Synthesis of a novel polyaniline glycopolymer and its lectin binding studies

Article abstract of DOI:10.1071/CH13452

We report the multistep synthesis and polymerisation of a novel aniline derivative with a pendant α-d-mannose substituent. The α-D-mannose functionality was successfully introduced before polymerisation via copper-catalysed azide alkyne click chemistry an

Full text of DOI:10.1071/CH13452

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem. 2014, 67, 562–569
Full Paper
http://dx.doi.org/10.1071/CH13452
Synthesis of a Novel Polyaniline Glycopolymer
and its Lectin Binding Studies
A
A D
,
A
B
Christopher Wilcox, Jianyong Jin,
Hayley Charville, Simon Swift,
A
A
C
A
Teresa To, Paul A. Kilmartin, Clive W. Evans, Ralph Cooney,
and Margaret Brimble
A
A
School of Chemical Sciences, The University of Auckland, Private Bag 92019,
Auckland 1142, New Zealand.
B
Faculty of Medical and Health Sciences, The University of Auckland,
Private Bag 92019, Auckland 1142, New Zealand.
C
School of Biological Sciences, The University of Auckland, Private Bag 92019,
Auckland 1142, New Zealand.
D
Corresponding author. Email: j.jin@auckland.ac.nz
We report the multistep synthesis and polymerisation of a novel aniline derivative with a pendant a-D-mannose substituent.
The a-D-mannose functionality was successfully introduced before polymerisation via copper-catalysed azide alkyne
click chemistry and the resulting monomer was polymerised using general oxidative polymerisation conditions, producing
a water soluble mannosylated polyaniline. The polymer was characterised by several techniques and compared with
standard polyaniline. The selective binding of the polymer to Concanavalin A (ConA) was successfully demonstrated by
the precipitation of polymer–ConA aggregates. Potential applications of these novel polyaniline glycopolymers could
include the development of electroactive biomaterials with the ability to bind mannose receptors, or as sensors for proteins
or microbes.
Manuscript received: 30 August 2013.
Manuscript accepted: 1 November 2013.
Published online: 5 December 2013.
Introduction
polymers, such as polyaniline, being used as polymer back-
bones.[16–18] The advantages of polyanilines (PANI) include
intrinsic electrical conductivity, facile and inexpensive synthe-
sis, free radical scavenging action, and thermal stability up to
3008C.[19] By incorporating carbohydrate moieties into a poly-
aniline backbone, a synergistic interaction between the carbo-
hydrate and the corresponding lectin is expected. This
interaction could potentially induce a physicochemical change
in the properties of the polyaniline, e.g. its electrical conduc-
tivity, and therefore provide a useful tool that could be used
for sensing.[18]
Wang et al. have synthesised a mannose-functionalised
aniline monomer via successive electrochemical polymerisation
processes on an indium-doped tin oxide electrode.[18] The
sensing ability of this material was demonstrated by measuring
the interaction between ConA and the mannose-functionalised
polyaniline electrode that was characterised by electrochemical
impedance spectroscopy, UV–Vis spectroscopy, and cyclic
voltammetry. Li et al. reported the successful attachment of
quinone, cholic acid, iminodiacetic acid, and a carbohydrate
moiety to pyrrole through click chemistry.[17] These functiona-
lised pyrrole monomers were electropolymerised to produce
conducting glycopolymers. Gondran et al. attached a lactose
group to the polypyrrole backbone[16] and demonstrated
the application of these polypyrrole glycopolymers as sensors
and in surface plasmon resonance studies to evaluate the
Carbohydrate mimics are increasingly becoming a large and
interesting area of research for polymer scientists because of the
importance of carbohydrates in a wide variety of biological
communication events such as cellular recognition, inflamma-
tion, signal transmission, and the infection of pathogens.[1] For
instance, attachment of uropathogenic Escherichia coli occurs
via binding of the FimH protein to mannose or mannose-like
ligands on mucosal cells.[2–5] Further examples include the
binding of the influenza virus to N-acetylneuraminic acid resi-
dues on the target cells through haemagglutinin lectins, and also
the ability of anionic polysaccharides in inhibiting binding of the
human immunodeficiency virus to the host cell by blocking its
CD-4 receptors.[6]
Glycopolymers are synthetic polymers that comprise a
carbohydrate moiety, which enables recognition by surface
lectins on a cell.[7–12] The interactions between carbohydrates
and lectins can be greatly enhanced by the multivalent display of
the carbohydrate ligands along the polymer backbone, referred
to as the ‘cluster glycoside effect’, which is used in nature to
enhance the typically weak binding between a single lectin and
the carbohydrate.[13] The attachment of different carbohydrate
ligands can also impart selectivity to the glycopolymer because of
the specificaffinity of lectinreceptorsfortarget carbohydrates.[14]
Though many types of glycopolymers have been
reported,[7–12,15] there are relatively few examples of conducting
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Novel Polyaniline Glycopolymer
563
attachment of Maackia amurensis and Arachis hypogaea plant
lectins onto the lactosyl groups. These examples demonstrate
the great potential and possible applications of glycopolymers,
in particular conducting glycopolymers, as sensors; hence our
interest in this area of materials science.
In this work, we report the synthesis and polymerisation of a
novel mannose-functionalised aniline monomer, and its ability to
bind to mannose receptors. The carbohydrate moiety was deliv-
ered to aniline through a copper-catalysed azide alkyne click
(CuAAC) reaction. To the best of our knowledge, this is the first
example of a carbohydrate covalently bound to polyaniline
through click chemistry.
The cyclic voltammograms (CV) for the electropolymerisa-
tion of pure aniline and monomer 2 are shown in Fig. 1. The
voltammograms were obtained at a scan rate of 100 mV sꢀ1
Both aniline and monomer 2 exhibited a similar rise in the
.
(a) 1.4
NH2
1.2
1.0
0.8
0.6
0.4
709
490
0.2
0
228
Results and Discussion
661
Ϫ0.2
Ϫ0.4
Recently, click chemistry has been widely adopted by polymer
chemists as a simple and efficient way of combining two dif-
ferent functionalities.[20] The versatility of such a reaction in
multiple solvent systems, its applicability to various functional
groups, and its ability to give quantitative yields have generated
increasing research interest.[21] This concept was used in the
present study to develop a synthetic route to combine an azide-
functionalised mannose 1 to an alkyne-substituted aniline.
The azide-containing mannose intermediate 1 was synthe-
sized via a three-step procedure, as reported by Geng et al.
(Scheme 1), resulting in good-to-excellent yields at each
step.[22] The CuAAC process was then investigated. The substi-
tuted aniline monomer 2 was successfully prepared, with excel-
lent yield, under general CuAAC conditions. The copper(II)
sulphate pentahydrate-catalysed reaction of azide intermediate
1 with commercially available 2-ethynylaniline in the presence
of a reducing agent, sodium ascorbate, produced the desired
monomer 2, containing a 1,2,3-triazole spacer group, as a white
144
200
438
400
Ϫ200
0
600
800
1000
Potential [mV]
(b) 0.030
0.025
0.020
0.015
0.010
0.005
0
OAc
OAc
O
AcO
AcO
O
N
N
N
H
N
2
531
272
260
Ϫ0.005
477
Ϫ0.010
Ϫ200
0
200
400
600
800
1000
Potential [mV vs Ag/AgCl]
1
powder with a yield of 97 % (Scheme 2). Detailed H NMR,
13C NMR, and fourier transform infrared (FTIR) data are
available in the Supplementary Material section.
Fig. 1. Cyclic voltammograms of (a) aniline and (b) monomer 2, obtained
with a glassy carbon working electrode and Ag/AgCl reference electrode.
OAc
OAc
OAc
O
OAc
O
AcO
AcO
AcO
AcO
OH
OAc
2-Bromoethanol
BF3.OEt2
OH
O
OAc
O
I2(cat), Ac2O
NaN3 in DMF
AcO
AcO
HO
HO
O
O
DMF, 60ЊC, overnight
0ЊC to RT, 1h
DCM, 0ЊC to RT,
87 %
85 %
overnight
65 %
N3
Br
OH
OAc
1
Scheme 1.
OAc
OAc
O
OAc
AcO
AcO
OAc
O
R
R
R
R
1
1
1
1
NH
AcO
AcO
2
O
H
H
N
H
N
CuSO •5H O (5 mol-%)
Sodium ascorbate (10 mol-%)
4
2
N
N
N
O
ϩ
APS, aq HCl
20 %
ϩ
ϩ
ϩ
N
x
y
Ϫ
Cl
Ϫ
Cl
Ϫ
Cl
N
N
n
DMSO/H2O, 50ЊC, 3h
N
1
3
97 %
3
ES
2
H N
2
1 M NaOMe in MeOH
92 %
OH
OH
OAc
OAc
O
R
1 ϭ
R2 ϭ
O
HO
HO
AcO
AcO
R
R
R
2
R
2
2
2
O
O
H
N
H
N
H
N
N
N
x
y
N
N
n
N
N
4
EB
N
N
Scheme 2.

564
C. Wilcox et al.
anodic current at potentials greater than 900 mV, corresponding
to oxidation of the respective monomers.[23] The first oxidation
peak for the polymer formed from monomer 2 occurred at
272 mV; an associated broad cathodic peak for this process
was observed at 260 mV. These potential values were slightly
larger than those observed for pure polyaniline (i.e. 228 mV and
144 mV, respectively). This first set of redox peaks corresponds
to electron transfer between the fully reduced leucoemeraldine
and partially oxidized emeraldine forms of the electrodeposited
PANI film.[23] A second oxidation peak was observed at 531 mV
for the polymer formed from monomer 2, and relates to further
oxidation of the emeraldine to the fully oxidized pernigraniline
form of the polymer. This process occurred at a higher electrode
potential with regular polyaniline (peak at 709 mV). In the
polyaniline case, an additional set of intermediate peaks (oxida-
tion peak at 490 mV) was observed, which can be associated with
the occurrence of polymer over-oxidation processes at the
relatively high electropolymerisation potential, leading to
the formation of quinone derivatives or cross-linked phenazine
rings, which are electroactive in this potential range.[24,25] The
two main sets of redox peaks of monomer 2 are at closer
proximity when compared with those of pure aniline. This trend
is typical of substituted anilines.[26] PANI, a high-conducting
polymer, showed successive film layer formation in its CV, as
indicated by the higher current values for polymer redox pro-
cesses after each cycle. In contrast, this was not observed for
monomer 2, whereby polymer growth was limited. This indi-
cates that the resulting electrochemically deposited polymer 3 is
intrinsically poorly conductive and forms an insulating layer that
prevents further film formation. This difference in conductivity
is likely caused by a reduced degree of planarity in the structure
of the polyaniline because of the large D-mannose substituent[27]
and the electronic inductive effect exerted by the triazole group.
Following cyclic voltammetry study of the monomer to
determine the oxidative polymerisation reactivity, solution
polymerisation of monomer 2 was carried out under conven-
tional oxidative polymerisation conditions similar to those used
for the preparation of pure polyaniline. Ammonium persulphate
(APS) aqueous solution was used as the oxidant and was added
to a solution of monomer 2 in dilute aqueous HCl with a
monomer : oxidant molar ratio of 1 : 1.5. A dilute solution of
HCl was used to prevent the destruction of the pendant mannose
moieties during the polymerisation process. A cloudy solution
was obtained after 30 min. Formation of solid particles on the
glass wall of the reaction vessel was still not apparent following
a reaction time of 1 h. A dark coloured solution with obvious
solid formation was only obtained after the reaction was left
standing overnight. Polymer 3 was retrieved as a dark green–
black powder and showed film forming ability. However, the
yield of this polymerisation reaction was relatively low; an
average yield of ,20 % was obtained over five runs. The low
yield is likely because of the steric hindrance exerted by the
large pendant group.[27] Following isolation of polymer 3, the
acetyl protecting groups were removed from the mannose
functional group by adding a solution of polymer 3 in dimethyl-
formamide (DMF) to a solution of 1 M sodium methoxide
(NaOMe) in methanol to produce polymer 4. Polymer 4 was
then purified by dialysis against distilled water for two days
using a dialysis tubing with a molecular weight cut off (MWCO)
of 1000 Da. Polymer 4 was collected as a light brown powder
(92 % yield). The solubility properties of polymers 3 and 4 were
investigated; both polymers were completely soluble in metha-
nol, water, and N-methylpyrrolidone (NMP).
FTIR spectra of PANI EB (emeraldine base), and polymers 3
and 4 are shown in Fig. 2. The data were collected via
conventional KBr disks rather by the attenuated total reflectance
method as the refractive index of polyaniline-type materials is
similar to that of the diamond crystal. Polymer 3 displayed two
very broad peaks at 1755 and 1237 cmꢀ1, which were absent in
the FTIR spectra of polymer 4 and PANI. These peaks respec-
tively correspond to C¼O and C–O stretching vibration modes
from the acetyl protecting groups. These stretches were mostly
absent in the spectrum of polymer 4, thereby indicating that
deprotection of most of the pendant mannose groups on the
polymer was achieved. For polymer 4, the peaks at 1600 and
1450 cmꢀ1 correspond to the typical benzoid and quinoid ring
stretches of the polyaniline backbone, and are very similar to
those observed for pure polyaniline.[28,29] Notably, the peak at
1377 cmꢀ1 is considerably broader in the spectra of polymers 3
and 4 when compared with that observed in the spectrum of
PANI. This peak can be attributed to phenazine ring formation
and could indicate that a larger amount of phenazine formed for
the target polymers relative to pure PANI.[29] Characteristic
carbohydrate signals in the spectra of both polymer 3 and 4 were
evidenced by the C–O, C–C, and C–OH stretching vibrations in
the region of 1040–1150 cmꢀ1 [30,31]
1,2,3-Triazole rings are
.
expected to display characteristic absorbance peak at
,3130 cmꢀ1, however this is masked by the broad OH and
NH hydrogen bonding bands.[32,33]
UV–Vis spectroscopy is another useful characterisation
technique for PANI-type conducting polymers because of their
extended conjugation. The emeraldine base (EB) form of PANI
is significantly more soluble than the electrically conducting
emeraldine salt (ES) form. Figure 3 shows the UV–Vis spectra
of PANI, monomer 2, and polymers 3 and polymer 4 between
250 and 800 nm. Monomer 2 shows two absorption peaks at 260
and 325 nm, which correspond to the 1,2,3-triazole p–p*
transition and the benzene p–p* transition, respectively.[34]
The emeraldine base form of PANI shows two absorption peaks
at 325 nm and 630 nm. As noted earlier, the absorption at 325 nm
is due to the benzene p electrons. The other significant peak
at 630 nm corresponds to the single polaron formation.[35,36]
In comparison with monomer 2, polymers 3 and 4 showed
broader absorption bands, which are a good indication of the
presence of longer chain polymeric structures. The peak at
1237
1755
1462
1377
1512
1583
Polymer 3
1462
1371
1607
Polymer 4
Pure PANI
1502
1596
1377
4000
3000
2000
1000
Wavenumber [cmϪ1
]
Fig. 2. FTIR spectra of polymer 3, polymer 4, and PANI emeraldine base
(EB form).

Novel Polyaniline Glycopolymer
565
around 300 nm, as observed in the spectrum of polymer 3, but
which is absent in polymer 4, could correspond to the acetyl
protecting groups. Polymers 3 and 4 both showed a peak at
,400 nm that was absent in the spectra of the monomer and
PANI; the observed peak could be due to phenazine structures
formed as a by-product. A very weak broad band around 580 nm,
which was observed in the spectrum of pure PANI, was also
noted herein. However, it was blue shifted. The blue shift of the
band may be an indication of the presence of shorter polymer
chains, and generally occurs with decreased conjugation length.
Gel permeation chromatography (GPC) was conducted on
the acetyl-protected polymer 3 to measure its molecular weight.
The sample was examined in NMP because of the high solubility
of the polymer and PANI in this solvent. Multi-angle laser light
scattering data could not be collected because conducting
polymers, e.g. polyaniline, strongly absorb light at the operating
wavelengths of the detectors.[37] The GPC trace (Supplementary
Material, Fig. S4) showed a bimodal distribution at ,22500 and
,1000, corresponding to the larger and lower Mws; the data
were collected over two runs and averaged. The data agree with
both the FTIR and UV–Vis results, indicating the possible
existence of phenazine oligomers, which formed by head-to-
head polymerisation rather than the favoured head-to-tail fash-
ion. Compared with the reduced sterically hindered aniline
polymerisation, the large mannose pendant substituent group
in the ortho-position of the aniline blocks the polymerisation
pathway and hinders the preferred head-to-tail positioning.
ConA was chosen as the model a-mannose binding lectin
because it shows well-documented binding to various mannose
structures and is also similar to many animal and bacterial
lectins in cell communications.[38,39] In a recent paper by Wang
et al.,[18] the authors successfully demonstrated the extreme
sensitivity and selective binding of a novel mannosylated
polyaniline to the target lectin. To confirm the biological
activity of polymer 4 as synthesised herein, a solution-based
ConA assay[40] was selected to investigate binding (see detailed
procedure in the Experimental section). This assay was con-
ducted by incubating polymer 4 solutions of different concen-
trations with a solution of ConA at room temperature for 12 h.
Figure 4a, b shows macroscopic confirmation of the binding, as
indicated by precipitate formation, presumably polymer–ConA
aggregates, following introduction of polymer 4 to the solution
of ConA. Subsequently, the dissolution of the precipitate upon
addition of methyl a-D-mannopyranoside ligand, which com-
petes for binding sites on ConA, is demonstrated (Fig. 4).
The precipitate (pellet) resulting from the interaction of the
polymer with ConA could be separated from the supernatant by
centrifugation and redissolved in a methyl a-D-mannopyrano-
side solution for UV–Vis measurements at 280 nm. Figure 5
shows the results of the assay whereby an increase in the ConA
content in the pellet was observed when the concentration of
polymer 4 increased. Ideally, we would expect a decrease of the
260
300
3
4
325
400
630
EB
2
580
300
400
500
600
700
800
Wavelength [nm]
Fig. 3. UV–Vis spectra of monomer 2, polyaniline EB, polymer 3, and
polymer 4 in NMP.
Methyl-α-D-
mannopyranoside
OH
OH
O
ConA
HO
ConA
HO
O
OH
OH
O
HO
HO
N
N
N
O
N
N
N
PANI vertebra
PANI vertebra
De-binding
Binding
(b)
(a)
Fig. 4. Schematic representation of ConA–polymer binding and de-binding. Optical images show (a) the precipitate formed by
interaction of polymer 4 with ConA and (b) the clear solution obtained after addition of a-D-mannopyranoside. Both solutions
were allowed to stand for 1 h following addition and centrifugation.

566
C. Wilcox et al.
2.5
2.0
1.5
1.0
0.5
0
0
100
200
300
400
500
600
700
800
900
Polymer concentration [μg mLϪ1
]
Amount of ConA bound to polymer (i.e. amount of ConA in pellet)
Amount of ConA that did not bind to the polymer (i.e. amount of ConA in supernatant)
Fig. 5. ConA assay results that describe the presence of ConA in the pellet and the supernatant solution as a function of polymer
concentration.
ConA absorbance in the supernatant layer upon precipitation by
polymer 4. An initial drop in the ConA absorbance was
observed. However, after adding 200–300 mg mLꢀ1 of polymer
4, the supernatant absorbance signal increased again, likely
because of the strong absorption of excess polymer 4 at 280 nm.
emeraldine salt forms were prepared in-house according to
standard synthesis procedures.[41]
1,2,3,4,6-Penta-O-acetyl-a-D-mannopyranoside
D-mannose (7 g, 38.9 mmol) was gradually added (in five
portions) to a stirred solution of iodine (0.4 g, 1.55 mmol) in
acetic anhydride (40 mL, 432 mmol) at 08C. The reaction
mixture was allowed to stir at this temperature for 30 min and
then allowed to warm up to room temperature. After 1 h at room
temperature, methanol (20 mL) was added and the mixture was
stirred for a further 30 min, followed by evaporation of the
solvent under vacuum. The residue was dissolved in dichlor-
omethane (DCM; 50 mL) and washed with Na2S2O5 solution
(2 ꢁ 50 mL). The layers were separated and the resulting colour-
less organic phase was washed with NaHCO3 solution
(4 ꢁ 50 mL), dried (MgSO4), and concentrated under reduced
pressure to afford a pale yellow oil (12.9 g, 85 %) as an anomeric
Conclusion
We have reported the synthesis of a pendant a-D-mannose
moiety attached to aniline through a copper-catalysed azide
alkyne click (CuAAC) reaction, and subsequent polymerisation
of the monomer via chemical oxidative processes. Cyclic vol-
tammetry and UV–Vis spectroscopy were used to characterise
the electronic and spectroscopic properties of the resulting
monomer and polymers, and their similarities to pure PANI
were investigated. FTIR studies confirm polymerisation of
monomer 2, as indicated by the prominent benzoid and quinoid
peaks, and also retention of the mannose moiety signals. A
phenazine-type by-product was also observed, which is con-
sistent with the bimodal GPC data. ConA assay demonstrates the
ability of polymer 4 to interact with ConA lectins and provides
foundation for future work, which will include investigating the
ability of this polymer to bind and probe bacteria, in particular
Escherichia coli. Preparation of the polymer with a higher
molecular weight and yield will also be examined.
1
mixture (a : b, 4 : 1), as determined by H NMR. The product
was used in the next step without any further purification.
dH (400 MHz, CDCl3) 1.97 (s, 3H, OC(O)CH3), 2.02 (s, 3H,
OC(O)CH3), 2.06 (s, 3H, OC(O)CH3), 2.14 (s, 3H, OC(O)CH3),
2.15 (s, 3H, OC(O)CH3), 4.01–4.13 (m, 2H, CH2OAc), 4.23–
4.29 (m, 1H, CH), 5.22–5.32 (m, 3H, 3 ꢁ CH), 6.05 (d, J 1.9, 1H,
CH). Resonances for minor b anomer: dH (400 MHz, CDCl3)
2.00 (s, 3H, OC(O)CH3), 2.07 (s, 3H, OC(O)CH3), 2.18 (s, 3H,
OC(O)CH3), 3.77–3.81 (m, 1H, CH), 5.10 (dd, J 6.6, 3.4, 1H,
CH), 5.43–5.46 (m, 1H, CH), 5.83 (d, J 1.2, 1H, CH). Data were
consistent with that reported in the literature.[42]
Experimental
Materials
Unless stated otherwise, all solvents and reagents were used as
supplied from commercial sources. All moisture sensitive
reactions were performed in oven-dried glassware under an
inert, dry nitrogen atmosphere. Analytical thin layer chroma-
tography was performed using Kieselgel F254 0.2 mm silica
plates (Merck), and the plates were visualised under ultraviolet
irradiation (254 nm) and/or by staining with vanillin. Flash
chromatography was performed using Kieselgel S 63–100 mm
silica gel (Riedel-de-Hahn). The solvent compositions used for
all chromatographic separations are reported on a (v/v) basis.
Spectra/Por Dialysis Membrane MWCO 1000 was used as the
dialysis tubing. Polyaniline in both emeraldine base and
2-Bromoethyl 2,3,4,6-tetra-O-acetyl-
a-D-mannopyranoside
Boron trifluoride diethyl etherate (BF3 ꢂ Et2O; 7.9 mL,
64.05 mmol) was added dropwise to a solution of 1,2,3,4,6-
penta-O-acetyl-a-D-mannopyranoside (5 g, 12.81 mmol) and
2-bromoethanol (1.82 mL, 25.62 mmol) in dry DCM (80 mL)
at 08C. After 1 h, the ice bath was removed and the reaction was
continued at room temperature overnight. The reaction mixture
was then slowly added to cold water (80 mL) and the organic
layer was separated. The aqueous layer was extracted with DCM
(50 mL) and the organic layers combined and washed

Novel Polyaniline Glycopolymer
567
successively with water (100 mL), saturated NaHCO3
(2 ꢁ 100 mL), and water (100 mL). The solution was dried over
MgSO4 and concentrated under reduced pressure to afford a
yellow oil. The product was precipitated from diethyl ether to
produce a white powder that was filtered, washed with diethyl
ether, and dried under high vacuum (4.03 g, 65 %). dH
(400 MHz, CDCl3) 1.99 (s, 3H, OC(O)CH3), 2.05 (s, 3H, OC
(O)CH3), 2.11 (s, 3H, OC(O)CH3), 2.16 (s, 3H, OC(O)CH3),
3.50–3.53 (m, 2H, CH2Br), 3.79–3.91 (m, 2H, OCH2), 4.10–4.15
(m, 2H, CH2OAc), 4.24–4.29 (m, 1H, CH), 4.87 (d, J 1.7, 1H,
CH), 5.26–5.33 (m, 3H, 3 ꢁ CH). dc (100 MHz, CDCl3) 20.6,
20.7, 20.8, 20.9 (CH3), 29.6 (CH2Br), 62.4 (CH2OAc), 66.0,
68.5, 68.9 (CH), 69.0 (OCH2CH2Br), 69.4 (CH), 97.8 (CH),
169.7, 169.8, 170.0, 170.6 (OC(O)CH3). Data are consistent
with that reported in the literature.[22]
20.6, 20.7, 20.8 (CH3), 49.8 (CH2CH2N), 62.1 (CH2CH2N), 65.4
(CH), 65.8 (CH2OAc), 68.9 (2 ꢁ CH), 69.2 (CH), 96.9 (CH),
113.4 (ArC), 116.7 (ArC), 117.4 (ArC), 121.2 (triazole-CH),
128.0 (ArC), 129.0 (ArC) 145.1 (ArCNH2), 148.7 (triazole-C),
169.7, 169.9, 170.0, 170.5 (OC(O)CH3). m/z (ESI) 535.2
[MþH]þ. HRMS (ESI) C24H30N4O10 requires 557.1854
[MþNa]. Found: 557.1849 [MþNa].
Synthesis of Polymer 3
Polymerisation was conducted using the general oxidative
polymerisation procedure as employed for the synthesis of
aniline. Monomer 2 (100 mg, 0.187 mmol) was weighed into a
beaker and HCl (0.05 M, 5 mL) was added. The resulting mix-
ture was sonicated for five minutes to ensure complete disso-
lution. Ammonium persulphate (APS) (64.07 mg, 0.281 mmol)
was weighed into a separate beaker and completely dissolved in
HCl (0.05 M, 0.5 mL). The APS solution was then added to the
solution containing monomer 2. The resulting solution was
briefly stirred and then allowed to stand at room temperature.
A dark green–black precipitate was obtained after 24h.
The precipitate and remaining solution were poured into a 50-mL
centrifugetubeand distilled water was usedtoensure quantitative
transfer. The sample was then centrifuged at 2500 g for 15 min
at room temperature. The supernatant was decanted and distilled
water (20 mL) was added. Re-suspension of the precipitate was
conducted by vortex. The washing process was repeated thrice.
The precipitate was then dried in a vacuum oven at 408C over-
night to afford a dark powder (20 % average yield).
20Azidoethyl 2,3,4,6-tetra-O-acetyl-
a-D-mannopyranoside (1)
2-Bromoethyl 2,3,4,6-tetra-O-acetyl-a-D-mannopyranoside
(2 g, 4.4 mmol) and sodium azide (2.28 g, 35.12 mmol) were
dissolved in dry DMF (60 mL) and the reaction was stirred under
N2 at 608C for 6 h before cooling to room temperature and
stirring overnight. The reaction mixture was then poured into
ethyl acetate (150 mL) and washed with water (3 ꢁ 100 mL) and
brine (2 ꢁ 100 mL). The organic layer was dried (MgSO4),
filtered, and concentrated under vacuum. The crude product
was purified by silica gel column chromatography (ethyl ace-
tate : hexane, 2 : 1) to afford product 1 as white crystals (1.59 g,
87 %). dH (400 MHz, CDCl3) 1.99 (s, 3H, OC(O)CH3), 2.05
(s, 3H, OC(O)CH3), 2.12 (s, 3H, OC(O)CH3), 2.16 (s, 3H,
OC(O)CH3), 3.46–3.49 (m, 2H, OCH2CH2N3), 3.65–3.70
(m, 1H, OCH2CH2N3), 3.85–3.89 (m, 1H, OCH2CH2N3),
4.02–4.15 (m, 2H, CH2OAc), 4.27–4.31 (dd, J 5.4, 12.1, 1H,
CH), 4.87 (d, J 1.5, 1H, CH), 5.27–5.35 (m, 3H, 3 ꢁ CH).
dc (100 MHz, CDCl3) 20.6, 20.7, 20.7, 20.9 (CH3), 50.5
(OCH2CH2N3), 62.5 (OCH2CH2N3), 66.0 (CH), 67.0
(CH2OAc), 68.9 (CH), 69.4 (CH), 97.8 (CH), 169.8, 169.9,
170.2, 170.8 (OC(O)CH3). Data are consistent with that reported
in the literature.[43]
Synthesis of Polymer 4
The resulting polymer 3 was deprotected using sodium meth-
oxide. A solution containing sodium methoxide (0.1 M) in
methanol was prepared. Polymer 3 (10 mg) that was dissolved in
DMF (1 mL) was then added to this solution (0.2 mL). The
reaction proceeded for 24 h after which cold diethyl ether
(30 mL) was added dropwise, producing a brown precipitate.
This mixture was centrifuged (2500 g, 5 min, room temperature)
and the ether was decanted. The washing process with ether was
repeated thrice. The final product was dialysed against distilled
water for two days using a dialysis tubing with a MWCO of
1000. Finally, the product was freeze-dried to afford a brown
powder (92 % yield).
Synthesis of Monomer 2
Copper(II) sulphate pentahydrate (23 mg, 0.0935 mmol), sodium
ascorbate (37 mg, 0.187 mmol), and 2-ethynylaniline (0.26 mL,
2.25 mmol) were dissolved in water (20 mL) and heated at 508C
under a N2 atmosphere for 10 min. 20Azidoethyl 2,3,4,6-tetra-O-
acetyl-a-D-mannopyranoside (1.00 g, 1.87 mmol) in DMSO
(40 mL) was added to the solution and the mixture was left to stir
at 508C for 3 h. The reaction mixture was then diluted with DCM
(50 mL) and washed with brine (4 ꢁ 50 mL), dried (MgSO4),
filtered, and concentrated under vacuum. The crude product was
purified by silica gel column chromatography (ethyl acetate :
hexane, 6 : 1) to afford product 2 as a white solid that was dried
under high vacuum (973 mg, 97 %), mp 54–578C. [a]2D0 40.7
(c 0.26 g/100 mL in MeOH). nmax (KBr)/cmꢀ1 755, 977, 1042s,
1087, 1136, 1221s, 1368, 1442, 1618, 1741s, 3456w. dH
(400 MHz, CDCl3) 1.77 (s, 3H, OC(O)CH3), 1.99 (s, 3H, OC(O)
CH3), 2.07 (s, 3H, OC(O)CH3), 2.13 (s, 3H, OC(O)CH3),
3.14–3.17 (m, 1H, CH), 3.88–3.98 (m, 2H, CH2CH2N),
4.07–4.17 (m, 2H, CH2CH2N), 4.58–4.72 (m, 2H, CH2OAc),
4.82 (d, J 0.8, 1H, CH), 5.15–5.19 (m, 3H, 3 ꢁ CH), 6.68–6.75
(m, 2H, 2 ꢁ ArH), 7.07–7.11 (m, 1H, ArH), 7.42 (dd, J 1.4, 7.8,
1H, ArH), 7.93 (s, 1H, triazole-H). dc (100 MHz, CDCl3) 20.2,
Characterisation
1H NMR spectra were recorded on a 400 MHz Bruker spec-
trometer and the data are reported in parts per million (ppm) on
the d scale relative to CDCl3 (d 7.26); 13C NMR spectra were
recorded on a 100 MHz Bruker spectrometer and the data are
reported in parts per million (ppm) on the d scale relative to
1
CDCl3 (d 77.16). The multiplicities of the H signals are des-
ignated by the following abbreviations: s ¼ singlet; d ¼ doublet;
t ¼ triplet; q ¼ quartet; m ¼ multiplet; br ¼ broad; dd doublet of
doublets; dt ¼ doublet of triplets; and dm ¼ doublet of multi-
plets. All coupling constants, J, are reported in hertz.
Cyclic voltammetry was conducted on a BAS100B electro-
chemical analyser using a three-electrode setup comprising a
glassy carbon working electrode, platinum counter electrode,
and Ag/AgCl reference. The experiments started at a potential of
ꢀ200 mV that increased to 1000 mV at a scan rate of 100 mV sꢀ1
and a sensitivity of 10 mA Vꢀ1. The solutions for the electro-
chemical polymerisation were 0.1 M of monomer in 0.5 M
H2SO4 supporting electrolyte. All electropolymerisation

568
C. Wilcox et al.
solutions were degassed under oxygen-free nitrogen for at least
15 min before use.
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FTIR was conducted as KBr disks on a Thermo Nicolet 8700
FTIR spectrophotometer. KBr was dried in an oven at 1008C
before use. The disks were prepared with 150–200 mg of KBr
and 1 mg of polymer. The powders were combined and ground
in a mortar and pressed under 5 tons of pressure for 5 min in a
pellet press.
UV–Vis spectra were collected on a Shimadzu UV-2101PC
UV–Vis scanning spectrophotometer. NMP was used as the
solvent.
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Gel permeation chromatography (GPC) was used for poly-
mer molecular weight measurements. The system consisted of a
Waters 515 HPLC pump, a Degassex DG-4400 on-line degasser
connected to a TSK Gel Super AWM-H column (9 mm,
6 ꢁ 150 mm) with guard, 0.5-mm in-line filters, a Rheodyne
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detector were maintained at 358C.
Concanavalin A (ConA) is a bindinglectin from the jack bean
Canavalia ensiformis. The procedure used for the ConA assay is
as follows[40]: a buffer solution (0.1 M tris-HCl pH 7.2, 0.9 M
NaCl, 1 mM CaCl2, 1 mM MnCl2) was prepared and used to
dissolve all solids including ConA and polymer 4. All mixtures
were placed on a vortex for 5 min to achieve complete dissolu-
tion, and centrifuged (2500 g, 2 min, room temperature) to
remove residual solids. The polymer stock solution was pre-
pared by dissolving polymer 4 (4 mg) in the buffer solution
(400 mL). This stock solution was diluted to achieve the follow-
ing polymer solutions at concentrations of 800, 700, 600, 500,
400, 300, 200, 100, 50, and 0 mg mLꢀ1. A separate ConA stock
solution was prepared by dissolving ConA (30.42 mg, 90 mM,
assuming ConA tetramer with a molecular weight of 104000 Da)
in the buffer solution (1.63 mL). Each polymer sample (125 mL)
was mixed with ConA solution (125 mL) and left overnight. The
solution was then centrifuged (2500 g, 2 min, room temperature)
and the supernatant was removed using a pipette. The precipitate
(pellet) was then redissolved in methyl a-D-mannopyranoside
(1 M, 1 mL). UV–Vis measurements of the supernatant solution
containing the pellet were conducted at 280 nm in a quartz
cuvette; an average of two scans were taken.
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Acknowledgements
This research was financially supported by the New Zealand Ministry of
Business, Innovation and Employment through the Hybrid Polymers Pro-
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