Synthesis and characterization of non-chelating ruthenium-indenylidene olefin metathesis catalysts derived from substituted 1,1-diphenyl-2-propyn-1-ols

Article abstract of DOI:10.1039/c4nj02034k

We report on the synthesis and characterization of the first generation of modified non-chelating indenylidene ruthenium catalysts denoted as RuCl₂(4-methyl-3-(o-tolyl)-1-indenylidene)(PCy₃)₂ 5a, RuCl₂(3-(p-fluorophenyl)-1-indenylidene)(PCy₃)₂ 5b, RuCl₂(3-(2,6-xylyl)-1-indenylidene)(PCy₃)₂ 5c and RuCl₂(3-(1-naphthyl)-1-indenylidene)(PCy₃)₂ 5d. The obtained complexes of 5a-d were characterized by means of NMR spectroscopy and elemental analysis. Moreover the structures of 5a-d were confirmed by single-crystal X-ray diffraction and compared with the standard ruthenium indenylidene complex 3 and the chelating benzylidene complex 2. Additionally, the catalytic performances of the obtained complexes 5a-d were evaluated in various metathesis reactions demonstrating that the ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP) reactions revealed a similar catalytic activity in comparison with the reference indenylidene catalyst 3.

Full text of DOI:10.1039/c4nj02034k

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Synthesis and characterization of non-chelating
ruthenium–indenylidene olefin metathesis catalysts
derived from substituted 1,1-diphenyl-2-propyn-1-ols†
Cite this:DOI: 10.1039/c4nj02034k
Baoyi Yu,a Yu Xie,bc Fatma B. Hamad,d Karen Leus,a Alex A. Lyapkov,e
Kristof Van Heckea and Francis Verpoort*abce
We report on the synthesis and characterization of the first generation of modified non-chelating
indenylidene ruthenium catalysts denoted as RuCl2(4-methyl-3-(o-tolyl)-1-indenylidene)(PCy3)2 5a,
RuCl2(3-(p-fluorophenyl)-1-indenylidene)(PCy3)2 5b, RuCl2(3-(2,6-xylyl)-1-indenylidene)(PCy3)2 5c and
RuCl2(3-(1-naphthyl)-1-indenylidene)(PCy3)2 5d. The obtained complexes of 5a–d were characterized by
means of NMR spectroscopy and elemental analysis. Moreover the structures of 5a–d were confirmed
by single-crystal X-ray diffraction and compared with the standard ruthenium indenylidene complex 3
and the chelating benzylidene complex 2. Additionally, the catalytic performances of the obtained
complexes 5a–d were evaluated in various metathesis reactions demonstrating that the ring-closing
metathesis (RCM) and ring-opening metathesis polymerization (ROMP) reactions revealed a similar
catalytic activity in comparison with the reference indenylidene catalyst 3.
Received (in Porto Alegre, Brazil)
14th November 2014,
Accepted 16th December 2014
DOI: 10.1039/c4nj02034k
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Introduction
The successful development of versatile catalysts enabled olefin
metathesis to become a powerful synthetic tool in organic and
polymer chemistry.1 An important contribution in the area of
the ruthenium based olefin metathesis catalysts was made by
Grubbs group through the introduction of the ruthenium
benzylidene catalyst 1a (Fig. 1).2 Based on complex 1a, various
catalysts bearing different types of ligands were made to enhance
the catalytic performance.3 The so-called ‘‘second generation
Grubbs catalyst’’ 1b was synthesized by replacing one of the
Fig. 1 Ruthenium-based olefin metathesis catalysts.
tricyclohexylphosphine (PCy3) ligands by the N-heterocyclic
carbene (NHC) ligand, which resulted in a more stable complex
in comparison to the ‘‘first generation Grubbs catalyst’’ 1a.4
Further on, various modifications based on NHC ligands have
been reported, using symmetric, asymmetric, or highly steric
NHCs.3a–c,5 The introduction of other ligands to replace the
second PCy3 ligand gave rise to several groups of complexes with
different catalytic performance. Some of these materials showed a
very high initial activity, e.g. including pyridine,6 while others first
needed to be activated, e.g. with Schiff bases.7 Modification of the
alkylidene part, on the other hand, resulted into different families
of ruthenium based catalysts, such as the Grubbs–Hoveyda 2,8
indenylidene,9 allenylidene,10 vinylidene,11 and thiophenylidene
catalysts.12
a Department of Inorganic and Physical Chemistry, Ghent University,
Krijgslaan 281-S3, 9000, Ghent, Belgium. E-mail: Francis.Verpoort@UGent.be;
Fax: +32-9-264-4183
b Laboratory of Organometallics, Catalysis and Ordered Materials,
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,
Center for Chemical and Material Engineering, Wuhan University of Technology,
Wuhan 430070, P. R. China
c Department of Applied Chemistry, Faculty of Sciences,
Wuhan University of Technology, Wuhan 430070, P. R. China
d Dar es Salaam University College of Education, Faculty of Science,
Department of Chemistry, P.O. Box 2329, Dar es Salaam, Tanzania
e National Research Tomsk Polytechnic University, Tomsk, Russian Federation
† Electronic supplementary information (ESI) available: Detailed synthesis pro-
cedure of the propargylic alcohols 6a–d, 8; X-ray data of 6a and 2; Plausible
mechanism for ruthenium indenyldene catalysts synthesis process as well as 1H,
13C and 31P NMR spectra of obtained compounds are included here. CCDC
986932–986934 and 1005472–1005476. For ESI and crystallographic data in CIF or
other electronic format see DOI: 10.1039/c4nj02034k
Complexes 1 and 2 are widely applied because of their stability,
functional group compatibility and high catalytic efficiency.1b,c
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The systematic exploration of the electronic effects of the alkyl- alcohol with RuCl2(PPh3)3.9a Afterward, the groups of Nolan
idene group on the catalytic performance revealed that electron and Fu¨rstner reported the proper structure,9b,10 while later on,
withdrawing para-substituents not only withdraw electron density Fu¨rstner’s group revealed the detailed synthesis procedure and
from the aromatic ring but also from the RuQC center, which characterization of 3.9c Nevertheless, the synthesis of complex 3
resulted in a fast initiating catalyst.13
was not always straightforward and in many cases the complex
The direct treatment of propargylic alcohols with RuCl2(PPh3)3 having four doublet peaks [(m-Cl)3-bridged Ru2(allenylidene)
gave rise to alkenylidene14 (vinylidene,15 allenylidene10,16 and complex] in the 31P NMR spectrum was obtained. In 2007, the
indenylidene9a,17) ruthenium complexes. The latter method is a group of Schanz reported on the involved mechanism, which
much more convenient way to obtain the ruthenium catalysts3d demonstrated that an acid catalyst is required to obtain the
compared with their benzylidene analogue 1a.2 However, these complex.17d
vinylidene and allenylidene catalysts exhibit a much lower cata-
In this work, series of 1,1-diphenyl-2-propyn-1-ol (6a, 6b,26
lytic performance3d in comparison to the benchmark catalysts 6c and 6d) derivates were prepared for the synthesis of new
13a,4d and 2.8 On the contrary, ruthenium indenylidene catalysts ruthenium indenylidene catalysts (see ESI† for the detailed
show an increased stability and comparable, or sometimes a synthesis procedure of each ligand and crystal data of 6a).
higher, catalytic activity in metathesis reactions in comparison
The complex 7a was prepared according to the earlier
to the ruthenium benzylidene complexes 1a and 2.9c,18 Aiming at reported synthesis procedure using an acid catalyzed reaction
improving the properties of the latter catalysts, a number of of propargylic alcohol with RuCl2(PPh3)3 (Scheme 1A).27 Hence,
modifications have been carried out starting from the ruthenium a 1.3 eq. of 6a was allowed to react with the RuCl2(PPh3)3 in
indenylidene complex 3. These modifications include the intro- dioxane at 90 1C in the presence of HCl. During the reaction,
duction of NHCs,19 and substitution of PCy3 by other ligands such aliquots were taken out and were analyzed by means of 31P
as phosphines,20 pyridine21 and Schiff bases.22
NMR spectroscopy. After 10 minutes of reaction, the RuCl2(PPh3)3
In addition, a variety of bidentate catalysts bearing (k2O,C)- was completely consumed while a new phosphine signal at
iso-propoxy-indenylidene moieties (4a–c) have been reported to 29.3 ppm appeared, which was assigned to the PPh3 coordi-
date.23 For instance, Bruneau et al. reported on the chelating nated complex 7a in addition to that of free PPh3 (À5.4 ppm).
complex 4a, which showed a rather good thermal stability. Additional structural information of compound 7a was obtained
Nevertheless, it showed a poor initiation for olefin metathesis by single crystal X-ray diffraction (see the section ‘‘single crystal
at low temperature. Ring-closing metathesis (RCM) of diethyl X-ray diffraction analysis’’).
diallylmalonate (DEDAM), using compound 4a, still reached
In a next step, complex 7a was applied as a precursor for the
comparable yields as obtained for the complexes 2 and 3, synthesis of the 1st generation modified ruthenium indenylidene
although a longer reaction time was needed.23a Nearly simulta- complex 5a (Scheme 1A) by treatment of 7a with 3 eq. PCy3 in
neous, Schrodi et al. reported on an in situ generated methoxy- CH2Cl2 at room temperature. The purification was carried out to
chelating ruthenium indenylidene, which showed a comparable obtain compound 5a in a high yield (490%) as a red brown
activity as Grubbs–Hoveyda 2 for the RCM of DEDAM.24 In another compound by simply washing with iso-propanol. The 1H NMR
paper of the same group, a process was described where 2 was spectrum of 5a was measured showing a characteristic peak of the
decomposed, induced by ethylene, yielding RCM-inactive species. indenylidene unit, a typical doublet peak for H7 (Scheme 1B) at
The decomposed compound could be reactivated by a treatment d = 8.54 ppm while the 13C NMR spectrum exhibited a triplet at
with 1-(3,5-di-iso-propoxyphenyl)-1-phenyl-2-propyn-1-ol.25
d = 296.0 ppm with a 2JP,C of 7.6 Hz for the C1 (see Fig. S11 and S12
The relatively low cost and easy synthesis strategy and the in the ESI†).
excellent catalytic performance in olefin metathesis of the
Complexes 5b–d were synthesized in a similar manner as 5a.
indenylidene type catalysts9c have attracted our attention. How- Nevertheless, a slower conversion of 6b–d towards complexes
ever, the chelating modified ruthenium indenylidene catalysts 7b–d was observed in comparison to the formation of complex 7a.
showed a lower initial catalytic activity in comparison with the
reference non-chelating complex 3.23,24 Therefore, in this
paper, we report on the synthesis, characterization and catalytic
performance of non-chelating modified ruthenium indenylidene
complexes, bearing different substituents on the indenylidene
moiety. The general structure of these complexes is represented
in 5 (Fig. 1).
Results and discussion
Synthesis and characterization of the catalysts
The first ruthenium indenylidene complex 3 was discovered
Scheme 1 (A) General applied synthesis strategy for the synthesis of func-
incidentally by Hill’s group on their attempt to synthesize the
tionalized non-chelating indenylidene catalysts. (B) Numbering scheme of the
ruthenium allenylidene complex from the reaction of propargylic indenylidene atoms.
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Table 1 Typical NMR spectra peaks (1H for H7, 13C for C1, 31P) for 3, 5a–d
1H NMR (H7)
13C NMR (C1)
31P NMR
Solvent
3a
8.67
8.54
8.67
8.71
8.70
293.9
296.0
293.3
295.6
294.9
32.6
31.7
32.3
32.9
32.1
CD2Cl2
CDCl3
CDCl3
CDCl3
CDCl3
5a
5b
5c
5d
a
Data according to ref. 9c.
The 31P NMR spectra of 7b and 7d exhibited single signals at
28.3 ppm and 28.8 ppm, respectively, while the 31P NMR signal of
7c exhibited a peak at 29.7 ppm. Further on, complexes 5b–d were
synthesized and isolated in high purity by using column chromato-
graphy with a yield of 60%, 76% and 43%, respectively. All the
synthesized complexes 5a–d were analyzed by 1H, 13C{1H}, 31P{1H}
(see Fig. S11–S23 in the ESI†), H{1H} COSY, H{13C} HSQC and
HMBC NMR spectra. Proton and carbon signals on the indenylidene
moieties were assigned according the obtained spectral data (the
exact number labeling for each atom is indicated on the molecular
structure in the 1H NMR and 13C NMR spectra figures in the ESI†).
The characteristic chemical shifts of compounds 5a–d were com-
pared with complex 3 and are summarized in Table 1. Additionally,
the structural configurations of 5a–d were confirmed by single-
crystal X-ray diffraction (see the section ‘‘single crystal X-ray
diffraction analysis’’).
1
1
Fig. 2 Molecular structure of compound 7a, showing the atom labeling
scheme of the heteroatoms and carbon atom C1. Hydrogen atoms and the
disorder of two of the phenyl groups in PPh3 are omitted for clarity.
in an NMR tube and submitted to single crystal X-ray analysis.
The compound 7a crystallized in the centro-symmetric triclinic
%
space group P1. The asymmetric unit of the structure consists
of one RuCl2(4-methyl-3-(o-tolyl)-1-indenylidene)(PPh3)2 mole-
cule (Fig. 2), two of the six phenyl groups in PPh3 are disordered
over two positions. Complex 7a features a slightly distorted
square-pyramidal geometry around the ruthenium atom, with
the indenylidene moiety in the axial position. The basal square
plane is defined by the two phosphorus atoms of the PPh3
ligands and two chlorides, positioned in trans configuration. The
ruthenium atom is displaced from the square plane towards
the indenylidene ligand by 0.3688(4) Å. The Ru–Cl bond lengths
are 2.355(2) and 2.374(2) Å, and the Ru–P bond lengths are
2.382(2) and 2.399(1) Å. The RuQC bond length is 1.852(6) Å,
and the Cl–Ru–Cl and P–Ru–P angles are 155.26(5) and
168.35(5)1, respectively. The angle between the RuP2 and RuCl2
least-squares planes is 89.2(2)1. The indenylidene ligand is
torsioned with respect to the trans chlorides (Cl1–Ru1–C1–C2
torsion angle of 151.3(4)1). A potential intramolecular hydrogen
bond is observed between the indenylidene ligand and one of
the chlorides: C7–H7Á Á ÁCl1 (CÁ Á ÁCl distance of 3.471(6) Å).
Compound 5a crystallized in the centro-symmetric monoclinic
space group P21/c. The asymmetric unit of the structure consists
of one RuCl2(4-methyl-3-(o-tolyl)-1-indenylidene)(PCy3)2 molecule
and one CH2Cl2 solvent molecule. The o-tolyl moiety is found
disordered over two positions, rotated about 1621 with respect to
each other (Fig. 3). Analogous to 7a, complex 5a features a slightly
distorted square-pyramidal geometry around the ruthenium
atom, with the indenylidene moiety in the axial position. The
ruthenium atom is displaced from the basal square plane towards
the indenylidene ligand by 0.3699(3) Å. The Ru–Cl bond lengths
are 2.379(1) and 2.401(2) Å, and the Ru–P bond lengths are
2.415(1) and 2.429(1) Å. The RuQC bond for 5a (1.864(4) Å) is a
Encouraged by the success in the synthesis of 5a–d, another
ligand, denoted as 1,1-bis(3,5-dichlorophenyl)-2-propyn-1-ol 8 was
synthesized, bearing a more electron-withdrawing substituent.
Following the general reaction procedure outlined in Scheme 1
for the synthesis of 7a–d, the propargylic alcohol 8 was added to
react with the RuCl2(PPh3)3 and was stirred at 90 1C. The 31P NMR
spectrum of the crude reaction mixture in CDCl3 revealed four clear
doublet peaks at 49.8 (d, 2JP–P = 37.1 Hz), 46.8 (d, 2JP–P = 37.1 Hz),
2
2
41.2 (d, JP–P = 25.3 Hz) and 39.1 (d, JP–P = 25.3 Hz) ppm besides
few low-intensity unidentified peaks. This 31P NMR spectrum signal
pattern is similar to the one reported for the well-defined
(PPh3)2ClRu(m-Cl)3Ru(PPh3)2(QCQCQCPh2) complex in which
2
2
four doublets peaks at 51.4 (d, JP–P = 37.8 Hz), 48.9 (d, JP–P
=
37.8 Hz), 40.8 (d, 2JP–P = 26.6 Hz) and 37.0 (d, 2JP–P = 26.6 Hz) ppm
were observed.17d Furthermore, Schrodi et al. obtained an identical
¨
pattern by using the ligands 1-(3,5-dimethoxyphenyl)-2-propyn-1-ol
and 1-(3,5-dimethoxyphenyl)-1-methyl-2-propyn-1-ol, suggesting the
in situ formation of (m-Cl)3-bridged Ru2(allenylidene) complexes.24b
Based on these previous observation in literature, we assume that
the propargylic alcohol 8 only leads to the formation of a (m-Cl)3-
bridged Ru2(allenylidene) complex, and the further reorganization
to form an indenylidene is prohibited by the strong electron
withdrawing substituents. A plausible reaction mechanism based
on current work and earlier literature reports is presented in the
supporting information to explain the formation of the indenylidene
complexes.
Single crystal X-ray diffraction analysis
Crystals of complexes 5a and 7a were obtained by slow diffusion bit longer than its PPh3 analogue 7a (1.852(6) Å). The Cl–Ru–Cl
of iso-propanol, layered on a solution of the complex in CH2Cl2 and P–Ru–P angles are 163.33(4) and 161.27(4)1, respectively.
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Fig. 4 Molecular structures of compounds 3 and 5b–d, showing atom
labeling scheme of the hetero-atoms and carbon atom C1. Hydrogen atoms
are omitted for clarity. For 3, 5c and 5d, the disorder of the 3-phenyl-1-
indenylidene, 3-(2,6-xylyl)-1-indenylidene and 3-(1-naphthyl)-1-indenylidene
moieties are shown in yellow.
Fig. 3 Molecular structure of compound 5a, showing the atom labeling
scheme of the heteroatoms and carbon atom C1. The disorder of the
o-tolyl moiety is shown in yellow. Hydrogen atoms and the CH2Cl2 solvent
molecule are omitted for clarity.
in various benchmark metathesis reactions.21,30 These include the
RCM of diethyl 2,2-diallylmalonate 11, the RCM of diethyl 2-allyl-
2-(2-methylallyl)malonate 13 and the ring-opening metathesis
polymerization (ROMP) of cis,cis-cycloocta-1,5-diene (COD).
The angle between the RuP2 and RuCl2 least-squares planes is
87.8(2)1. The indenylidene ligand is torsioned with respect to
the trans chlorides (Cl1–Ru1–C1–C2 torsion angle of À159.4(4)1).
Potential intramolecular hydrogen bonds are observed between
the indenylidene ligand and the chlorides: C2–H2ÁÁÁCl2 (CÁÁÁCl
distance of 3.200(5) Å) and C7–H7ÁÁÁCl1 (CÁÁÁCl distance of
3.287(5) Å).
(1)
Crystals of compounds 3 and 5b–d were obtained by fast
evaporation of a solution of the complex in CH2Cl2 on a glass slide
and submitted to single crystal X-ray analysis. All compounds 3,
In Fig. 5, the catalytic performance of the complexes 5a–d
and 3 for the RCM of substrate 11 (eqn (1)) is depicted. The
catalytic tests were carried out in CDCl3 at 20 1C using a catalyst
loading of 0.5 mol%. As can be seen from this figure, all the
synthesized complexes 5a–d show a similar activity in compari-
son to the standard complex 3. A conversion of approximately
90% was observed after a reaction time of 35 minutes.
Besides the RCM reaction, the performance of catalysts 5a–d
in ROMP of COD (eqn (2)) is compared to the catalyst 3 (Fig. 6).
Also, for this reaction, no significant differences were observed
between the catalysts 5a–d and 3. A conversion of approxi-
mately 93% was noted after 180 minutes of reaction, which is in
accordance to the benchmark complex 3.
In a last catalytic study, the complexes 5a–d were examined
for the RCM of the partially steric hindered substrate 13 (eqn (3))
at 35 1C using a catalyst loading of 1 mol% (Fig. 7). Never-
theless, despite the more steric hindered substrate was used,
all the catalysts exhibited again a similar kinetic profile and
efficiency.
%
5b–d crystallized in the centro-symmetric trigonal space group R3
with 18 ruthenium based molecules in one unit cell. The indenyl-
idene ligands of 3, 5c and 5d are completely disordered over two
positions, torsioned over about 1661, 1501 and 1631, respectively,
with respect to each other (Fig. 4). Similar to 5a and 7a, a square-
pyramidal geometry around the ruthenium atom is observed for
the complexes. The Ru–Cl bond lengths for 3, 5b–d are within the
range of 2.379(2) Å to 2.397(2) Å and Ru–P bond lengths are found
between 2.410(1) to 2.424(4) Å. RuQC bond length are 1.83(1) and
1.88(1) Å for 3, 1.885(8) Å for 5b, 1.88(1) and 1.93(1) Å for 5c and
1.90(1) and 1.93(2) Å for 5d. Cl–Ru–Cl and P–Ru–P angles for these
four species are about 1641 and 1601, respectively.
The obtained structural information of 5a–d now allows us
to compare and analyze the structural data with the three most
famous families of ruthenium metathesis catalysts (the benzyl-
idene 1a,28 the benzylidene ether chelating 2 (see ESI†) and the
indenylidene 3 (Table 2)).
Catalytic activity of complexes 5a–d
(2)
The catalytic performance of the complexes 5a–d was tested in
comparison with the commercial available indenylidene catalyst 3
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Table 2 Selected bond lengths (Å) and angles (1) for catalysts 1a, 2, 3, 5a–d
1aa
2b
3c
3d
5a
5b
5cd
5dd
Ru–Cl
Ru–P
2.3949(6)
2.3957(6)
2.4030(7)
2.4066(7)
1.841(2)
166.87(2)
162.22(2)
2.330(1)/2.332(1)
2.331(1)/2.344(1)
2.274(1)/2.277(1)
na
1.832(5)/1.841(4)
148.81(5)/153.95(5)
na
2.389(2)
2.408(2)
2.416(2)
2.427(2)
1.882(6)
163.91(7)
159.03(7)
2.393(1)
2.394(2)
2.410(1)
2.415(1)
1.83(1)/1.88(1)
163.49(5)
159.89(5)
2.379(2)
2.400(2)
2.415(1)
2.429(1)
1.863(4)
163.33(5)
161.27(5)
2.384(3)
2.391(3)
2.414(3)
2.416(3)
1.885(8)
164.1(1)
159.6(1)
2.379(2)
2.387(2)
2.416(3)
2.422(2)
1.88(1)/1.93(1)
163.98(8)
160.66(7)
2.388(3)
2.397(2)
2.415(3)
2.424(4)
1.90(1)/1.93(1)
163.7(1)
159.3(1)
RuQC1
Cl–Ru–Cl
P–Ru–P
a
c
Data according to ref. 28. b For compound 2, the asymmetric unit contains two RuCl2(2-iso-propoxybenzylidene)(PCy3) molecules (see ESI). Data according
to ref. 29. d For compound 3, 5c and 5d, the indenylidene ligands are disordered over two parts, the RuQC distances were not restrained during refinement.
Fig. 5 RCM of substrate 11 with 3, 5a–d (0.5 mol%) at 20 1C in CDCl3
Fig. 7 RCM of substrate 13 with complex 3 and 5a–d (1 mol%) at 35 1C in
(0.6 mL), lines are intended as visual aid.
CH2Cl2 (0.1 M), lines are intended as visual aid.
In conclusion, no significant differences in the initiation
and efficiency of the examined catalysts can be drawn based on
the examined substrates and metathesis reactions.
In Table 3, the catalytic performance (expressed as the time
used for 50% conversion of 11 in the RCM reaction using
similar conditions) and the Cl–Ru–Cl angles of complexes
5a–d in comparison with other previous reported ruthenium
catalysts 2, 3, 4a and 4c are shown. As can be seen from this
table, complexes 5a–d (entries 6–9) as well as 3 (entries 2, 3)
show a much faster initiation in comparison to the chelating
ruthenium catalysts 2 and 4a–c. The time necessary to obtain
50% conversion of the substrate for the non-chelating ruthenium
indenylidene species are all around 5 minutes (entries 2, 6–9),
while for the chelating complex 2, a reaction time of 15 minutes
is required (entry 1) and for the complexes 4a and 4c, about
33 and 69 minutes are needed to obtain 50% of conversion
(entries 4, 5). On one hand, these chelating complexes show
different performance in catalytic activities, on the other hand,
they exhibit significant dissimilarities in the environments
around the ruthenium center. For example, the angles of the
Cl–Ru–Cl are 148.81(5)/153.95(5) for 2, 147.86(4) for 4a and
145.00(2) for 4c, respectively (see Table 3).23b However, for the
non-chelating catalysts 3 and 5a–d (studied in this work), the
Cl–Ru–Cl angles of the catalysts are quite similar and are merely in a
range from 163.33(5) to 164.1(1)1. Furthermore, no clear differences
Fig. 6 ROMP of COD with complexes 3, 5a–d (0.033 mol%) at 25 1C in
CDCl3 (0.6 mL), lines are intended as visual aid.
(3)
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Table 3 Comparative information of RCM of 11, using complexes 2, 3, 4a, 4c, 5a–d, together with a list of the Cl–Ru–Cl angles (1) in their crystal
structures
Entry Complexes Time for 50% conversion (minutes) Solvents Catalysts loading (mol%) Temperature (1C) Angles of Cl–Ru–Cl (1)
1a
2
2
3
3
4a
4c
5a
5b
5c
5d
B12
B5
CD2Cl2
CDCl3
CD2Cl2
CD2Cl2
CD2Cl2
CDCl3
CDCl3
CDCl3
CDCl3
1
0.5
1
1
1
0.5
0.5
0.5
0.5
30
20
30
30
30
20
20
20
20
148.81(5)/153.95(5)
163.49(5)/163.91(7)b
na
147.86(4)
145.00(2)
163.33(5)
164.1(1)
163.98(8)
163.7(1)
3a
4a
5a
6
o5
B33
B69
B5
7
8
9
B5
B5
B5
a
b
Data according to ref. 23b. Data according to ref. 29.
are observed in the bond lengths and other angles (see Table 2) methanol, toluene, THF and diethyl ether were purchased from
for species 3 and 5a–d showing once more the geometrical Fiers. Ethynyltrimethylsilane, t-butyl lithium, n-butyl lithium,
similarity between these complexes. This could be a plausible bromobenzene, di-o-tolylmethanone, potassium carbonate, diethyl
reason for the fact that no clear differences are observed in the 2,2-diallylmalonate, 1-naphthalenyl(phenyl)methanone and cis,cis-
1
catalytic performance of these complexes.
cycloocta-1,5-diene were purchased from Sigma Aldrich. H, 13C
and 31P NMR spectra were recorded on Bruker Avance 300 MHz
and 500 MHz spectrometers. Chemical shifts are listed in ppm
from tetramethylsilane with the solvent resonance as an internal
standard (1H, 13C) or external H3PO4 (31P). In the supporting
information, the exact indicated number of each assigned proton
and carbon of the new compounds and the new complexes could
Conclusions
In this work, four new air stable ruthenium indenylidene com-
plexes were successfully synthesized and isolated from moderate
to high yield. Single-crystal diffraction analyses were carried out
to fully unravel the structures of 6a, 7a and 5a–d. From these
analyses, the structures 5a–d show a similar geometry, bond
lengths as well as bond angles around the ruthenium center. All
the complexes exhibited an identical initiation and catalytic
efficiency in comparison to complex 3 in all the examined catalytic
tests. In ring-closing metathesis reaction, after 35 minutes of
reaction more than 90% of the diethyl 2,2-diallylmalonate was
converted whereas for diethyl 2-allyl-2-(2-methylallyl)malonate
more than 96% is converted after only 18 minutes of reaction.
For the ring-opening metathesis polymerization of cis,cis-cycloocta-
1,5-diene, 95% was converted after approximately 180 minutes.
Based on the current investigation, the steric modifications on the
bis-PCy3 coordinated ruthenium indenylidene catalysts showed
negligible effect on the catalytic activity. The resemblance in the
catalytic performance is most probably related to the geometrical
similarity between these complexes.
be found from the molecular structure on their H and 13C NMR
1
spectra. Elemental analyses were performed on a CHNS-0 Analyzer
from Interscience. The gas chromatography experiments were
done on a Agilent 7890A instrument equipped with a flame
ionization detector and a HP-5 5% phenyl methyl siloxane column
(DB-5, column length: 30 m, inside diameter: 0.25 mm, outside
diameter: 0.32 mm, film thickness: 0.25 mm). HPLC-MS (ESI)
measurements were performed on an Agilent NOD series HPLC
with G1946CMSD.
X-ray diffraction. For the structures of compound 5a and 7a,
X-ray intensity data were collected on a Rigaku RU200 rotating
anode equipped with a MAR345 image plate detector using
MoKa radiation (l = 0.71073 Å) and j scans. For the structures
of compounds 2, 3, 6a and 5b–d, X-ray intensity data were
collected on an Agilent Supernova Dual Source (Cu at zero)
diffractometer equipped with an Atlas CCD detector using CuKa
radiation (l = 1.54178 Å) or MoKa radiation (l = 0.71073 Å) and
o scans. All images were interpreted and integrated with the
program CrysAlisPro (Agilent Technologies).33 Using Olex2,34
the structures were solved by direct methods using the ShelXS
structure solution program35 and refined by full-matrix least-
Experimental
General consideration
All the reactions were carried out under an argon atmosphere squares on F2 using the ShelXL program.36 Non-hydrogen atoms
by using Schlenk techniques. Solvents were dried and freshly were anisotropically refined and the hydrogen atoms in the riding
distilled prior to use. For drying dichloromethane, CaH2 was used mode and isotropic temperature factors fixed at 1.2 times U(eq) of
as drying agent. Whereas for toluene, THF, diethyl ether and the parent atoms (1.5 times for methyl groups).
dioxane, sodium was employed as drying agent and benzophenone
as indicator. RuCl2(PPh3)3,31 1-( p-fluorophenyl)-1-phenyl-2-propyn-
Synthesis of the ligands
1-ol,26 1-(2,6-xylyl)-3-(trimethylsilyl)-2-propyn-1-one23b and diethyl
1,1-Di-o-tolyl-2-propyn-1-ol (6a). n-BuLi (2.5 M in hexane)
2-allyl-2-(2-methylallyl)malonate32 were prepared according to (1.5 eq., 5.7 mL, 14.28 mmol) was added drop wise to a stirred
literature procedures. Silica gel 60 (60-nominal pore diameter, solution of trimethylsilylacetylene (1.5 eq., 2 mL, 14.28 mmol) in
0.04–0.063 mm particle size) supplied by Acros Organics was used anhydrous THF (17 mL) at À90 1C under an argon atmosphere.
for flash chromatography. n-Hexane, n-pentane, ethyl acetate, After addition, the resulting solution was stirred for another
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3
3
5 minutes followed by stirring for 30 minutes at room tempera- 7.09 (t, JH,H = 10.0 Hz, 1H, H-11), 7.00 (d, JH,H = 4.5 Hz, 2H,
ture. Hereafter, di-o-tolylmethanone (1.0 eq., 2.0 g, 9.52 mmol) H-10), 2.85 (s, 1H, H-1), 2.52–2.53 (m, 1H, OH), 2.36 (s, 6H,
in dry THF (17 mL) was added slowly to the solution at À90 1C H-12). 13C{1H} NMR (75 MHz, CDCl3, 20 1C): d 144.9 (C-4), 139.1
and the resulting mixture was allowed to heat up and was (C-8), 137.0 (C-9), 130.8 (C-10), 128.6 (C-6), 128.1 (C-7), 127.3
refluxed for 30 minutes. The crude reaction mixture was quenched (C-11), 126.3 (C-5), 86.1 (C-2), 76.7 (C-3), 75.7 (C-1), 24.1 (C-12).
using 1 N HCl (15 mL) and was diluted with diethyl ether. The Anal. calcd for C17H16O (236.12): C, 86.40, H, 6.82; found: C,
organic phase was washed with water and the aqueous phases 86.38, H, 6.67. ESI-MS: [M + H]+ calcd for C17H17O, 237.1280;
were combined and extracted twice with diethyl ether, thereafter found: 237.1275; [M À OH]+ calcd for C17H15, 219.1174; found:
the ether fractions were combined and dried with anhydrous 219.1166.
MgSO4. After removal of MgSO4 by filtration, and evaporation of
1-(1-Naphthyl)-1-phenyl-2-propyn-1-ol (6d). n-BuLi (2.5 M in
the solvent, a yellow liquid was obtained. The obtained material hexane) (1.3 eq., 1.90 mL, 4.76 mmol) was added drop wise to a
was further mixed with K2CO3 (1.0 eq., 1.3 g, 9.52 mmol) in dry cold solution (À90 1C) of trimethylsilylacetylene (1.3 eq., 0.68 mL,
methanol (10 mL) and was stirred at room temperature for 4.76 mmol) in anhydrous THF (7 mL) under an argon atmosphere.
3 hours. The crude reaction mixture was quenched using 1 N After addition, the resulting solution was stirred for another
HCl (20 mL) and was diluted with diethyl ether. The organic phase 5 minutes in a cold bath and 30 minutes at room temperature.
was washed with water and the aqueous phase was extracted twice Thereafter, (1-naphthyl)(phenyl)methanone (1.0 eq. 0.85 g,
with diethyl ether, thereafter, the ether fractions were combined 3.66 mmol) in dry THF (7 mL) was added slowly to the trimethyl-
and dried on anhydrous MgSO4. Removal of MgSO4 by filtration silylacetylene solution at À90 1C and the resulting mixture was
followed by purification using flash column chromatography allowed to worm up to room temperature and vigorously stirred
(silica gel, hexane/EtOAc = 30/1) and evaporation of the solvent, for 3 hours. The crude reaction mixture was quenched by using
1
a white solid (2.06 g, 92%) was obtained. m.p. 57 1C. H NMR 1 N HCl (5 mL) and was diluted with diethyl ether. The organic
(300 MHz, CDCl3, 20 1C): d 7.92–7.97 (m, 2H, H-9), 7.20–7.26 phase was washed with water and the aqueous phase was
(m, 4H, H-7, H-8), 7.07–7.11 (m, 2H, H-6) 2.88 (s, 1H, H-1), 2.66 extracted twice with diethyl ether, thereafter the ether fractions
(s, 1H, OH), 2.02 (s, 6H, H-10). 13C{1H} NMR (75 MHz, CDCl3, were combined and dried on anhydrous MgSO4. After removal of
20 1C): d 140.6 (C-4), 136.3 (C-5), 132.3 (C-6), 128.2 (C-7), 127.2 MgSO4 by filtration, and evaporation of the solvent an oily liquid
(C-9), 125.6 (C-8), 85.5 (C-2), 76.1 (C-1), 74.8 (C-3), 21.2 (C-10). was obtained. The latter oily liquid was added to K2CO3 (1.0 eq.,
Anal. calcd for C17H16O (236.12): C, 86.40, H, 6.82; found: C, 0.5 g, 3.58 mmol) in dry methanol (4 mL) and was stirred at room
86.45, H, 6.86. ESI-MS: [M + H]+ called for C17H17O, 237.1280; temperature for 3 hours. Subsequently, methanol was removed
found: 237.1274; [M À OH]+ calcd for C17H15, 219.1174; found: followed by the addition of diethyl ether (40 mL) and water
219.1166.
(10 mL). The organic phase was separated and washed with
1-(2,6-Xylyl)-1-phenyl-2-propyn-1-ol (6c). t-BuLi (1.9 M in water; the aqueous phases were combined and extracted three
hexane) (2 eq., 7.9 mL, 15 mmol) was added drop wise to a times with diethyl ether (20 mL). Next, the organic fractions
solution of bromobenzene (1.0 eq., 1.2 g, 7.5 mmol) in dry were combined and dried on MgSO4. Removal of MgSO4 by
diethyl ether (50 mL) at À90 1C under argon atmosphere. The filtration, column chromatography (silica gel, hexane/EtOAc =
resulting solution was stirred for another 30 minutes at room 30/1) and solvent evaporation yielding a colorless sticky
temperature before slowly adding 1-(2,6-xylyl)-3-(trimethylsilyl)- material (0.8 g, 84.7%). 1H NMR (300 MHz, CDCl3, 20 1C):
3
3
2-propyn-1-one (1.1 eq., 1.9 g, 8.25 mmol) dissolved in dry d 8.16 (dd, JH,H = 7.4 Hz, 1H, H-9), 8.10 (d, JH,H = 8.7 Hz, 1H,
diethyl ether. The resulting mixture was stirred overnight at H-15), 7.82–7.90 (m, 2H, H-11, H-12), 7.59–7.62 (m, 2H, H-5),
room temperature and then quenched using a saturated NH4Cl 7.53 (t, 3JH,H = 8.1 Hz, 1H, H-10), 7.42 (td, 3JH,H = 7.5, 1.1 Hz, 1H,
(10 mL) and diluted with diethyl ether. The organic phase was H-13), 7.29–7.38 (m, 4H, H-6, H-7, H-14), 2.99 (s, 1H, OH), 2.97
washed with water and the aqueous phase were combined and (s, 1H, H-1). 13C{1H} NMR (75 MHz, CDCl3, 20 1C): d 144.1 (C-4),
extracted twice with ether, thereafter the ether fractions were 138.1 (C-8), 134.7 (C-17), 129.9 (C-16), 129.7 (C-11), 128.7 (C-12),
combined and dried on anhydrous MgSO4. After removal of 128.6 (C-6), 128.2 (C-7), 126.8 (C-15), 126.3 (C-5), 125.5 (C-14),
MgSO4 by filtration, and evaporation of the solvent an oily 125.4 (C-13), 124.8 (C-9), 124.7 (C-10), 86.2 (C-2), 76.7(C-1), 74.5
liquid was obtained. The obtained oil was mixed with K2CO3 (C-3). Anal. calcd for C19H14O (258.10): C, 88.34, H, 5.46; found:
(1.0 eq., 1 g, 7.5 mmol) in dry methanol (8 mL) and was stirred C, 88.39, H, 5.67. ESI-MS: [M + H]+ calcd for C19H15O, 259.1123;
at room temperature for 3 hours. Subsequently, methanol was found: 259.1115; [M À OH]+ calcd for C19H13, 241.1017; found:
removed by vacuum and followed by an addition of diethyl 241.1011.
ether (20 mL) and washed with 1 N HCl (15 mL). The organic
1,1-Bis(3,5-dichlorophenyl)-2-propyn-1-ol (8). Ethynylmagnesium
layer was separated and the aqueous layer was extracted twice bromide (1.2 eq., 16.8 mL, 8.4 mmol) (0.5 M in THF) was added
with diethyl ether. Next, the organic fractions were combined to bis(3,5-dichlorophenyl)methanone (1.0 eq., 2.24 g, 7 mmol)
and dried on MgSO4. Removal of MgSO4 by filtration, column in dry THF (5 mL) at room temperature. The resulting solution
chromatography (silica gel, hexane/EtOAc = 30/1) and solvent was monitored by TLC. After the completion, the crude mixture
evaporation afforded 1-(2,6-xylyl)-1-phenyl-2-propyn-1-ol as a was quenched by addition of 1 N HCl (8.4 mL) and diluted with
1
colorless oil (1.42 g, 80%). H NMR (300 MHz, CDCl3, 20 1C): diethyl ether. The organic layer was separated; the aqueous
d 7.50–7.53 (m, 2H, H-5), 7.28–7.35 (m, 3H, H-6, H-7), layer was extracted twice with diethyl ether. The organic layers
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were combined, dried on anhydrous MgSO4, filtered, and concen-
RuCl2(3-( p-fluorophenyl)-1-indenylidene)(PPh3)2 (7b). 31P{1H}
trated under vacuum. The solid was further purified by column NMR (121 MHz, CDCl3, 20 1C): d 28.3 (s).
chromatography (silica gel, hexane/EtOAc = 30/1). After the solvent
RuCl2(3-( p-florophenyl)-1-indenylidene)(PCy3)2 (5b). The obtained
evaporation a white solid (2.1 g, 86%) was obtained. m.p. 145 1C. powder was further purified using column chromatography (silica
1H NMR (300 MHz, CDCl3, 20 1C): d 7.47 (d, 4JH,H = 1.9 Hz, 4H, gel, hexane/EtOAc = 60/1) and was washed with 5 mL cold pentane
4
1
H-5), 7.30 (t, JH,H = 1.9 Hz, 2H, H-7), 2.99 (s, 1H, H-1), 2.94 (s, leaving a yellowish red powder (0.28 g, 60%). H NMR (500 MHz,
1H, OH); 13C{1H} NMR (75 MHz, CDCl3, 20 1C): d 146.5 (C-4), CDCl3, 20 1C): d 8.67 (d, JH,H = 7.6 Hz, 1H, H-7), 7.71–7.74 (m,
3
135.3 (C-6), 128.6 (C-7), 124.5 (C-5), 83.8 (C-2), 77.6 (C-1), 72.7 2H, H-11), 7.38 (s, 1H, H-2), 7.29–7.36 (m, 2H, H-5, H-6), 7.20 (d,
(C-3). Anal. calcd for C15H8Cl4O (343.93): C 52.06, H 2.33; 3JH,H = 7.0 Hz, 1H, H-4), 7.05–7.11 (m, 2H, H-12), cyclohexyl
found: C 52.43, H 2.03. ESI-MS: [M À H]À calcd for C15H7Cl4O, signals: 2.61, 1.89–1.91, 1.72–1.78, 1.65–1.66, 1.42–1.54, 1.18;
344.9222; found: 344.9216. [M–C2H2–H]À calcd for C13H5Cl4O, 13C{1H} NMR (126 MHz, CDCl3, 20 1C): d 293.3 (t, 2JC,P = 7.6 Hz,
1
318.9065; found: 318.9062.
C-1), 162.4 (d, JC,F = 247.2 Hz, C-13), 144.6 (C-8), 140.8 (C-9),
4
138.61 (C-2), 138.58 (C-3), 132.4 (d, JC,F = 3.1 Hz, C-10), 129.2
(C-7), 129.1 (C-6), 128.3 (C-5), 128.1 (d, JC,F = 7.6 Hz, C-11),
Synthesis of the catalysts
3
2
RuCl2(PPh3)3 (1.0 eq., 0.50 mmol) and propargylic alcohols 117.1 (C-4), 116.1 (d, JC,F = 21.4 Hz, C-12), cyclohexyl signals:
(1.3 eq., 0.65 mmol) were added into a 5 mL HCl–dioxane 32.7, 29.87, 27.82, 26.5. 31P{1H} NMR (202 MHz, CDCl3, 20 1C):
solution (0.1 mol LÀ1) at 90 1C. The reaction solution was d 32.3 (s). Anal. calcd for C51H75Cl2FP2Ru (940.37): C 65.09,
monitored by pilot sampling checking with 31P NMR spectrum. H 8.03; found: C 65.32, H 7.87.
After the completion, the solvent was removed under vacuum.
Hexane (20 mL) was added to the flask and the solid was (121 MHz, CDCl3, 20 1C): d 29.7 (s).
RuCl2(3-(2,6-xylyl)-1-indenylidene)(PPh3)2 (7c). 31P{1H} NMR
ultrasonically removed from the wall. The resulting suspension
RuCl2(3-(2,6-xylyl)-1-indenylidene)(PCy3)2 (5c). The obtained
was filtered and washed two times using hexane (5 mL). The powder was further purified using column chromatography
remaining solvent was evaporated affording a red-brown powder, (silica gel, hexane/EtOAc = 60/1) and was washed with 5 mL
the products were analyzed with 31P NMR to confirm the structures. cold pentane leaving a yellowish red powder (0.36 g, 76%).
The obtained ruthenium complex was dissolved in dry 1H NMR (500 MHz, CDCl3, 20 1C): d 8.70–8.71 (m, 1H, H-7),
3
dichloromethane (10 mL) and PCy3 (3.0 eq., 1.5 mmol) at argon 7.23–7.24 (m, 2H, H-5, H-6), 7.19 (s, 1H, H-2), 7.17 (t, JH,H
=
3
atmosphere and vigorously stirred at room temperature. After 7.6 Hz, 1H, H-13), 7.03 (d, JH,H = 7.3 Hz, 2H, H-12), 6.50–6.51
completion of the reaction, the resulting slurry was dried under (m, 1H, H-4), cyclohexyl and methyl signals: 2.60, 2.16 (s, 6H,
vacuum and iso-propanol (20 mL) was added. Filtration yielded H-14), 1.93–1.95, 1.73–1.79, 1.66, 1.44–1.55, 1.18–1.19. 13C{1H}
2
a red-brown powder, which after washing with iso-propanol NMR (126 MHz, CDCl3, 20 1C): d 295.6 (t, JC,P = 7.6 Hz, C-1),
(2 Â 5 mL) and drying under vacuum afforded reddish brown 143.4 (C-8), 142.7 (C-9), 141.3 (C-3), 139.8 (C-2), 135.2 (C-10),
powder.
134.2 (C-11), 129.1 (C-7), 128.9 (C-6), 128.8 (C-5), 127.4 (C-13),
RuCl2(4-methyl-3-(o-tolyl)-1-indenylidene)(PPh3)2 (7a). Brown 127.1 (C-12), 116.6 (C-4), cyclohexyl and methyl signals: 32.6,
crystals suitable for X-ray diffraction analysis were obtained by 29.8, 26.8, 26.5, 20.3 (C-14). 31P{1H} NMR (202 MHz, CDCl3,
slow diffusion of iso-propanol into a saturated dichloromethane 20 1C): d 32.9 (s). Anal. calcd for C53H80Cl2P2Ru (950.42):
solution at room temperature. 1H NMR (300 MHz, CDCl3, 20 1C): C 66.93, H 8.48; found: C 66.83, H 8.67.
d 7.54–7.56 (m, 11H), 7.32–7.40 (m, 6H), 7.21–7.30 (m, 13H),
RuCl2(3-(1-naphthyl)-1-indenylidene)(PPh3)2 (7d). 31P{1H}
7.05–7.13 (m, 3H), 6.93–6.97 (m, 3H), 6.47 (t, 3JH,H = 7.5 Hz, 1H), NMR (121 MHz, CDCl3, 20 1C): d 28.8 (s).
6.14 (s, 1H), 2.20 (s, 3H, CH3), 1.66 (s, 3H, CH3). 31P{1H} NMR
(121 MHz, CDCl3, 20 1C): d 29.3 (s).
RuCl2(3-(1-naphthyl)-1-indenylidene)(PCy3)2 (5d). The obtained
powder was further purified using column chromatography (silica
RuCl2(4-methyl-3-(o-tolyl)-1-indenylidene)(PCy3)2 (5a). (0.43 g, gel, hexane/EtOAc = 60/1) and was washed with cold pentane
1
90%). Brown crystals, suitable for X-ray diffraction analysis, were (5 mL) leaving a yellowish red powder (0.21 g, 43%). H NMR
3
obtained by slow diffusion of iso-propanol into a saturated dichloro- (500 MHz, CDCl3, 20 1C): d 8.70 (d, JH,H = 7.3 Hz, 1H, H-7),
methane solution at room temperature. 1H NMR (500 MHz, CDCl3, 7.89–7.93 (m, 3H, H-13, H-14, H-17), 7.56 (d, 3JH,H = 7.0 Hz, 1H,
20 1C): d 8.54 (d, 3JH,H = 7.6 Hz, 1H, H-7), 7.24–7.28 (m, 1H, H-15), H-11), 7.45–7.50 (m, 3H, H-2, H-12, H-15), 7.41 (t, 3JH,H = 7.5 Hz,
3
7.14–7.17 (m, 3H, H-12, H-13, H-14), 7.12 (t, 3JH,H = 7.6 Hz, 1H, H-6), 1H, H-16), 7.22–7.27 (m, 2H, H-5, H-6), 6.69 (d, JH,H = 7.6 Hz,
7.07 (s, 1H, H-2), 7.02 (d, 3JH,H = 7.6 Hz, 1H, H-5), cyclohexyl and 1H, H-4), cyclohexyl signals: 2.64, 1.96–1.99, 1.81–1.84, 1.74,
methyl signals: 2.58–2.64, 2.22 (s, H-17), 1.94, 1.74–1.78, 1.68 (s, 1.47–1.60, 1.19–1.25 ppm; 13C{1H} NMR (126 MHz, CDCl3,
2
H-16), 1.45–1.52, 1.54–1.58, 1.18–1.20. 13C{1H} NMR (126 MHz, 20 1C): d 294.9 (t, JC,P = 7.6 Hz, C-1), 143.7 (C-8), 143.1 (C-9),
CDCl3, 20 1C): d = 296.0 (t, 2JC,P = 7.6 Hz, C-1), 143.8 (C-8), 141.9 140.4 (C-2), 140.1 (C-3), 134.5 (C-10), 133.9 (C-19), 130.0 (C-18),
(C-3), 140.3 (C-2), 139.7 (C-9), 139.1 (C-11), 133.7 (C-10), 132.3 129.0 (C-6), 128.9 (C-7), 128.6 (C-5), 128.3 (C-13), 128.2 (C-14),
(C-5), 129.6 (C-12), 129.0 (C-6), 127.8 (C-4), 127.5 (C-15), 127.3 126.5 (C-17), 126.0 (C-15), 125.8 (C-16), 125.4 (C-12), 123.5
(C-7), 125.3 (C-14), 125.1 (C-13), cyclohexyl and methyl signals: (C-11), 117.7 (C-4), cyclohexyl signals: 32.8, 29.9, 27.8,
32.6, 29.8, 27.8, 25.6, 19.7 (C-17), 18.3 (C-16). 31P{1H} NMR 26.6. 31P{1H} NMR (202 MHz, CDCl3, 20 1C): d 32.1 (s). Anal.
(202 MHz, CDCl3, 20 1C): d 31.7 (q). Anal. calcd for C53H80Cl2P2Ru calcd for C55H78Cl2P2Ru (972.40): C 67.88, H 8.08; found:
(950.42): C 66.93, H 8.48; found: C 66.80, H 8.50.
C 67.80, H 8.06.
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Monitoring the catalytic process of the ruthenium com-
Paper
2 P. Schwab, M. B. France, J. W. Ziller and R. H. Grubbs,
Angew. Chem., 1995, 107, 2179–2181 (Angew. Chem., Int. Ed.
Engl., 1995, 34, 2039–2041).
plexes 3 and 5a–d.
Standard benchmark screening procedures, ROMP of COD and
the RCM catalytic tests were performed as in literature.21,30,37,38
Experimental details are given below.
3 (a) C. Samojłowicz, M. Bieniek and K. Grela, Chem. Rev.,
2009, 109, 3708–3742; (b) G. C. Vougioukalakis and R. H.
Grubbs, Chem. Rev., 2009, 110, 1746–1787; (c) K. Ofele,
E. Tosh, C. Taubmann and W. Herrmann, Chem. Rev.,
2009, 109, 3408–3444; (d) A. M. Lozano-Vila, S. Monsaert,
A. Bajek and F. Verpoort, Chem. Rev., 2010, 110, 4865–4909.
4 (a) L. Ackermann, A. Fu¨rstner, T. Weskamp, F. J. Kohl and
W. A. Herrmann, Tetrahedron Lett., 1999, 40, 4787–4790;
(b) M. Scholl, S. Ding, C. W. Lee and R. H. Grubbs, Org. Lett.,
1999, 1, 953–956; (c) M. Scholl, T. M. Trnka, J. P. Morgan
and R. H. Grubbs, Tetrahedron Lett., 1999, 40, 2247–2250;
(d) J. Huang, E. D. Stevens, S. P. Nolan and J. L. Petersen,
J. Am. Chem. Soc., 1999, 121, 2674–2678.
Applied procedure for the RCM of diethyl diallylmalonate
(11). A 0.1 M stock solution was prepared by dissolving diethyl
diallylmalonate (120 mg, 0.5 mmol) in CDCl3 (5 mL). For each
ruthenium complex, 0.00125 mmol of the precursor was added
and dissolved in CDCl3 (0.5 mL). The NMR tube was filled with
the substrate solution (0.5 mL) and the complex solution (0.1 mL).
The catalytic activity was monitored by 1H NMR spectroscopy
during the examined time interval. The catalytic tests were
done at 20 1C.
Applied procedure for the ROMP of COD. The ruthenium
complex (0.00163 mmol) was weighted and dissolved in CDCl3
(0.6 mL). Then, An NMR tube is charged with COD (0.1 mL) and
CDCl3 (0.5 mL). After adding the ruthenium solution (0.1 mL),
the NMR tube was closed and subjected in to measurement.
The catalytic tests were done at 25 1C. The conversion was
determined by integration of the olefinic 1H NMR signals of the
formed polymer and the consumed monomer.
Applied procedure for the RCM of diethyl 2-allyl-2-(2-
methylallyl)malonate (13). The substrate, diethyl 2-allyl-2-(2-
methylallyl)malonate (0.25 g, 1 mmol) and dodecane (0.17 g,
1 mmol), was employed as an internal standard, were added in
a Schlenk vessel and flushed with argon. CH2Cl2 (9 mL) was
added and the solution was heat up to 35 1C. Then, 1 mol% of
the catalyst in CH2Cl2 (1 mL) was added. During the reaction
aliquots were taken out from the reaction mixture and were
diluted with CH2Cl2 and ethoxyethene before GC analysis.
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Acknowledgements
K. V. H. thanks the Hercules Foundation (project AUGE/11/029
‘‘3D-SPACE: 3D Structural Platform Aiming for Chemical Excel-
lence’’) for funding. Y. X. and F. V. would like to express their
deep appreciation to the State Key Lab of Advanced Technology
for Materials Synthesis and Processing for financial support
(Wuhan University of Technology). F. V. acknowledges the
Chinese Central Government for an Expert of the State position
in the program of Thousand Talents and the support of the
Natural Science Foundation of China (No. 21172027). B. Y. and
F. V. appreciate the Research Fund – Flanders (FWO) (project
No. 3G022912) for funding. K. L. acknowledges the Special
Research Fund of Ghent University for a postdoctoral grant
(No. 01P06813T).
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