FT Raman - A valuable tool for surveying kinetics in RCM of functionalized dienes

Article abstract of DOI:10.1016/j.saa.2010.05.001

In this article the suitability of FT Raman spectroscopy for monitoring kinetics of ring-closing metathesis promoted by the Grubbs' 1st generation precatalyst was demonstrated for the first time. Reactions at room temperature and under low catalyst loadings were carried out on a series of representative diene substrates. The time evolution of the characteristic Raman stretching vibrations unequivocally described the reaction progress allowing for precise calculation of the substrate conversion and of the yield in the expected cyclic product, based on the corresponding peak heights. The responsive Raman technique demonstrated clean RCM pathways for diethyl diallylmalonate and diallyl ether whereas a minor olefinic side-product was detected in the case of diallyl phthalate. The study provides essential underpinnings for future utilization of Raman spectroscopy, concurrently with NMR or supplementing it, for the evaluation of RCM reactions.

Full text of DOI:10.1016/j.saa.2010.05.001

Spectrochimica Acta Part A 77 (2010) 170–174
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
FT Raman—A valuable tool for surveying kinetics in RCM of functionalized dienes
Fu Dinga,b, Baoyi Yu , Stijn Monsaert , Ya-guang Sun , Enjun Gao , Ileana Dragutan ,
a
a
b
b
c
c
a,∗
Valerian Dragutan , Francis Verpoort
Organometallics and Catalysis, Department of Inorganic and Physical Chemistry, Ghent University, Ghent 9000, Belgium
Laboratory of Coordination Chemistry, Shenyang Institute of Chemical Technology, Shenyang 100142, China
Institute of Organic Chemistry of the Romanian Academy, Bucharest, Romania
a
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
In this article the suitability of FT Raman spectroscopy for monitoring kinetics of ring-closing metathesis
promoted by the Grubbs’ 1st generation precatalyst was demonstrated for the first time. Reactions at
room temperature and under low catalyst loadings were carried out on a series of representative diene
substrates. The time evolution of the characteristic Raman stretching vibrations unequivocally described
the reaction progress allowing for precise calculation of the substrate conversion and of the yield in
the expected cyclic product, based on the corresponding peak heights. The responsive Raman technique
demonstrated clean RCM pathways for diethyl diallylmalonate and diallyl ether whereas a minor olefinic
side-product was detected in the case of diallyl phthalate. The study provides essential underpinnings for
future utilization of Raman spectroscopy, concurrently with NMR or supplementing it, for the evaluation
of RCM reactions.
Received 25 December 2009
Received in revised form 11 April 2010
Accepted 12 May 2010
Keywords:
FT Raman
Ring-closing metathesis
1
H NMR
Kinetics
Functionalized dienes
©
2010 Elsevier B.V. All rights reserved.
1
. Introduction
products of this type of alkene metathesis have been thoroughly
investigated by a variety of physical techniques, frequently used in
combination, such as gas-chromatography, H NMR, C NMR, ESR,
FT-IR, MALDI-TOF MS, Raman spectroscopy, etc. [16–21].
1
13
Olefin (alkene) metathesis is today a well-recognized pathway
for formation of new carbon–carbon bonds. As eloquently illus-
trated in excellent books [1–4] and general reviews [5–8], this
reaction enjoys wide application in organic synthesis and materials
science.
Of analytical methods, Fourier transform Raman spectroscopy is
both non-destructive and suitable for remote analysis (even while
the sample is placed inside containers), with no need for spe-
cial sample preparation. The technique enables fast and accurate
measurements on a broad range of samples, be it solids or water-
containing specimens. Advanced Raman instruments also allow in
situ observation at different depths inside materials. It should be
kept in mind that for the successful recording of FT Raman spec-
tra of small samples a compromise between large lateral resolution
and a large signal/noise ratio has to be found.
Due to the flexibility of the method and improvement of
the Fourier transform Raman instrumentation, this non-invasive
technique has enormous potential for a widespread range of appli-
cations (agrochemical industry, control of pesticide formulations,
biodiagnosis, in pharmaceutical production, measurement of APIs
in real drug formulations and inside packaging) where high sen-
sitivity needs to be combined with good discrimination between
molecular targets [22]. Simplicity and speed make Raman spec-
troscopy a viable technique for the industrial user. Real time FT
Raman spectroscopy also finds utilizations in on-line process mon-
itoring, e.g. in routine quality work within factory environments.
Today Raman-based spectroscopic methods have evolved to the
stage where they can be used as quantitative analytical techniques.
Along this line, the present research examines, for the first time,
Among metathesis-based strategies, ring-closing metathesis
(
RCM) was the first to act as engine towards success, particularly
as preferred key-step in unparalleled short syntheses of natural
products or of their mimics, of intricate frameworks with targeted
stereochemistry, of pharmaceuticals or amphiphilic molecules
prone to self-assemble, etc., all promoting olefin metathesis to the
forefront of synthetic protocols [9–13]. RCM is the procedure of
choice for macrocyclization, frequently encountered in the total
synthesis of drugs and natural products, and essential also for
developing derivatives that modulate biological activity or phar-
macokinetic properties [14]. Not surprisingly, at present, RCM (and
ARCM) and cross metathesis attract more and more the attention of
metathesis researchers due to their versatility in combining a host
of substrates to produce long desired multifunctional compounds,
scientifically and economically valuable [15].
Due to the recent impact and great utility of RCM in organic
synthesis, the kinetics, mechanism and structure of the reaction
∗ Corresponding author. Tel.: +32 9 264 4436; fax: +32 9 264 4983.
E-mail address: francis.verpoort@ugent.be (F. Verpoort).
1
386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.05.001

F. Ding et al. / Spectrochimica Acta Part A 77 (2010) 170–174
171
Fig. 1. Grubbs’ 1st generation catalyst (Cy = cyclohexyl).
the capabilities of FT Raman in monitoring RCM reactions of diene
substrates which have been selected so as to yield functionalized
cyclic olefins of different sizes and ring strains. In all experiments
ring closure is promoted by the well-defined initiator known as the
Grubbs 1st generation catalyst (Fig. 1), under low catalyst loadings.
Whereas Raman spectroscopy and in-line fibre-optic NIR-FT
Raman spectroscopy have been previously applied to studies
on a different type of metathesis reactions, i.e. ring-opening
metathesis (ROMP of norbornene, dicyclopentadiene, and exo,exo-
Fig. 2. FT Raman spectra for RCM of diethyl diallylmalonate (DEDAM) (2.5 M in
CH2Cl2), promoted by the Grubbs I catalyst (0.4 mol%), recorded at variable time
(
0–60 min) in a closed vessel.
5
,6-di(methoxycarbonyl)-7-oxabicyclo[2.2.1]hept-2-ene) [23–25],
to the best of our knowledge there is to date no report on a Raman-
based investigation of the metathesis of olefins by ring-closing. A
further goal of the paper is to compare the kinetic data arising
from Raman spectroscopy with existing information collected by
other spectroscopic methods, particularly by NMR. Most impor-
tantly, we aim to assess the suitability of Raman spectroscopy as
a tool for quantitative observation also of ring-closing metathe-
sis, a reaction forming a cycle and not opening one as happens in
ring-opening metathesis (ROM) or ring-opening metathesis poly-
merization (ROMP).
previously applied for Raman evaluation of ROMP of norbornene
has been followed [23]. To minimize variations in intensity of the
excitation laser line we used, as necessary, a reference band from
the spectrum which remains constant during the RCM reaction, in
our case the 704 cm band pertaining to the methylene chloride
used as the solvent.
−
1
Five standard solutions with different substrate concentrations
were prepared for each substrate (e.g. for diallyl ether: 0, 0.4991,
0
.9845, 1.5026, 1.9894, 2.5281 and 3.0027 mol/L) and measured
2
. Materials and methods
five times each by in-line Raman. Measurement conditions for con-
structing the calibration curve were 50 scans, laser power 200 mW,
−
1
2.1. Spectroscopic conditions
room temperature and 4 cm resolution, with the substrate peaks
−
1
appearing at 1642, 1647 and 1649 cm for DEDAM (Fig. 2), DAE
(Fig. 3) and diallyl phthalate (Fig. 5), respectively, and the reference
A Bruker FT spectrometer Equinox 55S with Raman module FRA
06, a hybrid FT-IR/FT Raman spectrometer, fitted with a germa-
−
peak (CH Cl ) at 704 cm . For each measurement the height of the
2 2
1
1
nium high sensitivity detector D418-T (cooled by nitrogen at 77 K)
was used. During the monitoring of RCM, the excitation laser wave-
length of 1064 nm was produced by an air cooled diode pumped
neodyniumyttrium aluminium garnet laser (Nd:YAG). The spectral
substrate peak was corrected by that of the reference (solvent). For
every standard solution the average of the corrected peak height
(resulting from five successive measurements) was considered.
Eventually a calibration curve was obtained in which the rela-
tive intensity, y (i.e. intensity of the substrate peak/intensity of the
reference peak) was plotted as a function of the substrate concen-
tration, x [23]. In the investigated domain of concentrations a linear
relationship was found, e.g. for diallyl ether: y = 0.1431x − 0.0324
−1
coverage extends from 100 to 4000 cm , with a spectral resolution
of 4 cm−1, number of scans (50), laser power (200 mW). Spectra
were recorded at 6 min intervals during a total time of 60 min. Data
transfer, collection and processing were fully automated using a
TM
2
Bruker OPUS software.
(R = 0.9957). Based on the calibration curve, the degree of substrate
conversion could be calculated from the known initial substrate
concentration and the transient substrate concentration (above the
detection limit), as determined by Raman at a time t.
2.2. Choice of the solvent
Raman spectroscopy can use cheap solvents. In addition exper-
imental wavenumbers in Raman spectra are independent of the
solvent (which is not the case in NMR spectroscopy). However,
in RCM some limiting conditions are imposed on the solvent
which must not deactivate the catalyst (traces of moisture or
oxygen should be avoided because of the sensitivity of the cata-
lyst) [3]. A further restriction comes from the fact that in Raman
spectra no interference from the solvent with the C C stretch-
ing vibration (ꢀC C) of the substrate and the product should occur
−
1
(
no solvent peaks in the range 1500–1800 cm are admissible).
Dichloromethane was chosen as the ideal solvent for this Raman
study of RCM reactions.
2.3. Calibration curves
Crucial to precise measurements by Raman is to first construct
a calibration curve for determining the relationship that exists
between the intensity of the Raman signal and the concentration of
the substrate. Calibration curves were built up for each of the three
substrates examined in this RCM study. The same methodology as
Fig. 3. FT Raman spectra for RCM of diallyl ether (DAE) (2.5 M in CH2Cl2), promoted
by the Grubbs I catalyst (0.4 mol%), recorded at variable time (0–60 min.).

1
72
F. Ding et al. / Spectrochimica Acta Part A 77 (2010) 170–174
2.4. Monitoring of ring-closing metathesis by FT Raman
spectroscopy. Substrate conversions vs. time have been calculated
from peak heights in spectra recorded at precise time intervals.
Most relevant data are illustrated in Figs. 2–6.
The ring-closing metathesis reaction was carried out in
a glass vessel (7 ml) equipped with a magnetic stirring bar.
(
(
1)
2)
(3)
The diene substrate was dissolved in 1 ml CH Cl2 under magnetic
2
stirring and the FT Raman spectrum was recorded to obtain the
intensity of its C C stretching vibration at time t = 0. Next, the
catalyst was added to the substrate solution, the vial containing
the reaction mixture placed in the sample compartment of the
FT Raman spectrometer, and evolution of the RCM was monitored
under the same measurement conditions as employed for the cali-
3
.1.1. RCM of diethyl diallylmalonate
We first focused on ring-closing of diethyl diallylmalonate
DEDAM) (Eq. (1)), the most studied substrate, in particular by
(
1
13
H and C NMR spectroscopy. The Raman-inferred evolution in
time of DEDAM conversion to the expected RCM product, 3,3-
carbethoxy-1-cyclopentene, is presented in Fig. 2. Curves in Fig. 2
correspond to Raman spectra collected at distinct time intervals
extending over 1 h of reaction surveillance.
The 1st generation Grubbs catalyst is a fast-initiating promoter
of RCM of this active substrate (see Section 3.2). While the reac-
−
1
bration curves (50 scans; laser power, 200 mW; resolution, 4 cm
room temperature). Conversions were determined from the ratio
;
−
1
between the height of the substrate peak (e.g. 1642 cm , Fig. 2),
−
1
relative to the height of the reference peak (704 cm ), at a time
t and at the time zero (t = 0, i.e. in the initial substrate solution).
The area under the peak varies linearly with the peak height if
resolution is considerably better than the band half-width, which
is the case here (Figs. 2, 3 and 5). A small error in placing the
background greatly affects the area integral, but less so the peak
height, so use of peak heights rather than peak areas is more reliable
−1
tion (run in a closed vessel) is progressing, the peak at 1642 cm
(stretching vibration of C C double bonds pertaining to the allylic
groups of the diolefin substrate) is decreasing. A concomitant
appearance of a new band at 1623 cm is attributed to vibrations
of the endocyclic double bond incorporated in the five-membered
carbocyclic product which is being generated in RCM (Fig. 2). The
−1
[
23].
−1
rapid increase in height of band at 1623 cm
corresponds to a
growing conversion, as calculated from the Raman spectra vs. time.
3
. Results and discussion
Under our low catalyst loading (0.4 mol%), conversion reaches 77%
◦
after 1 h at 16 C, a result paralleling that (ca. 84% conversion; the
green plot in Fig. 6) earlier reported from 1H NMR measurements
Research in our group has a long standing focus in both
RCM reactions [26] and in Raman spectroscopy [23–25]. So far
RCM has largely been followed by NMR, with kinetics frequently
determined through measurements effected directly in the NMR
tube. However, Raman has obvious advantages over NMR spec-
troscopy: no deuterated solvent and no special analysis tubes
are needed, a smaller amount of substrate is necessary, no
viscosity changes can influence the accuracy of kinetics exper-
iments. Besides, since FT Raman spectroscopy is effective for
molecules whose polarization degree changes by oscillation, the
new C C vibrations appearing as a result of RCM are clearly
identifiable when the intensities of the characteristic ꢀC C bands
in the substrate and in the product change during the reac-
tion.
in CDCl3 (with the same catalyst, yet at a slightly elevated tem-
perature (20 C) and at a higher catalyst/substrate ratio (0.5 mol%))
◦
[27]. The absence of additional Raman vibrations, other than the
−
1
legitimate 1642 and 1624 cm , is a clear indication that under our
experimental setting RCM of diethyl diallylmalonate is a clean pro-
cess, not accompanied by side-reactions, in agreement with the
wealth of literature data based on NMR reported for Grubbs I and
later introduced ruthenium catalysts.
3.1.2. RCM of diallyl ether
On changing now to a different substrate, the diallyl ether,
where the two allyl substituents are connected by a heteroatom
O) instead of the C atom from the above diethyl diallyl malonate,
(
we applied the FT Raman spectroscopy to kinetically follow RCM
leading to a five-membered oxocyclic product (Eq. (2), Fig. 3). Again
3
.1. RCM of diene substrates in the presence of the Grubbs I
−
1
catalyst
the expected decrease of the peak (1647 cm ) corresponding to
stretching vibrations of C C double bonds in diallyl ether is notice-
−
1
Kinetics of RCM reactions of selected diolefin substrates includ-
ing diethyl diallylmalonate, diallyl ether and diallyl phthalate (Eqs.
1)–(3), respectively), initiated in all cases by the well-defined
Grubbs Icatalyst (Fig. 1), have been examined by means of FT Raman
able and is accompanied by an augmenting new signal at 1619 cm
assigned to the endocyclic double bond in the product. The reac-
tion is initially fast, with ca. 30% conversion being attained within
the first 2 min but then slows down (after 10 min, 50% conversion)
(

F. Ding et al. / Spectrochimica Acta Part A 77 (2010) 170–174
173
Fig. 4. Conversion plots for RCM reactions of diallyl ether (2.5 M in CH2Cl2), pro-
moted by the Grubbs I catalyst (0.4 mol%), conducted under Ar, in air (open vessel)
or autogenic pressure (closed vessel).
Fig. 6. Conversion plots for RCM reactions of diethyl diallylmalonate, diallyl ether
and diallyl phthalate (2.5 M in CH2Cl2), promoted by the Grubbs I catalyst (0.4 mol%)
and conducted under autogenic pressure (closed vessel), as determined by Raman
1
spectroscopy and H NMR (green plot [27]).
leveling subsequently to a plateau (Figs. 3 and 4). Moreover, Raman
spectra evidence a third, minor peak slowly increasing in time at
−1
1
680 cm (unidentified olefinic side-product). As compared with
diallylmalonate and diallyl ether, gave rise by RCM to 5-membered
cyclic products, diallyl phthalate may only ring-close to a 10-
membered oxocyclic product having a different ring strain and
stereoconfiguration. Therefore, a priori the reaction must proceed
distinctly with respect to both kinetics and thermodynamics. In
truth, FT Raman spectra vs. time (Fig. 5), indicate the expected
diethyl diallyl malonate, this behaviour is indicative of a less reac-
tive substrate, allowing for side-reactions to also intervene along
with the ring-closing process. A plausible rationalization of the
reaction level after the 50% conversion is a competing complexa-
tion of the ether oxygen atom from the substrate to the ruthenium
core of the Grubbs I catalyst, generally considered to be very sensi-
tive to functionalities and therefore having limited applications in
such cases. Blocking some of the catalyst as a metathesis inactive
species (vibrating in Raman outside the recorded domain of the
spectrum) may prevent RCM to progress with complete conver-
sion to the desired product, especially under low catalyst loading
as is our case. Indeed, RCM of dienes containing ether functionali-
ties is not a frequently encountered reaction in the metathesis body
of knowledge, high RCM yields been reported only for higher cat-
alyst concentrations (2–5 mol%)[28] or in template-directed RCM
where oxygen atoms are coordinated by metal cations [29]. A fur-
ther support for the formation of a complex between the catalyst
and the substrate comes from results depicted in Fig. 4 which
unquestionably evidence that the plateau occurs at ca. 50% con-
version irrespective of the experimental conditions under which
RCM was conducted (under Ar, in an open vessel or in a closed ves-
sel (autogenic pressure)), conditions that normally influence both
the reaction equilibrium and the integrity of the catalyst.
−
1
slower decrease in height of the stretching vibration at 1649 cm
(allylic C C from the starting material) and the simultaneous
−
1
growth of the band at 1681 cm , attributed to the endocyclic C
C
of the 10-membered ring product. The product arises at a compara-
tively reduced rate (ca. 30% yield after 60 min) (Fig. 6). Fortunately,
the remarkable sensitivity and discriminatory power of the Raman
spectroscopic technique allows detection of a minor side-product
−
1
(1619 cm , Fig. 5) emerging along with the targeted benzoan-
nelated compound during RCM of this sluggish diene substrate.
More importantly, based on the exquisite resolution of the band
specific to the starting material, a quantitative evaluation of the
Raman spectrum is still possible—a condition rarely fulfilled by
NMR spectra of mixed olefinic products.
3.2. Dependence of conversion in RCM on the diene substrate
Results obtained in our FT Raman investigation of RCM of diethyl
diallylmalonate, diallyl ether and diallyl phthalate using the Grubbs
1
st generation catalyst undoubtedly indicate that, under identical
3
.1.3. RCM of diallyl phthalate
Interesting results have also been collected from the Raman-
reaction conditions, the evolution of conversion in time essentially
depends on the nature of the diene substrate. Of the three investi-
gated substrates, DEDAM proved to be the most active, reaching a
conversion of 77% after 60 min and 90% after 100 min (not shown),
even under the unusually low catalyst loading we choose to employ
in our experiments for the sake of accuracy. In this series, diallyl
phthalate is the least active diene, giving in RCM a 30% conversion
within the same reaction time (Fig. 6). This behavioural discrepancy
arises from the unlike ring-strain associated with the ring-closure
process (5-membered rings for the first two substrates and a 10-
membered ring for diallyl phthalate), and also from differences in
steric hindrance of the conformations that the cyclic compounds
may adopt. Whereas a cis configuration of the endocyclic double
bond is present in all three RCM products, in the 10-membered het-
erocycle the double bond is forced out of the plane of the adjacent
conjugated moiety (phenyl ring and COO groups).
monitored RCM of diallyl phthalate, in the presence of the same
Grubbs I catalyst (Fig. 5). While the previous two substrates, diethyl
4. Conclusions
For the first time, the present research gives convincing evidence
on the utility and assets of FT Raman spectroscopy in accurately
monitoring kinetics of RCM reactions promoted by the 1st genera-
Fig. 5. FT Raman spectra for RCM of diallyl phthalate (2.5 M in CH2Cl2), promoted
by the Grubbs I catalyst (0.4 mol%), recorded at variable time (0–60 min.).

1
74
F. Ding et al. / Spectrochimica Acta Part A 77 (2010) 170–174
tion Grubbs catalyst. Advantage was taken of a set of functionalized
diene substrates (diethyl diallylmalonate, diallylether and dial-
lyl phthalate) chosen so as to have distinct tendenties for RCM.
Even under low catalyst loading (0.4 mol%) and the otherwise very
mild conditions employed, the evolution in time of the charac-
teristic Raman vibrations could unequivocally reveal the reaction
progress allowing for a precise calculation of the substrate conver-
sion, at every reaction time, from the corresponding peak height.
The sensitivity of the Raman technique gave proof of clean RCM
pathways for diethyl diallylmalonate and diallyl ether whereas
a minor olefinic side-product was detected in the case of diallyl
phthalate. Results from this Raman investigation on RCM of diethyl
diallylmalonate compare well with data acquired earlier in our
(e) F. Verpoort, I. Dragutan, V. Dragutan, Olefin Metathesis,
http://www.scitopics.com/Olefin Metathesis.html;
(
f) M.R. Buchmeiser, Chem. Rev. 109 (2009) 303–321.
9] K.C. Nicolaou, P.G. Bulger, D. Sarlah, Angew. Chem. Int. Ed. 44 (2005) 4490–4527.
[10] F. Amblard, S.P. Nolan, L.A. Agrofoglio, Tetrahedron 61 (2005) 7067–7080.
[
[
[
[
11] V. Dragutan, I. Dragutan, J. Organomet. Chem. 691 (2006) 5129–5147.
12] P. Compain, Adv. Synth. Catal. 349 (2007) 1829–1846.
13] W.A.L. van Otterlo, C.B. de Koning, Chem. Rev. 109 (2009) 3743–3782.
[14] A. Gradillas, J. Pérez-Castells, Angew. Chem. Int. Ed. 45 (2006) 6086–6101.
[15] (a) R. Malacea, C. Fischmeister, C. Bruneau, J.-L. Dubois, J.-L. Couturier, P.H.
Dixneuf, Green Chem. 11 (2009) 152–155;
(
b) M.A.R. Meier, Macromol. Chem. Phys. 210 (2009) 1073–1079;
(c) B. De Clercq, F. Lefebvre, F. Verpoort, New J. Chem. 26 (2002) 1201–1208;
(d) T. Opstal, K. Couchez, F. Verpoort, Adv. Synth. Catal. 345 (2003) 393–401.
16] M. Bassetti, F. Centola, D. Semeril, C. Bruneau, P.H. Dixneuf, Organometallics 22
[
[
[
[
[
[
(
2003) 4459–4466.
17] M. Rosillo, G. Domingez, L. Casarrubios, U. Amador, J. Perez-Castells, J. Org.
Chem. 69 (2004) 2084–2093.
18] R. Guan, Ch. Zhou, Sh. Feng, D.J. Berg, S.R. Stobart, J. Chin. Chem. Soc. (Taipei,
Taiwan) 52 (2005) 113–118.
1
group by H NMR. Overall, this study highlights the potentiality
of Raman spectroscopy as a worthy research tool for the extremely
dynamic domain of metathesis chemistry.
19] B.R. Galan, A.J. Giessert, J.B. Keister, S.T. Diver, J. Am. Chem. Soc. 127 (2005)
5
762–5763.
20] C. Ornelas, D. Mery, E. Cloutet, J. Ruiz Aranzaes, D. Astruc, J. Am. Chem. Soc. 130
2008) 1495–1506.
21] M.A. Ba n˜ ares, G. Mestl, Adv. Catal. 52 (2009) 43–128.
Acknowledgements
(
ID, VD and FV thank FWO-Flanders for financial support during
elaboration of this work. FV and FD are indebted to Ghent University
for financial support.
[22] (a) T. Vankeirsbilck, A. Vercauteren, W. Baeyens, G. Van der Weken, F. Verpoort,
G. Vergote, J.P. Remon, TrAC Trends Anal. Chem. 21 (2002) 869–877;
(
b) T.R.M. DeBeer, G.J. Vergote, W.R.G. Baeyns, J.P. Remon, C. Vervaert, F. Ver-
poort, Eur. J. Pharm. Sci. 23 (2004) 355–362;
c) S. Cinta Pinzaru, I. Pavel, N. Leopold, W. Kiefer, J. Raman Spectrosc. 35 (2004)
38–346;
d) G. Zhou, R. Guenard, Z. Ge, in: D.E. Pivonka, J.M. Chalmers, P.R. Griffith (Eds.),
(
3
(
References
Application of Vibrational Spectroscopy in Pharmaceutical Research and Devel-
opment, John Wiley, Chichester, UK, 2007, pp. 185–211;
[
[
[
[
1] K.J. Ivin, J.C. Mol, Olefin Metathesis and Metathesis Polymerization, Academic
Press, London, 1997.
2] V. Dragutan, A.T. Balaban, M. Dimonie, Olefin Metathesis and Ring-opening
Metathesis Polymerization of Cycloolefins, John Wiley, Chichester, UK, 1985.
3] R.H. Grubbs (Ed.), Handbook of Metathesis, vols. I–III, Wiley–VCH, Weinheim,
(
e) S. Armenta, G. Quintas, S. Garrigues, M. de la Guardia, TrAC Trends Anal.
Chem. 24 (2005) 772–781;
(
(
f) S.-Y. Lin, M.-J. Li, W.-T. Cheng, Spectroscopy 21 (2007) 1–30;
g) J.W. Niemantsverdriet, A Wide Spectrum for Analysis: Spectroscopy in
2
003.
Catalysis. An Introduction, VCH, Weinheim, 1993;
h) M.H. Jamróz, M.E. Jamróz, J.E. Rode, E. Bednarek, J.Cz. Dobrowolski, Vibra-
4] (a) Y. Imamoglu, V. Dragutan (Eds.), Metathesis Chemistry: From Nanostructure
Design to Synthesis of Advanced Materials, Springer, Dordrecht, The Nether-
lands, 2007;
(
tional Spectrosc. 50 (2009) 231–244.
[
[
[
[
23] B. De Clercq, T. Smellinckx, C. Hugelier, N. Maes, F. Verpoort, Appl. Spectrosc.
(
b) V. Dragutan, A. Demonceau, I. Dragutan, E.Sh. Finkelshtein (Eds.), Green
55 (2001) 1564–1567.
Metathesis Chemistry: Great Challenges in Synthesis, Catalysis and Nanotech-
nology, Springer, Dordrecht, The Netherlands, 2010.
5] (a) R.R. Schrock, R.H. Grubbs, A. Furstner (Eds.), Special Issue: Olefin Metathesis,
24] D. Schaubroeck, S. Brughmans, C. Vercaemst, J. Schaubroeck, F. Verpoort, J. Mol.
Catal. A: Chem. 254 (2006) 180–185.
25] F. Ding, S. Monsaert, R. Drozdzak, I. Dragutan, V. Dragutan, Y. Sun, E. Gao, P. Van
Der Voort, F. Verpoort, Vibrational Spectrosc. 51 (2009) 147–151.
26] (a) B. De Clercq, F. Verpoort, Tetrahedron Lett. 43 (2002) 9101–9104;
[
Adv. Synth. Catal., 349, 2007, pp. 1–265;
(
b) R.R. Schrock, Chem. Rev. 109 (2009) 3211–3226.
6] (a) A.H. Hoveyda, A.R. Zhugralin, Nature 450 (2007) 243–251;
b) P.H. Deshmukh, S. Blechert, Dalton Trans. (2007) 2479–2491.
[
[
(
b) N. Ledoux, A. Linden, B. Allaert, H. Vander Mierde, F. Verpoort, Adv. Synth.
(
Catal. 349 (2007) 1692–1700;
7] (a) H. Clavier, K. Grela, A. Kirschning, M. Mauduit, S.P. Nolan, Angew. Chem. Int.
Ed. 46 (2007) 6786–6801;
(
(
c) T. Opstal, F. Verpoort, J. Mol. Catal. A: Chem. 200 (2003) 49–61;
d) N. Ledoux, R. Drozdzak, B. Allaert, A. Linden, P. Van Der Voort, F. Verpoort,
(
b) R. Drozdzak, N. Ledoux, B. Allaert, I. Dragutan, V. Dragutan, F. Verpoort, Cent.
Dalton Trans. (2007) 5201–5210;
e) S. Monsaert, E. De Canck, R. Drozdzak, P. Van Der Voort, F. Verpoort, J.C.
Eur. J. Chem. 3 (2005) 404–416.
8] (a) V. Dragutan, I. Dragutan, L. Delaude, A. Demonceau, Coord. Chem. Rev. 251
(
[
Martins, P.M.S. Hendrickx, Eur. J. Org. Chem. (2009) 655–665.
27] S. Monsaert, R. Drozdzak, V. Dragutan, I. Dragutan, F. Verpoort, Eur. J. Inorg.
Chem. (2008) 432–440.
(
(
2007) 765–794;
[
[
b) F. Ding, Y. Sun, S. Monsaert, R. Drozdzak, I. Dragutan, V. Dragutan, F.
Verpoort, Curr. Org. Synth. 5 (2008) 291–304;
c) S. Monsaert, R. Drozdzak, F. Verpoort, Chim. Oggi/Chem. Today 26 (2008)
3–96;
d) A.M. Lozano, A. Bajek, S. Monsaert, R. Drozdzak, F. Verpoort, Chim.
Oggi/Chem. Today 27 (3) (2009) 20–23 (Suppl. “Focus on Metathesis”);
28] (a) B. Schmidt, H. Wildemann, Eur. J. Org. Chem. (2000) 3145–3163;
(
9
(
(
(
b) D.-W. Hahn, D.-M. Byun, J. Tae, Eur. J. Org. Chem. (2005) 63–67;
c) B. Schmidt, J. Mol. Catal. A: Chem. 254 (2006) 53–57.
[
29] H.D. Maynard, R.H. Grubbs, Macromolecules 32 (1999) 6917–6924.