Methanolysis of organophosphorus esters promoted by an M2+ catalyst supported on polystyrene-based copolymers

Article abstract of DOI:10.1139/V07-099

The methanolysis of three neutral organophosphorus esters (a phosphonate, a phosphonothioate, and a phosphorothionate) promoted by several polymer-supported Zn(II) or Cu(II) containing catalysts was studied. The catalysts consist of a Zn(II) or Cu(II) complex with 1,5,9-triazacyclododecane or phenanthroline attached to a porous polystyrene resin. In each case, the polymer supported catalyst showed activity at near neutral _s ^spH in methanol (8.38) and ambient temperature and provided accelerations of up to a factor of 2.9 × 10⁶ relative to the background reaction at _s^spH 9.05. The solid materials could be reused several times and could be reactivated when the activity diminished. Various polymers of different porosity and extent of cross-linking were studied, with the net result being that larger porosities offer the best reactivity for catalyzed methanolysis of these OP species in methanol. This is explained by different parameters including the accessibility to reactive sites, the increase of concentration of catalytic sites on the surface of the polymer, and some cooperative effects between neighboring catalytic groups.

Full text of DOI:10.1139/V07-099

9
1
Methanolysis of organophosphorus esters
2+
promoted by an M catalyst supported on
polystyrene-based copolymers
Benoit Didier, Mark F. Mohamed, Elizabeth Csaszar, Kate G. Colizza,
Alexei A. Neverov and R. Stan Brown
Abstract: The methanolysis of three neutral organophosphorus esters (a phosphonate, a phosphonothioate, and a
phosphorothionate) promoted by several polymer-supported Zn(II) or Cu(II) containing catalysts was studied. The cata-
lysts consist of a Zn(II) or Cu(II) complex with 1,5,9-triazacyclododecane or phenanthroline attached to a porous poly-
s
styrene resin. In each case, the polymer supported catalyst showed activity at near neutral pH in methanol (8.38) and
s
6
ambient temperature and provided accelerations of up to a factor of 2.9 × 10 relative to the background reaction at
s
s
pH 9.05. The solid materials could be reused several times and could be reactivated when the activity diminished.
Various polymers of different porosity and extent of cross-linking were studied, with the net result being that larger po-
rosities offer the best reactivity for catalyzed methanolysis of these OP species in methanol. This is explained by dif-
ferent parameters including the accessibility to reactive sites, the increase of concentration of catalytic sites on the
surface of the polymer, and some cooperative effects between neighboring catalytic groups.
Key words: functionalized polymer, metal containing, methanolysis, organophosphorus pesticides and CW agents,
catalyst.
Résumé : La méthanolyse de trois esters organophosphorés neutres (un phosphate, un phosphonothioate et un phospho-
rothionate) ont été étudié en présence de plusieurs catalyseurs contenant du Zn(II) et du Cu(II) compléxés avec du
1
,5,9-triazacyclododécane ou de la phénantroline supportés par des matrices polymères poreuses. Dans chacun des cas,
s
le catalyseur supporté par le polymère est actif à température ambiante et à pH proche de la neutralité dans le métha-
nol (8,38) en fournissant des accélérations allant jusqu’à 2,9 x 10 par rapport aux vitesses de réaction obtenues en
l’absence de catalyseur métallique à un pH de 9,05. Les matériaux utilisés peuvent être réutilisés plusieurs fois ou
s
6
s
s
réactivés lorsque leur activité diminue. Divers matrices polymères de porosité et de degrés de réticulation différents ont
été étudiés et il a été observé que les catalyseurs fixés sur les matrices ayant la porosité la plus large ont la plus forte
activité catalytique pour la méthanolyse de ces esters phosphoriques dans le méthanol. Ce résultat s’explique par divers
paramètres, incluant l’accessibilité des sites réactifs, l’augmentation de la concentration des sites catalytiques à la sur-
face du polymère et de quelques effets de synergie entre des espèces catalytiques voisines.
Mots-clés : polymère fonctionnalisé contenant un métal, méthanolyse, pesticides organophosphorés, gaz de combat,
catalyse.
[
Traduit par la Rédaction Didier et al. 100
Introduction
cides, and acaricides (3). Among the most nefarious of the
CW agents are the phosphonothioate esters that are V-agents,
such as VX (1) and Russian VX (2) and the phosphono-
flouridate G-agents such as soman (3) and sarin (4). Other
kinds of OP esters, such as the phosphate triesters and
phosphorothionate esters (5, 6), are used as pesticides.
Neutral organophosphorus (OP) compounds with leaving
groups having pK values less than 8 comprise a very toxic
family of compounds that inhibit acetylcholinesterase (1, 2)
and thus have uses as chemical warfare (CW) agents, pesti-
a
Due to the noxious nature of these materials and the fact
that some of them linger in the environment, methods for the
decomposition and decontamination of these are continually
sought (4). Only a few methods employ metal ions, but gen-
erally these are not very effective in water for hydrolysis be-
cause of substrate and metal ion solubility problems and also
the inherent low activity of the metal ions in promoting
solvolysis, which has yet to be overcome in aqueous media.
In practice, a decomposition method should be inexpensive,
have a high reaction rate, occur at neutral pH and ambient
temperature, and convert the toxic starting material into far
less toxic or nontoxic products.
Received 15 June 2007. Accepted 30 July 2007. Published on
the NRC Research Press Web site at canjchem.nrc.ca on
2
0 September 2007.
This article is dedicated to the memory of Professor Keith
Yates.
B. Didier, M.F. Mohamed, E. Csaszar, K.G. Colizza,
1
A.A. Neverov, and R.S. Brown. Department of Chemistry,
Queen’s University, Kingston, ON K7L 3N6, Canada.
1Corresponding author (e-mail: rsbrown@chem.queensu.ca).
Can. J. Chem. 86: 91–100 (2008)
doi:10.1139/V07-099
© 2007 NRC Canada

9
2
Can. J. Chem. Vol. 86, 2008
Recent work in our laboratories indicates that neutral (un-
charged) esters of phosphates and phosphorothioates (5a,
In some cases, affixing the catalytic group to a solid sup-
port can be expected to confer particular advantages of effi-
ciency and cost effectiveness that come from being able to
recover and reuse the catalyst. There are several reported
studies of the hydrolytic decomposition of organophos-
phorus compounds promoted by solid supported M(II)-
containing catalysts (9–12). In several cases the reactivity of
the polymer supported catalyst decreases considerably com-
pared with the activity in solution because of surface and
diffusion effects, but in other cases the activity was still ac-
ceptable, particularly when the polarity of polymeric matrix
was changed (10b, 10c), the coordination sphere of catalytic
complex was modified (10c), or a linker was introduced be-
tween matrix and catalytic system (9). Nevertheless, all the
prior reported studies concentrated on hydrolytic systems
where the expected OP products would be acids that may
present problems, such as inhibiting the activity of the M(II)
through binding of the ionized anionic phosphate or
phosphonate. In some cases, such as with the hydrolysis of
V-agents, some of the hydrolytic products arise through
cleavage of the P-OEt linkage, giving a product that is just
as toxic as the starting materials but far more resistant to hy-
drolysis (1, 2).
5
b), phosphonates (5c), and phosphonothioates (5d) are rap-
3
+
idly solvolyzed in methanol solution in the presence of La
or a Zn(II)-complex of 1,5,9-triazacyclododecane (7a),
forming nontoxic methyl esters. In addition, we have found
–
–
that the corresponding Cu(II)( OCH ) or Zn(II)( OCH )
3
3
complexes of 7a (6, 7) and 8 (7) catalyze the methanolysis
of phosphate triesters and phosphorothionate triesters with a
particular propensity for the latter. Routinely we find that a
1
mmol/L solution of the metal species gives accelerations
8
9
of the methanolysis of these materials by factors of 10 –10
over the background reactions at neutral pH and ambient
s
s
temperature (8). All these exhibit true catalytic turnover, and
all seem to function according to the simple kinetic scheme
given in eq. [1]. The disadvantage of complex with 8 is the
formation of dimers that are inactive, so it seemed reason-
able that fixing the ligands on a solid support could form ex-
clusively monomeric catalysts and prevent the formation of
inactive species.
O
O
X
P
RO
P
S
NR'
2
RO
P
F
RO
OAr
Me
Me
OR'
Herein we report on the synthesis and analysis of some
divinylbenzene (DVB) cross-linked meso- and macro-porous
polystyrene resins functionalized with 7a, 7b, or 5-amino-
1
; R=Et, R'=CH(CH
3
)
2
3; R=CH(CH
3
)(C(CH
3
)
3
)
5; X=O, R, R'=alkyl, aryl
6; X=S, R, R' = alkyl, aryl
2
; R=CH CH(CH ) , R'=Et
2
3 2
4; R=CH(CH )
3 2
1
,10-phenanthroline (5-NH -8). After loading the resins with
2
2
+
2+
2+
an M ion (Cu or Zn ), the catalytic activity was deter-
mined for the methanolysis of three different OP compounds
proposed as simulants for the G-agents (O-ethyl-O-4-
nitrophenyl methylphosphonate (9)), the V-agents, (3,5-O-
ethyl-S-3,5-dichlorophenyl methylphosphonothioate (10)),
Kb
+
+
[
1]
Substrate + Mx (-OR)
Substrate:Mx (-OR)
ꢀ
+
kcat
+
Substrate + Mx (-OR)   → Substrate:Mx (-OR)
®
and for phosphorothionate pesticides (fenitrothion (11)).
H
H
Experimental
N
N
N
N
Materials
N
H
N
Methanol (99.8% anhydr.), DMF (99.8%), sodium
methoxide (0.5 mol/L solution in methanol), Cu(CF SO ) ,
3
3 2
7
b
7
a
Zn(CF SO ) , 1,5,9-triazacyclododecane, styrene, 4-
3
3 2
(
chloromethyl)styrene, divinylbenzene, benzoyl peroxide,
H
boric acid, and sodium hydroxide were purchased from
Sigma-Aldrich and used as supplied. THF (extra dry, with
N
N
molecular sieves, water < 50 ppm) and HClO (70% aq. so-
4
N
N
N
lution) was purchased from Acros Organics and used with-
out further purification. Cellosize, xantham gum, and 5%
Pd/C catalyst were purchased from Fluka and n-pentanol
was purchased from BDH Chemical; these were used as sup-
plied. Merrifield’s polymer resin mesoporous (Meso-Ald)
H
8
7
c
Cl
Cl
O
O
(
2% crosslinked with DVB, 0.6–0.8 mmol Cl/g, 200–400
EtO P O
Me
NO2
EtO P S
Me
mesh) and macroporous (Macro-Ald) (1.2 mmol Cl/g, 100–
200 mesh) were purchased from Sigma-Aldrich. PL-CMS
MP resin (Macro-PL) (>12% of cross-linking with DVB,
9
10
2
.8 mmol Cl/g, porosity size 100 Å, particle size 150–
S
300 µm) was purchased from Polymer Laboratories.
Fenitrothion (11, O,O-dimethyl O-(3-methyl-4-nitrophenyl)
phosphorothioate), was a gift from Professors Erwin Buncel
and Gary van Loon of this department. O-Ethyl-S-3,5-
dichlorophenylmethylphosphonothioate (10) and O-ethyl-O-
MeO P O
OMe
NO2
1
1
4
-nitrophenylmethylphosphonate (9) were synthesized as re-
ported previously (5e, 5d).
©
2007 NRC Canada

Didier et al.
93
Suspension polymerization syntheses of macroporous
resins (DVB20, DVB50, and DVB50-hl).
N-benzyl-1,5,9-triazacyclododecane
The title compound was made as described in ref. 16.
The following procedure was based on the work of Durie
et al. (13). An aqueous phase was prepared by dissolving
Modification of polymeric resins with 7a or 7b
0
.087 g of xantham gum, 0.012 g of Cellosize, and 1.73 g of
Commercial Macro-Ald resin (0.50 g, 0.6 mmol of Cl, 1
equiv.) was swelled in 10 mL of THF for 1 h. 1,5,9-
Triazacyclododecane (7a) (0.12 g, 0.7 mmol, 1.15 equiv.)
was added and the mixture was heated at reflux and stirred
carefully overnight. The polymer was recovered by filtration
and washed with THF (3 × 10 mL) and dried in oven at
boric acid in 100 mL of water. This mixture was vigorously
stirred to obtain a cloudy solution. Using 20% divinyl-
benzene cross-linker as an example to make DVB20, the
monomer mixture comprised DVB (~80% grade) (1.50 mL,
~
20 wt% actual DVB as compared with the other mono-
mers), styrene (4.33 mL), and 4-(chloromethyl)styrene
0.59 mL, ~10% molar ratio with styrene), to which was
added benzoyl peroxide (0.080 g) and n-pentanol (4.22 mL,
40 vol% of the entire organic phase). The combined or-
6
0 °C for 24 h.
(
The modification with the immediate precursor of 7a,
triazatricyclo[7.3.1.0]tridecane (7b), was done by the same
procedure using the same molar ratios, after which the re-
covered polymer was subjected to hydrolysis using a solu-
tion of 10 mL each of ethanol and water containing 1.07 g
of sodium hydroxide heated at reflux overnight to liberate
the 1,5,9-triazacyclododecane-functionalized resin. In all
cases the final polymer functionalized with 7a was subse-
quently treated with a solution of THF–methanol (50:50 v/v,
~
ganic phase was added dropwise into the aqueous phase with
vigorous stirring. The suspension was then stirred at 80 °C
for six hours, cooled, and the polymeric beads were col-
lected by filtration and washed with water (50 mL). The ma-
terial was washed with methanol (50 mL) and then acetone
(
50 mL). The yield of polymeric beads was 60% after drying
in an oven at 60 °C for 24 h.
2
0 mL) containing 200 µL of sodium methoxide (0.5 mol/L)
for 15 h to remove all traces of acid and residual exposed
chloromethyl functionality.
Characterization of porosity
To characterize the porosity of the beads, we followed a
procedure reported by Chemin et al. (14) where the volume
of porosity and the accessible porous volume for methanol
were characterized by a measurement of the apparent den-
sity of the polymeric beads in different solvents. Around 2 g
of dry polymeric beads were weighed in a tared 50 mL volu-
metric flask, after which 40 mL of solvent were introduced.
For the measurement with hexane, the flask was placed in an
ultrasonic bath for 10 min, after which the mixture was al-
lowed to stand for 2 h at room temperature. The volume was
adjusted with hexane and the flask was weighed again. This
procedure gives an apparent volumetric weight of beads in
the given solvent (e.g., hexane, water, and methanol) by us-
ing the following formula:
Modification of polymeric resins with 5-amino-1,10-
phenanthroline
Polymer-bound phenanthroline was prepared via a modifi-
cation of a published route (15). Commercial PL-CMS MP
resin (0.824 g, 2.31 mmol of Cl, 1 equiv.) and solid 5-
amino-1,10-phenanthroline (0.724 g, 3.71 mmol, 1.6 equiv.)
were added to a 100 mL round-bottomed flask equipped
with a reflux condenser and a small magnetic stirbar. To the
flask was added 50 mL of anhydrous DMF and the mixture
was gently stirred, to avoid crushing of the polymer, and
heated to reflux. After 1 h of heating, triethylamine (520 µL,
3.7 mmol) was added to the reaction mixture and the mix-
ture was allowed to continue refluxing. An additional
2
30 µL (1.65 mmol) of triethylamine was added after 24 h of
Wp
heating and the two phase mixture was left to reflux for an-
other 48 h. After cooling, the polymer was filtered and
washed with 20 mL of DMF and 100 mL of methanol. The
resin was left to stir gently in boiling DMF for three hours
followed by filtration and rinsing with methanol. To remove
residual DMF, the polymer was boiled in acetone at 60 °C
overnight, collected, filtered, and washed with acetone and
then methanol. The functionalized polymer was treated with
a 20 mL solution of sodium methoxide (5 mmol/L) in meth-
anol for 15 h to remove any traces of acid and residual ex-
posed chloromethyl functionality.
s
[
2]
ρ a =
1
1
00 −(W −W )×
2 1
ρs
where W is the weight of polymer in g, W is weight of the
flask with beads, W is the weight of the flask with the beads
p
1
2
s
filled with the solvent, ρ is the density of the solvent, and ρ
s
a
is the apparent density of the beads in the solvent (in g/mL).
The pore volume (P%) or the accessible porous volume in
methanol was calculated with the following equation:
w





ρ
a

[
3]
P(%) = 1−
×100
Metal complexation of polymer bound ligand
s


ρ a
A 0.1 mol/L solution of M(OTf) was prepared in metha-
2
nol and the polymer was immersed in this solution for 4 h
after which it was separated by filtration, washed with meth-
anol, and dried in oven at 60 °C for 24 h. A final step placed
the material into a basic methanol solution (20 mL of metha-
w
where ρ is the apparent density of the beads in water
a
s
in g/mL, and ρ is the apparent density of the beads in hex-
ane for total pore volume or in methanol for accessible po-
rous volume in methanol.
a
nol with 200 µL of 0.5 mol/L sodium methoxide) to obtain
–
the active catalytic species of complexed M(II):( OCH ).
3
5
-Amino-1,10-phenanthroline
-Amino-1,10-phenanthroline was prepared via a modifi-
cation of a previously published route (15).
5
Analysis of the M(II) loading
The metal-loaded polymer (around 0.01 g) was immersed
©
2007 NRC Canada

9
4
Can. J. Chem. Vol. 86, 2008
Table 1. Characteristics of functionalized polystyrene resins synthesized and complexed with Copper (II).
Total pore
Pore volume access
Name
Triaza-precursor
Cla
M(II)b
volume (mL/g)c
CH OH (mL/g)
c
3
DVB20
DVB50
7b
7b
7a
7b
7a
7a
7b
0.7
0.7
3.9
2.8
2.8
1.2
0.7
0.009 (Cu)
0.033 (Cu)
0.4 (0.1)
0.6 (0.1)
NA
0.27 (0.02)
0.49 (0.03)
NA
d
d
DVB50-hl
Macro-PL
Macro-PL-(II)
Macro-Ald
Meso-Ald
a
0.09 (Cu), 0.11 (Zn)
0.13 (Cu)
0.23 (Cu), 0.14 (Zn)
0.15 (Cu), 0.02 (Zn)
0.014 (Cu)
0.8 (0.1)
0.8 (0.1)
0.8 (0.1)
0.48 (0.05)
0.48 (0.05)
0.31 (0.05)
d
d
NA
NA
Chlorine loading in mmol/g.
Metal ion loading in mmol/g.
Error limits given in brackets.
b
c
d
NA = not available.
in 2 mL of nitric acid solution in methanol (5% v/v) for
0 min. The methanol solution was carefully decanted away
ties, which include chemical inertness, structural stability
that enables a controllable porosity that ensures accessibility
of reagents to the internal catalytic domains, and the ClCH2-
functionalities that can be modified to attach various
catalytic systems to the matrix. Three different commercial
polymers were used in this study, one mesoporous (Meso-
Ald) and two macroporous (Macro-Ald and Macro-PL).
Macro-PL is defined by its manufacturer as macroporous but
has an average size porosity of 10 nm and does not corre-
spond to the IUPAC definition (18) that distinguishes three
porous domains: microporosity (<2 nm), mesoporosity (2–
3
from the polymer, reserved, and the acid wash was repeated
with this material four times. The combined methanol
washes were stripped of solvent to produce ~0.2 mL of a
residue, which was diluted with water in a volumetric flask
2
+
(
25 or 50 mL). The concentration of M in this solution was
obtained by atomic absorption spectrometry using a Varian
Spectra AA-20 Plus spectrometer. The spectrometer was cal-
2
+
ibrated with known [M ] solutions (0.5–5 ppm for copper,
and 0.1–0.5 ppm for zinc).
5
0 nm), and macroporosity >50 nm).
Kinetics
Three other polystyrene resins were synthesized in this
All kinetics experiments with the polymers were con-
ducted in 2.5 mL of a methanol solution buffered with N-
work by radical suspension polymerization wherein a mix-
ture of monomer and a radical precursor (benzoyl peroxide)
was dissolved in a solvent and was finely dispersed in an
aqueous phase. Three different monomers in varying propor-
tions were used, styrene and 4-(chloromethyl)styrene to en-
sure the reactive function of polymer and divinylbenzene to
obtain cross-linking of the polymeric matrix. The solvent
iso-propylmorpholine (6.8 × 10–3 mol/L) at pH = 9.0 ± 0.4.
s
s
The rates of methanolysis of 9 and 11 (0.03 mmol/L) cata-
lyzed by heterogeneous M(II)-7 complex (0.08 g to 0.75 g;
–
3
–3
1
× 10 mol/L < [M(II)-7] < 30 × 10 mol/L suspended in
the buffered methanol) were followed by monitoring the ap-
pearance of p-nitrophenol (or 3-methyl-4-nitrophenol) at
(
pentanol) containing the monomeric phase was used as the
3
12 nm or the disappearance of starting material at 264 nm,
porogen (17, 19) because it is known to permit a large po-
rosity (19, 20). During the polymerization process, a phase
separation occurs between the growing polymeric chain and
the porogenic agent, and the matrix forms around the space
where the solvent is occluded creating the porous structure.
Two polymers were synthesized, one (DVB20) with 20 wt%
of divinylbenzene and another (DVB50) with 50 wt%. In all
cases the porogen was introduced to make up 40% of the
volume of the organic phase. A third matrix was prepared
with the same amount of DVB as for DVB50 but with only
using a Cary 100 UV–vis spectrophotometer with the cell
compartment thermostatted at 25.0 ± 0.1 °C. The rates of
methanolysis of 10 (0.3 mmol/L) were followed by monitor-
ing its disappearance at 253 nm.
Kinetic experiments with the Zn(II) complex of N-benzyl-
1
,5,9-triazacyclododecane (7c/Zn(II)) were conducted in
methanol under self-buffered conditions where the ligand,
Zn(OTf) , and NaOCH were formulated in stock solutions
2
3
s
s
in a 1:1:0.5 molar ratio ( pH = 10). The kinetics of the
methanolysis of phenyl acetate (1.0 × 10 mol/L) and 9
–
4
4
-(chloromethyl)styrene as the other monomer, to obtain a
polymer with high loading (designated as DVB50-hl).
–
5
(
3.6 × 10 mol/L) were monitored at 280 and 320 nm, re-
spectively, as a function of [7c/Zn(II)]total. The k value for
the catalyzed methanolysis was determined as twice the gra-
dient of the kobs vs. [7c/Zn(II)]total plot, the factor of two be-
ing introduced because the active form is [7c/Zn(II): OCH ],
which is present at 1/2 the concentration of the total Zn(II)
complex.
2
The porosities of the resins were characterized by measur-
ing their apparent densities in different solvents (hexane,
water, and methanol). From those values one calculates,
from eqs. [2] and [ 3], the volume of total porosity and po-
rous volume accessible to methanol (14). Data are reported
in Table 1. The results show slightly higher pore volumes for
the commercial polymers than for the synthesized polymers.
However, the ratio of this volume to that accessible to meth-
anol is 70%–80% for prepared polymers and somewhat less
for the commercial polymers, ~60% for Macro-PL and
~40% for Macro-Ald. This result shows that a majority of
pores are not accessible to methanol in Macro-Ald. For
–
3
Results and discussion
Functionalized polymer preparation
The chloromethylated polystyrene support matrix was
chosen for its desirable (17) physical and chemical proper-
©
2007 NRC Canada

Didier et al.
95
2
+
Table 2. Apparent second-order rate constants of the complex 8/Zn in solution and of different
2
+
s
polymer resins functionalized with 8/Zn , determined at pH = 9 in methanol, buffered with N-
s
–
4
–5
iso-propylmorpholine, T = 25 °C, [10] = 3 × 10 mol/L, and [9] = [11] = 3 × 10 mol/L.
M(II)– loading
(mmol/g)
k2 (10)
((mol/L) s )
k2 (9)
((mol/L) s )
–
1 –1
–1 –1
Polymer
DVB50-hl 8/Zn2
+
0.065
0.035
0.098
0.31
0.80
0.61
0.49
1.17
11.75
Macro-PL 8/Zn2
+
Macro-PL-(II) 8/Zn2
+
Note: Error limits considered to be ±20%, based on the errors in the determination of metal loading and un-
certainties in the duplicate rate measurements.
Fig. 1. Scheme of the modification of polystyrene resins.
vent methanol, it is possible that some of the ligand sites
could not be accessed, which could also contribute to the
1
) 7a or 7b
2
+
Cl 2) NaOH in H
2
O/EtOH
L
relatively low amount of Cu on the polymer. In fact, we
have chosen to do the metallation under nonswelling condi-
tions as this is the medium where all the subsequent cata-
lytic reactions are performed, and the metal ion loading was
determined under non-swelling conditions in aqueous acid.
Another possibility for some materials is a difference in re-
activity of 7a and its precursor 7b, since it is generally ob-
served that materials prepared with the latter always have a
NH
2
or
N
N
M(OTf)
2
NH
N
H
L
=
or
N
HN
N
N
2
+
slightly lower Cu loading. Indeed, the only difference be-
tween Macro-PL and Macro-PL-(II), where the polymeric
matrix is the same for each, is the triazacyclododecane pre-
cursor, which is 7b for Macro-PL and 7a for Macro-PL-(II).
It could be that there is a higher reactivity with the more
flexible 7a relative to 7b or that the hydrolysis step required
for the latter in ethanol–water is not very efficient because
of the low affinity between polystyrene resin and this sol-
vent mixture. As a final note, we observed that the polymers
prepared for this study have much lower conversion of chlo-
ride into the Cu -loaded resin (<3%) relative to the com-
mercial resins. This is possibly due to the high level of
cross-linking, since it is known (21) that a higher level de-
creases the reactivity of functional groups on a rigid poly-
meric backbone.
The modification of polymeric resins with 5-amino-1,10-
phenanthroline was done following a published procedure
(15). The loading of zinc after this modification was low
(see Table 2) with 0.035 mmol/g compared with
0.14 mmol/g for zinc loading to Macro-PL-(II)
functionalized with 7a. Subsequently we changed the
functionalizing solvent to DMF, in which the 5-amino-1,10-
phenanthroline is more soluble than in dioxane. The solvent
change increased the loading about three-fold, giving a load-
ing of ~0.1 mmol/g, which is close to that found with 7a.
(
II)M-:L
Macro-PL, the advertised pore size is 10 nm but the porosity
for Macro-Ald, although not specified, seems to be smaller
according to the criteria here.
All the polymeric matrices were functionalized by nucleo-
philic substitution of the benzylic chloride by 1,5,9-triaza-
cyclododecane (7a) or its immediate precursor
triazatricyclo[7.3.1.0]tridecane (7b) as shown in Fig. 1.
Using 7b, the polymer must then be subjected to base cat-
alyzed hydrolysis with sodium hydroxide in water–ethanol,
to obtain the 1,5,9-triazacyclododecane functionalized poly-
mer. Once functionalized, all the polymers are treated with a
sodium methoxide THF–methanol solution to deprotonate
the highly basic triazacyclododecane and to react with any
residual benzylic chloride that might affect the future char-
acteristics of the material. The subsequent steps involve the
loading (Cu or Zn ), wherein the polymeric matrix
was immersed in an 0.1 mol/L M(OTf) solution in metha-
nol. In the case of copper, the loading is visually character-
ized for the 7a functionalized polymer by an immediate
green-blue colouring of the solid, which remained so after a
final washing with methanol.
The M loading was quantified by immersing a known
quantity of the resin in a known volume of a 5% solution of
nitric acid in methanol, which protonates the ligand and re-
leases metal ion into the solution, as judged by the loss of
colour of the solid in the case of copper. The solution was
then analyzed by atomic absorption spectroscopy and the re-
sults are presented in Table 1. The data show that, in all
cases, there is an incomplete conversion of chloride into
metal complex. The best result was obtained with Macro-
Ald with a conversion of 13% of the available chloride. The
low conversion likely stems from the fact that some of the
Cl is buried inside the polymer in sites inaccessible to the
triaza ligand although the functionalization was done in
THF, which is known to swell polystyrene appreciably.
Since the metallation step was done in the nonswelling sol-
2
+
2
+
2+
2+
M
2
2
+
Catalytic studies
Study of the catalytic activity of the materials was conducted
by determining the rate of change in the UV–vis absorbance
for loss of substrate and formation of product in methanol
solutions containing known amounts of the solid resins. Poly-
mer (0.05 g to 0.75 g) was put into 2.5 mL of methanol solu-
–
3
tion buffered by N-iso-propylmorpholine (6.8 × 10 mol/L)
s
s
at pH ~ 9 (the range of pH values is between 8.6 and 9.8)
s
s
s
(22), which is slightly above neutrality ( pH = 8.4 (22)). For
s
practical reasons owing to the high absorptivities of the tur-
bid media, the heterogeneous mixtures were not stirred con-
tinuously; rather, the cell was shaken every 2 to 5 min and
the particles were allowed to settle prior to measurement of
©
2007 NRC Canada

9
6
Can. J. Chem. Vol. 86, 2008
Table 3. Apparent second-order rate constants of the complex 7a/M in solution and of
2
+
2
+
s
different polymer resins functionalized with 7a/M , determined at pH = 9 in methanol,
s
–
4
buffered with N-iso-propylmorpholine, T = 25 °C, [10] = 3 × 10 mol/L, and [9] = [11] =
3
× 10–5 mol/L.
k2 (10)
((mol/L) s )
k2 (9)
((mol/L) s )
k2 (11)
((mol/L) s )
–
1 –1
–1 –1
–1 –1
Catalyst
–OCH
7
2.17a
—
3
3.1
—
0.47
—
0.21
0.17
95.2
0.95
0.38
0.2
2.7b
243b
0.18
0.07
0.17
0.02
0.14
0.017
0.005
46.8
–4 b
(7.2±0.2)x10
12.2
3
+ c
a/Cu2
DVB20 7a/Cu
DVB50 7a/Cu2
b
2
+
+
0.05
0.02
0.04
0.005
0.05
0.006
0.0003
—
2
+
DVB50-hl 7a/Cu
Macro-PL 7a/Cu2
+
2
+
Macro-PL-(II) 7a/Cu
Macro-Ald 7a/Cu
2
+
2
+
Meso-Ald 7a/Cu
+ d
7
a/Zn2
2
+
DVB50-hl 7a/Zn
Macro-PL-(II) 7a/Zn
Macro-Ald 7a/Zn2
0.33
0.09
0.015
—
—
—
2
+
+
Note: Error limits considered to be ±20%, based on the errors in the determination of metal loading
and uncertainties in the duplicate rate measurements.
a
Ref. 7.
Ref. 5c.
b
c
2+
M
complex of 1,5,9-triazacyclododecane in methanol.
d
Ref. 5d.
the absorbance. In an attempt to quantify the amount of M2+
in the solution, the known amount of the heterogeneous
resin was converted to concentrations as if it were com-
pletely dissolved (this is termed [bound M ]). Under this
assumption, the metal concentration varied between 1 and
Table 4. Dependence of the pseudo first-order rate
constants for the disappearance of 9 (0.03 mmol/L)
and appearance of p-nitrophenol mediated by 0.32 g
2
+
2+
of Macro-PL-(II) 8/Zn on the frequency of
kobs for the
3
0 mmol/L, while those of the substrates were 0.3 mmol/L
Frequency
of shaking
kobs for the
loss of 9 (s )
appearance of
p-nitrophenol (s )
for 10 and 0.03 mmol/L for 9 and 11. Under these condi-
tions, the change in absorbance followed good first-order be-
haviour, and the pseudo first-order rate constants, kobs, were
evaluated by fitting the Abs. vs. time curves to a standard
exponential model. The apparent second-order rate constants
–
1
–1
3
60 s
120 s
0 s
0.011
0.009
0.007
0.0045
0.0038
0.0032
2
+
were evaluated as kobs/[bound M ] and are given in Table 3
for material with 7a/M2 and in Table 2 for 8/Zn . Control
experiments showed that in all but one case the rate constant
obtained did not depend upon the frequency of shaking the
mixture. This suggests that for these cases the overall cata-
lytic process is not limited by transport through solution, al-
though it might be limited by transport through the polymer
or across the phase boundaries. On the other hand, we do
have one case where there is a dependence of the reaction
rate on the frequency of shaking for methanolysis of 9 in the
presence of a relatively large amount (0.32 g) of Macro-PL-
+
2+
with 5.2 mg of Macro-PL-(II) 7a/Cu2+ in 2.5 mL of methanol
solution buffered by N-iso-propylmorpholine (6.8 mmol/L) at
pH = 8.8 in presence of 9 at 1 mmol/L. In that case, the
s
s
pseudo concentration of copper was 0.48 mmol/L and the
Abs vs. time curve showed a complete loss of starting mate-
–1
rial with a kobs value of 0.0083 min , which corresponds to
–1 –1
a second order rate constant of 0.28 (mol/L) s .
In the cases of the commercial macroporous polymers,
and most prominently with Macro-Ald functionalized with
2
+
(
II) 8/Zn . The kinetic results for the rate of disappearance
2+
2+
7
a/Cu and 7a/Zn , a less than expected amount of product
s
of 9 and appearance of p-nitrophenol at pH = 8.52
s
phenol was observed during the reaction of 9 and 11, along
with a complete disappearance of starting material, although
analysis of the Abs vs. time curves for each gave the same
value of kobs. This suggests that the starting material is at
equilibrium with respect to partitioning into the polymer and
the rate-limiting step is the chemical one of cleavage, but the
product partitions between the solution and the polymer
phase.
(
6.5 mmol/L N-isopropyl morpholine) shown in Table 4 in-
dicate that the rate constants for each process increase with
the frequency of shaking, although in all cases the rate for
liberation of product is slower by roughly a factor of two
than the rate of disappearance of 9. This is consistent with a
process where the reaction rate is partially limited by the
diffusion of the substrate into the polymer and more so by
the chemical step of methanolysis to form p-nitrophenol and
Where comparisons can be made, and using the pseudo
M2 concentrations for the catalysts as described earlier,
none of the functionalized polymers have second-order rate
+
(
or) its diffusion out of the polymer.
To demonstrate that the polymers are truly catalytically
active, an experiment with an excess of substrate was done
2
+
constants approaching those of the free 7a/M catalysts in
©
2007 NRC Canada

Didier et al.
97
solution. This is a commonly observed phenomenon with
polymeric catalysts and probably stems from a diminution of
mobility in the solid catalytic systems, which impedes diffu-
sion of substrate to the reactive sites. It is also possible that
since the polymer supports described here require N-
benzylated 1,5,9-triazacyclododecanes, that these are far
Fig. 2. Pseudo first-order rate constant, kobs, for the methanolysis
2
+
2+
of 9 mediated by 7a/Cu (ᮀ) and 7a/Zn (Ž) functionalized
s
Macro-PL-(II) vs. weight of the polymer at s pH = 8.7, T =
25 °C.
2
+
more sterically hindered than 7a/M . Indeed, a recent report
0
0
0
0
.15
.10
.05
.00
(
23) indicates that the methanolysis of the carboxylate ester
–
phenyl acetate promoted by 7c/Zn(II): OCH proceeds with
a second-order rate constant of 0.046 (mol/L) s , which is
fully 300 times slower than what is reported for the
methanolysis of phenyl acetate by 7a/Zn(II): OCH (13.9
3
–
1 –1
–
3
–
1 –1
(
mol/L) s (24)). Our own repetition of the catalysis of
–
methanolysis of phenyl acetate promoted by 7c/Zn(II):
OCH indicates that the second-order rate constant is 4.0 ±
3
–
1 –1
0
.2 (mol/L) s , which is only a factor of three less than
–
that reported for 7a/Zn(II): OCH , which suggests that there
3
is some anomalous error in the recently reported value (23).
A similarly small steric effect of 2.5 fold is also evident in
the second-order rate constant for the methanolysis of 9 ex-
hibited by 7c/Zn(II): OCH (18.2 ± 0.2 (mol/L) s ) relative
to that of 7a/Zn(II): OCH (46.8 ± 0.5 (mol/L) s (5c).
0.03
0.08
0.13
0.18
Weight (g)
–
–1 –1
3
–
–1 –1
3
2
+
with the same 8/Zn -grafted polymer, the appearance of
phenol in the solution is more pronounced. Control experi-
ments establish that the absorbance of a solution of p-
nitrophenol decreases in the presence of fresh polymer
functionalized with 8/Zn . These observations confirm that
phenol does partition between the polymer and solution, but
that after several reactions the polymer eventually becomes
saturated with the product.
It therefore seems reasonable to ascribe the reduced activ-
ity of these functionalized polymers relative to the solution
catalysts to surface effects with the polymers that impeded
the mobility of the substrate in reaching the active sites.
Nevertheless, the catalysts supported on these resins do ac-
2
+
celerate appreciably the methanolysis of all the substrates
–
compared with the background OCH -promoted reaction at
3
s
the pH where the catalyzed reactions are conducted. For ex-
s
ample, the acceleration of the methanolysis of fenitrothion
Reuse of polymer catalysts
(
11), mediated by the catalyst at an apparent concentration
2
+
Except in the case of the methanolysis of substrate 10, the
activity of most of the polymeric catalysts showed good sta-
bility over several catalytic cycles. With substrate 9, the sec-
of 1 mmol/L (0.028 g of DVB50-(II) 7a/Cu suspended
6
in 2.5 mL of solution) is a factor of 2.9 × 10 greater at
s
s
pH = 9.
2+
ond-order rate constant of 0.1 g of Macro-PL-(II) 7a-Cu
2
+
In the case of the polymers containing 8/Zn , the k val-
2+
–1 –1
2
(
[Cu ] = 9.20 mmol/L) is stable 0.14 ± 0.02 (mol/L) s
ues are higher than those obtained with 7a/M2 (see Tables 2
+
over 10 consecutive experiments. Similar experiments con-
ducted with Macro-PL(II) Zn /7a polymers showed a large
and 3). Previously we have found that the solution reactions
2+
2
+
of phenanthroline/M complexes are slower than with the
triazamacrocycle/M2 complexes because of the fact that the
former are inactivated by dimerization and must dissociate
to the active monomeric forms (7, 25). However, the
dimerization is minimized or precluded on the polymers so
the phenanthroline grafted resins now become more active
than their triazamacrocyle grafted comparisons (see Macro-
inconsistency in reactivity between cycles (a complete cycle
comprises the reaction to completion, followed by filtration,
washing of the recovered polymer with 50 mL of methanol,
and drying in air overnight). However, it was observed that
+
2+
the Macro-PL(II) Zn -loaded polymers do recover complete
reactivity when they are allowed to stand in the N-iso-
propylmorpholine buffer solution for more than 12 h after a
2
+
2+
PL-(II) 8/Zn and Macro-PL-(II) 7a/Zn entries in Tables 2
cycle. This phenomenon is tentatively attributed to an inter-
and 3).
2+
action between CO and Zn /7a complex in the air, which
2
As shown in Fig. 2, a plot of the pseudo first-order rate
reversibly inhibits the catalyst. This decrease of reactivity is
s
2
+
constant for the methanolysis of 9 at pH = 8.7 as a function
s
not observed with material functionalized with 8/Zn .
As a further check to see that any loss in acitivty was not
due to the loss of metal ion through subsequent reactions,
we have reanalyzed the polymers for metal ion content fol-
lowing at least three cycles. For example, Macro-Ald
2
+
2+
of weight of added Macro-PL-(II)7a/Cu or 7a/Zn poly-
mer is linear, indicating there is no saturation phenomenon
such as was observed with a previously reported (9) catalyst
and the substrate diphenyl p-nitrophenyl phosphate in aque-
ous solution. The same linear dependence was observed with
2
+
2+
7
a/Cu and Macro-Ald 7a/Zn , after at least three cycles
2
+
2
+
the 8/Zn -functionalized polymer except at high weight,
reacting with 9, showed an analytical Cu loading of 0.17
and 0.15 mmol/g before and after use, while the Zn2+ load-
ing was 0.023 and 0.020 mmol/g before and after use. While
the absolute numbers seem to show some decrease after use,
the fact that the catalytic activity is unchanged with 9 over
prolonged reuse suggests that the analytical numbers are the
same within experimental uncertainty.
where the reaction rate depends on the frequency of shaking.
There are other subtle differences observed between the
phenanthroline and triazamacrocyle grafted complexes. In
2
+
the case of 8/Zn grafts on the Macro-PL polymer, stronger
absorption of the phenol products is initially observed rela-
2
+
tive to the 7a/M material. However, after several reactions
©
2007 NRC Canada

9
8
Can. J. Chem. Vol. 86, 2008
Table 5. Apparent second-order rate constants for different poly-
Fig. 3. UV spectra for the disappearance of 10 (at 0.3 mmol/L)
catalyzed by DVB50-(II) 7a/Cu ([Cu ] = 6.8 mmol/L) at s pH =
9.1.
2
+
2+
2+
2+
s
mer resins functionalized with 7a/M or 8/Zn , determined at
s
pH = 8.9 in methanol buffered with N-iso-propylmorpholine,
s
–
4
T = 25 °C, [10] = 3 × 10 mol/L.
1
.8
k (10), 1st exp.
((mol/L) s )
k (10), 2nd exp.
((mol/L) s )
2
2
1.6
1.4
–
1 –1
–1 –1
Polymer
DVB50 7a/Cu2+
3.1
0.36
2
+
Macro-Ald 7a/Cu
0.22
0.17
0.20
0.49
No reaction
0.011
0.18
1
.2
Meso-Ald 7a/Cu2
Macro-Ald 7a/Zn
DVB50-hl 8/Zn2
+
2
+
1.0
+
0.49
0
0
0
.8
.6
.4
However, in the case of O-ethyl-S-3,5-dichlorophenyl
methylphosphonothioate (10) the results given in Table 5
with DVB20 and DVB50 show that the reactivity of the sup-
ported Cu((II) catalysts decreases with each cycle. For ex-
ample, with [10] = 0.3 mmol/L, DVB50 7a/Cu exhibits a
k = 3.1 (mol/L) s for its first cycle and 0.36 (mol/L) s
0.2
250
2
+
260
270
280
290
300
–
1 –1
–1 –1
Wavelength (nm)
2
for the second cycle. This drop of reactivity is also accompa-
nied by a change of the blue-green color of the solid to yel-
low, suggesting that the active Cu(II) form of the metal ion
was reduced to Cu(I). Monitoring the reaction of
Fig. 4. Pseudo first-order rate constant, kobs, for the methanolysis
of 9 (10 cycles each with 0.03 mmol/L) with functionalized
2
+
s
Macro-PL-(II) 8/Zn (50 mg) at pH = 8.9 in presence of 2%
s
0
.3 mmol/L 10 at 253 nm shows that the starting material
v:v of water.
disappears, but none of the thiolate product, which should
absorb strongly at 270 nm, is observed to appear, Fig. 3).
This observation, coupled with the loss of activity of the cat-
alyst suggests that the thiolate product is absorbed by the
catalyst and oxidized to the disulfide with concomitant re-
duction of the Cu(II) to Cu(I) and loss of activity. Although
it seems counterintuitive that the small amount of S-
containing substrate could inactivate all the Cu(II) through
reduction, it is possible that there exists a variety of Cu-
containing sites that have variable accessibility, with the
most available and reactive ones being inactivated first.
0
.16
.14
0
0.12
0
0
.10
.08
0.06
0.04
2
+
For the Zn catalysts, a redox reaction between metal and
thiolate cannot happen, and as shown in Table 5 there is no
loss of reactivity observed for complex with 7a and 8.
0
0
.02
.00
1
2
3
4
5
6
7
8
9 10
Influence of water
Experiments to determine the effect of 2% of added water
on the reactivity of the polymers in methanol were con-
Run
ducted in the presence of N-iso-propylmorpholine buffer
porosity in the activity of these supported catalysts. Since
the polystyrene matrices used here as support materials do
s
(
6.8 mmol/L) at pH = 8.9. The results over 10 cycles (de-
s
2
+
fined earlier) for the reaction of 9 mediated by 50 mg of
not swell in methanol solvent during the M -complexation
steps, the mesoporous polymers have the accessible catalytic
sites present only on the surface of beads. It is known (21)
that catalytically active polymers having an increased pore
size allow an increased permeation of reagent and substrate
into the beads, effectively increasing the local concentration
of accessible catalyst. The activities of the synthetic resins
made here are around 10 times better than the commercial
polystyrenes, which is probably due, at least in part, to an
increase in their pore size relative to the commercial
macroporous polymers. However, the accessibility is not the
only parameter that explains the difference of reactivity. The
concentration of catalytic sites relative to the surface area is
also important. The rather small bead size of the synthesized
polymers and their higher loading gives a higher concentra-
tion of catalytic species on the surface. This is demonstrated
by the difference in reactivity observed between Macro-PL
Macro-PL-(II) 8/Zn2 ([Zn ] = 1.96 mmol/L) are reported
+
2+
graphically in Fig. 4.
The first reaction is a reference one for the reaction using
substrate 9 without water, after which the 2% water was
added to the UV cell for all the subsequent reactions. As can
be judged from the appearance of Fig. 4, water continually
degrades the activity until it reaches a stable value of
–
1
0
.03 min after the 9 runs, corresponding to a loss of 85%
of the initial reactivity.
General comments on activities
Comparison of the kinetic reactivities given in Table 3
suggests a general order of reactivity of Meso-Ald < Macro-
Ald < Macro-PL < Macr-PL-hl ≈ synthesized polymers. The
difference in reactivity between mesoporous and
macroporous commercial polymers shows the importance of
©
2007 NRC Canada

Didier et al.
99
Fig. 5. Continuous flow system of total volume 1.5 mL, with
polymer in the column represented as the shaded rectangle, a
flow through UV cell, and a peristaltic pump to drive the solu-
tion at a flow rate of 1.17 mL/min.
Fig. 6. Absorbance vs. time curves for the disappearance of 9
(0.03 mmol/L) (ꢀ, absorbance at 275 nm) catalyzed by 0.113 g
2
+
of functionalized Macro-PL 7a/Cu and for the appearance of
s
s
p-nitrophenol (᭿, absorbance at 310 nm) at pH = 8.8.
0
0
0
0
.8
.7
.6
.5
0.0
2.5
5.0
7.5
10.0
12.5
Time (min)
7
/Cu2+ and Macro-PL-(II) 7/Cu2+ for which the matrices are
Fig. 7. Pseudo first-order rate constant, kobs, for the methanolysis
2
+
the same, but the loading of Macro-PL-(II) is higher by a
factor 2 (see Table 1). The main difference between those
materials is the surface concentration of Cu , but the rate
constant for the reaction with 9 and 11 vary by factors of 7
and 10 respectively. The increase of reactivity in the case of
higher Cu concentration on the surface is consistent with a
cooperative effect between two neighboring metal ions.
of 9 (at 0.03 mmol/L) with Macro-PL-(II) Cu /7a (0.1130g) in
s
s
a column at a flow rate of 1.17 mL/min at pH = 8.8.
2
+
0.8
2
+
0
.6
Column system
The most efficient materials made with polystyrene resin
purchased from Polymer Laboratories (PL-CMS MP resin)
were used in an improvised column system. This system, as
illustrated in Fig. 5, consists of a variable-flow low-flow
peristaltic pump connected to a column (i.d. 3.0 mm, length
0.4
0
0
.2
.0
5
~
(
0 mm, from Chrom Tech), which was filled with about
0.1 g of the polymer support, and an injection valve
Chrom Tech, OM-1114) permitting the injection of a known
1
2
3
4
5
6
7
8
9 10
volume of methanol containing the OP substrate.
Run
Also included in the system is a UV–vis flow cell that al-
lows monitoring of the absorbance vs. time profile of the cir-
culating solution. The total volume of the circulating system
is around 1.5 mL. A solution containing the OP substrate
was introduced through the system and the valve was closed
to permit continuous circulation. Shown in Fig. 6 is the
2
+
stability was observed for 11 with Macro-PL-(II) 7a/Cu ,
and 9 and 10 with Macro-PL-(II) 7a/Zn .
2
+
To demonstrate turnover of the catalyst on the polymer, an
experiment monitoring the decomposition of an excess of
substrate was conducted wherein 25 mL of methanol solu-
tion containing 1.2 × 10 mmol of 9 was circulated through
a column (i.d. 3.0 mm, length 25 mm) containing 46.6 mg of
Macro-PL-(II) 8-Zn (total amount of Zn was 4.6 ×
10 mmol). The observed rate constant for the disappear-
ance of the substrate was 0.002 ± 0.0007 min , correspond-
ing to a rather large half-time of 5.75 h. However, under
these conditions the volume of the column containing the ac-
tive polymer was only 0.175 mL, and since the flow rate was
0.29 mL/min, the great bulk of the substrate was not in con-
tact with the polymer. These data indicate that the polymer
is capable of destroying an excess of substrate, surviving
prolonged contact with the reacting system and suggest that
far greater efficacy would be possible with large columns in
kinetic curve of disappearance of
9
catalyzed by
2
+
–2
functionalized Macro-PL 7/Cu (0.1130 g) with a rate flow
–
1
of 1.17 mL min .
2
+
2+
Both absorbance vs. time curves can be fitted by NLLSQ
fitting to a first-order kinetics model giving a pseudo first-
–
3
–
1
–1
order rate constant of 0.72 ± 0.05 min . In general for this
circulating system, the data do not exactly follow a first-
order profile because of the fact that they have stairlike pro-
file, where each step corresponds to one cycle of the system.
In the case of the data in Fig. 6, the reaction appears to be
done after three cycles through the polymeric support.
As shown in Fig. 7, the reaction of phosphonate 9 with
Macro-PL-(II) 7a/Cu2 has the same rate constant over 10
different injections of 0.03 mmol/L OP solution. The same
+
©
2007 NRC Canada

1
00
Can. J. Chem. Vol. 86, 2008
circulating systems, where the ratio of the column volume to
total circulating volume is maximized.
5. (a) J.S. Tsang, A.A. Neverov, and R.S. Brown. J. Am. Chem.
Soc. 125, 7602 (2003); (b) T. Liu, A.A. Neverov, J.S.W.
Tsang, and R.S. Brown. Org. Biomol. Chem. 3, 1525 (2005);
(
c) R.E. Lewis, A.A. Neverov, and R.S. Brown. Org. Biomol.
Conclusion
Chem. 3, 4082 (2005); (d) S.A. Melnychuk, A.A. Neverov,
and R.S. Brown. Angew. Chem. Int. Edit. 45, 1767 (2006).
. J.A.W. Tsang, A.A. Neverov, and R.S. Brown. Org. Biomol.
Chem. 2, 3457 (2004).
. A.A. Neverov and R.S. Brown. Org. Biomol. Chem. 2, 2245
(
. These comparisons are made under the reasonable assumption
that the background reaction is attributable to OCH at near
neutral pH values, and that the autoprotolysis constant of
methanol is 10
Sales. J. Chem. Soc., Perkin Trans. 1, 2, 1953 (1999).
. F.M. Menger and T. Tsuno. J. Am. Chem. Soc. 111, 4903
(
10. (a) Q. Lu, A. Singh, J.R. Deschamps, and E.L. Chang. Inorg.
Chim. Acta, 309, 82 (2000); (b) C.M. Hartshorn, A. Singh,
and E.L. Chang. J. Mater. Chem. 12, 602 (2002); (c) C.M.
Hartshorn, J.R. Deschamps, A. Singh, and E.L. Chang. React.
Funct. Polym. 55, 219 (2003).
In this work we have shown that polymer-supported metal
and (or) complex catalysts can be prepared by grafting a
ligand (7a or 8) onto a suitable chloromethylated polysty-
6
7
8
2
+
2+
rene resin, which can then be loaded with M (Cu or
2004).
2
+
Zn ). This catalytic matrix shows good activity for mediat-
ing the methanolysis of different kinds of OP esters
like O-ethyl-S-3,5-dichlorophenyl methylphosphonothioate
–
3
s
s
(
10), O-ethyl-O-4-nitrophenyl methylphosphonate (9), and
–16.77
. E. Bosch, F. Rived, M. Rosés, and J.
fenitrothion (11), which are simulants for V-agents, G-
agents, and P=S pesticides. In the most favourable case,
9
8 mg of DVB50-(II) 7a/Cu2 suspended in 2.5 mL of solu-
+
2
1989).
6
tion provides a factor of 2.9 × 10 in acceleration of the
methanolysis of fenitrothion over the background reaction at
s
s
pH = 9. The methanolysis reactivity is shown to be en-
hanced by a large porosity of the solids, which allows access
of the OP ester substrates to the catalytic centers. This mate-
rial can be used in column systems with a continuous flow
and may show some promise for larger scale applications to
cleanups of OP esters, where the contaminants can be dis-
solved in methanol that is passed through a column for de-
contamination.
11. (a) S.G. Srivatsan and S. Verma. Chem. Eur. J. 7, 828 (2001);
(
5
b) S.G. Srivatsan, M. Parvez, and S. Verma. Chem. Eur. J. 8,
184 (2002); (c) V. Chandraskhar, A. Athmoolan, S.G.
Srivatsan, P. Shanmuga Sundaram, S. Verma, A. Steiner, S.
Zacchini, and R. Butcher. Inorg. Chem. 41, 5162 (2002);
(
d) S.G. Srivatsan and S. Verma. Chem. Commun. (Cam-
bridge), 515 (2000).
2. A.I. Hanafy, V. Lykourinou-Tibbs, K.S. Bisht, and L.-J. Ming.
Inorg. Chim. Acta, 358, 1247 (2005).
3. S. Durie, K. Jerabek, C. Mason, and D.C. Sherrington.
Macromolecules, 35, 9665 (2002).
4. A. Chemin, H. Deleuze, and B. Maillard. Eur. Polym. J. 34,
Acknowledgements
1
1
1
1
The authors gratefully acknowledge the financial assis-
tance of the Natural Science and Engineering Research
Council of Canada (NSERC), Queen’s University, the Can-
ada Foundation for Innovation, and the Canada Council for
the Arts. MFM thanks NSERC for the award of a CGS-M
postgraduate scholarship EC thanks NSERC for the award of
a Summer Undergraduate Research Award, and KGC thanks
Queen’s University for a Summer Work Experience Award.
1
395 (1998).
5. (a) K. Binnemans, P. Lenaerts, K. Driesen, and C. Görller-
Warland. J. Mater. Chem. 14, 191 (2004); (b) P. Lenaerts, K.
Driesen, R. Van Deun, and K. Binnemans. Chem. Mater. 17,
2148 (2004).
1
1
6. P. Brunet and J.D. Wuest. J. Org. Chem. 61, 1847 (1996).
7. Y. Chauvin, D. Commereuc, and F. Dawans. Prog. Polym. Sci.
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©
2007 NRC Canada