Bio-supported palladium nanoparticles as a catalyst for Suzuki-Miyaura and Mizoroki-Heck reactions

Article abstract of DOI:10.1039/b918351p

The biological synthesis of metal nanoparticles from ions has recently emerged as a novel technique for an environmentally benign recovery of heavy metals. Bacteria are known to recover palladium(0) in the form of nanoparticles that are catalytically active. However, the extent of the reactions that can be catalysed by bio-recovered palladium has not been investigated. This study demonstrates that the Suzuki-Miyaura and Mizoroki-Heck reactions can be catalysed by bio-generated palladium nanoparticles formed on the surface of Gram-negative bacteria. The results suggest that the range of applications of this catalyst can be extended to the realm of carbon-carbon bond formation in synthetic organic chemistry.

Full text of DOI:10.1039/b918351p

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/greenchem | Green Chemistry
Bio-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura
and Mizoroki–Heck reactions†‡
Lina Sveidal Søbjerg,a Delphine Gauthier,a Anders Thyboe Lindhardt,b Michael Bunge,a Kai Finster,c
Rikke Louise Meyer*a,c and Troels Skrydstrup*a,b
Received 30th June 2009, Accepted 4th September 2009
First published as an Advance Article on the web 14th October 2009
DOI: 10.1039/b918351p
The biological synthesis of metal nanoparticles from ions has recently emerged as a novel
technique for an environmentally benign recovery of heavy metals. Bacteria are known to recover
palladium(0) in the form of nanoparticles that are catalytically active. However, the extent of the
reactions that can be catalysed by bio-recovered palladium has not been investigated. This study
demonstrates that the Suzuki–Miyaura and Mizoroki–Heck reactions can be catalysed by
bio-generated palladium nanoparticles formed on the surface of Gram-negative bacteria. The
results suggest that the range of applications of this catalyst can be extended to the realm of
carbon–carbon bond formation in synthetic organic chemistry.
nanocrystals of Pd(0). This simple protocol involves biosorption
Introduction
of Pd(II) cations on the surface of bacteria and a subsequent re-
There is no longer doubt that the development of sustainable
duction to Pd(0) crystals using an electron donor. The nanopar-
chemistry will motivate the emergence of efficient processes
ticles formed are supported either on the bacterial outer mem-
to solve current environmental issues for the generations to
brane or in the periplasmic space and remain attached to the
come. Limitation of natural resources, reduction of wastes,
cells (“bio-Pd(0)”).14,15 Bio-recovered Pd(0) by Gram-negative16
maximising renewability, and development of environmentally
and Gram-positive17 bacteria have been reported to catalyse effi-
benign reagents are the next challenges for the chemical sciences.
ciently hydrogenation reactions,18 chromium reduction,8,11 poly-
An important part of modern day chemistry is based on the use
chlorinated biphenyls (PCB) dechlorination,14,19 reduction of
of precious platinum group metal (PGM) catalysts. Palladium
perchlorate19 and formation of hydrogen from hypophosphite.21
(Pd), a popular PGM used mainly in catalytic converters, is an
Hence, this process for the generation of metal nanoparticles
expensive metal with a high demand. The price of Pd metal varies
represents a significant step in the direction of developing
concurrently with fluctuating supplies caused by the limited
environmentally friendly catalysts.
geographical distribution of Pd mines.1 Recovery of waste Pd is
In this study, we have explored the possibility of applying bio-
therefore of prime importance. Current techniques include costly
Pd for construction of carbon–carbon bonds in synthetic organic
and non-ecological processes, such as pyrometallurgy, solvent
chemistry. Furthermore, we have investigated whether the parti-
extraction, chemical treatment and electrochemical recovery.2
cle size of bio-Pd affects its catalytic properties. Pd(0) has been
Therefore, alternative environmentally benign processes for the
extensively employed to catalyse various C–C bond forming
recovery of Pd are of high interest.
One such method exploits the capacity of bacteria to re-
reactions such as the Suzuki–Miyaura and the Mizoroki–Heck
reactions, allowing the elaboration of complex and valuable
duce transition metal ions like Pd. Certain strains of bacte-
structures.20 We present here the first examples of these types
ria (e.g. Desulfovibrio desulfuricans,3–11 Escherichia coli4–11 and
of reactions catalysed by bio-generated Pd nanoparticles. Bio-
Pd(0) was formed on cells of two Gram-negative proteobacteria,
Cupriavidus necator and Pseudomonas putida, which promote
Shewanella oneidensis12–14) can reduce soluble Pd(II) from stock
solutions or acid extracts of spent catalysts, forming metallic
morphologically different Bio-Pd(0).
aInterdisciplinary Nanoscience Center (iNANO), Aarhus University, Ny
Results and discussion
Munkegade 120, 8000, Aarhus C, Denmark
bDepartment of Chemistry, Aarhus University, Langelandsgade 140,
Bio-generation of Pd(0)
8000, Aarhus C, Denmark. E-mail: ts@chem.au.dk; Fax: (+45) 8619
9169; Tel: (+45) 8942 3932
The bio-Pd was prepared according to the following proto-
col. After growth and harvesting of the bacteria (C. neca-
tor or P. putida), an aqueous solution of the Pd(II) source
(Na2PdCl4) was added to the cells suspended in anaerobic 3-
(N-morpholino)propanesulfonic acid (MOPS) buffer followed
by the addition of an electron donor (formate). The reduction
occurred within hours, whereafter the suspension turned from
cDepartment of Biological Sciences, Aarhus University, Ny Munkegade
114, Building 1540, 8000, Aarhus C, Denmark. E-mail: rikke.meyer@
biology.au.dk; Fax: (+45) 8942 2722; Tel: (+45) 8942 3305
† This paper is dedicated to Professor Klaus Bock on the occasion of his
65th birthday.
‡ Electronic supplementary information (ESI) available: Experimental
procedures and spectroscopic data (1H NMR, 13C NMR, GCMS) for
all the compounds. See DOI: 10.1039/b918351p
This journal is
The Royal Society of Chemistry 2009
Green Chem., 2009, 11, 2041–2046 | 2041
©

View Article Online
light orange to black. The buffer was then removed from the
bio-Pd by centrifugation, and the recovered bio-Pd pellet was
used directly as the catalyst without further purification.21
The bio-Pd generated in the presence of the two strains
had distinctly different appearances when observed by visual
inspection and by transmission electron microscopy (TEM)
(Fig. 1). P. putida furnished a poorly dispersed bio-Pd, forming
large aggregates, whereas finely dispersed bio-Pd was obtained
in the C. necator suspensions. TEM images revealed that bio-
Pd supported by both organisms consisted of Pd particles in
different sizes ranging from a few nm to hundreds of nm (Fig. 2),
and that the particles were associated with the cell surface
(Fig. 1). A general trend was that Pd particles were larger in the
poorly dispersed sample with P. putida (Fig. 2). Other studies
by Macaskie et al.15 and De Windt et al.14 have shown that
small Pd particles can be located in the periplasmic space of
Gram-negative bacteria. Indeed, in our case, both types of bio-
Pd obtained had particles under 10 nm in size (Fig. 2), which
corresponds to the width of the periplasmic space.
first because of the smaller and better dispersed particles.
Initially, phenylboronic acid and p-iodotoluene were chosen
as the coupling partners. Various temperatures, bases (organic
or inorganic), solvents and mixtures of solvent were screened
in order to establish ideal coupling conditions. The reaction
of p-iodotoluene with 1.1 equivalent of phenylboronic acid in
the presence of Na2CO3 (3 equiv) and tetra-t-butylammonium
bromide TBAB (2 equiv.) in a solvent mixture of EtOH–H2O
(2 : 1) at 50 ◦C provided a 96% yield of the coupling product
(Table 1, entry 2), and these reaction conditions were chosen for
the further experiments. The same reaction carried out in the
absence of the bio-Pd catalyst did not lead to the formation of
the biaryl product.22
With this catalytic system in hand, we then examined this cou-
pling reaction with a variety of aryl iodides and phenylboronic
acid (Table 1).23 High yields were obtained with both activated
(Table 1, entries 3–8) and nonactivated aryl iodides (entries
9 and 10). Despite extensive experimentation, all attempts to
include the aryl bromides as electrophiles failed. In comparison
to commercially available palladium nanopowder (< 25 nm), the
reactivity of bio-Pd was similar in the case of an aryl iodide, but
lower in the case of an aryl bromide (Table 1, entries 9 and 11).
Next, the ability of the bio-Pd to promote the Mizoroki–
Heck reaction was studied in the coupling of n-butylacrylate
with a variety of aryl halides (Table 2). The reaction conditions
described by Reetz et al. in their study on the same reaction
with commercial Pd nanoparticles were applied (Table 2).23,24
As observed in the Suzuki–Miyaura reaction, both activated
and nonactivated aryl iodides underwent successful coupling in
good to excellent yields under bio-Pd catalysis (entries 1–10).
Gratifyingly, the activated aryl bromides also proved reactive
under these conditions though with the addition of TBAB
(entries 11–13). Again, control experiments confirmed that no
reaction occurred without the presence of the added catalyst.
The reactivity of the bio-Pd and the palladium nanopowder was
comparable for the aryl iodides (entries 1 and 5). Changing the
olefin from acrylate to acrylamide did not affect the reactivity
(entries 14 and 15). However, nonactivated aryl bromides or
activated aryl chlorides were not sufficiently reactive under the
conditions used.
Fig. 1 (A) Poorly dispersed bio-Pd(0) obtained from P. putida: visual
inspection (A1) and TEM images (A2, A3). (B) Finely dispersed bio-
Pd(0) generated in the presence C. necator: visual inspection (B1) and
TEM images (B2, B3).
Attention was then turned to the other Gram-negative
bacterium, P. putida, in order to examine the reactivity of
the highly aggregated bio-Pd supported by this organism. The
reactivity of the P. putida bio-Pd in the Mizoroki–Heck reaction
is depicted in Table 3. Comparison with the results obtained
from the same reaction catalysed with the bio-Pd from C.
necator (Table 2, entries 1, 7 and 11) shows that both samples of
bio-Pd catalyse these couplings efficiently with the substrates
tested, and that particle size is not important in this case.
The reactivity of the P. putida bio-Pd was also tested in the
Suzuki–Miyaura cross-coupling between phenylboronic acids
and p-iodoanisole, leading to a 100% yield of the biaryl product.
However, no conversion was observed for p-bromobenzonitrile,
which is equivalent to that noted with the C. necator bio-Pd
(Table 1, entries 9, 11).
Fig. 2 Palladium particle distribution calculated from TEM images.
Catalytic activity of the bio-Pd(0)
The recyclability and the fate of the bio-Pd catalyst was also
tested, using C. necator as the bacterial strain. Recycling of
the catalyst was performed after the coupling of p-iodotoulene
and phenylboronic acid in the Suzuki–Miyaura cross-coupling.
We then set out to test the catalytic activity of the bio-Pd
for promoting the Suzuki–Miyaura cross-coupling reaction.
The bio-Pd formed in C. necator suspensions was examined
2042 | Green Chem., 2009, 11, 2041–2046
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
Table 1 Suzuki–Miyaura coupling of aryl iodides with phenylboronic
acid under C. necator bio-Pd(0) catalysisa
Table 2 Mizoroki–Heck reactions under C. necator bio-Pd(0)
catalysisa
Entry
1
Aryl halide
R
Yieldb (%)
97c,d (93)e
Entry
1
Aryl halide
Yieldb (%)
86
COOn-Bu
2
3
4
5
6
COOn-Bu
COOn-Bu
COOn-Bu
COOn-Bu
COOn-Bu
98c
2
3
4
5
6
7
96d
79
100
100
84
88 (99)e
86
97
85
100
7
8
COOn-Bu
COOn-Bu
96
81
8
97
9
100c (100)e
89
9
COOn-Bu
COOn-Bu
COOn-Bu
COOn-Bu
COOn-Bu
CONH-t-Bu
CONH-t-Bu
86
10
10
11
12
13
14
15
96
97c
88c
53c
81
11
0 (54)e
a Reaction conditions: aryl iodide (0.30 mmol), boronic acid (0.33 mmol),
TBAB (0.60 mmol), Na2CO3 (0.90 mmol), bio-Pd(0) (≤ 2 mol%) from
C. necator in EtOH–H2O (2 : 1, 1.5 mL) at 50 ◦C for 6–16 h. b Isola◦ted
yields after column chromatography. c 4-Iodoanisole was stirred at 80 C.
d 4-Iodotoluene (0.39 mmol) and phenylboronic acid (0.33 mmol) were
used. e < 25 nm palladium powder, CAS-number: 7440-05-3 was used
as the palladium source.
The reaction was performed on a scale twice the size of that
as indicated in Table 1, and the reaction time for each coupling
cycle was 24 h. After each cycle the vial was centrifuged, yielding
the catalyst as a pellet. The pellet was washed twice with ethanol
before the catalyst was reapplied to a coupling reaction. After
the catalyst had been reused 4 times (yield: 91%, 97%, 97%,
95%), no loss of activity was found. The fate of the catalyst was
examined by TEM after the catalyst had been used in the first
coupling and then after the fourth recycling procedure. While the
99
a Reaction conditions: aryl halide (0.20 mmol), olefin (0.40 mmol),
Na2CO3 (0.50 mmol), bio-Pd(0) (≤ 1 mol%) from C. necator in
DMF (2.0 mL) at 80 ◦C for 24 h. b Isolated yields after column
chromatography. c With TBAB (0.40 mmol). d Reaction was run for 12 h.
e < 25 nm palladium nanopowder, CAS-number: 7440-05-3 was used as
the palladium source.
This journal is
The Royal Society of Chemistry 2009
Green Chem., 2009, 11, 2041–2046 | 2043
©

View Article Online
Table 3 The catalytic activity of the bio-Pd from P. putida in the
have shown that the bio-Pd catalysis may represent a practical
and simple means of sustainable organometallic chemistry. This
method represents a green alternative to conventional processes
for the recovery of important transition metals from wastes.
Further studies are now ongoing to investigate the possibility
of applying this approach of recycling and reactivation of Pd to
industrial wastes.
Mizoroki–Heck reactiona
Entry
1
Aryl halide
Yieldb (%)
99
Experimental
Preparation of bacteria
2
3
96
88
The two bacterial strains used in this article were Cupriavidus
necator ATCC 43291 and Pseudomonas putida ATCC 12633.
The strains were grown in 150 mL growth liquid media (5 g L-1
Peptone, 3 g L-1 Meat Extract, pH 7) at 30 ◦C on a shaking
table (120 rpm) until an optical density of OD600=1 was reached
after approximately 16 h. The cultures were then transferred to
50 mL falcon tubes and harvested by centrifugation (10 min,
4416 rpm), washed in anaerobic MOPS-buffer (20 mM, 3 ¥
30 mL) and finally suspended in anaerobic MOPS-buffer to an
OD600=1.
a Reaction conditions: aryl halide (0.20 mmol), olefin (0.40 mmol),
Na2CO3 (0.50 mmol), bio-Pd(0) (≤ 1 mol%) from P. putida in DMF
(2.0 mL) at 80 ◦C for 24 h. b Isolated yields after column chromato-
graphy.
bio-Pd did not alter appearance after the first coupling reaction,
we found a few cells in the bio-Pd after reusing it 4 times. This
was presumably due to cell lysis, although it was difficult to
determine whether the palladium was still attached to the cell
debris. The bacteria are not viable after formation of bio-Pd,
and it would be expected that the cell structure is eventually
disrupted. Due to the lack of cell viability, the bio-Pd waste does
not need to be handled differently from other Pd wastes.
Finally, we examined the possibility of producing catalytically
active bio-Pd from Pd(II) salts from waste materials. The waste
material for this study was obtained from a hydrogenation
reaction with Pd/C as the Pd source. The Pd containing waste
was first submitted to oxidation in aqua regia, whereby all
solid Pd materials were transformed into soluble Pd(II).25 After
neutralisation of the excess acid, the Pd(II) containing solution
was subjected to reduction in the presence of C. necator with
formate as the reductant. The bio-Pd was separated from the so-
lution by centrifugation and used as a catalyst in the Mizoroki–
Heck reaction of p-iodoanisole with n-butylacrylate (Scheme 1).
The coupling product, n-butyl (E)-3-(4-methoxyphenyl)acrylate,
could be furnished in a high 90% isolated yield. Half of the
palladium was recovered using this procedure, and we are
currently working on increasing the efficiency of the recovery
using industrial waste as the palladium source.
Bio-reduction of Pd
The bacterial cell suspension (10 mL, OD600=1) and a degassed
solution of Na2PdCl4 (6.80 mM, 0.5 mL) in MilliQ water were
added to a sealed glass tube and flushed with nitrogen. After
5 min, a degassed solution of formate (1 M, 0.25 mL) in MilliQ
water was added, and the tube was placed on a shaking table
overnight at 30 ◦C giving bio-Pd as black aggregates. The formed
bio-Pd was then separated from the solution by centrifugation
(10 min, 4416 rpm) and removal of the supernatant.
Fixation for TEM
The bacterial cell suspension after bioreduction (100 mL) was
added to a sterile eppendorf tube and a 25% aqueous solution
of glutaric aldehyde (20 mL) was added. The eppendorf tube
was shaken and left for 10 min. The solution was hereafter
centrifuged (2 min, 14000 rpm), washed with MilliQ water (3x
200 mL) and finally diluted in MilliQ water to a total volume of
200 mL.
4-Methylbiphenyl (Table 1, entry 2)26
4-Iodotoluene (85.0 mg, 0.39 mmol), phenylboronic acid
(40.2 mg, 0.33 mmol), bio-Pd from C. necator suspensions
(10 mg, 7 mmol), Na2CO3 (95.4 mg, 0.90 mmol), TBAB
(193.4 mg, 0.60 mmol) were added to a sample vial in a glovebox.
EtOH (1 mL) and H2O (0.5 mL) were added and the sample vial
was fitted with a teflon sealed screwcap and removed from the
glovebox. The reaction mixture was heated to 50 ◦C for 6 h
and then cooled to 20 ◦C. The crude reaction mixture was then
filtered through a filter paper and concentrated in vacuo. The
crude product was purified by flash chromatography on silica gel
using pentane as eluent affording the title compound (53.1 mg,
96% yield) as a colourless solid. 1H NMR (400 MHz, CDCl3) dH
(ppm) 7.62 (d, 2H, J = 7.6 Hz), 7.53 (d, 2H, J = 6.4 Hz), 7.46
(t, 2H, J = 7.6 Hz), 7.36 (t, 1H, J = 7.6 Hz), 7.28 (d, 2H, J =
7.6 Hz), 2.44 (s, 3H). 13C NMR (100 MHz, CDCl3) dC (ppm)
Scheme 1 Mizoroki–Heck reaction with bio-Pd(0) recovered from a
waste solution.
Conclusions
In conclusion, we have demonstrated the ability of bio-Pd to
catalyse two important carbon–carbon bond forming reactions,
namely the Suzuki–Miyaura and Mizoroki–Heck couplings. We
2044 | Green Chem., 2009, 11, 2041–2046
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
154.4, 141.3, 138.5, 137.1, 129.6 (2C), 128.8 (2C), 127.13 (2C),
127.11 (2C), 21.2. GCMS calcd for C13H12 [M]: 168. found: 168.
to a sealed glass tube and flushed with nitrogen. Then, a degassed
solution of the Pd waste (0.11 mM, 3.8 mL) was added to the
resuspension. After 5 min, a degassed solution of formate (1 M,
1 mL) in MilliQ water was added and the tube was placed on a
Butyl cinnamate (Table 2, entry 1)27
◦
shaking table overnight at 30 C. The glass tube was hereafter
Iodobenzene (40.8 mg, 0.20 mmol), n-butylacrylate (51.3 mg,
0.40 mmol), TBAB (64.5 mg, 0.40 mmol), Na2CO3 (53.0 mg,
0.50 mmol) and bio-Pd from C. necator suspensions (3 mg,
2 mmol) were added to a sample vial in a glovebox. DMF (2 mL)
was added and the sample vial was fitted with a teflon sealed
screwcap and removed from the glovebox. The reaction mixture
was heated to 80 ◦C for 12 h and then cooled to 20 ◦C; H2O was
added and the crude reaction was extracted with CH2Cl2. The
combined organic phases were washed with H2O and brine. The
organic phase was dried over MgSO4. After concentration in
vacuo, the crude product was purified by flash chromatography
on silica gel using CH2Cl2–pentane (1 : 1) as eluent affording
the title compound (39.7 mg, 97% yield) as a colourless oil. 1H
NMR (400 MHz, CDCl3) dH (ppm) 7.68 (d, 1H, J = 16.0 Hz),
7.54-7.52 (m, 2H), 7.39-7.37 (m, 3H), 6.44 (d, 1H, J = 16.0 Hz),
4.22 (t, 2H, J = 6.8 Hz), 1.73-1.66 (m, 2H), 1.49-1.40 (m, 2H),
0.97 (t, 3H, J = 7.3 Hz). 13C NMR (100 MHz, CDCl3) dC (ppm)
167.2, 144.7, 134.6, 130.3, 129.0 (2C), 128.2 (2C), 118.4, 65.6,
30.9, 19.3, 13.9. GCMS calcd C13H16O2 [M]: 204, found: 204.
centrifuged and the water was removed giving the bio-Pd, which
was used without further purification.
(E)-Butyl-3-(4-methoxyphenyl)acrylate (Scheme 1)27
1-Iodo-4-methoxybenzene (46.2 mg, 0.20 mmol), n-butyl-
acrylate (51.3 mg, 0.40 mmol), Na2CO3 (53.0 mg, 0.50 mmol),
TBAB (65.4 mg, 0.4 mmol) and bio-Pdwaste (15 mg, 10 mmol) were
added to a sample vial in a glovebox. DMF (2 mL) was added
and the sample vial was fitted with a teflon sealed screwcap and
removed from the glovebox. The reaction mixture was heated to
◦
◦
80 C for 24 h and then cooled to 20 C; H2O was added and
the crude reaction was extracted with CH2Cl2. The combined
organic phases were washed with H2O and brine. The organic
phase was dried over MgSO4. After concentration in vacuo, the
crude product was purified by flash chromatography on silica
gel using CH2Cl2–pentane (1 : 1) as eluent affording the title
1
compound (42.0 mg, 90% yield) as a colourless oil. H NMR
(400 MHz, CDCl3) dH (ppm) H NMR (400 MHz, CDCl3) d
1
(ppm) 7.63 (d, 1H, J = 15.9 Hz), 7.47 (d, 2H, J = 8.7 Hz),
6.90 (d, 2H, J = 8.2 Hz), 6.31 (d, 1H, J = 15.9 Hz), 4.20 (t,
2H, J = 6.9 Hz), 3.83 (s, 3H), 1.72-1.64 (m, 2H), 1.46-1.41 (m,
2H), 0.96 (t, 3H, J = 7.4 Hz). 13C NMR (100 MHz, CDCl3) dC
(ppm) 167.5, 161.4, 144.3, 129.8 (2C), 127.4, 115.9, 114.4 (2C),
64.4, 55.5, 30.9, 19.3, 13.9. GCMS calcd for C14H18O3 [M]: 234,
found: 234.
Recycling experiment
4-Iodotoluene (170.0 mg, 0.78 mmol), phenylboronic acid
(80.4 mg, 0.66 mmol), bio-Pd from C. necator suspensions
(20 mg, 14 mmol), Na2CO3 (190.8 mg, 1.8 mmol), TBAB
(386.8 mg, 1.2 mmol) were added to a sample vial in a glovebox.
EtOH (2 mL) and H2O (1 mL) were added and the sample
vial was fitted with a teflon sealed screwcap and removed from
the glovebox. The reaction◦mixture was heated to 50 ◦C for
24 h and then cooled to 20 C. The mixture was centrifugated
(10 min, 5000 rpm) and the supernatant was removed from the
pellet. The pellet was dissolved in EtOH (3 mL) and vortexed.
The mixture was hereafter centrifuged (10 min, 5000 rpm) and
the supernatant was removed from the pellet. The supernatants
were combined and concentrated in vacuo. The crude product
was purified by flash chromatography on silica gel using pentane
as eluent affording the product 4-methylbiphenyl. To the pellet
a new batch of substrates, TBAB, base and solvents were added
and the reaction was continued.
Acknowledgements
We thank Jacques Chevallier, Birte Lindahl Eriksen and Tove
Wiegers for their assistance with TEM, AAS and culturing,
and we gratefully acknowledge the Danish Research Council
for Technology and Production Sciences for funding this work.
Notes and references
1 Johnson Matthey, Platinum Met. Rev., 2008, 52, 198–199.
2 V. S. Baxter-Plant, A. N. Mabbett and L. E. Macaskie, Microbiology
Today, 2002, 29, 80–81.
3 V. S. Baxter-Plant, I. P. Mikheenko and L. E. Macaskie, Biodegrada-
tion, 2003, 14, 83–90.
4 A. N. Mabbett, P. Yong, J. P. G. Farr and L. E. Macaskie, Biotechnol.
Bioeng., 2004, 87, 104–109.
Preparation and treatment of the waste
The in-house generated waste was prepared from a hydrogena-
tion reaction of (E)-3-(4-methoxyphenyl)-N-methylacrylamide
(431.3 mg, 2.26 mmol) with Pd/C, 10% (120.0 mg, 5 mol%) in
a mixture of THF–H2O (10mL, 1 : 1) under an atmosphere of
hydrogen for 36 h at room temperature (rt). The solution was
concentrated in vacuo. In order to obtain a full oxidation of the
Pd, aqua regia (6 mL) was added slowly to the flask and the
solution was heated with a heat gun until boiling point. The
mixture was then left and stirred for 1 h at rt. To be tolerated
by the bacteria, the suspension was hereafter cooled to 0 ◦C on
an ice bath and neutralised to pH 7 using conc. NaOH solution.
This resulted in a Pd waste solution (0.11 mM, 20 mL). The
bacterial cell suspension (5 mL, OD600=1, C. necator) was added
5 A. C. Humphries, I. P. Mikheenko and L. E. Macaskie, Biotechnol.
Bioeng., 2006, 94, 81–90.
6 V. S. Baxter-Plant, I. P. Mikheenko, M. Robson, S. J. Harrad and
L. E. Macaskie, Biotechnol. Lett., 2004, 26, 1885–1890.
7 P. Yong, M. Paterson-Beedle, I. P. Mikheenko and L. E. Macaskie,
Biotechnol. Lett., 2007, 29, 539–544.
8 A. N. Mabbett and L. E. Macaskie, J. Chem. Technol. Biotechnol.,
2002, 77, 1169–1175.
9 P. Yong, N. A. Rowson, J. P. G. Farr, I. R. Harris and L. E. Macaskie,
J. Chem. Technol. Biotechnol., 2002, 77, 593–601.
10 I. de Vargas, L. E. Macaskie and E. Guibal, J. Chem. Technol.
Biotechnol., 2004, 79, 49–56.
11 A. N. Mabbett, D. Sanyahumbi, P. Yong and L. E. Macaskie, Environ.
Sci. Technol., 2006, 40, 1015–1021.
12 B. Mertens, C. Blothe, K. Windey, W. De Windt and W. Verstraete,
Chemosphere, 2007, 66, 99–105.
This journal is
The Royal Society of Chemistry 2009
Green Chem., 2009, 11, 2041–2046 | 2045
©

View Article Online
13 W. De Windt, N. Boon, J. Van Den Bulcke, L. Rubberecht, F. Prata,
J. Mast, T. Hennebel and W. Verstraete, Antonie van Leeuwenhoek,
2006, 90, 377–389.
14 W. De Windt, P. Aelterman and W. Verstraete, Environ. Microbiol.,
2005, 7, 314–325.
15 I. P. Mikheenko, M. Rousset, S. Dementin and L. E. Macaskie, Appl.
Environ. Microbiol., 2008, 74, 6144–6146.
16 Gram-negative bacteria possess a cell wall containing a thin layer of
peptidoglycans and an outer membrane composed of phospholipids
and lipopolysaccharides.
17 Gram-positive bacteria possess a cell wall composed of a thick
peptidglycan layer, and lack an outer membrane.
18 N. J. Creamer, I. P. Mikheenko, P. Yong, K. Deplanche, D.
Sanyahumbi, J. Wood, K. Pollmann, M. Merroun, S. Selenska-Pobell
and L. E. Macaskie, Catal. Today, 2007, 128, 80–87.
19 P. Yong, N. A. Rowson, J. P. G. Farr, I. R. Harris and L. E. Macaskie,
Biotechnol. Bioeng., 2002, 80, 369–379.
and Catalysts: Innovations in Organic Synthesis, J. Wiley & Sons,
Ltd., Chichester, 2000; (e) L. S. Liebeskind, in Advances in Metal-
Organic Chemistry, JAI press, Greenwich, 1996; (f) B. M. Trost, in
Comprehensive Organic Synthesis, Pergamon Press, New York, 1991;
(g) I. P. Beletskaya and A. V. Cheprakov, Chem. Rev., 2000, 100,
3009–3066; (h) W. A. Herrmann, V. P. W. Bo¨hm and C. P. Reisinger,
J. Organomet. Chem., 1999, 576, 23–41; (i) A. de Meijere and F. E.
Meyer, Angew. Chem., Int. Ed. Engl., 1994, 33, 2379–2411; (j) B. J.
Gallon, R. W. Kojima, R. B. Kaner and P. L. Diaconescu, Angew.
Chem., Int. Ed., 2007, 46, 7251–7254.
21 Protocol is described in detail in the ESI‡.
22 N. E. Leadbeater and M. Marco, J. Org. Chem., 2003, 68, 5660–5667.
23 The palladium amount in each reaction was difficult to determine
precisely. See ESI‡ for further information.
24 M. T. Reetz, R. Brainbauer and K. Wanninger, Tetrahedron Lett.,
1996, 37, 4499–4502.
25 A. B. Boricha, H. C. Bajaj, P. K. Ghosh and R. V. Jasra, Hydromet-
allurgy, 2007, 87, 140–147.
20 (a) J. Tsuji, in Palladium Reagents and Catalysis, New Perspectives For
the 21st Century, J. Wiley & Sons, Ltd., Chichester, 2004; (b) A. de
Meijere, F. Diederich, in Metal-catalysed Cross-coupling Reactions,
Wiley-VCH, Weinheim, 2nd edn, 2004; (c) E.-i Negishi, in Handbook
of Organopalladium Chemistry for Organic Synthesis, J. Wiley &
Sons, New York, 2002; (d) J. Tsuji, in Transition Metal Reagents
26 (a) F. Tsai, B. Lin, M. Chen, C. Mou and S. Liu, Tetrahedron, 2007,
63, 4304–4309; (b) A. Zapf and M. Beller, Chem.–Eur. J., 2000, 6,
1830–1833.
27 T. Mino, Y. Shirae, Y. Sasai, M. Sakamoto and T. Fujita, J. Org.
Chem., 2006, 71, 6834–6839.
2046 | Green Chem., 2009, 11, 2041–2046
This journal is
The Royal Society of Chemistry 2009
©