Mn-tetraarylporphyrins bearing N-alkyl sulphonamido tails: Effect of the length and polarity of the chains on physical properties and reactivity

Article abstract of DOI:10.1016/S1381-1169(99)00239-3

Manganese-complexes of a new series of tetraarylporphyrins, featuring both chlorine atoms in ortho, ortho' positions and N-mono- or N,N- disubstituted sulphonamido groups in meta on the meso-phenyls, were used as catalysts in the epoxidation of α-olefines in the presence of diluted (17.5%) H₂O₂ as primary oxidant. The catalytic efficiency of these catalysts is related to the polarity of the chains and the N,N- dialkylsulphonamido porphyrins turned out to be more reactive than the robust Mn-TDCIPP in the epoxidations of styrenes. (C) 2000 Elsevier Science B.V.

Full text of DOI:10.1016/S1381-1169(99)00239-3

Ž
.
Journal of Molecular Catalysis A: Chemical 151 2000 17–28
www.elsevier.comrlocatermolcata
Mn-tetraarylporphyrins bearing N-alkyl sulphonamido tails:
effect of the length and polarity of the chains on physical
properties and reactivity
a
a
b
Stefano Banfi a,), Claudio Cavalieri , Marco Cavazzini , Artan Trebicka
a
CNR Center and Department of Organic and Industrial Chemistry of the UniÕersity of Milano, Via C. Golgi 19, 20133 Milan, Italy
b
Department of Biology, UniÕersity of Tirana, Tirana, Albania
Received 22 January 1999; received in revised form 16 April 1999; accepted 19 May 1999
Abstract
Manganese-complexes of a new series of tetraarylporphyrins, featuring both chlorine atoms in ortho, orthoX positions
and N-mono- or N,N-disubstituted sulphonamido groups in meta on the meso-phenyls, were used as catalysts in the
Ž
.
epoxidation of a-olefines in the presence of diluted 17.5% H2O2 as primary oxidant. The catalytic efficiency of these
catalysts is related to the polarity of the chains and the N,N-dialkylsulphonamido porphyrins turned out to be more reactive
than the robust Mn-TDClPP in the epoxidations of styrenes. q 2000 Elsevier Science B.V. All rights reserved.
Keywords: Hydrogen-peroxide; Mn-tetraarylporphyrins; a-Olefines; Epoxidation
Ž
.
1. Introduction
alkenes i.e., Cyclooctene, Styrenes ; often these
reactions are over in less than 1 h at room
w
x
Since the middle of the eighties, metallo-te-
traarylporphyrins have been widely used as cat-
alysts in oxidation reactions in the presence of a
temperature or below 5–7 .
By using an excess of oxidant with respect to
the substrate, the efficiency of the catalytic sys-
tem, meant as maximum turnover numbers
Ž
.
primary oxidant oxygen donor, OD , with the
purpose of obtaining a synthetic model of the
Ž
.
TNmax , depends on several factors such as the
w
x
enzymes of the cytochrome P-450 family 1–4 .
Under well defined reaction conditions man-
ganese- or iron-porphyrins can perform several
hundred turnovers in a-olefin epoxidations or in
alkane mono oxygenations and also reach thou-
sand turnovers in the epoxidation of reactive
nature of the oxygen donor, the presence of
cocatalysts, the structure of both substrate and
of the catalyst itself; among these factors the
last topic was the most widely studied through-
out the last decade. Indeed, the inactivation of
the catalyst, ascribed to the demolition of the
tetrapyrrole macroring under drastic oxidation
conditions, is the side of this catalytic system.
In the attempt to minimize this problem, the
electronic and steric characteristics of tetraphen-
)
Corresponding author. Department of Structural and Func-
tional Biology, University of Insubria, Via H.J. Dunant, 3, 21100
Varese, Italy
1381-1169r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved.
Ž
.
PII: S1381-1169 99 00239-3

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18
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
ylporphyrin were largely modified by the
introduction of substituents on the catalyst peri-
to be reduced to the corresponding amino groups
which, in turn, are suitable for linkage of lateral
chains through amido bond.
w
x
phery 8–11 . Thus, bulky andror electronwith-
drawing atoms or groups were introduced on the
meso-phenyl rings and it was found that those
placed in the ortho positions exerted a benefi-
cial effect on porphyrin stabilities. As a conse-
quence of these studies, in catalytic oxidations,
the metallo complexes of the commonly used
‘‘naked’’ tetraphenylporphyrin have been re-
More appealing is the introduction of sulphon-
yl groups which show electronic effect compa-
rable with that one of the NO2 group and
besides allow the linkage of tails without loss of
the electronic effect. Furthermore, sulphon-
amides are fairly more stable than carboxy-
amides. The major drawbacks in the synthesis
of sulphonated porphyrins is given either by the
harsh reaction conditions employed for the
Ž
.
placed with the tetrakis 2,6-dichlorophenyl
Ž .
porphyrin 1 . The latter is a catalyst known as
particularly robust and easily available, then
metallo-complexes of 1 must be considered as
reference model. All the newly synthetized por-
phyrins featuring different structure should be
compared with it in order to unambiguously
define their efficiency as oxidation catalysts.
More recently, halogens were placed on the
b-pyrrole positions, thus producing a new class
of porphyrins which was called ‘‘third genera-
tion porphyrins’’ to differentiate them from
those bearing substituents only on the meso
phenyls; the efficiency of such catalysts is cur-
rently under debate because the presence of
sterically demanding atoms on the b-positions
causes ruffling of the porphyrin plane, hence,
both the reactivity and the stability are strongly
Ž
.
sulphonation fuming H2SO4 and by the work-
up which give sulphonic acid or sulphonate
derivatives, both insoluble in organic solvents.
Actually sulphonyl substituents have been
widely used to allow the solubility of both
porphyrins and of phthalocyanines in water
w
x
21,22 . The sulphonic acid derivatives can be
converted into the corresponding sulphonyl-
chloride by the reaction with PCl5 at 1508C
w
x
23 . Recently, a more convenient synthesis of
sulphonylchloride functionalized porphyrins has
been reported by Rocha Gonsalves et al.; in this
case, the reaction is carried out on tetraarylpor-
phyrins with neat chlorosulphonic acid, the work
up directly producing the desired compound
w
x
24 .
In this work, we report the synthesis of man-
w
x
affected 12–14 . Only in the case of metallo-te-
w
Ž
tramesitylporphyrin M-tetrakis 2,4,6-trimethyl-
ganese-tetraarylporphyrins featuring one or two
side chains linked through one sulphonamido
group on each 2,6-dichlorophenyl rings. The
catalytic efficiency of these catalysts in alkene
epoxidations, with H2O2 as oxygen donor, will
be discussed in relation to the number, polarity
and length of the lateral chains.
.
x
phenyl-porphyrin the b-perchlorinated deriva-
tive was found more robust with respect of the
not halogenated parent porphyrin, while it was
experimentally and theoretically demonstrated
that the same effect does not occur when eight
chlorine atoms are introduced on b-pyrrole po-
w
x
sitions of 1 15–17 .
On the other hand, the presence of electron-
withdrawing substituents placed in the meta or
para positions of the phenyl rings of catalyst 1
further increases the stability of the macroring
as it was found by us in the case of nitro groups
2. Results and discussion
Ž
The free base 5,10,15,20-tetrakis 2,6-dichlo-
ro-3-chlorosulphonyl-phenyl porphyrin 2 was
obtained in 90% yield from H2-TDClPP 1 with
chlorosulphonic acid as reported in literature
w
x
.
18–20 . Indeed, a few examples concern with
the use of nitro substituted tetraarylporphyrins
as catalysts; as a matter of fact, NO2 groups are
often introduced on the porphyrin frame mostly
w
x
24 and recovered as pure brown solid by re-

(
)
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
19
Ž .
precipitation from CHCl3rn-hexanes1r5. The
sulphonamido porphyrins 3–9 were synthetized
in a 50–70% yield by heating under reflux 2
with an excess of the desired primary or sec-
ondary amine. Porphyrins 3–6 and 9 were ob-
tained from 2 using commercially available
amines, while the synthesis of compounds 7 and
8 required the preparation of the unprecedented
amines 10 and 11. The synthesis of 10 is re-
ported in Scheme 1.
ate A were also added as cocatalysts in few
molarequivalent with respect to the catalyst
Ž
.
LrMn-porph s 5; ArMn-porph s 10 . a-
Olefins were chosen to emphasize the efficiency
of the catalysts being the epoxidation of such
substrates more difficult compared with that of
di- or tri-substituted alkenes; furthermore, the
epoxidations were carried out also in the pres-
ence of the known robust catalyst Mn-TDClPP
Ž
.
Mn-1 and its turnover numbers were consid-
Amine 11 was obtained starting from te-
ered as reference for the evaluation of the cat-
Ž
.
traethylenglycol TEG , firstly treated with one
equivalent of sodium in dioxane and then re-
acted with an excess of 1-bromododecane; the
alytic activities.
The results are reported in Tables 1 and 2.
The most efficient among the new catalysts was
then used in the epoxidation of some alkenes,
once more comparing its activity with Mn-1
Ž
.
tetraethylenglycol-monoether TEG-OC12 was
then subjected to the same reaction sequences
reported for 10.
Ž
.
Table 3 .
Ž
.
The corresponding manganese III -com-
The epoxidations of both 1-octene and 1-
Ž
.
plexes Mn-3–Mn-9 were prepared by stan-
dard methods refluxing free base porphyrins
3–9 in anhydrous DMF in the presence of
Mn OAc Fig. 1 25 .
These metallo-complexes were tested in the
epoxidations of 1-dodecene and 1-octene alk-
dodecene indicate the reactivity of catalysts
Mn-3–Mn-9 strongly dependent on the nature
of the sulphonylamino group; the N-monoalkyl
substituted sulphonamido porphyrins are always
less reactive than the N,N-dialkyl tailed ones
featuring the same number of carbon atoms
Ž
. Ž
. w x
2
Ž
.
Ž
enerMn-porphs500 carried out under two
compare Mn-3 with Mn-4 and Mn-5 with
Ž
.
.
phase conditions CH2Cl2rH2O , following the
Mn-6 ; among the dialkyl-sulphonamido por-
phyrins the length of the hydrocarbon chains
does not particularly influence the reactivity as
evidenced by the comparison between the N-di-
butyl Mn-4 and the N-dioctyl Mn-6, the former
w
x
procedure previously reported by us 18,26 at
08C, in the presence of an excess of 17.5%
H2O2 with respect to the substrate. N-hexyl-
Ž .
imidazole as axial ligand L and sodium benzo-
Scheme 1.

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)
20
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
Fig. 1.
being only slightly more reactive than the latter.
For the sake of knowledge, we have also syn-
thetized the corresponding N-diethyl derivative
The reactivity of new catalysts dramatically
decreases when hydrophilic chains are present
on the periphery of the macroring. Conversions
are nil in the case of catalyst Mn-7 which
shows highly hydrophilic polyethylenglycol tails
and are still very low with catalyst Mn-8, which
features chains with hydrophilic section in the
Ž
.
Mn-9 which, however, showed the same reac-
tivity of Mn-4 in the epoxidation of 1-dode-
cene, thus confirming the absence of effects that
can be ascribed to the length of the chains.
These results are partially in agreement with
those reported in 1996 by Rocha Gonsalves et
al., which, in the epoxidation of cyclooctene,
found a lower reactivity of both mono N-alkyl
substituted and N, N-diethylsulphonamido-
Ž
.
inner part tetraethylenglycol moiety and a
lipophilic section due to the linear C12 hydro-
carbon unit in the outer part.
These results can be explained considering
two factors related to the presence of chains on
w
x
Ž .
porphyrins with respect to Mn-1 27 .
the periphery of the tetraarylporphyrins: i steric

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S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
21
Table 1
Epoxidation of 1-dodecene catalyzed by Mn-1, Mn-3–Mn-9a
Catalyst
Time
Conv.%b
Turnover
numbersc
Time
Conv.%b
Turnover
numbersc
Ž
.
Ž
.
min
min
Mn-1
Mn-3
Mn-4
Mn-5
Mn-6
Mn-7
Mn-8
Mn-9
30
30
30
30
30
30
30
30
64
56
66
46
65
–
320
280
330
230
325
–
60
60
60
60
60
60
60
60
73
60
74
54
73
–
365
300
370
270
365
–
15
66
75
330
16
72
80
360
a In CH2Cl2 , Ts08C, in the presence of sodium benzoate
A
Ž
.
Ž .
and N-hexylimidazole, as axial ligand L . Molar ratios: Mn–P:alkene:
A:Ls1:500:5:10. Aqueous phase at pH 4.5.
b
Ž
.
Values obtained by GC analysis with internal standard; selectivity epoxideralkene reacted G95%.
c mmol reacted alkenermmol Mn–P.
Ž .
.
hindrance and ii polarity of the reaction
N-C16 but with higher polarity, and as said
medium in the surroundings of the metal centre.
As far as it concerns the first point, from the
results obtained with catalysts Mn-4, Mn-6 and
before, they show a limited or nil catalytic
activity. These catalysts were synthetized with
the aim to facilitate interaction between the
oxidant aqueous phase and catalyst active centre
through a pseudo reverse micellar system com-
posed by the amphiphilic catalyst, H2O2rH2O
and organic layer. The absence of reactivity
could be imputed to the excess of hydrophilic
moieties of the porphyrins which does not allow
the approach of the substrate to the metal cen-
tre, probably shielded by the presence of water
molecules. Mn-7 and Mn-8 are not soluble in
water, however it has been reported that free
base porphyrins bearing only one polyeth-
yleneglycol tail, although longer than those po-
sitioned on catalyst 7, spontaneously distribute
Ž
Mn-9 in the epoxidation of 1-dodecene Table
.
1 , it is easily inferred that the steric hinderance
is negligible; indeed not only these catalysts
give a comparable TNmax but their catalytic
activities are very close to that one of the
unsubstituted Mn-1 too. However, the alkyl tails
grant to porphyrins Mn-4 and Mn-6 an extreme
solubility in low polar solvent. Particularly the
latter is even soluble in pure hydrocarbons while,
generally, metallo-tetraarylporphyrins are par-
tially soluble in chlorinated solvents only.
Catalysts Mn-7 and Mn-8 feature chains of
Ž
comparable length with respect to Mn-5 mono
Table 2
Epoxidation of 1-octene catalyzed by Mn-1, Mn-3–Mn-8a
Catalyst
Time
Conv.%b
Turnover
numbersc
Time
Conv.%b
Turnover
numbersc
Ž
.
Ž
.
min
min
Mn-1
Mn-3
Mn-4
Mn-5
Mn-6
Mn-7
Mn-8
30
30
30
30
30
30
30
70
59
70
42
66
–
350
295
350
210
330
–
60
60
60
60
60
60
60
80
63
78
45
78
–
400
315
390
225
390
–
18
90
21
105
a In CH2Cl2 , Ts08C, in the presence of sodium benzoate
A
Ž
.
Ž .
and N-hexylimidazole, as axial ligand L . Molar ratios: Mn–P:alkene:
A:Ls1:500:5:10. Aqueous phase at pH 4.5.
b
Ž
.
Values obtained by GC analysis with internal standard; selectivity epoxideralkene reacted G95%.
c mmol reacted alkenermmol Mn–P.

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22
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
Table 3
Epoxidation of styrenes catalyzed by Mn-1 and Mn-6a
Catalyst
Time
Styrene conv.%b
3-Nitrostyrene conv.%b
4-Methystyrene conv.%b
c
c
c
Ž
.
Ž
.
Ž
.
Ž
.
min
turnovers
turnovers
turnovers
Ž
.
.
.
.
.
Ž
.
.
.
.
.
.
Ž .
13 65
Mn-1
Mn-6
Mn-1
Mn-6
Mn-1
Mn-6
5
5
10
10
20
20
28 140
25 125
Ž
Ž
Ž
.
.
.
.
.
70 350
70 350
50 250
Ž
Ž
Ž
30 150
61 305
46 230
Ž
Ž
Ž
100 500
75 375
82 410
Ž
Ž
Ž
54 270
100 500
71 355
Ž
Ž
–
78 390
88 440
a In CH2Cl2 , Ts08C, in the presence of sodium benzoate
A
Ž
.
Ž .
and N-hexylimidazole as axial ligand L . Molar ratios: Mn–P:alkene:
A:Ls1:500:5:10. Aqueous phase at pH 4.5.
b
Ž
.
Values obtained by GC analysis with internal standard; selectivity epoxideralkene reacted G95%.
c mmol reacted alkenermmol Mn–P.
between benzenerwater phases after some hours
under stirring and the rate depends on the con-
formation of the PEG chain; it is known that
PEG can exhibit two different conformations,
one trans with non polar character and another
gauche which is polar, the latter conformer
no conversion was observed even after long
reaction time. We believe the absence of reac-
tivity have to be ascribed to the missed forma-
tion of the high valent metallo-oxo species
Ž
.
MsO , which is actually the active species.
There are two possible explanations why the
w
x
being favoured by low temperature 28 . As
confirmation of the low catalytic efficiency of
PEG tethered metallotetraarylporphyrins, Monti
metallo-oxo species is not generated in apolar
Ž .
medium: a the aqueous oxidant hardly dis-
solve in the organic phase, then its concentra-
w
x
Ž
et al. 29 recently reported few turnovers up to
tion is too low to give MsO with reasonable
.
Ž .
10 in the epoxidations of cyclooctene and 1-
rate; b the formation of MsO is hampered by
dodecene carried out in micellar system.
the undissociation of the metallo counterion in
Catalysts Mn-6 and Mn-1 were also used in
the epoxidations of styrenes; with these alkenes
the reactivity of the former porphyrin is by far
higher than that one showed by the reference
the low polar medium.
Ž .
Point a was confuted by the addition of a
Ž
highly lipophilic phase-transfer catalyst di-
cyclohexane-18-crown-6, 10 molarequiv. with
respect to the porphyrin , thus ensuring the in-
teraction between the aqueous oxidant and the
Ž
.
.
catalyst Table 3 . With Mn-6 the conversion of
styrene, 3-nitro-styrene and 4-methyl-styrene are
100, 75 and 82%, respectively after 10 min,
while the epoxidations catalyzed by Mn-1 reach
comparable conversion only at higher reaction
catalyst; nevertheless, no conversion was ob-
Ž
served. Under the standard conditions set up by
our group, the polarity of CH2Cl2 is adequate
Ž
.
times about 20 min later .
to dissolve a sufficient amount of H2O2 or
w
x .
Probably, the eight lipophilic chains provide
a microenviromental effect which favours the
approach of the double bond to the catalytic
centre, similarly to what reported by Groves and
HOCl in the organic phase 31,32 . The second
important factor which can bias the reaction
outcome is the effect of the low polar alkene
solution on the porphyrin itself. In the case of
w
x
Ž
.
Neumann 30 in the case of membrane span-
ning steroidal metalloporphyrin.
manganese III -tetraarylporphyrins, the mecha-
nism of the metallo-oxo species formation is
Ž
.
The peculiar solubility of Mn-4 and Mn-6
prompted us to carry out the oxidations in the
absence of toxic chlorinated solvent, just stir-
ring the catalyst and the alkene with H2O2, in
the presence of usual cocatalysts. Unfortunately,
known in its fundamental aspects Scheme 2 .
The key step is the coordination of a molecule
Ž .
of heterocyclic nitrogen ligand L on the metal
atom at the free side of the planar macroring,
followed by the dissociation KD of the counter
Ž
.

(
)
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
23
Scheme 2.
Ž
anion, which leaves the metal free to react with
calculated in CH2Cl2 log b2 s6.8 and 4.6,
Ž
.
.
the primary oxygen donor OD . In this last
step, the molecule of catalyst changes from
uncharged to a zwitterionic form, the positive
charge being placed on the metal with the anion
free in solution. The zwitterionic form is
favoured by solvents with high dielectric con-
stants but is inhibited in apolar solutions.
respectively , thus strongly indicating that, in
apolar solvent, Mn-porphyrins exist as stable,
neutral hexacoordinate complexes in which both
axial positions are occupied, one by the counter-
ion and the other by the nitrogen base. In
confirmation of the importance of the polarity
of reaction medium, we run a set of reactions
increasing the alkenerCH2Cl2 VrV ratio from
9r1 up to 1r9; the results indicate a constant
increase of reaction rates, the maximum being
obtained with the 1r9 ratio. This ratio corre-
In order to get experimental evidences on this
aspect of the reaction mechanism, we have mea-
sured, by means of spectrophotometric titrations
in the visible region, the binding constants be-
tween Mn-6 and N-hexylimidazole both in
w
x
sponds to an alkene s0.6 M, which is very
close to the standard conditions employed by us
in the kinetic investigations.
w
x
CH2Cl2 and cyclooctane 10,31,32 .
According to the same considerations re-
ported above for the reaction between metallo-
porphyrin and oxidant, the binding constant of
Ž
.
bis-coordination K2 of the axial ligand on the
metal should be largely decreased in apolar
solvent, while the first coordination constant
3. Conclusions
In the epoxidation of a-olefins promoted
by 17.5% H2O2, among the unprecedently
reported manganese-3-sulphonamido-2,6-di-
Ž
.
K1 is unaffected; indeed, we have found that
b2 value b2 sK2 obtained in hydrocarbon is
two orders of magnitude lower than the one
Ž
.
Ž .
chlorophenyl-porphyrins Mn-4–Mn-9 , the

(
)
24
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
Ž
.
N,N-dialkyl tailed Mn-4, Mn-6 and Mn-9
formed on a Lambda 6 Perkin-Elmer spectro-
photometer.
showed a catalytic efficiency comparable or
higher than that one of the robust Mn-TDClPP
Ž
.
Mn-1 . The alkyl chains do not interfere with
the manganese centre, the main feature of cata-
lysts Mn-4 and Mn-6 being an enhanced solu-
bility in pure hydrocarbons; this feature should
allow to lead the reactions in the absence of
chlorinated solvents. Unfortunately, no reactiv-
ity was observed in alkene medium; the expla-
nation of such inertness was found in the ionic
pair, made by Mn III atom and its counterion,
which cannot dissociate in low polar solvent,
thus preventing the coordination of the primary
4.1.1. Synthesis of amines
X
(
)
4.1.1.1. O- 2-Aminoethyl -O -methylpolyethyl-
(
ene glycol 350 aminopolyethylene glycol 350-
)
Ž
monomethyl ether 10. Synthesis of O- 2-
X
.
methanesulphonylethyl -O -methylpolyethylene
Ž
.
glycol 350 Ms-PEG350-OMe 10a. To a solu-
qŽ
.
Ž
.
tion of 10.5 g 0.03 mol of polyethylene glycol
350-monomethyl ether in 40 ml of anhydrous
pyridine, cooled with an ice bath, were slowly
Ž
.
Ž
.
oxidant OD on the metal centre. Catalysts
featuring polyethyleneglycole chains were found
completely unreactive under standard reaction
conditions; nevertheless, these amphiphilic cata-
lyst could find application under reverse micel-
lar or microemulsion conditions. Studies on this
topic are under investigations.
added 3.1 ml 4.57 g, 0.04 mol of freshly
distilled methanesulfonylchloride, keeping the
temperature below 58C. After addition, the solu-
tion was stirred for 1 h at the same temperature,
then the reaction mixture was brought at pH 1.0
carefully adding HCl conc. at a such rate to
keep the temperature below 158C. The acid
Ž
.
layer was extracted with CH2Cl2 3=30 ml
and the organic phase was washed twice with
20 ml of 10% HCl and then with water to
neutral pH, dried with Na2SO4 and evaporated.
The raw material was purified by column chro-
4. Experimental
4.1. General methods and materials
Ž
.
matography silica-gel, CHCl3rEtOH 9r1 to
The alkenes and the other products used in
the synthesis were high purity commercial prod-
ucts and were used as received. The CH2Cl2
used for the epoxidations was a ‘‘Baker ana-
lyzed’’ reagent stabilized with amylene. A
17.5% H2O2 was obtained diluting portions of
give the methanesulphonyl-derivative in 90%
1
20
Ž
.
yield 11.5 g, pale yellow oil; nD s1.459 . H
Ž
.
Ž
.
.
NMR 300 MHz, CDCl3 : ds3.05 3H, s ,
Ž
Ž
.
Ž
Ž
.
Ž
3.30 3H, s , 3.50 2H, m , 3.60 22H, br s ,
.
.
3.70 2H, m , 4.35 2H, m .
X
Ž
.
Synthesis of O- 2-phthalimidoethyl -O -
methylpolyethylene glycol 350 Phth-PEG350-
. Ž .
OMe 10b. Ms-PEG350-OMe 4.1 g was
treated with potassium-phthalimide 5.5 g, 0.03
Ž
.
Ž
2 ml of 35% H2O2 Fluka with an equivalent
1
volume of distilled water just before use. H
Ž
NMR were obtained on either Bruker 80 MHz
or 300 MHz instruments. MS-FAB spectra were
registered on a Finningan MAT90 instrument
with 3-nitrobenzyl alcohol as matrix. Analytical
LC was carried out on a 5890 Hewlett-Packard
instrument, with a flame ionization detector
.
mol. in refluxing DMF for 18 h. The mixture
was cooled, filtered on sintered buchner funnel
and the solvent evaporated in vacuo. The residue
was diluted with CH2Cl2 and again filtered to
eliminate the unreacted potassium-phthalimide.
The organic solvent was then dried over Na2SO4
and evaporated; the residue was purified by
Ž
.
FID-2508C and fitted with a 30 m=0.53 mm
RSL-200 column, using the internal standard
method to determine alkene conversions and
epoxide formations. The injector temperature
was kept at 1508C. UV–Vis analyses were per-
Ž
column chromatography silica-gel, CHCl3r
.
Ž
.
EtOH 9r1 to give 3.0 g 65% yield of the
phthalimido-derivative as yellow oil; n2D0 s

(
)
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
25
1
Ž
.
1.514. H NMR 300 MHz, CDCl3 : ds3.35
EtOH. The characteristics of the intermediates
are reported here.
Ž
Ž
.
Ž
.
Ž
.
3H, s , 3.50–3.60 24H, m , 3.70 2H, t , 3.85
2H, t , 7.65 2H, m , 4.82 2H, m .
Amine 10 was finally obtained refluxing the
phthalimido compound 0.92 g, 2 mmol with
an excess of hydrazine hydrate 4 mmol for 5 h
in ethanol. The solvent was then eliminated in
vacuo and the residue taken up into CH2Cl2
and filtered. The organic solution was washed
with diluted HCl and the acid aqueous layer was
again brought to basic pH with NaOH and
extracted with CH2Cl2. The amine was ob-
.
Ž
.
Ž
.
Ms-TEG-OC12: oil, 65% yield after column
Ž
chromatography silica-gel, CH2Cl2rEtOH
99r1 , nD s 1.456; 1H NMR 300 MHz,
20
Ž
.
.
Ž
Ž
.
.
Ž
.
.
Ž
.
.
CDCl3 : ds0.80 3H, t 1.20–1.30 20H, br s ,
Ž
Ž
.
Ž
Ž
3.05 3H, s , 3.43 2H, t , 3.55–3.80 14H, m ,
.
4.38 2H, dd .
Phth-TEG-OC12: yellow oil, 60% yield after
Ž
column chromatography silica-gel, CHCl3r
1
20
.
Ž
EtOH 9r1 , nD s1.497; H NMR 300 MHz,
.
Ž
.
Ž
.
.
CDCl3 : ds0.85 3H, t 1.20–1.30 18H, br s ,
Ž
Ž
.
.
Ž
Ž
.
.
Ž
tained as pure sticky yellow oil 450 mg, 65%
1.55 2H, m , 3.40 2H, t , 3.50–3.65 14H, m ,
25
.
Ž
Ž
.
yield; nD s1.457 after column chromatogra-
3.70 2H, t , 3.84 2H, t , 7.68 2H, m , 7.82
1
Ž
.
Ž
.
phy silica-gel, acetonerEtOH 7r3 . H NMR
2H, m .
Ž
.
Ž
300 MHz, CDCl3 : ds1.70 2H, br s, D2O
Amine 10: pale orange oil, 65% yield after
.
Ž
.
.
Ž
.
Ž
exchange 2.85 2H, t , 3.35 3H, s , 3.45–3.55
column chromatography silica-gel, acetoner
1
20
Ž
.
Ž
.
Ž
4H, m , 3.62 24H, s .
EtOH 7r3 , nD s1.453; H NMR 300 MHz,
.
Ž
.
Ž
.
.
CDCl3 : ds0.85 3H, t 1.20–1.30 18H, br s ,
X
(
)
Ž
.
Ž
4.1.1.2. O- 2-Aminoethyl -O -dodecyltetraethy-
lene glycol aminotetraethylene glycol-mono-
dodecyl ether 11. Synthesis of tetraethylene
glycol monododecyl ether TEG-OC12 : Na 2.3
1.55 2H, m , 1.70 2H, br s, D2O exchange ,
(
)
Ž
.
Ž
.
Ž
.
2.85 2H, t , 3.40 2H, t , 3.50 2H, t , 3.53–3.65
Ž
.
12H, m .
Ž
.
Ž
.
g, 0.1 mol was added in portion to 70 ml of
4.1.2. Synthesis of free-base porphyrins
Ž
.
Ž
.
tetraethylene glycol TEG kept under vigorous
stirring, at room temperature and under nitro-
gen. When sodium was completely consumed,
1-bromododecane 24 ml, 0.1 mol was added
and the reaction mixture heated at 1008C. Stir-
ring was maintained for 24 h then the reaction
H2-tetrakis- 2,6-dichlorophenyl porphyrin 1
was synthetized following literature procedure
w
x
Ž
33 and H2-tetrakis- 2,6-dichloro-3-chloro-
Ž
.
.
sulphonyl-phenyl porphyrin 2 was obtained ac-
cording to the method described by Rocha Gon-
w
x
salves et al. 24 .
Ž
.
mixture was cooled, diluted with Et2O 200 ml
and filtered to eliminate the salts. The organic
layer was thoroughly washed with water and
dried over MgSO4. After evaporation of the sol-
4.1.2.1. General method for the synthesis of H2-
(
)
tetrakis- 2,6 - dichloro-3-sulphonamido-phenyl
porphyrins 3–9. Batches of about 100–150 mg
Ž
Ž
.
vent, column chromatography silica-gel, Et2Or
0.078–0.117 mmol of 2 were refluxed in
.
Ž
.
AcOEt 2r1 afforded 9.0 g 25% of the TEG-
monododecyl ether TEG-OC12 as clear oil
CHCl3 in the presence of a 5–10 molar-equiv-
alents of the desired amine. The disappearance
of starting porphyrin was followed by TLC on
silica-gel, and the crude products were purified
by column chromatography followed by a crys-
tallization from CH2Cl2rhexane. Compound
3–9 were obtained in 50–80% yield and were
Ž
.
1
20
Ž
.
Ž
.
nD s1.451 . H NMR 300 MHz, CDCl3 :
Ž
.
Ž
.
.
ds0.80 3H, t 1.20–1.30 18H, br s , 1.55
Ž
Ž
.
Ž
2H, m , 2.78 1H, br t, D2O exchange , 3.40
.
Ž
.
2H, t , 3.50–3.70 16H, m .
This compound undergone the reactions re-
1
ported above in the case of the PEG350-OMe;
thus, in the sequence, it was reacted with
CH3SO2Cl in pyridine then with potassium ph-
thalimide in DMF and, as last, with hydrazine in
characterized by H NMR, MS-FABq and mo-
lar extinction coefficient in the visible range.
Ž
H2-tetrakis- 2,6-dichloro-3-N- octylsulphon-
.
Ž
amidophenyl porphyrin H2-TDClSO2-NHC8-

(
)
26
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
1
.
Ž
.
Ž
.
w
Ž
PP 3: H NMR 300 MHz, CDCl3 : dsy2.53
mass; UV–Vis CH2Cl2 : lmaxrnm ´r mmol
1
ly 419 296 .
Ž
Ž
.
Ž
.
Ž
.
.
x
Ž
.
2H, s 0.85 12H, t , 1.23–1.32 40H, m , 1.60
.
Ž
.
.
Ž
.
Ž
Ž
8H, m , 3.17 8H, m , 5.00 4H, m , 7.96 4H,
H2- tetrakis- 2,6- dichloro-3-N-tetraethylene-
glycol-monododecylether-sulphonamidophenyl
porphyrin H2-TDClSO2 NHTEG-OC12 PP 8:
q
.
Ž
.
d , 8.58 12H, sqd ; MS-FAB : mrz 1654
highest peak of molecular cluster; C76H90-
N8O8S4Cl8 requires 1650 as lowest isotope
Ž
.
Ž
1
Ž
.
H NMR 300 MHz, CDCl3 : dsy2.55 2H,
Ž
.
.
Ž
.
Ž
.
Ž
molecular mass; UV–Vis CH2Cl2 : lmaxrnm
s , 0.83 12H, t , 1.10–1.30 80H , 1.35–1.53
y
1
w
Ž
.
x
Ž .
419 283 .
Ž
Ž
.
.
Ž
.
.
´r mmol l
8H, m , 3.20–3.50 64H, m , 6.28 4H, t , 7.96
q
Ž
Ž
.
H2-tetrakis - 2,6 - dichloro-3-N,N-dibutylsul-
4H, d , 8.58 12H, sqd ; MS-FAB : 2583
.
Ž
phonamidophenyl porphyrin H2-TDClSO2-
N,NC4PP 4: H NMR 300 MHz, CDCl3 :
highest peak of molecular cluster; C124H186N8-
1
.
Ž
Ž
.
.
O24S4Cl8 requires 2578 as lowest isotope
Ž
.
.
Ž
Ž
.
dsy2.53 2H, s 0.90 12H, t , 1.20–1.30
molecular mass; UV–Vis CH2Cl2 : lmaxrnm
y
1
Ž
Ž
.
Ž
.
.
w
Ž
.
x
Ž .
420 235 .
8H, m , 1.45–1.53 8H, m , 3.35 8H, m , 5.00
´r mmol l
.
Ž
.
Ž
Ž
4H, m , 7.92 4H, d , 8.52 12H, sqd ; MS-
H 2-tetrakis- 2,6-dichloro-3-N, N-diethyl-
FABq: mrz 1654 highest peak of molecular
cluster; C76H90N8O8S4Cl8 requires 1650 as
lowest isotope molecular mass; UV–Vis
.
Ž
sulphonamidophenyl porphyrin H2-TDClSO2-
1
.
Ž
.
N,NC2 PP 9: H NMR 300 MHz, CDCl3 :
Ž
.
Ž
.
Ž
.
dsy2.54 2H, s 1.23 24H, t , 3.48 16H, m ,
7.94 4H, d , 8.57 12H, sqd ; MS-FAB :
mrz 1430 highest peak of molecular cluster;
C60H58N8O8S4Cl8 requires 1426 as lowest iso-
tope molecular mass; UV–Vis CH2Cl2 :
lmaxrnm ´r mmol l
y
1
q
Ž
.
w
Ž
.
x
Ž
.
Ž
.
Ž
.
CH2Cl2 : lmaxrnm ´r mmol l
H 2-tetrakis- 2,6-dichloro-3-N-hexadecyl-
sulphonamidophenyl porphyrin H2-TDClSO2-
NHC16PP 5: H NMR 300 MHz, CDCl3 :
dsy2.53 2H, s 0.85 12H, t , 1.23–1.32
104H, m , 1.60 8H, m , 3.20 8H, m , 4.96
419 285 .
Ž
.
Ž
1
.
Ž
Ž
.
Ž
.
y
1
Ž
.
.
w
Ž
.
x
Ž .
418 270 .
Ž
Ž
.
Ž
.
Ž
.
.
.
Ž
.
Ž
4H, m , 7.96 4H, d , 8.58 12H, sqd ; MS-
4.1.3. Synthesis of manganese-complexes of
porphyrins 3–9
Metallation of the free base porphyrins was
obtained refluxing the substrates in DMF in the
presence of a large excess of Mn OAc 25 .
The formation of the complexes was monitored
FABq: mrz 2104 highest peak of molecular
cluster; C104H154N8O8S4Cl8 requires 2098 as
lowest isotope molecular mass; UV–Vis
y
1
Ž
.
w
Ž
.
x
Ž
.
Ž
.
w
x
CH2Cl2 : lmaxrnm ´r mmol l
H2-tetrakis- 2,6-dichloro-3- N,N - dioctylsul-
phonamidophenyl porphyrin H2-TDClSO2-
N,NC8PP 6: H NMR 300 MHz, CDCl3 :
dsy2.52 2H, s 0.78–0.92 24H, m , 1.15–
1.40 80H, m , 1.40–1.65 16H, m , 3.30–3.40
419 241 .
2
Ž
.
Ž
Ž
.
by TLC silica-gel, CH2Cl2rEtOH 9r1 and by
UV–Vis spectroscopy. Catalysts Mn-3–Mn-9
were purified by column chromatography up to
a single spot and analyzed with MS-FABq and
spectrophotometrically.
1
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
16H, m , 7.92 4H, d , 8.52 12H, sqd ;
MS-FABq: mrz 2104 highest peak of molecu-
lar cluster; C104H154N8O8S4Cl8 requires 2098
as lowest isotope molecular mass; UV–Vis
Mn-3: MS-FABq: mrz 1707 highest peak of
molecular cluster; C76H88N8O8S4Cl8Mnq re-
quires 1703 as lowest isotope molecular mass;
y
1
y
1
Ž
.
w
Ž
.
x
Ž .
Ž
.
w
Ž
.x
CH2Cl2 : lmaxrnm ´r mmol l
H2-tetrakis- 2,6-dichloro-3- N- polyethylene-
glycol-monomethylether-sulphonamidophenyl
porphyrin H2-TDClSO2 NHPEG-OMePP 7: H
419 294 .
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
Ž
Ž
.
479 92 .
Mn-4: MS-FABq: mrz 1707 highest peak of
molecular cluster; C76H88N8O8S4Cl8Mnq re-
quires 1703 as lowest isotope molecular mass;
.
1
Ž
.
Ž
.
Ž
.
NMR 300 MHz, CDCl3 : dsy2.55 2H, s
y
1
Ž
.
Ž
.
Ž
Ž . w Ž
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
.x
3.25–3.72 124H, m , 6.28 4H, br t , 7.96 4H,
q
.
Ž
.
Ž .
478 115 .
d , 8.58 12H, sqd ; MS-FAB : 2495 highest
peak of molecular cluster; C104H146N8O36-
S4Cl8 requires 2490 as lowest isotope molecular
Mn-5: MS-FABq: mrz 2155 highest peak of
molecular cluster; C104 H152 N8O8 S4Cl8 Mnq

(
)
S. Banfi et al.rJournal of Molecular Catalysis A: Chemical 151 2000 17–28
27
requires 2151 as lowest isotope molecular mass;
reaction concentrations of catalyst, alkene,
y
1
4
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
and axial ligand become 3.3=10y M, 1.65
Ž
.
w
Ž
.x
1
3
479 85 .
=10y M and 3.3=10y M, respectively.
Ž
.
Mn-6: MS-FABq: mrz 2155 highest peak of
molecular cluster; C104H152N8O8S4Cl8Mnq re-
quires 2151 as lowest isotope molecular mass;
The solution was stirred for about 5 min, then
Ž
0.2 ml of the oxidant were added molar ratio
.
alkeneroxidants2.3 . The pH of the H2O2
aqueous phase was previously adjusted to 4.5
y
1
Ž
.
w
Ž
.x
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
Ž
.
Ž .
478 98 .
adding 8 mg of sodium benzoate A to 2 ml of
Mn-7: MS-FABq: 2547 highest peak of
molecular cluster; C104 H144 N8O36S4Cl8 Mnq
requires 2543 as lowest isotope molecular mass;
17.5% H2O2 molar ratio ArMn–Ps5 .
The mixture was stirred and samples of 0.1
ml were taken at different time and analysed by
G.C. Before injecting the organic phase in the
G.C. column, the samples were diluted with 0.4
ml of CH2Cl2, washed with distilled water and
dried with Na2SO4.
Ž
.
y
1
Ž
.
w
Ž
.x
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
Ž
.
478 80 .
Mn-8: MS-FABq: 2636 highest peak of
molecular cluster; C124 H184 N8O24S4Cl8 Mnq
requires 2631 as lowest isotope molecular mass;
y
1
Ž
.
w
Ž
.x
UV–Vis CH2Cl2 : lmaxrnm ´r mmol l
References
Ž
.
479 126 .
Mn-9: MS-FABq: MS-FABq: mrz 1483
highest peak of molecular cluster; C60-
H56N8O8S4Cl8Mn requires 1479 as lowest iso-
w x
Ž .
I. Tabushi, Coord. Chem. Rev. 86 1988 1.
1
2
3
w x
Ž
.
B. Meunier, Bull. Soc. Chim. France 578 1986 .
w x
D. Mansuy, P. Battioni, J.-P. Battioni, Eur. J. Biochem. 184
Ž
.
1989 267.
Ž
.
tope molecular mass; UV–Vis CH2Cl2 :
w x
w x
Ž .
4
5
D. Mansuy, Pure Appl. Chem. 59 1987 759.
y
1
Ž
.
w
Ž
.
x
Ž .
478 118 .
S. Quici, S. Banfi, Pozzi. G. Gazz. Chim. Italy 123 1993
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lmaxrnm ´r mmol l
w x
6
A.M.d’A. Rocha Gonsalves, M.M. Pereira, J. Mol. Catal.
Ž
.
113 1996 209.
w x
4.1.4. General method for alkene epoxidations
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Mn-9
7
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Ž
.
1997 251.
w x
8
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Ž
.
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Reactions were carried out in a 10 ml flask
equipped with a Teflon-lined screw cap and
magnetic stirrer, thermostatted at 0"0.28C with
circulating ethanol by a Haake F3 Cryostat;
stirring was maintained at 1300"50 rpm. The
flask was charged with the following CH2Cl2
solution:
w x
Ž
.
.
9
S. Banfi, F. Montanari, S. Quici, J. Org. Chem. 53 1988
2863.
w
w
x
Ž
10 S. Banfi, F. Montanari, S. Quici, J. Org. Chem. 54 1989
1850.
x
11 S. Banfi, F. Montanari, S. Quici, Recl. Trav. Chim. Pays-Bas.
Ž
.
109 1990 117.
w
w
w
x
Ž
.
12 T.G. Traylor, S. Tsuchiya, Inorg. Chem. 26 1987 1338.
x
Ž
.
13 D. Mansuy, Coord. Chem. Rev. 125 1993 129.
x
14 M.S. Chorghade, D. Dolphin, D. Dupre, D.R. Hill, E.C. Lee,
`
y
3
Ž .
Mn–P ;
Ž
.
a 1 ml of a 10
M solution of catalyst
T.P. Wijesekera, Synthesis 1321 1996 .
w
x
15 A.M.d’A. Rocha Gonsalves, R.A.W. Johnstone, M.M.
Ž
.
Ž
.
Pereira, J. Shaw, A.J.F.N. Sobral, Tetrahedron Lett. 32 1991
Ž .
b 1 ml of a 0.5 M solution of alkene,
1355.
Ž
.
containing ortho-dichlorobenzene 0.5 M as
w
x
16 S. Banfi, R. Mandelli, F. Montanari, S. Quici, Gazz. Chim.
Ž
.
Italy 123 1993 409.
Ž
internal standard molar ratio alkenerMn–P
w
w
x
Ž
.
17 A. Ghosh, J. Am. Chem. Soc. 117 1995 4691.
.
s500 ;
x
18 S. Banfi, A. Maiocchi, A. Moggi, F. Montanari, S. Quici, J.
Ž .
c 0.1 ml of a 0.1 M solution of N-hexyl-
Ž
.
Chem. Soc. Chem. Commun. 1749 1990 .
w
x
Ž . Ž
19 S. Banfi, F. Montanari, S. Quici, S.V. Barkanova, O.L.
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.
LrMn–Ps10 .
Ž
.
Lett. 36 1995 2317.
Ž .
d 0.9 ml of pure solvent to bring the total
w
x
20 M.D. Assis, A.J.B. Melo, O.A. Serra, Y. Iamamoto, J. Mol.
Ž
.
volume of the organic phase at 3 ml. The
Catal. 97 1995 41.

(
)
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x
Ž
.
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w
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x
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.
x
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.
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.
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.
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.
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w
x
x
31 F.A. Walker, M.-W. Lo, M.T. Ree, J. Am. Chem. Soc. 98
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.
Ž
.
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x
26 F. Montanari, S. Banfi, G. Pozzi, S. Quici, Oxygenation
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.
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Ž
.
x Ž .
33 J.S. Lindsey, R.W. Wagner, J. Org. Chem. 54 1989 828.