Controlled molecular design of ether- and ester-bridged norbornenes and their ring-opening metathesis polymerizations

Article abstract of DOI:10.1139/v99-164

A series of functionalized polynorbornenes containing pendent ether- or ester-bridged poly(aromatic ether) chains were prepared. The ether-bridged norbornene complex was synthesized via cyclopentadienyliron-mediated nucleophilic aromatic substitution reactions. This methodology, combined with that of dicyclohexylcarbodiimidemediated coupling, allowed for the formation of novel oligomeric aryl ether and ester substituted norbornene complexes. Photolytic demetallation gave the monomers in good yields. Structural identification of the exo and endo isomers of both the metallated and demetallated norbornene derivatives was accomplished using HH and CH COSY NMR techniques. Ring-opening metathesis polymerization (ROMP) of these monomers using RuCl₃(hydrate) and (Cy₃P)₂Cl₂Ru=CHPh allowed for the preparation of the functionalized polynorbornenes. Thermal analysis of the resulting polymeric materials demonstrated greater thermal stability as the number of aryl ether groups increased.

Full text of DOI:10.1139/v99-164

1797
Controlled molecular design of ether- and ester-
bridged norbornenes and their ring-opening
metathesis polymerizations
Alaa S. Abd-El-Aziz, Andrea L. Edel, Leslie J. May, Karen M. Epp,
and Harold M. Hutton
Abstract: A series of functionalized polynorbornenes containing pendent ether- or ester-bridged poly(aromatic ether)
chains were prepared. The ether-bridged norbornene complex was synthesized via cyclopentadienyliron-mediated
nucleophilic aromatic substitution reactions. This methodology, combined with that of dicyclohexylcarbodiimide-
mediated coupling, allowed for the formation of novel oligomeric aryl ether and ester substituted norbornene
complexes. Photolytic demetallation gave the monomers in good yields. Structural identification of the exo and endo
isomers of both the metallated and demetallated norbornene derivatives was accomplished using HH and CH COSY
NMR techniques. Ring-opening metathesis polymerization (ROMP) of these monomers using RuCl3(hydrate) and
(Cy3P)2Cl2Ru=CHPh allowed for the preparation of the functionalized polynorbornenes. Thermal analysis of the
resulting polymeric materials demonstrated greater thermal stability as the number of aryl ether groups increased.
Key words: aromatic ethers, cyclopentadienyliron, polynorbornene, ROMP, ruthenium catalysts.
Résumé : On a préparé une série de polynorbornènes fonctionnalisés comportant des chaînes pendantes (latérales)
poly(éthers aromatiques) à pont éther ou ester. On a synthétisé le complexe du norbornène à pont éther par le biais de
réactions de substitutions aromatiques nucléophiliques catalysées par le cyclopendiénylfer. Cette méthodologie,
combinée à celle du couplage catalysé par le dicyclohexylcarbodiimide, permet de former de nouveaux complexes
oligomères du norbornène substitué par des esters ou des éthers aromatiques. La démétallation photolytique conduit aux
monomères avec des bons rendements. On a déterminé la structure des isomères tant exo qu’endo des dérivés
norbornènes métallés et démétallés en faisant appel aux techniques RMN « COSY » HH et CH. En soumettant ces
monomères à une réaction de polymérisation par ouverture de cycle accompagnée d’une métathèse à l’aide de
RuCl3(hydrate) et de (Cy3P)2Cl2Ru=CHPh, permet de préparer des polynorborbènes fonctionnalisés. Une analyse
thermique des matériaux polymériques qui en résultent a permis de démontrer que la stabilité thermique augmente avec
une augmentation du nombre de groupes éthers aromatiques.
Mots clés : éthers aromatiques, cyclopentadiénylfer, polynorbornène, « ROMP », catalyseurs de ruthénium.
[Traduit par la Rédaction] Abd-El-Aziz et al. 1809
Introduction
dent aryl ether chains bridged to the norbornene unit either
through an ether or ester linkage.
Ring-opening metathesis polymerization (ROMP) of
highly strained bicyclo[2.2.1]heptenes using classical initia-
tors has been well established in the literature (1–5). A
drawback of these initiators is their low tolerance for mono-
mers containing polar functional groups, which results in ap-
preciable catalyst deactivation during polymerization (5).
However, recent developments in ROMP catalysts have al-
lowed for the incorporation of polar functionalities such as
chloro, fluoro, hydroxyl, nitrile, ester, and imide groups into
the norbornene unit (15–24). Two classes of catalytic sys-
tems have been developed and adopted as the primary cata-
Polynorbornene, first prepared in the early 1960’s by
Truett et al. (1), has seen numerous applications in industry
due its high tear strength and dynamic-damping properties
(2–5). As the demand for higher temperature applications
has increased, there have been attempts to modify poly-
norbornene via functionalization of the polymer backbone
(6–9). Poly(aromatic ethers) are of particular importance due
to their high thermal stability (10–14). In addition, ester de-
rivatives of polynorbornene warrant investigation due to
their potential as thermoplastic resins (2, 3). It has therefore
been of interest to functionalize polynorbornene with pen-
Received April 29, 1999.
This paper is dedicated to Professor Ted Schaefer in recognition of his outstanding contributions to Canadian chemistry.
A.S. Abd-El-Aziz,1 A.L. Edel, L.J. May, K.M. Epp, and H.M. Hutton. Department of Chemistry, University of Winnipeg,
Winnipeg, MB R3B 2E9, Canada.
1Author to whom correspondence may be addressed. Telephone: (204) 786-9335. Fax: (204) 775-2114.
e-mail: abdelaziz@uwinnipeg.ca
Can. J. Chem. 77: 1797–1809 (1999)
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Can. J. Chem. Vol. 77, 1999
Scheme 1.
lysts used in the ROMP of polar norbornene monomers.
These include ruthenium carbene complexes (9, 25–39) as
well as molybdenum and tungsten alkylidene complexes
(6–8, 17, 18, 21, 23, 40–50). Ruthenium-based systems have
found greater industrial application due to their ability to fa-
cilitate ROMP in the presence of oxygen and protic environ-
ments, as well as their increased tolerance towards a large
variety of polar functional groups. Recently, Grubbs and co-
workers (29) developed a highly reactive ruthenium-based
benzylidene catalyst, which allows for the living ring-opening
metathesis polymerization of a variety of functionalized
norbornene monomers in both organic and aqueous solvents.
This catalyst, known as bis(tricyclohexylphosphine)benzylidene
ruthenium(IV) dichloride or “Grubbs’ catalyst,” has proven
to be extremely effective in the ROMP of highly strained
bicyclic olefins (29, 30, 32, 39).
Our success in the preparation of poly(aromatic ethers)
via cyclopentadienyliron (CpFe+)-mediated nucleophilic aro-
matic substitution reactions (51–58) has prompted our inves-
tigation into the controlled molecular design of norbornene
monomers containing pendent aryl ether and (or) ester
chains. Recently, we communicated our initial results of the
cyclopentadienyliron-complexed norbornenes and their sub-
sequent polymerizations (59). Here, we report the full syn-
thesis and characterization of these substituted norbornene
monomers, as well as their ROMP using either RuCl3(hy-
drate) or (Cy3P)2Cl2Ru=CHPh catalysts.
first containing an ether bridge between the norbornene unit
and the aromatic ether side chain, and the second containing
an ester bridge.
Preparation of the etheric linked monomer was readily
performed via SNAr of the chloroarene complex (1) with an
excess of exo,endo-5-norbornene-2-methanol (2), as shown
in Scheme 1. Generation of the nucleophile under an inert
nitrogen atmosphere for 1 h, followed by the addition of η6-
chlorobenzene-η5-cyclopentadienyliron hexafluorophosphate
(1) dissolved in a mixture of N,N-dimethylformamide
(DMF) and THF yielded the product (3) in 85% yield after
reacting for 16 h at room temperature.
Preparation of the ester-bridged complexes was accom-
plished via the condensation reaction of 5-norbornene-2-
methanol (2) with the benzoic acid complexes as described
in Scheme 2. (Benzoic acid)CpFe+ (5) and (p-chlorobenzoic
acid)CpFe+ (6) were prepared using the methodology estab-
lished by Nesmeyanov et al. (61). Condensation of these
acid complexes with 2 in the presence of dicyclohexylcar-
bodiimide (DCC) and pyridine in dichloromethane afforded
the ester-functionalized norbornene complexes 7 and 8, in 62
and 70% yields, respectively.
This methodology was further extended towards the prep-
aration of norbornene complexes containing two or three
pendent metal moieties within the aryl ether chain. The syn-
thesis of these aryl ether derivatives involved the initial prep-
aration of the terminal phenoxy complexes (14, 15), as
detailed in Scheme 3. This was accomplished by reacting the
bimetallic arene complex (12), for example, with an excess
of hydroquinone (13) in a THF–DMF solvent mixture for
16 h. The resulting yellow precipitate was isolated in 90%
yield for complex 15. Characterization of the bimetallic
complex (15) was readily accomplished using 1H NMR
spectroscopy. The two Cp resonances, appearing as distinct
singlets at 5.31 and 5.25 ppm, indicated successful prepara-
tion of the desired product. Further verification resulted from
the analysis of the 13C NMR spectrum, which also showed
two Cp resonances at 78.80 and 78.13 ppm.
Results and discussion
Monomer syntheses
Norbornene monomers containing ether and (or) ester
bridges were synthesized using metal-mediated nucleophilic
aromatic substitution (SNAr). This methodology was used to
prepare poly(aromatic ether) chains pendent to norbornene
monomers, which would otherwise be difficult to prepare us-
ing traditional organic methods (60). This report details the
synthesis of two new classes of norbornene monomers, the
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Abd-El-Aziz et al.
1799
Scheme 2.
Scheme 3.
Nucleophilic aromatic substitution was used to prepare the
bi- (16) and tri-metallic (17) norbornene complexes. This
was done by reacting a 1:1 molar ratio of complex 14 or 15
with 8 in the presence of excess base in DMF, as described
in Scheme 4. The resulting yellow precipitates were consis-
tently isolated in high yields ranging from 81–86%. Confir-
mation of the structure of the trimetallic complex (17) was
obtained using one-dimensional NMR techniques. Three Cp
resonances in the 1H NMR spectrum appearing at 5.34, 5.32,
and 5.26 ppm and in the 13C NMR at 79.60, 78.97, and
78.08 ppm were consistent with the proposed structure.
Isolation of the organic monomers from their cyclopenta-
dienyliron moieties was achieved via photolytic demetal-
lation (62). Complexes 3, 7, 8, 16, and 17 were each
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Can. J. Chem. Vol. 77, 1999
1
Scheme 4.
Fig. 1. H and 13C NMR spectra of complex 8.
nuclear correlation spectroscopy (CH COSY) was used to
locate the 13C NMR chemical shifts.
Cyclopentadienyl resonances, which appear from 5.4 to
1
5.0 ppm in the H NMR spectra and from 82 to 78 ppm in
the 13C NMR spectra, were instrumental in confirming the
structure of the complexed norbornenes 3, 7, 8, 16, and 17.
Complex 3 showed a strong singlet at 5.14 ppm and at
1
77.06 ppm in the H NMR and 13C NMR spectra, respec-
tively, representative of the cyclopentadienyl resonance. In
the ester-bridged derivatives, the Cp resonance was identi-
fied further downfield than in the ether-bridged complex due
to the stronger electron-withdrawing capability of the car-
bonyl group. Therefore, the Cp resonance in complex 8 ap-
peared as a single peak at 5.36 ppm and at 81.47 ppm in the
1H and 13C NMR spectra, respectively (Fig. 1). The appear-
ance of only one Cp signal for the two isomers in both of
these complexes was attributed to the large separation be-
tween the norbornene unit and the Cp ring. This distance
provided sufficient spacing between the two groups such that
the electronic effects of the exo, endo isomerism at C-2 did
not influence the Cp protons. Although only one Cp was
present for these complexes, evidence for the presence of
two isomers was observed with respect to the number of
methylene protons (norbornene–CH2O) and vinyl protons.
With respect to the methylene protons, four resonances at
4.20 and 4.03 ppm and at 4.53 and 4.36 ppm in 8 for the
dissolved in a 1:4 ratio of acetonitrile to dichloromethane,
followed by irradiation under a xenon lamp for 4–8 h, the
length of time increasing as the number of CpFe+ moieties
increased. The organic monomers 4, 9, 10, 18, and 19, were
isolated by this process in good yields.
Monomer characterization
Structural analysis of the functionalized norbornene mole-
cules (3, 4, 7–10, 16–19) was accomplished using NMR, IR,
C-H analysis and MS. One- and two-dimensional NMR
spectroscopic techniques were extremely valuable in the
characterization process due to the complicated exo, endo
isomeric mixture of the products. As the 1-D NMR spectra
were quite complex, homonuclear correlation spectroscopy
(HH COSY) was employed as a means to identify proton–
proton connectivities and chemical shifts. Once all of the
protons were assigned to the exo or endo isomers, hetero-
© 1999 NRC Canada

Abd-El-Aziz et al.
1801
Fig. 2. HH COSY NMR of complex 8 showing relevant connectivities for exo and endo isomer determination.
endo and exo isomers, respectively, were observed. The vi-
nyl protons at 6.21 and 6.05 ppm for the endo H5 and H6
protons and at 6.14 and 6.10 ppm for the exo H5 and H6 pro-
tons, as described in Fig. 1.
3x) than between two endo protons (H-2 and H-3n) despite
identical dihedral angles. This allowed for further distinction
between the exo and endo isomers. Once these well-defined
couplings were located, the rest of the protons could be
identified based upon their connectivities as determined by
the HH COSY spectrum.
Previous
NMR
studies
involving
substituted
bicyclo[2.2.1]heptenes have detailed the identification of the
exo and endo isomers relative to several key couplings lo-
cated for certain proton resonances (63–70). These corre-
spond to the H-1, H-2, H-3x, and H-3n protons, as identified
in Fig. 2. Location of the endo isomer was assigned based
upon the coupling between the exo H-2 and the bridgehead
H-1 protons and (or) for the exo H-3x proton to the bridge-
head H-4 proton, showing moderate intensity in their con-
tours. Although these couplings could not be measured due
to peak broadness, their connectivities were observed in the
HH COSY NMR spectrum, as shown in Fig. 2 for complex
8. Literature values for this particular coupling report J val-
ues in the range of 3.2–3.9 Hz, which verifies the modest
coupling for these protons (67). As for the exo isomer, no
coupling or connectivity was observed for the endo H-2 pro-
ton to H-1, or for the endo H-3n proton to H-4. This obser-
vation is in agreement with previous investigations of the
endo H-2 and H-3n resonances in exo substituted norbornene
derivatives (67). Strong coupling between the two exo pro-
tons H-2 and H-3x was identified in the HH COSY, indicat-
ing the presence of the endo isomer. Complex 8 had a
calculated J value of 8.9 Hz for this coupling, which is also
shown in the HH COSY spectrum. Musher (65) has reported
more intense coupling between two exo protons (H-2 and H-
Photolytic demetallation of complexes 3, 7, 8, 16, and 17
led to the isolation of the substituted norbornene monomers
4, 9, 10, 18, and 19 in good yields. NMR, IR, C-H analysis,
and MS techniques were used to confirm the structures of
1
the demetallated products. In the H NMR spectrum of com-
pound 4, as an example, the absence of the Cp resonance at
5.14 ppm observed in complex 3 indicated the loss of the
metallic moiety. Further evidence for the liberation of the or-
ganic monomer was observed in the upfield shift of the
methylene resonances (norbornene–CH2O) from 4.38 to
3.87 ppm in 3 to 4.05–3.57 ppm in 4. A downfield shift of
the aromatic protons from their original positions at 6.40–
6.30 and 6.20–6.16 ppm in the starting material, to 7.50–
6.70 ppm in the spectrum of the photolyzed product, was
also observed. Similar chemical shift trends were identified
for the ester-containing norbornene derivatives. Further
spectral identification of all the products is listed in the ex-
perimental section.
Polymer syntheses
Ring-opening metathesis polymerizations were performed
using ruthenium-based catalysts, namely RuCl3(hydrate) and
(Cy3P)2Cl2Ru=CHPh. Polymerization of monomer 4 was ex-
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Can. J. Chem. Vol. 77, 1999
Scheme 5.
Table 2. ROMP results for polymers 21–24 using Grubbs’
Table 1. RuCl3(hydrate) polymerizations of compound 4 using
catalyst with [M]:[I] ratios of 100:1.
[M]:[I] ratios of 100:1.
Polymer
Mwa
Mnb
PDIc
Yield (%)
Solvent ratio (mL)
1.0 EtOH
0.97 EtOH/0.03 H2O 328 000
0.5 EtOH/0.5 H2O
1.0 H2O
Mwa
Mnb
87 000
125 000
248 000
177 000
PDIc
Yield (%)
21
22
23
24
108 000
462 000
145 000
74 000
57 000
1.9
2.4
1.7
1.5
71
74
73
66
298 000
3.4
2.6
2.1
2.2
32
45
73
82
195 000
87 000d
49 000d
535 000
397 000
aWeight-average molecular weight.
bNumber-average molecular weight.
cPolydispersity index.
aWeight-average molecular weight.
bNumber-average molecular weight.
cPolydispersity index.
dMolecular weights are representative of the soluble portions of the
polymer.
amined using a monomer to initiator ratio ([M]:[I]) of 100:1
with RuCl3(hydrate) as the catalyst. The catalyst was pre-
pared by stirring ruthenium trichloride hydrate in ethanol for
2 h; this solution was then added to monomer 4 and heated
at 60°C for 24 h yielding an off-white, fibrous solid (20) fol-
lowing precipitation into methanol. Previous investigations
using ruthenium chloride(hydrate) as a catalyst detail the ad-
vantages of using ethanol–water solvent mixtures, as it has
been noted that an increased amount of water yields higher
molecular weight polymers with lower polydispersities (PDI)
(71, 72). In keeping with this methodology, polymerizations
were carried out using varying ratios of ethanol to water as
observed in Table 1. Molecular weight determination of the
resulting polymeric materials was accomplished using gel
permeation chromatography (GPC). A weight-average mo-
lecular weight (Mw) of 298 000 was observed when using
100% EtOH, which increased up to 535 000 with a 50:50
EtOH/H2O mixture. Polymerization was also successful
when using 100% water, yielding a molecular weight of
397 000.
(Cy3P)2Cl2Ru=CHPh, by Grubbs and co-workers (29), has
led to the availability of a highly active metathesis catalyst.
This ruthenium-based system is of significant interest as it
offers mild reaction conditions and affords high conversion
rates of the monomer to the polymer. These catalysts also
show a marked improvement in their functional group toler-
ance, prompting our investigation into the polymerization of
the ester-bridged norbornene monomers.
The general methodology used in the preparation of these
polymeric materials involved the initial transfer of the cata-
lyst to the round-bottomed flask in a glove box. Initially, the
catalyst was dissolved in CH2Cl2, which was then added to a
CH2Cl2 solution of the monomer (9, 10, 18, 19). The result-
ing mixture was stirred at room temperature under a nitrogen
atmosphere until a gelatinous material formed, generally
within 1 h. An excess of ethyl vinyl ether was then added to
cleave the catalyst from the polymer chain. Subsequent pre-
cipitation from methanol gave off-white, fibrous polymeric
materials (21–24), as described in Scheme 5, in yields rang-
ing from 66 to 74%. GPC analyses of the polymers are de-
scribed in Table 2, showing Mw’s ranging from 74 000 to
462 000 for the variously functionalized polynorbornenes,
with PDIs from 1.5 to 2.4.
Ring-opening metathesis polymerization of the ester-
containing monomers with both ruthenium catalysts was also
attempted. Under analogous conditions to those employed
for monomer 4, monomer 9 was subjected to ROMP using
RuCl3(hydrate). Numerous attempts to polymerize this
monomer using this catalyst were unsuccessful. The recent
development of ruthenium benzylidene catalysts, namely
© 1999 NRC Canada

Abd-El-Aziz et al.
1803
Table 3. Various [M]:[I] ratios comparing Mw, Mn, PDI, and
yield for polymer 21.
found that as the length of the chain increased, the solubility
of the polymeric materials decreased. Polymers 23 and 24
demonstrated minimal solubility in CHCl3 at room tempera-
ture and only partial solubility when refluxed for 1 h. Low
solubility of the polymers was observed in both DMAc and
DMF; however, in DMSO, they remained completely insoluble.
Structural characterization of the polymers was most ef-
Yield
(%)
[M]:[I]
Mwa
Mnb
PDIc
25:1
50:1
100:1
150:1
8 400
16 000
108 000
511 000
3 900
6 500
57 000
168 000
2.2
2.5
1.9
3.0
59
52
71
80
1
fectively carried out using H and HH COSY NMR spec-
troscopy. As the monoarene-substituted polymers 20–22
demonstrated greater solubility in organic solvents in com-
parison to the oligoether polynorbornenes, higher resolution
NMR spectra could be obtained. The broadness of the aro-
matic peaks located between 8.05 and 7.95 ppm and be-
tween 7.60 and 7.30 ppm in 21 is characteristic of the
broadening effects associated with polymerization. More im-
portantly, successful polymerization was readily identifiable
by the shifting of the olefinic resonances from 6.20 to
6.01 ppm in the monomer (9) to 5.40–5.20 ppm in the poly-
mer (21). As this resonance appeared as a single broad band
and knowing that (Cy3P)2Cl2Ru=CHPh yields the trans
microstructure, it can be said with confidence that the
vinylene units exist in the trans configuration (32, 47).
FT-IR spectroscopy was useful in estimating the
microstructure of the polymeric materials by looking at the
respective cis and trans absorptions. Previous studies involv-
ing the geometry of polynorbornene and its derivatives have
found that cis in-plane = C-H bending occurs at 1404 and
740 cm–1, with the trans appearing at 960 cm–1 (22, 74, 75).
Comparison of monomer 9 with its respective polymer (21),
allowed for the peak at 969 cm–1 to be assigned to the trans
= C-H bending absorption. In addition, the absence of ab-
sorption in the regions of 1404 and 740 cm–1 confirmed the
lack of the cis configuration within the polymer.
Thermal analysis of the polymeric materials was per-
formed using differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA). In comparison to poly-
norbornene, which has a glass transition temperature (Tg) of
35°C (74), it was found that as the length of the aryl ether
chain increased, a noticeable increase in the Tg’s was ob-
tained. The results showed that the polymers containing sin-
gle arene units pendent to the polynorbornene backbone (20,
21) displayed a well-defined Tg at 55°C. Examination of the
penta-arene functionalized polymer (24) showed that the Tg
increased to 73°C, as shown in Table 4. The DSC
thermogram further verified the amorphous nature of the
trans-rich polynorbornene derivative, as no crystalline melt-
ing peaks were observed, which is consistent with previous
studies of trans polynorbornenes (73).
aWeight-average molecular weight.
bNumber-average molecular weight.
cPolydispersity index.
In an attempt to obtain higher molecular weight polymers
with narrow polydispersities, the reaction conditions were
altered by varying the [M]:[I] ratios to 25-, 50-, 100-, and
150:1 using monomer 9 as a model for these experiments
(Table 3). Ratios of 25:1 and 50:1 yielded fairly low molecu-
lar weight polymers with Mw’s of 8400 and 16 000 with
PDIs of 2.2 and 2.5, respectively. Polymerizations performed
using ratios of 100:1 yielded higher molecular weight poly-
norbornenes (108 000) with polydispersities of 1.9. When a
ratio of 150:1 was used, a significant increase in the molecu-
lar weight was obtained (511 000), although the PDI was
3.0. As a result of these observations, polymerizations were
consistently performed using [M]:[I] ratios of 100:1 with the
purpose of maintaining high molecular weight polymers
with low polydispersities.
To obtain a living polymer, complete consumption of the
monomer must be accomplished in such a way that initiation
proceeds faster than propagation (73). In an attempt to deter-
mine whether or not the ruthenium benzylidene polymeri-
zations were living, a ROMP reaction was conducted with
the intention of forming a homopolymer using monomer 9.
This proceeded with the withdrawal of a small portion of
polymer solution 1 h after the initial ROMP reaction com-
menced. A second aliquot of monomer 9 was then added to
the stirring polymer solution as a means to facilitate chain
growth by the continued propagation of the monomer. GPC
analysis of the polymer removed from solution after 1 h was
compared to the final polymer. Based upon the trace pro-
vided from the GPC plot, two significantly different peaks
were present for each of the polymers. The initial aliquot of
polymer removed from the reaction flask had a much lower
weight-average molecular weight (Mw = 22 600 g/mol, PDI
= 2.8) than the final polymer (Mw = 108 000 g/mol, PDI =
1.9). This increase in molecular weight provided definitive
evidence that the polymerization was living.
Polymer degradation was also investigated using TGA. It
was determined that as the number of aryl ether linkages in
the monomer increased, the polymeric material exhibited
higher thermal stability. This is in agreement with previous
findings for industrially prepared engineering thermoplastics
such as PEEK or PEKK, which demonstrate increased ther-
mal stability resulting from the high number of aromatic
ethers in the polymer backbone (10–12). Our results re-
vealed that this increase in aryl ether groups pendent to the
polynorbornene backbone allowed for greater thermal stabil-
ity, as defined by the increase in polymer degradation from
417°C for polymer 21 to 460°C for polymer 24. Further
thermal decomposition data is given in Table 4.
Polymer characterization
Solubility studies of the ether- and ester-bridged polymers
were performed as a means to assess their processability.
Chloroform (CHCl3), dimethylacetamide (DMAc), dimethyl-
formamide (DMF), and dimethylsulfoxide (DMSO) were all
examined to determine their suitability as solvents for dis-
solving the functionalized polynorbornenes. Polymers 20–22,
containing single aromatic groups pendent to the polynor-
bornene backbone, demonstrated good solubility in CHCl3
and DMAc at room temperature. However, DMF and DMSO
only partially solubilized the polymeric materials. With re-
spect to the longer pendent aromatic ether chains, it was
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Can. J. Chem. Vol. 77, 1999
Table 4. Thermal degradation temperatures for polymers 20–24.
Monomer syntheses
Nucleophilic substitution reaction. Preparation of complex
DSC (°C)
TGA (°C)
3
Polymer
Tga
Tonset
Tmidpoint
Tendset
Into a 50 mL round-bottom flask, 2.1 mmol (0.25 mL) of
20
21
22
23
24
54.9
54.7
65.3
67.6
73.3
374.6
385.3
354.3
393.9
408.5
418.7
417.0
401.9
422.4
460.2
461.2
450.6
427.5
456.8
509.6
2, 2.5 mmol (0.281 g) of potassium tert-butoxide, and 3 mL
of THF were stirred at room temperature for 1 h under a ni-
trogen atmosphere. Subsequently, 1.0 mmol (0.378 g) of 1
dissolved in 3 mL of THF and 1 mL of DMF was added to
the reaction flask and stirred for 16 h at room temperature
under nitrogen. The resulting solution was then filtered
through a sintered glass crucible into a 10% (v/v) HCl solu-
tion, resulting in the generation of a yellow solution. After
rinsing the reaction flask and crucible with a small amount
of CH2Cl2, a concentrated aqueous solution of NH4PF6 was
added. This solution was then extracted with CH2Cl2 (4 ×
50 mL) and the organic layer dried over MgSO4, filtered,
and the solvent removed by rotary evaporation. The resulting
dark orange oil (3) was rinsed with several aliquots of di-
aGlass transition temperatures (Tg’s) are reported as the midpoint.
Experimental section
General
1H and 13C NMR spectra were recorded at 200 and
50 MHz on a Gemini 200 NMR spectrometer and at 500 and
125 MHz on a Bruker 500 spectrometer, respectively. Chem-
ical shifts were calculated from the solvent that was used as
the internal reference and coupling constants were calculated
in Hz. IR spectra were recorded on a Bomem FT-IR spectro-
photometer. Mass spectra were obtained on a Hewlett–
Packard 5890 Series II mass spectrometer as well as on a
Hewlett–Packard 5989A mass spectrometer. Molecular
weight analyses by GPC were performed using a BL-gel
mixed D column (Phenomenex) equipped with a CH-30 col-
umn heater (Eppendorf) and a PL-DCU (Polymer Labora-
tories) detection system, with CHCl3 as the eluent at a flow
rate of 0.7 mL per min. Calibration of the instrument was
accomplished using polystyrene standards. Glass transition
temperatures were determined using differential scanning
calorimetry (DSC) performed on a Mettler DSC 25 at a heat-
ing rate of 10°C/min, taking the midpoint of the transition
from the second heating. Thermogravimetric analysis (TGA)
was recorded on a Mettler Toledo TGA/SDTA851 with a
heating rate of 10°C/min under a steady stream of nitrogen
(20 mL/min).
1
ethyl ether and dried under vacuum: 0.396 g (85%). H
NMR (500 MHz, CD3COCD3): (endo) δ (ppm): 6.40–6.30
(br m, 3H, ArH), 6.22 (m, 1H, J = 3.0 Hz and J = 5.3 Hz,
H5), 6.20–6.16 ppm (br d, 2H, ArH), 6.02 (m, 1H, J = 2.6
and 5.3 Hz, H6), 5.14 (br s, 5H, Cp), 4.02 (t, 1H, J = 9.1 Hz,
nor-CH2O), 3.87 (t, 1H, J = 7.1 Hz, nor-CH2O), 3.02 (br s,
1H, H1), 2.85 (br s, 1H, H4), 2.62–2.63 (br s, 1H, H2) 1.92–
1.94 (br m, 1H, H3x), 1.45 (br d, 1H, J = 7.8 Hz, H7s), 1.34
(br d, 1H, J = 7.8 Hz, H7a), 0.70 (m, 1H, J = 11.6 and
2.6 Hz, H3n); (exo) δ (ppm): 6.40–6.30 (br m, 3H, ArH),
6.20–6.16 (br d, 2H, ArH), 6.15 (m, 1H, H5), 6.13 (m, 1H,
H6), 5.14 (br s, 5H, Cp), 4.38 (t, 1H, J = 9.2 Hz, nor-CH2O),
4.19 (t, 1H, J = 6.5 Hz, nor-CH2O), 2.88 (br s, 2H, H1 and
H4), 2.06–2.04 (br m, 1H, H3x), 1.90–1.92 (br, 1H, H2), 1.49
(br d, 1H, H7s), 1.35 (br d, 1H, H7a), 1.31 (m, 1H, H3n). 13C
NMR (125 MHz, CD3COCD3): (endo) δ (ppm): 138.49 (1C,
C5), 135.04 (1C, quat ArC), 132.53 (1C, C6), 87.34 (2C,
ArC), 84.65 (1C, ArC), 77.06 (5C, Cp), 75.31 (2C, ArC),
73.87 (1C, nor-CH2O), 49.73 (1C, C7), 44.36 (1C, C1), 42.78
(1C, C4), 38.58 (1C, C2), 28.95 (1C, C3); (exo) δ (ppm):
137.64 (1C, C6), 136.70 (1C, C5), 135.13 (1C, quat ArC),
87.34 (2C, ArC), 84.65 (1C, ArC), 77.06 (5C, Cp), 75.31
(2C, ArC), 74.41 (1C, nor-CH2O), 45.30 (1C, C7), 44.17
(1C, C1), 42.22 (1C, C4), 38.91 (1C, C2), 29.51 (1C, C3).
Anal. calcd. for C19H21F6FeOP: C 48.95, H 4.54; found: C
48.75, H 4.61.
Materials
Preparation of the starting complex 1 was performed via
the previously reported ligand exchange reaction (76, 77).
Complexes 5 and 6 were prepared by the ligand exchange of
toluene and p-chlorotoluene, respectively, and their subse-
quent oxidation was previously described by Nesmeyanov et
al. (61). Complexes 12 and 14 were synthesized using previ-
ously reported methodologies (51). Anhydrous aluminum
chloride, aluminum powder, ferrocene, chloroarenes, ammo-
nium hexafluorophosphate, hydroquinone, 98%-exo,endo-5-
norbornene-2-methanol, dicyclohexylcarbodiimide, ruthe-
nium(III) chloride hydrate, and bis(tricyclohexyl-
phosphine)benzylidene ruthenium(IV) dichloride are all
commercially available and were used without further purifi-
cation. Pyridine was vacuum distilled over calcium chloride
and dried over 4 Å molecular sieves. All solvents (reagent
grade) were used without further purification, with the ex-
ception of tetrahydrofuran, which was distilled over sodium
metal under nitrogen gas. Silica gel 60–100 mesh, was used
in the column chromatographic purification of the liberated
arenes. Prior to polymerization, dichloromethane was dried
over calcium chloride, distilled, and then degassed by sev-
eral freeze–pump–thaw repetitions.
Condensation reaction. Preparation of complexes 7 and 8
Into a 25 mL round-bottom flask was placed 1.00 mmol
(0.422 g) of 5 or 6, 1.00 mmol (0.206 g) of DCC, and
1.654 mmol (0.20 mL) of 2. To this was added 10 mL of
CH2Cl2 followed by four drops of pyridine. The reaction
mixture was gently stirred at room temperature for 7 h (7) or
3 h (8), resulting in the formation of a heterogeneous yellow
solution. Due to the precipitation of dicyclohexylurea (DCU)
from the reaction mixture, the solution was gravity filtered,
rinsed with 2 × 10 mL portions of CH2Cl2, and then
rotovaped to dryness. The resulting yellow viscous material
was dissolved in a minimal amount of acetone and filtered
once again to remove the remaining DCU. Precipitation of
the crude product into diethyl ether and subsequent cooling
in the freezer overnight yielded the pure complex as a yel-
low semi-crystalline material.
© 1999 NRC Canada

Abd-El-Aziz et al.
1805
Complex 7: 0.306 g (62%). IR (cm–1): 1733 (CO). 1H NMR
(200 MHz, CD3COCD3): (endo) δ (ppm): 7.05 (d, 2H, ArH),
6.72 (m, 3H, ArH), 6.23 (m, 1H, H5), 6.08 (m, 1H, H6), 5.28
(s, 5H, Cp), 4.23 (q, 1H, nor-CH2O), 4.05 (t, 1H, nor-
CH2O), 3.07 (br s, 1H, H1), 2.84 (br s, 1H, H4), 2.66 (m, 1H,
H2), 1.97 (br m, 1H, H3x), 1.46 (br s, 1H, H7s), 1.34 (br d,
1H, H7a), 0.73 (m, 1H, H3n); (exo) δ (ppm): 7.05 (d, 2H,
ArH), 6.72 (m, 3H, ArH), 6.15 (m, 1H, H5), 6.14 (m, 1H,
H6), 5.28 (s, 5H, Cp), 4.56 (q, 1H, nor-CH2O), 4.39 (t, 1H,
nor-CH2O), 2.89 (br s, 2H, H1 and H4), 2.13 (br m, 1H, H3x),
1.93 (br m, 1H, H2), 1.45 (br s, 1H, H7s), 1.37 (br d, 1H,
H7a), 1.31 (br m, 1H, H3n). 13C NMR (50 MHz,
CD3COCD3): (endo) δ (ppm): 165.96 (1C, CO), 138.50 (1C,
C5), 132.78 (1C, C6), 90.94 (1C, ArC), 89.96 (2C, ArC),
89.40 (2C, ArC), 79.21 (5C, Cp), 70.83 (1C, nor-CH2O),
49.91 (1C, C7), 44.64 (1C, C1), 42.94 (1C, C4), 38.36 (1C,
C2), 29.79 (1C, C3); (exo) δ (ppm): 166.02 (1C, CO), 137.69
(1C, C6), 132.78 (1C, C5), 90.94 (1C, ArC), 89.96 (2C,
ArC), 89.40 (2C, ArC), 79.21 (5C, Cp), 71.51 (1C, nor-
CH2O), 45.52 (1C, C7), 44.39 (1C, C1), 42.35 (1C, C4),
38.73 (1C, C2), 29.40 (1C, C3). Anal. calcd. for
C20H21F6FeO2P: C 48.61, H 4.28; found: C 48.37, H 4.33.
product as a yellow solid allowed for isolation of the com-
plex in very high yield.
Complex 15: 0.811
g
(90%). 1H NMR (200 MHz,
CD3COCD3): δ (ppm): 8.72 (s, 1H, -OH), 7.55 (s, 4H,
uncomplexed ArH), 7.19 (d, 2H, J = 6.9 Hz, uncomplexed
ArH), 7.00 (d, 2H, J = 7.6 Hz, uncomplexed ArH), 6.45–
6.23 (br m, 9H, complexed ArH), 5.31 (s, 5H, Cp), 5.25 (s,
5H, Cp). 13C NMR (50 MHz, CD3COCD3): δ (ppm): 156.30
(1C, uncomplexed quat C), 152.32 (1C, uncomplexed quat
C), 151.57 (1C, uncomplexed quat C), 146.45 (1C,
uncomplexed quat C), 134.51 (1C, complexed quat C),
132.98 (1C, complexed quat C), 131.70 (1C, complexed quat
C), 124.42 (2C, uncomplexed ArC), 124.11 (2C,
uncomplexed ArC), 122.90 (2C, uncomplexed ArC), 117.87
(2C, uncomplexed ArC), 87.80 (2C, complexed ArC), 85.81
(1C, complexed ArC), 78.80 (5C, Cp), 78.13 (5C, Cp), 77.58
(2C, complexed ArC), 75.71 (2C, complexed ArC), 74.79
(2C, complexed ArC). Anal. calcd. for C34H28F12Fe2O4P2: C
45.26, H 3.13; found: C 45.37, H 3.31.
Nucleophilic substitution reactions. Preparation of
complexes 16 and 17
Typically, 1.00 mmol of the phenolic complex (14 or 15)
was added to 1.00 mmol of 8 along with 2.50 mmol of po-
tassium carbonate. To this was added 10 mL of DMF, and
the reaction mixture was allowed to stir at room temperature
under a N2 atmosphere for 16 h. The resulting solution was
then poured into 10% (v/v) HCl and formed a yellow precip-
itate upon addition of a concentrated solution of NH4PF6.
Complex 8: 0.370 g (70%). IR (cm–1): 1733 (CO). 1H NMR
(500 MHz, CD3COCD3): (endo) δ (ppm): 7.14 (d, 2H, J =
6.7 Hz, ArH), 7.01 (d, 2H, J = 6.7 Hz, ArH), 6.21 (m, 1H, J
= 3.1 and 5.5 Hz, H5), 6.05 (m, 1H, J = 2.6 and 5.5 Hz, H6),
5.36 (s, 5H, Cp), 4.20 (q, 1H, J = 6.8 and 10.5 Hz, nor-
CH2O), 4.03 (t, 1H, J = 9.5 and 10.5 Hz, nor-CH2O), 3.04
(br s,1H, H1), 2.84 (br s, 1H, H4), 2.64 (m, 1H, H2), 1.96
(m,1H, J = 3.7 and J = 8.9 Hz, H3x), 1.42 (d, 1H, H7s), 1.32
(d, 1H, H7a), 0.67 (m,1H, J = 2.4 and 11.7 Hz, H3n); (exo) δ
(ppm): 7.14 (d, 2H, J = 6.7 Hz, ArH), 7.01 (d, 2H, J =
6.7 Hz, ArH), 6.14 (m, 1H, J = 2.3 Hz, H5), 6.10 (m, 1H, J
= 2.3 Hz, H6), 5.36 (s, 5H, Cp), 4.53 (q, 1H, J = 6.8 and
10.8 Hz, nor-CH2O), 4.36 (t, 1H, J = 9.1 Hz, nor-CH2O),
2.86 (br s, 2H, H1 and H4), 2.15 (br, 1H, H3x), 1.92 (m, 1H,
H2), 1.41 (br d, 1H, H7s), 1.33 (br d, 1H, H7a), 1.30 (m, 1H,
H3n). 13C NMR (125 MHz, CD3COCD3): (endo) δ (ppm):
165.09 (1C, CO), 138.45 (1C, C5), 132.79 (1C, C6), 109.58
(1C, quat ArC), 90.19 (2C, ArC), 89.28 (2C, ArC), 81.47
(5C, Cp), 71.12 (1C, nor-CH2O), 49.92 (1C, C7), 44.59 (1C,
C1), 42.90 (1C, C4), 38.26 (1C, C2), 29.77 (1C, C3); (exo) δ
(ppm): 165.19 (1C, CO), 137.57 (1C, C6), 136.93 (1C, C5),
109.58 (1C, quat ArC), 90.19 (2C, ArC), 89.28 (2C, ArC),
81.47 (5C, Cp), 71.78 (1C, nor-CH2O), 45.50 (1C, C7),
44.37 (1C, C1), 42.31 (1C, C4), 38.60 (1C, C2), 29.46 (1C,
C3). Anal. calcd. for C20H20ClF6FeO2P: C 45.44, H 3.81;
found: C 45.70, H 4.00.
Complex 16: 0.495 g (81%). IR (cm–1): 1732 (CO). 1H
NMR (200 MHz, CD3COCD3): (endo) δ (ppm): 7.55 (br s,
4H, uncomplexed ArH), 7.05 (br s, 2H, complexed ArH),
6.67 (br s, 2H, complexed ArH), 6.46 (br s, 5H, complexed
ArH), 6.33 (m, 1H, H5), 6.08 (m, 1H, H6), 5.33 (s, 5H, Cp),
5.26 (s, 5H, Cp), 4.23 (q, 1H, nor-CH2O), 4.07 (t, 1H, nor-
CH2O), 3.06 (br s,1H, H1), 2.82 (br s, 1H, H4), 2.66 (m, 1H,
H2), 1.97 (m,1H, H3x), 1.46 (br d, 1H, H7s), 1.36 (br d,1H,
H7a), 0.73 (m,1H, H3n); (exo) δ (ppm): 7.55 (br d, 4H,
uncomplexed ArH), 7.05 (s, 2H, complexed ArH), 6.67 (s,
2H, complexed ArH), 6.46 (br s, 5H, complexed ArH), 6.24
(m, 1H, H5), 6.14 (m, 1H, H6), 5.33 (s, 5H, Cp), 5.26 (s, 5H,
Cp), 4.55 (q, 1H, nor-CH2O), 4.42 (t, 1H, nor-CH2O), 2.88
(br s, 2H, H1 and H4), 2.15 (br m, 1H, H3x), 1.95 (m, 1H,
H2), 1.44 (br d, 1H, H7s), 1.38 (br d, 1H, H7a), 1.30 (m, 1H,
H3n). 13C NMR (50 MHz, CD3COCD3): (endo) δ (ppm):
165.62 (1C, CO), 151.92 (1C, uncomplexed quat ArC),
151.40 (1C, uncomplexed quat ArC), 138.46 (1C, C5),
136.25 (1C, complexed quat ArC), 134.65 (1C, complexed
quat ArC), 132.85 (1C, C6), 124.67 (2C, uncomplexed ArC),
124.56 (2C, uncomplexed ArC), 88.34 (2C, complexed
ArC), 87.87 (2C, complexed ArC), 85.87 (1C, complexed
ArC), 79.71 (5C, Cp), 78.19 (5C, Cp), 77.99 (2C, complexed
ArC), 77.67 (2C, complexed ArC), 70.86 (1C, nor-CH2O),
49.94 (1C, C7), 44.69 (1C, C1), 42.92 (1C, C4), 38.36 (1C,
C2), 29.81 (1C, C3); (exo) δ (ppm): 165.71 (1C, CO), 151.92
(1C, uncomplexed quat ArC), 151.40 (1C, uncomplexed quat
ArC), 137.59 (1C, C6), 136.99 (1C, C5), 136.25 (1C,
complexed quat ArC), 134.65 (1C, complexed quat ArC),
124.67 (2C, uncomplexed ArC), 124.56 (2C, uncomplexed
ArC), 88.34 (2C, complexed ArC), 87.87 (2C, complexed
Nucleophilic substitution reactions. Preparation of complex
15
Into a 50 mL round-bottom flask, 1.00 mmol of 12 was
combined with 8.00 mmol (0.881 g) of hydroquinone (13)
and 2.00 mmol (0.276 g) of potassium carbonate. These re-
agents were stirred and refluxed for 16 h at 65°C in 16 mL
of THF and 4 mL of DMF under an inert N2 atmosphere. Af-
ter cooling to room temperature, the reaction mixture was
poured into 10% (v/v) HCl, and to this was added a concen-
trated solution of NH4PF6. Immediate precipitation of the
© 1999 NRC Canada

1806
Can. J. Chem. Vol. 77, 1999
ArC), 85.87 (1C, complexed ArC), 79.71 (5C, Cp), 78.19
(5C, Cp), 77.99 (2C, complexed ArC), 77.67 (2C,
complexed ArC), 71.52 (1C, nor-CH2O), 45.56 (1C, C7),
44.45 (1C, C1), 42.35 (1C, C4), 38.74 (1C, C2), 29.42 (1C,
C3). Anal. calcd. for C37H34F12Fe2O4P2: C 47.06, H 3.63;
found: C 47.34, H 3.61.
photochemical apparatus equipped with a xenon lamp and ir-
radiated at room temperature for 4–8 h, the time increasing
as the number of metal moieties increased. After this time,
the solvent was removed by rotary evaporation, and the con-
tents were dissolved in CHCl3 and washed with several
aliquots of water (3 × 50 mL). The resulting solution was
dried over MgSO4, gravity filtered, and then evaporated un-
der reduced pressure. Using a minimal amount of CH2Cl2
(1–2 mL), the crude product was transferred to a silica gel
column, which was eluted first with hexane and then CHCl3.
Once again, the solvent was removed by rotary evaporation,
liberating the arene–norbornene derivatives in good yields.
Complex 17: 1.02 g (86%). IR (cm–1): 1732 (CO). 1H NMR
(200 MHz, CD3COCD3): (endo) δ (ppm): 7.64 (br s, 4H,
uncomplexed ArH), 7.61 (br s, 4H, uncomplexed ArH), 7.18
(br s, 2H, complexed ArH), 7.05 (br s, 2H, complexed ArH),
6.68–6.31 (br m, 9H, complexed ArH), 6.28 (m, 1H, H5),
6.13 (m, 1H, H6), 5.34 (s, 5H, Cp), 5.32 (s, 5H, Cp), 5.26 (s,
5H, Cp), 4.24 (m, 1H, nor-CH2O), 4.01 (br t, 1H, nor-
CH2O), 3.08 (br s,1H, H1), 2.81 (br s, 1H, H4), 2.76 (br m,
1H, H2), 2.00 (m, 1H, H3x), 1.53 (br d, 1H, H7s), 1.35 (br d,
1H, H7a), 0.71 (m, 1H, H3n); (exo) δ (ppm): 7.64 (br s, 4H,
uncomplexed ArH), 7.61 (br s, 4H, uncomplexed ArH), 7.18
(br s, 2H, complexed ArH), 7.05 (br s, 2H, complexed ArH),
6.68–6.31 (br m, 9H, complexed ArH), 6.22 (m, 1H, H5),
6.20 (m, 1H, H6), 5.34 (s, 5H, Cp), 5.32 (s, 5H, Cp), 5.26 (s,
5H, Cp), 4.56 (m, 1H, nor-CH2O), 4.37 (t, 1H, nor-CH2O),
2.87 (br s, 2H, H1 and H4), 2.13–2.04 (br m, 1H, H3x), 1.93
(br m, 1H, H2), 1.44 (br d, 1H, H7s), 1.37 (br d, 1H, H7a),
1.34 (br m, 1H, H3n). 13C NMR (50 MHz, CD3COCD3):
(endo) δ (ppm): 165.59 (1C, CO), 152.30 (1C, uncomplexed
quat ArC), 152.03 (1C, uncomplexed quat ArC), 151.61 (1C,
uncomplexed quat ArC), 151.36 (1C, uncomplexed quat
ArC),138.47 (1C, C5), 136.34 (1C, complexed quat ArC),
134.68 (1C, complexed quat ArC), 132.88 (1C, C6), 132.25
(2C, complexed quat ArC), 124.68 (2C, uncomplexed ArC),
124.62 (2C, uncomplexed ArC), 124.50 (2C, uncomplexed
ArC), 124.46 (2C, uncomplexed ArC), 88.26 (2C,
complexed ArC), 87.76 (2C, complexed ArC), 85.77 (1C,
complexed ArC), 79.60 (5C, Cp), 78.97 (5C, Cp), 78.08 (5C,
Cp), 77.71 (2C, complexed ArC), 77.39 (2C, complexed
ArC), 75.36 (2C, complexed ArC), 75.34 (2C, complexed
ArC), 70.81 (1C, nor-CH2O), 49.95 (1C, C7), 44.64 (1C,
C1), 42.94 (1C, C4), 38.35 (1C, C2), 29.81 (1C, C3); (exo) δ
(ppm): 165.69 (1C, CO), 152.30 (1C, uncomplexed quat
ArC), 152.03 (1C, uncomplexed quat ArC), 151.61 (1C,
uncomplexed quat ArC), 151.36 (1C, uncomplexed quat
ArC), 137.53 (1C, C6), 136.99 (1C, C5), 136.34 (1C,
complexed quat ArC), 134.68 (1C, complexed quat ArC),
132.25 (2C, complexed quat ArC), 124.68 (2C,
uncomplexed ArC), 124.62 (2C, uncomplexed ArC), 124.50
(2C, uncomplexed ArC), 124.46 (2C, uncomplexed ArC),
88.26 (2C, complexed ArC), 87.76 (2C, complexed ArC),
85.77 (1C, complexed ArC), 79.60 (5C, Cp), 78.97 (5C, Cp),
78.08 (5C, Cp), 77.71 (2C, complexed ArC), 77.39 (2C,
complexed ArC), 75.36 (2C, complexed ArC), 75.34 (2C,
complexed ArC), 71.47 (1C, nor-CH2O), 46.56 (1C, C7),
44.42 (1C, C1), 42.36 (1C, C4), 38.75 (1C, C2), 29.42 (1C,
C3). Anal. calcd. for C54H47F18Fe3O6P3: C 46.51, H 3.40;
found: C 46.49, H 3.56.
1
Compound 4: 0.166 g (83%). H NMR (500 MHz, CDCl3):
(endo) δ (ppm): 7.50–6.70 (5H, ArH), 6.19 (m, 1H, J = 3.0
and 5.6 Hz, H5), 5.98 (m, 1H, J = 2.9 and 5.6 Hz, H6), 3.73
(t, 1H, J = 9.3 Hz, nor-CH2O), 3.57 (t, 1H, J = 6.5 Hz, nor-
CH2O), 3.07 (br s, 1H, H1), 2.87 (br s, 1H, H4), 2.62–2.56
(m, 1H, J = 6.5 Hz, H2) 1.97–1.91 (m, 1H, J = 9.4, 11.6, and
2.6 Hz, H3x), 1.51 (br s, 1H, J = 2.6 and 8.1 Hz, H7s), 1.33
(br s, 1H, J = 8.1 Hz, H7a), 0.70 (m, 1H, J = 4.3, 11.6, and
2.6 Hz, H3n); (exo) δ (ppm): 7.50–6.70 (5H, ArH), 6.18 (m,
1H, H5), 6.13 (m, 1H, H6), 4.05 (t, 1H, J = 9.1 Hz, nor-
CH2O), 3.87 (t, 1H, J = 6.2 Hz, nor-CH2O), 2.90 (br s, 1H,
H4), 2.87 (br s, 1H, H1), ~1.92 (m, 1H, H2), 1.50 (br s, 2H,
H7s and H7a), 1.37 (m, 1H, H3n), 1.27 (m, 1H, H3x). 13C
NMR (125 MHz, CDCl3): (endo) δ (ppm): 159.21 (1C, quat
ArC), 137.45 (1C, C5), 132.37 (1C, C6), 129.43 (2C, ArC),
120.55 (1C, ArC), 115 (2C, ArC), 71.38 (1C, nor-CH2O),
49.41 (1C, C7), 43.96 (1C, C1), 41.65 (1C, C4), 38.42 (1C,
C2), 29.06 (1C, C3); (exo) δ (ppm): 159.21 (1C, quat ArC),
136.78 (1C, C6), 136.47 (1C, C5), 129.43 (2C, ArC), 120.55
(1C, ArC), 114.61 (2C, ArC), 72.24 (1C, nor-CH2O), 45.10
(1C, C7), 43.78 (1C, C4), 42.29 (1C, C1), 38.65 (1C, C2),
29.72 (1C, C3). MS, m/z; M+ 200. Anal calcd. for C14H16O:
C 83.96, H 8.05; found: C 83.81, H 8.12.
Compound 9: 0.160 g (70%). IR (cm–1): 1714 (CO). 1H
NMR (500 MHz, CDCl3): (endo) δ (ppm): 8.07 (d, 2H, J =
8.0 Hz, ArH), 7.55 (t, 1H, J = 7.2 Hz, ArH), 7.44 (t, 2H, J =
8.1 Hz, ArH), 6.20 (m, 1H, J = 3.0 and 5.7 Hz, H5), 6.01 (m,
1H, J = 2.8 and 5.7 Hz, H6), 4.13 (q, 1H, J = 10.8 Hz, nor-
CH2O), 3.91 (t, 1H, J = 10.8 Hz, nor-CH2O), 2.99 (br s, 1H,
H1), 2.85 (br s, 1H, H4), 2.55 (m, 1H, H2) 1.90 (m, 1H, H3x),
1.49 (br d, 1H, H7s), 1.30 (br d, 1H, H7a), 0.67 (m, 1H, J =
2.6, 4.2, and 11.7 Hz, H3n); (exo) δ (ppm): 8.07 (d, 2H, J =
8.0 Hz, ArH), 7.55 (t, 1H, J = 7.2 Hz, ArH), 7.44 (t, 2H, J =
8.1 Hz, ArH), 6.13 (m, 1H, J = 3.1 and 5.6 Hz, H5), 6.11 (m,
1H, J = 2.9 and 5.6 Hz, H6), 4.42 (q, 1H, J = 10.9 Hz, nor-
CH2O), 4.22 (t, 1H, J = 10.9 Hz, nor-CH2O), 2.88 (br s, 1H,
H4), 2.82 (br s, 1H, H1), 1.90 (m, 1H, H2), 1.40 (br s, 2H,
H7s and H7a), 1.34 (m, 1H, H3n), 1.26 (m, 1H, H3x). 13C
NMR (125 MHz, CDCl3): (endo) δ (ppm): 166.45 (1C, CO),
137.57 (1C, C5), 132.73 (1C, ArC), 132.16 (1C, C6), 130.54
(1C, quat ArC), 129.50 (2C, ArC), 128.26 (2C, ArC), 68.26
(1C, nor-CH2O), 49.35 (1C, C7), 43.95 (1C, C1), 42.19 (1C,
C4), 37.88 (1C, C2), 28.93 (1C, C3); (exo) δ (ppm): 166.55
(1C, CO), 136.92 (1C, C6), 136.19 (1C, C5), 132.73 (1C,
ArC), 130.46 (1C, quat ArC), 129.50 (2C, ArC), 128.26 (2C,
ArC), 68.94 (1C, nor-CH2O), 44.97 (1C, C7), 43.71 (1C,
C1), 41.59 (1C, C4), 38.08 (1C, C2), 29.56 (1C, C3). MS,
Photolytic demetallation. Preparation of compounds 4, 9,
10, 18, and 19
Each of the complexes, 3, 7, 8, 16, and 17, were dissolved
in a 4:1 mixture of CH2Cl2:CH3CN, and transferred to a Py-
rex photolytic tube. The reaction tube was then fitted into a
© 1999 NRC Canada

Abd-El-Aziz et al.
1807
m/z: M+ 228. Anal. calcd. for C15H16O2: C 78.92, H 7.06;
found: C 78.54, H 7.12.
H4), 2.54 (br m, 1H, H2), 1.90 (br m, 1H, H3x), 1.48 (br s,
1H, H7s), 1.30 (br s, 1H, H7a), 0.66 (br m, 1H, H3n); (exo) δ
(ppm): 8.02 (br d, 2H, ArH), 7.33 (br, 2H, ArH), 7.09–6.92
(br m, 17H, ArH), 6.12 (m, 2H, H5 and H6), 4.39 (q, 1H,
nor-CH2O), 4.21 (t, 1H, nor-CH2O), 2.88 (br s, 1H, H4),
2.80 (br s, 1H, H1), 1.88 (br m, 1H, H2), 1.40 (br s, 2H, H7s
and H7a), 1.34 (br m, 1H, H3n), 1.27 (br m, 1H, H3x). 13C
NMR (50 MHz, CDCl3): (endo) δ (ppm): 165.98 (1C, CO),
162.08 (1C, quat ArC), 162.06 (1C, quat ArC), 157.72 (1C,
quat ArC), 154.34 (1C, quat ArC), 153.33 (1C, quat ArC),
153.11 (1C, quat ArC), 152.58 (1C, quat ArC), 150.72 (1C,
quat ArC), 137.61 (1C, C5), 132.18 (1C, C6), 131.63 (2C,
ArC), 129.70 (2C, ArC), 122.86 (1C, ArC), 121.63 (2C,
ArC), 120.45 (2C, ArC), 120.20 (2C, ArC), 119.86 (2C,
ArC), 119.83 (2C, ArC), 119.69 (2C, ArC), 118.20 (2C,
ArC), 116.74 (2C, ArC), 68.18 (1C, nor-CH2O), 49.35 (1C,
C7), 43.94 (1C, C1), 42.19 (1C, C4), 37.87 (1C, C2), 28.92
(1C, C3); (exo) δ (ppm): 166.04 (1C, CO), 162.08 (1C, quat
ArC), 162.06 (1C, quat ArC), 157.72 (1C, quat ArC), 154.34
(1C, quat ArC), 153.33 (1C, quat ArC), 153.11 (1C, quat
ArC), 152.58 (1C, quat ArC), 150.72 (1C, quat ArC), 136.95
(1C, C6), 136.21 (1C, C5), 131.63 (2C, ArC), 129.70 (2C,
ArC), 122.86 (1C, ArC), 121.63 (2C, ArC), 120.45 (2C,
ArC), 120.20 (2C, ArC), 119.86 (2C, ArC), 119.83 (2C,
ArC), 119.69 (2C, ArC), 118.20 (2C, ArC), 116.74 (2C,
ArC), 68.84 (1C, nor-CH2O), 44.98 (1C, C7), 43.69 (1C,
C1), 41.59 (1C, C4), 37.87 (1C, C2), 28.92 (1C, C3). MS,
m/z: M+ 597. Anal. calcd. for C39H32O6: C 78.51, H 5.41;
found: C 78.28, H 5.49.
1
Compound 10: 0.168 g (64%). IR (cm–1): 1715 (CO). H
NMR (500 MHz, CDCl3): (endo) δ (ppm): 7.97 (d, 2H,
ArH), 7.39 (d, 2H, ArH), 6.17 (m, 1H, H5), 5.98 (m, 1H,
H6), 4.09 (q, 1H, J = 6.6 and. 10.9 Hz, nor-CH2O), 3.88 (t,
1H, J = 9.3 Hz, nor-CH2O), 2.94 (br s, 1H, H1), 2.83 (br s,
1H, H4), 2.52 (m, 1H, H2) 1.89 (m, 1H, H3x), 1.46 (br s, 1H,
H7s), 1.28 (br s, 1H, H7a), 0.63 (m, 1H, H3n); (exo) δ (ppm):
7.97 (d, 2H, ArH), 7.39 (d, 2H, ArH), 6.11 (m, 1H, H5), 6.10
(m, 1H, H6), 4.38 (q, 1H, J = 10.1 Hz, nor-CH2O), 4.20 (t,
1H, J = 6.6 Hz, nor-CH2O), 2.85 (br s, 1H, H4), 2.77 (br s,
1H, H1), 1.86 (m, 1H, H2), 1.37 (br s, 2H, H7s and H7a), 1.32
(m, 1H, H3n), 1.27 (m, 1H, H3x). 13C NMR (125 MHz,
CDCl3): (endo) δ (ppm): 165.42 (1C, CO), 139.05 (1C, quat
ArC), 137.56 (1C, C5), 131.99 (1C, C6), 130.80 (2C, ArC),
128.80 (1C, quat ArC), 128.50 (2C, ArC), 68.40 (1C, nor-
CH2O), 49.28 (1C, C7), 43.86 (1C, C1), 42.11 (1C, C4),
37.77 (1C, C2), 28.85 (1C, C3); (exo) δ (ppm): 165.52 (1C,
CO), 139.12 (1C, quat ArC), 136.86 (1C, C6), 136.04 (1C,
C5), 130.80 (2C, ArC), 128.88 (1C, quat ArC), 128.50 (2C,
ArC), 69.09 (1C, nor-CH2O), 44.88 (1C, C7), 43.60 (1C,
C1), 41.50 (1C, C4), 37.96 (1C, C2), 29.48 (1C, C3). MS,
m/z: M+ 262. Anal. calcd. for C15H15ClO2: C 68.57; H. 5.75;
found: C 68.23, H 5.95.
1
Compound 18: 0.210 g (51%). IR (cm–1): 1707 (CO). H
NMR (200 MHz, CDCl3): (endo) δ (ppm): 8.05 (br d, 2H,
ArH), 7.38 (br, 2H, ArH), 7.15–6.98 (br m, 9H, ArH), 6.21
(m, 1H, H5), 6.02 (m, 1H, H6), 4.10 (q, 1H, nor-CH2O), 3.90
(t, 1H, nor-CH2O), 2.98 (br s, 1H, H1), 2.87 (br s, 1H, H4),
2.55 (m, 1H, H2), 1.91 (br m, 1H, H3x), 1.50 (br d, 1H, H7s),
1.32 (br s, 1H, H7a), 0.64 (m, 1H, H3n); (exo) δ (ppm): 8.05
(br d, 2H, ArH), 7.38 (br d, 2H, ArH), 7.15–6.98 (br m, 9H,
ArH), 6.13 (m, 1H, H5), 6.11 (m, 1H, H6), 4.40 (q, 1H, nor-
CH2O), 4.21 (t, 1H, nor-CH2O), 2.89 (br s, 1H, H4), 2.82
(br s, 1H, H1), 1.84 (br m, 1H, H2), 1.40 (br s, 2H, H7s and
H7a), 1.34 (br m, 1H, H3n), 1.25 (br m, 1H, H3x). 13C NMR
(50 MHz, CDCl3): (endo) δ (ppm): 165.98 (1C, CO), 162.05
(1C, quat ArC), 157.36 (1C, quat ArC), 153.75 (1C, quat
ArC), 150.93 (1C, quat ArC), 137.61 (1C, C5), 132.19 (1C,
C6), 131.66 (2C, ArC), 129.79 (2C, ArC), 124.62 (1C, quat
ArC), 123.28 (1C, ArC), 121.51 (2C, ArC), 120.36
(2C,ArC), 118.56 (2C, ArC), 116.79 (2C, ArC), 68.17 (1C,
nor-CH2O), 49.35 (1C, C7), 43.95 (1C, C1), 42.19 (1C, C4),
37.89 (1C, C2), 28.92 (1C, C3); (exo) δ (ppm): 166.04 (1C,
CO), 162.05 (1C, quat ArC), 157.36 (1C, quat ArC), 153.75
(1C, quat ArC), 150.93 (1C, quat ArC), 136.96 (1C, C6),
136.22 (1C, C5), 131.66 (2C, ArC), 129.79 (2C, ArC),
124.71 (1C, quat ArC), 123.28 (1C, ArC), 121.51 (2C, ArC),
120.36 (2C,ArC), 118.56 (2C, ArC), 116.79 (2C, ArC),
68.84 (1C, nor-CH2O), 44.99 (1C, C7), 43.69 (1C, C1), 41.60
(1C, C4), 37.89 (1C, C2), 28.92 (1C, C3). MS, m/z: M+ 412.
Anal. calcd. for C27H24O4; C 78.62, H 5.86; found: C 78.84,
H 5.80.
Polymer syntheses
RuCl3(hydrate) polymerization. Preparation of polymer 20
In a 10 mL round-bottom flask, 1 mol % of RuCl3(hy-
drate) was stirred in the previously described ethanol or wa-
ter solvent system (71, 72). Generation of the catalyst
proceeded under a nitrogen atmosphere for 2–3 h, after
which it was added to the monomer (4). The resulting solu-
tion was heated at 60°C for a 24 h period, yielding a viscous
material. After dissolution in CHCl3, the polymer was pre-
cipitated into methanol with vigorous stirring. A fibrous, off-
white solid was obtained following this purification process.
IR (cm–1): 1714 (CO), 969 (trans olefin). 1H NMR
(200 MHz, CDCl3): δ (ppm): 7.30–7.10 (br s, 2H, ArH),
6.90–6.70 (br s, 3H, ArH), 5.40–5.25 (br s, 2H, olefinic H),
3.90–3.60 (br d, 2H, poly-CH2O), 2.90–1.10 (br peaks, 7H,
aliphatic ring protons).
(Cy3P)2Cl2Ru=CHPh polymerizations. Preparation of
polymers 21–24
Using [M]:[I] ratios of 100:1, the catalyst was weighed
out in a glove box and transferred to a 10 mL RBF. To this
flask was added 0.5 mL of CH2Cl2 for every 100 mg of
monomer used. Outside of the glovebox, another equivalent
of CH2Cl2 (0.5 mL/100 mg) was added to a second 10 mL
round-bottom flask containing the monomer under a N2 at-
mosphere. Using an airtight syringe, the catalyst solution
was then transferred under N2 to the vigorously stirring
monomer. The polymerization reaction proceeded for ap-
proximately 1 h, giving a gelatinous material. To this, a
small volume of ethyl vinyl ether was added. The polymer
1
Compound 19: 0.275 g (46%). IR (cm–1): 1716 (CO). H
NMR (200 MHz, CDCl3): (endo) δ (ppm): 8.02 (br d, 2H,
ArH), 7.33 (br d, 2H, ArH), 7.09–6.92 (br m, 17H, ArH),
6.20 (m, 1H, H5), 6.00 (m, 1H, H6), 4.10 (q, 1H, nor-CH2O),
3.89 (t, 1H, nor-CH2O), 2.97 (br s, 1H, H1), 2.86 (br s, 1H,
© 1999 NRC Canada

1808
Can. J. Chem. Vol. 77, 1999
13. P.M. Hergenrother, B.J. Jensen, and S.J. Havens. Polymer, 88,
358 (1988).
was then dissolved in either CH2Cl2 or CHCl3 and precipi-
tated into methanol yielding a fibrous, off-white material.
14. M. Ueda and F. Ichikawa. Macromolecules, 23, 926 (1990).
15. S. Matsumoto, K. Komatsu, and K. Igarashi. Ring-opening
Polym. Int. Symp. ACS Symp. Ser. (303) 1977.
16. R. Madan, R.C. Anand, and I.K. Varma. Ind. J. Chem. Tech. 5,
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17. S.C.G. Biagini, M.P. Coles, V.C. Gibson, M.R. Giles, E.L.
Marshall, and M. North. Polymer, 39, 1007 (1998).
18. V. Heroguez, S. Breunig, Y. Gnanou, and M. Fontanille.
Macromolecules, 29, 4459 (1996).
19. B.S. Heinz, W. Heitz, S.A. Krugel, F. Raubacher, and J.H.
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20. M.A. Tlenkopatchev, S. Fomine, L. Fomina, R. Gavino, and T.
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21. M.R. Buchmeiser, N. Atzl, and G.K. Bonn. J. Am. Chem. Soc.
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Soc. 114, 3974 (1992).
Poymer 21: 0.220 g (71%). IR (cm–1): 1714 (CO), 969
(trans olefin). H NMR (500 MHz, CDCl3): δ (ppm): 8.05–
7.95 (br s, 2H, ArH), 7.60–7.30 (br, 3H, ArH), 5.40–5.20
(br s, 2H, olefinic H), 4.40–4.05 (br d, 2H, poly-CH2O),
3.10–1.19 (br peaks, 7H, aliphatic ring protons).
1
Polymer 22: 0.270 g (74%). IR (cm–1): 1715 (CO), 969
1
(trans olefin). H NMR (200 MHz, CDCl3): δ (ppm): 8.01–
7.90 (br s, 2H, ArH), 7.45–7.35 (br s, 2H, ArH), 5.40–5.20
(br s, 2H, olefinic H), 4.35–4.05 (br d, 2H, poly-CH2O),
3.09–1.04 (br peaks, 7H, aliphatic ring protons).
Polymer 23: 0.316 g (73%). IR (cm–1): 1712 (CO), 967
1
(trans olefin). H NMR (200 MHz, CDCl3): δ (ppm): 8.00–
7.80 (br s, 2H, ArH), 7.40–6.75 (br s, 11H, ArH), 5.45–5.25
(br s, 2H, olefinic H), 4.35–4.05 (br d, 2H, poly-CH2O),
3.00–0.90 (br peaks, 7H, aliphatic ring protons).
Polymer 24: 0.186 g (66%). IR (cm–1): 1714 (CO), 964
1
(trans olefin). H NMR (200 MHz, CDCl3): δ (ppm): 8.00–
7.85 (br s, 2H, ArH), 7.35–6.75 (br s, 19H, ArH), 5.45–5.20
(br s, 2H, olefinic H), 4.40–4.10 (br s, 2H, poly-CH2O),
3.00–0.90 (br peaks, 7H, aliphatic ring protons).
26. S.T. Nguyen and R.H. Grubbs. J. Am. Chem. Soc. 115, 9858
(1993).
27. S. Kanaoka and R.H. Grubbs. Macromolecules, 28, 4707
(1995).
Acknow ledgements
28. C. Fraser and R.H. Grubbs. Macromolecules, 28, 7248 (1995).
29. P. Schwab, M.B. France, J.W. Ziller, and R.H. Grubbs. Angew.
Chem. Int. Ed. Engl. 34, 2039 (1995).
30. D.M. Lynn, S. Kanaoka, and R.H. Grubbs. J. Am. Chem. Soc.
118, 784 (1996).
31. M. Weck, P. Schwab, and R.H. Grubbs. Macromolecules, 29,
1789 (1996).
32. P. Schwab, R.H. Grubbs, and J.W. Ziller. J. Am. Chem. Soc.
118, 100 (1996).
Financial support for this work provided by the Natural
Sciences and Engineering Research Council of Canada
(NSERC), American Chemical Society – Petroleum Re-
search Funds (ACS–PRF), and Manitoba Hydro is gratefully
acknowledged. A.L.E. and K.M.E. (graduate students, Uni-
versity of Manitoba) also thank the Department of Chemis-
try at the University of Manitoba. Mettler Toledo is also
gratefully acknowledged.
33. M. Weck, B. Mohr, B.R. Maughon, and R.H. Grubbs. Macro-
molecules, 30, 6430 (1997).
34. D.M. Lynn, B. Mohr, and R.H. Grubbs. J. Am. Chem. Soc.
120, 1627 (1998).
35. E.L. Dias and R.H. Grubbs. Organometallics, 17, 2758 (1998).
36. T. Weskamp, W.C. Schattenmann, M. Spiegler, and W.A.
Hermann. Angew. Chem. Int. Ed. Engl. 37, 2490 (1998).
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38. H. Katayama and F. Ozawa. Chem. Lett. 67 (1998).
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40. R.R. Schrock, J. Feldman, L.F. Cannizzo, and R.H. Grubbs.
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