1.92(s, 3H,p-CH3), 2.02(s, 3H, o-CH3), 5.80 (s,1H, m-CHxyl,
between the methyl groups), 6.12 (d,1H, m-CH xyl), 6.87 (d,1H, o-CH
The synthesis was carried out as for K2, except that 902 mg
xyl), 7.22 (m, 18H, PPh3), 7.53 (m, 12H, PPh3). 13C{1H} NMR
(1.2 mmol) of (SP-4-3)-[NiBr(2-tol)(PPh3)2] was used. Yield: 430 mg
(125.77 MHz, C6D6, r.t., ppm, not all carbons observed):
d
¼ 20.7
0
(49%) of K2 . Single crystals suitable for X-ray diffraction were ob-
(p-CH3), 26.5 (o-CH3), 125.0 (m-CH xyl), 130.0, 131.6, 132.0, 132.7 (d,
tained by slow diffusion of a 0pentane/hexane mixture (1:1) into
2JCP ¼ 8.82 Hz), 144.0. 31P{1H} NMR (81.01 MHz, CDCl3, r.t., ppm):
a concentrated solution of K2 in toluene. 1H NMR (500.13 MHz,
d
¼ 22.5. IR (KBr disk, cmꢀ1):
n
¼ 3048 (w, CeHaromat.), 2914 (w, Ce
e
CD2Cl2, r.t., ppm):
d
¼ 1.26 (X of [ABMX]2, 2H, CH2); 1.57 (M of
Haliphat.), 1480 (m, CeCaromat.), 1434, 1384, 1308 (s, CeHaliphat.), 1093
(m, PeC), 741 (m, CeHaromat.). MS (FABþ): m/z (fragment/relative
intensity) ¼ 582 ([M ꢀ o,o-xyl ꢀ Br]þ,13), 367 ([o,o-xylePPh3]þ, 50),
307 (13), 289 (12), 262 ([PPh3]þ, 7), 154 (97), 136 (100), 105 ([o,o-
xyl]þ, 23), 89(81), 77 ([Ph]þ, 84), 63 (73), 51 (79). Thiscompound was
used without further purification.
[ABMX]2, 2H, CH2); 2.63 (A of [ABMX]2, B of [ABMX]2, o-CH3, 7H);
6.33 (m, 1H, o-tol); 6.45 (m, 1H, o-tol); 6.53 (m, 1H, o-tol); 7.24e7.39
(m,16H, PPh3 þ o-tol). 31P{1H} NMR (202.46 MHz, CD2Cl2, r.t., ppm):
d
¼ 27.2.19F NMR (470.55 MHz, CD2Cl2, r.t., ppm): ꢀ81.6(t, 4JFF ¼ 7 Hz,
2
4
3F, CF3); ꢀ115.0, ꢀ115.8 (dq, JFF ¼ 273 Hz, JFF ¼ 9 Hz, 2F, C(O)
2
CF2); ꢀ126.2, ꢀ126.8 (d, JFF ¼ 286 Hz, 2F, CF2eCF3). IR (KBr disk,
00
cmꢀ1):
n
¼ 3053 (m, CeHaromat.); 2941 (m, CeHaliphat.); 2208
4.7. (SP-4-3)-[Ni(L1)(2,4-xyl)(PPh3)] (K1
)
e
(vs, C^N); 1590 (vs, C]O); 1577 (vs, C]C); 1435 (m, PeC); 1229 (s,
CeF). C36H30N2OF7PNi (729.30): calcd. C 59.29, H 4.15, N 3.84; found
C 59.2, H 3.9, N 3.9.
3.37 g (4.38 mmol) (SP-4-3)-[NiBr(2,4-xyl)(PPh3)2] and 1.33 g
(4.38 mmol) 4,4,5,5,6,6,6-heptafluoro-3-oxo-2-[pyrrolidin-(2Z)-
ylidene]hexanenitrile (HL1) were dissolved in toluene (150 mL).
7.9 mL (4.38 mmol) Sodiumbis(trimethylsilyl)amide (0.6 M in
toluene) was added and the reaction mixture stirred overnight. After
filtration over celiteÒ the solvent was removed in vacuo and 150 mL
methanol was added to the residue. After stirring overnight, the
4.4. (SP-4-3)-[Ni(L3)(mes)(PPh3)] (K3)
The synthesis was carried out as for K2, except that 399 mg
(1.2 mmol) of 2-azepan-(2Z)-ylidene-4,4,5,5,6,6,6-heptafluoro-3-
oxo-hexanenitrile (HL3) was used. Yield: 722 mg (78%). Single
crystals suitable for X-ray diffraction were obtained by slow diffu-
sion of a pentane/hexane mixture (1:1) into a concentrated solution
yellow precipitate was filtered, washed with methanol and dried in
00
vacuo yielding 0.87 g of K1 (27%). 1H NMR (500.13 MHz, C6D6, r.t.,
ppm):
d
¼ 0.82 (m, 2H, CH2eCH2eCH2), 2.10 (s, 3H, p-CH3), 2.36 (m,
of K3 in toluene. 1H NMR (500.13 MHz, CD2Cl2, r.t., ppm):
d
¼ 0.97
2H, CH2eCH2eCH2), 2.63 (s, 3H, o-CH3), 2.69 (t, 2H, CH2eCH2eCH2),
6.34 (s,1H, m-CH xyl), 6.42 (s,1H, m-CH xyl), 6.94 (m, 9H, PPh3), 7.31
(s,1H, o-CH xyl), 7.44 (m, 6H, PPh3).13C{1H} NMR (125.77 MHz, C6D6,
(X of [ADMNX]2, 2H, CH2); 1.53 (M and N of [ADMNX]2, 4H, (CH2)2);
2.01 (s, 3H, p-CH3); 2.79 (s, 6H, o-CH3); 2.92 (D of [ADMNX]2, 2H,
CH2); 3.08 (A of [ADMNX]2, 2H, CH2); 6.12 (s, 2H, mes); 7.21 (C of [A
[BC]2], 6H, PPh3); 7.28 (B of [A[BC]2], 6H, PPh3); 7.36 (A of [A[BC]2],
r.t., ppm, not all carbons observed):
d
¼ 20.0 (CH2eCH2eCH2), 20.6
(p-CH3), 25.5 (o-CH3), 38.9 (CH2eCH2eCH2), 63.6 (CH2eCH2eCH2),
83.8 (C]CeCN), 125.0 and 129.9 (m-CH xyl), 130.3 (m-CH PPh3),
130.4 (p-CH PPh3), 134.5 (d, 2JCP ¼ 10.1 Hz, o-CH PPh3), 166.1 (C]O),
172.2 (C]CeCN). 31P{1H} NMR (202.46 MHz, C6D6, r.t., ppm):
3H, PPh3). 31P{1H} NMR (202.46 MHz, CD2Cl2, r.t., ppm):
d
¼ 23.6.
19F NMR (470.54 MHz, CD2Cl2, r.t., ppm):
d
¼ ꢀ81.7 (t, 4JFF ¼ 9.4 Hz,
4
CF3); ꢀ115.1 (q, JFF ¼ 9.4 Hz, COCF2); ꢀ126.8 (s, CF2eCF3). IR (KBr
disk, cmꢀ1):
n
¼ 3023 (m, CeHaromat.); 2935 (m, CeHaliphat.); 2206
d
¼ 27.5. 19F NMR (470.55 MHz, C6D6, r.t., ppm):
d
¼ ꢀ80.98 (t, 3F,
e
(vs, C^N); 1585 (vs, C]O); 1506 (vs, C]C); 1437 (m, PeC); 1228 (s,
CeF). C39H36N2OF7PNi (771.38): calcd. C 60.73, H 4.70, N 3.63;
found C 61.0, H 4.8, N 3.5.
CF3), ꢀ115.40 (q, 2F, C(O)CF2), ꢀ125.79 (t, 2F, CF2eCF3). IR (KBr disk,
cmꢀ1):
n
¼ 3056 (w, CeHaromat.), 2982 (w, CeHaliphat.), 2214 (s, C^N),
e
1591 (vs, C]O), 1516 (s, CeCaromat.), 1434 (s, CeHaliphat.), 1260, 1229,
1183 (s, CeF), 1114 (m, PeC), 750 (m, CeHaromat.). MS (FABþ): m/z
(fragment, relative intensity) ¼ 730 ([M]ꢂþ, 1%), 729 ([M ꢀ H]þ, 2),
368 (31), 367 ([o,p-xylePPh3]þ, 100), 307 (15), 289 (10), 263
([HPPh3]þ, 10), 262 ([PPh3]þ, 8).
0
4.5. (SP-4-3)-[Ni(L3)(2-tol)(PPh3)] (K3 )
The synthesis was carried out as for K2, except that 902 mg
(1.2 mmol) of (SP-4-3)-[NiBr(2-tol)(PPh3)2] and 399 mg (1.2 mmol)
of
2-azepan-(2Z)-ylidene-4,4,5,5,6,6,6-heptafluoro-3-oxo-hex-
4.8. (SP-4-3)-[NiBr(2,6-xyl)(PPh3)2]
0
anenitrile (HL3) were used. Yield: 410 mg (46%) of K3 . Single
crystals suitable for X-ray diffraction were obtained by slow diffu-
The synthesis was carried out as for (SP-4-3)-[NiBr(2-tol)(PPh3)2],
except that 4.6 g (25 mmol) 2,6-dimethylbromobenzene was used
yielding 7.9 g of a yellow solid (51%).1H NMR (200.13 MHz, CDCl3, r.t.,
sion of a pentane/hexane mixture (1:1) into a concentrated solution
0
of K3 in toluene. 1H NMR (500.13 MHz, CD2Cl2, r.t., ppm):
d
¼ 0.96
(X of [ADMNX]2, 2H, CH2); 1.53 (M and N of [ADMNX]2, 4H, (CH2)2);
2.60 (s, 3H, o-CH3); 2.90 (D of [ADMNX]2, 2H, CH2); 3.05 (A of
[ADMNX]2, 2H, CH2); 6.30 (m, 1H, o-tol); 6.46 (m, 1H, o-tol); 6.51
ppm):
xyl), 7.28 (m, 15H, PPh3), 7.55 (m, 13H, PPh3), 7.75 (m, 2H, PPh3). 13
{1H} NMR (125.77 MHz, C6D6, r.t., ppm, not all carbons observed):
d
¼ 2.48 (s, 6H, CH3), 5.96 (d, 2H, m-CH xyl), 6.28 (t, 1H, p-CH
C

U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
79
d
¼ 26.8 (o-CH3 xyl), 124.0 (p-CH xyl), 126.6 (m-CH xyl), 130.0, 131.9,
13), 157 ([M
ꢀ
C2H5]þ, 100), 143 ([M
ꢀ
C3H7]þ, 17), 142
ꢂ
133.4, 143.2. 31P{1H} NMR (81.01 MHz, CDCl3, r.t., ppm):
d
¼ 21.5. IR
([M ꢀ C3H8]ꢂþ, 56), 129 ([M ꢀ C4H9]þ, 13), 128 ([M ꢀ C4H10
115 ([M ꢀ C5H11]þ, 14).
]
þ, 16),
(KBr disk, cmꢀ1):
n
¼ 3140, 3051, 3002 (m, CeHaromat.), 2984, 2952,
e
2900 (w, CeHaliphat.), 1480 (m, CeCaromat.), 1433, 1386, 1307 (vs, Ce
Haliphat.), 1091 (s, PeC), 750, 740 (s, CeHaromat.). MS (FABþ): m/z
(fragment/relative intensity) ¼ 582 ([M ꢀ o,o-xyl ꢀ Br]þ, 2), 367
([o,o-xylePPh3]þ, 3), 307 (10), 289 (9), 154 (90), 136 (100), 105 ([o,o-
xyl]þ, 24), 89(92), 77([Ph]þ, 96), 63(86), 50(92). Thiscompound was
used without further purification.
4,6-Dimethyl-3-propyl-1H-indene
Retention time: 6.97 min; MS (EI): m/z (fragment, relative
intensity) 186 ([M]ꢂþ,100%),171 ([M ꢀ CH3]þ, 34), 157 ([M ꢀ C2H5]þ,
48), 143 ([M
ꢀ
C3H7]þ, 93), 142 ([M
ꢀ
C3H8]ꢂþ
, 55), 129
ꢂ
([M ꢀ C4H9]þ, 41), 128 ([M ꢀ C4H10
]
þ, 62), 115 ([M ꢀ C5H11]þ, 34).
000
4.9. (SP-4-3)-[Ni(L1)(2,6-xyl)(PPh3)] (K1
)
4.11. Catalysis experiments with carbon monoxide and ethene
00
The synthesis was carried out as for K1 except that 2.92 g
(4.00 mmol) (SP-4-3)-[NiBr(2,6-xyl)(PPh3)2], 1.22 g (4.00 mmol)
HL1 and 7.2 mL (4.00 mmol) sodium bis(trimethylsilyl)amide were
used, yielding 2.09 g of a yellow solid (72%). 1H NMR (500.13 MHz,
20 mg of the catalyst complex was dissolved in toluene (10 mL)
in a 100 mL stainless steel autoclave with glass inlet under nitrogen
atmosphere. Ethene (40 bar) and carbon monoxide (10 bar) were
added and the reaction mixture was stirred for 24 h at 60 ꢁC. The
autoclave was weighed before and after adding the gases to
determine the mass of the gases. If a solid precipitate formed this
solid was separated, washed with methanol, dried in vacuo and
characterised by IR spectroscopy.
C6D6, r.t., ppm):
d
¼ 0.82 (m, 2H, CH2eCH2eCH2), 2.39 (m, 2H, CH2e
CH2eCH2), 2.58 (t, 2H, CH2eCH2eCH2), 2.87 (s, 6H, o-CH3), 6.42 (d,
2H, m-CH xyl), 6.70 (t,1H, p-CH xyl), 6.92 (m, 9H, PPh3), 7.38 (m, 6H,
PPh3). 13C{1H} NMR (125.77 MHz, C6D6, r.t., ppm, not all carbons
observed):
d
¼ 20.2 (CH2eCH2eCH2), 25.9 (CH3), 38.9 (CH2eCH2e
CH2), 63.3 (CH2eCH2eCH2), 124.3 (p-CH xyl), 125.5 (m-CH xyl),
4.12. Catalysis experiments with ethene
3
130.3 (d, JCP ¼ 2.5 Hz, m-CH PPh3), 130.7 (p-CH PPh3), 134.3 (d,
2JCP ¼ 10.1 Hz, o-CH PPh3), 142.3 (d, 3JCP ¼ 2.5 Hz, o-C xyl), 148.9 (d,
70mgof the complexwere dissolvedindegassed and driedtoluene
(6 mL) in a stainless steel autoclave with glass inlet under nitrogen
atmosphere and stirred for several days under a pressure of 70 bar of
ethene. A GC/MS spectrum of the remaining solution was recorded.
2JCP ¼ 50.4 Hz, i-C xyl), 166.1 (C]O), 172.6 (C]CeCN). 31P{1H} NMR
(202.46 MHz, C6D6, r.t., ppm):
d
¼ 25.4. 19F NMR (470.55 MHz, C6D6,
r.t., ppm):
d
¼ ꢀ81.00 (t, 3F, CF3), ꢀ115.13 (m, 2F, C(O)CF2), ꢀ125.51
(t, 2F, CF2eCF3). IR (KBr disk, cmꢀ1):
n
¼ 3054 (w, CeHaromat.), 2955,
e
0
2907 (w, CeHaliphat.), 2214 (s, C^N), 1586 (vs, C]O), 1512 (s, Ce
Caromat.), 1435 (s, CeHaliphat.), 1260, 1230, 1193 (vs, CeF), 1110 (s,
PeC), 742 (m, CeHaromat.). MS (EI): m/z (fragment, relative
intensity) ¼ 368 (26), 367 ([o,o-xylePPh3]þ,100), 263 ([HPPh3]þ, 8),
262 ([PPh3]þ, 34), 183 (28), 108 (7). MS (MALDI): m/z ¼ 561
([M ꢀ C3F7]þ), 508, 367 ([o,o-xylePPh3]þ), 279, 263 ([HPPh3]þ),
228. C36H30F7N2OPNi (730.30): calcd. C 59.20, H 4.15, N 3.83; found
C 59.0, H 4.2, N 3.8.
4.12.1. K1 /ethene only
Polyethylene yield 82%.
GC/MS: 3.0 min (26%, ethene oligomer C10H20), 3.1 min (18%,
ethene oligomer C10H20 and 2-methylstyrene, signals are not
properly separated), 3.2 min (7%, ethene oligomer C10H20), 4.0 min
(1%, isomer of 1-(butenyl)-2-methylstyrene and ethene oligomer
C12H24, signals are not properly separated), 4.3 min (4%, isomer of
1-(butenyl)-2-methylstyrene), 4.6 min (6%, ethene oligomer
C12H24), 4.7 min (2%, isomer of 1-(butenyl)-2-methylstyrene and
ethene oligomer C12H24, signals are not properly separated),
4.8 min (1%, ethene oligomer C12H24), 6.0 min (1%, ethene oligomer
C14H18), 7.3 min (1%, ethene oligomer C16H32), 10.3 min (5%,
triphenylphosphane).
4.10. Decomposition experiments with 2-hexyne
The reaction of the complexes with 2-hexyne was carried out as
previously described [15]. For GC/MS data of the reaction of K1 and
0
K1 with 2-hexyne see Ref. [15].
4.12.2. K1/ethene only
GC/MS (gaseous phase): 0.5 min (34%, ethene dimer/butene
C4H8), 0.7 min (48%, ethene trimer/hexene C6H12), 1.9 min (2%,
ethene tetramer/octene C8H16).
4.10.1. Reaction of K1’’ with 2-hexyne
GC/MS: 4.8 min (7%, 2,4-dimethylphenol), 6.25 min (2%,
b
-hydride elimination product 3-(2,4-dimethylphenyl)-1,2-
hexadiene), 6.32 min (2%, -hydride elimination product 2-(2,4-
b
GC/MS (solution): 2.7 min (3%, ethene oligomer C10H20), 2.8 min
(2%, ethene oligomer C10H20), 2.9 min (4%, ethene oligomer C10H20),
3.0 min (22%, ethene oligomer C10H20 and mesitylene, signals are
not properly separated), 3.1 min (9%, ethene oligomer C10H20),
3.2 min (10%, ethene oligomer C10H20), 4.2 min (2%, ethene olig-
omer C12H24), 4.3 min (1%, ethene oligomer C12H24), 4.4 min (3%,
ethene oligomer C12H24), 4.5 min (2%, ethene oligomer C12H24),
4.6 min (9%, ethene oligomer C12H24), 4.7 min (4%, ethene oligomer
C12H24), 4.8 min (4%, ethene oligomer C12H24), 5.7 min (1%, ethene
oligomer C14H28), 5.9 min (1%, ethene oligomer C14H28), 6.0 min
(3%, ethene oligomer C14H18), 6.1 min (1%, isomer of 1-(butenyl)-
2,4,6-trimethylbenzene and ethene oligomer C14H28, signals are not
properly separated), 6.9, 7.0, 7.1 min (>1%, ethene oligomer C16H32),
7.2 min (2%, ethene oligomer C16H32), 8.0 min (>1%, N,O-ligand
HL1), 10.3 min (1%, triphenylphosphane).
dimethylphenyl)-2,3-hexadiene), 6.97 min (1%, rearrangement
product 4,6-dimethyl-3-propyl-1H-indene), 12.3 min (45%, triphe-
nylphosphane oxide).
2,4-Dimethylphenol
Retention time: 4.8 min; MS (EI): m/z (fragment, relative
intensity) 122 ([M]ꢂþ, 97%), 121 ([M ꢀ H]þ, 51), 107 ([M ꢀ CH3]þ,
100), 91 ([M ꢀ C2H7]þ, 19), 77 (Ph, 25).
3-(2,4-Dimethylphenyl)-1,2-hexadiene
Retention time: 6.25 min; MS (EI): m/z (fragment, relative
intensity) 186 ([M]ꢂþ, 4%), 158 ([M ꢀ C2H4]ꢂþ, 11), 157 ([M ꢀ C2H5]þ,
19), 143 ([M
ꢀ
C3H7]þ, 100), 129 ([M
ꢀ
C4H9]þ, 18), 128
ꢂ
([M ꢀ C4H10
]
þ, 52), 115 ([M ꢀ C5H11]þ, 15).
0
2-(2,4-Dimethylphenyl)-2,3-hexadiene
4.12.3. K2 /ethene only
Retention time: 6.32 min; MS (EI): m/z (fragment, relative
GC/MS: 2.7 min (2%, ethene oligomer C10H20), 2.8 min (2%,
ethene oligomer C10H20), 2.9 min (3%, ethene oligomer C10H20),
intensity) 186 ([M]ꢂþ, 2%), 171 ([M ꢀ CH3]þ, 8), 158 ([M ꢀ C2H4]ꢂþ
,

80
U. Beckmann et al. / Journal of Organometallic Chemistry 720 (2012) 73e80
3.0 min (10%, ethene oligomer C10H20), 3.1 min (14%, ethene olig-
omer C10H20 and 2-methylstyrene, signals are not properly sepa-
rated), 3.2 min (3%, ethene oligomer C10H20), 4.6 min (3%, ethene
oligomer C12H24), 4.7 min (1%, ethene oligomer C12H24), 4.75 min
(1%, ethene oligomer C12H24), 4.82 min (1%, isomer of 1-(butenyl)-
2-methylstyrene), 6.0 min (2%, ethene oligomer C14H18), 7.2 min
(1%, ethene oligomer C16H32), 10.3 min (1%, triphenylphosphane),
12.3 min (43%, triphenylphosphane oxide).
Acknowledgements
M.M.L. thanks the Studienstiftung des deutschen Volkes for
a Ph.D. scholarship. We thank E. Hammes for technical assistance
during X-ray data acquisition as well as Dr. P. Tommes and R. Bürgel
for MS data.
Appendix A. Supplementary material
4.12.4. K2/ethene only
CCDC 802018 (HL1), 802019 (HL2), 802020 (HL3), 802021 (K1),
802022 (K2) and 802023 (K3) contain the supplementary crystal-
lographic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
GC/MS (gaseous phase): 0.5 min (17%, ethene dimer/butene
C4H8), 0.7min(23%, ethenetrimer/hexeneC6H12),1.8min(1%, ethene
tetramer/octene C8H16).
GC/MS (solution): 2.7 min (6%, ethene oligomer C10H20), 2.8 min
(4%, ethene oligomer C10H20), 2.9 min (11%, ethene oligomer
C10H20), 3.0 min (17%, ethene oligomer C10H20 and mesitylene,
signals are not properly separated), 3.1 min (11%, ethene oligomer
C10H20), 4.3 min (1%, ethene oligomer C12H24), 4.4 min (0.5%, ethene
oligomer C12H24), 4.5 min (3%, trimethylstyrol), 4.6 min (1%, ethene
oligomer C12H24), 4.7 min (1%, ethene oligomer C12H24), 5.5 min
(1%, isomer of 1-(butenyl)-2,4,6-trimethylbenzene), 5.8 min (7%,
isomer of 1-(butenyl)-2,4,6-trimethylbenzene), 6.0 min (4%, isomer
of 1-(butenyl)-2,4,6-trimethylbenzene), 7.0 min (0.5%, isomer of
1-(hexenyl)-2,4,6-trimethylbenzene), 7.2 min (0.5%, isomer of
1-(hexenyl)-2,4,6-trimethylbenzene), 8.7 min (5%, N,O-ligand HL2),
10.3 min (10%, triphenylphosphane), 12.3 min (11%, triphenyl-
phosphane oxide).
Appendix B. Supplementary material
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.jorganchem.2012.08.030.
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4.12.5.2. Isomers of 1-(butenyl)-2,4,6-trimethylbenzene. Retention
time: 5.5 min; MS (EI): m/z (fragment, relative intensity) 174 ([M]ꢂþ
,
27), 173 ([M ꢀ H]þ, 12), 159 ([M ꢀ CH3]þ, 100), 147 (61), 144 ([M e
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Retention time: 5.8 min; MS (EI): m/z (fragment, relative
intensity) 174 ([M]ꢂþ, 62), 173 ([M ꢀ H]þ, 3), 159 ([M ꢀ CH3]þ, 100),
144 ([M ꢀ 2CH3]þ, 28), 131 (12), 129 (12), 128 (12), 119 (9), 117 (11),
105 (10).
Retention time: 6.0 min; MS (EI): m/z (fragment, relative intensity)
174 ([M]ꢂþ, 67), 173 ([M ꢀ H]þ, 2), 159 ([M ꢀ CH3]þ, 100), 144
([Mꢀ 2CH3]þ, 25),131 (13),129 (14),128 (13),120 (14),117 (12),105 (11).
ꢀ
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