Isocyanate- and isothiocyanate-derived RuIV-based alkylidenes: Synthesis, structure, and activity

Article abstract of DOI:10.1002/asia.200900099

The synthesis and characterization of a series of isocyanate- and isothiocyanate-derived second generation Grubbs-Hoveyda-type ruthenium- alkylidene complexes, that is, [Ru(N= C=O)₂(IMesH₂)(=CH-2- (2-PrO)-C₆H₄)]

Full text of DOI:10.1002/asia.200900099

DOI: 10.1002/asia.200900099
IV
Isocyanate- and Isothiocyanate-Derived Ru -Based Alkylidenes: Synthesis,
Structure, and Activity
[
a]
[b]
[a, c]
P. Santhosh Kumar, Klaus Wurst, and Michael R. Buchmeiser*
Abstract: The synthesis and characteri-
zation of a series of isocyanate- and
isothiocyanate-derived second genera-
tion Grubbs–Hoveyda-type ruthenium–
and [RuCl (1,3-dimesityl-3,4,5,6-tetra-
content of about 80%. First-order ki-
netics with unprecedentedly high rate
2
hydropyrimidin-2-ylidene)
ACTHUNGTNERNUNG( =CH-2- ACHTUNGRTENNUNG( 2-
PrO)-C H )] (6) with silver cyanate
constants of polymerization (k =0.068
6
4
p
À1
and thiocyanate, respectively. The X-
ray structure of 1 was determined, con-
firming the isocyanate-type bonding of
the ligand. The isothiocyanate-type
bonding in 3 and 4 was unambiguously
and 0.26 s , respectively) were ob-
alkylidene complexes, that is, [Ru
C=O) (IMesH )(=CH-2-(2-PrO)-
(N=C=O) (1,3-dimesi-
A
H
U
G
R
N
U
G
served. Compounds 3 and 4 were also
active initiators for the ROMP of
COD, however, they generated poly-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
ACHTUNGTRENNUNG
2
ACHTUNGTRENNUNG
2
C H )] (1), [Ru
ACHTUNGTRENNUNG
6
4
2
tyl-3,4,5,6-tetrahydropyrimidin-2-
ylidene)(=CH-2-(2-PrO)-C H )]
Ru(N=C=S) (IMesH )
PrO)-C H )] (3), and [Ru
ACHTUNGTRNENUNG( COD) with a cis-content of 80 and
1
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2),
confirmed by IR and C NMR spec-
troscopy. The isocyanate-derived com-
plexes 1 and 2 were found to be excel-
lent catalysts for the ring-opening
metathesis polymerization (ROMP) of
cis-cycloocta-1,5-diene (COD). Both 1
67%, respectively. Complexes 1 and 2
also showed good catalytic activity in
cross-metathesis (CM) reactions. Final-
ly, 1–4 were also found to be excellent
catalysts for the regioselective cyclopo-
lymerization of diethyl 2,2-dipropargyl-
malonate (DEDPM), resulting in poly-
AHCTUNGTRENNUNG( DEDPM) almost entirely based on
five-membered repeat units, that is, cy-
clopent-1-ene-1,2-vinylenes.
6
4
[
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
ACHTUNGERTNNU(GN =CH-2- ACHTNUGTRENUGNN
2
2
AHCTUNGTRENNUNG
6
4
2
midin-2-ylidene)
ACHTUNGTRENNUNG( =CH-2- CAHTUNGTRENNUNG( 2-PrO)-
C H )] (4), and their activity in various
6
4
metathesis reactions are described.
Compounds 1–4 were prepared by re-
action of the parent complexes [RuCl2
and 2 yielded poly AHCTUNETGRNNUN(G COD) with a trans-
Keywords: alkenes · homogeneous
catalysis · metathesis · polymeri-
zation · ruthenium
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(IMesH )
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(=CH-2-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)C H )]
(5)
2
6
4
(
IMesH =1,3-bis-(2,4,6-trimethylphe-
2
nyl)-4,5-dihydroimidazol-2-ylidene)
Introduction
tions in organic and polymer chemistry as well as materials
[1]
[1–5]
[1,6,7]
science. Both Schrock-
and Grubbs-type
catalysts
The development of well-defined transition metal alkyli-
denes paved the road for metathesis into numerous applica-
and initiators have been subject to numerous modifications,
which significantly broadened the range of applications. In
Ru-based Grubbs-type catalysts, variations in the N-hetero-
[8–23]
cyclic carbene
zylidene) ligand
(NHC) as well as in the alkylidene (ben-
have been reported. Furthermore, the
[24–44]
[
a] P. S. Kumar, Prof. Dr. M. R. Buchmeiser
Leibniz-Institut fꢀr Oberflꢁchenmodifizierung e.V. (IOM)
Permoserstr. 15,D-04318 Leipzig (Germany)
Fax : (+49)341-235-2584
replacement of the chloride ligands by triflate, various car-
[45–55]
boxylates, and phenoxides has been described,
a con-
cept that has also been used for catalyst immobilization pur-
E-mail: michael.buchmeiser@iom-leipzig.de
[56]
poses. So far, the bis(perfluorocarboxylate)-derivatives of
the second generation Grubbs- and Grubbs–Hoveyda cata-
[
b] Dr. K. Wurst
Institut fꢀr Allgemeine, Anorganische und Theoretische Chemie
Universitꢁt Innsbruck
Innrain 52a, A-6020 Innsbruck (Austria)
lysts are the only Ru–alkylidenes that allow for the cyclopo-
[46,48,49]
lymerization of 1,6-heptadiynes,
a task that may other-
[
c] Prof. Dr. M. R. Buchmeiser
Institut fꢀr Technische Chemie
Universitꢁt Leipzig
wise only be accomplished in a controlled or even living
[57–65]
manner by particularly designed Schrock catalysts.
There are only few reports on Ru-isocyanates and isothio-
cyanates. Nagao et al. synthesized a series of polypyridine
Linnꢂstr. 3,D-04103 Leipzig (Germany)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.200900099.
[66]
ruthenium (II) isocyanates and isothiocyanates.
Werner
Chem. Asian J. 2009, 4, 1275 – 1283
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1275

FULL PAPERS
IV
et al. reported a number of Ru mono- and di(isocyanato)
Results and Discussion
allenylidenes and alkylidenes of the general formula
RuXX’ ACHTUNGTRENNUNG( PR ) ACHTUNGTRENNUNG( CHR) and RuXX’ ACHTUNGERTNNUGN( PR ) AHCTUNGTNERNG(U C=CHR) (X=Cl,
3 2 3 2
Synthesis and Structure of Complexes 1–4
N=C=O; X’=C=C=O). However, no attempts to use these
Complexes 1 and 3 were prepared by chloride metathesis
compounds in any metathesis-based reactions have been un-
from the second generation Grubbs–Hoveyda catalyst RuCl2
[67]
[68]
dertaken so far. Herein, we report the extension of the
concept of pseudo-halide derivatives of Grubbsꢄ catalyst and
describe the synthesis and metathetical activity of well-de-
fined isocyanate-, and isothiocyanate-derived second genera-
tion Grubbs–Hoveyda catalysts.
A
H
U
G
R
N
U
(IMesH )
A
H
U
G
R
N
U
G
A
H
U
G
E
N
N
(2-PrO)-C H ) (5).
Thus, reaction of 5
2
6
4
with silver cyanate and thiocyanate, respectively, allowed for
the synthesis of 1 and 3 as dark green and dark yellow-
green solids in 84 and 78% yield (Scheme 1). Complexes 2
and 4 were prepared in an analogous way from RuCl (1,3-
2
Abstract in German: Wir berichten ꢀber die Synthese und
Charakterisierung von Isocyanat- und Isothiocyanat basier-
ten Grubbs–Hoveyda-Typ Rutheniumalkylidenkomplexen
der 2. Generation, d. h. ꢀber [Ru
ACHTUNGTRENNU(GN N=C=O) ACHTUNGTRENNUNG( IMesH ) ACHUTNGRENNUG( =CH-
2 2
2
-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)-C H )] (1), [Ru(N=C=O) (1,3-dimesityl-3,4,5,6-
ACHTUNGTRENNUNG
6
4
2
tetrahydropyrimidin-2-yliden)
Ru(N=C=S) (IMesH )(=CH-2-
(N=C=S) (1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-
A
H
U
G
R
N
N
A
H
U
G
R
N
U
G
(2),
6
4
Scheme 1. Synthesis of catalysts 1–4.
[
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
A
H
N
T
E
N
N
ACHTUNGTRENNUNG
2
2
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
dimesityltetrahydropyrimidin-2-ylidene)
A
H
U
G
R
N
U
G
ACHTUNGTRENUNNG( 2-PrO)-
2
[13]
yliden)
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(=CH-2-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)-C H )] (4) und deren Aktivitꢁt in
C H ) (6),
6 3
6
4
verschiedenen Metathesereaktionen. Die Verbindungen 1–4
wurden mittels Reaktion der Startkomplexe [RuCl2
yellow-green amorphous powders in 83 and 75% yield, re-
spectively. In the H NMR spectrum, complexes 1–4 were
1
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(IMesH )
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(=CH-2-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)C H )] (5) (IMesH =1,3-Bis(2,4,6-
characterized by an upfield shift of the alkylidene proton
signal (16.37 ppm (1) and 16.40 (ppm) (3) as well as
16.08 ppm (2) and 16.02 ppm (4)), as compared to the alkyli-
2
6
4
2
trimethylphenyl)-4,5-dihydroimidazol-2-yliden)
RuCl (1,3-Dimesityl-3,4,5,6-tetrahydropyrimidin-2-yliden)-
und
[
2
[68]
[13]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(=CH-2-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)-C H )] (6) mit Silbercyanat bzw. Silberthio-
dene signal of parent 5 (16.56 ppm) and 6 (16.48 ppm).
6
4
1
3
cyanat hergestellt. Die Struktur von Komplex 1 wurde mit-
tels Einkristallrçntgenstrukturanalyse ermittelt und bestꢁ-
tigte die Isocyanat-Bindungsstruktur des Liganden. Die Iso-
thiocyanat Bindungsstruktur in 3 und 4 wurde zweifelsfrei
mittels IR und C NMR Spektroskopie bestimmt. Die Iso-
cyanat-basierten Komplexe 1 und 2 erwiesen sich als exzel-
lente Katalysatoren fꢀr die Ring çffnende Metathesepoly-
merisation (ROMP) von cis-Cycloocta-1,5-dien (COD).
Sowohl Komplex 1 als auch Komplex 2 erlaubten die Syn-
In the C NMR, the signals for the isocyanate carbon of 1
and 2 were found at d=134.6 and 133.7 ppm, the signals for
the isothiocyanate carbon of 3 and 4 were found at d=132.5
and 133.4 ppm, respectively. No additional signals around
110 ppm, which would be indicative for cyanate or thiocya-
nate formation, were observed. To further distinguish be-
13
tween iso ACHUTNRGNENUG( thio)cyanate and (thio)cyanate coordination, we
first recorded the IR-spectra of 1–4. These were in accord-
ance with those of other Ru-isocyanate and isothiocyanate
[
66]
these von poly
8
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(COD) mit einem hohen trans-Anteil von ca.
complexes. Thus, the values for the n band for 1–4 were
CN
À1
0%. Eine Polymerisationskinetik erster Ordnung mit uner-
2216, 2225, 2083, and 2088 cm (Figures S5–S8 in the Sup-
À1
wartet hohen Reaktionsraten (k =0.068 bzw. 0.26 s )
wurden beobachtet. Die Komplexe 3 und 4 waren ebenfalls
aktive Initiatoren fꢀr ROMP von COD, allerdings resul-
porting Information). However, in order to provide unam-
p
À
biguous proof for the mode of coordination of the SCN
À
and OCN ligands, we additionally confirmed the structure
tierte daraus poly
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(COD) mit einem hohen cis-Anteil von 80
of 1 by X-ray analysis (Figure 1). Crystals of 1, suitable for
X-ray analysis, were obtained via the layering of n-hexane
over a concentrated dichloromethane solution of 1, produc-
ing dark green needle-type crystals. Compound 1 crystallizes
in the monoclinic space group C2/c, a=2302.05(3), b=
3442.93(8), c=930.01(8) pm, a=g=908, b=109.952(2)8, Z=
8.
bzw. 67%. Die Komplexe 1 und 2 zeigten auch eine gute ka-
talytische Aktivitꢁt in der Kreuzmetathese (CM).
Schließlich erwiesen sich die Komplexe 1–4 auch als exzel-
lente Katalysatoren fꢀr die regioselektive Cyclopolymerisa-
tion von Diethyl-2,2-dipropargylmalonat (DEDPM). In
allen Fꢁllen wurde Poly ACHUTNGRNEUNG( DEDPM) erhalten, welches auss-
chließlich aus 5-gliedrigen Repetiereinheiten, d.h. Cyclo-
pent-1-ene-1,2-vinylenen besteht.
The distance Ru(1)ÀC(16), that is, the bond length of the
Ru-alkylidene, is 180.8(4) pm, and thus differs only slightly
IV
from that observed in the related Ru -alkylidene pseudoha-
1276
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ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 1275 – 1283

IV
Isocyanate- and Isothiocyanate-Derived Ru -Based Alkylidenes
Figure 1. X-ray structure of 1. Selected bond lengths (pm): Ru(1)–C(16),
1
2
80.8(4); Ru(1)–C(1) 196.7(3); Ru(1)–N(3) 202.2(4); Ru(1)–N(4)
00.8(4); Ru(1)–O(1) 225.6(2). Selected bond angles (8): C(16)-Ru(1)-
N(4) 96.55(16); C(16)-Ru(1)-N(3) 100.47(16); C(16)-Ru(1)-C(1),
01.75(16); C(1)-Ru(1)-N(4), 91.84(14); C(1)-Ru(1)-N(3), 93.56(13),
1
N(4)-Ru(1)-N(3), 160.68(14); C(16)-Ru(1)-O(1), 79.38(14); C(1)-Ru(1)-
O(1), 177.30(12); N(4)-Ru(1)-O(1), 85.59(11); N(3)-Ru(1)-O(1),
8
8.62(11).
lide complex Ru
7, Ru(1)-C(16)=182.6(2) pm). The same is true for the
distances Ru(1)-C(1) (196.7(3) pm) and Ru(1)-O(1)
225.6(2) pm), which are 197.9(2) and 224.58(15) pm, respec-
ACHTUNGTRENNUNG( CF COO) ACHTUNGRTNENU(G IMesH ) AHCTUNGTRENNNGU( CH-2- ACHUTNGTRNNEU(G 2-PrO)-C H )
3 2 2 6 4
[48]
(
(
[48]
tively, in 7. However, very similar values are also found in
the parent complex 5.
[68]
These data clearly illustrate that
any attempt to predict the catalytic reactivity of a catalyst
solely from its structural data may not always be successful.
Figure 2. a) Kinetics of ROMP of COD by the action of 1–4. b) First-
order plots for 1 and 2 in the ROMP of COD. [initiator]=1.8 mm,
Ring-Opening Metathesis Polymerization (ROMP) of
cis-1,5-Cyclooctadiene (COD) by the Action of 1–4
[
COD]=1.8m.
In order to benchmark the existing systems according to a
set of experiments and reaction conditions that has been
suggested for the characterization of new metathesis cata-
lysts, we first checked for the catalytic activities of com-
plexes 1–4 in ROMP using cis-1,5-cyclooctadiene (COD) as
a monomer. The isocyanate-derived complexes 1 and 2
showed excellent reactivity in the ROMP of this monomer
showed a comparable moderate reactivity in the ROMP of
COD. Applying the same conditions, complete conversion
of the monomer (200 equivalents with respect to 3 or 4) was
[69]
observed within 7 h. The number average molecular weights
À1
(M ) were 45500 and 59200 gmol with PDIs of 2.17 and
n
(
Figure 2a). Thus, at room temperature the reaction was
1.89, respectively. Interestingly, poly AHCTUNTGERNNUNG( COD) that formed by
completed within 30 seconds by the action of 0.1 mol% of 1
and 2 with respect to COD. Applying first-order kinetics
the action of 3 or 4 displayed a cis/trans ratio of 4:1 and 2:1,
respectively (Figures S3 and S4 in the Supporting Informa-
tion). We are unable to explain these differences in the cis/
trans ratio at the current time.
(
Figure 2b), the rate constants of polymerization (k ) are
p
À1
0.068 and 0.26 s , respectively. The catalytic activities of
complexes 1 and 2 are thus comparable to those of the re-
cently reported catalyst RuCl (1,3-dimesityl-4,5,6,7-tetrahy-
2
Ring-Closing Metathesis (RCM) by the Action of 1–4
dro-1,3-diazepin-2-ylidene) ACTHUNGTERNNNU(G =CH-2- CAHTUNGTRNENUNG( 2-PrO)C H ), which is
6 4
[70]
based on a 7-membered NHC. As compared to the theo-
The catalytic activity of complexes 1–4 in various RCM re-
actions using diethyl 2,2-diallylmalonate (DEDAM), diethyl
2-allyl-2-methallylmalonate, and diethyl 2,2-dimethallylmal-
onate was investigated. Monomer conversion was monitored
by GC-MS. Surprisingly, complexes 1 and 2 (both used at a
0.1 mol% level), which were found to be highly active in
ROMP (see above), were totally inactive in the RCM of the
above-mentioned dienes. In contrast to that, we found very
moderate activity in the RCM of the above-mentioned sub-
retical value derived from the COD/initiator ratio
À1
(
Mn (theor) =22000 gmol ), the number average molecular
weights (M ) for poly ACHUTNGRNEGUN( COD) prepared by the action of 1
n
À1
and 2 were 20300 and 51900 gmol with polydispersity in-
dices (PDIs) of 2.05 and 1.90, respectively. The poly(COD)
AHCTUNGTRENNUNG
that formed by the action of both 1 and 2 displayed a cis/
trans ratio of 1:4 (Figures S1 and S2 in the Supporting Infor-
mation). In contrast, the isothiocyanate complexes 3 and 4
Chem. Asian J. 2009, 4, 1275 – 1283
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1277

M. R. Buchmeiser et al.
FULL PAPERS
strates with 3 and 4 (both used at a 1 mol% level). Conver-
sion of DEDAM reached only 30 and 1%, respectively, by
the action of 3 and 4 within 90 min. Complexes 1, 2, and 4
did not show any significant reactivity in the RCM of diethyl
2
1
-allyl-2-methallylmalonate. With 3, a conversion of only
2% was achieved in the RCM of diethyl 2-allyl-2-methal-
lylmalonate within 2 h. Consequently, no significant activity
at all was observed in the RCM of diethyl bis(methallyl)
malonate. A summary of the results in RCM is given in
Table 1.
Cross-Metathesis (CM) Reactions by the Action of 1–4
Complexes 1 and 2 were found to be good catalysts for the
CM of allylbenzene with cis-1,4-diacetoxy-2-butene
(
7
Figure 3). Substrate conversion to the desired product was
2% within 20 min by the action of 1 and 68% within the
Figure 3. CM of allylbenzene with cis-1,4-diacetoxy-2-butene by the
action of 1–4. [initiator]=0.5 mm, [allylbenzene]=0.2m, [cis-1,4-diace-
toxy-2-butene]=0.4m.
same time by the action of 2 (both at a 2.5 mol% level). In
the CM of methyl acrylate with 5-hexenyl acetate, however,
96 and 65% conversion to methyl-4-acetoxyhex-2-enoate
thiocyanate-derived initiators 1–4 showed good reactivity in
was achieved with 1 and 2 within two hours (Figure 4). In
contrast to 1 and 2, the isothiocyanate-derived complexes 3
and 4 showed only 1% yield in the CM between allylben-
zene and cis-1,4-diacetoxy-2-butene within 60 min
the cyclopolymerization of DEDPM. The isolated yields
were 80, 97, 98, and 78%, respectively, for poly ACHNTUGRNENUG( DEDPM)
synthesized by the action of 1–4 (Table 1).
The reactivity of 1–4 in the cyclopolymerization reaction
is comparable to that of other bis(trifluoroacetate)-modified
second generation Grubbs–Hoveyda-type ruthenium initia-
tors. In terms of polymer structure, all cyclopolymerizations
(
Figure 3), 30% and 1% conversion, respectively, were ob-
served in the CM of methyl acrylate with 5-hexenyl acetate
(
Figure 4).
[71,72]
proceeded selectively by a-insertion
and the resulting
poly(DEDPM) was based on greater than 98% five-mem-
bered repeat units, that is, on cyclopent-1-ene-1,2-vinylenes
AHCTUNGTRENNUNG
Cyclopolymerization of DEDPM by the Action of 1–4
Finally, we studied the catalytic activity of complexes 1–4
for the cyclopolymerization of diethyl dipropargyl malonate
(Figure 5). The results obtained with 1–4 thus fit the recent-
ly proposed mechanism for the Ru -alkylidene triggered cy-
IV
(
DEDPM) (Scheme 2). Both the isocyanate- and the iso-
clopolymerization of 1,6-heptadiynes, which suggests a trans-
orientation of the intermediary
ruthenacyclobutenes, prevent-
Table 1. Summary of the results for ROMP, RCM, CM, and cyclopolymerization by the action of 1–4.
substrate
catalyst [mol%]
yield [%]
TON ing the formation of six-mem-
[
[
[
[
a]
a]
a]
a]
[50]
COD
COD
COD
COD
DEDAM
DEDAM
DEDAM
DEDAM
1 (0.1)
2 (0.1)
3 (0.1)
4 (0.1)
1 (1)
2 (1)
3 (1)
4 (1)
1 (1)
99
99
95
98
990
990
950
980
0
0
30
1
0
0
12
0
bered repeat units.
A more detailed investigation
of the reaction kinetics revealed
that the activity in cyclopolyme-
rization decreased in the order
3~2>1>4 (Figure 6a) This is
in sharp contrast to the order of
reactivity found in the ROMP
of COD, which is 2>1>4>3,
or in CM, where the order was
[
b]
0
0
[
b]
[
b]
30
[
[
[
b]
b]
b]
1
0
0
diethyl 2-allyl-2-methallylmalonate
diethyl 2-allyl-2-methallylmalonate
diethyl 2-allyl-2-methallylmalonate
diethyl 2-allyl-2-methallylmalonate
allyl benzene/1,4-diacetoxy-cis-2-butene
allyl benzene/1,4-diacetoxy-cis-2-butene
allyl benzene/1,4-diacetoxy-cis-2-butene
allyl benzene/1,4-diacetoxy-cis-2-butene
methyl acrylate/5-hexenyl acetate
methyl acrylate/5-hexenyl acetate
methyl acrylate/5-hexenyl acetate
methyl acrylate/5-hexenyl acetate
DEDPM
2 (1)
3 (1)
4 (1)
[
b]
12
[
b]
0
[
[
b]
1 (2.5)
2 (2.5)
3 (2.5)
4 (2.5)
1 (2.5)
2 (2.5)
3 (2.5)
4 (2.5)
1 (1)
72
68
29
27
0.4
0.4
39
26
12
0.4
80
97
98
78
1
>2>3>4. Plots of ln ACHTUNGTRENNUNG( c /c )
0 t
b]
versus time (Figure 6b) re-
vealed that the polymerization
of DEDPM by either 1 or 4 fol-
lowed roughly first-order kinet-
ics while the one initiated by 2
or 3 did not. However, the plots
for initiators 1 and 4 also dis-
played some sigmoidal shape.
The higher control in cyclopoly-
merization achieved by 1 and 4
[
b]
1
1
[
b]
[
[
[
b]
99
65
30
b]
b]
[
b]
1
[
[
[
[
a]
80
97
98
78
a]
a]
a]
DEDPM
DEDPM
DEDPM
2 (1)
3 (1)
4 (1)
[
a] yield of isolated product, [b] by GC-MS.
1278
www.chemasianj.org
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 1275 – 1283

IV
Isocyanate- and Isothiocyanate-Derived Ru -Based Alkylidenes
action of 3 or 4 displayed much
lower molecular weights than
anticipated (using a DEDPM/
initiator ratio of 200:1, the the-
oretical value for M
is
n(theor.)
À1
4
7400 gmol ). In combination
with the high PDIs, the low mo-
lecular weights of poly-
ACHTUNGERTN(NUNG DEDPM) prepared by the
Scheme 2. Regioselective cyclopolymerization of DEDPM by the action of 1–4. [initiator]=1.8 mm,
[
DEDPM]=0.18m.
action of 2–4 are indicative of
substantial back-biting and/or chain transfer during the poly-
merization.
Conclusions
A series of isocyanate- and isothiocyanate-derived rutheni-
um (IV) NHC alkylidene complexes have been successfully
synthesized and their catalytic activity has been determined
for selected metathesis reactions. The new compounds
showed excellent reactivity in the ROMP of COD and good
reactivity in various CM reactions, however, their activity in
RCM was comparatively poor. All four novel catalysts and
initiators performed differently depending on the type of
metathesis reaction. While the novel systems certainly add
IV
to the existing armor of Ru -alkylidenes with particular
strengths for selected applications, particular attention must
be devoted to the questions about the origin of high or low
activity of certain Ru-based metathesis catalysts/initiator in
a particular metathesis reaction. Similarly, the specific differ-
ences in the cis/trans ratio in ROMP-derived polymers need
to be addressed.
Figure 4. CM of methyl acrylate with 5-hexenyl acetate by the action of
–4. [initiator]=4.3 mm, [5-hexenyl acetate]=[methyl acrylate]=0.18m.
1
was also reflected by the values for M and the PDI. Using
n
a ratio of DEDPM/1–4 of 1:200, polymers with M =
Experimental Section
n
À1
À1
À1
7
1
5800 gmol ,
40500 gmol ,
13500 gmol ,
and
2
General: All manipulations were performed under a N atmosphere in a
glove box (LabMaster 130, MBraun, Garching, Germany) or by standard
Schlenk techniques unless specified otherwise. Propargyl bromide
À1
2400 gmol with PDIs of 1.33, 2.45, 2.66, and 2.09 were
obtained. Particularly, poly ACHTUNGRNENUG( DEDPM) prepared by the
1
3
3 3
Figure 5. C NMR spectra of poly ACHTUNGTERNN(NUG DEDPM) in CDCl ; (* denotes CDCl ).
Chem. Asian J. 2009, 4, 1275 – 1283
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1279

M. R. Buchmeiser et al.
FULL PAPERS
an AOC-20i Autosampler, using an SPB fused silica (Rxi-5MS) column
(
30 mꢆ0.25 mmꢆ0.25 mm film thickness) and on a Shimadzu GCMS-
QP2010S equipped with an AOC-20i Autosampler using an SPB fused
silica (Rxi-5MS) column (30 mꢆ0.25 mmꢆ0.25 mm film thickness), re-
spectively. The injection temperature was 1508C, the initial column tem-
perature was 708C. It was then increased to 1218C within 7 min. Diethyl
[
73]
2
,2-dipropargylmalonate (DEDPM),
diethyl 2-allyl-2 methallylmalo-
[
74]
[74]
nate diethyl 2,2-dimethallylmalonate as well as [RuCl
,4,5,6-tetrahydropyrimidin-2-ylidene)(=CH-2-(2-PrO)-C
2
(1,3-dimesityl-
[13]
3
A
H
U
G
R
N
U
G
A
H
U
G
R
N
N
6
H
4
)]
were
prepared according to published procedures and checked for purity by
HRMS-, NMR-, and IR-spectroscopy. GPC measurements were per-
formed on an LC10 AD liquid chromatograph equipped with an SIL-10
ADVP auto injector, a CTO-10AC column oven, an SCL-10AVP system
controller and an RID-10A refractive index detector (all from Shimad-
zu). A precolumn and three consecutive Plgel 5 mm MiniMIX-c columns
(
7.5ꢆ300 mm, Polymer Laboratories, Varian) were operated in CHCl
3
À1
applying a flow rate of 0.3 mLmin . Molecular weights were determined
by calibration with poly
Ru(N=C=O) (IMesH
CH-2-(2-PrO)-C )] (600 mg, 0.95 mmol) was dissolved in CH
5 mL). slightly turbid solution of AgOCN (2 equiv, 288 mg,
ACHTUNGTRENNUNG
[
A
H
U
G
R
N
N
2
A
H
U
G
R
N
U
G
2
)
A
H
N
T
E
N
G
A
T
N
T
E
N
G
6
H
4
)] (1): [RuCl
2
A
H
U
G
R
N
U
G
2
)
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(=
A
H
U
G
R
N
N
6
H
4
2
Cl
2
(
A
1
6
.95 mmol) in DMF (2 mL) was added slowly. Stirring was continued for
0 min and the formation of a precipitate was observed. The AgCl was
filtered off and the solution was evaporated to dryness. The residue was
redissolved in CH Cl2, the solution was flashed over a pad of silica gel
2 cm) and then evaporated to dryness, yielding 1 as a dark green solid.
2
(
Pure product was obtained by crystallization from n-hexane, affording
dark green needles in 84% yield (520 mg, 0.82 mmol), which were also
1
found suitable for X-ray analysis. H NMR (600.25 MHz, CDCl3, 258C):
3
d=16.37 (s, 1H; Ru=CHAr), 7.50 (t, J (H,H)=7.80 Hz, 1H; aromatic
3
CH), 7.11 (s, 4H; mesityl aromatic CH), 6.92 (t, J (H,H)=7.20 Hz, 1H;
3
3
aromatic CH), 6.83 (d, J (H,H)=7.20 Hz, 1H; aromatic CH), 6.79 (d, J
(
3
H,H)=8.40 Hz, 1H; aromatic CH), 4.84 (sept, J (H,H)=6.60 Hz, 1H;
CH CHOAr), 4.16 (s, 4H; N(CH N), 2.42 (s, 18H; mesityl o- and p-
), 1.09 ppm (d, J (H,H)=6.10 Hz, 6H; (CH
150.95 MHz, CDCl3, 258C): d=299.7, 210.2, 152.5, 144.1, 139.4, 138.9,
(
3
)
2
A
H
U
G
R
N
U
G
2 2
)
3
13
CH
3
3 2
) CHOAr); C NMR
(
1
34.6, 130.1, 129.7, 122.8, 122.6, 112.6, 74.6, 51.5, 21.2, 20.6, 18.4 ppm; IR
(
(
ATR mode): u~ =3550 (w), 2918 (m), 2361 (m), 2216 (vs), 1589 (m), 1574
s), 1484 (m), 1453 (w), 1401 (w), 1376 (w), 1335 (w), 1264 (vs), 1215 (m),
À1
1
155 (m), 1112 (m), 1035 (m), 937 (m), 852 (m), 806 (m), 778 cm (m);
+
.
HRMS (ESI): calcd. for C33
38 4 3
H N O Ru: 640.1987, found: 640.2306 [M ]
(
28.7%).
Ru(N=C=O)
(2-PrO)-C
mesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)
[
2-
A
H
U
G
R
N
U
G
2
(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)
)] (2): This compound was prepared from [RuCl (1,3-di-
(=CH-2-(2-PrO)-C
ACHTUNGTRENNUNG( =CH-
Figure 6. Kinetics of the cyclopolymerization of DEDPM by the action of
A
H
N
T
E
N
N
6
H
4
2
[
13]
1
–4. a) conversion versus time, b) First order plot. [initiator]=4.2 mm,
A
H
U
G
R
N
N
A
H
U
T
E
N
N
6 4
H )]
[
DEDPM]=0.42m.
(325 mg, 0.51 mmol) and AgOCN (165 mg, 1.1 mmol) following the pro-
cedure described for 1. The product was isolated as a light green powder
1
in 83% yield (280 mg, 0.42 mmol). H NMR (600.25 MHz, CDCl3, 258C):
3
d=16.08 (s, 1H; Ru=CHAr), 7.49 (t, J (H,H)=7.80 Hz, 1H; aromatic
3
CH), 7.11 (s, 4H; mesityl aromatic CH), 6.88 (t, J (H,H)=7.20 Hz, 1H;
aromatic CH), 6.80 (d, J (H,H)=7.20 Hz, 1H; aromatic CH), 6.71 (d, J
(
80 wt.% solution in toluene), chloroform, acetonitrile, cis-1,5-cycloocta-
diene (COD), CDCl , and CD Cl were distilled from CaH under argon
and stored over molecular sieves (4 ꢅ). Allylbenzene and cis-1,4-diace-
toxy-2-butene were distilled from anhydrous K CO and stored over mo-
lecular sieves (4 ꢅ). 5-Hexenyl acetate was distilled and stored under di-
nitrogen. n-Hexane was distilled from sodium-benzophenone under N
Reagent grade DMF was dried over CaH and stored over molecular
sieves (4 ꢅ). Diethyl ether, CH Cl , THF, toluene, and pentane were
3
3
3
2
2
2
3
(
(
H,H)=8.40 Hz, 1H; aromatic CH), 4.68 (sept, J (H,H)=6.00 Hz, 1H;
3
CH
)N), 2.35, 2.49, 2.55 (3ꢆs, 12H; mesityl o-CH
N(CH -CH -CH )N), 2.25 (s, 6H; mesityl p-CH ), 0.91 ppm (d,
H,H)=6.10 Hz, 6H; (CH CHOAr); C NMR (150.95 MHz, CDCl3,
3
)
2
CHOAr), 3.55, 3.60 (t,
J
(H,H)=6.01 Hz, 4H; N(CH
2 2
-CH -
2
3
CH
2
3
), 2.32 (brs, 2H;
3
2
2
2
3
J
2
.
13
(
3 2
)
2
258C): d=303.9, 201.9, 151.8, 145.1, 144.2, 141.6, 140.2, 138.5, 136.8,
135.5, 133.7, 130.2, 130.1, 129.8, 122.8, 122.7, 112.5, 74.1, 49.8, 49.5, 21.6,
2
1.2, 21.1, 20.7, 19.6, 17.8 ppm; IR (ATR mode): u~ =3546 (w), 2980 (w),
2922 (w), 2361 (m), 2342 (m), 2225 (vs), 2054 (w), 1947 (w), 1669 (w),
1608 (w), 1591 (m), 1576 (m), 1493 (s), 1453 (m), 1379 (m), 1312 (m),
2
2
dried by an SPS solvent purification system (MBraun, Garching, Germa-
ny). Purchased starting materials and other chemicals or reagents were
used without further purification.
II+
NMR spectra were recorded on a Bruker Avance
600 and Bruker
1290 (s), 1262 (w), 1240 (w), 1208 (s), 1159 (w), 1115 (s), 1037 (m), 940
À1
Spectrospin 250 spectrometer, respectively, in the indicated solvent at
58C and are listed in parts per million downfield from tetramethylsilane
(m), 918 (w), 882 (w), 854 (w), 808 (w), 751 (vs), 671 cm (w); HRMS
+
2
(ESI) calcd. for C34
[Ru(N=C=S) (IMesH )
CH-2-
H
40
N
4
O
3
Ru: 654.2144, found: 654.2472 [M ] (36.6%).
as an internal standard for proton and carbon. FT-IR spectra were re-
corded on a Bruker Vector22 spectrometer using ATR technology. UV/
Vis spectra were recorded on a UV-21IPC spectrometer. GC-MS investi-
gations were carried out on a Shimadzu GCMS-QP5050 equipped with
A
H
U
G
R
N
U
G
A
H
U
G
R
N
U
G
2 6 4 2
ACHTUNGTERN(UNGN =CH-2- ACHUTNGRTNENGU( 2-PrO)-C H )] (3): [RuCl2 ACHTUNGTRNEG(UN IMesH ) ACHTUNGTRENNUNG( =
2
A
H
U
G
R
N
U
G
6
4
2
(5 mL). A slightly turbid solution of AgSCN (2 equiv, 81 mg, 0.48 mmol)
in DMF (2 mL) was slowly added. Stirring was continued for 60 min and
1280
www.chemasianj.org
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 1275 – 1283

IV
Isocyanate- and Isothiocyanate-Derived Ru -Based Alkylidenes
the formation of a precipitate was observed. The AgCl was filtered off
and the solution was evaporated to dryness. The residue was redissolved
to poly
45500 gmol , PDI=2.17.
Poly(COD) [cis/trans~2:1], prepared by the action of 4: H, C NMR
and IR spectra were identical to poly(COD) prepared by the action of 3.
n
ACHTUNGTNERNUN(G COD) prepared by the action of 1. Isolated yield: 95%, M =
À1
in CH
2
Cl
2
, the solution was flashed over a pad of silica gel (2 cm) and
1
13
AHCTUNGTRENNUNG
then evaporated to dryness, yielding 3 as a light yellow green solid. The
product was obtained by washing the material with dry pentane, which
afforded a yellow-green powder in 78% yield (125 mg, 0.18 mmol).
AHCTUNGTRENNUNG
À1
n
Isolated yield: 98%, M =59200 gmol , PDI=1.89.
RCM of diethyl 2,2-diallylmalonate by the action of 1–4. Complex 1
1
H NMR (600.25 MHz, CDCl3, 258C): d=16.40 (s, 1H; Ru=CHAr), 7.60
À6
À6
(
1
1
2.72 mg, 4.16ꢆ10 mol, 1.0 mol%),
2
(2.72 mg, 4.16ꢆ10 mol,
3
(
t, J (H,H)=7.80 Hz, 1H; aromatic CH), 7.14 (s, 4H; mesityl aromatic
À6
.0 mol%), 3 (2.79 mg, 4.16ꢆ10 mol, 1.0 mol%) or 4 (2.85 mg, 4.16ꢆ
3
3
CH), 6.96 (t, J (H,H)=7.20 Hz, 1H; aromatic CH), 6.84 (d, J (H,H)=
8
CH), 4.90 (sept, J (H,H)=6.00 Hz, 1H, (CH
À6
0
mol, 1.0 mol%), dissolved in 0.5 mL of CH
2
Cl
2
, was added to
3
.40 Hz, 1H; aromatic CH), 6.80 (d, J (H,H)=7.20 Hz, 1H; aromatic
À4
DEDAM (100 mg, 4.16ꢆ10 mol, 0.11 mL), dissolved in the same
amount of the same solvent. tert-Butyl benzene (65 mL) was used an in-
ternal standard. The reaction was carried out at 358C under an Ar atmos-
phere. Conversion of the monomer was monitored by GC-MS.
3
3 2
) CHOAr), 4.20 (s, 4H; N-
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(CH N), 2.43 (s, 18H; mesityl o- and p-CH
2
)
2
3
), 1.08 ppm (d, J (H,H)=
1
3
6
3
1
.00 Hz, 6H; (CH ) CHOAr); C NMR (150.95 MHz, CDCl3, 258C): d=
3 2
11.8, 206.5, 153.4, 146.9, 144.2, 139.9, 138.6, 132.5, 129.9, 123.5, 123.1,
12.9, 75.5, 51.6, 21.2, 20.5, 18.4 ppm; IR (ATR mode): u~ =2976 (w), 2918
Ring-closing metathesis (RCM) of diethyl 2-allyl-2-methallylmalonate by
À6
the action of 1–4. Complex 1 (2.51 mg, 3.93ꢆ10 mol, 1.0 mol%), 2
(
(
m), 2359 (m), 2341 (m), 2142 (m), 2083 (vs), 1607 (m), 1589 (m), 1485
s), 1453 (m), 1407 (w), 1377 (w), 1316 (w), 1289 (s), 1267 (m), 1231 (w),
À6
À6
(
1
2.57 mg, 3.93ꢆ10 mol, 1.0 mol%),
3
(2.64 mg, 3.93ꢆ10 mol,
À6
.0 mol%), or 4 (2.71 mg, 3.93ꢆ10 mol, 1.0 mol%), dissolved in 0.5 mL
1
157 (w), 1135 (w), 1113 (w), 1097 (w), 1034 (w), 935 (m), 912 (m), 851
À4
of CH
2
Cl
2
, was added to substrate (100 mg, 3.9ꢆ10 mol), dissolved in
À1
(
w), 817 (w), 749 cm (w); HRMS (ESI) calcd. for C32
H
38
N
4
OS
2
Ru:
the same amount of the same solvent. tert-Butyl benzene (65 mL) was
used an internal standard. The reaction was carried out at 358C under an
Ar atmosphere. Conversion of the monomer was monitored by GC-MS.
+
6
72.1531, found: 614.1784 [MÀNCS] (50%).
[
Ru
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(N=C=S)
2
(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)ACHTUTGNENRNUG
2
-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(2-PrO)-C
6
H
4
)] (4): Complex 4 was prepared from [RuCl
(=CH-2-(2-PrO)-C
2
Ring-closing metathesis (RCM) of diethyl 2,2-dimethallylmalonate by
[
13]
tyl-3,4,5,6-tetrahydropyrimidin-2-ylidene)
A
H
U
G
R
N
U
G
A
H
U
G
R
N
U
G
6
H
4
)]
À6
the action of 1–4. Complex 1 (2.38 mg, 3.72ꢆ10 mol, 1.0 mol%), 2
(
311 mg, 0.48 mmol) and AgSCN (164 mg, 0.98 mmol) following the
À6
À6
(
1
2.43 mg, 3.72ꢆ10 mol, 1.0 mol%),
3
(2.51 mg, 3.72ꢆ10 mol,
same procedure as described for 3. The product was obtained as a dark
À6
.0 mol%) or 4 (2.55 mg, 3.72ꢆ10 mol, 1.0 mol%), dissolved in 0.5 mL
1
yellow-green powder in 75% yield (252 mg, 0.36 mmol). H NMR
À4
of CH
2
Cl
2
, was added to the substrate (100 mg, 3.72ꢆ10 mol), dissolved
3
(
600.25 MHz, CDCl3, 258C): d=16.02 (s, 1H; Ru=CHAr), 7.59 (t,
J
in the same amount of the same solvent. tert-Butyl benzene (65 mL) was
used an internal standard. The reaction was carried out at 358C under an
Ar atmosphere. Conversion of the monomer was monitored by GC-MS.
(
7
H,H)=7.20 Hz, 1H; aromatic CH), 7.18 (s, 2H; mesityl aromatic CH),
3
.12 (s, 2H; mesityl aromatic CH), 6.92 (t, J (H,H)=7.80 Hz, 1H; aro-
3
3
matic CH), 6.77 (d, J (H,H)=8.40 Hz, 2H; aromatic CH), 4.75 (sept, J
(
3
Cross-metathesis (CM) of allylbenzene with cis-1,4-diacetoxy-2-butene
3 2
H,H)=6.60 Hz, 1H; (CH ) CHOAr), 3.55, 3.61 (t, J (H,H)=5.40 Hz,
À6
by the action of 1–4: Complex 1 (6.71 mg, 1.05ꢆ10 mol, 2.5 mol%), 2
4
2
0
H; N(CH
.31 (brs, 2H; N(CH
.90 ppm (d,
2
-CH
2
-CH
2
)N), 2.37, 2.50, 2.59 (3ꢆs, 12H; mesityl o-CH
-CH -CH )N), 2.26 (s, 6H; mesityl p-CH
(H,H)=6.00 Hz, 6H; (CH
3
3
),
),
À6
À6
(
6.91 mg, 1.05ꢆ10 mol, 2.5 mol%),
3
(7.11 mg, 1.05ꢆ10 mol,
2
2
2
À6
3
13
2.5 mol%), or 4 (7.25 mg, 1.05ꢆ10 mol, 2.5 mol%), dissolved in 1.0 mL
J
3
)
2
CHOAr);
C NMR
of CH
2
Cl
2
, was added to a mixture of allylbenzene (50 mg, 4.23ꢆ
(
150.95 MHz, CDCl3, 258C): d=316.1, 197.9, 153.1, 145.2, 144.8, 143.6,
À4
À4
1
0
mol, 58 mL) and cis-1,4-diacetoxy-2-butene (145 mg, 8.46ꢆ10 mol,
142.1, 141.1, 138.8, 136.7, 133.4, 132.9, 130.2, 129.7, 123.7, 122.9, 112.6,
7
5.1, 49.8, 49.5, 21.4, 21.3, 21.2, 20.6, 19.6, 17.7 ppm; IR (ATR mode): u~ =
2975 (w), 2921 (w), 2858 (w), 2359 (m), 2341 (m), 2088 (vs), 1966 (w),
1667 (w), 1606 (m), 1589 (s), 1574 (m), 1499 (m), 1474 (s), 1452 (m), 1377
2
equiv, 0.13 mL), dissolved in the same amount of the same solvent. tert-
Butyl benzene (70 mL) was used as an internal standard. The reaction
was carried out at 358C under an Ar atmosphere. Conversion of the mo-
nomer was monitored by GC-MS.
(
(
(
m), 1351 (m), 1293 (w), 1258 (s), 1243 (w), 1207 (m), 1157 (m), 1113
Cross-metathesis (CM) of methyl acrylate with 5-hexenyl acetate by the
m), 1096 (m), 1034 (w), 936 (m), 914 (w), 882 (w), 850 (w), 817 (m), 750
À5
À1
action of 1–4: Complex
(11.5 mg, 1.75ꢆ10 mol, 2.5 mol%),
2
1
(11.1 mg, 1.75ꢆ10 mol, 2.5 mol%),
2
m), 732 (s), 668 cm (w); HRMS (ESI) calcd. for C34
40 4 2
H N ORuS :
À5
À5
+
3
(11.7 mg, 1.75ꢆ10 mol,
.5 mol%) or 4 (12.1 mg, 1.75ꢆ10 mol, 2.5 mol%), dissolved in 2.0 mL
6
86.1687, found: 709.1588 [M+Na] (100%).
À5
ROMP of cis-1,5-cyclooctadiene (COD) by the action of 1–4: Complex 1
of CH
2
Cl
2
, was added to a mixture of methyl acrylate (60 mg, 7.1ꢆ
À6
À6
(
0
1
1.18 mg, 1.84ꢆ10 mol, 0.1 mol%),
2
(1.20 mg, 1.84ꢆ10 mol,
À4
À4
1
0
mol, 1 equiv, 63 mL) and 5-hexenyl acetate (100 mg, 7.1ꢆ10 mmol,
À6
.1 mol%), 3 (1.24 mg, 1.84ꢆ10 mol, 0.1 mol%), or 4 (1.26 mg, 1.84ꢆ
mol, 0.1 mol%), dissolved in CH
200 mg, 1.84ꢆ10 mol, 0.22 mL) dissolved in 0.5 mL of CH
1
equiv, 0.11 mL), dissolved in the same amount of the same solvent. tert-
À6
0
2
Cl
2
(0.5 mL), was added to COD
Cl . tert-
Butyl benzene (70 mL) was used as an internal standard. The reaction
was carried out at 358C under an Ar atmosphere. Conversion of the mo-
nomer was monitored by GC-MS.
À3
(
2
2
Butyl benzene (70 mL) was used as an internal standard. The reaction
was carried out at room temperature. Conversion of the monomer was
monitored by GC-MS.
Cyclopolymerization of diethyl 2,2-dipropargylmalonate (DEDPM) by
À6
the action of 1–4: Complex 1 (5.5 mg, 8.46ꢆ10 mol, 1.0 mol%), 2
1
Poly
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(COD) [cis/trans~1:4], prepared by the action of 1: H NMR
À6
À6
(
5.6 mg, 8.46ꢆ10 mol, 1.0 mol%), 3 (5.6 mg, 8.46ꢆ10 mol, 1.0 mol%)
(
(
(
600.25 MHz, CDCl3, 258C): d=5.41 (s, 2H; Holefin, trans-poly-COD), 5.37
À6
or 4 (5.8 mg, 8.46ꢆ10 mol, 1.0 mol%), dissolved in 1 mL of CH
added to DEDPM (200 mg, 8.46ꢆ10 mol) dissolved in the same
amount of the same solvent ion. The mixture was stirred for 12 h at
2
Cl
2
was
brs, 2H; Holefin, cis-poly-COD), 2.08 (brs, 4H; cis-poly-COD), 2.03 ppm
À4
1
3
s, 4H; trans-poly-COD); C NMR (150.95 MHz, CDCl3, 258C): d=
30.1 (Colefin, trans-poly-COD), 129.5 (Colefin, cis-poly-COD), 32.8 ((CH
trans-poly-COD), 27.5 ppm ((CH 2, cis-poly-COD); IR (ATR mode):
1
2 2,
)
3
58C. Ethyl vinyl ether (0.6 mL) was then added and the mixture was
stirred for another 30 min. The solvent was removed in vacuo, then
0 mL of dry diethyl ether was added. The product was filtered off and
dried in vacuo. The polymer was obtained as a dark-violet powder. Isolat-
2
)
u~ =30003 (w), 2915 (m), 2841 (m), 2359 (w), 2341 (w), 1446 (m), 1352
2
À1
(
w), 1311 (w), 1236 (w), 1054 (w), 963 (vs), 659 cm (m). Isolated yield:
À1
9
9%, M
Poly
and IR spectra were identical to poly
n
=20300 gmol , PDI=2.05.
ed yields were 80, 97, 98 and 78% respectively for poly ACHUTNRGNENUG( DEDPM), syn-
thesized by the action of 1–4.
1
13
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(COD) [cis/trans~1:4], prepared by the action of 2: H, C NMR
A
H
U
G
R
N
U
G
For the recording of the reaction kinetics, complexes 1 (1.3 mg, 2.11ꢆ
À1
Isolated yield: 99%, M
Poly(COD) [cis/trans~4:1], prepared by the action of 3: H NMR
600.25 MHz, CDCl3, 258C): d=5.43 (brs, 2H; Holefin, trans-poly-COD),
.39 (s, 2H; Holefin, cis-poly-COD), 2.09 (s, 4H; cis-poly-COD), 2.04 ppm
n
=51900 gmol , PDI=1.90.
À6
À6
1
0
mol, 1.0 mol%), 2 (1.4 mg, 2.11ꢆ10 mol, 1.0 mol%), 3 (1.4 mg,
1
À6
À6
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2.11ꢆ10 mol, 1.0 mol%), or 4 (1.5 mg, 2.11ꢆ10 mol, 1.0 mol%) dis-
(
5
(
solved in 0.6 mL of CH Cl was added to DEDPM (50 mg, 2.11ꢆ
2
2
À4
10 mol) dissolved in the same amount of the same solvent. tert-Butyl
benzene (60 mL) was used as an internal standard. The reaction was car-
1
3
brs, 4H; trans-poly-COD); The C NMR and IR spectra were identical
Chem. Asian J. 2009, 4, 1275 – 1283
ꢃ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1281

M. R. Buchmeiser et al.
FULL PAPERS
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À4 À1
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p
=1ꢆ10
s
, 2; k
p
(average) =3ꢆ10
s ,
À4 À1
À4 À1
3
; k
p
(average) =4ꢆ10
s
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1
Poly
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U
N
G
T
R
E
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U
N
G
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-CH -C=), 3.46 (q, 4H; CH CH ), 1.39 ppm (t, 6H; CH CH );
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184 (s), 1095 (m), 1010 (m), 947 (w), 897 (w), 860 (m), 736 (m),
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13
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1283