Cytochrome P450 Mimics
871±880
1
/18, v/v). Yield: 45 mg (85%) of Mn-2 as a green powder. R
CHCl
, 1/9, v/v) 0.7. FAB-MS: m/z: 1629 [M]. UV/Vis (CHCl
lge): 382 (4.60), 406 (4.56), 480 (4.87), 584 (3.83), 625 nm (4.00).
,10-Di(4-pyridyl)-15,20-di(4-hexadecyloxyphenyl)porphyrin
ese(iii) acetate was synthesized as described in the literature
1H,23H-5,10-di(4-pyridyl)-15,20-di(4-hexadecyloxyphenyl)porphyrin
100 mg) and manganese(iii) acetate (100 mg). Yield: 98 mg (94%) of
compound as a green powder. R (MeOH/CHCl
, 1/9, v/v) 0.15. UV/Vis
): lmax: 378, 403, 479, 581, 619 nm.
,10-Di(4-(methylpyridinium)-15,20-di(4-hexadecyloxyphenyl)-porphyrin
f
(MeOH/
After the cyclic voltamograms had been recorded, ferrocenecarboxylic acid
�
4
� 1
3
3
): lmax
was added to give a concentration of 5 Â 10 molL . The redox potential
(
of this compound (E1/2 0.275 V vs. SCCE, DE
p
62 mV and i
b
/i
f
1) was
measured, and the half-wave potentials are reported relative to this internal
standard.
5
mangan-
[
35]
from
2
(
Reduction experiments: The desired amounts of stock solutions of Rh-5,
manganese(iii) porphyrin, and DHP, DODAC, DPPA, or DPPC in
chloroform were mixed in a test tube. The solvent was evaporated under
a stream of nitrogen to leave a homogeneous film. This film was dissolved
in ethanol/tetrahydrofuran (100 mL; 1/1, v/v) and injected into water
f
3
(
CHCl
3
5
(
1.25 mL) at 758C. The suspension was purged with argon for 30 min and
manganese(iii) acetate ditosylate (Mn-3): Under a nitrogen atmosphere,
,10-di(4-pyridyl)-15,20-di(4-hexadecyloxyphenyl)porphyrin mangan-
injected into a cuvette containing an ethylmorpholine/sodium formate
buffer (1.25 mL) at 758C. The course of the reaction was monitored by
measuring the change of the absorbance in the UV/Vis spectrum (l): Rh-5
5
ese(iii) acetate (50 mg) and methyl tosylate (300 mg) were dissolved in a
mixture of toluene/acetonitrile (10 mL, 2/1, v/v). The reaction mixture was
stirred at 808C for 16 h. After cooling to room temperature, the reaction
mixture was poured over a glass filter covered with silica. After washing
with acetone (50 mL) to remove excess methyl tosylate, Mn-3 was isolated
(
522), Mn-1 (435), Mn-2 (440), Mn-3 (453), Mn-4 (446 nm).
Conditions: Rhodium reduction: 72mm of Rh-5, 926mm of surfactant in
ethylmorpholine (50mm)/sodium formate (150mm) buffer. The resulting
I
by elution with (MeOH/CHCl
a dark green powder. R (MeOH/CHCl
180 [M � 2tos � acetate]. UV/Vis (CHCl
4.51), 476 (5.16), 580 (4.08), 620 nm (3.87).
3
, 1/1, v/v). Yield: 40 mg (61%) of product as
, 1/9, v/v) 0.1. FAB-MS: m/z:
): lmax (lge): 380 (4.61), 404
curves were fitted with the following first-order equation [Rh ]
t
I
I
� kt
f
3
[Rh ]max � [Rh ]max
e .
1
(
3
pH Experiments: 7.2mm of Rh-5, 910mm surfactant in ethylmorpholine
(
50mm)/sodium formate (150mm) buffer adjusted to the desired pH value
5
,10,15,20-Tetra(4-pyridyl)porphyrin manganese(iii) acetate: The com-
with a concentrated sodium hydroxide solution. The pH curves were fitted
[36]
I
I
pound was synthesized as described in the literature,
starting from
with the equation [Rh ]
t
[Rh ]max/(K
a
[H ] 1).
2
1H,23H-5,10,15,20-tetra(4-pyridyl)porphyrin (50 mg) and manganese(iii)
acetate (300 mg). Yield: 72% of product as a green powder. R (MeOH/
CHCl ): lmax: 368, 396, 473, 581, 616 nm.
, 1/9, v/v) 0.05. UV/Vis (CHCl
,10,15,20-Tetra(4-(1-methylpyridinium))porphyrin manganese(iii) penta-
Formate experiments: 2.4mm of Mn-1, 12mm of Rh-5, 910mm of surfactant in
ethylmorpholine (50mm)/sodium formate (varied between 0.016 and
f
3
3
0
.150m) buffer (pH 7.0).
5
Temperature experiments: 2.4mm of Mn-1, 7.2mm of Rh-5, 910mm of
surfactant in ethylmorpholine (50mm)/sodium formate (150mm) buffer
(pH 7.0); T was varied between 258C and 658C.
[
36]
chloride (Mn-4) was synthesized according to a literature procedure
from 5,10,15,20-tetra(4-pyridyl)porphyrin manganese(iii) acetate (50 mg)
and methyl tosylate (400 mg), and converted to the corresponding chloride
salt by ion exchange chromatography. Yield: 52 mg (72%) of Mn-4 as a
Experiments with rhodium complexes: 2.4mm of Mn-1, 2.4nmm of Rh-5 (n
Rh/Mn molar ratio), 910mm of surfactant in ethylmorpholine (50mm)/
sodium formate (150mm) buffer (pH 7.0), T 488C.
�
�
dark green powder. FAB-MS: m/z: 766 [M � 4Cl ], 731 [M � 5Cl ]. UV/
Vis (EtOH): lmax (lge): 372 (4.12), 396 (4.05), 461 (4.55), 569 (3.57), 620 nm
Oscillation experiment: 2.4mm of Mn-1, 24.0mm of Rh-5, 910mm of DPPC in
ethylmorpholine (50mm)/sodium formate (150mm) buffer (pH 7.0), T
(
3.87).
Vesicle preparation: Aliquots of stock solutions of manganese(iii) porphyr-
in, Rh-5, and surfactant, calculated to give the desired concentrations, were
mixed in a test tube. The solvent was evaporated under a stream of nitrogen
to give a homogeneous thin film. This film was dissolved in ethanol/THF
4
88C.
Epoxidation experiments: Final conditions: 2.4mm of Mn-1, 2.4nmm of Rh-
(n Rh/Mn molar ratio), 3.5mm of N-methylimidazole and 910mm of
surfactant in ethylmorpholine (50mm)/sodium formate (250mm) buffer
pH 7.0), 200mm of substrate. The 100 mL of solution containing all
5
(
100 mL, 1/2, v/v). Half of the solution was injected into an ethylmorpho-
(
line/formate buffer solution (5 mL) at a temperature above the phase-
transition temperature of the surfactant bilayer: for DODAC T
for DPPC T
components was directly injected into a buffered solution (2.5 mL) above
the phase-transition temperature of the vesicle bilayers. After 1 min the
substrate was injected, and the reaction mixture was analyzed by taking
[
37]
c
c
388C,
728C.
[12]
[38]
[39]
c
428C, for DPPA T
c
588C, and for DHP T
Incorporation experiments: The efficiency of incorporation of the catalyst
in the vesicles was measured by gel permeation chromatography (GPC) in
combination with UV/Vis spectroscopy. Vesicle solutions were prepared as
described above and were passed over a Sephadex G50 column with
ethylmorpholine buffer as the eluent. The fractions were collected and the
UV/Vis absorption spectra were measured to calculate the manganese(iii)
porphyrin, Rh-5, and amphiphile concentrations.
0
.2 mL aliquots, to which was added 0.1 mL of diethyl ether containing
mesitylene as an internal standard. This mixture was vortexed and
centrifuged. After phase separation, a 5 mL sample was taken from the
diethyl ether layer and analyzed by GLC (temperature program 708C
� 1
(
2 min), 108Cmin , 2208C (2 min)). Reaction products were identified by
GC/MS and by comparison with authentic samples.
Electron microscopy: For the visualization of the vesicles, the negative
staining method was used. A droplet of a vesicle solution was placed on a
Formvar-coated copper grid which had first been made hydrophilic by
exposure to an argon plasma for 2 min. After allowing adsorption on the
grid to proceed for 2 min, the solution was drained with filter paper and the
samples were stained with an aqueous uranyl acetate solution (1 wt%)
which was removed after 1 min.
Acknowledgments: The authors thank Dr. J. H. van Esch, Dr. M. J. B.
Hauser (Universität Würzburg, Germany) and M. C. P. F. Driessen for help
and stimulating discussions. This work was supported by the Dutch
Foundation for Chemical Research (SON) with financial aid from the
Dutch Organization for Scientific Research (NWO).
Received: October 13, 1997 [F853]
Differential scanning calorimetry: Cups containing about 10 mg of material
were placed in the DSC apparatus, and heating and cooling scans were
[
[
1] F. P. Guengerich, J. Biol. Chem. 1991, 266, 10019.
2] I. Tabushi, Coord. Chem. Rev. 1988, 86, 1.
�
1
recorded with a scan rate of 28Cmin
.
Cyclic voltammetry: All measurements were carried out in water with a
basal-plane pyrolytic graphite electrode as the working electrode, which
was polished with alumina, rinsed with water, and cleaned in a bath-type
sonicator for 1 min before use. The reference electrode was a sodium-
saturated calomel electrode (SSCE), which was separated from the solution
by a salt bridge of similar composition and pH; the auxiliary electrode was
a platinum electrode. In a typical experiment, 4 mL of an ethylmorpholine
buffered (50mm, pH 7.0) vesicle solution of Rh-5 and surfactant was placed
in the electrochemical cell, and the solution was purged with nitrogen for
[3] a) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman,
Science 1993, 261, 1404; b) B. Meunier, Chem. Rev. 1992, 92, 1411; c) D.
Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 314; d) S. E. J. Bell,
P. R. Cooke, P. Inchley, D. R. Leanord, J. R. Lindsay Smith, A.
Robbins, J. Chem. Soc. Perkin Trans. 2 1991, 549.
[4] a) J. T. Groves, T. E. Nemo, R. S. Meyers, J. Am. Chem. Soc. 1979, 101,
1032; b) C. K. Chang, M.-S. Kuo, ibid. 1979, 101, 3413; c) D. Mansuy, P.
Battioni, J.-P. Renaud, J. Chem. Soc. Chem. Commun. 1984, 1235;
d) P. N. Balsubramanian, A. Sinha, T. C. Bruice, J. Am. Chem. Soc.
1987, 109, 1456; e) R. F. Parton, I. F. J. Vankelecom, M. J. A. Cassel-
man, C. P. Bezoukhanova, J. B. Uytterhoeven, P. A. Jacobs, Nature
�
1
20 min. Unless otherwise indicated, the scan rate was 100 mVs . A
nitrogen stream was passed over the solution during the measurements.
Chem. Eur. J. 1998, 4, No. 5
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