Synthesis of new bipyridine-containing polystyrene derived from 1,10-phenanthroline

Article abstract of DOI:10.3184/030823409X401853

This report describes the synthesis of two new bipyridine-containing polystyrene compounds from 1,10-phenanthroline by four steps.

Full text of DOI:10.3184/030823409X401853

JOURNAL OF CHEMICAL RESEARCH 2009
FEBRUARY, 101–103
RESEARCH PAPER 101
Synthesis of new bipyridine-containing polystyrene derived from
1,10-phenanthroline
Hui Cang, Siqing Wang, Wenzhong Yang and Jintang Wang*
College of Science, Nanjing University of Technology, Nanjing, 210009, P.R.China
This report describes the synthesis of two new bipyridine-containing polystyrene compounds from 1,10-phenanthroline
by four steps.
Keywords: 1,10-phenanthroline, bipyridine-containing polystyrene, metal containing polymer
In recent years, functional polystyrene has received special
attention and has been investigated extensively for polymer-
supported catalysts,1 supramolecular polymers,2 and polymeric
receptors.3 In the meantime, the synthesis of metal containing
polymers has attracted considerable attention due to their
PDQ\ꢀDSSOLFDWLRQVꢀLQꢀWKHꢀ¿HOGVꢀRIꢀFDWDO\VLVꢁ4 conducting and
photoresponsive materials5 and supramolecular chemistry.6
Bipyridyl compounds such as 2,2'-bipyridine, 1,10-
phenanthroline, and their derivatives are also strong bidentate
chelating7 and bridging agents8 which have been widely
H[SORUHGꢀGXHꢀWRꢀWKHLUꢀHDV\ꢀDFFHVVLELOLW\ꢁꢀHDV\ꢀPRGL¿FDWLRQꢀDQGꢀ
relative air stability.9 Therefore, some bipyridine-containing
ligands were synthesised and used for preparation of metal
containing polymers(MCPs).10
Here we report on the synthesis of two new bipyridine-
containing polystyrene compounds starting from 1,10-
phenanthroline as shown in Scheme 1, which will be explored in
WKHꢀDUHDꢀRIꢀFDWDO\WLFꢀDQGꢀÀXRUHVFHQWꢀPHWDO±RUJDQLFꢀFRRUGLQDWLRQꢀ
polymers in a further study. The ratio of monomer 3/styrene was
1/2 in the reaction of monomer 3 with styrene. The products
4a and 4bꢀDUHꢀVROLGꢁꢀVHSDUDWHGꢀDQGꢀSXUL¿HGꢀHDVLO\ꢀIURPꢀVW\UHQHꢂꢀ
Furthermore, 1H NMR spectra show that there is no unsaturated
double bond (ArCH=CH2) in the product, which indicates that
there is no compound 3 in the solid material. So, in the unit of
4a and 4b, m/n = should be 2/1.
Experimental
All reagents and solvents were purchased commercially as AC grade
DQGꢀZHUHꢀXVHGꢀZLWKRXWꢀIXUWKHUꢀSXUL¿FDWLRQꢀXQOHVVꢀQRWHGꢂꢀ(WKDQROꢀDQGꢀ
'0)ꢀZHUHꢀGULHGꢀRYHUꢀꢃꢀǖꢀDFWLYDWHGꢀPROHFXODUꢀVLHYHVꢀSULRUꢀWRꢀXVHꢂꢀ
Melting points were determined in open capillaries and uncorrected.
Mass spectra were made with LC-MSD-Trap-SL. Elemental analyses
ZHUHꢀREWDLQHGꢀ(OHPHQWDUꢀ9DULRꢀ(/ꢀɒꢁꢀDQGꢀDꢀFDOFXODWHGꢀUHVXOWꢀZDVꢀ
based on the 2:1 ratio. 1H NMR spectra were obtained with a Varian
XL300 spectrometer. The IR spectra were determined as potassium
bromide pellets on a Bruker Equinox55 FT-IR spectrophotometer.
TGA and DSC were carried out on a Netzsch STA 409 PG/PC and
on a DS822 under air atmosphere, respectively. GPC analysis was
conducted with a Shimadzu LC-6A.
6\QWKHVLVꢀRIꢀꢁꢂꢃꢄGLD]DÀXRUHQꢄꢅꢄRQH (dafo) 1: Light yellow needle
obtained by oxidation of 1,10-phenanthroline with KMnO4 in a
KOH solution following a literature method.11 M.p. 215–216°C MS:
m/z = 182.23. 1H NMR (CDCl3, 300 MHz, relative to TMS): G8.81
(dd, 2H, J1 = 5.1, J2 = 1.5 Hz, pyridyl H ortho to N), 8.01 (dd, 2H,
J1 = 5.1, J2 = 1.5 Hz, pyridyl H para to N), 7.36 (t, 2H, J1 = 7.6,
J2 = 5.1 Hz, pyridyl H ortho to N).
N
N
N
N
N
N
CH3COOH
EtOH
KMnO 4
KO H
Cl
R1
N
O
NaH/DMF,18-crown-6
2
2a:
R1= OH
1
2b: R1= COOH
m
n
N
N
N
N
O
N
N
O
AIBN
4a
3a:
3 : styrene
1 : 2
m
n
O
N
N
O
C
N
N
C
O
O
N
AIBN
N
3b
4b
Scheme 1
* Correspondent. E-mail: wjt@njut.edu.cn

102 JOURNAL OF CHEMICAL RESEARCH 2009
Synthesis of ligand 2: A mixture of compound 1 (455 mg,
2.5 mmol), glacial acetic acid (0.25 mL, 2.5 mmol), ethanol (20 mL)
DQGꢀDQLOLQHꢀGHULYDWLYHVꢀꢄꢅꢀPPROꢆꢀZHUHꢀKHDWHGꢀXQGHUꢀUHÀX[ꢀIRUꢀꢇꢈꢀKꢁꢀ
DQGꢀ WKHQꢀ WKHꢀ GHVLUHGꢀ SUHFLSLWDWHꢀ ZDVꢀ ¿OWHUHGꢁꢀ ZDVKHGꢀ ZLWKꢀ HWKDQROꢀ
three times and then dried in vacuum oven at 50°C.
C, 77.70; H, 4.55; N, 10.10%. 1H NMR (CDCl3, 300 MHz, relative to
TMS): G8.83 (dd, 1H, J1 = 4.8, J2 = 1.5 Hz, pyridyl H ortho to N), 8.66
(dd, 1H, J1 = 4.8, J2 = 1.5 Hz, pyridyl H ortho to N), 8.26 (dd, 1H,
J1 = 7.6, J2 = 1.5 Hz, pyridyl H para to N), 7.96 (d, 2H, J = 8.5 Hz,
ArH), 7.58 (t, 1H, J1 = 7.6, J2 = 4.8 Hz, pyridyl H ortho to N), 7.28
(t, 1H, J1 = 7.6, J2 = 4.8 Hz, pyridyl H ortho to N), 7.15 (d, 2H,
J = 8.5 Hz, ArH), 7.07 (d, 2H, J = 7.3 Hz, ArH), 6.93 (d, 2H, J = 7.3
Hz, ArH), 6.83 (dd, 1H, J1 = 7.6, J2 = 1.5 Hz, pyridyl H para to N),
6.65 (dd, 1H, J1 = 17.1, J2 = 10.6 Hz, =CH), 5.83 (d, 1H, J = 17.1
Hz, =CH2), 5.30 (d, 1H, J = 10.6 Hz, =CH2), 5.10 (s, 2H, O-CH2).
IR (KBr): 3036, 1673, 1641, 1592, 1560, 1400 cm-1.
ꢅꢄꢆꢁꢄ+\GUR[\DQLOLQRꢇꢄꢁꢂꢃꢄGLD]DÀXRUHQH 2a (607 mg, 89%):
M.p.>300°C. MS: m/z = 272.85. Elemental analysis Calcd for
C
17H11N3O: C, 74.71; H, 4.06; N, 15.38. Found: C, 74.65; H, 4.00;
N, 15.42%. 1H NMR (CDCl3, 300 MHz, relative to TMS): G9.53 (s,
1H, –OH), 8.79 (dd, 1H, J1 = 4.9, J2 = 1.5 Hz, pyridyl H ortho to N),
8.67 (dd, 1H, J1 = 4.9, J2 = 1.5 Hz, pyridyl H ortho to N), 8.27 (dd,
1H, J1 = 7.6, J2 = 1.5 Hz, pyridyl H para to N), 7.54 (t, 1H, J1 = 7.6,
J2 = 4.9 Hz, pyridyl H ortho to N), 7.27 (t, 1H, J1 = 7.6, J2 = 4.9 Hz,
pyridyl H ortho to N), 7.13 (dd, 1H, J1 = 7.6, J2 = 1.5 Hz, pyridyl
H para to N), 6.90 (m, 4H, ArH). IR (KBr): 3144, 3038, 1638, 1646,
1592, 1561, 1401 cm-1.
Synthesis of bipyridine-containing polymer 4: To a THF solution
of monomer 3 (1.2 mmol in 3 mL) was added AIBN (0.028 g,
0.18 mmol) and styrene (255 mg, 2.4 mmol). The solution was
purged with argon thoroughly. Polymerisation was carried out for
48 h at 75°C. After cooling to room temperature the polymer was
¿UVWꢀ SUHFLSLWDWHGꢀ E\ꢀ DGGLWLRQꢀ WRꢀ PHWKDQROꢀ IROORZHGꢀ E\ꢀ KH[DQHꢂꢀ
7KHꢀSUHFLSLWDWHꢀZDVꢀ¿OWHUHGꢀDQGꢀGULHGꢀLQꢀYDFXXPꢀDWꢀꢈꢉ°C to give the
polymer 4.
ꢅꢄꢆꢁꢄ&DUER[\DQLOLQRꢇꢄꢁꢂꢃꢄGLD]DÀXRUHQHꢀ 2b (640 mg, 85%):
M.p.>300°C. MS: m/z = 300.99. Elemental analysis: Calcd for
C
18H11N3O2: C, 71.75; H, 3.68; N, 13.95. Found: C, 71.70; H, 3.63;
N, 13.89%. 1H NMR (CDCl3, 300 MHz, relative to TMS): G12.93 (s,
1H, –COOH), 8.82 (dd, 1H, J1 = 4.9, J2 = 1.5 Hz, pyridyl H ortho
to N), 8.68 (dd, 1H, J1 = 4.9, J2 = 1.5 Hz, pyridyl H ortho to N),
8.29 (dd, 1H, J1 = 7.7, J2 = 1.5 Hz, pyridyl H para to N), 8.02 (d,
2H, J = 8.6 Hz, ArH), 7.56 (t, 1H, J1 = 7.7, J2 = 4.9 Hz, pyridyl H
ortho to N), 7.24 (t, 1H, J1 = 7.7, J2 = 4.9 Hz, pyridyl H ortho to N),
7.17 (d, 2H, J = 8.6 Hz, ArH), 6.83 (dd, 1H, J1 = 7.7, J2 = 1.5 Hz,
pyridyl H para to N). IR (KBr): 3094, 3032, 1702, 1643, 1646, 1598,
1398 cm-1.
4a (635 mg, 88%): Elemental analysis: Calcd for polymer 4a
(C26H19N3O)n(C8H8)m (m/n = 2/1): C, 84.42; N, 7.04; H, 5.86. Found:
C, 84.50; H, 5.96; N, 6.83%. The concentration of the bipyridine
was 1.63 mmol/g [6.83/(3 u 14.00) u 100]. 1H NMR (CDCl3, 300
MHz, relative to TMS): G8.89 (d, 1H, J1 = 5.1, pyridyl H ortho to
N), 8.68 (d, 1H, J1 = 5.0, pyridyl H ortho to N), 8.28 (d, 1H, J1 = 7.6,
pyridyl H para to N), 7.40–6.45 (m, broad signal due to the polymer
resonance), 5.12 (s, 2H, O–CH2), 1.85–1.21 (m, broad signal due to
the polymer resonance). IR (KBr): 3042, 2928, 1632, 1606, 1596,
1551, 1402 cm-1.
Synthesis of monomer 3: To an ice cooled solution of ligand
2 (2 mmol) in dry DMF (30 mL) was added NaH (120 mg,
3 mmol, 1.5 equiv., as 60% purity in oil) and 18–crown-6 (catalytic
amount), then the mixture was stirred at this temperature for 30 min.
4-Vinylbenzylchloride (0.3 mL, 2.2 mmol) was then added dropwise
at this temperature and the solution was allowed to warm to room
temperature. After stirring for 24 h, the resulting mixture was poured
carefully into water (100 mL). The product was extracted with
ethyl acetate, dried over anhydrous Na2SO4 and concentrated. Flash
column chromatography (SiO2, ethyl acetate/petroleum ether (60–90)
1/2) afforded monomer 3.
4b (650 mg, 86%): Elemental analysis: Calcd for polymer 4b
(C27H19N3O)n(C8H8)m (m/n = 2/1): C, 82.56; H, 5.60; N, 6.72. Found:
C, 82.55; H, 5.83; N, 6.50%. The concentration of the bipyridine was
1.55 mmol/g [6.50/(3 u 14.00) u 100]. 1H NMR (CDCl3, 300 MHz,
relative to TMS): G8.86 (d, 1H, J1 = 5.0, pyridyl H ortho to N), 8.60
(d, 1H, J1 = 5.0, pyridyl H ortho to N), 8.23 (d, 1H, J1 = 7.6, pyridyl
H para to N), 7.93 (d, 2H, J = 8.4 Hz, Ar), 7.45–6.45 (m, broad signal
due to the polymer resonance), 5.10 (s, 2H, O–CH2), 1.86–1.20 (m,
broad signal due to the polymer resonance). IR (KBr): 3048, 2923,
1672, 1636, 1592, 1399 cm-1.
ꢅꢄ>ꢁꢄꢆꢁꢈꢄ9LQ\OEHQ]\OR[\ꢇDQLOLQR@ꢄꢁꢂꢃꢄGLD]DÀXRUHQH 3a (670 mg,
86%): M.p. 230–232°C. MS: m/z = 389.10. Elemental analysis
Calcd for C26H19N3O: C, 80.18; H, 4.92; N, 10.79. Found: C,
80.24; H, 4.88; N, 10.80%. 1H NMR (CDCl3, 300 MHz, relative to
TMS): G8.80 (dd, 1H, J1 = 4.8, J2 = 1.5 Hz, pyridyl H ortho to N),
8.65 (dd, 1H, J1 = 4.8, J2 = 1.5 Hz, pyridyl H ortho to N), 8.26 (dd,
1H, J1 = 7.6, J2 = 1.5 Hz, pyridyl H para to N), 7.58 (t, 1H,
J1 = 7.6, J2 = 4.8 Hz, pyridyl H ortho to N), 7.25 (t, 1H, J1 = 7.6,
J2 = 4.8 Hz, pyridyl H ortho to N), 7.10 (m, 3H, ArH and pyridyl
H para to N), 6.89 (m, 6H, ArH), 6.70 (dd, 1H, J1 = 17.1,
J2 = 10.6 Hz, =CH), 5.80 (d, 1H, J = 17.1 Hz, =CH2), 5.32 (d, 1H,
J = 10.6 Hz, =CH2), 5.01 (s, 2H, O–CH2). IR (KBr): 3033, 1669,
1616, 1593, 1565, 1404 cm-1.
Properties of bipyridine-containing polymer 4
The polystyrenes were characterised by IR, 1H NMR and elemental
analysis. The properties of bipyridine-containing polymer 4 were
listed in Tables 1 and 2, and the TGA and DSC curves of the
desired bipyridine-containing polymers were shown in Figs 1 and 2,
respectively. GPC results showed that the new polymers had narrow
molecular weight distributions. The thermal degradation of 4a and
ꢅꢄ>ꢁꢄꢆꢁꢈꢄ9LQ\OEHQ]\OEHQ]RDWHꢇDQLOLQR@ꢄꢁꢂꢃꢄGLD]DÀXRUHQH
3b
(750 mg, 90%): M.p.: 235–237°C. MS: m/z = 417.10. Elemental
analysis Calcd for C27H19N3O: C, 77.68; H, 4.59; N, 10.07. Found:
Table 1 Solubility in various solvents
Polymer
THF ethanol CHCl3 DMF Toluene DMSO
4a
4b
+ +
+ +
-
-
+ +
+ +
+ +
+ +
+
+
+ -
+ -
+ + : absolutely soluble at 25°C, + : mainly soluble at 25°C and
absolutely soluble at 50°C.
+ -: insoluble at 25°C and mainly soluble at 50°C, -: insoluble
at 25°C and 50°C.
Fig. 1 TGA curves of polymer 4.
Table 2 GPC and thermal analysis of the bipyridine-containing polystyrenes
Polymer
GPCa
Thermal analysis
Mn(g/mol)
MW(g/mol)
Mw/Mn
Td/°Cb
Tg/°Cc
4a
4b
6853
7035
8402
9005
1.23
1.28
322
340
175
183
aAs calibrated against linear polystyrene strands with low polydispersity index. The eluent for samples was THF. Mw: Weight
average molecular weight; Mn: Number average molecular weight.
bTd was determined by TGA at a heating rate of 20°C min-1.
cTg was conducted by DSC at a heating rate of 10°C min-1.

JOURNAL OF CHEMICAL RESEARCH 2009 103
Received 27 October 2008; accepted 4 December 2008
Paper 08/0265 doi: 10.3184/030823409X401853
Published online: 24 February 2009
References
1
2
3
4
5
Y.D. Wan, C.F. Lu, G.H. Yang and Z.X. Chen, J. Chem. Res., 2007, 84.
T. Park and S.C. Zimmerman, J. Am. Chem. Soc., 2006, 128, 11582.
S. Striegler, Tetrahedron, 2001, 57, 2349.
D. Jayaprakash and H. Sasai, Tetrahedron: Asymmetry, 2001, 12, 2589.
M. Chris Shuk Kwan and C. Wai Kin, +LJKO\ꢀ HI¿FLHQWꢀ 2/('Vꢀ ZLWKꢀ
phosphorescent materials, 2008, 329.
Fig. 2 DSC curves of polymer 4.
6
7
8
V. Cádiz, Macromol. Chem. Phys., 2007, 208, 2578.
M. Querol, H. Stoekli-Evans and P. Belser, Org. Lett., 2002, 4, 1067.
Y. Wang, W. Perez, G.Y. Zheng, D.P. Rillema and C.L. Huber, Inorg.
Chem., 1998, 37, 2227.
4b started at above 300°C, which indicated that 4a and 4b have
good thermally stability. The TGA curves of polymer 4 presented
two weight loss stages, which can be assigned to the loss of ligand
2 and the polystrene decomposition. Meanwhile, in Fig. 2, further
two broad exothermic peaks were observed in the DSC curves at
about 350°C due to the rupture of polymer molecular chains already
considered in the curves of TGA.
9
I.R. Butler, Organometallics, 1992, 11, 74.
10 X. Schultze, J. Serrin, A. Adronov and J.M. Frechet, J. Chem. Commun,
2001, 1160.
11 L.J. Henderson, Jr. F.R. Fronczek and W.R. Cherry, J. Am. Chem. Soc.,
1984, 106, 5876.