Synthesis and characterization of novel solid polymer electrolytes based on poly(7-oxanorbornenes) with pendent oligoethyleneoxy-functionalized cyclotriphosphazenes

Article abstract of DOI:10.1021/ma0217478

The development of novel cyclotriphosphazene and oligoethyleneoxy-functionalized poly-(7-oxanorbornenes) for possible use as solid polymer electrolytes in the electrolyte layer of rechargeable lithium batteries is described. The length of the oligoethylen

Full text of DOI:10.1021/ma0217478

Macromolecules 2003, 36, 3563-3569
3563
Synthesis and Characterization of Novel Solid Polymer Electrolytes
Based on Poly(7-oxanorbornenes) with Pendent
Oligoethyleneoxy-Functionalized Cyclotriphosphazenes
Ha r r y R. Allcock ,* J a r ed D. Ben d er , Rober t V. Mor for d , a n d Er ik B. Ber d a
Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory,
University Park, Pennsylvania 16802
Received December 9, 2002; Revised Manuscript Received March 30, 2003
ABSTRACT: The development of novel cyclotriphosphazene and oligoethyleneoxy-functionalized poly-
(7-oxanorbornenes) for possible use as solid polymer electrolytes in the electrolyte layer of rechargeable
lithium batteries is described. The length of the oligoethyleneoxy group on the cyclotriphosphazene has
been varied, and the effects on ion transport were studied. The synthesis of 5-[2-(2-methoxyethoxy)-
ethoxymethyl]-7-oxanorbornene and 5-[2-(2-methoxyethoxy)ethoxymethyl]norbornene, their polymerization
through ring-opening metathesis polymerization, and the characterization of the polymers are also
discussed to illustrate the effect of oxygen atoms in the polymer backbone and in the cyclotriphosphazene
side groups on the thermal and ion transport properties of these materials.
In tr od u ction
The development of small, lightweight, powerful, safe,
environmentally benign, and portable energy sources
has received a great deal of attention during the past
1
-5
few decades.
The rechargeable lithium battery is a system that has
received considerable attention due to its low density
and the low oxidation potential of lithium. The devel-
F igu r e 1. Polymer electrolytes.
2′-methoxyethoxy)ethoxy)phosphazene] (MEEP), 2, was
6
opment of liquid-free rechargeable lithium batteries that
contain a polymeric electrolyte is a particular challenge.
These could potentially yield batteries that are smaller,
lighter, easier to manufacture, and contain less toxic
(
12
developed nearly 20 years ago. When 2 is complexed
with a lithium salt, the ion transport is several orders
of magnitude higher than that of materials based on
poly(ethylene oxide). However, MEEP-based solid poly-
mer electrolytes are amorphous gums at room temper-
ature rather than solids, and recent efforts have been
focused on the design and synthesis of polymers with
both high ion transport and better dimensional stability.
Recently, we have published reports that describe the
1
compounds. Numerous reports have been published on
the advances in the field of solid-state lithium batter-
ies.1
,3,6,7
Existing anode and cathode materials perform
8
,9
at acceptable levels.
However, the available solid
polymer electrolytes do not yet possess the required
combination of properties. Therefore, recent efforts have
been focused on the design and synthesis of polymeric
electrolytes in which the lithium ion transport is
use of polynorbornenes with cyclophosphazene side
18,19
groups as solid polymer electrolytes.
The cyclotri-
-
3
1
adequate for modern applications (10 S/cm).
phosphazene units are designed to serve as a platform
In 1973, poly(ethylene oxide) (PEO) (Figure 1), 1, was
shown to form complexes with metal salts,10 and this
suggested its use as a possible electrolyte for lithium
for multiple oligoethylene oxide substituents which
23-25
themselves should promote ion transport.
Polynor-
bornenes often yield amorphous materials due to the
many stereo- and regioisomers present. The earlier
materials prepared by us had ion transport levels
comparable to materials based on 2, but with better
mechanical properties.
Work by Grubbs et al. indicated that poly(7-oxanor-
bornenes) exist in a variety of microstructures which
1
1
batteries. However, lithium cation transport in this
polymer is hindered at temperatures below 80 °C due
1
to the presence of crystalline domains. Subsequently,
research has emphasized the development of amorphous
materials which provide facile lithium ion transport and
1
show good chemical, mechanical, and thermal stability.
Phosphazene-based electrolytes have received a great
can interact with metal cations via the oxygen in the
1
2-20
26,27
deal of attention.
The phosphazene system is a well-
polymer backbone.
Thus, it was of interest to
known hybrid inorganic-organic polymer platform with
determine whether the poly(7-oxanorbornene) skeleton
provides an advantage over the polynorbornene back-
bone in polymers with pendent oligoethyleneoxy side
chains. Here we describe the synthesis, characterization,
structure-property relationships, and ionic conductivity
of polymer electrolytes based on (a) side chain oligoet-
hyleneoxy-functionalized poly(7-oxanorbornenes) and (b)
poly(7-oxanorbornenes) with pendent cyclotriphospha-
zene units that themselves bear five oligoethyleneoxy
units per ring. The multiple oligoethyleneoxy pendent
different properties generated by a variety of organic
2
1,22
side groups.
Chemical stability and materials flex-
ibility are imparted by the phosphazene skeleton, while
the organic side groups can facilitate ion pair separation,
1
2
lithium cation coordination, and ion transport. The
first phosphazene lithium cation conductor, poly[bis(2-
*
Corresponding author: Fax 814-865-3314; Tel 814-865-3527;
e-mail hra@chem.psu.edu.
1
0.1021/ma0217478 CCC: $25.00 © 2003 American Chemical Society
Published on Web 04/26/2003

3
564 Allcock et al.
Macromolecules, Vol. 36, No. 10, 2003
Sch em e 1. Rou tes to P h osp h a zen e-Ba sed Mon om er s
-8
Sch em e 2. Syn th esis of P h osp h a zen e-F r ee Mon om er s
9 a n d 10
6
oligoethyleneoxy nucleophiles afforded pure monomers
6
and 8. Although route A suffered from the need for
an extra purification step to remove the hexa-substi-
tuted product, all the monomers were obtained in
satisfactory yields as transparent viscous oils.
The syntheses of the totally organic monomers 9 and
0 are shown in Scheme 2. Similar monomers have been
1
prepared and polymerized, although through a different
3
0
synthetic approach. First, the sodium salt of either 3a
or 3b was prepared, followed by addition of 2-(2-
1
4
methoxyethoxy)ethyl p-toluenesulfonate at -78 °C.
Following purification, the desired monomers (mixture
of exo and endo isomers) were obtained in good yields
as transparent oils.
groups should serve as a facile vehicle for cation
transport. A second objective was to examine the role
played by the oxygen atoms in the backbone as supple-
mental cation coordination sites. The behavior of these
polymers was compared to that of the totally organic
counterparts that lacked the phosphazene side groups
but have linear oligoethyleneoxy side chains instead.
3
. P olym er Syn th esis. Polymers 11-15 were pre-
pared at ambient temperature, under inert atmosphere
conditions, through ring-opening metathesis polymeri-
zation of the corresponding monomers using a monomer:
catalyst ratio of 275:1 [Cl2(PCy3)2RuCHPh]. Immedi-
ately following the addition of [Cl2(PCy3)2RuCHPh] in
a minimal amount of dichloromethane, the solutions
became progressively more viscous as the polymeriza-
tion proceeded. All the polymerizations were terminated
after 12 h by the addition of 0.5 mL of ethyl vinyl ether.
The solutions were then diluted with tetrahydrofuran
or methanol and were dialyzed against tetrahydrofuran
and methanol. Following the removal of the solvent,
polymers 11-13 were obtained in good yields as adhe-
sive gums, whereas polymers 14 and 15 were obtained
as solid elastomers. All the polymers were readily
soluble in common organic solvents such as tetrahydro-
furan, dichloromethane, methanol, and chloroform.
4. Solid P olym er Electr olytes. (a) Thermal Analy-
sis. The morphological properties of the totally organic
polymers and hybrid solid polymer electrolytes were
examined by differential scanning calorimetry (DSC).
In the following discussion, species 16 is the polymer
salt complex from polymer 11, while 17 is from polymer
12, 18 is from 13, 19 is from the oxanorbornene-
phosphazene-free system 14, and 20 is from the nor-
bornene-phosphazene-free system 15 (Table 1). All
polymers and solid polymer electrolytes were amorphous
over the entire temperature range studied (-100 to 50
°C). The presence of the phosphazene moiety depresses
the glass transition temperature (Tg) significantly, as
does an increase in the length of the oligoethyleneoxy
side groups (compare 11, 12, 13, and 14 in Table 1). As
the length of the side groups increases, the polymers
develop more free volume, macromolecular motion is
increased, and the Tg is depressed. The presence of the
oxygen unit in the backbone raises the Tg compared to
the polynorbornene counterparts (compare 14 and 15
in Table 1). Presumably, the oxygen atoms in the main
Resu lts a n d Discu ssion
1
. P r in cip les In volved . Poly(7-oxanorbornenes) with
pendent oligoethyleneoxy-functionalized cyclotriphos-
phazene side units (polymers 11-13) have been pre-
pared and studied for potential use in the electrolyte
layer of solid-state rechargeable lithium batteries. Poly-
mers 9 and 10, which lack the cyclotriphosphazene side
units, were investigated as controls to study the effect
of the oxygen atoms in the polymer backbone and pres-
ence of the cyclotriphosphazene on ionic conductivity.
2
. Mon om er Syn th esis. The synthesis of the mono-
mers required the preparation of the precursor 7-oxa-
-norbornene-2-methanol, 3a . A Diels-Alder reaction
5
between furan and methyl acrylate in the presence of
zinc iodide yielded methyl 7-oxa-5-norbornene-2-car-
boxylate (2:1 exo/endo).28 The reduction of this com-
pound with LiAlH4 in diethyl ether yielded the desired
2
9
precursor, 3a , as a 2:1 mixture of exo/endo isomers
which was used in subsequent reactions without further
purification.
Two different synthetic routes were employed to
produce monomers 6-8. The traditional method (route
A, Scheme 1, used for the synthesis of 7)1
8,19
involved
the reaction of hexachlorocyclotriphosphazene (NPCl2)3,
, with the oligoethyleneoxy nucleophile to give a
4
mixture of penta- and hexa-substituted derivatives.
Further treatment with the sodium salt of 3a yields
monomer 7 with a significant amount of the hexa-
oligoethyleneoxy cyclotriphosphazene which was re-
moved via column chromatography. In route B, treat-
ment of (NPCl2)3 with the sodium salt of 3a gave a
mixture of mono- and unsubstituted (NPCl2)3. The
(NPCl2)3 was removed by sublimation to give a purer
monosubstituted product, 5. Treatment of 5 with the

Macromolecules, Vol. 36, No. 10, 2003
Novel Solid Polymer Electrolytes 3565
Sch em e 3. P olym er iza tion of Mon om er s 6-10 to
P olym er s 11-15
F igu r e 2. Temperature-dependent ionic conductivity for solid
polymer electrolytes 16a -f.
Ta ble 1. Th er m a l Da ta a n d Sa lt Con cen tr a tion s for
P olym er s 11-15 a n d Solid P olym er Electr olytes 16a -f to
F igu r e 3. Temperature-dependent ionic conductivity for solid
polymer electrolytes 17a -f.
2
0a -f
mol %
LiN(SO2CF3)2
solid polymer
electrolyte
polymer
Tg (°C)
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
3
3
3
3
3
3
3
4
4
4
4
4
4
4
5
5
5
5
5
5
5
0
10
20
30
40
50
60
0
10
20
30
40
50
60
0
10
20
30
40
50
60
0
10
20
30
40
50
60
0
-47
-50
-37
-33
-33
-30
-25
-68
-61
-59
-51
-48
-46
-44
-70
-70
-67
-63
-61
-57
-54
-45
-37
-10
-6
16a
16b
16c
16d
16e
16f
17a
17b
17c
17d
17e
17f
F igu r e 4. Temperature-dependent ionic conductivity for solid
polymer electrolytes 18a -f.
increase did not occur for the materials based on 11 or
13. In 11, at low salt concentrations the short oligoeth-
yleneoxy chains do not impart significant free volume
to the system (compare 11, 14, and 15, in Table 1.) Thus,
the influence of the salt at low concentrations is that of
a plasticizer rather than cross-linker. For 13, a concen-
tration of 10 mol % salt is too low for lithium cations to
generate significant ionic cross-linking, to reduce the
mobility of the polymer, or to raise the Tg. The Tg’s for
the phosphazene-free systems (19a -f, 20a -f) increased
more dramatically as salt was added than did the values
of the phosphazene-based solid polymer electrolytes
(16-18). Fewer coordination sites are present in these
phosphazene-free polymers. Hence, the formation of
ionic cross-links has a more profound effect on the
internal motion at lower salt concentrations in the
phosphazene-free systems.
18a
18b
18c
18d
18e
18f
19a
19b
19c
19d
19e
19f
-5
-4
-3
-54
-29
-14
-6
10
20
30
40
50
60
20a
20b
20c
20d
20e
20f
-6
-4
-4
4
. Solid P olym er Electr olytes. (b) Temperature-
chain increase the polarity of the polymer and enhance
dipole-dipole interactions. Thus, the polymer becomes
less flexible.
As shown in Table 1, the glass transition tempera-
tures generally increase with increases in the concen-
tration of added lithium salt. This is due to transient
ionic cross-links formed between the lithium cations and
the oxygen atoms in the polymer. However, this Tg
Dependent Ionic Conductivity. The results of the tem-
perature-dependent ionic conductivity studies of solid
polymer electrolytes 16a -f to 20a -f are shown in
Figures 2-6. The conductivities increase with increas-
ing temperature in a nonlinear manner that is typi-
cal of solid polymer electrolytes. The ionic conductivi-
ties are higher when the cyclotriphosphazene moiety
is present and increase with increased length of oligo-
3
1

3
566 Allcock et al.
Macromolecules, Vol. 36, No. 10, 2003
ionic cross-links may be disrupted, and ion transport is
increased. The absence of oxygen in the backbone of
phosphazene-free systems 20a -f limits the ion solvation
by the polymer to the oxygen atoms in the pendent
oligoethylene oxide chains. Consequently, at lower tem-
peratures, low concentrations of salt generate the best
conductivities because high concentrations of salt will
induce ionic cross-linking of the system under these
conditions.
Con clu sion s
F igu r e 5. Temperature-dependent ionic conductivity for solid
polymer electrolytes 19a -f.
The synthesis of poly(7-oxanorbornenes) with pendent
oligoethyleneoxy-functionalized cyclotriphosphazenes has
been achieved via ROMP techniques to yield organic-
soluble, high molecular weight polymers in good yields.
These polymers have some of the highest molecular
weights and are among the most polar molecules to be
produced via ROMP, and this illustrates the compat-
ibility of the heteroatom-rich, oligoethyleneoxy-func-
tionalized cyclotriphosphazenes with olefin metathesis
catalysts. Lithium ion transport in these materials is
similar to that in norbornene-based materials.1
8,19
The
introduction of the oxygen atoms into the backbone of
polynorbornenes raises the glass transition temperature
which often lowers ionic conductivity, but the skeletal
oxygen atoms also facilitate lithium ion transport. The
linkage of the pendent cyclotriphosphazene ring to poly-
F igu r e 6. Temperature-dependent ionic conductivity for solid
polymer electrolytes 20a -f.
(
7-oxanorbornenes) depresses the glass transition tem-
ethyleneoxy unit (compare Figures 2-5). The conduc-
perature and also introduces more coordination sites,
thereby improving lithium ion transport significantly.
The highest conductivities found for these polymer-salt
systems suggest that gel electrolytes with a minimal
amount of coordinative organic solvent present may
provide property combinations that are superior to those
of existing gel systems.
tivities are similar to those of the norbornene-based
materials.1
8,19
As the side groups become longer (de-
pressing Tg and increasing macromolecular motion) and
as the number of coordination sites increases, the
lithium cations can be transported more efficiently. For
the phosphazene-based systems, the Tg data correlate
well with the ionic conductivity data. However, the
presence of oxygen in the backbone of the phosphazene-
free polymers increases both the glass transition tem-
perature (see above) and the ionic conductivity (compare
Figures 5 and 6). Presumably, the oxygen in the
backbone provides coordination sites in addition to those
in the side chains, and these sites can aid the transport
of lithium cations as is evident from the conductivity
results (Figures 5 and 6). Solid-state lithium-7 NMR
spectroscopy of both the phosphazene-containing and
phosphazene-free systems (18c, 19c, 20c) confirmed the
interaction of lithium cations with the oxygen units in
Exp er im en ta l Section
1. Gen er a l. Syntheses were carried out under an argon
atmosphere using standard Schlenk techniques or use of an
argon-filled glovebox (MBraun).
Solution-state NMR spectra were obtained at 298 K using
a Bruker AMX 360 NMR spectrometer resonating at 360.24
1
31
13
MHz for H, 145.81 MHz for P, and 90.56 MHz for C. For
1
13
H and C NMR spectra, the chemical shifts were referenced
31
3
to internal CDCl unless otherwise noted. For P spectra, the
chemical shifts were referenced to external 85% phosphoric
acid. Solid-state lithium-7 NMR experiments were obtained
using a Varian/Chemagnetics Infinity-500 NMR spectrometer
operated in quadrature mode at ambient temperature and
194.2 MHz. The quadrupole echo pulse sequence was used with
an echo delay of 30 µs, a relaxation delay of 60 s, a spectral
width of 1 MHz, and a π/2 pulse width of 2.55 µs. Gel
permeation chromatography results were obtained by means
of a Hewlett-Packard HP 1090 gel permeation chromatograph
equipped with two Phenomenex Phenogel linear 10µ columns
and a Hewlett-Packard 1047A refractive index detector cali-
brated vs monodisperse polystyrene standards. Elemental
analyses were obtained by Quantitative Technologies Inc.
Complex impedance analysis was performed in a constant-flow,
argon-atmosphere glovebox. The solid polymer electrolyte was
placed between two platinum electrodes and was supported
by a Teflon spacer. The platinum electrode-solid polymer
electrolyte sandwich was held in place in a Teflon fixture by
aluminum blocks. Leads were connected from the aluminum
blocks to a Hewlett-Packard 4192A LF impedance analyzer,
controlled by a desktop computer, and tested with an AC
frequency range of 5 Hz-13 MHz and an amplitude of 0.1 V.
Thermal data were obtained through differential scanning
calorimetry (DSC) using a Perkin-Elmer-7 thermal analysis
system equipped with a desktop computer. Polymer samples
7
backbone through broadening of the Li peaks.
Further examination of the solid polymer electrolytes
revealed some unique features. The conductivities in-
crease with increased amounts of salt for 16a -f and
1
7a -f due to the increased number of charge carriers
present in the system. However, the effect of increasing
salt concentration in SPEs (18b-f) comprised of the
longer ethyleneoxy containing polymer 13 is not as
distinct at lower temperatures but begins to display a
more profound effect at higher temperatures. These data
suggest that the extended length of the oligoethyleneoxy
chain of polymer 13 results in partial ionically cross-
linking of SPEs 18b-f at low temperatures and moder-
ate to high salt concentrations, which can be overcome
at high temperatures when more chain mobility is
imparted in the system. Phosphazene-free solid polymer
electrolytes 19a -f and 20a -f have significantly fewer
coordination sites. Therefore, ambient temperature
conductivities will be higher at lower salt loadings, but
the material will be ionically cross-linked at higher salt
concentrations. However, at increased temperatures the

Macromolecules, Vol. 36, No. 10, 2003
Novel Solid Polymer Electrolytes 3567
were heated from -100 to 50 °C under an atmosphere of dry
nitrogen. An approximately 30 mg sample was hermetically
sealed in aluminum pans and heated at rates of 10, 20, and
stirred overnight. Sodium 7-oxa-5-norbornene-2-methoxide
solution was added dropwise to the (NPCl ) solution at -78
2 3
°C. The mixture was then stirred and warmed slowly overnight
to ambient temperature. THF was removed by rotary evapora-
tion to leave a viscous oil. The oil was dissolved in diethyl ether
(500 mL) and was washed with water (3 × 250 mL). The
4
g
0 °C/min. The final T values were determined through
extrapolation to 0 °C/min heating rate. Mass spectra were
collected using a Micromass Quattro-II triple quadrupole mass
spectrometer.
4
diethyl ether layer was dried over MgSO and filtered. The
2
. Ma ter ia ls. Furan (99+%), methyl acrylate (99%), 5-nor-
solution was then concentrated, and the crude product was
sublimed (0.1 mmHg at 40 °C for 12 h) to leave the product
(5) as a viscous oil.
bornene-2-methanol (mixture of endo and exo isomers, 3b),
zinc iodide (98+%), sodium hydride (95%, 60% dispersion in
mineral oil), lithium aluminum hydride (95%), lithium bis-
trifluoromethylsulfonyl)imide (3M), [Cl
Strem), p-toluenesulfonyl chloride (98%), ethyl vinyl ether
99%), ethyl acetate, heptane, and methanol were used as
3 3 6
received. Hexachlorocyclotriphosphazene (N P Cl ) (Ethyl Corp./
Nippon Fine Chemical) was recrystallized from heptane and
sublimed at 0.2 mmHg at 30 °C before use. 2-Methoxyethanol
99%), 2-(2-methoxyethoxy)ethanol (99%), 2-(2-(2-methoxy-
1
For 5, H NMR: δ 0.68 (dd, 1H, endo), 1.22 (m, 1H, exo),
(
(
(
2
(PCy
3
)
2
RuCHPh]
1.39 (m, 1H, exo), 1.87-1.99 (br m, 2H, endo + exo), 2.55 (m,
1H, endo), 4.03 (m, 2H, exo), 4.16 (m, 2H, endo), 4.81 (s, 1H,
exo), 4.91 (m, 2H, endo + exo), 4.97 (m, 1H, endo), 6.24 (s, 2H,
exo), 6.33 (dd, 1H, endo), 6.38, (dd, 1H, endo). 13C NMR: δ
28.30, 28.90, 38.30, 71.97, 72.30, 78.50, 79.00, 79.30, 79.60,
3
1
132.4, 134.90, 137.00, 137.90. P NMR: δ 14.87 (td, 1 P), 22.89
+
(
(d, 2 P). MS ) m/e 438 (MH ).
ethoxy)ethoxy)ethanol (95%), dichloromethane, and diethyl
ether were distilled from calcium hydride prior to use. THF
was distilled from sodium benzophenone ketyl before use.
Solid polymer electrolytes 16a -f to 20a -f were prepared
by the dissolution of the polymer and the salt in anhydrous
THF, followed by slow evaporation of the solvent and subse-
quent vacuum-drying (40 °C at 0.1 mmHg) for 5 days. The solid
polymer electrolytes were then transferred to a glovebox under
an atmosphere of argon.
Preparation of [(7-oxa-5-norbornene-2-methoxy)pentakis(2-
methoxyethoxy)]cyclotriphosphazene (monomer 6). A 1 L flask
was charged with 95% sodium hydride (4.68 g, 0.185 mol) and
500 mL of THF. 2-Methoxyethanol (15 g, 0.185 mol) was added
dropwise to the sodium hydride suspension. The mixture was
stirred overnight. Compound 5 (13.5 g, 0.031 mol) was dis-
solved in 500 mL of THF in a 2 L flask. The sodium
2-methoxyethoxide solution was added dropwise to the solution
of 5 at -78 °C. The mixture was then stirred and warmed
slowly to room temperature overnight. The THF was then
removed by rotary evaporation, and the crude reaction mixture
was dissolved in ether and centrifuged. The ether was re-
moved, and the product was purified by column chromatog-
raphy (silica gel, 95:5 ethyl acetate: methanol). The solvent
was removed, and the residue was dried overnight (room
temperature 0.1 mmHg) to leave 10.0 g (51%) of viscous oil
(6).
3
. P r ep a r a tion of Cyclotr ip h osp h a zen e-F u n ction a l-
ized Mon om er s. (a) Route A. Preparation of [(7-oxa-5-
norbornene-2-methoxy)pentakis(2-(2-methoxyethoxy)ethoxy)]-
cyclotriphosphazene, 7. A solution of 2-(2-methoxyethoxy)ethanol
(22.4 g, 0.1864 mol) in 50 mL of THF was added dropwise to
a suspension of sodium hydride (8.28 g, 0.207 mol) in 350 mL
of THF. The reaction mixture was stirred under argon at room
temperature for 10 h and was added to a solution of hexachlo-
rocyclotriphosphazene (12.00 g, 0.0345 mol) in 300 mL of THF
at 0 °C. The reaction mixture was allowed to warm to room
temperature with continued stirring for 12 h. The resultant
suspension was centrifuged to remove sodium chloride, and
the remaining solution was decanted and concentrated under
reduced pressure to yield 25.2 g (95%) of an oil containing 54%
pentakis[(2-(2-methoxyethoxy)ethoxy)(monochloro)]cyclo-
1
For 6, H NMR: δ 0.59 (dd, 1H, endo), 1.18 (m, 1H, exo),
1.30 (m, 1H, exo), 1.77-1.91 (m, 2H, endo + exo), 2.45 (m, 1H,
endo), 3.21 (s, 15H), 3.35 (m, 2H, exo), 3.45 (m, 10H), 3.61 (m,
2H, endo), 3.87 (m, 10H), 4.73 (s, 1H, exo), 4.76 (m, 2H, endo
+ exo), 4.87 (d,1H, endo), 6.14 (s, 2H, exo), 6.26 (dd, 1H, endo),
6.31 (dd, 1H, endo). 13C NMR: δ 28.10, 28.60, 38.50, 38.80,
57.09, 59.30, 61.40, 65.30, 67.40, 68.50, 68.70, 71.70, 78.10,
3
1
31
triphosphazene ( P NMR (D
2
O): δ 27.8 (t, 1P), 15.61 (d, 2P))
78.70, 79.40, 79.80, 132.90, 135.10, 136.4. P NMR: δ 18.20
+
and 46% hexakis[(2-(2-methoxyethoxy)ethoxy)]cyclotriphos-
phazene ( P NMR (D
without further purification. A solution of this oil (19.82 g,
(m, 3 P). MS ) m/e 636 (MH ). Elemental analysis: calcd %
3
1
2
O): δ 18.99 (s, 3P)) which was used
C, 41.60; % H, 7.00; % N, 6.60; % P, 14.60. Found: % C, 41.50;
% H, 7.20; % N, 6.60; % P, 14.90.
0
7
.0259 mol) in 200 mL of THF was treated with potassium
-oxa-5-norbornene-2-methoxide, itself synthesized via the
Preparation of [(7-oxa-5-norbornene-2-methoxy)pentakis(2-
(2-(2-methoxyethoxy)ethoxy)ethoxy)]cyclotriphosphazene, (mono-
mer 8). The procedure to prepare monomer 8 was the same
as for monomer 6. The quantities used are as follows: 95%
sodium hydride (3.88 g, 0.162 mol) and 200 mL of THF, 2-(2-
(2-methoxyethoxy)ethoxy)ethanol (26.00 g, 0.158 mol), 5 (11.2
g, 0.026 mol), and 100 mL of THF. The product was purfied
through column chromatography (silica gel, 85:15 ethyl ac-
etate:methanol) to afford 10.1 g (37%) of monomer 8.
reaction of 7-oxa-5-norbornene-2-methanol (3.59 g, 0.0285 mol)
with potassium tert-butoxide (4.36 g, 0.0388 mol) in 200 mL
of THF. The solution was stirred for 24 h at room temperature,
concentrated under reduced pressure, and purified by column
chromatography (silica gel, 85:15 ethyl acetate:methanol) to
afford 7.2 g (65% based on pentakis[(2-(2-methoxyethoxy)-
ethoxy)(monochloro)]cyclotriphosphazene) of colorless oil, 7.
1
1
For 7, H NMR: δ 0.77 (dd,1H, endo), 1.22 (m, 1H, exo),
For 8, H NMR: δ 0.55 (dd, 1H, endo), 1.03 (m, 1H, exo),
1
.34 (m, 1H, exo), 1.75 (m, 1H, exo), 1.95 (m, 1H, endo), 2.42
1.19 (m, 1H, exo), 1.74-1.89 (br m, 2H, exo + endo), 2.36 (m,
1H, endo), 3.16 (s, 15H), 3.26 (m, 2H, exo), 3.35 (m, 10H), 3.45
(m, 40H), 3.61 (m, 2H, endo), 3.79 (m, 10H), 4.66 (s, 1H, exo),
4.69 (m, 2H, endo + exo), 4.81 (d, 1H, endo), 6.13 (s, 2H, exo),
6.17 (dd, 1H, endo), 6.28 (dd, 1H, endo). 13C NMR: δ 27.60,
28.20, 38.10, 38.30, 50.20, 58.80, 64.90, 68.00, 68.30, 69.80,
70.40, 71.80, 73.90, 78.20, 78.80, 79.20, 132.30, 134.60, 135.90,
(m, 1H, endo), 3.33 (m, 2H, exo), 3.46 (s, 15H), 3.55 (m, 2H,
endo), 3.62 (m, 10H), 3.73 (m, 10H), 3.78 (m, 10H), 4.17 (m,
1
5
0H), 4.91 (m,1H, endo), 4.93 (m,1H, exo), 4.98 (m,1H, exo),
.03 (m, 1H, exo), 6.35 (dd, 1H, endo), 6.40 (s, 2H, exo), 6.45
1
3
(dd, 1H, endo). C NMR: δ 26.49, 27.05, 36.90, 37.2, 57.72,
6
1
8
%
7
3.80, 67.14, 66.91, 68.80, 69.27, 70.46, 75.62, 75.97, 76.49,
3
1
31
+
31.25, 133.48, 134.75. P NMR: δ 18.1 (m, 3P). MS ) m/e
136.30. P NMR: δ 17.90 (m, 3 P). MS ) m/e 1077 (MH ).
Elemental analysis: calcd % C, 46.91; % H, 7.92; % N, 3.95;
% P, 8.62. Found: % C, 47.11; % H, 8.11; % N, 3.91; % P, 8.67.
4. P r ep a r a tion of Oligoeth ylen eoxy-F u n ction a lized
Nor bor n en e a n d 7-Oxa n or bor n en e Mon om er s. Prepara-
tion of 5-[2-(2-methoxyethoxy)ethoxymethyl]-7-oxanorbornene
(monomer 9). 7-Oxa-5-norbornene-2-methanol (3a ) (10.0 g,
0.0793 mol) was added slowly to a suspension of NaH (95%)
(2.00 g, 0.0793 mol) in 165 mL of THF. After the mixture was
stirred at room temperature for 10 h, it was cooled to -78 °C,
and to the mixture was added 2-(2-methoxyethoxy)ethyl p-
toluenesulfonate (22.83 g, 0.0832 mol). Following the complete
+
56 (MH ). Elemental analysis: calcd % C, 44.91; % H, 7.54;
N, 4.91; % O, 31.78; % P, 10.86. Found: % C, 43.59; % H,
.68; % N, 4.96; % P, 10.38.
. P r ep a r a tion of Cyclotr ip h osp h a zen e-F u n ction a l-
3
ized Mon om er s. (b) Route B. Preparation of pentachlo-
romono(7-oxa-5-norbornene-2-methoxy)cyclotriphosphazene, 5.
Hexachlorocyclotriphosphazene (NPCl ) (30 g, 0.863 mol) was
2 3
dissolved in 300 mL of THF in a 2 L flask. A 1 L flask was
charged with 95% sodium hydride (1.57 g, 0.052 mol) and 200
mL of THF. 7-Oxa-5-norbornene-2-methanol (3a ) (6.53 g, 0.062
mol) was added dropwise to a sodium hydride suspension and

3
568 Allcock et al.
Macromolecules, Vol. 36, No. 10, 2003
addition of 2-(2-methoxyethoxy)ethyl p-toluenesulfonate the
reaction mixture was warmed to room temperature and stirred
for 12 h. The resultant suspension was filtered and washed
with ethyl acetate, and the remaining ethyl acetate solution
was extracted with deionized water. The ethyl acetate layer
132 000, M
w
) 172 000, PDI ) 1.3. Elemental analysis: calcd
% C, 44.91; % H, 7.54; % N, 4.91; % P, 10.86. Found: % C,
44.95; % H, 7.66; % N, 4.70; % P, 10.85.
Preparation of polymer 13. Polymer 13 was prepared in a
manner similar to polymer 11 using monomer 8 (3.97 g, 3.7
was collected, dried over MgSO
4
, filtered, and concentrated
2 3 2
mmol) in 8 mL of dichloromethane and a solution of [Cl (PCy ) -
under reduced pressure to yield an oil which was further
purified through column chromatography (silica gel, 90:10
EtOAc:hexanes) to afford 9.9 g (55%) of colorless oil (9)
RuCHPh] (0.011 g, 0.01 mmol) in 1 mL of dichloromethane.
After purification by dialysis, the solvent was removed under
reduced pressure to yield 2.2 g (51%) of polymer 13.
1
(
mixture of endo and exo isomers).
For 9, H NMR: δ 0.66 (dd, 1H, endo), 1.20 (m, 1H, exo),
.35 (m, 1H, exo), 1.75 (m, 1H, exo), 1.89 (m, 1H, endo), 2.35
For 13, H NMR: δ 1.82-2.5 (br m, 3H), 3.30 (s, 17H), 3.33
1
(m, 10H), 3.36-3.45 (br m, 40H), 3.89 (br s, 10H), 4.15 (br m,
1H), 4.55 (br m, 1H), 5.42-5.67 (br m, 2H). 13C NMR: δ 25.50,
1
3
1
(
3
m, 1H, endo), 3.29-3.35 (m, 4H, endo + exo), 3.51 (s, 3H),
29.60, 30.8, 58.90, 65.10, 67.90, 70.00, 70.5, 71.8, 132.3.
P
.53-3.63 (br m, 8H), 4.84 (s, 1H, exo), 4.90 (d, 2H, exo +
NMR: δ 18.1 (m, 3 P); Mn ) 132 000, Mw ) 168 000, PDI )
1.27. Elemental analysis: calcd % C, 46.91; % H, 7.93; % N,
3.94; % P, 8.63. Found: % C, 47.12; % H, 8.03; % N, 3.87; % P,
8.56.
endo), 4.97 (d, 1H, endo), 6.23 (dd, 1H, endo), 6.30 (s, 2H, exo),
6
5
7
2
.35 (dd, 1H, endo). 13C NMR: δ 26.39, 26.51, 36.29, 36.38,
7.43, 68.82, 68.86, 68.95, 68.98, 70.42, 72.26, 72.61, 75.63,
5,99, 76.20, 76.70, 78.1, 130.92, 133.42, 134.23. MS ) m/e
Preparation of polymer 14. Under inert atmosphere, a
solution of [Cl (PCy ) RuCHPh] (0.047 g, 0.057 mmol) in 5 mL
+
28 (M ). Elemental analysis: calcd % C, 63.14; % H, 8.83; %
2
3 2
O, 28.03. Found: % C, 62.51; % H, 8.68; % O, 28.56.
of dichloromethane was added to a solution degassed monomer
9 (3.6 g, 0.0158 mol) in 14 mL of dichloromethane. After
addition of the catalyst, the solution became increasingly
viscous, and the polymerization was continued for 10 h at room
temperature, at which time 0.5 mL of ethyl vinyl ether was
added to the reaction mixture. The polymer solution was then
precipitated into hexanes to yield a rubbery polymer. This was
further purified by precipitations into hexane and pentane and
was dried under vacuum to yield 2.5 g (69%) of polymer 14.
Preparation of 5-[2-(2-methoxyethoxy)ethoxymethyl]nor-
bornene (monomer 10). Monomer 10 was synthesized in a
manner similar to monomer 9. 5-Norbornene-2-methanol, 3b
(
(
10.0 g, 0.0805 mol), was added slowly to a suspension of NaH
95%) (2.03 g, 0.0805 mol) in 165 mL of THF. After being
stirred at room temperature for 10 h the reaction mixture was
cooled to -78 °C, and to the mixture was added 2-(2-
methoxyethoxy)ethyl p-toluenesulfonate (23.19 g, 0.0846 mol).
Following the addition the reaction mixture was allowed to
warm to room temperature and stirred for 12 h. The resultant
suspension was filtered and washed with diethyl ether, and
the remaining diethyl ether solution was extracted with
deionized water. The diethyl ether layer was collected, dried
1
For 14, H NMR: δ 1.65-2.41 (br m, 3H), 3.38 (s, 5H), 3.54-
3.63 (br m, 8H), 4.36 (br m, 1H), 4.69 (br m, 1H), 5.53 (br s,
1H), 5.72 (br s, 1H). 13C NMR: δ 36.81, 37.24, 44.82, 46.41,
46.59, 47.01, 59.42, 71.21, 71.99, 72.73, 75.12, 78.15, 79.35,
82.75, 133.54, 133.32. Mn ) 109 000, Mw ) 300 000, PDI )
2.8. Elemental analysis: calcd % C, 63.14; % H, 8.83; % O,
28.03. Found: % C, 63.10; % H, 8.68; % O, 28.27.
4
over MgSO , filtered, and concentrated under reduced pressure
to yield a dark oil which was further purified through column
chromatography (silica gel, 80:20 hexanes:ethyl acetate) to
afford 9.0 g (50%) of colorless oil, 10 (mixture of endo and exo
isomers).
Preparation of polymer 15. Polymer 15 was prepared in a
manner similar to polymer 14 using monomer 10 (4.0 g, 0.0177
mol) in 15 mL of dichloromethane and a solution of [Cl (PCy ) -
2
3 2
1
For 10, H NMR: δ 0.55 (dd, 1H), 1.05-1.45 (m, 4H), 1.5-
RuCHPh] (0.0529 g, 0.064 mmol) in 5 mL of dichloromethane.
Polymer 15 was purified through precipitations into methanol/
water and hexanes to yield 3.0 g (60%) of polymer 15.
1
3
.9 (m, 2H), 2.30 (m, 1H), 2.70-2.91 (br m, 2H), 3.38 (s, 3H),
.55 (m, 4H), 3.65 (m, 6H), 5.92 (dd, 1H), 6.11 (dd, 1H). 13
C
NMR: δ 29.15, 29.70, 38.71, 38.79, 41.53, 42.19, 43.64, 43.95,
1
For 15, H NMR: δ 0.86 (br m, 1H), 1.54 (br m, 1H), 1.17
br m, 1H), 1.85 (br m, 1H), 2.20 (br m, 1H), 2.73 (br m, 1H),
4
7
4.99, 49.40, 59.02, 70.26, 70.29, 70.56, 70.63, 72.00, 75.07,
6.05, 132.48, 136.62, 137.06. MS ) m/e 226 (M ). Elemental
(
+
2
4
3
7
)
%
.93 (br m, 1H), 3.34 (br s, 5H), 3.51 (br m, 4H), 3.59 (br m,
H), 5.48 (br m, 2H). C NMR: δ 29.81, 36.50, 37.34, 39.20,
9.91, 41.65, 42.53, 44.59, 46.50, 59.18, 70.49, 70.67, 72.12,
analysis: calcd % C, 68.99; % H, 9.80; % O, 21.21. Found: %
C, 67.90; % H, 9.69; % O, 22.29.
13
5
. Gen er a l P r ep a r a tion of P olym er s. Preparation of
3.54, 74.84, 129.99, 131.25, 133.26, 134.59. M
107 000, PDI ) 1.1 Elemental analysis: calcd % C, 68.99;
H, 9.80; % O, 21.21. Found: % C, 68.87; % H, 9.90; % O,
n
) 94 000, M
w
polymer 11. Monomer 6 (5 g, 8 mmol) was degassed under
vacuum in 50 mL three-neck flask and then dissolved in 25
mL of anhydrous dichloromethane. The initiator [Cl (PCy ) -
2 3 2
2
1.60.
RuCHPh] (0.026 g, 0.03 mmol) in 1 mL of dichloromethane
was added to the monomer quickly. The solution was stirred
overnight, and then 0.5 mL of ethyl vinyl ether was added to
terminate the reaction. The polymer solution was dialyzed
against THF, 50:50 THF:methanol, and methanol. The solvent
was removed to yield 2.6 g (52%) of a rubbery gum.
Ack n ow led gm en t. We thank the National Science
Foundation for support of this work through Grant
CHE-0211638, and Dr. Alan Benesi for performing the
7
solid-state Li NMR experiments.
1
For 11, H NMR: δ 1.81-2.45 (br m, 3H), 3.31 (br s, 17H),
Refer en ces a n d Notes
3
1
4
1
3
.52 (br s, 10H), 3.99 (br s, 10H), 4.26 (br m, 1H), 4.65 (br m,
H), 5.50 (br s, 1H), 5.56 (br s, 1H). 13C NMR: δ 29.70, 35.80,
5.80, 46.50, 56.80, 59.00, 61.20, 65.00, 65.90, 71.40, 74.4, 81.3,
(
1) Gray, F. M. Polymer Electrolytes; The Royal Society of
Chemistry: Cambridge, 1997.
2) Dell, R.; Rand, D. J . Power Sources 2001, 100, 2-17.
3) Vincent, C. Solid State Ionics 2000, 134, 159-167.
(4) Dell, R. Solid State Ionics 2000, 134, 139-158.
(5) Yoda, S.; Ishihara, K. J . Power Sources 1997, 68, 3-7.
(6) Dias, F.; Plomp, L.; Veldhuis, J . J . Power Sources 2000, 88,
169-181.
7) Owen, J . Chem. Soc. Rev. 1997, 26, 259-267.
8) Broussely, M.; Brensan, P.; Simon, B. Electrochim. Acta 1999,
3
1
32.90. P NMR: δ 18.20 (s, 3 P); M
n
) 176 977, M
w
)
(
(
94 718, PDI ) 2.23. Elemental analysis: calcd % C, 41.61; %
H, 7.03; % N, 6.62; % P, 14.62. Found: % C, 41.72; % H, 6.97;
%
N, 6.54; % P, 14.74.
Preparation of polymer 12. Polymer 12 was prepared in a
manner similar to polymer 11 using monomer 7 (5.0 g, 0.0058
3 2
mol) in 5 mL of dichloromethane and a solution of [Cl (PCy ) -
(
(
2
RuCHPh] (0.017 g, 0.0212 mmol) in 1 mL of dichloromethane.
After purification by dialysis, the solvent was removed under
reduced pressure to yield 3.5 g (70%) of polymer 12.
4
5, 3-22.
(
9) Whittingham, M. S. Solid State Ionics 2000, 134, 169-178.
(
(
10) Fenton, D.; Parker, J .; Wright, P. Polymer 1973, 14, 589.
11) Armand, M.; Chabagno, J .; Ducolt, M. Abstracts of Papers,
Second International Meeting on Solid Electrolytes, St.
Andrews, Scotland, 1978; p 65.
1
For 12, H NMR: δ 1.77-2.41 (br m, 3H), 3.32 (s, 17H),
3
4
3
7
.48 (m, 10H), 3.55 (m, 20H), 4.02 (m, 10H), 4.25 (br m, 1H),
1
3
.62 (br m, 1H), 5.42 (br s, 1H), 5.67 (br s, 1H). C NMR: δ
5.83, 45.83, 46.55, 59.12, 65.17, 65.95, 70.17, 70.65, 72.07,
(12) Blonsky, P.; Shriver, D.; Austin, P.; Allcock, H. R. J . Am.
4.36, 81.29, 133.22, 133.51. 31P NMR: δ 18.12 (s, 3P); M
)
Chem. Soc. 1984, 106, 6854-6855.
n

Macromolecules, Vol. 36, No. 10, 2003
Novel Solid Polymer Electrolytes 3569
(
(
(
(
(
(
(
13) Allcock, H. R.; Napierala, M. E.; Cameron, C. G.; O’Connor,
(23) Ivin, K.; Mol, J . Olefin Metathesis and Metathesis Polymer-
ization; Academic Press: New York, 1997.
(24) Bhowmick, A.; Stein, C.; Stephens, H. Chapter in: Handbook
of Elastomers; Bhowmick, A., Stephens, H., Eds.; Marcel
Dekker: New York, 2001.
S. J . M. Macromolecules 1996, 29, 1951-1956.
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M. E.; Cameron, C. G. Macromolecules 1996, 29, 7544-7552.
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ecules 1998, 31, 753-759.
(25) Draxler, A. Chapter in: Handbook of Elastomers; Bhowmick,
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M. Macromolecules 1998, 31, 8026-8035.
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A., Stephens, H., Eds.; Marcel Dekker: New York, 2001.
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1992, 25, 5893-5900.
8
036-8046.
(
27) Novak, B. M.; Grubbs, R. H. J . Am. Chem. Soc. 1988, 110,
18) Allcock, H. R.; Laredo, W. L.; Kellam, E. C., III; Morford, R.
V. Macromolecules 2001, 34, 787-794.
960-961.
(28) Brion, F. Tetrahedron Lett. 1982, 23, 5299-5302.
19) Allcock, H. R.; Laredo, W. R.; Morford, R. V. Solid State Ionics
(
29) Kotsuki, H.; Ohnishi, H.; Akitomo, Y.; Ochi, M. Bull. Chem.
2
001, 139, 27-36.
Soc. J pn. 1986, 59, 3881-3884.
(
(
20) Inoue, K.; Itaya, T. Bull. Chem. Soc. J pn. 2001, 74, 1-10.
21) Allcock, H. R. Chemistry and Applications of Polyphos-
phazenes; Wiley-Interscience: Hoboken, NJ , 2003.
(
30) Cummins, C.; Schrock, R.; Cohen, R. Chem. Mater. 1992, 4,
2
7-30.
(31) Ratner, R.; Shriver, D. Chem. Rev. 1988, 88, 109-124.
(22) Mark, J . E.; Allcock, H. R.; West, R. Chapter 3in: Inorganic
Polymers; Prentice-Hall: Englewood Cliffs, NJ , 1992.
MA0217478