η6-mesityl,η1-imidazolinylidene-carbene- ruthenium(II) complexes: Catalytic activity of their allenylidene derivatives in alkene metathesis and cycloisomerisation reactions

Article abstract of DOI:10.1002/chem.200204533

The reaction of electron-rich carbene-precursor olefins containing two imidazolinylidene moieties [(2,4,6- Me₃C₆H₂CH₂)NCH₂ CH₂N(R)C=]₂ (2a: R = CH₂CH₂OMe, 2

Full text of DOI:10.1002/chem.200204533

FULL PAPER
h6-Mesityl,h1-Imidazolinylidene Carbene Ruthenium(ii) Complexes:
Catalytic Activity of their Allenylidene Derivatives in Alkene Metathesis
and Cycloisomerisation Reactions
Bekir fietinkaya,*[a] Serpil Demir,[b] Ismail ÷zdemir,[b] LoÔc Toupet,[c] David Se¬meril,[d]
Christian Bruneau,[d] and Pierre H. Dixneuf*[d]
Abstract: The reaction of electron-rich
carbene-precursor olefins containing
two imidazolinylidene moieties [(2,4,6-
midazole frame 6 was isolated from an in
situ reaction between [RuCl2(p-cym-
ene)]2, the corresponding benzimidazo-
lium salt and cesium carbonate. On
heating, the RuCl2(imidazolinylidene)
(p-cymene) complex 8, with p-meth-
oxybenzyl pendent groups attached to
the N atoms, leads to intramolecular p-
cymene displacement and to the chelat-
ed h6-arene,h1-carbene complex 9. On
reaction with AgOTf and the propargyl-
sponding ruthenium allenylidene inter-
mediates (4 ! 10, 5 ! 11, 6 ! 12). The in
situ generated intermediates 10 12
were found to be active and selective
catalysts for ring-closing metathesis
(RCM) or cycloisomerisation reactions
depending on the nature of the
1,6-dienes. Two complexes [RuCl2-
{h1-CN(CH2C6H2Me3-2,4,6)CH2CH2N-
(CH2CH2OMe)}(C6Me6)] 3 with a mon-
odentate carbene ligand and [RuCl2{h1-
ˆ
Me3C6H2CH2)NCH2CH2N(R)C ]2 (2a:
R ˆ CH2CH2OMe, 2b R ˆ CH2Mes),
bearing at least one 2,4,6-trimethylben-
zyl (R ˆ CH2Mes) group on the nitrogen
atom, with [RuCl2(arene)]2 (arene ˆ p-
cymene, hexamethylbenzene) selective-
ly leads to two types of complexes. The
cleavage of the chloride bridges occurs
first to yield the expected (carbene)
(arene)ruthenium(ii) complex 3. Then a
further arene displacement reaction
takes place to give the chelated
h6-mesityl,h1-carbene ruthenium com-
plexes 4 and 5. An analogous h6-a-
rene,h1-carbene complex with a benzi-
ꢀ
ic alcohol HC CCPh2OH, compounds
CN[CH2(h6-C6H2Me3-2,4,6)]CH2CH2N-
(CH2C6H2Me3-2,4,6)}] 5 with a chelating
carbene arene ligand were character-
ised by X-ray crystallography.
4
6 were transformed into the corre-
Keywords: alkene metathesis
arenes carbenes catalysis
cycloisomerisation ¥ ruthenium
¥
¥
¥
¥
Introduction
[a] Prof. B. fietinkaya
Ege University, Faculty of Science, Chemistry Department
Bornova 35100 Izmir (Turkey)
Nucleophilic carbenes have been shown to behave as phos-
phine mimics[1] and N-heterocyclic carbenes of the 1,3-
imidazolylidene and 1,3-imidazolinylidene type are currently
used in transition metal chemistry as ancillary ligands.[2] This
Fax : (‡90)232-3888264
E-mail: fietinkaya@fenfak.ege.edu.tr
[b] S. Demir, Dr. I. ÷zdemir
Inˆn¸ University, Chemistry Department
44069 Malatya (Turkey)
is largely due to their recently revealed ability to create
5]
specific catalytic activity,[3
and attempts are currently
Fax : (‡90)422-3410037
E-mail: iozdemir@inonu.edu.tr
being made to modify the coordination sphere of the
metal with the hope of finding an even better applica-
tion profile. For instance, the replacement of one phos-
phine ligand from the alkene metathesis catalyst pre-
[c] Dr. L. Toupet
¡
¬
¬
Groupe Matiere Condensee et Materiaux
¬
UMR 6626 Universite de Rennes CNRS
¬
Universite de Rennes l, 35042 Rennes (France)
ˆ
ˆ
cursors RuCl2( CHPh)(PCy3)2 and RuCl2[ CHC6H4-
(o-OiPr)](PCy3) by sterically hindered N-heterocyclic car-
bene moieties was recently found to impart significant
increases in activity as well as stability in solution.[6, 7]
Substantial variations of these carbene basic structural motifs
promise that the performance and scope of the catalysts can
be properly adjusted.
Fax : (‡33)2-23-23-67-17
E-mail: loic.toupet@univ-rennes1.fr
¬
[d] Prof. P. H. Dixneuf, Dr. D. Semeril, Dr. C. Bruneau
Institut de Chimie de Rennes
¬
UMR 6509 Organometalliques et Catalyse CNRS
¬
Universite de Rennes 1, 35042 Rennes (France)
Fax : (‡33)2-23-23-69-39
E-mail: pierre.dixneuf@univ-rennes1.fr
Chem. Eur. J. 2003, 9, 2323 2330
DOI: 10.1002/chem.200204533
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2323

P. H. Dixneuf, B. fietinkaya et al.
FULL PAPER
Previous work from our research groups in this area has
focussed on the elaboration of olefins as electron-rich
heterocyclic carbene precursors to allow the formation of
chelating carbenes,[5] and on the rapidly developing chemistry
of h6-arene ruthenium(ii) complexes containing substituted
imidazolidin-2-ylidenes.[8] We have now considered the pos-
sibility of generating heterocyclic carbenes that have a
pendent arene group to evaluate their ability to chelate the
ruthenium atom, stabilise the complex or create catalytic
activity. We report here the study of the first mixed arene
imidazolidin-2-ylidene metal chelating complexes and their
transformation into catalysts, via ruthenium allenylidene
species, for both alkene ring-closing metathesis (RCM) and
the cycloisomerisation of dienes. A preliminary account of
some of these results has been published.[9]
N
1a : R = CH2CH2OMe
1b : R = CH2Mes
, Cl-
+
H
2
N
R
Mes : 2,4,6-Me3C6H2
i)
R
N
N
N
N
R
2a: R = CH2CH2OMe
2b: R = CH2Mes
Results and Discussion
The synthesis of heterocyclic carbene precursors 1 and 2,
bearing at least one 2,4,6-trimethylbenzyl group linked to a
nitrogen atom has been attempted, since the methylene group
linking the mesityl group to the carbene nitrogen atom was
expected to provide enough flexibility for the mesityl group to
coordinate a metal site at the same time as the carbene. The
4,5-dihydroimidazolium salts 1a and b were first prepared by
a similar procedure to that originally developed by Lappert
et al.[10] (Scheme 1). The 4,5-dihydroimidazolium salts 1 were
selectively dehydrochlorinated on deprotonation with NaH,
and the electron-rich olefins 2a and 2b were obtained in good
yield (85%). They possess a bisimidazolin-2-ylidene structure
with one (2a) or two (2b) trimethylbenzyl groups linked to a
nitrogen atom.
ii), iv)
ii), iii)
Ru
Ru
v)
N
Cl
N
Cl
Cl
Cl
N
R
N
R
4
5
R = CH2CH2OMe
R = CH2Mes
3
R = CH2CH2OMe
Scheme 1. Synthesis and reactivity of electron-rich olefins: i) NaH, THF;
The deprotonation reaction of the salt that leads to the
formation of the olefin 2 can be monitored by 13CNMR
spectroscopy. Thus, the resonance for the N-CH-N carbon in 1
(ca. 160 ppm) vanishes and the relatively high-field-shifted
resonance for the olefinic carbon atom appears at about
135 ppm. This observation excludes the existence of the stable
corresponding free carbene since their typical values fall in
the 210 240 ppm range.[11] Rather, this carbene dimerises
into olefin 2 as soon as formed.
Treatment of 2a, the source of an asymmetrical carbene,
with [RuCl2(C6Me6)]2 in boiling toluene for 4 h afforded the
expected carbene ruthenium(C6Me6) complex 3 in 78%
yield. By contrast, the reaction of the same precursor 2a with
[RuCl2(p-cymene)]2, under the same conditions led to com-
plex 4 in 84% yield. It contains the chelating mixed arene
carbene ligand, thus showing the facile displacement of the
p-cymene ligand at 1108C. Treatment of 2b with both [RuCl2-
(p-cymene)]2 and [RuCl2(C6Me6)]2 led to the formation of the
same complex 5 with one coordinated and one pendent
mesityl group. Thus, depending on the nature of both the
arene and olefin used, the derived carbene behaves as a
monodentate carbene ligand, bonded to the metal directly
through the carbene carbon atom (3) or as an 8-electron
polydentate ligand, bonded to the metal atom through both
the carbene carbon and the mesityl group, acting as a
chelating ligand (4 and 5). It is noticeable that the p-cymene
ii) [RuCl2(arene)]2 (arene ˆ p-MeC6H4CHMe2, C6Me6), 1008C, PhMe;
iii) [RuCl2(C6Me6)]2
‡
2a; iv) [RuCl2(p-cymene)]2
‡
2a or 2b, or
[RuCl2(C6Me6)]2 ‡ 2b; v) p-xylene, 1408C.
is displaced much more readily than the C6Me6 ligand.
Complex 3, however, can be converted to the chelated
product 4 on reflux in p-xylene (1408C); this is consistent
À
À
with a stronger C6Me6 Ru bond than p-cymene Ru bond.
These observations indicate that the first reaction step
consists of the conversion of the starting dinuclear ruthenium
complex to the mononuclear (arene)(carbene)ruthenium
complexes, such as 3, which upon further heating afford the
complexes 4 and 5 by substitution of the arene (p-cymene or
C6Me6) by the mesityl group attached to the carbene.
To examine whether this two-step transformation has a
more general character, the benzimidazolium salt[10] 7, which
gives a less electron-releasing carbene than the 4,5-dihydro-
imidazolium salts, was evaluated in the same type of reaction.
It is noteworthy that a different, more direct process was
attempted this time. It has recently been shown that heating
[RuCl2(p-cymene)]2, 4,5-dihydroimidazolium salt and Cs2CO3
in toluene afforded an in situ prepared catalyst for enyne or
alkene metathesis that was more active that the isolated
complex RuCl2(imidazolinylidene)(p-cymene).[12] It was sug-
gested that the catalyst resulted from the coordination of the
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Chem. Eur. J. 2003, 9, 2323 2330

Carbene Ruthenium(ii) Complexes
2323 2330
carbene, formed in situ on imidazolium-salt deprotonation
with Cs2CO3, with concomitant displacement of the (p-
cymene) ligand. Thus, the benzimidazolium salt 7 was heated
with [RuCl2(p-cymene)]2 in toluene at 1108Cfor 7 hours in
the presence of an excess of cesium carbonate. Complex 6,
with the mesityl group h6-coordinated to the ruthenium atom,
was obtained in 78% yield (Scheme 2). This result shows for
when a more electron-rich arene ligand is present, this may
lead to the preferential coordination of this arene group such
as in the transformations to 4, 5 and 9.
The above complexes, 4 6 and 9, are the first examples of
carbene ruthenium(ii) complexes containing a chelating
formal 8-electron arene carbene ligand. All of the new
products 3 6 and 9 were obtained as orange-brown crystal-
line complexes in good yields. They are air stable and soluble
in dichloromethane. Their structure was confirmed by NMR
and mass spectroscopy, elemental analysis and X-ray diffrac-
tion studies for 3 and 5.
The NMR spectra were particularly diagnostic as to the
nature of the bonding in these new complexes, establishing
that they have either ruthenium mesityl or pendent mesityl
groups. Thus, the chemical shifts of the metal-bound 2,4,6-
trimethylbenzyl protons in complexes 4 6 are found at higher
fields (Dd ˆ 1.4 ppm) than in the pendent 2,4,6-trimethylben-
zyl group. The 1H NMR spectra of 3 and 6 have two
resonances for the arene-ring protons, and the 13CNMR
spectra have six signals for the corresponding ring carbon
atoms. 1H,1H COSY and HETCOR NMR studies were
required to assign methylene signals in complexes 3 and 6.
The nonequivalence of each proton in both CH2 groups
indicates the absence of any symmetry element in the
complex, in perfect agreement with the solid-state structure.
The remarkable high-field 13CNMR resonances of the
carbene carbon atoms, in the 200 210 ppm range, are similar
to those observed for other ruthenium carbene com-
Ru
N
Cl
N
i)
Cl
, Cl-
H
N
+
N
O
7
O
6
Scheme 2. i) [RuCl2(p-cymene)]2, C sCO2, toluene, 1108C.
2
the first time that Cs2CO3 is able to generate a ruthenium-
coordinated imidazolylidene group from imidazolium salt in
refluxing toluene, as was postulated for the in situ generation
of carbene ruthenium(ii) catalysts,[12] and that the p-cymene
ligand can be easily displaced on heating.
Upon comparison with earlier work, a dramatic contrast
appears between the 1,3-imidazolin-2-ylidene carbene with
R ˆ CH2C6H5 and those arising from either 2a, 2b or 7 with
pendent CH2Mes groups in terms of their coordinative
behaviour towards [RuCl2(p-cymene)]2. The carbene derived
upon coordination to [RuCl2(p-cymene)]2 of the carbene-
precursor olefin with R ˆ CH2Ph is not able to further react in
an intramolecular manner to displace the p-cymene ligand.[5]
On the other hand, such a process occurs rather rapidly with
the carbene derived from 2b or 7 (R ˆ CH2Mes). Moreover,
study of the carbene complex 8,[13] with only one electron-
donating methoxy group on the benzyl substituent, has shown
that, on heating, it can be converted to complex 9, which
contains the chelating mixed arene carbene ligand, thus
p-cymene displacement occurs (Scheme 3).
plexes.[5, 8] The typical (carbene)C Ru carbon singlet for 3 is
ˆ
at lower field (210.26 ppm) than for the corresponding
chelated complex 4 (200.14 ppm). The CH2Mes substituent
on the second N atom of 5 does not show a noticeable effect
on the chemical shift (199.95 ppm).
X-ray structures: To gauge the steric factors at play with the
dangling and coordinated CH2Mes system, structural studies
were carried out on complexes 3[14] and 5.[15] ORTEP diagrams
of 3 and 5 with selected data are presented in Figures 1 and 2,
respectively. In both compounds, the ruthenium atoms have
pseudooctahedral geometry with the arene occupying three
adjacent sites of the octahedron. The most striking feature of 5
is that the carbene ring is almost orthogonal to the coordi-
nated 2,4,6-trimethylbenzyl ring; the dihedral angle Ct-Ru-
C11-N1 is 23.78 whereas the corresponding angle in 3 is 87.08.
This can be attributed to the strong distortion of the carbene
ligand due to the coordination of one N substituent. The
OMe
ˆ
Ru Cseparation in 3 (2.086 ä) is significantly longer than
MeO
Ru
Cl
Ru
N
Cl
N
Cl
that in 5 (2.040 ä).
Cl
N
N
i)
Electrochemical studies of complexes 3 6: The complexes
3
6, which contain pendent or h6-coordinated 2,4,6-tri-
8
methylbenzyl-substituted carbene ligands have been studied
by cyclic voltammetry in order to evaluate the electron
richness of the complexes. The measurements were per-
formed in dichloromethane containing 40 mmol of complex
and nBu4NPF6 (0.026 or 0.05m) as supporting electrolyte. The
corresponding data are compiled in Table 1. It shows that each
carbene complex gives a reversible oxidation process at 100 or
200 mVsÀ1. The nature of the substituent on the second
9
OMe
Scheme 3. i) 1408C, p-xylene.
OMe
These observations show that, on heating, the RuCl2(car-
bene)(p-cymene) complexes loose their arene ligand and that,
Chem. Eur. J. 2003, 9, 2323 2330
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¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2325

P. H. Dixneuf, B. fietinkaya et al.
FULL PAPER
In addition to Grubbs× catalyst,
the ruthenium(ii) allenylidene
complexes
of
the
type
ˆ ˆ ˆ
[RuCl( C C CPh2)(PCy3)(p-
‡
cymene] XÀ have been shown
to be active in ring-closing
metathesis reactions (RCM) of
dienes.[22] The high stability of
complexes 4 6, owing to the
chelate effect, in addition to the
tuneable nature of the R group
on nitrogen provides a new
perspective on the potential of
such complexes as catalyst pre-
cursors. They have been tested
as catalysts in the RCM reac-
tion of diallyltosylamide at
808C, with 2.5 mol% of com-
plex, but showed no activity for
the RCM reaction, as expected
from the absence of an active
Figure 1. Molecular structure of 3, hydrogen atoms have been omitted for clarity. Selected bond lengths [ä] and
À
À
À
À
À
À
angles [8]: Ru1 C13 2.086(3), Ru1 C1 2.206(4), Ru1 C2 2.2114, Ru1 C3 2.220(4), Ru1 C4 2.192(3), Ru1 C5
À
À
À
2.271(4), Ru1 C6 2.260(4), Ru1 Cl1 2.4218(9), Ru1 Cl2 2.4281(9), C13-Ru1-C4 118.90(14), C13-Ru1-C1
119.56(14), C4-Ru1-C1 80.68(14), C13-Ru1-C2 93.48(13), C4-Ru1-C2 68.45(14), C13-Ru1-Cl1 90.99(10), C13-
Ru1-Cl2 89.79(10).
ˆ
carbene moiety (e.g. CHR). To
activate the neutral complexes
4
6, it was necessary to remove
the strongly bound chloride
ligand and introduce an alleny-
lidene ligand. This was done by
treatment of complexes
with 1.2 equivalents of 1,1-di-
phenylprop-2-yn-1-ol and
4 6
1 equivalent of silver triflate at
[23]
room temperature in CH2Cl2
(Scheme 4). The ruthenium al-
lenylidene complexes 10 12
were quantitatively obtained
as dark violet, air-sensitive
solids, but they decomposed
quite rapidly in solution and
were not stable enough for
analysis and 13CNMR spectros-
copy. Their structure is based on
previously known preparations
of
ruthenium allenylidene
complexes from analogous pre-
cursors[22, 23] and on their
1H NMR and IR spectra. Be-
Figure 2. Molecular structure of 5, hydrogen atoms have been omitted for clarity. Selected bond lengths [ä] and
À
À
À
À
À
À
cause of their instability, the
ruthenium allenylidene com-
plexes were in situ generated
angles [8]: Ru1 C11 2.040(3), N1 C11 1.347(3), N2 C11 1.328(3), N1 C10 1.460(3), Ru1 C2 2.280(2), Ru1 C3
À
À
À
À
2.318(3), Ru1 C4 2.191(3), Ru1 C5 2.194(2), Ru1 C6 2.111(2), C10 C6 1.503(4), C1-C6-C10 121.9(3), C5-C6-
C10 117.1(2).
just before the addition of the
diene and the catalytic reac-
nitrogen atom of the carbene ligand, chelated or not, does not
tion.
significantly modify the oxidation potentials. These data show
that the electron richness of the complexes arises more from
the nature of the coordinated arene (C6Me6 > CH2C6H2Me3 >
p-cymene) than from the type of carbene ligand.
Thus, the ruthenium allenylidenes 10 12 were in situ
generated in toluene or chlorobenzene, then dienes 13 were
added, and the solution mixture was heated to 808C. Depend-
ing on the nature of the 1,6-diene (13a d) and the solvent, it
is possible to selectively obtain either a metathesis (14), a
cycloisomerisation (15) or an isomerisation product (16)
(Scheme 5).
Ring-closing metathesis and cycloisomerisation reactions
catalysed by ruthenium allenylidene carbene complexes:
2326
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Chem. Eur. J. 2003, 9, 2323 2330

Carbene Ruthenium(ii) Complexes
2323 2330
Table 1. Cyclic voltammetry data for carbene ruthenium complexes.[a]
With diallyltosylamide 13a the ruthenium allenylidene
complex 10 gave a full conversion after 4 hours at 808Cin
chlorobenzene, and the cycloisomerisation product 15a was
obtained in 94% yield together with the metathesis product
14a in 6% yield (Scheme 5). When the reaction was carried
out in toluene, the activity decreased. After 4 hours only 25%
conversion was observed, and products 14a and 15a were
obtained in 4 and 21% yield, respectively.
Compound
E1/2 (RuIII)/RuII)
DEp [mV]
[V versus SCE]
3
4
5
0.969
0.965
0.979
0.959
1.122[b]
63
75
74
66
111
6
[RuCl2{h1-CN(CH2CH2OMe)CH2CH2N(Me)}-
(p-MeC6H4CHMe2)][8a]
To force complex 10 to produce the metathesis product 14a,
the introduction of a methyl substituent at the double bond
(13e) was necessary (Scheme 6). In this case, after 10 hours in
chlorobenzene at 808C, compound 14a was obtained in 41%
with 9% of different allylic isomerisation products 16a.
[RuCl2{h1-CN(CH2CH2OMe)CH2CH2N(Me)}-
0.958[b]
1.270
122
125
(C6Me6)][8a]
[RuCl2{h1-CN(CH2Ph)CH2CH2N(CH2Ph)}-
(p-MeC6H4CHMe2)][5a]
[a] E vs. SCE; Pt working electrode: 200 mVsÀ1; recorded in CH2Cl2 with
nBu4NPF6 (0.026m) as supporting electrolyte. [b] E vs. SCE; Pt working electrode:
100 mVsÀ1; recorded in CH2Cl2 with nBu4NPF6 (0.05m) as supporting electrolyte.
i)
TsN
+
+
TsN
TsN
TsN
+ TfO-
13e
14a (41 %)
16a (9 %)
i), ii)
Ru
R
Ru
Cl
ˆ ˆ ˆ
Scheme 6. i) [Ru C C CPh2] (10) generated in situ (2.5 mol% Ru),
808C.
N
N
Cl
C
Cl
C
N
N
C
Ph
R
Ph
With 1,6-carbodienes 13b d instead of bisallylamides, only
metathesis products 14b d were obtained (Scheme 5). How-
ever, the reactivity of the complex 10 depends dramatically on
the nature of the solvent. For example, with the diene 13c
bearing two ester substituents, the best conversion was
observed in chlorobenzene contrary to diene 13b and 13d,
which were more easily transformed in toluene (Table 2).
4-5
10: R = CH2CH2OMe
11: R = CH2Mes
+ TfO-
Ru
Ru
Cl
Table 2. Metathesis reaction catalysed by the in situ generated complex 10.
N
i), ii)
N
Cl
C
diene
Conditions[a]
Solvent
Product
Yield (%)[b]
Cl
C
N
N
t [h]
C
Ph
13b
13b
13c
13c
13d
13d
chlorobenzene
toluene
chlorobenzene
toluene
chlorobenzene
toluene
5
6
5
5
5
5
14b
14b
14c
14c
(67)
(94)
(87)
(8)
Ph
O
O
6
12
ꢀ
Scheme 4. i) AgOTf; ii) CH CC(OH)Ph2, C HCl2, RT.
2
14d
(12)
[a] Solvent (2.5 mL), diene 13 (0.5 mmol),
4 (2.5 mol%), AgOTf
ꢀ
(2.5 mol%), HC CCPh2OH (3 mol%), 808C. [b] Determined by gas
chromatography.
i)
+
+
X
X
X
X
With the 1,6-dienes 13a and 13c, the ruthenium precursor
11 selectively gave the cycloisomerisation products 15a and
15c (Scheme 7). Like catalyst 10, catalyst 11 was very sensitive
to the nature of the solvent and catalysis conditions. For
example with the diene 13a, full conversion was observed
after 4 hours at 808Cin toluene compared with 84%
conversion in chlorobenzene. Product 15c was obtained
preferentially in chlorobenzene and after UV activation of
the ruthenium precursor before heating.
The benzimidazolinylidene ruthenium allenylidene 12
was less reactive than the catalyst precursors 10 and 11,
possibly because of its aromatic carbene nature and thus its
weaker electron-releasing character. However, it gave 92% of
16
14
15
13
a: X = TsN; b: X = C(CN)(CO2Et); c: X = C(CO2Et)2; d: X = CCH2OCMe2OCH2
NC
EtO2C
EtO2C
O
TsN
EtO2C
O
15a (94 %)
14b (94 %)
14c (87 %)
14d (12 %)
ˆ ˆ ˆ
Scheme 5. i) [Ru C C CPh2] (10) generated in situ (2.5 mol% Ru),
808C.
Chem. Eur. J. 2003, 9, 2323 2330
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2327

P. H. Dixneuf, B. fietinkaya et al.
FULL PAPER
THF (Na/benzophenone). NMR spectra were recorded on a Bruker
DPX200 or RC300 MHz spectrometer in CDCl 3 or CD2Cl2; chemical shifts
(d) are given in ppm relative to TMS. The IR spectra were recorded in KBr
on a Bruker IFS28 spectrometer.
i)
TsN
TsN
1-methoxyethyl-3-(2,4,6-trimethylbenzyl)-4,5-dihydroimidazolium chlor-
ide (1a): 2,4,6-trimethylbenzyl chloride (1.681 g, 10.1 mmol) was added
slowly to a solution of 1-methoxyethyl-4,5-dihydroimidazole (1.273 g,
10 mmol) in DMF (10 mL) at 258C, and the resulting mixture was stirred
at RT for 6 h. Diethyl ether (15 mL) was added to obtain a white crystalline
solid, which was filtered off. The solid was washed with diethyl ether (3 Â
15 mL), dried under vacuum and gave 2.64 g (89%) of 1a. M.p. ˆ 74
758C; 1H NMR (200.13 MHz, CDCl3): d ˆ 2.15, 2.22 (s, 9H; 3CH3 Mes),
3.20 (s, 3H; OCH3), 3.43, 3.57 (t, 3J(H,H) ˆ 5 Hz, 4H; NCH2CH2N), 3.68 (t,
15a (100 %)
13a
EtO2C
EtO2C
EtO2C
i), ii), iii)
EtO2C
3
3J(H,H) ˆ 3.3 Hz, 2H; CH2CH2O), 3.82 (t, J(H,H) ˆ 3.3 Hz, 2H; CH2O),
4.61 (s, 2H; MesCH2), 6.84 (s, 2H; 2CH Mes), 8.72 (s, 1H; NCHN);
13C NMR (50.33 MHz, CDCl3): d ˆ 19.86, 21.05 (6CH3 Mes), 45.64
(CH2CH2O), 47.20 (CH2O), 48.16, 48.63 (NCH2CH2N), 58.46 (OCH3),
68.12 (CH2Mes), 126.87, 129.74, 138.33 (6Carom Mes), 158.07 (NCHN);
IR(KBr): nÄ ˆ 1651 cmÀ1 (C-N); elemental analysis calcd (%) for
C16H25N2OCl (282.1): C64.76, H 8.43, N 9.44; found: C64.44, H 8.47, N,
9.34.
15c (46 %)
13c
ˆ ˆ ˆ
Scheme 7. i) [Ru C C CPh2] (11) generated in situ (2.5 mol% Ru),
808C; ii) UV, 30 min; iii) 80 8C, chlorobenzene.
cycloisomerisation product 15a from diene 13a after 10 hours
at 808Cin toluene (Scheme 8).
1,3-bis(2,4,6-trimethylbenzyl)-4,5-dihydroimidazolium chloride (1b): Com-
pound 1b was prepared in the same way as 1a from 1-(2,4,6-trimethylben-
zyl)-4,5-dihydroimidazole (2.021 g, 10 mmol) and 2,4,6-trimethylbenzyl
chloride (1.681 g, 10.1 mmol) to give white crystals of 1b. Yield 3.56 g
(96% ); m.p. 295 2968C; 1H NMR (200.13 MHz, CDCl3): d ˆ 2.30, 2.21 (s,
18H; 6CH3 Mes), 3.68 (s, 4H; NCH2CH2N), 4.86 (s, 4H; CH2Mes), 6.82 (s,
4H; CH arom Mes), 9.87 (s, 1H; NCHN); 13C NMR (50.33 MHz, CDCl3):
d ˆ 20.38, 21.25 (6CH3 Mes), 46.64 (2CH2 NCH2CH2N), 47.83 (CH2Mes),
125.84, 130.14, 138.16, 139.31 (6Carom Mes), 158.46 (NCHN); IR(KBr):
nÄ ˆ 1660 cmÀ1 (C-N); elemental analysis calcd (%) for C23H31N2Cl (321.2):
C74.49, H 8.37, N 7.56; found: C73.97, H 8.59, N 7.49.
i)
TsN
TsN
15a (92 %)
13a
ˆ ˆ ˆ
Scheme 8. i) [Ru C C CPh2] (12) generated in situ (2.5 mol% Ru),
808C, toluene, 10 h.
1,3,1',3'tetrakis-(2,4,6-trimethylbenzyl)-[2,2']bis(1,3-imidazolidinylidene)
(2b): The preparation of 2b was done according to Lappert×s procedure.[10]
1H NMR (300.13 MHz, C6D6): d ˆ 2.26 (s, 6H; 2CH3 Mes), 2.56 (s, 12H;
The above results show the most striking evidence that the
nature of the diene and that of the solvent dramatically
influence the nature of the diene×s transformation by a given
catalyst. Indeed with the same precursor 10, diene 13a leads to
94% of 15a, whereas carbodienes 13b and 13c lead to 14b
(67%) and 14c (87%), respectively, under similar conditions.
4CH Mes), 2.75 (s, 4H; NCH2CH2N), 4.62 (s, 4H; CH2Mes), 6.90 (s, 4H;
3
4CH Mes); 13CNMR (75.47 MHz, C 6D6): d ˆ 21.15 (2CH3 Mes), 21.39
(4CH3 Mes), 48.03 (NCH2CH2N), 51.82 (CH2Mes), 129.67, 133.40, 136.36,
138.29 (Carom Mes), 132.18 (NCN).
RuCl2{h1-CN(CH2C6H2Me3-2,4,6)CH2CH2N(CH2CH2OMe)}(C6Me6) (3):
A solution of the electron-rich olefin 2a (286 mg, 0.55 mmol) and the
ruthenium complex [RuCl2(C6Me6)]2 (334 mg, 0.5 mmol) in degassed
toluene (15 mL) was heated in a water bath (95 1008C) for 4 hours. After
the mixture had been cooled to 258C, n-hexane (15 mL) was added, and the
solution was cooled to À158C. The precipitated brown solid was filtered
and recrystallised from dichloromethane/hexane (10:20 mL). Compound 3
was isolated in 78% yield (463 mg).
Conclusion
The present work describes the synthesis and properties of
new chelated, 8-electron arene carbene ruthenium com-
plexes. Compounds 4 6 and 9 are the first examples of
carbene complexes with tethered arene functionality. Steri-
cally demanding CH2Mes substituent(s) at a N atom of the
imidazolidine ring facilitate the displacement of the arene
ligand to yield chelated complexes, a process that was not
observed with an equivalent CH2Ph substituent. Although the
chelated complexes are inactive, their in situ formed allenyl-
idene derivatives are efficient catalysts for the RCM or
cycloisomerisation reactions of 1,6-dienes. Catalytic reactions
proceed with very good efficiency and selectivity under
relatively mild conditions. However, the chemoselectivity of
the reaction dramatically depends on both the diene and
solvent nature.
16
9
10
12
18
8
17
11
7
15
Ru
Cl
13
Cl
N
14
1
2
N
4
3
5
O
6
1H NMR (300.13 MHz, CD2Cl2): d ˆ 1.99 (s, 18H; H-18), 2.20, 2.25 (s, 6H;
H-14 and H-16), 2.34 (s, 3H; H-15), 3.06 (dt, 2J(H,H) ˆ 11.2 Hz, 3J(H,H) ˆ
7.2 Hz, 1H; H-3), 3.15 3.24 (m, 2H; H-3 and H-4), 3.24 (s, 3H; H-6), 3.44
(dt, 2J(H,H) ˆ 11.2 Hz, 3J(H,H) ˆ 7.2 Hz, 1H; H-2), 3.51 3.57 (m, 2H;
H-5), 3.73 (dt, 2J(H,H) ˆ 11.0 Hz, 3J(H,H) ˆ 10.8 Hz, 1H; H-2), 4.23 (d,
2J(H,H) ˆ 13.8 Hz, 1H; H-7), 4.35 (dt, 2J(H,H) ˆ 9.9 Hz, 3J(H,H) ˆ 4.1 Hz,
1H; H-4), 6.10 (d, 3J(H,H) ˆ 13.8 Hz, 1H; H-7), 6.79, 6.81 (s, 2H; H-10 and
H-12); 13CNMR (50.33 MHz, CD 2Cl2): d ˆ 15.93 (6C; C18), 20.88, 21.02
Experimental Section
All reactions were performed under an inert atmosphere of N2 or Ar in
predried glassware by using Schlenk techniques. The solvents were dried by
distillation over the following drying agents and were transferred under N2
or Ar: toluene (Na), CH2Cl2 (P2O5), n-hexane (Na), chlorobenzene (P2O5),
2328
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2003, 9, 2323 2330

Carbene Ruthenium(ii) Complexes
2323 2330
(C14 and C16), 21.54 (C15), 47.76 (C7), 49.73 (C3), 50.06 (C2), 52.03 (C4),
58.83 (C6), 74.73 (C5), 94.39 (6 C17), 129.13, 129.89 (C10 and C12), 130.55
(C8), 137.30, 137.58 (C9 and C13), 140.34 (C11), 210.26 (C1); elemental
analysis calcd (%) for C28H42N2OCl2Ru (594.2): C56.56, H 7.07, N 4.71;
found: C56.29, H 6.93, N 4.49.
48.0 (C10), 63.6 (C1), 75.3 (C2), 106.7, 109.3 (C5 and C8), 120.8, 121.0 (C6
and C7), 129.2, 129.3 (C14 and C17), 130.8 (C15), 136.0 (C12 and C18),
136.7, 136.9 (C4 and C9), 139.2 (C11), 208.7 (C20).
RuCl2[h1-CN{CH2(h6-C6H4-p-OMe)}CH2CH2N(CH2C6H4-p-OMe)] (9): A
suspension of complex 8[13] (0.24 g, 0.5 mmol) in degassed p-xylene (15 mL)
was heated at 1408Cfor 4 h, after the mixture had been cooled at 25 8C, n-
hexane (15 mL) was added, and then the formed orange solid was filtered
and recrystallised from dichloromethane/hexane (10:25 mL) to give 9 as
orange crystals. Yield 0.26 g (86%); m.p. ˆ 252 252.58C; 1H NMR
(300.13 MHz, CDCl3): d ˆ 2.83 (s, 3H; coord. OCH3), 3.07 (s, 3H; free
OCH3), 3.36 (d, 3J(H,H) ˆ 8.3 Hz, 2H; NCH2CH2N), 3.49 (d, 3J(H,H) ˆ
8.3 Hz, 1H; NCH2CH2N), 3.77 (s, 2H; coord. NCH2Ar), 4.74 (s, 2H; free
NCH2Ar), 5.22 (d, 3J(H,H) ˆ 6.63 Hz, 2H; coord. CH Ar), 6.26 (d,
3J(H,H) ˆ 6.63 Hz, 2H; coord. CH Ar), 6.56 (d, 3J(H,H) ˆ 8.71 Hz, 2H;
free CH Ar), 7.19 (d, 3J(H,H) ˆ 8.71 Hz, 2H; free CH Ar); 13CNMR
(75.47 MHz, CDCl3): d ˆ 40.33 (coord. OCH3), 40.67 (free OCH3), 47.87,
51.62 (NCH2CH2N), 49.01 (coord. NCH2Ar), 52.86 (free NCH2Ar), 75.46 (2
ortho-CH coord. Ar), 76.64 (ipso-Ccoord. Ar), 82.35 (2 meta-CH coord.
Ar), 87.36 (para-Ccoord. Ar), 112.47 (2 ortho-CH free Ar), 124.19 (ipso-C
free Ar), 130.39 (meta-CH free Ar), 150.07 (para-Cfree Ar), 201.19
RuCl2[h1-CN{CH2(h6-C6H2Me3-2,4,6)}CH2CH2N(CH2CH2OMe)] (4):
A
solution of the electron-rich olefin 2a (286 mg, 0.55 mmol) and the
ruthenium complex [RuCl2(p-cymene)]2 (306 mg, 0.5 mmol) in degassed
toluene (15 mL) was heated in a water bath (95 1008C) for 4 h to give 4 in
84% yield (363 mg) after extraction and crystallisation as for complex 3.
1H NMR (200.13 MHz, CDCl3): d ˆ 2.05 (s, 6H; 2CH3 Mes), 2.19 (s, 3H;
CH3 Mes), 3.18 (s, 3H; OCH3), 3.42 (d, 3J(H,H) ˆ 4.2 Hz, 2H;
3
NCH2CH2N), 3.70 (d, J(H,H) ˆ 4.2 Hz, 2H; NCH2CH2N), 3.64 3.97 (m,
4H; NCH CH2O), 4.05 (s, 2H; NCH2Mes), 5.34 (s, 2H; CH Mes); 13CNMR
2
(50.33 MHz, CDCl3): d ˆ 16.82 (2CH3 Mes), 17.36 (CH3 Mes), 47.05
(NCH2CH2NC), 48.23 (NCH2Mes), 49.23 (CH2NCH2CH2), 51.98
(CH2CH2O), 58.57 (OCH3), 74.67 (CH2O), 88.47 (2ortho-CMes), 93.89
ˆ
(para CMes), 98.89 (2CH Mes), 100.37 ( ipso-CMes), 200.14 (Ru C); FAB
m/z: 432.03 [4] ; elemental analysis calcd (%) for C16H24N2OCl2Ru (432.0):
‡
C44.44, H 5.55, N 6.48; found: C44.23, H 5.49, N 6.22.
ˆ
(Ru C); elemental analysis calcd (%) for C19H22N2O2Cl2Ru (482.0): C
47.30, H 4.56, N 5.81; found: C47.16, H 4.35, N 5.69.
Transformation 3 ! 4: Complex 3 (594 mg, 1 mmol) in xylene (15 mL) was
heated at 1408Cfor 3h to give 4 in 90% yield (389 mg) after extraction and
crystallisation as above.
[RuCl{h1-CN[CH2(h6-C6H2Me3-2,4,6)]CH2CH2N(CH2CH2O-
ˆ ˆ ˆ
RuCl2[h1-CN{CH2(h6-C6H2Me3-2,4,6)}CH2CH2N(CH2C6H2Me3-2,4,6)] (5):
A solution of the electron-rich olefin 2b (360 mg, 0.55 mmol) and the
ruthenium complex [RuCl2(p-cymene)]2 (306 mg, 0.5 mmol) in degassed
toluene (15 mL) was heated in a water bath (95 1008C) for 4 h to give 5 in
91% yield (460 mg) after extraction and crystallisation as above. 1H NMR
(200.13 MHz, CDCl3): d ˆ 2.11 (s, 6H; 2 coord. CH3 Mes), 2.16 (s, 3H; free
CH3 Mes), 2.19 (s, 9H; 1 coord. CH3 Mes and 2 free CH3 Mes), 3.28 (d,
2J(H,H) ˆ 9.9 Hz, 2H; NCH2), 3.64 (d, 2J(H,H) ˆ 9.0 Hz, 2H; NCH2), 4.05
(s, 2H; coord. NCH2Mes), 5.03 (s, 2H; free NCH2Mes), 5.34 (s, 2H; coord.
CH Mes), 6.71 (s, 2H; free CH Mes); 13C NMR (50.33 MHz, CDCl3): d ˆ
16.94 (2 coord. CH3 Mes), 17.47 (coord. CH3 Mes), 20.43 (2 free CH3 Mes),
20.90 (free CH3 Mes), 46.88 (CH2NCH2 coord. Mes), 47.08 (NCH2 coord.
Mes), 47.66 (NCH2 free Mes), 48.97 (CH2NCH2 free Mes), 89.96 (2 ortho-C
coord. Mes), 92.41 (para-Ccoord. Mes), 97.45 (2CH coord. Mes), 103.03
(ipso-Ccoord. Mes), 129.18 (2CH free Mes), 129.33 ( ipso-Cfree Mes),
C C CPh2)][TfO] (10): Complex 4 (95 mg, 0.22 mmol) and silver triflate
(57 mg, 0.22 mmol) in degassed CH2Cl2 (5 mL) were stirred for 15 minutes
ꢀ
at room temperature. Then, HC CCPh2OH (48 mg, 0.23 mmol) was added,
and the reaction mixture was stirred at room temperature for additional
15 min. The purple solution was filtrated with a cannula paper filter, and
CH2Cl2 was evaporated off under vacuum. Complete conversion into
complex 10 was observed by 1H NMR spectroscopy based on the
coordinated mesityl protons chemical shifts. 1H NMR (200.13 MHz,
CD2Cl2): d ˆ 2.09 (s, 6H; 2CH3 Mes), 2.24 (s, 3H; CH3 Mes), 3.28 4.10
(m, 8H; NCH2CH2N and NCH2CH2O), 4.20 4.35 (m, 2H; NCH2Mes),
6.27 (s, 1H; CH Mes), 6.32 (s, 1H; CH Mes), 7.50 (t, 3J(H,H) ˆ 7.5 Hz, 4H;
3
3
Ph), 7.77 (t, J(H,H) ˆ 7.5 Hz, 2H; Ph), 7.91 (t, J(H,H) ˆ 7.5 Hz, 4H; Ph);
IR (KBr): nÄ ˆ 1965 cmÀ1 (Ru C C C).
ˆ ˆ ˆ
[RuCl{h1-CN[CH2(h6-C6H2Me3-2,4,6)]CH2CH2N(CH2C6H2Me3-2,4,6)}-
ˆ ˆ ˆ
( C C CPh2)][TfO] (11): Complex 5 (111 mg, 0.22 mmol) and silver
ˆ
136.99 (para-Cfree Mes), 138.26 (2 ortho-Cfree Mes), 199.95 (Ru C);
FAB m/z: 506.08 [5] ; elemental analysis calcd (%) for C23H30N2Cl2Ru
triflate (57 mg, 0.22 mmol) in degassed CH2Cl2 (5 mL) were stirred for
‡
ꢀ
15 minutes at room temperature. Then HC CCPh2OH (48 mg, 0.23 mmol)
(506.1): C54.54, H 5.93, N 4.71; found: C54.32, H 5.83, N 5.30.
was added, and the reaction mixture was stirred at room temperature for
additional 15 min. The purple solution was filtrated with a cannula paper
filter, and CH2Cl2 was evaporated off under vacuum. Complete conversion
into complex 11 was observed by 1H NMR spectroscopy based on the
coordinated mesityl protons chemical shifts. 1H NMR (200.13 MHz,
CD2Cl2): d ˆ 2.09 (s, 6H; 2CH3 Mes), 2.17 (s, 3H; CH3 Mes), 2.19 (s, 9H;
RuCl2[h1-CN{CH2(h6-C6H2Me3-2,4,6)}C6H4N(CH2CH2OMe)] (6): A sus-
pension of 1-(methoxyethyl)-3-(2,4,6-trimethylbenzyl)benzimidazolium
chloride 7 (0.72 g, 2.10 mmol), Cs2CO3 (0.70 g, 2.14 mmol) and [RuCl2(p-
cymene)]2 (0.50 g, 0.82 mmol) was heated under reflux in degassed toluene
(20 mL) for 7 h. The reaction mixture was then filtered while hot, and the
volume was reduced to about 10 mL before addition of n-hexane (15 mL).
The precipitate formed was crystallised from CH2Cl2/hexane (5:15 mL) to
give 0.50 g (78%) of brown crystals.
3CH Mes), 3.21 (d, 3J(H,H) ˆ 10.2 Hz, 2H; NCH2), 3.74 (d, 3J(H,H) ˆ
3
9.7 Hz, 2H; NCH2), 4.24 (d, 2J(H,H) ˆ 18.2 Hz; 2H, coord. NCH2Mes),
5.80 (d, 2J(H,H) ˆ 14.0 Hz, 1H; free NCH2Mes), 5.88 (d, 2J(H,H) ˆ
14.0 Hz, 1H; free NCH2Mes), 6.26 (s, 1H; coord. CH Mes), 6.34 (s, 1H;
coord. CH Mes), 6.72 (s, 2H; free CH Mes), 7.47 (t, 3J(H,H) ˆ 7.5 Hz, 4H;
13
3
3
12
14
Ph), 7.74 (t, J(H,H) ˆ 7.5 Hz, 2H; Ph), 7.95 (t, J(H,H) ˆ 7.5 Hz, 4H; Ph);
11
19
15
IR (KBr): nÄ ˆ 1969 cmÀ1 (Ru C C C).
ˆ ˆ ˆ
16
10
18
17
Representative procedure for catalysis by using an in situ prepared
ruthenium allenylidene precursor 10 12: Ruthenium precursor
Ru
Cl
N
4 6
Cl
20
9
8
(1.25 Â 10À2 mmol, 2.5 mol%) and silver triflate (3.2 mg, 1.25 Â
10À2 mmol, 2.5 mol%) were introduced into a Schlenk tube under argon.
The Schlenk tube was then purged three times, and degassed solvent
(toluene or chlorobenzene, 2.5 mL) was added. The reaction mixture was
then stirred at room temperature for 15 minutes before the addition of
N
3
4
7
5
2
6
O
propargylic alcohol HC CCPh2OH (2.7 mg, 1.3 Â 10À2 mmol, 2.6 mol%).
ꢀ
1
The reaction was stirred at room temperature for an additional 15 minutes.
Diene (0.5 mmol) was then added to the purple solution. The reaction
mixture was heated at 808C. After the mixture had been cooled to room
temperature, the solvent was reduced under vacuum. The conversion was
1H NMR (300.13 MHz, CDCl3): d ˆ 1.62 (s, 3H; H-16), 2.05, 2.16 (s, 6H;
3
3
H-13 and H-19), 3.69 (dd, J(H,H) ˆ 9.5 Hz, J(H,H) ˆ 10.0 Hz, 1H; H-2),
4.03 (s, 3H; H-1), 4.31 4.44 (m, 2H; H-2 and H-3), 4.93 (d, 2J(H,H) ˆ
1
determined directly on the crude product by H NMR spectroscopy.
2
15.2 Hz, 1H; H-10), 5.82 (d, J(H,H) ˆ 15.2 Hz, 1H; H-10), 6.18 6.26 (m,
Representative procedure for catalysis by using an in situ prepared
ruthenium allenylidene precursor and UV activation: Ruthenium pre-
cursor 5 (6.3 mg, 1.25 Â 10À2 mmol, 2.5 mol%) and silver triflate (3.2 mg,
1.25 Â 10À2 mmol, 2.5 mol%) were introduced into a Schlenk tube under
1H; H-3), 6.33, 7.18 (d, 3J(H,H) ˆ 7.7 Hz, 2H; H5 and H8), 6.53, 6.73 (s, 2H;
H14 and H17), 6.75, 7.02 (d, 3J(H,H) ˆ 7.7 Hz, 2H; H-6 and H-7); 13CNMR
(50.33 MHz, CDCl3): d ˆ 19.8 (C16), 21.1, 21.5 (C13 and C19), 46.2 (C3),
Chem. Eur. J. 2003, 9, 2323 2330
www.chemeurj.org
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2329

P. H. Dixneuf, B. fietinkaya et al.
FULL PAPER
¬
argon. The Schlenk tube was then purged three times, and degassed
chlorobenzene (2.5 mL) was added. The reaction mixture was then stirred
at room temperature for 15 minutes before the addition of propargylic
[9] B. fietinkaya, S. Demir, I. ÷zdemir, L. Toupet, D. Semeril, C.
Bruneau, P. H. Dixneuf, New J. Chem. 2001, 25, 519 521.
[10] E. fietinkaya, P. H. Hitchcock, H. A. Jasim, M. F. Lappert, K.
Spyropoulos, J. Chem. Soc. Perkin Trans. 1 1992, 561 567.
[11] a) J. C. C. Chen, I. J. B. Lin, Organometallics 2000, 19, 5113 5121;
b) D. S. McGuinness, K. J. Cavell, Organometallics 2000, 19, 741 748;
c) E. Peris, J. A. Loch, J. Mata, R. H. Crabtree, Chem. Commun. 2001,
201 202.
alcohol HC CCPh2OH (2.7 mg, 1.3 Â 10À2 mmol, 2.6 mol%). The reaction
ꢀ
mixture was stirred at room temperature for an additional 15 minutes and
irradiated with UV for 30 minutes. Then diene 13c (0.5 mmol) was added
to the solution, and the reaction mixture was heated at 808Cfor 5 h. After
the mixture had been cooled to room temperature, the solvent was reduced
under vacuum, and the conversion was calculated directly on the crude
¬
[12] D. Semeril, C. Bruneau, P. H. Dixneuf, Adv. Synth. Catal. 2002, 344,
1
product by H NMR spectroscopy.
585 595.
[13] I. ÷zdemir, B. Yigit, B. fietinkaya, D. ‹lk¸, M. N. Tahir, C. Arici, J.
Organomet. Chem. 2001, 633, 27 32.
[14] Crystal data for compound 3: C28H42N2ORuCl2,
C
HCl2, M ˆ
2
Acknowledgement
679.53 gmolÀ1, orange-brown crystal with dimensions 0.32 Â 0.30 Â
0.15 mm, monoclinic P21/c, at 95 K: a ˆ 9.5630(1), b ˆ 13.1030(1),
c ˆ 24.2780(3) ä, b ˆ 90.945(4)8, Vˆ 3041.72(5) ä3, Z ˆ 4, 1 ˆ
1.484 MgmÀ3, m ˆ 8.92 cmÀ1, l ˆ 0.71073 ä. X-ray diffraction data for
this structure and 5 were collected by using a NONIUS Kappa CCD
with graphite monochromatised MoKa radiation. The cell parameters
were obtained with Denzo and ScaIepack[16] with 10 frames (psi
rotation: 18 per frame). The data collection[17] (2qmax ˆ 54.08) gave
43909 integrated reflections. The data reduction with Denzo and
ScaIepack[16] lead to 6932 independent reflections (6352 with I >
2s(I)). The structure was solved with SIR-97[18], which reveals all
the non-hydrogen atoms of the compound and a dichloromethane
molecule. After anisotropic refinement, many hydrogen atoms were
found with a Fourier difference. The whole structure was refined with
SHELXL-97[19] by the full-matrix least-squares techniques (335
variables and 6352 observations with I > 2s(I), R ˆ 0.049, wR ˆ 0.122
and residual D1 < 1.05 eäÀ3). Atomic scattering factors came from the
International Tables for X-ray Crysta1lography.[20] Ortep views were
realised with PLATON98.[21] See also: CCDC-195933.
The authors are grateful to the CNRS and T¸bitak and to the European
Union COST program Action D17 (003) for support.
[1] a) B. fietinkaya, P. H. Dixneuf, M. F. Lappert, J. Chem. Soc. Dalton
Trans. 1974, 1827 1833; b) M. F. Lappert, J. Organomet. Chem. 1988,
358, 185 213.
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[15] Crystal data for compound 5: C23H30N2RuCI2, M ˆ 506.46 gmolÀ1
,
orange-brown crystal with dimensions 0.28 Â 0.22 Â 0.14 mm, mono-
clinic, P21/c, at 293 K, a ˆ 8.0230(1), b ˆ 8.2340(1), c ˆ 33.3210(5) ä,
b ˆ 90.401(5)8, Vˆ 2201.18(5) ä3, Z ˆ 4, 1 ˆ 1.580 MgmÀ3
,
m ˆ
9.66 cmÀ1
,
l ˆ 0.71073 ä. X-ray diffraction (2qmax ˆ 54.08) gives
14669 integrated reflections, the data reduction leads to 4783
independent reflections (4238 with I > 2s(I)). Refinement 254 varia-
bles and 4783 observations with I > 2s(I) gives R ˆ 0.038, wR ˆ 0.095
and residual D1 < 0.48 eäÀ3. See also: CCDC-159033.
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Received: October 28, 2002 [F4533]
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