Surface modification of polymers with bis(arylcarbene)s from bis(aryldiazomethane)s: preparation, dyeing and characterization

Article abstract of DOI:10.1039/C6RA24392D

Modification of polymer beads by bis(arylcarbene) insertion provides access to materials with similar bulk properties, but different surface chemical characteristics, compared to the unmodified polymer. A subsequent dyeing process using different diazonium salts generates colored polymers with a variety of surface functional groups. XPS and solid state NMR spectra were used to characterize modified and dyed polymers, which showed this protocol was both successful and general. BET data showed that the surface area changed significantly after modification, while BJH data showed pore size distribution was unchanged. TG/DSC analysis and Elemental Analysis were also used to characterize modified polymers. This permitted calculation and comparison of the loadings of surface area and the modification effects with different chemical structure of bis(arylcarbene)s. This work shows that the bis(arylcarbene) system is as effective as mono(arylcarbene)s, but of significance since the starting bis(aryldiazomethane)s are more easily accessible and easier to handle than the mono(aryldiazomethane)s. All this data indicates that the surface property of polymers is modified.

Full text of DOI:10.1039/C6RA24392D

RSC Advances
View Article Online
View Journal | View Issue
PAPER
Surface modification of polymers with
bis(arylcarbene)s from bis(aryldiazomethane)s:
Cite this: RSC Adv., 2016, 6, 111276
preparation, dyeing and characterization†
Pengfei Yang and Mark G. Moloney*a
ab
Modification of polymer beads by bis(arylcarbene) insertion provides access to materials with similar bulk
properties, but different surface chemical characteristics, compared to the unmodified polymer. A
subsequent dyeing process using different diazonium salts generates colored polymers with a variety of
surface functional groups. XPS and solid state NMR spectra were used to characterize modified and dyed
polymers, which showed this protocol was both successful and general. BET data showed that the
surface area changed significantly after modification, while BJH data showed pore size distribution was
unchanged. TG/DSC analysis and Elemental Analysis were also used to characterize modified polymers.
This permitted calculation and comparison of the loadings of surface area and the modification effects
with different chemical structure of bis(arylcarbene)s. This work shows that the bis(arylcarbene) system is
as effective as mono(arylcarbene)s, but of significance since the starting bis(aryldiazomethane)s are more
easily accessible and easier to handle than the mono(aryldiazomethane)s. All this data indicates that the
surface property of polymers is modified.
Received 30th September 2016
Accepted 16th November 2016
DOI: 10.1039/c6ra24392d
www.rsc.org/advances
1
. Introduction
Carbenes, which could be generated from diazomethanes by UV
1
light or by heating, are widely used for organic synthesis and
2–5
polymerization, as well as other important applications in
Scheme 1
6,7
8
photoresponsive behavior, ESR measurement, and organo-
9,10
magnetic metals. By comparison, the application of carbenes
for the modication of synthetic polymers has been much
and payload delivery properties to a wide range of synthetic
polymers.
11–13
rarer.
Thus, since methodology for the modication oen
required volatile and highly reactive carbenes, high temperature
and metal catalysts, carbene insertion has been largely over-
In order to further explore our protocol and increase the
surface loadings which can be achieved by introducing an
element of crosslinking, a series of bis(aryldiazomethane)s with
different functional groups were synthesized, which was never
reported before. These bis(aryldiazomethane)s were used to,
14
looked as a method for polymer modication. Recently,
15–17
18
Hayes
and Ragogna reported a protocol using carbenes
that are generated from diazirines for the surface modication
of polymers. In contrast to their approach, we have developed
a new strategy of carbene insertion derived from aryldiazo-

rstly, modify polymers, and secondly, allow azo coupling
reactions with different diazonium salts, which introduced
easily detected elements and permit access to polymers with
modied surface but unchanged bulk properties. Surface
loadings were determined according to the BET data and the
Elemental Analysis data, which showed that the method of
synthesis, modication and dyeing was reliable and signicant.
19–26
methanes,
which is attractive for polymer modication
because of the short synthetic route and mild reaction condi-
tions. Highly reactive arylcarbene intermediates could be easily
generated under heating conditions (Scheme 1), and could be
used to introduce color, uorescence, biocompatibility, biocidal
2
. Experimental section
a
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, OX1
3
TA, UK. E-mail: mark.moloney@chem.ox.ac.uk
2.1 Materials
b
School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology,
Jinan 250353, P. R. China
1
1
,3-Phenylenebis((4-phenoxyphenyl)methanone)
,4-phenylenebis((4-phenoxyphenyl)methanone)
(1,3-EKKE),
(1,4-EKKE),
†
Electronic supplementary information (ESI) available. See DOI:
0.1039/c6ra24392d
1
and
naphthalene-2,6-diylbis((4-phenoxyphenyl)methanone)
111276 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
(

EKNKE) were obtained from Ketonex Ltd. 1H,1H,2H,2H-Per- (84%) of a white solid as a mixture of diastereoisomers was used
ꢀ
uorooctyl iodide and 1H,1H,2H,2H-peruorododecyl iodide without further purication. Mp: 225–227 C; d (500.3 MHz,
H
were purchased from Fluorochem Ltd. Other commercial DMSO-d6): 6.34 (s, 2H), 6.44 (s, 2H), 6.93–7.04 (m, 4H), 7.09–
reagents were purchased from Sigma-Aldrich Co. Two polymer 7.25 (m, 6H), 7.30 (m, 2H), 7.35–7.49 (m, 8H), 7.70 (d, 1H), 7.83
beads, XAD4 and MAC-3, was purchased from Sigma-Aldrich Co (d, 1H), 7.94 (s, 1H), 8.18 (d, 1H); d (125.8 MHz, DMSO-d6):
C
and used as received. XAD4 is composed of polystyrene that is 118.9, 119.0, 119.3, 119.6, 119.7, 124.0(d), 124.2, 124.4, 124.8,
crosslinked with divinylbenzene, and is hereinaer referred to 127.3, 127.7, 128.2, 128.3, 128.6, 129.2, 129.9, 130.5, 130.6,
as polystyrene beads. Polystyrene beads are mesoporous with 131.3, 132.0, 132.6, 133.5, 134.9, 137.1, 144.1, 144.2, 156.5,
ꢁ
1
large surface area and their size is 20–60 mesh. MAC-3 is 156.7, 157.1, 157.4; IR nmax (cm ): 3394, 3357, 3273, 3062, 1587,
composed of polyacrylate with some carboxyl groups on the 1501, 1486, 1235, 1168, 1067; HRMS: m/z calcd for C H O N :
3
6
29 2 4
+
surface, and is hereinaer referred to as polyacrylate beads. 549.22850; found: 549.22812 [M + H] .
0
0
Polyacrylate beads are macroporous without large surface area
and their size is 12–50 mesh.
2.2.4 4,4 -((((1E,1 E)-1,3-Phenylenebis(hydrazonomethylene))
bis(4,1-phenylene))bis(oxy))dianiline (2d). A suspension of 1d
(
0.36 g, 0.51 mmol) in ethanol (7 ml) was treated with hydrazine
hydrate (0.51 ml, 10.2 mmol). A few drops of acetic acid (about
.2 ml) were added as catalyst. The resulting mixture was heated
.2.1 1,3-Phenylenebis((4-phenoxyphenyl)methanone) hydra to a gentle reux for 40 h. Aer cooling, the solution was
zone (2a). A suspension of 1,3-EKKE 1a (0.25 g, 0.53 mmol) in evaporated under vacuum. The residue was dissolved in DCM
ethanol (7 ml) was treated with hydrazine monohydrate (50 ml), washed with water (50 ml ꢂ 4), dried with MgSO , and
0.52 ml, 10.6 mmol). A few drops of acetic acid (about 0.2 ml) evaporated under vacuum. The crude product 2d (87%) of
2.2 Synthesis of hydrazones
0
2
4
(
were added as catalyst. The resulting mixture was heated to a white solid as a mixture of diastereoisomers was used without
ꢀ
a gentle reux for 40 h. Aer the mixture was cooled, water (50 further purication. Mp: 92–96 C; d
H
(500.3 MHz, CDCl
3
): 3.52
ml) was added, giving a suspension. The mixture was ltered (s, 4H), 5.43 (s, 4H), 6.52–6.64 (m, 4H), 6.70–6.85 (m, 6H), 6.89–
and the precipitate was dried in an oven. The crude product 2a 6.96 (m, 2H), 7.05–7.13 (m, 3H), 7.25–7.60 (m, 5H); d (125.8
): 116.2, 116.3, 116.8, 117.5, 117.6, 121.2, 121.3,
C
(
77%) of a light yellow solid as a mixture of diastereoisomers MHz, CDCl
3
ꢀ
was used without further purication. Mp: 60–62 C; d
H
(500.3 121.6, 121.7, 124.7, 125.5, 126.0, 126.4, 126.5, 127.1, 127.8,
127.9, 128.3, 129.3, 129.4, 130.3, 132.3, 132.5, 133.0, 134.4,
125.8 MHz, DMSO-d6): 118.7, 118.8, 119.1(d), 119.5(d), 119.6, 138.7, 140.0, 142.9, 143.0, 143.3, 143.4, 147.4, 147.6, 147.8,
MHz, DMSO-d6): 6.16–6.54 (m, 4H), 6.90–7.56 (m, 22H); d
C
(
1
1
1
1
19.7, 123.3, 123.9, 124.3, 124.4, 125.0, 125.9, 126.2, 127.5, 148.1, 148.3, 148.8, 149.1, 159.1, 159.3, 159.5, 159.7; IR nmax
27.6, 127.8, 127.9, 128.3(d), 129.6, 129.8, 130.5, 130.6, 130.8, (cm ): 3353, 3210, 3038, 1603, 1495, 1228, 1198, 1165; HRMS:
ꢁ1
31.1, 131.2, 133.3, 134.7, 134.8, 135.0, 139.3, 140.6, 143.3, m/z calcd for C32
H
29
O
2
N
6
: 529.23465; found: 529.23431 [M +
+
43.4, 144.2, 144.4, 156.5(d), 156.7, 157.0, 157.2, 157.4; IR nmax H] .
ꢁ1
0 0
(
cm ): 3403, 3039, 2922, 1586, 1502, 1486, 1232, 1164, 1070;
2.2.5 4,4 -((((1Z,1 Z)-1,4-Phenylenebis(hydrazonomethylene))
HRMS: m/z calcd for C32
H
27
O
2
N
4
: 499.21285; found: 499.21291 bis(4,1-phenylene))bis(oxy))dianiline (2e). A suspension of 1e
+
[M + H] .
(0.36 g, 0.51 mmol) in ethanol (7 ml) was treated with hydrazine
2
.2.2 1,4-Phenylenebis((4-phenoxyphenyl)methanone) hydra hydrate (0.51 ml, 10.2 mmol). A few drops of acetic acid (about
zone (2b). A suspension of 1,4-EKKE 1b (0.25 g, 0.53 mmol) in 0.2 ml) were added as catalyst. The resulting mixture was heated
ethanol (7 ml) was treated with hydrazine monohydrate to a gentle reux for 40 h. Aer cooling, the mixture was ltered
(0.52 ml, 10.6 mmol). A few drops of acetic acid (about 0.2 ml) and the precipitate was dried in an oven. The crude product 2e
were added as catalyst. The resulting mixture was heated to (86%) of a white solid as a mixture of diastereoisomers was used
ꢀ
a gentle reux for 40 h. Aer cooling, the mixture was ltered without further purication. Mp: 106–110 C; d
H
(400.3 MHz,
and the precipitate was dried in an oven. The crude product 2b DMSO-d6): 5.01 (d, 4H), 6.05–6.45 (m, 4H), 6.55–6.67 (m, 4H),
(
82%) of a white solid as a mixture of diastereoisomers was used 6.72–6.89 (m, 6H), 6.97–7.06 (m, 2H), 7.10–7.30 (m, 6H), 7.32–
ꢀ
without further purication. Mp: 181–184 C; d
H
(500.3 MHz, 7.56 (m, 2H); d
C
(100.6 MHz, DMSO-d6): 115.3, 115.4, 116.6,
DMSO-d6): 6.33 (s, 4H), 7.09–7.25 (m, 14H), 7.28 (s, 4H), 7.44 (t, 117.4, 117.5, 121.3, 121.4, 121.7(d), 125.7, 126.3, 126.5, 126.7,
4
1
3
6
4
H); dC (125.8 MHz, DMSO-d6): 119.6(d), 124.3, 125.7, 128.3, 127.4, 127.5, 129.0, 130.2, 130.8, 130.9, 132.3, 133.3, 138.4,
ꢁ
1
30.6, 131.1, 138.3, 144.1, 156.7, 157.3; IR nmax (cm ): 3378, 139.6, 143.8, 144.4, 144.8, 145.4(d), 145.9, 146.0, 146.3(d), 158.9,
ꢁ
1
276, 3038, 1588, 1503, 1488, 1250, 1164, 1070, 872, 840, 755, 159.5, 159.6; IR nmax (cm ): 3423, 3348, 3037, 1603, 1496, 1237,
91; HRMS: m/z calcd for C32
99.21259 [M + H] .
H
27
O
2
N
4
: 499.21285; found: 1199, 1158; HRMS: m/z calcd for C32
H
29
O
2
N
6
: 529.23465; found:
+
+
529.23418 [M + H] .
2.2.3 Naphthalene-2,6-diylbis((4-phenoxyphenyl)methanone)
hydrazone (2c). A suspension of EKNKE 1c (0.28 g, 0.53 mmol)
in ethanol (7 ml) was treated with hydrazine monohydrate
2.3 Synthesis of bis(aryldiazomethane)s
(0.52 ml, 10.6 mmol). A few drops of acetic acid (about 0.2 ml)
2.3.1 1,3-Bis(diazo(4-phenoxyphenyl)methyl)benzene (3a).
were added as catalyst. The resulting mixture was heated to A mixture of manganese dioxide (0.22 g, 2.48 mmol), sodium
a gentle reux for 40 h. Aer cooling, the mixture was ltered sulfate (0.19 g, 1.34 mmol), and potassium hydroxide (0.06 g,
and the precipitate was dried in an oven. The crude product 2c 1.35 mmol) was added to a solution of 2a (0.23 g, 0.46 mmol) in
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111277

View Article Online
RSC Advances
Paper
ꢀ
dichloromethane (15 ml). The mixture was vigorously stirred for decomposition. Mp: 110 C (decomposed); d
H
(500.3 MHz,
2
hours in the dark, and then ltered through a pad of Celite™. CDCl ): 3.53 (s, 4H), 6.62 (m, 4H), 6.83 (m, 4H), 6.91 (m, 4H),
3
The ltrate was concentrated under vacuum to yield 3a (90%) as 7.11–7.18 (m, 8H); dC (125.8 MHz, CDCl ): 61.8, 116.3, 118.1,
3
a purple solid and then stored at sub-ambient temperature to 121.1, 122.3, 125.1, 126.5, 127.3, 142.9, 148.4, 157.5; IR n
max
ꢀ
ꢁ1
avoid decomposition. Mp: 70–74 C; d
H
(400.3 MHz, CDCl
): 62.0, 119.0, 119.7,
20.2, 121.5, 123.5, 123.5, 127.3, 129.9, 131.2, 155.7, 157.0; IR
3
): (cm ): 3426, 3376, 3295, 3196, 3036, 2023, 1496, 1239.
C 3
6.55–7.58 (m, 22H); d (100.7 MHz, CDCl
1
ꢁ
1
2.4 Synthesis of bis(arylester)s
nmax (cm ): 3039, 2031, 1588, 1503, 1486, 1234, 1165.
2.3.2 1,4-Bis(diazo(4-phenoxyphenyl)methyl)benzene (3b).
2.4.1 1,3-Phenylenebis((4-phenoxyphenyl)methylene) diac-
A mixture of manganese dioxide (0.22 g, 2.48 mmol), sodium etate (4a). Acetic acid (2.86 ml, 50.0 mmol) was added to
sulfate (0.19 g, 1.34 mmol), and potassium hydroxide (0.06 g, a solution of 3a (0.25 g, 0.5 mmol) in DCM (10 ml). The mixture
1.35 mmol) was added to a solution of 2b (0.23 g, 0.46 mmol) in was stirred in the dark at room temperature until the color
dichloromethane (120 ml). The mixture was vigorously stirred changed from purple to light yellow (about 20 min). The mixture
for 2 hours in the dark, and then ltered through a pad of was washed with 2 M Na CO aq. solution (60 ml), water (20 ml
2
3
Celite™. The ltrate was concentrated under vacuum to yield ꢂ 3), dried with MgSO and concentrated under reduced pres-
4
3
b (86%) as a purple solid and then stored at sub-ambient sure. The crude product was puried by chromatography on
ꢀ
temperature to avoid decomposition. Mp: 110 C (decom- a silica gel column eluting with petrol ether/ethyl acetate (3/1) to
pose); dH (400.3 MHz, CDCl ): 6.92–7.46 (m, 22H); d (100.7 give the product 4a as a light yellow sticky liquid (71%). dH
3
C
MHz, CDCl ): 62.0, 118.9, 119.7, 123.5, 123.7, 125.3, 126.5, (400.3 MHz, CDCl ): 2.03 (d, 6H), 6.78 (s, 2H), 6.87 (m, 4H), 6.92
3
3
ꢁ1
1
1
27.2, 129.8, 155.6, 157.1; IR nmax (cm ): 3035, 2022, 1588, (m, 4H), 7.03 (t, 2H), 7.15–7.28 (m, 12H); d (100.7 MHz, CDCl ):
C 3
503, 1485, 1239, 1164.
.3.3 2,6-Bis(diazo(4-phenoxyphenyl)methyl)naphthalene 128.9(d), 129.8, 134.7, 140.5, 156.8, 157.2, 170.0; IR nmax (cm ):
3c). A mixture of manganese dioxide (0.22 g, 2.48 mmol), 3063, 3039, 1740, 1590, 1506, 1488, 1370, 1226, 1168, 1023;
sodium sulfate (0.19 g, 1.34 mmol), and potassium hydroxide HRMS: m/z calcd for C36 Na: 581.19346; found: 581.19326
21.3, 76.2, 118.5, 119.2, 123.6, 125.5, 125.6, 126.5, 128.8(d),
ꢁ
1
2
(
30 6
H O
+
(0.06 g, 1.35 mmol) was added to a solution of 2c (0.25 g, 0.46 [M + Na] .
mmol) in dichloromethane (120 ml). The mixture was vigor-
2.4.2 1,4-Phenylenebis((4-phenoxyphenyl)methylene) diac-
ously stirred for 2 hours in the dark, and then ltered through etate (4b). Acetic acid (2.86 ml, 50.0 mmol) was added to
a pad of Celite™. The ltrate was concentrated under vacuum a solution of 3a (0.25 g, 0.5 mmol) in DCM (10 ml). The mixture
to yield 3c (85%) as a purple solid and then stored at sub- was stirred in the dark at room temperature until the color
ꢀ
ambient temperature to avoid decomposition. Mp: 118
decompose); d (500.3 MHz, CDCl
.09 (m, 2H), 7.25–7.33 (m, 10H), 7.54 (d, 2H), 7.66 (d, 2H); d
125.8 MHz, CDCl
C
changed from purple to light yellow (about 20 min). The mixture
(
7
(
H
3
2 3
): 6.97–7.04 (m, 8H), 7.04– was washed with 2 M Na CO aq. solution (60 ml), water (20 ml
C
ꢂ 3), dried with MgSO
4
and concentrated under reduced pres-
3
): 62.5, 119.0, 119.7, 122.1, 123.6, 123.8, sure. The crude product was puried by chromatography on
1
23.8, 126.7, 127.5, 128.2, 129.9, 132.0, 155.9, 157.0; IR n
a silica gel column eluting with petrol ether/ethyl acetate (3/1) to
give the product 4b as a light yellow sticky liquid (67%). dH
max
ꢁ1
(cm ): 3057, 3037, 2020, 1643, 1589, 1484, 1249, 1161.
0
2
.3.4 4,4 -(((1,3-Phenylenebis(diazomethylene))bis(4,1- (400.3 MHz, CDCl ): 2.07 (d, 6H), 6.77 (s, 2H), 6.87 (m, 4H), 6.93
3
phenylene))bis(oxy))dianiline (3d). A mixture of manganese (m, 4H), 7.03 (t, 2H), 7.17–7.29 (m, 12H); d (100.7 MHz, CDCl ):
C
3
dioxide (0.22 g, 2.48 mmol), sodium sulfate (0.19 g, 1.34 mmol), 21.3, 76.2, 118.5, 119.2, 123.6, 127.1, 127.2, 128.7, 129.8, 134.6,
ꢁ1
and potassium hydroxide (0.06 g, 1.35 mmol) was added to 139.9, 156.8, 157.2, 170.0; IR nmax (cm ): 3061, 3039, 1739,
a solution of 2d (0.24 g, 0.46 mmol) in dichloromethane (15 ml). 1590, 1506, 1488, 1370, 1227, 1167, 1019; HRMS: m/z calcd for
+
The mixture was vigorously stirred for 5 hours in the dark, and
then ltered through a pad of Celite™. The ltrate was
concentrated under vacuum to yield 3d (89%) as a purple solid
C
36
H
30
O
6
Na: 581.19346; found: 581.19376 [M + Na] .
2.4.3 Naphthalene-2,6-diylbis((4-phenoxyphenyl)methylene)
diacetate (4c). Acetic acid (2.86 ml, 50.0 mmol) was added to
and then stored at sub-ambient temperature to avoid decom- a solution of 3a (0.27 g, 0.5 mmol) in DCM (10 ml). The mixture
ꢀ
position. Mp: 115 C (decomposed); d
H
(500.3 MHz, CDCl
(125.8 MHz, CDCl ): 61.8, 116.3, changed from purple to light yellow (about 20 min). The mixture
18.1, 119.9, 121.1, 121.1, 127.4, 129.8, 131.3, 142.9, 148.4, was washed with 2 M Na CO aq. solution (60 ml), water (20 ml
3
): 3.52 was stirred in the dark at room temperature until the color
(
s, 4H), 6.50–7.34 (m, 20H); d
C
3
1
1
2
3
ꢁ
1
57.5; IR nmax (cm ): 3446, 3366, 3038, 2031, 1590, 1495, 1228. ꢂ 3), dried with MgSO
4
and concentrated under reduced pres-
0
2
.3.5 4,4 -(((1,4-Phenylenebis(diazomethylene))bis(4,1- sure. The crude product was puried by chromatography on
phenylene))bis(oxy))dianiline (3e). A mixture of manganese a silica gel column eluting with petrol ether/ethyl acetate (3/1) to
dioxide (0.22 g, 2.48 mmol), sodium sulfate (0.19 g, 1.34 mmol), give the product 4c as a light yellow sticky liquid (70%). dH
and potassium hydroxide (0.06 g, 1.35 mmol) was added to (400.3 MHz, CDCl ): 2.08 (d, 6H), 6.76–6.93 (m, 10H), 6.98 (t,
3
a solution of 2e (0.24 g, 0.46 mmol) in dichloromethane (150 2H), 7.21 (t, 8H), 7.71 (d, 4H); d (100.7 MHz, CDCl ): 21.4, 76.5,
C
3
ml). The mixture was vigorously stirred for 5 hours in the dark, 118.6, 119.2, 123.6, 125.4, 125.6, 128.7, 128.9, 129.9, 132.7,
ꢁ1
and then ltered through a pad of Celite™. The ltrate was 134.8, 138.1, 156.8, 157.2, 170.1; IR nmax (cm ): 3039, 1738,
concentrated under vacuum to yield 3e (92%) as a purple solid 1589, 1505, 1487, 1369, 1223, 1166, 1021; HRMS: m/z calcd for
+
and then stored at sub-ambient temperature to avoid
C
40
H
32
O
6
Na: 631.20911; found: 631.20890 [M + Na] .
111278 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
.4.4 1,3-Phenylenebis((4-(4-aminophenoxy)phenyl)methy-
RSC Advances
2
2.6.3 Fast Red dyed polymers (11a–c, 12a–c). Polymers 5a–c
lene) diacetate (4d). Acetic acid (2.86 ml, 50.0 mmol) was added and 6a–c were dyed by immersing the functionalized polymers
to a solution of 3d (0.27 g, 0.5 mmol) in DCM (10 ml). The in a 0.03 M solution of Fast Red RC salt in acetone/water (1 : 4)
mixture was stirred in the dark at room temperature until the for 18 h at room temperature. The polymers were then collected
color changed from purple to light yellow (about 20 min). The by ltration and washed with acetone to furnish the corre-
mixture was washed with 2 M Na CO aq. solution (60 ml), water sponding polymers 11a–c and 12a–c
2
3
(
20 ml ꢂ 3), dried with MgSO and concentrated under reduced
2.6.4 Fluorodiazonium salt dyed polymers (13a(f–g), 14a(f–
4
pressure. The crude product was puried by chromatography g)). To a solution of uorodiazonium salt 15f–g in EtOH (5 ml)
on a silica gel column eluting with DCM/acetone (10/1) to give was added the polymer 5a or 6a, and then the mixture was
ꢀ
ꢀ
the product 4d as a light yellow solid (68%). Mp: 76–80 C; d
500.3 MHz, CDCl ): 2.03 (d, 6H), 3.51 (s, 4H), 6.51–6.58 (m, 4H), washed with acetone and dried to yield the C
.70–6.82 (m, 10H), 7.08–7.18 (m, 6H), 7.18–7.25 (m, 2H); d polystyrene 13af, C 13-functionalized polyacrylate 13ag, C10
125.9 MHz, CDCl ): 21.3, 76.3, 116.3, 117.0, 121.3, 125.4(d), functionalized polystyrene 14af, C10 21-functionalized poly-
26.4(d), 128.8, 133.5, 140.6, 143.1, 148.1, 158.9, 170.1; IR n acrylate 14ag.
H
stored in the fridge (0–5 C) for 18 h. Aer that, the polymer was
(
6
(
1
3
6
F13-functionalized
C
6
F
21
F -
3
F
max
ꢁ1
(
cm ): 3453, 3368, 3040, 2980, 1733, 1611, 1498, 1370, 1223,
1
167, 1022; HRMS: m/z calcd for C H O N Na: 611.21526;
3
6
32 6 2
+
found: 611.21453 [M + Na] .
.4.5 1,4-Phenylenebis((4-(4-aminophenoxy)phenyl)methy-
lene) diacetate (4e). Acetic acid (2.86 ml, 50.0 mmol) was added
2.7 Synthesis of bis(arylketone)s
2
2.7.1 2,2,2-Triuoro-N-(4-phenoxyphenyl)acetamide (16).
to a solution of 3e (0.27 g, 0.5 mmol) in DCM (10 ml). The 4-Phenoxyaniline (3.0 g, 16.2 mmol) and pyridine (3.93 ml, 48.6
mixture was stirred in the dark at room temperature until the mmol) were dissolved in DCM (50 ml) with magnetic stirring.
ꢀ
color changed from purple to light yellow (about 20 min). The Aer cooling the solution to 5 C in an ice/water bath, a solution
mixture was washed with 2 M Na CO aq. solution (60 ml), water of triuoroacetic anhydride (3.38 ml, 24.3 mmol) in DCM (15
2
3
(
20 ml ꢂ 3), dried with MgSO and concentrated under reduced ml) was added dropwise. Aer the addition, the solution
4
pressure. The crude product was puried by chromatography continued stirring overnight at room temperature. Aer that,
on a silica gel column eluting with DCM/acetone (10/1) to give the solution was evaporated under vacuum. Acetone (10 ml) was
ꢀ
the product 4e as a light yellow solid (73%). Mp: 100–104 C; d
H
added to dissolve the residue and the solution was poured into
(
500.3 MHz, CDCl
3
): 2.06 (d, 6H), 3.53 (s, 4H), 6.55–6.62 (m, 4H), cold water (300 ml) and stirred for 10 minutes. The mixture was
.70–6.82 (m, 10H), 7.10–7.27 (m, 8H); d (125.9 MHz, CDCl
): ltered under vacuum and the solid was collected and dried in
1.3, 76.2, 116.2, 116.9, 121.3, 127.1(d), 128.6(d), 133.5, 139.9, an oven at 80 C (96%). Mp: 118–120 C; d ):
3
6
2
1
2
C
3
ꢀ
ꢀ
(400.3 MHz, CDCl
43.0, 148.1, 158.8, 170.0; IR nmax (cm ): 3449, 3372, 3038, 6.83–6.95 (m, 4H), 7.02 (t, 1H), 7.24 (t, 2H), 7.40 (d, 2H), 8.27 (s,
927, 1733, 1612, 1498, 1371, 1227, 1168, 1017; HRMS: m/z calcd 1H); d (100.7 MHz, CDCl ): 115.9(q), 119.1, 119.3, 122.6, 123.8,
129.9, 130.1, 155.2(q), 155.6, 156.8; d (376.6 MHz, CDCl ): 75.6;
IR nmax (cm ): 3293, 1704, 1593, 1540, 1488, 1229, 1151; HRMS:
H
ꢁ1
C
3
+
for C36H
32
O
6
N
2
Na: 611.21526; found: 611.21518 [M + Na] .
F
3
ꢁ
1
m/z calcd for C14
H
11
O
2
NF
3
: 282.07364; found: 282.07376 [M +
2
.5 Modication of polymers
To a solution of diazomethane 3a–c (0.1 g) in dichloromethane
10 ml) was added the required polymer (0.4 g), and then the
+
H] .
0
2
.7.2 N,N -(((Isophthaloylbis(4,1-phenylene))bis(oxy)bis(4,1-
(
phenylene))bis(2,2,2-triuoroacetamide) (1d). Aluminum chlo-
ride (0.49 g, 3.70 mmol) was added to DCM (20 ml) and the
solution was cooled to 5 C with an ice/water bath. To that
mixture was added 16 (0.42 g, 1.48 mmol) and isophthaloyl
chloride (0.15 g, 0.74 mmol) in order. The mixture was stirred at
room temperature for 2 hours. The reaction mixture was evap-
orated under vacuum before acetone (10 ml) was added. The
mixture was concentrated under vacuum. The polymer was
collected and heated in an open ask to 120 C for 30 min. The
resulting solid was washed with dichloromethane for three
times and the solid was dried to yield the functionalized poly-
styrenes 5a–c and polyacrylates 6a–c.
ꢀ
ꢀ
2.6 Preparation of dyed polymers
mixture in acetone was poured into cold water to yield a light
ꢀ
2
.6.1 Fast Black dyed polymers (7a–c, 8a–c). Polymers 5a–c pink precipitate, which was ltered and dried in an oven (80 C).
and 6a–c were dyed by immersing the functionalized polymers Aer that, the solid was dispersed in DCM (10 ml) and ltered
in a 0.01 M solution of Fast Black K salt in acetone/water (1 : 1) again to get rid of unreacted starting material 16. The mixture
for 18 h at room temperature. The polymers were then collected was ltered and the precipitate was dried under room temper-
ꢀ
by ltration and washed with acetone to furnish the corre- ature to obtain a light pink solid (89%). Mp: 236–238 C; d
H
sponding polymers 7a–c and 8a–c.
.6.2 Fast Dark Blue dyed polymers (9a–c, 10a–c). Polymers 7.85 (d, 4H), 7.91 (d, 4H), 8.05 (d, 2H), 8.11 (t, 1H), 10.4 (s, 2H);
a–c and 6a–c were dyed by immersing the functionalized (125.8 MHz, acetone-d6): 116.1(q), 117.2, 120.7, 122.8, 128.8,
polymers in a 0.01 M solution of Fast Dark Blue R salt in 130.4, 131.8, 132.4, 132.8, 133.2, 138.1, 152.9, 154.7(q), 161.7,
(500.3 MHz, acetone-d6): 7.14 (d, 4H), 7.23 (d, 4H), 7.77 (t, 1H),
2
5
d
C
ꢁ
1
acetone/water (1 : 1) for 18 h at room temperature. The poly- 193.7; d (376.6 MHz, acetone-d6): 76.1; IR nmax (cm ): 3285,
F
mers were then collected by ltration and washed with acetone 1706, 1650, 1598, 1542, 1504, 1238, 1179, 1152; HRMS: m/z calcd
ꢁ
to furnish the corresponding polymers 9a–c and 10a–c.
for C36H
21
O
6
N
2
F
6
: 691.13093; found: 691.12988 [M ꢁ H] .
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111279

View Article Online
RSC Advances
Paper
0
ꢀ
2
.7.3 N,N -(((Terephthaloylbis(4,1-phenylene))bis(oxy))bis(4,1- solid (70%). Mp: 68–70 C; d
H
(500.3 MHz, acetone-d6): 2.43 (m,
phenylene))bis(2,2,2-triuoroacetamide) (1e). Aluminum chlo- 2H), 3.43 (q, 2H), 5.10 (t, 1H), 6.57 (d, 2H), 7.36 (d, 2H), 9.82 (s,
ride (0.49 g, 3.70 mmol) was added to DCM (20 ml) and the 1H); d
solution was cooled to 5 C with an ice/water bath. To that 122.5, 126.3, 146.1, 154.2(q); d
(125.8 MHz, acetone-d6): 30.1(t), 35.4(t), 112.4, 116.3(q),
C
ꢀ
(470.4 MHz, acetone-d6): ꢁ70.9,
F
ꢁ1
mixture was added 16 (0.42 g, 1.48 mmol) and terephthaloyl ꢁ76.6, ꢁ109.2, ꢁ117.3, ꢁ118.3, ꢁ118.9, ꢁ121.6; IR nmax (cm ):
chloride (0.15 g, 0.74 mmol) in order. The mixture was stirred at 3426, 3377, 1700, 1617, 1524, 1244, 1231, 1144; HRMS: m/z calcd
+
room temperature for 2 hours. The reaction mixture was evap- for C16
H
11ON
2
F
16: 551.06079; found: 551.06077 [M + H] .
orated under vacuum before acetone (10 ml) was added. The
2.8.4 4-1H,1H,2H,2H-Peruorodocecylaminophenyl
tri-
mixture in acetone was poured into cold water to yield a light uoroacetamide (19g). 18 (0.20 g, 0.98 mmol) and 1H,1H,2H,2H-
ꢀ
pink precipitate, which was ltered and dried in an oven (80 C). peruorododecyl iodide (0.22 g, 0.33 mmol) were mixed
ꢀ
Aer that, the solid was dispersed in acetone (10 ml) and together and heated to 140 C for 18 h. The crude product was

ltered again to get rid of unreacted starting material 16. The puried by chromatography on a silica gel column eluting with
mixture was ltered and the precipitate was dried under room petrol ether/ethyl acetate (8 : 1) to give the product 11b as a light
ꢀ
ꢀ
temperature to obtain a light pink solid (86%). Mp: 324–327 C; yellow solid (49%). Mp: 120–122 C; d
H
(400.3 MHz, acetone-d6):
d (400.3 MHz, CDCl /TFA(1 : 1)): 7.18 (d, 4H), 7.26 (d, 4H), 7.67 2.44 (m, 2H), 3.43 (q, 2H), 5.13 (t, 1H), 6.58 (d, 2H), 7.37 (d, 2H),
H
3
(
d, 4H), 7.96 (m, 2H), 7.98 (m, 6H),8.70 (s, 2H); d (100.6 MHz, 9.85 (s, 1H); d
C
(125.8 MHz, acetone-d6): 30.1(t), 35.4(t), 112.4,
C
CDCl
3
/TFA(1 : 1)): 114.2(q), 117.5, 121.3, 123.7, 130.0, 130.1, 116.4(q), 122.5, 126.3, 146.1, 154.2(q); d (376.6 MHz, acetone-
F
1
30.6, 133.9, 140.6, 153.9, 162.2(q), 163.4, 199.9; d
F
(376.6 MHz, d6): ꢁ76.1, ꢁ81.7, ꢁ114.5, ꢁ122.3, ꢁ122.4, ꢁ123.3, ꢁ124.1,
ꢁ
1
ꢁ1
CDCl
1
C
3
/TFA(1 : 1)): 76.3; IR nmax (cm ): 3280, 2980, 1706, 1647, ꢁ126.8; IR nmax (cm ): 3311, 1696, 1551, 1523, 1839, 1148;
598, 1544, 1507, 1240, 1179, 1151; HRMS: m/z calcd for HRMS: m/z calcd for
C
H
11ON
F
:
751.04827; found:
20
2
24
ꢁ
+
H
21
O
6
N
2
F
6
: 691.13093; found: 691.13074 [M ꢁ H] .
751.00783 [M + H] .
.8.5 4-1H,1H,2H,2H-Peruorooctylamino aniline (20f).
9f (1.87 g, 3.41 mmol) and K CO (4.71 g, 34.1 mmol) were
added to a 100 ml ask with MeOH (50 ml). The mixture was
.8.1 4-Nitrophenyl triuoroacetamide (17). To a solution heated to reux for 18 h, and then MeOH was evaporated off.
36
2
1
2
3
2.8 Synthesis of uoro-diazonium salts
2
of 4-nitroaniline (3.00 g, 21.6 mmol) and pyridine (5.24 ml, 64.8 Water (50 ml) was added to the residue and ethyl acetate was
mmol) in dichloromethane (100 ml) was added a triuoroacetic used to extract (50 ml ꢂ 2). The organic layer was washed with
anhydride (4.51 ml, 32.4 mmol) solution in dichloromethane water (50 ml ꢂ 3), dried with MgSO
, and concentrated to
4
(
15 ml) drop by drop. Aer that, the mixture was stirred for 18 h obtain a brown solid. The crude product was puried by chro-
before the solvent was evaporated out. Acetone (50 ml) was matography on a silica gel column eluting with petrol ether/
added to dissolve the residue and the solution was poured to an ethyl acetate (2 : 1) to give the product 20f as a brown solid
ꢀ
ice/water mixture (400 ml) to crystallize and lter. The solid was (86%). Mp: 72–74 C; d
H
(400.3 MHz, CDCl
3
): 2.25 (m, 2H), 3.27
(100.7 MHz, CDCl ): 30.7(t),
(376.6 MHz, CDCl
): ꢁ81.0,
ꢀ
collected and dried in an oven (80 C, 4 h) to acquire a yellow (s, 3H), 3.35 (t, 2H), 6.48 (m, 4H); d
C
3
ꢀ
solid (95%). Mp: 151–153 C; d
H
(400.3 MHz, DMSO-d6): 7.93 (d, 37.0, 114.9, 116.9, 138.6, 139.8; d
(125.8 MHz, DMSO-d6): ꢁ114.0, ꢁ122.0, ꢁ123.0, ꢁ123.7, ꢁ126.3; IR nmax (cm ): 3415,
15.9(q), 121.3, 125.2, 142.9, 144.4, 155.4(q); d
(376.6 MHz, 3337, 1608, 1517, 1364, 1324, 1258, 1239, 1140, 1111; HRMS: m/z
F
3
ꢁ
1
2
1
H), 8.26 (d, 2H), 11.8 (s, 1H); d
C
F
ꢁ
1
+
DMSO-d6): ꢁ74.1; IR nmax (cm ): 3325, 3116, 1742, 1503, 1339, calcd for C14
159, 1139, 1111; HRMS: m/z calcd for C H O N F : 233.07195; 2.8.6 4-1H,1H,2H,2H-Peruorododecylamino aniline (20g).
19g (0.66 g, 0.87 mmol) and K CO (1.21 g, 8.70 mmol) were
.8.2 4-Aminophenyl triuoroacetamide (18). 17 (1.52 g, added to a 100 ml ask with MeOH (50 ml). The mixture was
.5 mmol) and iron powder (3.63 g, 65.0 mmol) were added to heated to reux for 18 h, and then MeOH was evaporated off.
a mixed solvent of EtOH/H
O (25 ml/5 ml). To that was added 2 Water (30 ml) was added to the residue and ethyl acetate was
drops of concentrated HCl aq. solution. The mixture was heated used to extract (30 ml ꢂ 2). The organic layer was washed with
to reux for 3 h, and then ltered with a pad of Celite™. The water (30 ml ꢂ 3), dried with MgSO , and concentrated to
ltrate was evaporated out to obtain a grey solid product 18 obtain a brown solid. The crude product was puried by chro-
12 2
H N F13: 455.07874; found: 455.07790 [M + H] .
1
8
4 3 2 3
ꢁ
found: 233.01758 [M ꢁ H] .
2
3
2
6
2
4

ꢀ
92%). Mp: 120–124 C; d (400.3 MHz, DMSO-d6): 5.16 (s, 2H), matography on a silica gel column eluting with petrol ether/
H
(
6
1
.59 (s, 2H), 7.31 (s, 2H), 10.9 (s, 1H); d (125.8 MHz, DMSO-d6): ethyl acetate (2 : 1) to give the product 20g as a yellow solid
C
ꢀ
14.1, 116.6(q), 123.1, 125.3, 147.2, 154.2(q); d
F
(376.6 MHz, (67%). Mp: 131–133 C; d
H
(400.3 MHz, acetone-d6): 2.36 (m,
(100.6
MHz, acetone-d6): 30.3(t), 36.6, 114.5, 115.9, 139.6, 140.0; d
(376.6 MHz, acetone-d6): ꢁ81.7, ꢁ114.4, ꢁ122.3, ꢁ122.4,
ꢁ
1
DMSO-d6): ꢁ73.8; IR nmax (cm ): 2406, 3335, 3030, 1712, 1515, 2H), 3.30 (t, 2H), 3.86 (s, 2H), 4.18 (t, 1H), 6.40 (m, 4H); d
C
1
2
200, 1181, 1150, 1130; HRMS: m/z calcd for C
8
H
8
ON
2
F
3
:
F
+
05.05832; found: 205.05833 [M + H] .
ꢁ
1
2.8.3 4-1H,1H,2H,2H-Peruorooctylaminophenyl
tri- ꢁ123.3, ꢁ124.1, ꢁ126.8; IR nmax (cm ): 3413, 3336, 1610, 1518,
21: 655.06597;

uoroacetamide (19f). 18 (0.30 g, 1.47 mmol) and 1H,1H,2H,2H- 1201, 1147, 1106; HRMS: m/z calcd for C18H N F
12 2
+
peruorooctyl iodide (0.12 ml, 0.49 mmol) were mixed together found: 655.06453 [M + H] .
and heated to 140 C for 1 h. The crude product was puried by
ꢀ
2.8.7 4-1H,1H,2H,2H-Peruorooctylamino diazonium salt
chromatography on a silica gel column eluting with petrol (15f). 20f (0.2 g, 0.44 mmol), isoamyl nitrite (0.059 ml, 0.44
ether/ethyl acetate (8 : 1) to give the product 19f as a light yellow mmol), tetrauoroboric acid (0.16 ml, 0.88 mmol), and EtOH
111280 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
ꢀ
10 ml) were mixed together at 0 C for 1 h. The mixture was
(

ltered and DCM (50 ml) was added to the ltrate to precipitate.
The solid was ltered and dried under r.t. for a few minutes to
ꢀ
obtain a green solid (82%). Mp: 138–140 C (decomposed); d
H
(500.3 MHz, acetone-d6): 2.68 (m, 2H), 4.61 (t, 2H), 8.43 (d, 2H),
8
1
.98 (d, 2H); d
19.3, 135.3, 150.9; d
122.5, ꢁ123.5, ꢁ124.0, ꢁ126.8, ꢁ151.0; IR nmax (cm ): 3118,
276, 1589, 1524, 1198, 1146, 1064, 1032.
.8.8 4-1H,1H,2H,2H-Peruorododecylamino diazonium
C
(125.8 MHz, acetone-d6): 27.1(t), 34.1(t), 110.6,
F
(376.6 MHz, acetone-d6): ꢁ81.7, ꢁ114.9,
ꢁ
1
ꢁ
2
2
salt (15g). 20g (0.2 g, 0.31 mmol), isoamyl nitrite (0.041 ml, 0.31
mmol), tetrauoroboric acid (0.11 ml, 0.62 mmol), and EtOH
ꢀ
(
10 ml) were mixed together at 0 C for 1 h. The presence of the
24
desired diazonium salt was conrmed using the H-acid test.
A
sample of the diazonium salt solution 15g (1 ml) was adjusted to
pH 4 using sodium acetate and then H-acid (4-amino-5-hydroxy-
2,7-naphthalene disulfonic acid) was added (10 mg). The
mixture was mixed well and le to stand at room temperature
for 15 minutes. The formation of a dark purple color indicated
the generation of diazonium salt.
3. Results and discussion
3.1 Synthesis and characterization of bis(aryldiazomethane)s
As shown in Scheme 2, bis(arylketone)s 1a–e were treated with
hydrazine monohydrate to generate bis(hydrazone)s 2a–e,
which were then oxidized by manganese dioxide to obtain
bis(aryldiazomethane)s 3a–e. The starting materials 1a–c were
commercial reagents, while compounds 1d–e were synthe-
sized. Overall, ve new bis(aryldiazomethane)s were designed
both to test the synthetic approach as well as to study the
difference of polymer modications. As for the synthesis of
1
d–e (Scheme 3), 4-phenoxyaniline was treated with triuoro-
acetic anhydride to give 16, followed by the Friedel–Cras
reaction to generate bis(arylketone)s 1d–e with relatively high
2
7
yield. It is worth noting that bis(aryldiazomethane)s 3d–e
contain unprotected amino groups, but they are very stable in
the oxidation step with manganese dioxide as oxidant. These
oxidation conditions are very mild, allowing selective oxida-
2
8–30
tion of the hydrazone to the diazo compound,
which leaves
Scheme 2
free amine undamaged. The greater stability of these systems
compared to the diazo compound derived from Michler's
2
2
ketone is noteworthy.
In our former work,
modication using bis(arylcarbene)s and their subsequent
the two-step synthesis via hydra- dyeing by diazonium salt coupling. This is a convenient and
19–26
33
zones was reported to be a highly effective approach to obtain efficient method for the introduction of diverse chemical
aryldiazomethanes. However, it was of interest to examine the functionality onto a substrate (Scheme 4). Furthermore, poly-
reaction of bis(aryldiazomethane)s as compared to mono(- styrene beads and polyacrylate beads were used as templates,
aryldiazomethane)s, and for that purpose, acetic acid was used since we have already shown that this approach is equally
19
to react with bis(aryldiazomethane), a known very fast reaction applicable to other substrates. Firstly, polystyrene beads or
3
1,32
used to generate esters.
From the IR spectra, NMR spectra, polyacrylate beads were mixed with bis(aryldiazomethane)s and
ꢀ
and MS data, the structures of bis(arylester)s products 4a–e were heated at 120 C, to form modied polystyrenes 5a–e and
conrmed, and no mono(arylester)s were formed.
modied polyacrylates 6a–e. In this step, carbenes are gener-
ated from diaryldiazomethanes by heating, followed by their
insertion reaction with C–H bond (on the surface of XAD4 and
MAC-3) or O–H bond (on the surface of MAC-3), which leads to
the modied polymer beads. For modied polymer beads 5a–c
3.2 Preparation of modied or dyed polymers
In order to allow rapid access to functionalized polymers, we
adapted our previously published approach for surface
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111281

View Article Online
RSC Advances
Paper
Scheme 3
Scheme 4
or 6a–c, which only contain phenoxy groups with the elements Fast Black K salt, Fast Dark Blue R salt, and Fast Red RC salt
of carbon, hydrogen, and oxygen, the chemical structure is very were used to dye those polymers, giving the corresponding
similar to starting polymer beads (XAD4 or MAC-3), and hence derivatives: Fast Black dyed polystyrenes 7a–c, Fast Black dyed
very difficult to characterize. Therefore, commercially available polyacrylates 8a–c, Fast Dark Blue dyed polystyrenes 9a–c, Fast
111282 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
Dark Blue dyed polyacrylates 10a–c, Fast Red dyed polystyrenes 3.3 Surface properties
11a–c, Fast Red dyed polyacrylates 12a–c. The structure of Fast
3.3.1 Colour. It is interesting that modied polymer beads
Black K salt, Fast Dark Blue R salt, and Fast Red RC salt are
depicted in Scheme 4. All of those dyes are aromatic diazonium
salts, which can easily react with phenoxyl groups by azo
coupling reaction. In this way, the elements of nitrogen or
chlorine were introduced to the polymer beads 5a–c or 6a–c,
and which are easily detected by XPS or Elemental Analysis. On
the other hand, for modied polystyrene beads 5d–e and poly-
acrylate beads 6d–e that already contain amino groups, there is
no need for this dyeing step. In addition, two uoro-diazonium
salts 15(f–g) were synthesized, and then used to dye polymer
beads 5a and 6a, to generate uoro-polystyrenes 13a(f–g) and
5
and 6 show light yellow colour, indicative of the introduction
of the weak aromatic chromophore of the carbene unit. Aer
the reaction with commercial dyes by azo coupling in the
second step, even more intensely colored polymer beads were
obtained, which enabled access to a library of coloured poly-
mers (Table 1).
3.3.2 XPS analysis. As mentioned above, there is no distinct
variation of element in polymers 5a–c and 6a–c before and aer
modication with bis(arylcarbene)s so that it is very difficult to
test whether the modication protocol is successful or not.
Therefore, three commercial diazonium salts, which contain
nitrogen and chlorine, and two uorine containing diazonium
salts, were used to dye the modied polymers in a second step.
The presence of nitrogen (Fig. 1(1)–(3)), chlorine (Fig. 1(5)),

uoro-polyacrylates 14a(f–g) (Scheme 4). Thus, chemical func-
tionality can be readily introduced to polymers.
The synthetic route for the preparation of the uoro-
diazonium salt is shown in Scheme 5. Firstly, 4-nitroaniline
was converted into 4-triuoroacetylamino aniline 18 by a two-
step reaction. This step is required because the strongly
electron-withdrawing nitro group makes the amino group very
inert, which does not react with peruoroalkyl iodide. Two

uorine (Fig. 1(6)), and their loading density on the surface were
conrmed by XPS analysis (Table 2). Similarly, the presence of
nitrogen in modied polymers 5d–e and 6d–e was directly
detected by XPS (Fig. 1(4)). The binding energy was calibrated by
the HOPG carbon before analysis. All of the detailed data were
calculated using the CasaXPS soware and the reference library
of ALSCOF, and the results were shown in Table 2.
kinds of peruoroalkyl iodide with different numbers of CF
2
34,35
unit were then reacted with 18 to generate 19(f–g),
and
subsequent cleavage of triuoroacetyl group gave 20(f–g).
Finally, uoroamines 20(f–g) were treated with isoamyl nitrite
to give uoro-diazonium salts 15(f–g). The uorodiazonium
salts could be isolated and their chemical structures could be
easily veried by IR and NMR analysis, but were best stored
below zero degrees Celsius. Application of the H-acid (4-amino-
From Table 2, the observed N/C ratio conrms the insertion
reaction of bis(arylcarbene)s into the polymer, although the
detected value is generally smaller than the expected value.
Reasons for this have been previously discussed, but the N/Cl
and N/F ratios were in much better accordance with the ex-
pected values. It was observed that the modication effect
2
seems better when the substituent in R structure is at the meta-
position (5a, 5d, 6a, 6d). Moreover, different states of nitrogen
in the dyed polymers were detected (Fig. 1) with N 1 s signals at
22
5-hydroxy-2,7-naphthalene disulfonic acid) test also conrmed
success of the diazo reaction (formation of intense
36
colouration).
Scheme 5
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111283

View Article Online
RSC Advances
Paper
Table 1 Library of modified and dyed polymer beads
XAD4 Structure
Color
MAC-3 Structure
Color
5
a
R
R
1
¼ H, R
2
¼ 1,3-C
¼ 1,4-C
6
H
4
6a
6b
R
1
¼ H, R
¼ H, R
2
¼ 1,3-C
6
H
H
4
5
b
1
¼ H, R
2
6
H
4
R
1
2
¼ 1,4-C
6
4
5
c
R
1
¼ H, R
2
¼ 1,5-C10
H
6
6c
R
1
¼ H, R
2
¼ 1,5-C10
H
6
5
5
7
d
e
a
R
R
R
1
1
1
¼NH
2
, R
2
¼ 1,3-C
6
H
4
6d
6e
8a
R
R
R
1
1
1
¼NH
¼NH
2
, R
2
¼ 1,3-C
¼ 1,4-C
6
H
4
¼NH
2
, R
2
¼ 1,4-C
6
H
4
2
, R
2
6
H
4
¼ H, R
¼ H, R
¼ H, R
¼ H, R
¼ H, R
2
2
2
2
2
¼ 1,3-C
¼ 1,4-C
6
H
4
¼ H, R
¼ H, R
¼ H, R
¼ H, R
¼ H, R
2
2
2
2
2
¼ 1,3-C
6
H
H
4
7
7
9
9
b
c
R
R
R
R
1
1
1
1
6
H
4
8b
R
1
R
1
R
1
R
1
¼ 1,4-C
6
4
¼ 1,5-C10
H
6
8c
¼ 1,5-C10
H
6
a
b
¼ 1,3-C
¼ 1,4-C
6
H
4
10a
10b
¼ 1,3-C
6 4
H
6
H
4
¼ 1,4-C
6 4
H
111284 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
Table 1 (Contd.)
XAD4 Structure
Color
MAC-3 Structure
Color
9
c
R
R
1
¼ H, R
2
¼ 1,5-C10
H
6
10c
12a
R
1
¼ H, R
¼ H, R
2
¼ 1,5-C10
H
6
1
1a
1
¼ H, R
2
¼ 1,3-C
¼ 1,4-C
6
H
4
R
1
2
¼ 1,3-C
6
H
4
1
1
1
1b
1c
R
R
R
1
1
1
¼ H, R
¼ H, R
¼ H, R
2
2
2
6
H
4
12b
12c
R
1
R
1
R
1
¼ H, R
¼ H, R
¼ H, R
2
2
2
¼ 1,4-C
6
H
4
¼ 1,5-C10
H
6
¼ 1,5-C10
H
6
3af
¼ 1,3-C
¼ 1,3-C
6
H
4
, R
f
¼ C
6
F
13
14af
¼ 1,3-C
6
H
4
, R
f
6 13
¼ C F
1
3ag
R
1
¼ H, R
2
6
H
4
, R
f
¼ C10
F
21
14ag
R
1
¼ H, R
2
¼ 1,3-C
6
H
4
, R
f
¼ C10F
21
binding energies of 400 eV (N]N) and 406 eV (NO
2
), respec- because their surface areas were almost half compared to starting
tively. The following is the comparison of dyed polymers (8a, polystyrene beads (XAD4). However, for the samples 5b, 5c, and
0a, 12a) by different diazonium salts, which were obtained 5e, their surface areas were nearly unchanged and their modi-
37
1
from polymer 6a. There is a nitro group in Fast Black or Fast cation loading was not so good, and this was in accordance with
Blue, so polymer 8a or 10a shows a peak at 406 eV in Fig. 1(1) or the XPS data in Table 2. Aer repeating this experiment several
Fig. 1(2). The area of that peak is about one quarter to the area of times, it was concluded that the poor solubility of 3b, 3c, and 3e
the peak at 400 eV, which belongs to the N]N group. That is in any solvent was responsible, since it did not allow intimate
greatly in accordance with the quantitative ratio of two different mixing with the polymers in DCM solution in the rst step.
types of nitrogen although the signal to noise ratio of those
Furthermore, BJH pore size distribution of samples 5a–e are
peaks is very low. However, for the Fast Red system, there is no shown in Fig. 2. All the samples have very similar pore size
˚
nitro group so that only one peak at 400 eV is found in polymer distribution with peaks at about 200 A, because the pore size in
1
2a (Fig. 1(3)). The same situation occurs in polymer 6d, which polystyrene samples is much larger than the reacting bis(ar-
only has amino groups modied on its surface so that one peak yldiazomethane) molecules. That clear feature shows that the
at 400 eV is found by XPS. modication by bis(arylcarbene) insertion reaction greatly
.3.3 Surface area and pore size distribution. The results of changes the surface property of materials without blocking the
3
BET surface area are shown in Table 3. It can be found that the mesopores, which has potential application in the research area
modication effect of 5a and 5d is much better than others of catalysts.
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111285

View Article Online
RSC Advances
Paper
Fig. 1 Typical XPS peaks from modified or dyed polymers: (1) 8a for N; (2) 10a for N; (3) 12a for N; (4) 6d for N; (5) 8a for Cl; (6) 14ag for F.
Table 2 XPS data of modified and dyed polymers
a
b
a
b
a
b
Sample Substrate Formula
N/C expected
XPS N/C found
N/Cl expected
XPS N/Cl found
N/F expected
XPS N/F found
c
c
d
d
7
8
9
1
1
1
1
1
1
1
1
1
1
1
5
6
5
6
a
a
a
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
XAD-4
MAC-3
C
60
C
60
C
60
C
60
C
46
C
46
C
46
C
46
C
50
C
50
C
56
C
56
C
64
C
64
C
32
C
32
C
32
C
32
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
48
N
N
10
10
O
O
10
0.167
0.167
10 0.167
0.019
0.038
0.015
0.035
0.013
0.025
0.010
0.021
0.008
0.019
0.010
0.030
0.019
0.035
0.019
0.060
0.016
0.056
—
—
—
—
c
c
d
d
48
10
—
—
—
—
d
d
44Cl
44Cl
36Cl
36Cl
36Cl
36Cl
38Cl
38Cl
4
4
2
2
2
2
2
2
N
N
N
N
N
N
N
N
N
N
N
N
10
O
O
O
2.500
2.500
2.000
2.000
2.000
2.000
2.000
2.000
2.652
3.051
1.015
1.760
1.382
2.190
1.125
2.150
—
—
d
d
0a
1a
2a
1b
2b
1c
2c
3af
4af
3ag
4ag
d
10
10 0.167
0.087
0.087
0.087
0.087
0.080
0.080
0.107
0.107
0.093
0.093
0.063
0.063
0.063
0.063
—
—
d
d
4
4
4
4
4
4
6
6
6
6
2
—
—
d
d
O
2
2
2
2
2
2
2
2
2
—
—
d
d
O
O
O
O
O
O
O
O
—
—
d
d
—
—
d
d
—
—
d
d
—
—
c
c
34
34
34
34
28
28
28
28
F
F
F
F
N
N
N
N
26
26
42
42
—
—
0.231
0.231
0.142
0.142
0.231
0.203
0.155
0.142
c
c
—
—
c
c
—
—
c
c
—
—
c
c
d
d
2
2
2
2
O
2
—
—
—
—
c
c
d
d
d
e
e
O
O
O
2
2
2
—
—
—
—
c
c
d
d
—
—
—
—
c
c
d
d
—
—
—
—
a
b
Expected values calculated from molecular formula assuming a surface monolayer of carbene insertion product. Ratio taken from nitrogen and
c
d
carbon counts in a survey spectrum. Samples don't contain nitrogen. Samples don't contain uorine.
Of interest is that because there are two diazo groups in each crosslinking; in fact, for modied polyacrylate, connections
of 3a–e, and both can react with the polymer surface by carbene between polymer beads can be sometimes found, especially for
insertion reaction aer being heated, there is the possibility of the sample 6d (Table 1).
111286 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
Table 3 BET surface area data of modified polystyrene beads
From Fig. 3, seven peaks (1–7) in starting polystyrene beads
(
1
XAD4) were easily assigned. A new peak (i) in the region of
56.4 ppm in polymer 5a appeared when XAD4 was modied
Samples
XAD4
BET surface area
2
ꢁ1
ꢁ1
ꢁ1
ꢁ1
ꢁ1
ꢁ1
with compound 3a, belonging to the carbon of phenolic ether,
which veried the success of the modication. The chemical
shis of phenolic ether in compound 4a are 156.8 ppm and
874.4 ꢃ 2.4 m g
2
5
5
5
5
5
a
b
c
d
e
321.5 ꢃ 0.9 m g
2
871.8 ꢃ 2.5 m g
2
819.4 ꢃ 2.3 m g
1
57.2 ppm, which are very similar to the peak (i) in polymer 5a.
In contrast, two new peaks (ii and iii) in the region of
58.5 ppm and 115.0 ppm in 5d generated aer XAD4 was
2
427.7 ꢃ 1.1 m g
2
886.4 ꢃ 3.0 m g
1
modied with compound 3d. As shown in Fig. 3, the peak (ii) at
58.5 ppm belongs to one of the carbons directly attached to
1
oxygen in the phenolic ether, which is very similar to the
chemical shi of the same carbon in compound 4d (158.9 ppm).
In addition, the peak at 115.0 ppm (iii) belongs to the methine
group that is nearest to the phenolic ether and on the same side
of the amino group (the chemical shi of the same carbon in
compound 4d is 116.3 ppm). Moreover, there is a little differ-
ence between the NMR spectra of 5a and 5d, especially the
chemical shi of the carbon in phenolic ether, which lies in the
inuence of amino groups. All the evidence above proves the
reliability of the modication protocol through bis(arylcarbene)
insertion, and without depolymerisation.
3.4.2 TG/DSC analysis. Samples 5a and 5d were used to run
TG/DSC analysis, as well as starting polystyrene beads (XAD4)
(
Fig. 4). There is only one step in the TG curve and the
Fig. 2 BJH pore size distribution of modified polystyrene beads.
ꢀ
temperature is about 450 C, which belongs to the decomposi-
tion of polystyrene. Corresponding to that, there is a negative
peak at 450 C in the DSC curve, which shows that the decom-
41
ꢀ
3.4 Bulk properties
position reaction is endothermic. It is very clear that there is
nearly no difference between those three samples in the TG/DSC
curve, which means that the bulk property of polystyrene is not
changed aer modication. However, in contrast to the
Bulk properties are critical in the performance of polymers,
since they give the main physical and chemical properties that
38–40
remain during the lifetime of application.
Hence, it is
necessary to show that the change in surface properties is
achieved without compromising the bulk properties, and in
particular that depolymerisation of the substrate does not result
from carbene reaction.
g
decomposition peak, the glass transition peak (T ) of these
highly crosslinked polymers is too weak to be seen, and this is
similar to the blank polystyrene material. This is indicates that
depolymerisation has not occurred, and that structural integrity
of the polymer has been maintained during the surface modi-
3.4.1 Solid state NMR spectra. The polymers used in this
work cannot be dissolved in any deuterated solvent before or
aer modication, which is strongly suggestive that depoly-
merisation during surface modication does not occur. For that

cation process.
.4.3 Elemental analysis. Dyed polymers have the element
3
1
3
of nitrogen, which can be easily detected by Elemental analysis.
As shown in Table 4, the starting polystyrene beads (XAD4) have
no nitrogen, but the dyed polystyrene beads by azo coupling
show clear nitrogen content. That is, nitrogen is introduced
reason, solid state C NMR with CP/MAS is used to conrm
their structure. Polymers 4a and 4d were chosen for the NMR
analysis because their modication loadings were better than
the others, and the spectra were shown in Fig. 3.
Fig. 3 Solid state NMR spectra of before and after modified polystyrenes.
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111287

View Article Online
RSC Advances
Paper
Table 5 Surface loadings data of modified and dyed polystyrene
beads
Value of
n
Loadings
(mmol g
Loadings
(molecule per cm )
ꢁ1
2
Sample
)
ꢁ2
ꢁ3
ꢁ2
ꢁ2
ꢁ2
ꢁ2
ꢁ2
ꢁ1
12
7
7
7
9
1
1
1
5
a
b
c
a
1a
3af
3ag
d
10
10
10
10
4
6
6
2
3.64 ꢂ 10
9.29 ꢂ 10
1.07 ꢂ 10
4.57 ꢂ 10
3.93 ꢂ 10
8.09 ꢂ 10
5.95 ꢂ 10
4.07 ꢂ 10
6.82 ꢂ 10
11
6.41 ꢂ 10
11
7.87 ꢂ 10
12
8.56 ꢂ 10
12
7.36 ꢂ 10
12
7.33 ꢂ 10
12
5.39 ꢂ 10
13
5.73 ꢂ 10
Fig.
4 TGA/DSC curve of polystyrene beads before and after
modification.
area is invariable before and aer dyeing. According to eqn (1)
and (2), the loadings of surface-modied polystyrene beads can
onto the surface of XAD4, indicating success of both the carbene be calculated.
ꢀ
ꢁꢀ
mol of N
ꢁ
modication and the azo coupling reaction. Similarly, the
À
Á
% of N
00
g of N
ꢁ1
Loadings mmol g
¼
modication by diazomethanes 3a and 3d with meta-substitu-
tion in the middle aryl ring shows the best modication effect,
for the same reason as that stated above. On the basis of these
results, polymer 5a was dyed with uoro-diazonium salts to give
1
g of PSXAD
ꢀ
ꢁ
1
ꢂ
1
4 g of N
ꢀ
ꢀ
ꢁ
1
mol of precursor compound
13a(f–g) and they were also found to have a relatively high
ꢂ
ꢂ
n mol of N atoms
ꢁ
content of nitrogen. When this data was used to calculate an
average value for the ratio of unmodied to modied styrene
units (N) (Table 4), it was found that the most highly modied
systems showed modication on one in every 100–200 styrenes
3
1
0 mmol
1
mol
(1)
(
e.g. samples 5d, 7a, 9a) but this dropped markedly for the less
À
Á
À
mmol
ꢁ1Á
2
efficiently modied systems.
Loadings molecules per cm ¼ loading mmol g
ꢀ
ꢀ
ꢀ
ꢀ
ꢁ
However, by contrast, nitrogen cannot be found at all in
modied polyacrylate beads. This appears to be because MAC-3
is a solid sphere rather than a porous one, and the loading
density of nitrogen then falls below the CHN detection limit.
ꢁ3
1
0
mol
ꢂ
ꢂ
ꢂ
ꢂ
1
ꢁ
2
3
6
:02 ꢂ 10 molecules
1
mol
ꢁ
1
g
3
.5 Loadings of surface-modied polymers
A cm2 of polymer
ꢁ
It is assumed that the dyeing process by diazonium salt does not
change the crosslinking of polymers but only changes the
constituent elements on the surface, and therefore the surface
2
1
m
1
04 cm2
(2)
Table 4 Elemental analysis data of modified and dyed polystyrene
beads
Using the data contained in Tables 2–4, the surface loadings
could be calculated, and are given in Table 5.
It is found that the loading levels are in the range of 9.29 ꢂ
Sample
XAD4
C%
H%
N%
N
ꢁ
3
ꢁ1
ꢁ1
11
13
1
0
to 4.07 ꢂ 10 mmol g or 6.41 ꢂ 10 to 5.73 ꢂ 10
2
89.38
84.46
85.88
85.22
90.04
90.96
91.03
88.73
89.74
89.89
90.39
91.46
89.49
89.92
7.92
6.76
7.50
7.47
7.83
7.87
8.06
7.57
7.60
7.89
7.83
8.40
7.82
8.23
<0.10
0.51
0.13
0.15
0.64
0.29
<0.10
0.22
<0.10
<0.10
1.14
<0.10
0.68
—
molecules per cm . These values are similar to other values ob-
23
7
7
7
9
9
9
1
1
1
5
5
1
1
a
b
c
a
b
c
1a
1b
1c
d
260 tained by surface modication using arylcarbenes. It seems that
1030
2
compound 3d with a functional group of –NH is the best one
for bis(arylcarbene) insertion modication, followed by the
compound 3a. Compounds 3b, 3c and 3e are not good structures.
890
200
460
>12 100
610
>1300
>1300
110
1340
190
4
. Conclusion
Polystyrene beads and polyacrylate beads, two typical organic
materials, have been examined for modication by a bis(ar-
ylcarbene) insertion reaction, followed by the azo coupling reac-
tions to produce differing but controlled surface functionality.
e
3af
3ag
0.50
260
111288 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016

View Article Online
Paper
RSC Advances
The signals of nitrogen, chlorine, and uorine in XPS spectra 11 A. Demonceau, A. F. Noels, A. J. Hubert and P. Teyssie, J.
show that the protocol is successful. Furthermore, the ratios of N/
Cl and N/F can be calculated, which are in accordance with the
Chem. Soc., Chem. Commun., 1981, 688–689, DOI: 10.1039/
c39810000688.
formula of molecules attached to the surface of polymers. 12 M. Aglietto, R. Alterio, R. Bertani, F. Galleschi and
According to the results of solid state NMR spectra, new peaks at G. Ruggeri, Polymer, 1989, 30, 1133–1136.
56.4 ppm (5a), 158.5 ppm and 115.0 ppm (5d) further conrm 13 M. Aglietto, R. Bertani, G. Ruggeri, P. Fiordiponti and
1
the signicant change of chemical structure on the surface of
A. L. Segre, Macromolecules, 1989, 22, 1492–1493.
modied polymers. BET data indicates that the surface area of 14 S. Al-Malaika, Reactive modiers for polymers, Blackie
modied polystyrenes 5a and 5d are almost cut to half compared Academic & Professional, London, 1st edn, 2012.
to the unmodied polystyrene. BJH data states that pore size 15 A. Blencowe and W. Hayes, So Matter, 2005, 1, 178.
distribution is almost unchanged before and aer modication, 16 A. Blencowe, K. Cosstick and W. Hayes, New J. Chem., 2006,
which means that the modication by bis(arylcarbene) insertion
occurs but does not block mesopores on the surface of poly- 17 A. Blencowe, C. Blencowe, K. Cosstick and W. Hayes, React.
styrene. Furthermore, the bulk property is unchanged, since the Funct. Polym., 2008, 68, 868–875.
result of TG/DSC analysis is very similar before and aer modi- 18 S. Ghiassian, H. Ismaili, B. D. Lubbock, J. W. Dube,
30, 53–58.

cation. The data of BET and Elemental analysis permits the
P. J. Ragogna and M. S. Workentin, Langmuir, 2012, 28,
12326–12333.
calculation of the loadings of surface-modied polymers, which
ꢁ
3
ꢁ1
ꢁ1
are in the range of 9.29 ꢂ 10 to 4.07 ꢂ 10 mmol g or 6.41 ꢂ 19 K. M. Awenat, P. J. Davis, M. G. Moloney and W. Ebenezer,
1
1
13
2
10
to 5.73 ꢂ 10 molecules per cm . This biscarbene-based
Chem. Commun., 2005, 990–992, DOI: 10.1039/b414856h.
modication is a useful protocol for organic materials with the 20 M. G. Moloney, J. Phys. D: Appl. Phys., 2008, 41, 174006.
promise of imparting new chemical functional groups and 21 C. Choong, J.-P. Griffiths, M. G. Moloney, J. Triffitt and
macroscopic properties to material surfaces. Moreover, this work
D. Swallow, React. Funct. Polym., 2009, 69, 77–85.
shows that the bis(arylcarbene) system is as effective as mono- 22 J. P. Griffiths, B. Maliha, M. G. Moloney, A. L. Thompson and
(arylcarbene)s, but of signicance since the starting bis-
I. Hussain, Langmuir, 2010, 26, 14142–14153.
(aryldiazomethane)s are more easily accessible and easier to 23 A. Aphaiwong, M. G. Moloney and M. Christlieb, J. Mater.
handle than the mono(aryldiazomethane)s.
Chem., 2012, 22, 24627–24636.
24 C. Choong, J. S. Foord, J.-P. Griffiths, E. M. Parker, L. Baiwen,
M. Bora and M. G. Moloney, New J. Chem., 2012, 36, 1187–
Acknowledgements
1200.
This work is nancially supported by the National Natural 25 C. L. Bagwell, D. M. L. Leonard, J.-P. Griffiths,
Science Foundation of China (No. 21406121) and the Distin-
guished Middle-Aged and Young Scientist Encourage and
M. G. Moloney, N. J. Stratton and D. P. Travers, Macromol.
React. Eng., 2014, 8, 170–180.
Reward Foundation of Shandong Province (No. BS2013CL037). 26 G. W. Nelson, E. M. Parker, K. Singh, C. F. Blanford,
M. G. Moloney and J. S. Foord, Langmuir, 2015, 31, 11086–
11096.
References
2
7 G. Sartori, R. Maggi and V. Santacroce, Arene Chemistry:
Reaction Mechanisms and Methods for Aromatic Compounds,
2015, p. 59.
1
2
3
4
5
6
7
8
9
W. Kirmse, Carbene Chemistry, Acdemic Press, New York and
London, 2nd edn, 2013.
T. Suzuki, Q. Li, K. C. Khemani, F. Wudl and O. Almarsson, J. 28 S. M. Nicolle and C. J. Moody, Chem.–Eur. J., 2014, 20, 4420–
Am. Chem. Soc., 1992, 114, 7300–7301. 4425.
A. Blencowe, N. Caiulo, K. Cosstick, W. Fagour, P. Heath and 29 S. M. Nicolle, C. J. Hayes and C. J. Moody, Chem.–Eur. J.,
W. Hayes, Macromolecules, 2007, 40, 939–949.
2015, 21, 4576–4579.
E. Jellema, A. L. Jongerius, J. N. Reek and B. de Bruin, Chem. 30 H. Liu, Y. Wei and C. Cai, New J. Chem., 2016, 40, 674–678.
Soc. Rev., 2010, 39, 1706–1723.
31 M. I. Javed and M. Brewer, Org. Lett., 2007, 9, 1789–1792.
C. Wu, F. Hu, Z. Liu, G. Deng, F. Ye, Y. Zhang and J. Wang, 32 C. Perusqu ´ı a-Hern ´a ndez, G. R. Lara-Issasi, B. A. Frontana-
Tetrahedron, 2015, 71, 9196–9201.
T. Sugawara, M. Inada and H. Iwamura, Tetrahedron Lett.,
Uribe and E. Cuevas-Ya n˜ ez, Tetrahedron Lett., 2013, 54,
3302–3305.
33 D. Leonard, M. G. Moloney and C. Thompson, Tetrahedron
Lett., 2009, 50, 3499–3502.
34 D. K. Kolmel, B. Rudat, D. M. Braun, C. Bednarek,
U. Schepers and S. Brase, Org. Biomol. Chem., 2013, 11,
3954–3962.
1
983, 24, 1723–1726.
T. Sugawara, D. Bethell and H. Iwamura, Tetrahedron Lett.,
984, 25, 2375–2378.
1
M. Okimoto, K. Numata, K. Tomozawa, T. Shigemoto,
M. Hoshi and Y. Takahashi, Aust. J. Chem., 2005, 58, 560–563.
M. Matsushita, T. Momose, T. Shida, Y. Teki, T. Takui and 35 S. p. Desrousseaux, B. Bennetau, J.-P. Morand,
K. Itoh, J. Am. Chem. Soc., 1990, 112, 4700–4702.
0 Y. Teki, T. Takui, T. Kinoshita, K. Itoh, M. Matsushita,
C. Mingotaud, J.-F. L ´e tard, S. b. Montant and E. Freysz,
New J. Chem., 2000, 24, 977–985.
1
T. Nakamura, T. Momose and T. Shida, Mol. Cryst. Liq. 36 R. Kaminski, U. Lauk, P. Skrabal and H. Zollinger, Helv.
Cryst., 1993, 232, 271–288. Chim. Acta, 1983, 66, 2002–2017.
This journal is © The Royal Society of Chemistry 2016
RSC Adv., 2016, 6, 111276–111290 | 111289

View Article Online
RSC Advances
Paper
3
3
3
7 P. Doppelt, G. Hallais, J. Pinson, F. Podvorica and 40 S. Kango, S. Kalia, A. Celli, J. Njuguna, Y. Habibi and
S. Verneyre, Chem. Mater., 2007, 19, 4570–4575. R. Kumar, Prog. Polym. Sci., 2013, 38, 1232–1261.
8 P. Meares, Polymers: structure and bulk properties, Van 41 E. Jakab, M. A. Uddin, T. Bhaskar and Y. Sakata, J. Anal. Appl.
Nostrand Reinhold, 1965.
Pyrolysis, 2003, 68–69, 83–99.
9 P. Roach, D. Eglin, K. Rohde and C. C. Perry, J. Mater. Sci.:
Mater. Med., 2007, 18, 1263–1277.
111290 | RSC Adv., 2016, 6, 111276–111290
This journal is © The Royal Society of Chemistry 2016