Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: Synthesis, metal immobilization and use in hydroformylation under micellar conditions

Article abstract of DOI:10.3762/bjoc.6.28

Norborn-5-ene-(N,N-dipyrid-2-yl)carbamide (M1) was copolymerized with exo,exo-[2-(3-ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-en-2-carbonyloxy)ethyl] trimethylammonium iodide (M2) using the Schrock catalyst Mo(N-2,6-Me2-C6H3) (CHCMe2Ph)(OCMe(CF3)2)2 [Mo] to yield poly(M1-b-M2). In water, poly(M1-b-M2) forms micelles with a critical micelle-forming concentration (cmc) of 2.8 × 10-6 mol L-1; Reaction of poly(M1-b-M2) with [Rh(COD)Cl]2 (COD = cycloocta-1,5-diene) yields the Rh(I)-loaded block copolymer poly(M1-b-M2)-Rh containing 18 mg of Rh(I)/g of block copolymer with a cmc of 2.2 × 10 ^-6 mol L-1. The Rh-loaded polymer was used for the hydroformylation of 1-octene under micellar conditions. The data obtained were compared to those obtained with a monomeric analogue, i.e. CH3CON(Py)2RhCl(COD) (C1, Py = 2-pyridyl). Using the polymer-supported catalyst under micellar conditions, a significant increase in selectivity, i.e. an increase in the n:iso ratio was accomplished, which could be further enhanced by the addition of excess ligand, e.g., triphenylphosphite. Special features of the micellar catalytic set up are discussed.

Full text of DOI:10.3762/bjoc.6.28

Ring opening metathesis polymerization-derived
block copolymers bearing chelating ligands:
synthesis, metal immobilization and use in
hydroformylation under micellar conditions
Gajanan M. Pawar1, Jochen Weckesser2, Siegfried Blechert*2
and Michael R. Buchmeiser*1
Full Research Paper
Open Access
Address:
Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
1Lehrstuhl für Makromolekulare Stoffe und Faserchemie, Institut für
Polymerchemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550
Stuttgart, Germany; Tel.: +49 (0)711-685-64075; Fax: +49
(0)711-685-64050 and 2Institut für Chemie, Technische Universität
Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
doi:10.3762/bjoc.6.28
Received: 11 January 2010
Accepted: 17 March 2010
Published: 23 March 2010
Email:
Guest Editor: H. Ritter
Siegfried Blechert* - blechert@chemie.tu-berlin.de;
Michael R. Buchmeiser* - michael.buchmeiser@ipoc.uni-stuttgart.de
© 2010 Pawar et al; licensee Beilstein-Institut.
License and terms: see end of document.
* Corresponding author
Keywords:
block copolymers; catalysis; hydrophilic polymers; metathesis;
micelles
Abstract
Norborn-5-ene-(N,N-dipyrid-2-yl)carbamide (M1) was copolymerized with exo,exo-[2-(3-ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-
5-en-2-carbonyloxy)ethyl]trimethylammonium iodide (M2) using the Schrock catalyst Mo(N-2,6-Me2-
C6H3)(CHCMe2Ph)(OCMe(CF3)2)2 [Mo] to yield poly(M1-b-M2). In water, poly(M1-b-M2) forms micelles with a critical
micelle-forming concentration (cmc) of 2.8 × 10−6 mol L−1; Reaction of poly(M1-b-M2) with [Rh(COD)Cl]2 (COD = cycloocta-
1,5-diene) yields the Rh(I)-loaded block copolymer poly(M1-b-M2)-Rh containing 18 mg of Rh(I)/g of block copolymer with a
cmc of 2.2 × 10−6 mol L−1. The Rh-loaded polymer was used for the hydroformylation of 1-octene under micellar conditions. The
data obtained were compared to those obtained with a monomeric analogue, i.e. CH3CON(Py)2RhCl(COD) (C1, Py = 2-pyridyl).
Using the polymer-supported catalyst under micellar conditions, a significant increase in selectivity, i.e. an increase in the n:iso
ratio was accomplished, which could be further enhanced by the addition of excess ligand, e.g., triphenylphosphite. Special features
of the micellar catalytic set up are discussed.
Page 1 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
Introduction
Catalysts bound to amphiphilic block copolymers find
Synthesis of homo- and block copolymers via
increasing use in micellar catalysis since they combine the ROMP [12,13]
advantages of both homogeneous and heterogeneous catalysis ROMP has already been used for the synthesis of micelle-
in one system. Thus, with catalysts permanently linked to the forming block copolymers [14], however, the one used in this
block copolymer, metal leaching is substantially reduced and study, i.e. poly(M1-b-M2), required special attention. Though
allows for the separation/reuse of the catalyst [1-7]. In cases M1 contains a chelating ligand and can be polymerized by both
where reactions are run in polar media, the catalyst is best Schrock and Grubbs-type initiators [15-18]. M2 is particularly
located inside the hydrophobic micellar core, where, upon problematic since it contains a quaternary ammonium moiety
micelle formation of the functionalized block copolymer, the and has the ability to alkylate the phosphane or pyridine ligands
monomer will also accumulate. This leads to high educt concen- of 1st-, 2nd-, and 3rd-generation Grubbs-type initiators. We
trations at the polymer-bound catalyst, often resulting in high therefore chose one of the most active Schrock-type initiator
reaction rates in water [8]. We recently reported on the synthe- [19-21] for polymerization, i.e. Mo(N-2,6-Me2 -
sis of RhI and IrI complexes of N,N-dipyrid-2-ylacetamide and C6H3)[CHC(CH3)2Ph][OCMe(CF3)2]2 ([Mo]) [22].
their use in hydroformylation reactions [9]. Here, we report on
the immobilization of a Rh-N,N-dipyrid-2-ylacetamide-based Both the homopolymerization of M1 and M2 by the action of
catalyst on a soluble, amphiphilic, ring-opening metathesis [Mo] proceeded smoothly at room temperature. Conversion of
polymerization- (ROMP) derived block copolymer and its use monomer M1 reached 100% after 10 min (Figure S1,
in hydroformylation [10] under micellar conditions [3,5,11]. Supporting Information File 1). The corresponding block
This medium activity and selectivity dipyrid-2-ylamide-based copolymer poly(M1-b-M2) (Mn = 44100 g mol−1, PDI = 1.38,
Rh(I)-catalyst was chosen in order to identify the potential Scheme 2) was prepared in 76% isolated yield by starting the
advantages of a micellar setup.
polymerization with M1 and adding M2 after 20 min. The
GPC-traces of the first and second block are shown in Figure S2
(Supporting Information File 1) and indicate that the diblock
copolymer formed quantitatively. From GPC analysis, degrees
Results and Discussion
Synthesis of monomers
The synthesis of norborn-5-ene-(N,N-dipyrid-2-yl)carbamide of polymerization of 63 and 61 were found for the poly(M1)
(M1) was accomplished via reaction of norborn-5-ene-2- and the poly(M2) block, respectively.
ylcarboxylic acid chloride with dipyrid-2-ylamine in the pres-
Critical micelle forming concentrations, metal
ence of triethylamine as described elsewhere [9]. exo,exo-[2-(3-
Ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-ene-2- loading of poly(M1-co-M2)
carbonyloxy)ethyl]trimethylammonium iodide (M2) was The cmc of poly(M1-co-M2) was determined by fluorescence
prepared in a four-step procedure (Scheme 1). It entailed the spectroscopy [23]. For measurements in water, 6-p-toluidene-2-
reaction of 7-oxanorborn-5-ene-2,3-dicarboxylic anhydride with naphthylsulfonic acid (10−6 mol/L) was used as the fluores-
2-(N,N-dimethylamino)ethan-1-ol, conversion of the free cence probe. A cmcwater for poly(M1-b-M2) of 2.8 ×
carboxylic acid 1 into the corresponding acid chloride with 10−6 mol L−1 was determined (Figure S3, Supporting Informa-
SOCl2 and reaction of the acid chloride with dry ethanol to tion File 1). Next, poly(M1-b-M2) was loaded with Rh(I) via
form the diester 2. Finally, compound 2 was converted into M2 reaction of poly(M1-b-M2) with [RhCl(COD)]2 (COD =
via quaternization of the tertiary amine with methyl iodide.
cycloocta-1,5-diene) to yield poly(M1-b-M2)-Rh (Scheme 2).
Scheme 1: Synthesis of M2.
Page 2 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
Scheme 2: Synthesis of poly(M1-b-M2) and of the micellar catalyst poly(M1-b-M2)-Rh.
A metal loading of 18 mg Rh/g polymer was achieved, which As already described [9], the dipyridylamide-based Rh-catalyst
corresponds to 12% of the theoretical loading (assuming the C1 is a very fast isomerization catalyst. Consequently, consider-
formation of a mono-dipyridyl-Rh(I) complex as observed for able amounts of iso-octanes and a low n:iso ratio of 0.9 was
M1) [9]. Consequently, almost 90% of the dipyrid-2-ylamide reported for this catalyst (Table 1, entry 3).
ligands were not involved in complex formation, which is of
importance for the catalytic behavior of the supported catalyst
Table 1: Results for the hydroformylation of 1-octenea.
and for metal leaching. Poly(M1-b-M2)-Rh was again subject
No. Catalyst
Solvent
TONc TOF0 n:iso
to cmc measurements. A value of 2.2 × 10−6 mol L−1 was
found, indicating that the loading with Rh(I) hardly changes the
cmc value (Figure S4, Supporting Information File 1).
1
2
3
4
poly(M1-b-M2)-Rh water
poly(M1-b-M2)-Rhb water
3800 1200 1.5
4400 1200 2.3
4500 2700 0.9
4700 1600 1.6
C1
toluene
toluene
Hydroformylation under micellar conditions
Generally, micellar catalysis [3,5,24-28] and in particular
micellar set-ups, where catalysts covalently bound to
amphiphilic polymers are used [2,4,29-33], have been reported
to present suitable catalysts for numerous catalytic reactions.
The hydroformylation under micellar conditions using catalysts
C1b
acatalyst:substrate ratio = 1:5000, t = 4 h, T = 70 °C.
btriphenylphosphite:substrate = 10:5000.
cbased on the aldehydes formed.
bound to amphiphilic block copolymers was first reported by When poly(M1-co-M2)-Rh was used in water, a turn-over
Nuyken et al. [34]. Using a poly(2-oxazoline)-based number (TON) of 4700 and an initial turn-over frequency
amphiphilic copolymer and a RhBr(1,3-dialkylimidazol-2- (TOF0) of 1200 h−1 was observed. The n:iso ratio, however,
ylidene-based catalyst, selectivities (n:iso) of ~3 at 40% conver- was higher than the one obtained with C1 in toluene, i.e. 1.5 vs.
sion and an activity (TOF0) of 1630 h−1 in the hydroformyla- 0.9 for C1 (Table 1, entry 1, Figure S5, Supporting Information
tion of 1-octene was observed [35]. Here, we used poly(M1-b- File 1). At 40% conversion, an n:iso ratio of 1.6 (Figure S6,
M2)-Rh for the hydroformylation of 1-octene in water. For Supporting Information File 1) was found. A representative
purposes of comparison, the results obtained were compared to product distribution obtained with poly(M1-co-M2)-Rh is
those previously obtained with the homogeneous analogue shown in Figure 1. This enhanced selectivity is attributed to the
CH3CON(Py)2RhCl(COD) (C1) [9].
presence of a comparably large percentage (88%) of free
Page 3 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
dipyrid-2-ylamide ligands as well as to the high concentration triphenylphosphite) accumulate. Finally and importantly, the
of educts within the micelle. Both apparently suppress β-elimin- leaching of Rh from poly(M1-co-M2)-Rh into the products was
ation in the alkyl-metal species. Consequently, a further add- very low, resulting in metal contaminations of around 9 ppm.
ition of free ligand (e.g., triphenylphosphite), which is known to Again, the large excess of free dipyrid-2-ylamine ligand is
favor the formation of n-aldehydes in homogenous catalysis thought to be responsible for this finding. Moreover, the
[10,36], the n:iso value could be further increased to 2.3 polymer-bound catalyst can be recycled by extracting the
(Table 1, entry 2, Figure 2) and to 2.5 at 40% conversion, products with diethyl ether and reused with only a minor change
respectively (Figure S6, Supporting Information File 1). As a in activity. Thus, the TONs obtained were 4300 and 3900 for
matter of fact, neither ethylheptanal or propylhexanal nor the the first and second run.
parent 3- and 4-octenes was observed in this experiment.
Conclusion
By contrast, the n:iso value increased only to 1.6 with C1 in An amphiphilic block copolymer bearing a chelating N,N-
toluene upon addition of excess ligand (Figure S7, Supporting dipyrid-2-ylamide-based ligand was prepared via ROMP using
Information File 1), clearly demonstrating the effect of the a Mo-based Schrock initiator. Loading with Rh(I) yielded a
micelle, where both the reactants and the additional ligand (i.e. polymer-bound catalyst that was used for the hydroformylation
Figure 1: Conversion (%) of 1-octene, product formation, product distribution, as well as time dependant n:iso ratio in the hydroformylation of
1-octene in water in the presence of poly(M1-b-M2)-Rh.
Figure 2: Conversion of 1-octene, product formation and product distribution in the hydroformylation in water in the presence of poly(M1-b-M2)-Rh
and triphenylphosphite.
Page 4 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
of 1-octene. From the hydroformylation data obtained with the 1,2,3,6-tetrahydrophtalic anhydride (10.0 g, 60.0 mmol),
polymer-bound catalyst as well as with the model catalyst, it 2-dimethylaminoethanol (6.3 mL, 62.0 mmol, 1.03 equiv) and
becomes clear that the use of a micellar catalyst favors the p-toluenesulfonic acid (590 mg, 3.1 mmol, 5 mol%) were
formation of the n-aldehyde by suppressing the isomerization dissolved in 120 mL of THF and stirred at room temperature for
propensity of a catalyst. Apparently, the higher concentration of 8 h. The white precipitate was filtered, washed with diethyl
the starting alkene inside the micelle effectively prevents ether and dried to afford a white solid; yield: 13.8 g (90.0%). 1H
β-elimination, an effect that can be further enhanced by adding NMR (CDCl3): δ 2.70 (s, 6H), 2.78–2.81 (m, 2H), 3.01 (ddd,
free ligand that again accumulates inside the micelle. Further 1H, 2J = 13.7 Hz, J = 6.8 Hz, J = 2.8 Hz), 3.12 (ddd, 1H,
advantages in favor of a micellar setup are the low metal 2J = 13.7 Hz, J = 7.3 Hz, J = 2.8 Hz), 4.37 (ddd, 1H, 2J = 13.3
contamination of the products as well as the possibility of reuse. Hz, J = 7.3 Hz, J = 2.8 Hz), 4.51 (ddd, 1H, 2J = 13.3 Hz, J = 6.8
Hz, J = 2.8 Hz), 5.24 (s br, 2H), 6.37 (dd, 1H, J = 5.7 Hz, J =
Experimental
All manipulations were performed under a N2 atmosphere in a
1.6 Hz), 6.47 (dd, 1H, J = 5.7 Hz, J = 1.6 Hz).
glove box (LabMaster 130, MBraun, Garching, Germany) or by exo,exo-7-Oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid
standard Schlenk techniques unless stated otherwise. Purchased 2-(2-dimethylaminoethyl) ester 3-ethyl ester (2): 1 (1.0 g,
starting materials were used without any further purification. 3.9 mmol) was dissolved in 20 mL of EtOH (c = 0.2 M). SOCl2
Pentane, diethyl ether, toluene, CH2Cl2 and tetrahydrofuran (0.4 mL, 5.9 mmol, 1.5 equiv) was added dropwise at room
(THF) were dried using a solvent purification system (SPS, temperature and the reaction mixture was stirred at room tem-
MBraun). Benzene, n-hexane and dimethoxyethane (DME) perature for 8 h. The solvent was removed in vacuo, the green
were dried and distilled from sodium/benzophenone ketyl under residue dissolved in 25 mL of CH2Cl2 and washed with 10 mL
argon. NMR spectra were recorded at room temperature on a of sat. NaHCO3 solution. The aqueous phase was extracted with
Bruker AM 400 (400 MHz for proton and 100.6 MHz for CH2Cl2 (3 × 10 mL) and the combined organic layers were
carbon) and on a Bruker Avence 600 II+ (600.25 MHz for dried over MgSO4. Finally, the solvent was removed under
proton and 150.93 MHz for carbon) spectrometer, respectively, reduced pressure to afford a yellow oil; yield: 695 mg (60%).
unless specified otherwise. Proton and carbon spectra were 1H NMR (CDCl3): δ 1.29 (t, 3H, J = 7.2 Hz), 2.30 (s, 6H), 2.59
referenced to the internal solvent resonance and are reported in (t, 2H, J = 5.8 Hz), 2.81 (d, 1H, J = 9.0 Hz), 2.88 (d, 1H, J = 9.0
ppm. Molecular weights and polydispersity indices (PDIs) of Hz), 4.16–4.21 (m, 3H), 4.23–4.28 (m, 1H), 5.28 (s, 1H), 5.29
the polymers were determined by GPC at 40 °C on Waters (s, 1H), 6.47 (s, 2H).
columns (Styragel HR 4 DMF, 4.6 × 300 mm) in DMF vs.
poly(styrene) using a Waters 717 plus autosampler and a exo,exo-[2-(3-Ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-
Waters 2414 refractive index detector. For calibration, ene-2-carbonyloxy)ethyl]trimethylammonium iodide (M2):
poly(styrene) samples (PDI < 1.02) with molecular weights 2 (659 mg, 2.3 mmol) was dissolved in 2 mL of CH3I at 0 °C.
within the range 162 < Mn <5,500,000 g/mol were used. The The reaction mixture was stirred for 30 min at 0 °C and for 8 h
flow rate was 1.0 mL/min. Fluorescence testing was performed at room temperature. The resulting yellow precipitate was isol-
using a Perkin-Elmer luminescence spectrometer LS50B. IR ated by filtration, dried and recrystallized from boiling ethanol.
spectra were recorded on a Bruker Vector 22 using ATR tech- The crude product was dissolved in CH2Cl2 and precipitated
nology. Elemental analysis was carried out on Elementar Varia with hexane to afford a white solid; yield: 875 mg (88%). 1H
El (Analytik Jena). GC-MS investigations were carried out on a NMR (CDCl3): δ 1.30 (t, 3H, J = 7.2 Hz), 2.86 (d, 1H, 2J = 9.0
Shimadzu GCMS-QP5050 with an AOC-20i Autosampler using Hz), 2.94 (d, 1H, 2J = 9.0 Hz), 3.54 (s, 9H), 4.16 (q, 2H, J = 7.2
a SPB fused silica (Rxi-5MS) column (30 m × 0.25 mm × Hz), 4.10–4.23 (m, 2H), 4.56 (dd, 1H, 2J = 14.0 Hz, J = 5.1
0.25 μm film thickness, 60.6 kPa, temperature program: 70 °C – Hz), 4.74 (dd, 1H, 2J = 14.0 Hz, J = 6.9 Hz), 5.15 (s br, 1H),
300 °C, 25 min). The Schrock initiator Mo(N-2,6-Me2- 5.43 (s br, 1H), 6.48 (dd, 1H, J = 5.8 Hz, J = 1.4 Hz), 6.50 (dd,
C6H3)[CHC(CH3)2Ph][OCMe(CF3)2]2 [Mo] [22], N,N- 1H, J = 5.8 Hz, J = 1.6 Hz). 13C NMR (CDCl3, 100 MHz): δ
dipyridyl-endo-norborn-5-ene-2-carbamide (M1) [9,37] and 14.24 (CH3), 46.77 (CH), 47.91 (CH), 54.88 (CH3), 58.65
N-acetyl-N,N-dipyrid-2-yl (cyclooctadiene) rhodium chloride (CH2), 61.69 (CH2), 64.75 (CH2), 80.10 (CH), 80.87 (CH),
(C1) [9] were synthesized according to the literature.
136.52 (CH), 136.76 (CH), 171.19 (Cq), 172.00 (Cq). IR (ATR)
ν (cm−1) = 3433 (w), 3002 (w), 2977 (w), 1732 (ss), 1190 (ss),
exo,exo-[2-(3-Ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-en- 1157 (ss) 913 (s), 887 (s). Elemental analysis: calcd. for
2-carbonyloxy)ethyl]trimethylammonium iodide (M2) C15H24INO5: C, 42.36; H, 5.69; N, 3.29; found: C, 42.25; H,
exo,exo-7-Oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid 5.71; N, 3.29.
mono(2-dimethylaminoethyl) ester (1): exo-3,6-Epoxy-
Page 5 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
Homopolymerization of M1: M1 (100 mg, 0.339 mmol) was (broad s, CH2), 4.70 (broad s, CH2), 4.21 (broad d, CH2), 3.51
dissolved in 5 mL of CH2Cl2 and treated with a solution of (broad s, NBE + NCH3), 1.87 (broad, NHE), 1.27 (CH3). 13C
[Mo] (2.4 mg, 0.0034 mmol) in 1 mL of CH2Cl2. The yellow NMR (CDCl3): δ 175.6 (C=O), 171.3 and 170.4 (C=O), 154.8,
reaction mixture was stirred for 2 h at room temperature. A 148.9, 137.8, 134.6 and 130.2 (all Py), 122.8 and 122.2
solution of ferrocene carboxaldehyde (10-fold excess based on (-CH=CH-), 77.0 (NBE), 64.6, 61.6, 59.3 (CH2), 52.8 (NCH3),
initiator) in CH2Cl2 was added and the mixture was stirred for 22.3, 14.1 (CH3). FT-IR (ATR mode): ν (cm−1) = 3404 (w),
1 h at room temperature. The polymer was precipitated by add- 2937 (w), 1727 (s), 1679 (m), 1586 (m), 1467 (m), 1432 (w),
ition of pentane, filtered off, thoroughly washed with pentane 1375 (m), 1238 (w), 1184 (s), 1097 (w), 1018 (m), 954 (m), 749
and dried; yield: 85 mg (85%). Poly(M1): Mn(calc) = 29400 g (m).
mol−1, Mn(found) = 37900 g mol−1; PDI = 1.21. 1H NMR
(CDCl3): δ 8.39 (broad d, 2H Py), 7.72 (broad d, 2H Py), 7.34 Synthesis of poly(M1-b-M2)-Rh: [Rh(COD)2Cl]2 (8 mg) was
(broad d, 2H Py), 7.14 (broad d, 2H Py), 5.72–5.43 (broad t, 2H dissolved in CH2Cl2. This solution was added dropwise to a
-CH=CH-), 3.12 (broad s, 1H NBE), 2.89–2.23 (broad d, 2H suspension of poly(M1-b-M2) (100 mg) in 5 mL of CH2Cl2.
NBE), 2.20–1.20 (broad d, 4H NBE). 13C NMR (CDCl3): δ The mixture was stirred for 10 h at room temperature; then the
175.0 (C=O), 154.8, 148.9, 137.8, 134.6 and 130.2 (all Py), polymer was filtered off, thoroughly washed with pentane and
122.6 and 121.9 (-CH=CH-), 53.3, 47.6, 41.9 and 37.3 (all dried; yield: 100 mg (92%). The Rh-content was determined by
NBE). FT-IR (ATR mode): ν (cm−1) = 2995 (w), 1672 (s), ICP-OES: 18 mg Rh/g copolymer (12% of the theoretical
1577 (s), 1426 (m), 1239 (w), 1048 (m), 739 (m).
loading).
Homopolymerization of M2: M2 (100 mg, 0.235 mmol) was cmc determination of poly(M1-b-M2) and poly(M1-b-M2)-
dissolved in 5 mL of CH2Cl2 and treated with a solution of Rh: The cmc in water were determined by fluorescence spec-
[Mo] (3.0 mg, 0.0042 mmol) in 1 mL of CH2Cl2. The resulting troscopy [23] using 6-p-toluidene-2-naphthylsufonic acid
white cloudy reaction mixture was stirred for 2 h at room tem- (10−6 M) as the fluorescence probe. Polymer solutions were
perature. A solution of ferrocene carboxaldehyde (10-fold prepared in a concentration range from 1 × 10−4–1 × 10–13 mol
excess based on initiator) in CH2Cl2 was added and the mixture L–1. cmc of poly(M1-b-M2) = 2.8 × 10−6 mol L−1; cmc of
was then stirred for 1 h at room temperature. The polymer was poly(M1-b-M2)-Rh = 2.2 × 10−6 mol L−1.
filtered off, thoroughly washed with pentane and dried; yield:
90 mg (90%). Poly(M2): Mn(calc) = 23600 g mol−1, Mn(found) = Quantification of Rh: The amount of Rh bound to the block
24500 g mol−1, PDI = 1.36. 1H NMR (CDCl3): δ 5.83 (broad s, copolymers or leached into the products was determined by
2H -CH=CH-), 5.17 (broad s, 2H CH2), 4.70 (broad s, 2H CH2), dissolving a 20.0 mg amount of the polymer or the product mix-
4.21 (broad d, 4H CH2), 3.51 (broad s, 13 H NBE + NCH3), ture in aqua regia (25 mL). Rh was quantified by ICP-OES at
1.26 (broad s, 3H CH3). 13C NMR (CDCl3): δ 171.3 and 170.4 λ = 343.489 nm, measuring the background at λ1 = 343.410 and
(C=O), 132.7(-CH=CH-), 77.2 (NBE), 64.6, 61.8, 59.4 (CH2), λ2 = 343.600 nm, respectively. A 1000 ppm Rh standard (1N
55.1, 53.8 and 52.9 (NCH3), 14.1 (CH3). FT-IR (ATR mode): ν HNO3, Merck, Germany) was used to prepare standards of 0,
(cm−1) = 3428 (w), 2969 (w), 1726 (s), 1427 (m), 1181 (w), 0.100, 1.00 and 10.00 ppm.
1018 (m), 953 (m).
General procedure for hydroformylation: The reaction was
Synthesis of poly(M1-b-M2): A solution of [Mo] (2.4 mg, carried out in a 300 mL Parr high-pressure reactor. The reactor
0.0034 mmol) in 1 mL of CH2Cl2 was added to one of M1 was evacuated, flushed with argon and filled with the catalyst,
(30.0 mg, 0.102 mmol) in 1 mL of CH2Cl2. The reaction mix- water or toluene (30 mL), and 1-octene (1.0 g, 0.0090 mol),
ture was stirred for 20 min and a small amount was withdrawn leading to a substrate to catalyst ratio of 5000:1. tert-Butylben-
for GPC measurements. M2 (100 mg, 0.235 mmol) was zene (1.00 mL) was added as internal standard. To purge the
dissolved in 2 mL of CH2Cl2 and this solution was added to the reactants, the mixture was pressurized with a 1:1 mixture of CO
reaction mixture. The resulting white cloudy reaction mixture and H2 up to a pressure of 30 bar and then the pressure was
was stirred for another 90 min. The polymerization was termin- released. Finally, the pressure was adjusted to 50 bar with the
ated with ferrocene carboxaldehyde (10-fold excess based on aid of a back pressure regulator. The autoclave was heated to
initiator) and the reaction was stirred for a further hour. The 70 °C and kept at this temperature. Samples were taken every
polymer was filtered off, thoroughly washed with pentane and 30 min. The isomeric 1-octenes and aldehydes were identified
dried; yield: 100 mg (76%). Mn = 44100 g mol−1, and quantified by their MS spectra as well as by their retention
Mw = 61100 g mol−1, PDI = 1.38. 1H NMR (CDCl3): δ 8.40, times using commercially available compounds as reference
7.92, 7.43, 7.33 (broad s, Py), 5.79 (broad s, -CH=CH-), 5.17 material.
Page 6 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
5. Oehme, G. Micellar Systems. In Multiphase Homogeneous Catalysis,
1st ed.; Cornils, B.; Herrmann, W. A.; Horvath, I. T.; Leitner, W.;
Mecking, S.; Olivier-Bourbigou, H.; Vogt, D., Eds.; Wiley-VCH:
Weinheim, Germany, 2005; Vol. 1, pp 132–136.
6. Pawar, G.; Bantu, B.; Weckesser, J.; Blechert, S.; Wurst, K.;
Buchmeiser, M. R. Dalton Trans. 2009, 9043–9051.
doi:10.1039/b909180g
Recyclability studies with poly(M1-b-M2)-Rh: Hydro-
formylations were carried out as described above. For recycling,
the product was extracted with diethyl ether (4 × 10 mL). Fresh
1-octene (1.0 g, 0.0090 mol), and tert-butylbenzene (1.0 mL)
were added to the aqueous, catalyst-containing phase and the
reaction was run under the same conditions as before. The
TONs in two consecutive cycles as determined by GC-MS were
4300 and 3900, respectively.
7. Weberskirch, R.; Preuschen, J.; Spiess, H. W.; Nuyken, O.
Macromol. Chem. Phys. 2000, 201, 995–1007.
doi:10.1002/1521-3935(20000601)201:10<995::AID-MACP995>3.0.CO
;2-T
8. Krause, J. O.; Zarka, M. T.; Anders, U.; Weberskirch, R.; Nuyken, O.;
Buchmeiser, M. R. Angew. Chem. 2003, 115, 6147–6151.
doi:10.1002/ange.200352637
Supporting Information
Supporting Information contains polymerization kinetics of
M1 by the action of Mo(N-2,6-Me2
9. Bantu, B.; Wurst, K.; Buchmeiser, M. R. J. Organomet. Chem. 2007,
692, 5272–5278. doi:10.1016/j.jorganchem.2007.08.009
10.Ungváry, F. Coord. Chem. Rev. 2007, 251, 2087–2102.
doi:10.1016/j.ccr.2007.02.018
C6H3)(CHCMe2Ph)(OCMe(CF3)2)2, GPC-traces (DMF) of
poly(M1) and poly(M1-b-M2); cmc measurements for
poly(M1-b-M2) and poly(M1-b-M2)-Rh in water;
conversion of 1-octene, product formation, product
distribution in the hydroformylation of 1-octene in toluene
in the presence of C1, C1 and triphenylphosphite; n:iso
selectivities for catalysts poly(M1-b-M2)-Rh) and
poly(M1-b-M2)-Rh with triphenylphosphite as a function
of conversion.
11.Holmberg, K. Eur. J. Org. Chem. 2007, 731–742.
doi:10.1002/ejoc.20060074
12.Buchmeiser, M. R. Ring-Opening Metathesis Polymerization. In
Handbook of Ring-Opening Polymerization, 1st ed.; Dubois, P.;
Coulembier, O.; Raquez, J.-M., Eds.; Wiley-VCH: Weinheim, Germany,
2009; pp 197–225. doi:10.1002/9783527628407.ch8
13.Buchmeiser, M. R. Chem. Rev. 2000, 100, 1565–1604.
doi:10.1021/cr990248a
14.Stubenrauch, K.; Moitzi, C.; Fritz, G.; Glatter, O.; Trimmel, G.;
Stelzer, F. Macromolecules 2006, 39, 5865–5874.
doi:10.1021/ma060451p
Supporting Information File 1
Graphical representations of measurements.
[http://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-6-28-S1.pdf]
15.Buchmeiser, M. R.; Wurst, K. J. Am. Chem. Soc. 1999, 121,
11101–11107. doi:10.1021/ja991501r
16.Buchmeiser, M. R.; Lubbad, S.; Mayr, M.; Wurst, K. Inorg. Chim. Acta
2003, 345, 145–153. doi:10.1016/S0020-1693(02)01291-4
17.Trnka, T. M.; Grubbs, R. H. Acc. Chem. Res. 2001, 34, 18–29.
doi:10.1021/ar000114
Acknowledgements
18.Grubbs, R. H. Angew. Chem. 2006, 118, 3845–3850.
doi:10.1002/ange.200600680
Our work was supported by Clariant Germany, the Cluster of
Excellence “Unifying Concepts in Catalysis” coordinated by the
Technische Universität Berlin and the Federal Government of
Germany and the Freistaat Sachsen. We are grateful to Dr.
Wolfgang Geyer (UFZ, Leipzig) for his kind help with the
fluorescence measurements as well as to A. Prager and Dr. U.
Decker (IMO, Leipzig) for ICP-OES and NMR measurements.
19.Schrock, R. R. Polyhedron 1995, 14, 3177–3195.
doi:10.1016/0277-5387(95)85005
20.Schrock, R. R. The Discovery and Development of High-Oxidation
State Mo and W Imido Alkylidene Complexes for Alkene Metathesis. In
Handbook of Metathesis, 1st ed.; Grubbs, R. H., Ed.; Wiley-VCH:
Weinheim, Germany, 2003; Vol. 1, pp 8–32.
doi:10.1002/9783527619481.ch3
21.Schrock, R. R. Chem. Commun. 2005, 2773–2777.
doi:10.1039/b504541j
References
1. Kotre, T.; Zarka, M. T.; Krause, J. O.; Buchmeiser, M. R.;
Weberskirch, R.; Nuyken, O. Macromol. Symp. 2004, 217, 203–214.
doi:10.1002/masy.200451316
22.Oskam, J. H.; Fox, H. H.; Yap, K. B.; McConville, D. H.; O’Dell, R.;
Lichtenstein, B. J.; Schrock, R. R. J. Organomet. Chem. 1993, 459,
185–198. doi:10.1016/0022-328X(93)86071-O
23.Ananthapadmanabhan, K. P.; Goddard, E. D.; Turro, N. J.; Kuo, P. L.
Langmuir 1985, 1, 352–355. doi:10.1021/la00063a015
24.Dwars, T.; Haberland, J.; Grassert, I.; Oehme, G.; Kragl, U.
J. Mol. Catal. A: Chem. 2001, 168, 81–86.
2. Nuyken, O.; Persigehl, P.; Weberskirch, R. Macromol. Symp. 2002,
177, 163–173.
doi:10.1002/1521-3900(200201)177:1<163::AID-MASY163>3.0.CO;2-
W
doi:10.1016/S1381-1169(00)00542-2
3. Nuyken, O.; Weberskirch, R.; Kotre, T.; Schoenfelder, D.; Wörndle, A.
Polymers for micellar catalysis. In Polymeric Materials in Organic
Synthesis and Catalysis; Buchmeiser, M. R., Ed.; Wiley-VCH:
Weinheim, Germany, 2003; pp 277–304. doi:10.1002/3527601856.ch6
4. Nuyken, O.; Weberskirch, R.; Bortenschlager, M.; Schönfelder, D.
Macromol. Symp. 2004, 215, 215–230. doi:10.1002/masy.200451118
25.Morawetz, H. Adv. Catal. 1969, 20, 341–371.
doi:10.1016/S0360-0564(08)60276-X
26.Lipshutz, B. H.; Aguinaldo, G. T.; Ghorai, S.; Voigtritter, K. Org. Lett.
2008, 10, 1325–1328. doi:10.1021/ol800028x
Page 7 of 8
(page number not for citation purposes)

Beilstein Journal of Organic Chemistry 2010, 6, No. 28.
27.Mingotaud, A.-F.; Mingotaud, C.; Moussa, W.
J. Polym. Sci., Part A: Polym. Chem. 2008, 46, 2833–2844.
doi:10.1002/pola.22617
28.Oheme, G.; Grassert, I.; Paetzold, E.; Meisel, R.; Drexler, K.;
Fuhrmann, H. Coord. Chem. Rev. 1999, 185-186, 585–600.
doi:10.1016/S0010-8545(99)00012-0
29.Kotre, T.; Nuyken, O.; Weberskirch, R. Macromol. Rapid Commun.
2002, 23, 871–876.
doi:10.1002/1521-3927(20021001)23:15<871::AID-MARC871>3.0.CO;
2-G
30.Zarka, T. M.; Nuyken, O.; Weberskirch, R. Chem.–Eur. J. 2003, 9,
3228–3234. doi:10.1002/chem.200304729
31.Kotre, T.; Nuyken, O.; Weberskirch, R. Macromol. Chem. Phys. 2004,
205, 1187–1195. doi:10.1002/macp.200300241
32.Schönfelder, D.; Nuyken, O.; Weberskirch, R. J. Organomet. Chem.
2005, 690, 4648–4655. doi:10.1016/j.jorganchem.2005.07.053
33.Schönfelder, D.; Fischer, K.; Schmidt, M.; Nuyken, O.; Weberskirch, R.
Macromolecules 2005, 38, 254–262. doi:10.1021/ma048142r
34.Zarka, M. T.; Bortenschlager, M.; Wurst, K.; Nuyken, O.;
Weberskirch, R. Organometallics 2004, 23, 4817–4820.
doi:10.1021/om049495h
35.Bortenschlager, M.; Wittmann, A.; Schoellhorn, N.; Weberskirch, R.;
Nuyken, O. Polym. Prepr. 2005, 46, 666–667.
36.Weissermel, K.; Arpe, H. J. Industrial Organic Chemistry; VCH: New
York, 1993.
37.Sinner, F.; Buchmeiser, M. R.; Tessadri, R.; Mupa, M.; Wurst, K.;
Bonn, G. K. J. Am. Chem. Soc. 1998, 120, 2790–2797.
doi:10.1021/ja973495+
License and Terms
This is an Open Access article under the terms of the
Creative Commons Attribution License
(http://creativecommons.org/licenses/by/2.0), which
permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
The license is subject to the Beilstein Journal of Organic
Chemistry terms and conditions:
(http://www.beilstein-journals.org/bjoc)
The definitive version of this article is the electronic one
which can be found at:
doi:10.3762/bjoc.6.28
Page 8 of 8
(page number not for citation purposes)