A new insight into the catalytic decomposition of ethyl diazoacetate in the presence of meso-tetraarylporphyrin (=5,10,15,20-tetraaryl-21H,23H-porphine) complexes

Article abstract of DOI:10.1002/hlca.200890247

The decomposition of ethyl diazoacetate by several catalysts in the presence of meso-tetraarylporphyrin complexes with different electronic features was evaluated. The distribution of the obtained products (chlorins, bacteriochlorins, isobacteriochlorins, and porphyrin derivatives resulting from C-H insertion and Buechner ring expansion) is dependent on the catalyst and on the electronic features of the meso-aryl groups.

Full text of DOI:10.1002/hlca.200890247

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Helvetica Chimica Acta – Vol. 91 (2008)
A New Insight into the Catalytic Decomposition of Ethyl Diazoacetate
in the Presence of meso-Tetraarylporphyrin (¼ 5,10,15,20-Tetraaryl-21H,23H-
porphine) Complexes
by Ana T. P. C. Gomesa), Raquel A. C. Lea˜oa)b), Cristina M. A. Alonsoa), Maria G. P. M. S. Nevesa),
Maria A. F. Faustinoa), Augusto C. Tome´ a), Artur M. S. Silvaa), Sergio Pinheiroa)b),
Maria Cecꢀlia B. V. de Souzab), Vꢀtor F. Ferreirab), and Jose´ A. S. Cavaleiro*a)
a) Department of Chemistry, University of Aveiro, P-3810-193 Aveiro
(phone: þ 351234370717; fax: þ 351234370084; e-mail: jcavaleiro@ua.pt)
b
ˆ
´
) Departamento de Quꢀmica Organica, Universidade Federal Fluminense, 24020-150, Niteroi, RJ, Brazil
The decomposition of ethyl diazoacetate by several catalysts in the presence of meso-tetraarylpor-
phyrin complexes with different electronic features was evaluated. The distribution of the obtained
products (chlorins, bacteriochlorins, isobacteriochlorins, and porphyrin derivatives resulting from CꢀH
insertion and Bꢀchner ring expansion) is dependent on the catalyst and on the electronic features of the
meso-aryl groups.
Introduction. – Porphyrins have important applications in several scientific areas,
namely in medicine, catalysis, electronics, solar-cell production, etc. The functionaliza-
tion of porphyrins at the b-pyrrolic positions (C(2), C(3), C(7), C(8), C(12), C(13),
C(17), and C(18)) merits considerable attention due to the diversity of structural
features that can be introduced into the macrocycle. Of special importance are those
leading to reduced porphyrins, mainly chlorins (¼ 7,8-dihydro-21H,23H-porphines) and
bacteriochlorins (¼ 7,8,17,18-tetrahydro-21H,23H-porphines), and p-extended por-
phyrin derivatives, which show strong light absorption near or above 600 nm, a
requirement for a photosensitizer to be used in PDT (photodynamic therapy) [1]. Over
the past years, we and others have been developing new methods for reaching those
types of compounds, namely Diels – Alder reactions [2], 1,3-dipolar cycloadditions
[3][4], and electrocyclization reactions [5].
In the early 1970s, Callot reported the functionalization of (meso-tetraphenylpor-
phyrinato)zinc(II) (meso positions ¼ C(5), C(10), C(15), and C(20)) by addition of
carbenes generated from several diazoacetates catalyzed by CuCl [6]. These reactions
afforded, after demetallation, a mixture of isomeric cyclopropa-fused chlorins, trace
amounts of bacteriochlorins, and N-alkylated products. It is relevant to note that no
isobacteriochlorins (¼12,13,17,18-tetrahydro-21H-22H-porphines) were isolated from
those reactions. Having in mind that biologically significant compounds can be
obtained along such procedures, and since Callot studied these reactions with only one
meso-tetraarylporphyrin complex and one catalyst, we decided to revisit this subject
using three meso-tetraarylporphyrin complexes with different electronic features and
ꢁ 2008 Verlag Helvetica Chimica Acta AG, Zꢂrich

Helvetica Chimica Acta – Vol. 91 (2008)
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several catalysts. Ethyl diazoacetate (EDA) was used as the precursor of the carbene.
In recent years, several catalysts based on RhII, CuI, CuII, and PdII complexes have
been used to promote the decomposition of diazo compounds in the presence of
alkenes [7][8]. Depending on the catalyst used, a different reactivity and selectivity of
the short-lived transition-metal – carbene intermediates is observed. Furthermore,
porphyrinatoiron, -rhodium, and -osmium complexes have also been reported as
catalysts for the decomposition of diazo compounds [9]. For our studies, we selected
the following catalysts: CuCl, [Cu(OTf)(C6H6)], [Cu(OTf)2], [Rh2(OAc)4],
[Pd(OAc)2], and chloro[meso-tetrakis(2,6-dichlorophenyl)porphyrinato]iron(III)
([FeCl(tdcpp)]). Three meso-tetraarylporphyrin complexes with different electronic
features were used as substrates: (meso-tetraphenylporphyrinato)zinc(II) (1a), [meso-
tetrakis(3-methoxyphenyl)porphyrinato]zinc(II) (1b) and [meso-tetrakis(2,3,4,5,6-
pentafluorophenyl)porphyrinato]zinc(II) (1c). While in 1a the meso-phenyl groups
have no substituents, in 1b there are electron-releasing groups and in 1c electron-
withdrawing atoms.
Results and Discussion. – Reactions of the Porphyrins with EDA. Reactions of
porphyrins 1a – c with EDA (10 equiv. added dropwise) were performed in dry CH2Cl2
at 408 under N2, in the presence of the selected catalyst. The slow addition of EDA
allowed the formation of the isolated products in reliable yields and minimized the
competitive formation of carbene dimers. Since copper and palladium catalysts are
typically less active than RhII and Fe complexes [7][9], 2 mol-% (relative to EDA) of
the catalysts based on copper and palladium were used instead of 1 mol-% in the case
of [Rh2(OAc)4,] and [FeCl(tdcpp)]. No improvement in the outcome of the reactions
was observed when the catalysts were used in higher proportions. Depending on the
catalyst, these reactions afforded monoadducts 2a – c and 3a – c, bis-adducts 6a – c and
7c, products 4a – c resulting from the CꢀH insertion in one b-pyrrolic position, and
products 5a,b resulting from a Bꢀchner expansion of one meso-aryl group (Schemes 1
and 2).
We started our experiments by repeating Callotꢃs work (porphyrin 1a, EDA, and
CuCl, but with CH2Cl2 as the solvent). Our results were similar to those reported, both
in terms of products obtained and yields (Table 1, Entry 3). Taking these results into
consideration, we decided to verify if porphyrin 1a behaves similarly in the presence of
other catalysts.
From Table 1, one can see that [Rh2(OAc)4], [Cu(OTf)2], CuCl, and
[Cu(OTf)(C6H6)] are the catalysts that promote higher conversions of porphyrin 1a
(Entries 1 – 4). However, we can observe that Cu-based catalysts are more selective for
the cyclopropanation reaction affording preferentially the trans-chlorin 2a1). The same
1
)
The cis and trans descriptors are used for simplicity. The cis isomer is the one with HꢀC(2),
HꢀC(21), and HꢀC(3) in the same plane, while in the trans isomer HꢀC(21) is in a different plane
than the other two H-atoms. In the Exper. Part, for the assignment of the configuration of the
cyclopropane derivatives, we use the IUPAC Recommendations (1993 and 1999) concerning the
configuration of cycloalkane compounds with more than two substituents, applied to the
relationship of these H-atoms; systematic fusion names are also given in the Exper. Part.

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Scheme 1
stereoselectivity is also observed in the reactions catalyzed by [Pd(OAc)2] and
[FeCl(tdcpp)], but with lower yields (Entries 5 and 6). It is interesting to note that the
RhII catalyst is the only one that promotes the formation of the CꢀH insertion product
4a (Entry 1). The Bꢀchner expansion product 5a is obtained in the presence of
[Rh2(OAc)4] and, in minor amounts, when [Cu(OTf)(C6H6)] and [FeCl(tdcpp)] are
used (Entries 4 and 6). In the reaction catalyzed by CuCl, we also observe the

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Scheme 2
formation, in small amounts, of the bacteriochlorin 6a2) resulting from the cyclo-
propanation of two opposite pyrrole units (Entry 3).
The reactivity of porphyrin 1b with EDA in the presence of the various catalysts has
a similar profile to the one observed for porphyrin 1a. In this case, the catalysts
The bacteriochlorins 6a – c and the isobacteriochlorin 7c give only one spot on TLC. The 1H-NMR
spectrum of 7c shows that it is a mixture of cis and trans isomers (with respect to the porphyrin
macrocycle). Probably compounds 6a – c are also isomer mixtures, but due to the very low amounts
isolated, it was not possible to confirm it by NMR.
2
)

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Table 1. Conversion and Selectivity of the Products Obtained from the Reaction of 1a with EDA in the
Presence of Several Catalysts
Entry
Catalysta)
Conversion [%]
Selectivity [%]
2a
3a
4a
5a
6ab)
1
2
3
4
5
6
1% [Rh2(OAc)4]
2% [Cu(OTf)2]
2% CuCl
2% [Cu(OTf)(C6H6)]
2% [Pd(OAc)2]
1% [FeCl(tdcpp)]
63.0
63.2
70.3
66.0
44.1
14.5
21.1
28.2
28.0
20.2
20.2
25.7
18.4
2.7
5.1
1.2
1.8
5.7
25.4
21.1
–
–
1.2
–
19.1
–
–
2.3
–
–
–
–
–
–
–
–
a) % Relative to EDA. b) Characterized only by UV/VIS and MS.
[Rh2(OAc)4] and CuCl (Table 2, Entries 1 and 3) are the ones that promote the highest
conversion of the porphyrin, but the Cu-based catalysts are the most selective for the
cyclopropanation products, affording predominantly the trans isomer 2b (Entries 2 – 4).
This stereoselectivity is also observed when [Pd(OAc)2] is used (Entry 5).
Table 2. Conversion and Selectivity of the Products Obtained from the Reaction of 1b with EDA in the
Presence of Several Catalysts
Entry
Catalysta)
Conversion [%]
Selectivity [%]
2b
3b
4b
5b
6bb)
1
2
3
4
5
6
1% [Rh2(OAc)4]
2% [Cu(OTf)2]
2% CuCl
2% [Cu(OTf)(C6H6)]
2% [Pd(OAc)2]
1% [FeCl(tdcpp)]
62.0
33.8
70.0
51.7
45.9
24.3
24.9
26.5
25.9
26.2
25.7
11.3
21.8
2.7
2.6
1.7
1.1
3.7
24.9
27.5
–
–
5.2
9.8
7.5
–
–
1.1
–
–
–
–
–
–
–
–
a) % Relative to EDA. b) Characterized only by UV/VIS and MS.
The outcome is different when the catalytic decomposition of EDA is performed in
the presence of porphyrin 1c (Scheme 2 and Table 3). From Table 3, it is obvious that
the highest conversions of porphyrin 1c are obtained in the presence of the Cu-based
catalysts CuCl and [Cu(OTf)2] (Entries 2 and 3). In the case of [Cu(OTf)(C6H6)], a low
conversion is observed, but the selectivity for chlorin 2c is quite high (85%; Entry 4).
The preference for the trans-chlorin 2c is also observed with the two former catalysts
(Entries 2 and 3). However, the CuCl is especially interesting because it also leads to
the formation of isobacteriochlorin 7c in remarkable yield (Entry 3). This isobacterio-
chlorin, which is a mixture of two diastereoisomers 7c1 and 7c2 (Fig. 1), results from
the bis-cyclopropanation of two adjacent pyrrole units. Compound 7c is also obtained
when the reactions are carried out in the presence of [Cu(OTf)2], [Cu(OTf)(C6H6)],
and [Pd(OAc)2] (Entries 2, 4, and 5). The formation of isobacteriochlorins is not
observed when porphyrins 1a and 1b are used. With CuCl, the bacteriochlorin 6c is also
detected but only in vestigial amounts (Entry 3). These results show that the site

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Fig. 1. Structures of the isobacteriochlorins 7c1 and 7c2
Table 3. Conversion and Selectivity of the Products Obtained from the Reaction of 1c with EDA in the
Presence of Several Catalysts
Entry
Catalysta)
Conversion [%]
Selectivity [%]
2c
3c
4c
6c
7c
1
2
3
4
5
6
1% [Rh2(OAc)4]
2% Cu(OTf)2
2% CuCl
2% [Cu(OTf)(C6H6)]
2% [Pd(OAc)2]
1% [FeCl(tdcpp)]
31.9
40.0
65.8
23.9
20.1
13.9
11.0
38.3
41.0
85.0
19.1
39.6
1.8
8.7
–
–
–
–
–
–
–
6.5
39.5
< 1b)
9.5
< 1b)
2.7
< 1b)
< 1b)
< 1b)
< 1b)
–
–
–
–
–
a) % Relative to EDA. b) Characterized only by UV/VIS and MS.
selectivity of the bis-addition of carbenes to the porphyrin macrocycle is controlled by
the electronic features of the meso-aryl groups.
With porphyrin 1c, the RhII catalyst (Table 3, Entry 1) is the least efficient catalyst.
It leads to trans-chlorin 2c and cis-chlorin 3c and to the CꢀH insertion product 4c with
lower selectivity; a number of other minor unidentified products are also formed. As
expected, the Bꢀchner expansion product is not observed for this porphyrin.
Surprisingly, when the porphyrin complex [FeCl(tdcpp)] is used as the catalyst, the
starting porphyrins 1a – c are recovered for the most part and, as a consequence, the
resulting products (chlorins and Bꢀchner expansion derivatives) are isolated in very
low yields. The low yields obtained are unexpected since this catalyst was successfully
used in the decomposition of diazo compounds for the cyclopropanation of styrenes
[9a]. The low efficiency of this catalyst in the functionalization of porphyrins 1a – c is
probably due to its reaction with the generated carbene or due to the conversion of the
iron – carbene intermediate into an inactive species. To confirm this hypothesis, we
performed the reaction of [FeCl(tdcpp)] with EDA under the same conditions as those
used for the other reactions. The UV/VIS spectrum of the green reaction mixture did
not show any absorption band typical of chlorins, but its MS showed a molecular ion
corresponding to [FeCl(tdcpp)] plus a carbene unit ([M þ H]þ at m/z 1061). Probably,

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the adduct results from the insertion of a carbene into the FeꢀN bond, as already
described [10].
Mechanistic Considerations and Spectroscopic Features of the Products. According
to the literature, the decomposition of the diazo compounds involves the formation of
the metal – carbene intermediate 8 (Scheme 3) [11 – 14]. The interaction of a C¼C
bond of the macrocycle with the electrophilic center of the metal – carbene
intermediate leads to the transient intermediate 9 which can cyclize to chlorins 2 and
3 (Route A) or rearrange to the CꢀH insertion products 4 (Route B). The catalyst is
regenerated in both cases.
Scheme 3
The formation of products 4 from chlorins 2 and 3, by a cyclopropane-ring-opening
reaction, was considered. However, heating solutions of the trans- and cis-chlorins 2a
and 3a with [Rh2(OAc)4] in refluxing CH2Cl2 for 24 h does not lead to the formation of

Helvetica Chimica Acta – Vol. 91 (2008)
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4a. This indicates that the reaction involved in the conversion of intermediate 9 into
chlorins 2 and 3 is irreversible.
The formation of the Bꢀchner expansion products occurs by a concerted [2 þ 2]
cycloaddition reaction between the metal – carbene intermediate and one of the meso-
aryl groups. Elimination of the catalyst, and electrocyclic ring opening of the
intermediate 11 leads to the products 5 (Scheme 4) [15]. The higher yield of the
Bꢀchner expansion product 5b, relatively to the analogous 5a, is due to the presence of
a methoxy substituent in the meso-aryl groups. In opposition, the deactivation on the
meso-aryl rings by the F-atoms in porphyrin 1c prevents the formation of the Bꢀchner
expansion product.
Scheme 4
1
The structures of the new compounds were assigned on the basis of their H- and
13C-NMR and UV/VIS spectra; the molecular formulas of the new compounds were
confirmed by HR-MS. All new porphyrinato-, chlorinato-, isobacteriochlorinato-, and
bacteriochlorinatometal derivatives show the typical UV/VIS spectra of such systems.
All chlorin derivatives 2a – c and 3a – c have analogous NMR spectra, showing
similar multiplicities and chemical shifts for the signals related to the resonance of the
six b-pyrrolic H-atoms, typically two d and one s. The trans- and cis-cyclopropane
isomers were distinguished by the coupling constant between the three H-atoms of the
cyclopropane ring (HꢀC(2), HꢀC(3), and HꢀC(21)).
Due to the symmetry of 2a – c and 3a – c, the s that appears between d(H) 8.28 and 8.50 is assigned to
the resonance of HꢀC(12) and HꢀC(13). The d that occur between d(H) 8.50 and 8.60 and between
d(H) 8.00 and 8.37 are assigned to the resonance of HꢀC(8) and HꢀC(17), and to HꢀC(7) and

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Helvetica Chimica Acta – Vol. 91 (2008)
HꢀC(18), resp. These attributions are established by the NOESY correlations between the signals of the
Ho-atoms of ArꢀC(10) and ꢀC(15) and the signals of HꢀC(8) and HꢀC(17), and of HꢀC(12) and
HꢀC(13). In the case of the trans-cyclopropanes 2a – c, the cyclopropane H-atoms give rise to a 3J of ca.
3
2.8 Hz, while in the cis-isomers 3a – c J is ca. 8.2 Hz.
The ESI-MS of the isobacteriochlorin mixture 7c1/7c2 (Fig. 1) shows a peak at m/z
1209 ([M þ H]þ), corresponding to the ꢄadditionꢃ of two carbene units to porphyrin 1c.
The 1H-NMR spectrum of 7c1/7c2 is relatively complex and shows duplicated signals in
a proportion of 2 :1. From the 19F-NMR spectrum it can be concluded that 7c1 is the
major diastereoisomer.
In the 1H-NMR spectrum of 7c1/7c2, we can observe the presence of two d at d(H) 7.62 and 7.69 due
to the resonances of the b-pyrrolic H-atoms HꢀC(12) and HꢀC(18), and HꢀC(13) and HꢀC(17), resp.,
of the major diastereoisomer (3J ¼ 4.4 Hz). For the minor diastereoisomer, the resonances of the same b-
pyrrolic H-atoms occur at d(H) 7.60 and 7.97 as two d (3J ¼ 4.3 Hz). The resonances of the MeCH2
protons appear as two t at d(H) 1.29 (3J ¼ 7.0 Hz) for the major diastereoisomer and at d(H) 1.30 (3J ¼
7.2 Hz) for the minor one; the resonances of the MeCH2 protons appear as a m at d(H) 4.22 – 4.28. The d
at d(H) 3.89 can be attributed to HꢀC(2), HꢀC(3), HꢀC(7), and HꢀC(8) of the major
diastereoisomer. The corresponding coupling constant (3J ¼ 2.6 Hz) supports the trans configuration of
both cyclopropane rings. The resonances of HꢀC(2) and HꢀC(8), and of HꢀC(3), and HꢀC(7) of the
minor diastereoisomer appear as four d at d(H) 3.86 (3J ¼ 2.9 Hz), 3.87 (3J ¼ 2.6 Hz), 3.94 (3J ¼ 2.6 Hz),
and 3.95 (3J ¼ 2.9 Hz), with 3J values confirming the trans configuration in both cyclopropane rings. The
signals of HꢀC(21) and HꢀC(71) appear at d(H) 1.44 (t, 3J ¼ 2.6 Hz) for the major diastereoisomer and
at d(H) 1.32 – 1.40 (m) for the minor one.
The structures of products 4a – c were deduced mainly from the analysis of their
1H-NMR spectra. These spectra reveal the resonances of only seven b-pyrrolic H-
atoms.
The signal of HꢀC(3) of 4a – c appears as a s in the range d(H) 8.79 – 8.89. The other signals appear
as a m between d(H) 8.90 and 8.99 and as two d between d(H) 8.87 and 8.92 and between d(H) 8.69 and
8.77 with the same coupling constant (J ¼ 4.6 Hz). The aliphatic region shows one s between d(H) 3.97
and 4.30 due to CH2(21). The q and the t (J ¼ 7.1 Hz) of the Et group appear between d(H) 4.12 and 4.16
and between d(H) 1.22 and 1.26, resp.
The 1H-NMR spectra of products 5a and 5b (Fig. 2) are consistent with structures
resulting from Bꢀchner expansion reactions.
Fig. 2. Structures of the Bꢂchner expansion products 5a and 5b

Helvetica Chimica Acta – Vol. 91 (2008)
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The eight b-pyrrolic H-atoms of 5a,b appear between d(H) 8.90 and 9.16 as two d and one m. The
aryl groups at the meso positions 10, 15, and 20 give rise to a m between d(H) 7.72 and 8.22. The H-atoms
of the cycloheptatrienyl group are unequivocally assigned by means of 2D-COSY experiments. In the
3
3
case of 5a, these H-atoms appear at d(H) 7.51 (d, J ¼ 6.0 Hz, Ha), 6.77 (dd, J ¼ 6.0, 9.1 Hz, Hb), 5.69
(ddd, 4J ¼ 1.3, 3J ¼ 6.0, 9.1 Hz, Hc), 3.37 (t, 3J ¼ 6.0 Hz, Hd), and 5.33 (ddd, 4J ¼ 1.3, 3J ¼ 6.0, 9.1 Hz, He).
The m between d(H) 7.25 and 7.50 is attributed to Hf although this signal is overlapped with the signal of
CH2Cl2. The q and the t at d(H) 4.42 and 1.34 (J ¼ 7.1 Hz), resp., are assigned to the Et group. The
cycloheptatrienyl protons of 5b appear at d(H) 6.56 (s, Ha), 4.13 (d, 3J ¼ 7.5, Hb), 7.19 (dd, 3J ¼ 7.5, 9.7 Hz,
Hc), 6.78 (dd, 3J ¼ 5.5, 9.7 Hz, Ha), and 7.19 (d, 3J ¼ 5.5 Hz, He), and the Et group gives rise to a q at d(H)
4.46 and a t at d(H) 1.42 (J ¼ 7.1 Hz ) .
Conclusions. – The study of the efficiency of several catalysts in the decomposition
of EDA in the presence of porphyrin complexes 1a – c shows that the distribution of the
products is dependent on the catalyst and on the electronic features of the meso-aryl
substituents at the tetrapyrrole macrocycle. The CuCl is the most selective catalyst for
the cyclopropanation reaction, affording predominantly the trans monoadduct of the
three porphyrin complexes used. In the presence of this catalyst, 1c is the most reactive
one. Its reaction with EDA gives reasonable yields of the trans-chlorin 2c and of the
isobacteriochlorin 7c. The cyclopropanation of tetrapyrrole macrocycles through the
catalytic decomposition of diazo compounds allows the synthesis of reduced porphyrins
that absorb at l values higher than 600 nm, an important structural requirement for a
good photosensitizer in PDT.
Amongst the studied catalysts, [Rh2(OAc)4] is the only one that catalyzes the CꢀH
insertion of carbene into the b-positions of the porphyrin macrocycle. This insertion
reaction can be considered a new approach for the functionalization of meso-tetra-
arylporphyrins.
ˆ
Thanks are due to the FundaÅa˜o para a Ciencia e a Tecnologia (FCT), FEDER, and the GRICES-
CAPES collaborative programme for funding this work. A. T. P. C. G. and C. M. A. A. thank,
respectively, the Aveiro Organic Chemistry Research Unit and FCT (SFRH/BPD/8375/2002) for their
research grants. Also R. A. C. L. and S. P. thank CAPES for their travelling grants to Aveiro.
Experimental Part
General. meso-Tetraarylporphyrins (¼ [5,10,15,20-tetraaryl-21H,23H-porphinato(2ꢀ)-kN21,kN22,
kN23,kN24]zinc) 1a – 1c and chloro[5,10,15,20-tetrakis(2,6-dichlorophenyl)-21H,23H-porphinato(2ꢀ)-
kN21,kN22,kN23,kN24]iron were prepared according to [16][17]. EDA and the remaining catalysts were
acquired from Sigma – Aldrich (Spain) and were used as received. The CH2Cl2 used as solvent of the
reactions was distilled over CaH2. Flash chromatography (FC): silica gel (SiO2; 230 – 400 mesh). Prep.
TLC: 20 ꢁ 20 cm glass plates coated with silica gel (1 mm thick). Anal. TLC: sheets precoated with silica
gel (SiO2; Merck 60, 0.2 mm thick). UV/VIS Spectra: Shimadzu UV-2501-PC spectrophotometer; in
CHCl3; lmax (log e) in nm. 1H-, 13C-, and 19F-NMR Spectra: Bruker Avance-300 spectrometers at 300.13,
75.47, and 282.38 MHz, resp., or Bruker Avance-500 spectrometer at 500.13 and 125.77 MHz for 1H and
13C, resp.; CDCl3 as solvent and SiMe4 as internal reference; chemical shifts d in ppm and coupling
1
constants J in Hz; unequivocal H assignments by 2D-COSY and NOESY experiments (mixing time
800 ms); 13C assignments by 2D-HSQC and HMBC experiments (delay for long-range J(C,H) optimized
for 7 Hz). MS and HR-MS: VG AutoSpec-M spectrometer; CHCl3 as solvent and 3-nitrobenzyl alcohol
(NBA) as matrix; in m/z (rel. %).
Reactions of Porphyrin Complexes 1a – c with EDA: General Procedure. EDA (10 equiv.) was added
dropwise by syringe during 7 h to a soln. of the porphyrin complex (50 mg) and the selected catalyst in

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dry CH2Cl2 (6 ml) at 408 under N2. The mixture was further stirred at 408 for 12 h. The solvent was then
evaporated and the residue fractionated by FC (SiO2), CH2Cl2/hexane in adequate proportions). The
fractions obtained were purified by prep. TLC (AcOEt/1:4).
[(2r,21t,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetraphenyl-2,3-dihydrocyclopropa[b]porphyrinato]zinc-
(II)1) (¼ [Ethyl (1a,1aa,19aa)-1a,19a-Dihydro-3,8,13,18-tetraphenyl-1H,20H,22H-cyclopropa[b]por-
phine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 2a). UV/VIS (CHCl3): 420 (5.79), 524 (3.67), 518
(4.08), 585 (4.18), 617 (4.74). 1H-NMR (500.13 MHz, CDCl3): 1.25 – 1.32 (m, MeCH2, HꢀC(21)); 4.23 (q,
J ¼ 7.1, MeCH2); 4.41 (d, J ¼ 2.7, HꢀC(2), HꢀC(3)); 7.62 – 7.70 (m, 12 H, Hm (Ph), Hp (Ph)); 7.85 – 7.86
(m, 2 Ho (PhꢀC(5) and ꢀC(20)); 8.03 – 8.05 (m, 2 Ho (PhꢀC(10) and ꢀC(15)); 8.09 – 8.11 (m, 4 Ho
(PhꢀC(5), ꢀC(10), ꢀC(15), and ꢀC(20)); 8.32 (d, J ¼ 4.6, HꢀC(7), HꢀC(18)); 8.45 (s, HꢀC(12),
HꢀC(13)); 8.59 (d, J ¼ 4.6, HꢀC(8), HꢀC(17)). 13C-NMR (75.47 MHz, CDCl3): 14.5 (MeCH2); 22.0
(C(21)); 39.3 (C(2), C(3)); 61.1 (MeCH2); 113.4, 124.9, 126.6, 127.37, 127.40, 127.5, 127.6 (Cm (Ph), Cp
(Ph)); 128.0 (C(7), C(18)); 129.6 (C(12), C(13)); 132.6 (Co (PhꢀC(5) and ꢀC(20)); 133.5 (C(8), C(17));
133.56 (Co (PhꢀC(10) and ꢀC(15)); 133.58 (Co (PhꢀC(5), ꢀC(10), ꢀC(15), and ꢀC(20)); 142.6, 146.8,
148.2, 153.7, 157.0 (C(a)); 173.7 (C¼O). HR-ESI-MS: 762.1962 (Mþ, C48H34N4O2Znþ; calc. 762.1974).
[(2r,21c,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetraphenyl-2,3-dihydrocyclopropa[b]porphyrinato]zinc-
(II)1) (¼ [Ethyl (1a,1ab,19ab)-1a,19a-Dihydro-3,8,13,18-tetraphenyl-1H,20H,22H-cyclopropa[b]por-
phine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 3a). UV/VIS (CHCl3): 423 (5.32), 524 (3.67), 567
1
(3.67), 594 (3.87), 617 (4.31). H-NMR (500.13 MHz, CDCl3): 0.88 (t, J ¼ 7.1, MeCH2); 2.62 (t, J ¼ 8.2,
HꢀC(21)); 3.52 (q, J ¼ 7.1, MeCH2); 4.47 (d, J ¼ 8.2, HꢀC(2), HꢀC(3)); 7.63 – 7.67 (m, 12 H, Hm (Ph),
Hp (Ph)); 7.90 – 7.93 (m, 2 Ho (PhꢀC(5) and ꢀC(20)); 7.94 – 7.97 (m, 2 Ho (PhꢀC(5) and ꢀC(20)); 8.06 –
8.12 (m, 4 Ho (PhꢀC(10) and ꢀC(15)); 8.27 (d, J ¼ 4.6, HꢀC(7), HꢀC(18)); 8.44 (s, HꢀC(12),
HꢀC(13)); 8.55 (d, J ¼ 4.6, HꢀC(8), HꢀC(17)). HR-ESI-MS: 762.1968 (Mþ, C48H34N4O2Znþ; calc.
762.1974).
{2-[(Ethoxycarbonyl)methyl]-5,10,15,20-tetraphenylporphyrinato}zinc(II) (¼ [Ethyl 5,10,15,20-Tet-
raphenyl-21H,23H-porphine-2-acetato(2ꢀ)-kN21,kN22,kN23,kN24]zinc; 4a). UV/VIS (CHCl3): 419 (6.16),
511 (3.84), 548 (4.70), 583 (3.72). 1H-NMR (300.13 MHz, CDCl3): 1.25 (t, J ¼ 7.1, MeCH2); 3.97 (s,
2 HꢀC(21)); 4.12 (q, J ¼ 7.1, MeCH2); 7.67 – 7.78 (m, 12 H, Hm (Ph), Hp (Ph)); 8.05 – 8.08 (m, 2 Ho
(PhꢀC(20)); 8.19 – 8.23 (m, 6 Ho (PhꢀC(5), ꢀC(10), and ꢀC(15)); 8.69 (d, J ¼ 4.7, 1 HꢀC(b)); 8.79 (s,
1 HꢀC(3)); 8.87 (d, J ¼ 4.7, 1 HꢀC(b)); 8.90 – 8.95 (m, 4 HꢀC(b)). 13C-NMR (75.47 MHz, CDCl3): 14.2
(MeCH2); 29.7 (C(21)); 60.6 (MeCH2); 121.1, 121.5, 126.5 (Cm (Ph), Cp (Ph)); 126.46, 126.53, 126.9 (Cm
(Ph), Cp (Ph)); 128.1, 131.5, 131.9, 132.0, 132.5 (C(b)); 133.2 (Co (PhꢀC(20)); 134.37, 134.40 (Co
(PhꢀC(5), ꢀC(10), and ꢀC(15)); 135.2 (C(3)); 138.0, 142.6, 142.7, 142.9, 148.2, 150.1, 150.2, 150.4, 151.0
(C(a); 172.3 (C¼O). HR-ESI-MS: 762.1968 (Mþ, C48H34N4O2Znþ; calc. 762.1974).
{5-[5-(Ethoxycarbonyl)cyclohepta-1,3,6-trien-1-yl]-10,15,20-triphenylporphyrinato}zinc(II) (¼ [Eth-
yl 4-(10,15,20-triphenyl-21H,23H-porphin-5-yl-kN21,kN22,kN23,kN24)cyclohepta-2,4,6-triene-1-carboxyla-
to(2ꢀ)]zinc; 5a). UV/VIS (CHCl3): 420 (5.88), 483 (3.33), 510 (4.43), 547 (3.63), 584 (3.59).
1H-NMR (500.13 MHz, CDCl3; see Fig. 2 for atom labels): 1.34 (t, J ¼ 7.1, MeCH2); 4.42 (q, J ¼ 7.1,
MeCH2); 3.37 (t, J ¼ 6.0, Hd); 5.53 (ddd, J ¼ 9.1, 6.0, 1.5, He); 5.69 (ddd, J ¼ 9.1, 6.0, 1.3, Hc); 6.77 (dd, J ¼
9.1, 6.0, Hb); 7.25 – 7.50 (m, Hf); 7.51 (d, J ¼ 6.0, Ha); 7.72 – 7.77 (m, 9 H, Hm (Ph), Hp (Ph)); 8.20 – 8.22 (m,
6 Ho (Ph)); 8.88 – 9.01 (m, 6 HꢀC(b)); 9.16 (d, J ¼ 4.6, 1 HꢀC(b)); 9.39 (d, J ¼ 4.6, 1 HꢀC(b)). HR-ESI-
MS: 762.1968 (Mþ, C48H34N4O2Znþ; calc. 762.1974).
[21,121-Bis(ethoxycarbonyl)-5,10,15,20-tetraphenyl-2,3,12,13-tetrahydrodicyclopropa[b,l]porphyrina-
to]zinc(II) (¼ [Diethyl 1a,9a,10a,18a-Tetrahydro-3,8,12,17-tetraphenyl-1H,10H,19H,21H-dicyclopro-
pa[b,l]porphine-1,10-dicarboxylato(2ꢀ)-kN19,kN20,kN21,kN22]zinc; 6a). UV/VIS (CHCl3): 419 (100),
565 (9.0), 607 (13.7), 722 (20.1). HR-ESI-MS: 849.2414 ([M þ H]þ, C52H41N4O2Znþ; calc. 849.2419).
[(2r,21t,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetrakis(3-methoxyphenyl)-2,3-dihydrocyclopropa[b]-
porphyrinato]zinc(II)1) (¼ [Ethyl (1a,1aa,19aa)-1a,19a-Dihydro-3,8,13,18-tetrakis(3-methoxyphenyl)-
1H,20H,22H-cyclopropa[b]porphine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 2b). UV/VIS
(CHCl3): 421 (5.46), 518 (3.85), 541 (3.75), 585 (3.93), 618 (4.48). 1H-NMR (500.13 MHz, CDCl3):
1.24 – 1.30 (m, MeCH2, HꢀC(21)); 3.91 (s, 3 MeO); 3.93 (s, 1 MeO); 4.15 – 4.26 (m, MeCH2); 4.44 (d, J ¼
2.6, HꢀC(2), HꢀC(3)); 7.15 – 7.23 (m, 4 Hp (Ar)); 7.38 – 7.71 (m, 12 H, Ho (Ar), Hm (Ar); 8.35 – 8.37 (m,

Helvetica Chimica Acta – Vol. 91 (2008)
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HꢀC(7), HꢀC(18)); 8.49 (s, HꢀC(12), HꢀC(13)); 8.63 (d, J ¼ 4.6, HꢀC(8), HꢀC(17)). HR-ESI-MS:
882.2390 (Mþ, C52H42N4O6Znþ; calc. 882.2396).
[(2r,21c,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetrakis(3-methoxyphenyl)-2,3-dihydrocyclopropa[b]-
porphyrinato]zinc(II)1) (¼ [Ethyl (1a,1ab,19ab)-1a,19a-Dihydro-3,8,13,18-tetrakis(3-methoxyphenyl)-
1H,20H,22H-cyclopropa[b]porphine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 3b). UV/VIS
(CHCl3): 423 (5.51), 521 (3.87), 567 (3.83), 593 (4.01), 617 (4.47). 1H-NMR (500.13 MHz, CDCl3):
0.84 – 0.94 (m, MeCH2); 2.64 (t, J ¼ 8.2, HꢀC(21)); 3.90 (s, 4 MeO), 4.19 (q, J ¼ 6.1, MeCH2); 4.52 (d, J ¼
8.2, HꢀC(2), HꢀC(3)); 7.46 – 7.61 (m, 8 H, Hm (Ar), Hp (Ar)); 7.65 – 7.73 (m, 8 Ho (Ar)); 8.32 (d, J ¼ 4.6,
HꢀC(7), HꢀC(18)); 8.49 (s, HꢀC(12), HꢀC(13)); 8.60 (d, J ¼ 4.6, HꢀC(8), HꢀC(17)). HR-ESI-MS:
882.2390 (Mþ, C52H42N4O6Znþ; calc. 882.2396).
{2-[(Ethoxycarbonyl)methyl]-5,10,15,20-tetrakis(3-methoxyphenyl)porphyrinato]zinc(II) (¼ [Ethyl
5,10,15,20-Tetrakis(3-methoxyphenyl)-21H,23H-porphine-2-acetato(2ꢀ)-kN21,kN22,kN23,kN24]zinc; 4b).
UV/VIS (CHCl3): 420 (5.79), 484 (3.32), 510 (3.47), 547 (4.36), 583 (3.37). 1H-NMR (300.13 MHz,
CDCl3): 1.26 (t, J ¼ 7.1, MeCH2); 3.92 (s, 1 MeO), 3.95 – 3.96 (m, 3 MeO), 4.06 (s, HꢀC(21)); 4.15 (q, J ¼
7.1, MeCH2); 4.17 (q, J ¼ 7.13, MeCH2); 7.29 – 7.35 (m, 4 H, Hp (Ar)); 7.58 – 7.83 (m, 12 H, Ho (Ar), Hm
(Ar)); 8.77 (d, J ¼ 4.6, 1 HꢀC(b)); 8.86 (s, HꢀC(3)); 8.92 (d, J ¼ 4.6, 1 HꢀC(b)); 8.95 – 8.99 (m,
4 HꢀC(b)). HR-ESI-MS: 882.2390 (Mþ, C52H42N4O6Znþ; calc. 882.2396).
{5-[5-(Ethoxycarbonyl)-3-methoxycyclohepta-1,3,6-trien-1-yl]-10,15,20-tris(3-methoxyphenyl)por-
phyrinato}zinc(II) (¼{Ethyl 3-Methoxy-5-[10,15,20-tris(3-methoxyphenyl)-21H,23H-porphin-5-yl-
kN21,kN22,kN23,kN24]cyclohepta-2,4,6-triene-1-carboxylato(2ꢀ)}zinc; 5b). UV/VIS (CHCl3): 421 (5.69),
484 (3.29), 510 (4.48), 548 (4.32), 584 (3.45). 1H-NMR (500.13 MHz, CDCl3; see Fig. 2 for atom labels):
1.42 (t, J ¼ 7.1, MeCH2); 3.88 (s, 1 MeO); 4.13 (d, J ¼ 7.5, Hb); 4.46 (q, J ¼ 7.1, MeCH2); 6.04 (dd, J ¼ 9.7,
7.5, Hc); 6.56 (s, Ha); 6.78 (dd, J ¼ 9.7, 5.5, Hd); 7.19 (d, J ¼ 5.5, He); 7.63 (s, 3 Hp (Ar)); 7.76 – 7.81 (m, 9 H,
Ho (Ar), Hm (Ar)); 8.91 – 9.01 (m, 6 HꢀC(b)); 9.28 (d, J ¼ 4.6, 1 HꢀC(b)); 9.43 (d, J ¼ 4.6, 1 HꢀC(b)).
HR-ESI-MS: 882.2390 (Mþ, C52H42N4O6Znþ; calc. 882.2396).
[21,121-Bis(ethoxycarbonyl)-5,10,15,20-tetrakis(3-methoxyphenyl)-2,3,12,13-tetrahydrodicyclopro-
pa[b,l]porphyrinato]zinc(II) (¼{Diethyl 1a,9a,10a,18a-Tetrahydro-3,8,12,17-tetrakis(3-methoxyphenyl)-
1H,10H,19H,21H-dicyclopropa[b,l]porphine-1,10-dicarboxylato(2ꢀ)-kN19,kN20,kN21,kN22]zinc; 6b).
UV/VIS (CHCl3): 425 (100) 562 (7.4), 605 (10.9), 718 (12.9). HR-ESI-MS: 969.2836 ([M þ H]þ,
C56H49N4O8Znþ; calc. 969.2764).
[(2r,21t,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetrakis(pentafluorophenyl)-2,3-dihydrocyclopropa[b]-
porphyrinato]zinc(II)1) (¼ [Ethyl (1a,1aa,19aa)-1a,19a-Dihydro-3,8,13,18-tetrakis(2,3,4,5,6-pentafluoro-
phenyl)-1H,20H,22H-cyclopropa[b]porphine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 2c). UV/
VIS (CHCl3): 415 (5.57), 453 (3.06), 516 (3.90), 575 (3.89), 621 (4.88). 1H-NMR (500.13 MHz, CDCl3):
1.33 (t, J ¼ 7.1, MeCH2); 1.47 (t, J ¼ 2.7, HꢀC(21)); 4.31 (q, J ¼ 7.1, MeCH2); 4.37 (d, J ¼ 2.7, HꢀC(2),
HꢀC(3)); 8.32 (d, J ¼ 4.6, HꢀC(7), HꢀC(18)); 8.49 (s, HꢀC(12), HꢀC(13)); 8.61 (d, J ¼ 4.6, HꢀC(8),
HꢀC(17)). 19F-NMR (282.38 MHz, CDCl3): ꢀ 160.79 to ꢀ 160.88 (m, 4 Fo); ꢀ 160.99 to ꢀ 161.07 (m,
2 Fo); ꢀ 162.05 to ꢀ 162.17 (m, 2 Fo); ꢀ 175.58 (t, J ¼ 19.8, Fp); ꢀ 175.82 (t, J ¼ 19.8, 2 Fp); ꢀ 184.43 to
ꢀ 185.37 (m, 2 Fm); ꢀ 185.19 to ꢀ 185.37 (m, 6 Fm). HR-ESI-MS: 1123.0162 ([M þ H]þ,
C48H15F20N4O2Znþ; calc. 1123.0167).
[(2r,21c,3c)-21-(Ethoxycarbonyl)-5,10,15,20-tetrakis(pentafluorophenyl)-2,3-dihydrocyclopropa[b]-
porphyrinato]zinc(II)1) (¼ [Ethyl (1a,1ab,19ab)-1a,19a-Dihydro-3,8,13,18-tetrakis(2,3,4,5,6-pentafluoro-
phenyl)-1H,20H,22H-cyclopropa[b]porphine-1-carboxylato(2ꢀ)-kN20,kN21,kN22,kN23]zinc; 3c). UV/
1
VIS (CHCl3): 410 (100), 513 (2.5), 566 (8.3), 616 (17.0). H-NMR (500.13 MHz, CDCl3): 0.92 (t, J ¼
7.1, MeCH2); 2.52 (t, J ¼ 8.2, HꢀC(21)); 3.69 (q, J ¼ 7.1, MeCH2); 4.02 (d, J ¼ 8.2, HꢀC(2), HꢀC(3));
7.99 (d, J ¼ 4.6, HꢀC(7), HꢀC(18)); 8.28 (s, HꢀC(12), HꢀC(13)); 8.51 (d, J ¼ 4.6, HꢀC(8), HꢀC(17)).
19F-NMR (282.38 MHz, CDCl3): ꢀ 160.46 to ꢀ 161.12 (m, Fo); ꢀ 162.65 to ꢀ 162.98 (m, 2 Fo); ꢀ 175.73
to ꢀ 175.85 (m, 1 Fp); ꢀ 176.20 to ꢀ 176.45 (m, 2 Fp); ꢀ 176.63 to ꢀ 176.90 (m, 1 Fp); ꢀ 184.543 to
ꢀ 185.15 (m, 5 Fm); ꢀ 185.50 to ꢀ 185.98 (m, 3 Fm). HR-ESI-MS: 1123.0160 ([M þ H]þ,
C48H15F20N4O2Znþ; calc. 1123.0167).
{2-[(Ethoxycarbonyl)methyl]-5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato}zinc(II) ( ¼ [Eth-
yl 5,10,15,20-Tetrakis(2,3,4,5,6-pentafluorophenyl)-21H,23H-porphine-2-acetato(2ꢀ)-kN21,kN22,kN23,
kN24]zinc; 4c). UV/VIS (CHCl3): 415 (5.73), 545 (4.39), 579 (3.87), 623 (3.14). 1H-NMR

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(300.13 MHz, CDCl3): 1.22 (t, J ¼ 7.1, MeCH2); 4.16 (q, J ¼ 7.1, MeCH2); 4.30 (s, 2 HꢀC(21)); 8.77 (d, J ¼
4.6, 1 HꢀC(b)); 8.89 (s, HꢀC(3)); 8.92 (d, J ¼ 4.6, 1 HꢀC(b)); 8.95 – 8.99 (m, 4 HꢀC(b)). 19F-NMR
(282.38 MHz, CDCl3): ꢀ 159.32 to ꢀ 159.43 (m, 2 Fo (ArꢀC(5) or ꢀC(20)); ꢀ 160.08 to ꢀ 160.11 (m,
2 Fo (ArꢀC(5) or ꢀC(20)); ꢀ 160.27 to ꢀ 160.42 (m, 4 Fo (ArꢀC(10) and ꢀC(15)); ꢀ 174.80 (t, J ¼ 19.7,
1 Fp (ArꢀC(20)); ꢀ 175.39 to ꢀ 175.64 (m, 3 Fp (ArꢀC(5), ꢀC(10), and ꢀC(15)); ꢀ 184.54 to ꢀ 184.74
(m, 2 Fm (ArꢀC(20)); ꢀ 185.19 to ꢀ 185.34 (m, 6 Fm (ArꢀC(5), ꢀC(10), and ꢀC(15)). HR-ESI-MS:
1123.0162 ([M þ H]þ, C48H15F20N4O2Znþ; calc. 1123.0167).
[21,121-Bis(ethoxycarbonyl)-5,10,15,20-tetrakis(pentafluorophenyl)-2,3,12,13-tetrahydrodicyclopro-
pa[b,l]porphyrinato]zinc(II) (¼{Diethyl 1a,9a,10a,18a-Tetrahydro-3,8,12,17-tetrakis(2,3,4,5,6-penta-
fluorophenyl)-1H,10H,19H,21H-dicylopropa[b,l]porphine-1,10-dicarboxylato(2 ꢀ)-kN19,kN20,kN21,
kN22]zinc; 6c). UV/VIS (CHCl3): 368 (57.9), 410 (100), 554 (10.4), 606 (3.4), 729 (59.2). HR-ESI-MS:
1209.0529 ([M þ H]þ, C52H21F20N4O4Znþ; calc. 1209.0535).
[21,71-Bis(ethoxycarbonyl)-5,10,15,20-tetrakis(pentafluorophenyl)-2,3,7,8-tetrahydrodicyclopropa-
[b,g]porphyrinato]zinc(II) (¼{Diethyl 1a,4a,5a,18a-Tetrahydro-3,7,12,17-tetrakis(2,3,4,5,6-pentafluoro-
phenyl)-1H,5H,19H,21H-dicyclopropa[b,g]porphine-1,5-dicarboxylato(2ꢀ)-kN19,kN20,kN21,kN22}zinc;
7c). Compound 7c is a 2 :1 diastereoisomeric mixture of isobacteriochlorins 7c1 and 7c2, resp. (see
Fig. 1). UV/VIS (CHCl3): 410 (5.25), 490 (3.55), 565 (4.30), 605 (4.80). 1H-NMR (500.13 MHz, CDCl3;
see Fig. 1): 1.29 (t, J ¼ 7.2, MeCH2 (7c1); 1.30 (t, J ¼ 7.0, MeCH2 (7c2); 1.32 – 1.40 (m, HꢀC(21) and
HꢀC(71) (7c2)); 1.44 (d, J ¼ 2.6, HꢀC(21) and HꢀC(71) (7c1)); 3.87, 3.95 (2d, J ¼ 2.9, HꢀC(2) and
HꢀC(8) or HꢀC(3) and HꢀC(7) (7c2)); 3.89 (d, J ¼ 2.6, HꢀC(2), HꢀC(3), HꢀC(7), and HꢀC(8)
(7c1)); 3.86, 3.94 (2d, J ¼ 2.6, HꢀC(3) and HꢀC(7) or HꢀC(2) and HꢀC(8) (7c2)); 4.22 – 4.28 (m,
4 MeCH2 (7c1/7c2)); 7.60, 7.97 (2d, J ¼ 4.3, 4 HꢀC(b) (7c2)); 7.62, 7.99 (2d, J ¼ 4.4, 4 HꢀC(b) (7c1)).
13C-NMR (75.47 MHz, CDCl3): 14.1 (Me); 29.4, 29.7, 30.7, 35.6, 36.7, 37.1, 61.76, 61.82, 65.3, 106.7, 115.7,
123.5, 130.1, 139.0, 143.0, 151.2, 154.8, 166.7, 172.5, 172.6; 216.8 (C¼O). 19F-NMR (282.38 MHz, CDCl3):
ꢀ 161.01 to ꢀ 161.12 (m, 3 F, Fo); ꢀ 161.24 to ꢀ 161.53 (m, 2 F, Fo); ꢀ 161.49 to ꢀ 161.62 (m, 3 F, Fo);
ꢀ 162.44 to ꢀ 162.64 (m, 4 F, Fo); ꢀ 163.00 to ꢀ 163.11 (m, 2 F, Fo); ꢀ 174.98 (t, J ¼ 19.8, 2 F, Fp);
ꢀ 176.03 (t, J ¼ 22.5, 4 F, Fp); ꢀ 176.38 (t, J ¼ 19.8, 2 F, Fp); ꢀ 182.85 to ꢀ 183.04 (m, 2 F, Fm (AꢀC(5));
ꢀ 184.45 to ꢀ 184.82 (m, 6 F, Fm); ꢀ 185.09 to ꢀ 185.39 (m, 10 F, Fm). HR-ESI-MS: 1209.0529 ([M þ
H]þ, C52H21F20N4O4Znþ; calc. 1209.0457).
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sensitizers in Photodynamic Therapyꢃ, in ꢄThe Porphyrin Handbookꢃ, Eds. K. M. Smith and R.
Guilard, Academic Press, San Diego, 2000, Vol. 6; J. G. Moser in ꢄPhotodynamic Tumour Therapy –
2nd and 3rd Generation Photosensitizersꢃ, Harwood Academic Publishers, Amsterdam, 1998; R.
Bonnett, Chem. Soc. Rev. 1995, 24, 19; E. D. Sternberg, D. Dolphin, C. Brꢂckner, Tetrahedron 1998,
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Received May 16, 2008