Synthesis of long-wavelength absorbing porphyrin m-benzoic acids as molecular tectons for surface studies

Article abstract of DOI:10.3987/COM-17-13744

Porphyrins are becoming increasingly important building blocks in material science. This is due in part to several favorable characteristics; such as strong absorption into the infrared region, tunable electronic properties and the possibility to modify and define the porphyrin core in multiple ways. Herein we report synthetic methodologies for porphyrin-based molecular tectons for surface studies. The study aims to generate porphyrins with directional anchoring groups of different length and we report a library of long-wavelength absorbing porphyrins with a special focus on organometallic coupling reactions for the introduction of benzoic acid moieties as anchor groups.

Full text of DOI:10.3987/COM-17-13744

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HETEROCYCLES, Vol. 94, No. 8, 2017
HETEROCYCLES, Vol. 94, No. 8, 2017, pp. 1518 - 1541. © 2017 The Japan Institute of Heterocyclic Chemistry
Received, 15th May, 2017, Accepted, 19th June, 2017, Published online, 30th June, 2017
DOI: 10.3987/COM-17-13744
SYNTHESIS OF LONG-WAVELENGTH ABSORBING PORPHYRIN
m-BENZOIC ACIDS AS MOLECULAR TECTONS FOR SURFACE
STUDIES
Alina Meindl, Aoife A. Ryan, Keith J. Flanagan, and Mathias O. Senge*
School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences
Institute, 152-160 Pearse Street, Trinity College Dublin, The University of Dublin,
Dublin 2, Ireland. E-mail: sengem@tcd.ie.
Abstract – Porphyrins are becoming increasingly important building blocks in
material science. This is due in part to several favorable characteristics; such as
strong absorption into the infrared region, tunable electronic properties and the
possibility to modify and define the porphyrin core in multiple ways. Herein we
report synthetic methodologies for porphyrin-based molecular tectons for surface
studies. The study aims to generate porphyrins with directional anchoring groups
of different length and we report a library of long-wavelength absorbing
porphyrins with a special focus on organometallic coupling reactions for the
introduction of benzoic acid moieties as anchor groups.
INTRODUCTION
Functionalized nanomaterials with defined shapes and sizes are gaining more and more popularity for
applications such as electronics, light-energy conversion and photonics. Porphyrins represent very
promising materials for such applications due to their strong absorption bands in the visible region,
tunable electronic properties and scope of possible modifications. Materials exhibiting strong absorption
in the infrared region are especially of interest. Even though there are many porphyrin-based
nanomaterials current studies target composite 2D and 3D materials. One example is the use of suitably
functionalized porphyrins as molecular tectons in SMOFs, MOFs, DSSCs and for binding to surfaces.1
Such applications require porphyrin building blocks where: (1) tailored functionalization of the porphyrin
core can be used to optimize key performance for different applications and (2) suitable functional groups
can direct their spatial arrangement in a given environment or facilitate the assembly to nano-networks of
these compounds. Molecular porphyrin tectons can be described as building blocks on a molecular
level.1g These building blocks interact with reciprocal counterparts in a specific manner to form

HETEROCYCLES, Vol. 94, No. 8, 2017
1519
molecule-substrate or -surface interactions. Interactions are based on different means such as ionic
self-assembly, re-precipitation or coordination polymerization. Notably, the use of weak binding forces
offers a facile approach, e.g., to 3D supramolecular networks stabilized by hydrogen bonding or
electrostatic forces. Very dense packing can be achieved by porphyrins with unreactive meso-substituents
(e.g., phenyl-groups) or porphyrin itself due to Van der Waals interactions. Introducing functional groups
to the porphyrin such as pyridyl, alkoxy or carboxyphenyl helps to fine-tune the strength, selectivity and
direction of these intermolecular interactions. Thus, porphyrins provide valuable tools to form molecular
constructs such as porous networks, aggregates or closed-packed arrays.2
H-Bonds are a suitable ‘construction principle’ which can be tuned by varying the number of H-bonds in
the material and the strategic placement of hydrogen bonding groups on a porphyrin can be used to design
3
specific nanoarchitectures based on the orientation of the H-bonds. A classic example for porphyrins is
the formation of right angular structures when H-bonding groups are attached at the meso-5,10-positions
3
,4
opposed to a linear arrangement derived from H-bonding groups in the meso-5,15-positions. Similarly,
ortho- and para-carboxyphenyl groups have been shown to impact the nanomaterial structure, for
example via different orientations in the interspace of layered double hydroxide.5 Notably,
carboxyphenylporphyrins were key components of some of the earliest mesoporous porphyrin-based
6
MOFs and have been widely used in surface chemistry as chemosensors, coordination polymers and
7
8
catalysts. Other applications of carboxylic acid porphyrins include use in photodynamic therapy or
DSSCs,1a,9 and they present a suitable means to create molecular tectons.
Figure 1. Illustration of porphyrin carboxylic acids as directional molecular tectons
In the context of exploratory studies on the use of surface-bound porphyrins as biosensors we were
interested in providing porphyrins with unique optical properties capable of binding to surface materials
in a directional manner. One possible avenue would be the attachment of porphyrins via π-π-interactions
to a graphene surface and then using COOH groups for the attachment of bioconjugates. This requires the
COOH anchors to point towards one side of the system away from the porphyrin plane, similar to the
orientation utilized by Collman in his picket-fence porphyrins as models for oxygen binding heme
proteins.10 A simple means to achieved different directionalities and spacings is provided by using

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HETEROCYCLES, Vol. 94, No. 8, 2017
meso-benzoic acid residues as directional anchor groups (Figure 1).Various syntheses have been reported
to generate porphyrins with different aryl-carboxylic acid groups in the past and range from
Sonogashira1a,9b,11 and Suzuki couplings to nucleophilic substitution reactions. Herein we give a brief
account of synthetic studies aimed to synthesize porphyrins with directional anchoring groups of different
length. We were especially interested in testing organometallic coupling reactions for the introduction of
Ar-COOH and the generation of long-wavelength absorbing meso-β-β-triply–linked surface binding
molecular tectons.
12
13a
RESULTS AND DISCUSSION
SYNTHESIS OF AN A -TYPE TETRACARBOXYLIC ACID PORPHYRIN
4
Our first target compound was the tetrasubstituted m-benzoic acid porphyrin which was deemed to be a
good starting point for our synthetic studies due to its ease of synthesis. Furthermore, it provides a very
useful reference for comparison with other more complex carboxylic acid porphyrins. Therefore, our
investigations began with the synthesis of tetrasubstituted porphyrin 1 using standard condensation
procedures.13b Further modification included the insertion of nickel into the porphyrin core via reaction
with Ni(acac) to give 2 with a yield of 94%. Next, the acid was generated by deprotection of the
2
carboxylic ester under standard base hydrolysis conditions. The reaction required a large excess of base
and long reaction times until the starting material was completely consumed. After acidification and
extraction the free carboxylic acid 3 was obtained in a yield of 81% after recrystallization (Scheme 1).
Scheme 1. Synthesis of simple, A
pyrrole, CH Cl , BF ·OEt , rt, 16 h, (ii) DDQ, rt, 1 h; b) Ni(II)(acac)
KOH (400 equiv.) in H O, THF/MeOH (1:1), 66 °C, 72 h.
4
-type m-benzoic acid porphyrins. a) (i) 3-carbomethoxybenzaldehyde,
2
2
3
2
2
(2.5 equiv.), toluene, 120 °C, 18 h; c)
2

HETEROCYCLES, Vol. 94, No. 8, 2017
1521
Scheme 2. Synthesis of a triply-fused bisporphyrin with two m-benzoic acid residues. a) Pd(PPh
3
)
4
(20
mol%), K
3
PO
2
4
(10 equiv.), THF, 66 °C, 18 h; b) (i) Zn(OAc)
(2.5 equiv.), toluene, 120 °C, 3 h; c) DDQ (5 equiv.), Sc(OTf)
8 h; d) KOH (excess) in H O, THF/MeOH (1:1), 70 °C, 3 h; e) NBS (1 equiv.), CHCl
(PPh (10 mol%) THF/TEA (3:1, v/v), 66 °C, 18 h; g) TBAF, THF; h) AsPh
(15 mol%), THF/TEA (3:1, v/v), 66 °C 18 h.
2
(5 equiv.), MeOH, CHCl
(5 equiv.), toluene, 50 °C,
, pyridine, rt, 2 h;
3
, 70 °C, 1 h; or
(
ii) Ni(acac)
3
1
2
3
f) CuI (20 mol%), PdCl
1.1 equiv.), Pd (dba)
2
3
)
2
3
(
2
3
Synthesis of S-extended biscarboxylic acid porphyrins
While A -type systems are easily accessible, they are not that interesting, nor unique. In light of current
4
reports on the use of π–conjugated and triply-fused systems and related materials for the solubilization of
and aggregation with carbon nanotubes14 we aimed to access related species capable of further
bioconjugation and for the use as molecular tectons as illustrated in Figure 1. Triply-fused dimers offer a
range of very interesting and promising properties, notably as optical nonlinear materials due to
comprehensive π-electron delocalization throughout the molecules.15 Furthermore, they exhibit large

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HETEROCYCLES, Vol. 94, No. 8, 2017
absorptivities for visible light and a significant red-shift of the absorption spectra into the IR region.16
Their prominent electron transport properties make them possible candidates for organic semiconductors
1
7
or photovoltaic materials. For these reasons,
we decided to synthesize two related
biscarboxylic acid porphyrin dimers, the
directly fused compound 7b and, for
comparison, the ethyne-bridged dimer 6f
(Scheme 2).
For the synthesis of the triply-fused dimer
starting material 4a was subjected to Suzuki
conditions with a boronate ester either
containing an ethyl group at the ester to yield
porphyrin 5a in 74% or with a methyl group
to yield 5c in 90%. Metal coordination of 5a
with zinc resulted in compound 6a in 85%.
The metal insertion was performed prior to
the next step as the central metal ion plays an
important part in oxidative fusing and
zinc(II) is typically the metal ion of choice in
such reactions.16b Subsequent oxidative
Figure 2. View of the molecular structure of 6a in the
crystal. Hydrogen atoms have been removed for clarity;
thermal ellipsoids give 50% probability. Selected bond
angles [°] and lengths [Å]: Zn-N21 2.034(9), Zn-N22
2.015(8), Zn-N23 2.037(1), Zn-N24 2.0276(9), C4-C5
1.405(8), C5-C6 1.390(7), C9-C1) 1.395(5), C10-C11
1.399(5), C14-C15 1.384(7), C15-C16 1.388(7),
C19-C20 1.382(5), C20-C1 1.400(5), C4-C5-C6
1
1
25.5(3), C9-C10-C11 125.0(3), C14-C15-C16
27.1(3), C19-C20-C1 126.2(3).
fusing using DDQ/Sc(OTf) generated the bisporphyrin product 7a from 6a in a yield of 71%. To obtain
3
target compound 7b porphyrin 7a was deprotected via hydrolysis using NaOH. Compounds such as 5c/d
can also be used as starting materials for Pd-catalyzed cross-coupling reactions to yield bisporphyrin
carboxylic acids with different linker units. This is exemplified by sequence 5d to 6f (Scheme 2) which
gives the target 6f in an overall yield of 29%. Such compounds are of interest in photonics as two-photon
absorbers and subsequent studies on this will be reported elsewhere. To obtain the porphyrin monomer
with two carboxylic ester groups the dibromoporphyrin 4b was subjected to Suzuki cross-coupling
conditions. This reaction gave compound 5b in 78% yield.
For compound 6a single crystals suitable for X-ray crystallographic analysis were obtained. The structure
shows a classic A B Zn(II)-porphyrin structure bearing aryl substituents, in which the porphyrin ring is
2
almost planar and the aryl substitutent are held in a nearly orthogonal position (Figure 2). The angles
between the aryl ring and 24-atom mean plane of the porphyrin macrocycle are 78.8(4)° (C10), 81.3(4)°
(C20) and 118.6(3)° (C15), respectively. Compared to literature examples of tetracoordinated Zn(II)
A
2
B-porphyrins [angles of 56.1–85.2° for the C10 and C20 positions (A ), and 101.3–121.0° for the C5
2

HETEROCYCLES, Vol. 94, No. 8, 2017
1523
1
8
position], these values fall within the expected range for such tetracoordinated complexes. This is also
reflected in the structure of the A -porphyrin [5,10,15-tris(4-methoxyphenyl)porphyrinato]zinc(II), which
3
shows similar angles of 83.5° for the 5,15-A groups and an angle of 117.0° for the A group opposite the
free meso-position.19 Considering the angles around the meso-positions, C4-C5-C6 [125.5(3)°],
C9-C10-C11 [125.0(3)°], C14-C15-C16 [127.1(3)°], and C19-C20-C1 [126.2(3)°], there is an obvious
effect of the substitution of the pattern, namely, a flattening of the angle around the free meso-position
and contraction of the substitution around the B-group. This is within the range expected for related
literary compounds of 126.2–127.7°.18a-c In the packing arrangement of compound 6a, a head-to-head
interaction is noted with the free meso-positions lining up to face one another. However, there are no
notable close contacts between the molecules.
Extending the ‘arm length’ of peripheral residues
Moving forward in our approach we decided to extend the length of the peripheral anchor groups.
Biosensors utilizing 11-mercaptoundecanonic acid as binding sites for various receptors have been
previously reported in the literature.20 These long chains provide suitable anchor groups for specific
2
0
bioconjugation and have shown to give good results for different biosensors. Therefore we decided to
attempt building porphyrins with longer side
arms to mimic the properties of
11-mercaptoundecanonic acid based sensors
(Scheme 3). Besides that, supramolecular
porphyrin tectons with longer acid chains
could be useful for porphyrin hybrid
nanoarchitectures and could result in a larger
interspace between
a
layered double
hydroxide. This would provide an additional
means to sculpt and design nanomaterials.
In practical terms we decided to apply an
approach for the functionalization of
5,10,15,20-tetrakis(3-hydroxyphenyl)por-
2
1
phyrin, recently developed by us. Initially,
we decided to use a monosubstituted
derivative for test reactions to explore the
feasibility of this approach for longer chains.
Suzuki coupling methodologies were applied
Scheme 3. Synthesis of monofunctionalized porphyrins
via arm attachment. a) 3-Hydroxyphenylboronic acid
Pd(PPh
h; b) (i) K
or 1,6-diiodohexane (11), rt, 18 h; c) potassium
thioacetate (excess), DMF, rt, 18 h; d) Zn(OAc) (5
equiv.), MeOH, CHCl , 70 °C, 1 h.
3
)
4
(20 mol%), K
3
PO
4
(10 equiv.), THF, 66 °C, 18
2
CO , DMF, 0.5 h, (ii) 1,6-dibromohexane (10)
3
2
3

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HETEROCYCLES, Vol. 94, No. 8, 2017
using 3-hydroxyphenylboronic acid with a bromoporphyrin 8 followed by two consecutive S
N
2 reactions
(Scheme 3). Installation of the phenol group using standard Suzuki coupling conditions proceeded in
excellent yields of up to 84% giving porphyrin 9. The subsequent S 2 reaction of this phenol porphyrin 9
N
with both diiodo- and dibromohexane proceeded in excellent yields of 73% (11) and 69% (10)
respectively. Another S 2 reaction using excess potassium thioacetate yielded the desired thioacetate in
6% yield (12). Subsequent metallation with Zn(II) was also carried out in good yield of 74% to give the
final target compound 13.
Utilizing the same methodology arm extension was achieved for the tetrasubstituted porphyrin 14
Scheme 4). Compound 15 was synthesized using K CO and methyl-5-bromovalerate in DMF and the
desired porphyrin was isolated in 77%. Subsequent metallation utilizing Zn(OAc) gave porphyrin 16 in
9% yield. A slight variation in the reaction sequence of the same methodology was used to obtain target
N
8
(
2
3
2
8
compounds 24 and 25. Here compound 14 was first metallated with Ni(acac) yielding porphyrin 17 in
2
8
0%. For the S
methodology and the protected compounds 20 and 21 were isolated in 76 and 82% yields, respectively.
These porphyrins were then used for the subsequent S 2 reaction to synthesize 22 in 56% and 23 in 62%
yield. Base hydrolysis of the ester groups yielded the desired targets 24 and 25 in good yields of 65 and
1%, respectively. This methodology proved to be a straightforward approach to introduce longer chains
N
2 reaction, the bromocarboxylic acids 18 and 19 were used with standard esterification
N
7
to the meta-aryl-position of the porphyrin. Furthermore, this strategy is compatible with either mono- or
tetrasubstitution.
Scheme 4. Synthesis of A
methyl 5-bromovalerate (12 equiv.), rt, DMF, 24 h; b) Zn(OAc)
Ni(acac) (2.5 equiv.), toluene/DMF (10:1, v/v), 120 °C, 24 h; d) acetyl chloride, MeOH, 70 °C , 24 h; e)
CO (12 equiv.), bromoester 20 or 21 (12 equiv.), rt, DMF, 24 h; f) KOH (excess) in H O, THF/MeOH
1:1, v/v), 66 °C, 24 h.
4
-type porphyrins with extended carboxylic acid residues. a) K
2
CO
3
(12 equiv.),
2
(5 equiv.), MeOH, CHCl
3
, 70 °C, 1 h; c)
2
K
2
3
2
(

HETEROCYCLES, Vol. 94, No. 8, 2017
1525
For compound 13 single crystals
suitable for X-ray crystallographic
analysis were obtained. The
structure contained one molecular
unit associated with two solvent
chloroform molecules (Figure 3).
As with compound 6a, porphyrin
1
3 exhibited an almost planar
macrocycle ring with meso-aryl
substituents orientated orthogonal
to the 24-atom mean plane of the
porphyrin system. The angles
between the aryl ring and the
Figure 3. View of the molecular structure of 13 in the crystal.
Hydrogen atoms and solvent molecules have been removed for
clarity; thermal ellipsoids give 50% probability. Selected bond
angles [°] and lengths [Å]: Zn-N21 2.063(6), Zn-N22 2.042(5),
Zn-N23 2.060(6), Zn-N24 2.056(5), C4-C5 1.401(4), C5-C6
24-atom mean plane were 103.7
1
1
1
.404(4), C9-C10 1.404(5), C10-C11 1.393(3), C14-C15
.391(4), C15-C16 1.413(4), C19-C20 1.392(5), C20-C1
[
C5, 73.2(3)°, C10, 82.9(3)°, C15,
.416(3),
C4-C5-C6
125.2(2),
C9-C10-C11
125.7(2),
and 85.6(3)° C20] with the largest
angle associated with the B group
C14-C15-C16 125.7(2), C19-C20-C1 125.1(2).
of the A
Zn(II) A
3.4° for A groups and 62.6–105.0° for B groups, suggesting that the rotations are quite liberal in such
3
B system. Other reported
B systems,18d show a large range of aryl ring rotation from the 24-atom mean plane at 77.7–
3
8
2
2
compounds. The overall molecular packing features an interesting axial ligand coordination of atom O2
to the Zn(II) metal center of the nearest neighbor forming a penta-coordinated structure (not shown).
Features like this have been previously reported by Gomes et al. in which the axial ligand is being
provided by the meso-substituted B-group.22a Additionally, one hydrogen bond [C64-H64B···N24] with a
donor-acceptor distance of 3.361(9) Å was noted, due of this axial ligand. This feature gives a packing
pattern in the unit cell of head-to-tail orientation and solvent chloroform molecules sandwiched between
the planes of porphyrin rings. The structure contains several hydrogen bonds between solvent chloroform
molecules and the porphyrin structure.
Synthesis of triply-fused biscarboxylic acid porphyrins with extended ‘arms’
Methodologies similar to those outlined in the preceding section were employed for the synthesis of the
‘
fused-dimer’ derivative 31 (Scheme 5). The phenol substituted porphyrin 26 was subjected to
nucleophilic substitution with a bromo ester to form 27 in good yield. Subsequent metallation with
zinc(II) and oxidation with Sc(OTf) gave the fused dimer 29 in a yield of 54%, along with
3

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HETEROCYCLES, Vol. 94, No. 8, 2017
meso-meso-linked porphyrin dimer 30. Deprotection gave the desired free carboxylic acid substituted
porphyrin 31 in 86% yield.
Ar
Ar
Ar
NH
N
N
NH
N
N
N
N
N
N
a)
b)
Zn
HN
HN
OH
O
O
Ar
Ar
Ar
2
6
27 77%
28 96%
O
O
where Ar = (3,5-di-t-butyl)phenyl
c)
OMe
OMe
Ar
Zn
Ar
Ar
Ar
Ar
Zn
Ar
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Zn
Ar
Zn
Ar
+
N
N
O
O
O
O
3
0 45%
O
29 R = Me 54%
O
O
O
OR
OMe
RO
MeO
d)
3
1 R = H 86%
Scheme 5. Synthesis of a triply-fused bisporphyrin with elongated arms for the carboxylic acid residues.
a) K CO (12 equiv.), bromoester (12 equiv.), rt, DMF, 24 h; b) Zn(OAc) (5 equiv.), MeOH, CHCl
(5 equiv.), toluene, 50 °C, 18 h; d) NaOH (excess), THF/MeOH,
2
3
2
3
,
7
8
0 °C, 1 h; c) DDQ (5 equiv.), Sc(OTf)
0 °C, 18 h.
3
UV/vis studies
In addition, we investigated the absorption properties of these molecular porphyrin tectons (Figure 4).
When the monomeric species 28 is compared to the fused dimer 29 a very distinctive red shift can be
observed. As expected the monomer 28 shows the characteristic absorption pattern of a metal porphyrin.
In addition to the significant bathochromic shift of the triply-fused dimer 29 a broad splitting of the Soret
band can be observed too, which is due to excitonic coupling between the two porphyrin units. The
directly-linked dimer 30 is less red shifted than the fused-dimer 29 but more red shifted than the monomer

HETEROCYCLES, Vol. 94, No. 8, 2017
1527
2
8. Again, a split in the Soret band can be observed due to excitonic coupling of the two porphyrin
moieties. Our findings correlate with results that have already been reported before in literature for
similar compounds.16b Similar trends were also observed for compounds 6a and 7a.
Furthermore, we were interested if the two
series of triply-fused porphyrin dimers
show any difference in the absorption
spectra.
Therefore,
we
compared
compound 7a, which has the carboxylic
acid directly on the aromatic ring with
compound 29 where the acid is attached on
an extended ‘arm’ further away from the
porphyrin core. As expected, there was no
significant impact on the absorption Figure 4. UV/vis absorption spectra of monomer 28
(
2
orange), directly-linked dimer 30 (blue), and fused dimer
spectrum.
9 (green) in CH Cl
2
2
.
CONCLUSION
Herein we reported the synthesis of a series of different m-benzoic acid porphyrins for possible
application as (supra)molecular tectons for surface binding studies. Our approach is based on a logical
and straightforward step-wise functionalization of the porphyrin core to achieve the desired substituent
pattern and orientations necessary for surface binding studies. The compounds vary from monomeric
compounds with one to four carboxylic acid moieties to S-extended biscarboxylic acid porphyrin dimers
which prominently feature long-wavelength absorbance. Furthermore, we explored the option to increase
the length of the peripheral acid residues to broaden the possible application of these materials for
specific bioconjugation in biosensors.
EXPERIMENTAL
General experimental conditions and instrumentations were as described before.23 Compounds 1,13b,24
2
5
25
26 27 28
29
30
31
4
a, 4b, 4c, 8, 9, 10, 14, and 17 were prepared according to literature procedures.
[5,10,15,20-Tetrakis(3’-carboxymethyl)phenylporphyrinato]nickel(II) (2). The free base porphyrin 1
(
260 mg, 0.31 mmol) was reacted with nickel(II) acetate (197 mg, 0.77 mmol) in toluene (30 mL) for
1
8 h at 120 °C and the crude product purified via column chromatography on silica gel
CH Cl /MeOH, 9:1, v/v) followed by recrystallization from CH Cl /MeOH. Yield: 260 mg (0.29 mmol,
4%) of red crystals. Mp >300 °C; R : 0.61 (CH Cl /n-hexane/MeOH, 1:1:0.05, v/v/v, silica gel, 6×3 cm);
(
2
2
2
2
9
f
2
2

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HETEROCYCLES, Vol. 94, No. 8, 2017
1H NMR (400 MHz, CDCl
Ar-H), 8.39 (d, J = 7.6 Hz, 4H, Ar-H), 8.67-8.71 (m, 12H, Ar-H, H
Gꢀ(ppm): 167.1, 142.8, 141.0, 137.6, 134.2, 132.3, 129.2, 129.0, 127.1, 118.1, 52.3; UV/vis (CH
3
ꢁ
) Gꢀ(ppm): 3.95 (s, 12H, CH ), 7.76 (t, J = 7.6 Hz, 4H, Ar-H), 8.19 (d, J = 7.6 Hz, 4H,
13
E
); C NMR (100 MHz, CDCl )
3
2
Cl
2
) Omax
+
+
(
(
log H): 414 (5.1), 527 nm (4.14); LRMS (MALDI) m/z (%): 902 (30) [M ], 842 (36) [M – C
2
H
3
O
2
], 783
+
+
+
+
52) [M – C
4
H
6
O
4
], 708 (100) (M – C10
H
10
O
4
), 648 (80) (M – C12
Ni: 902.1887).
5,10,15,20-Tetrakis(3’-carboxy)phenylporphyrinato]nickel(II) (3). Compound 2 (250 mg, 0.28
mmol) in THF/MeOH (100 mL, 1:1, v/v) was heated to 60 °C, followed by reaction with KOH (6.2 g,
11.80 mmol) at 66 °C for 3 days in the absence of light. The reaction was cooled to rt and acidified
to pH 4 using 1M HCl. The organic layer was extracted using CH Cl and dried over Na SO , filtered
and solvent removed in vacuo. The residue was suspended in n-hexane and filtered. Yield: 190 mg
H
13
O
6
), 514 (24) [M – C20
H
20
O );
8
HRMS (EI) m/z: 902.1901 (Calcd. for C52
H
36
N
4 8
O
[
1
2
2
2
4
(
0.22 mmol, 81%) of a red solid. Mp >300 °C; R
f
: 0.25 (CH
2
Cl
2
/n-hexane/MeOH, 1:1:0.1, v/v/v, silica
1
gel, 6×3 cm); H NMR (400 MHz, CDCl
3
/pyridine-d
5
, 30:1) Gꢀꢀ(ppm): 7.73 (t, J = 7.6 Hz, 4H, Ar-H), 8.13 (d, J =
13
7
.6 Hz, 4H, Ar-H), 8.45 (d, J = 7.6 Hz, 4H, Ar-H), 8.77-8.75 (m, 12H, Ar-H, H
E
); C NMR (100 MHz,
) Gꢀꢀ(ppm): 169.3, 143.9, 140.7, 137.4, 134.7, 133.6, 130.7, 129.2, 126.9, 118.6; UV/vis
/MeOH, 99:1) Omax (log H): 411 (5.29), 525 (4.08), 557 nm (3.10); LRMS (MALDI) m/z (%): 846
CDCl
3
(CH
2
Cl
2
+
+
+
+
+
(
16) [M ], 800 (47) [M – CHO
2
], 726 (36) [M – C
7
H
5
O
2
], 680 (100) [M – C
8
H
6
O
4
], 634 (49) [M –
+
C
9
H
7
O
6
], 514 (21) [M – C16
H
12
O
8
]; HRMS (MALDI) m/z: 846.1274 (Calcd. for C48
H
28
N
4 8
O
Ni:
846.1461).
1
0,20-Bis(3,5-di-tert-butyl)phenyl-5-(3’-carboxyethyl)phenylporphyrin (5a). 5-Bromo-10,20-(3,5-di-
PO
(53 mg, 0.05 mmol) and ethyl 3-(4,4,5,5-tetraethyl-
,3,2-dioxaborolan-2-yl)benzoate (252 mg, 0.91 mmol) under argon for 18 h. The solvent was
Cl before being washed with saturated aqueous.
and water. The organic layer was dried over Na SO , filtered and solvent removed in vacuo.
The crude product was purified via column chromatography on silica gel (CH Cl /n-hexane, 1:2, v/v)
tert-butyl)phenylporphyrin 4a (175 mg, 0.23 mmol) was heated to 66 °C in the presence of K
3
4
(
472 mg, 2.23 mmol), Pd(PPh
)
3 4
1
removed in vacuo and the residue dissolved in CH
NaHCO
2
2
3
2
4
2
2
followed by recrystallization from CH
Mp >300 °C; R : 0.53 (CH Cl
2.93 (s, 2H, NH), 1.34 (t, J = 7.2 Hz, 3H, CH
H, Ar-H), 8.09-8.10 (m, 4H, Ar-H), 8.38 (d, J = 7.6 Hz, 1H, Ar-H), 8.46 (d, J = 7.6 Hz, 1H, Ar-H), 8.77 (d, J =
.6 Hz, 2H, H ), 8.87-8.88 (m, 1H, Ar-H), 8.92 (d, J = 4.6 Hz, 2H, H ), 9.06 (d, J = 4.6 Hz, 2H, H ), 9.33 (d, J = 4.6
Hz, 2H, H ), 10.22 (s, 1H, Hmeso); C NMR (100 MHz, CDCl ) Gꢀꢀ(ppm): 166.9, 149.0, 148.9, 143.1, 140.6,
38.1, 134.6, 132.6, 131.7, 131.2, 131.0, 130.1, 130.0, 129.0, 128.9, 126.6, 121.2, 121.1, 118.7, 104.9,
2
Cl
2
/n-hexane. Yield: 140 mg (0.17 mmol, 74%) of red crystals.
1
f
2
2
/n-hexane, 1:1, v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) Gꢀꢀ(ppm):
–
2
3
), 1.54 (s, 36H, HtBu), 4.43 (q, J = 7.2 Hz, 4H, CH
2
), 7.80-7.81 (m,
4
β
β
β
13
β
3
1

HETEROCYCLES, Vol. 94, No. 8, 2017
1529
6
1.2, 35.1, 31.7, 14.3; UV/vis (CH
2
Cl ) Omax (log H): 414 (5.65), 510 (4.20), 545 (3.64), 585 (3.64), 639
2
+
+
+
nm (3.50); LRMS (MALDI) m/z (%): 835 (53) [M ], 806 (100) [M – C
H
2 5
], 791 (78) [M – C
3
H
8
], 775
+
+
(
82) [M – C
34.4873).
0,20-Bis(3,5-di-tert-butyl)phenyl-5,15-bis(3’-carboxyethyl)phenylporphyrin (5b). Reaction of
,15-dibromo-10,20-(3,5-di-tert-butyl)phenylporphyrin 4b (200 mg, 0.24 mmol), K PO (502 mg,
.37 mmol), Pd(PPh (55 mg, 0.05 mmol) and ethyl 3-(4,4,5,5-tetraethyl-1,3,2-dioxaborolan-
3
H
8
O], 734 (32) [M – C
6
H
14O]; HRMS (MALDI) m/z: 834.4846 (Calcd for C57
H
62
N
4
O :
2
8
1
5
2
2
7
3
4
)
3 4
-yl)benzoate (654 mg, 2.37 mmol) following the procedure given for 5a gave 180 mg (0.18 mmol,
1
8%) of purple crystals. Mp >300 °C; R
) Gꢀꢀ(ppm): –2.73 (s, 2H, NH), 1.38 (t, J = 7.2 Hz, 6H, CH
), 7.71-7.77 (m, 4H, Ar-H), 7.86-7.87 (m, 4H, Ar-H), 8.20 (d, J = 7.3 Hz, 2H, Ar-H), 8.38 (d, J =
f
: 0.29 (CH
2
Cl
2
/n-hexane, 1:1, v/v, silica gel, 6×3 cm); H NMR
(
400 MHz, CDCl
3
3
), 1.46 (s, 36H, HtBu), 4.41 (q, J = 7.2
Hz, 4H, CH
2
1
3
7
.3 Hz, 2H, Ar-H), 8.66 (d, J = 4.6 Hz, 4H, H
MHz, CDCl ) G (ppm): 166.8, 148.8, 142.6, 140.9, 138.2, 134.7, 131.5, 129.9, 129.1, 128.9, 128.2, 126.7,
23.4, 121.8, 121.1, 118.6, 61.2, 35.0, 31.7, 14.3; UV/vis (CH Cl ) Omax (log H): 420 (5.62), 517 (4.10),
53 (3.66), 593 (3.48), 647 nm (3.55); LRMS (MALDI) m/z (%): 982 (83) [M ], 954 (100) [M – C
β
), 8.69 (m, 2H, Ar-H), 8.66 (d, J = 4.6 Hz, 4H, H
β
); C NMR (100
3
1
5
8
2
2
+
+
2
5
H ],
+
+
95 (40) [M – C
6
H
14], 853 (17) [M – C
7
H
14
O
2
]; HRMS (MALDI) m/z: 982.5369 (Calcd for
C
60
H
70
N
4 4
O
: 982.5397).
1
0,20-Bis(3,5-di-tert-butyl)phenyl-5-(3’-carboxymethyl)phenylporphyrin (5c). Porphyrin 4a (300 mg,
.39 mmol) was dissolved in THF (20 mL). The solution was then degased via three freeze-pump-thaw
0
cycles and the flask was purged with argon. 3-Methoxycarbonylphenylboronic acid (282 mg, 1.57 mmol),
Pd(PPh (68 mg, 0.06 mmol) and K PO (831 mg, 3.92 mmol) were added. The mixture was stirred at
6 °C for 16 h. The solvent was removed in vacuo and the crude product was washed with NaHCO and
and filtered through silica gel.
:petroleum ether (1:1). The target
3
)
4
3
4
6
3
H
2
O. The solvent was removed and the residue was dissolved in CH
2
Cl
2
The porphyrin was purified with column chromatography using CH
2
Cl
2
was obtained in 90% yield (291 mg, 0.35 mmol) after recrystallization from CH
2
Cl
2
: MeOH. Mp
) Gꢀꢀ(ppm): –
), 7.82 (m, 6H, J = 4.5 Hz, Ar-H),
.85 (s, 1H, Ar-H), 8.21 (d, 4H, J = 1.7Hz, Ar-H), 8.40 (d, 1H, J = 7.5 Hz, Ar-H), 8.48 (d, 1H, J = 7.9Hz, H ), 8.78 (d,
H, J = 4.8 Hz, H ), 8.90 (s, 1H, Ar-H), 8.96 (d, 2H, J = 4.7 Hz, H ), 9.08 (d, 2H, J = 4.6 Hz, H ), 9.35 (d, 2H, J = 4.6
Hz, H ), 10.24 (s, 1H, Hmeso); C NMR (150 MHz, CDCl ): Gꢀꢀ(ppm): 148.8, 143.0, 142.5, 140.5, 138.1,
34.5, 132.2, 131.5, 131.0, 129.9, 128.8, 128.5, 126.5, 126.0, 121.0, 120.9, 118.4, 105.0, 104.7, 99.8, 52.2,
4.9, 31.9, 31.6, 29.5; UV/vis (CH Cl ): λmax (log ε) = 415 (5.69), 511 (4.28), 545 (3.85), 584 (3.77), 639
]: 820.4716).
1
>
300 °C; R
f
: 0.39 (CH
2
Cl
2
/n-hexane = 1:1 + 1 drop MeOH, v/v); H NMR (400MHz, CDCl
3
2
.93 (s, 2H, NH), 1.53 (s, 6H, HtBu), 1.55 (s, 30H, HtBu), 3.97 (s, 3H, OCH
3
7
β
2
β
β
β
1
3
β
3
1
3
2
2
nm (3.49); HRMS (MALDI) m/z: 820.4742 (Calcd. for [C56
H
60
N
4
O
2

1530
HETEROCYCLES, Vol. 94, No. 8, 2017
5
-(3’-Carboxymethyl)phenyl-10,20-diphenylporphyrin (5d). Compound 4c (300 mg, 0.55 mmol) was
dissolved in THF (20 mL). The solution was degassed via freeze-pump-thaw cycles, before the flask was
purged with argon. K PO (1.175 g, 5.54 mmol), Pd(PPh (96 mg, 0.08 mmol) and
-methoxycarbonylphenylboronic acid (399 mg, 2.22 mmol) were added. The reaction was stirred for 16
3
4
)
3 4
3
h at 66 °C. The end of the reaction was monitored by TLC. The solvent was removed in vacuo. The
residue was washed with a saturated sodium bicarbonate solution and water. The solvent was removed in
vacuo and the residue recrystallized using CH
2
Cl
2
/MeOH (260 mg, 78%, 0.43 mmol). Mp >300 °C; R
/ n-hexane = 1:1 + 2 drops MeOH, v/v); H NMR (400 MHz, CDCl ) Gꢀꢀ(ppm): –3.02 (s, 2H, NH), 3.96 (s,
H, OCH ), 7.74-7.81 (m, 6H, Ph-H), 7.83 (d, 1H, J = 7.8 Hz, Ar-H), 8.23 (d, 1H, J = 7.6 Hz, Ar-H), 8.38 (d, 1H, J =
.5 Hz, Ar-H), 8.77 (d, 2H, J = 4.7 Hz, H ), 8.88 (s, 1H, Ar-H), 8.90 (d, 2H, J = 4.8 Hz, H ), 9.03 (d, 2H, J = 4.5 Hz,
), 9.36 (d, 2H, J = 4.6 Hz, H ), 10.25 (s, 1H, Hmeso); C NMR (150 MHz, CDCl ): Gꢀꢀ(ppm): 167.5 143.1, 141.8,
Cl ): λmax (log ε)
412 (5.44), 509 (4.09), 543 (3.55), 582 (3.58), 651 nm (3.25); HRMS (MALDI) m/z: 596.2223. (Calcd. for
: 596.2212).
10,20-Bis(3,5-di-tert-butyl)phenyl-5-(3’-carboxyethyl)phenylporphyrinato]zinc(II) (6a). The free
base porphyrin 5a (220 mg, 0.26 mmol) was reacted with zinc(II) acetate and the crude product
purified via column chromatography on silica gel (CH Cl ) followed by recrystallization from
CH Cl /MeOH. Yield: 201 mg (0.22 mmol, 85%) of pink crystals. Mp >300 °C; R : 0.39
CH Cl
CH ), 1.54 (s, 36H, HtBu), 4.43 (q, J = 7.2 Hz, 2H, CH
f
: 0.12
1
(
CH
2
Cl
2
3
3
3
7
β
β
13
H
β
β
3
1
38.6, 134.9, 134.8, 131.2, 129.2, 128.9, 127.9, 127.0, 126.9, 120.0, 119.1, 105.2, 52.5; UV/vis (CH
2
2
=
C
40
H
28
N
4 2
O
[
2
2
2
2
f
1
(
2
2
/n-hexane, 1:1, v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) G (ppm): 1.34 (t, J = 7.2 Hz, 3H,
3
2
), 7.80-7.81 (m, 2H, Ar-H), 8.09-8.10 (m, 4H, Ar-H),
8
.38 (d, J = 7.6 Hz, 1H, Ar-H), 8.46 (d, J = 7.6 Hz, 1H, Ar-H), 8.77 (d, J = 4.6 Hz, 2H, H
), 9.06 (d, J = 4.6 Hz, 2H, H ), 9.33 (d, J = 4.6 Hz, 2H, H ), 10.22 (s, 1H, Hmeso); C
) G (ppm): 166.9, 150.6, 150.5, 149.9, 149.4, 138.7, 138.6, 143.3, 141.5, 138.0,
β
), 8.87-8.88 (m, 1H, Ar-H),
13
8.92 (d, J = 4.6 Hz, 2H, H
β
β
β
NMR (100 MHz, CDCl
3
1
3
34.5, 133.0, 132.4, 131.7, 131.5, 129.9, 129.8, 128.8, 128.7, 126.5, 122.2, 120.9, 119.7, 106.0, 61.1, 35.1,
1.7, 14.3; UV/vis (CH
2
Cl
2
) Omax (log H): 416 (5.76), 543 nm (4.23); LRMS (MALDI) m/z (%): 896 (55)
+
+
+
+
[
M ], 868 (100) [M – C
2
H
5
], 824 (23) [M – C
H
3 5
O
2
], 796 (37) [M – C
5
H
11
2
O ]; HRMS (MALDI) m/z:
8
96.3989 (Calcd for C57
H
60
N
4 2
O
Zn: 896.4008).
5
-Bromo-15-(3’-carboxymethyl)phenyl-10,20-diphenylporphyrin (6c). Porphyrin 5d (450 mg, 0,75
(200 mL). NBS (201 mg, 1.13 mmol) and pyridine (0.15 mL) were added.
The mixture was cooled in an ice bath and stirred for 1 h. The solvent was removed in vacuo after
completion and the residue was filtered through silica gel using CH Cl . The solvent was evaporated and
mmol) was dissolved in CHCl
3
2
2
the desired porphyrin was obtained in 94% yield (478 mg, 0.71 mmol). Mp >300 °C; R
f
: 0.35 (CH
2
Cl /
2
1
n-hexane = 1:1 + 2 drops MeOH, v/v); H NMR (400 MHz, CDCl
3
) Gꢀꢀ(ppm): –2.75 (s, 2H, NH), 2.82 (s, 3H,

HETEROCYCLES, Vol. 94, No. 8, 2017
1531
OCH
3
), 7.77 (d, J = 6.6 Hz, 6H, Ph-H), 7.83 (s, 1H, Ar-H), 8.19 (d, J = 6.6 Hz, 4H, Ph-H), 8.35 (d, J = 6.1 Hz, 1H,
), 8.80 (d, J = 4.3 Hz, 2H, H ), 8.85 (s, 1H, Ar-H),
); C NMR (150 MHz, CDCl ): Gꢀꢀ(ppm): 167.1,
42.0, 141.5, 138.2, 134.6, 134.4, 129.0, 128.8, 127.8, 126.8, 126.6, 120.8, 119.2, 103.1, 52.2; UV/vis
Cl ): λmax (log ε) = 420 (5.53), 518 (4.16), 553(3.87), 595 (3.65), 651 nm (3.59); HRMS (MALDI)
m/z: 674.1351. (Calcd. for C40 Br: 674.1317).
-(3’-Carboxymethyl)phenyl-10,20-diphenyl-15-(trimethylsilyl)ethynyl)porphyrin (6d). Compound
c (200 mg, 0.30 mmol) was dissolved in THF (20 mL) The solution was degassed via three
(PPh (31.2 mg, 0.04 mmol),
CuI (11.3 mg, 0.06 mmol) and trimethylsilylacetylene (1.4 mL, 0.02 mmol) were added. The reaction was
stirred at 45 °C for 16 h and the solvent was removed in vacuo. The residue was dissolved in CH Cl and
filtered through silica gel. After evaporation of the solvent the residue was again filtered through silica gel
with CH Cl :petroleum ether (1:1, v/v). Following this the product was eluted from the silica gel with
and the solvent was evaporated. The crude product was purified by recrystallization from
Ar-H), 8.46 (d, J = 8.3 Hz, 1H, Ar-H), 8.72 (d, J = 3.0 Hz, 2H, H
β
β
13
8
1
.91 (d, J = 4.3 Hz, 2H, H
β
), 9.68 (d, J = 4.3 Hz, 2H, H
β
3
(
CH
2
2
H
27
N
4
O
2
5
6
freeze-pump-thaw cycles, before the flask was purged with argon. PdCl
2
)
3 2
2
2
2
2
CH
2
2
Cl
2
2
CH
Cl
:MeOH giving porphyrin 6d in 127 mg (62%, 0.18 mmol). Mp >300 °C; R
f
: 0.26 (CH
2
Cl /
2
1
n-hexane = 1:1+ 2 drops MeOH, v/v); H NMR (400 MHz, CDCl
3
) Gꢀꢀ(ppm): –2.43 (s, 2H, NH), 0.61 (s, 9H,
TMS-CH
3
), 3.98 (s, 3H, OCH
3
), 7.73-7.81 (m, 6H, Ph-H), 7.83 (d, J = 7.8 Hz, 1H, Ar-H), 8.19 (d, J = 7.7 Hz, 4H,
), 8.77 (d, J = 4.7
); C NMR (150 MHz,
) Gꢀꢀ(ppm): 168.0, 142.3, 139.1, 139.0, 135.4, 135.2, 129.9, 128.6, 127.5, 53.1; UV/vis (CH Cl ):
max (log ε) = 428 (5.66), 527 (4.25), 565 (4.35), 604 (3.83), 661 nm (3.96); HRMS (MALDI) m/z:
Ph-H), 8.35 (d, J = 7.6 Hz, 1H, Ar-H), 8.47 (d, J = 7.9 Hz, 1H, Ar-H), 8.69 (d, J = 4.7 Hz, 2H, H
β
13
Hz, 2H, H
β
), 8.85 (s, 1H, Ar-H), 8.90 (d, J = 4.7 Hz, 2H, H
β
), 9.67 (d, J = 4.7 Hz, 2H, H
β
CDCl
3
2
2
λ
6
29.2635 (Calcd. for C45
-(3’-Carboxymethyl)phenyl-15-(ethynyl)-10,20-diphenylporphyrin (6e). Porphyrin 6d (90 mg, 0.13
Cl and TBAF (1 mL) was added. The mixture was stirred and the reaction
was monitored by TLC. Upon completion the product was filtered through silica gel using CH Cl and
H
36
N
4
O
2
Si: 692.2608).
5
mmol) was dissolved in CH
2
2
2
2
the solvent was removed in vacuo yielding the target compound in quantitative yield (80 mg, 0.13 mmol).
1
Mp >300 °C; R
Gꢀꢀ(ppm): –2.49 (s, 2H, NH), 3.98 (s, 3H, OCH
H, Ar-H), 8.20 (d, J = 6.9 Hz, 4H, Ph-H), 8.36 (d, J = 7.3 Hz, 1H, Ar-H), 8.47 (d, J = 8.2 Hz, 1H, Ar-H), 8.70 (d,
J = 4.6 Hz, 2H, H ), 8.78 (d, J = 4.4 Hz, 2H, H ), 8.85 (s, 1H, Ar-H), 8.92 (d, J = 4.4 Hz, 2H, H ), 9.70 (d, J = 4.7
); C NMR (150 MHz, CDCl ) Gꢀꢀ(ppm): 167.4, 142.4, 141.7, 138.4, 135.1, 134.8, 134.6, 129.3,
28.5, 128.1, 127.0, 122.5, 121.3, 98.1, 89.8, 85.7, 84.8, 84.3, 52.5; UV/vis (CH Cl ): λmax (log ε) = 425
5.82), 524 (4.48), 560 (4.40), 600 (4.06), 657 nm (4.05); HRMS (MALDI) m/z: 620.2181 (Calcd. for
f
: 0.24 (CH
2
Cl
2
/ n-hexane =1:1 + 2 drops MeOH, v/v); H NMR (400 MHz, CDCl
3
)
3
), 4.20 (s, 1H, ethynyl-H), 7.79 (m, 6H, Ph-H), 7.84 (d, J = 7.6 Hz,
1
β
β
β
13
Hz, 2H, H
β
3
1
2
2
(

1532
HETEROCYCLES, Vol. 94, No. 8, 2017
C
42
H
28
N
4
O
2
: 620.2212).
,5-(1,2-Ethyndiyl)bis[15-(3’-carboxymethyl)phenyl-10,20-diphenylporphyrin] (6f). A Schlenk tube
was purged with argon and charged with compound 6e (62 mg, 0.10 mmol in 12 mL THF) followed by
addition of 6c (67.5 mg, 0.10 mmol), TEA (5 mL), AsPh (34 mg, 0.11 mmol) and Pd (dba) (9 mg, 0.01
mmol). The reaction mixture was stirred at 66 °C for 16 h. The solvent was removed in vacuo and the
residue was filtered through silica gel. CH Cl :petroleum ether (1:1, v/v) was used to remove impurities
and then the product was eluted with CH Cl . The crude product was purified by recrystallization from
CH Cl :MeOH and 6f was obtained in 50% yield (60 mg, 0.05 mmol). Mp >300 °C; R : 0.23 (CH Cl );
1H NMR (400 MHz, CDCl
)ꢀG (ppm): –2.01 (s, 4H, NH), 4.00 (s, 6H, OCH ), 7.82 (d, J = 5.5 Hz, 12H, Ph-H),
.87 (d, J = 7.7 Hz, 2H, Ar-H), 8.29 (d, J = 7.3 Hz, 8H, Ph-H), 8.40 (d, J = 7.2 Hz, 2H, Ar-H), 8.50 (d, J = 7.8 Hz,
H, Ar-H), 8.73 (d, J = 4.6 Hz, 4H, H ), 8.83 (d, J = 4.6 Hz, 4H, H ), 8.90 (s, 2H, Ar-H), 9.10 (d, J = 4.5 Hz, 4H,
)ꢀG (ppm): 167.4, 142.4, 141.8, 138.5, 134.9,
34.7, 129.4, 129.1, 128.1, 127.1, 127.0, 121.9, 120.6, 112.0, 52.5; UV/vis (CH Cl ): λmax (log ε) = 406
5.26), 441 (5.18), 473 (5.47), 520 (4.54), 619 (4.69), 713 nm (4.77); HRMS (MALDI) m/z: 1214.4248
Calcd. for C82 : 1214.4268).
5
3
2
3
2
2
2
2
2
2
f
2
2
3
3
7
2
β
β
1
3
H
β
), 10.35 (d, J = 4.6 Hz, 4H, H
β
); C NMR (150 MHz, CDCl
3
1
2
2
(
(
H
54
N
8
O
4
Bis[{5-(3’-carboxyethyl)phenyl}-10,20-bis(3,5-di-tert-butyl)phenylporphyrin-13,15,17-triylato]-
zinc(II) (7a). Porphyrin 6a (20 mg, 0.02 mmol) was dissolved in anhydrous toluene (20 mL) under
argon. The reaction mixture was heated to 50 °C upon the addition of DDQ (25 mg, 0.11 mmol) and
Sc(OTf)
°C and THF (10 mL) was added and stirred for 1 h. The reaction mixture was purified via column
chromatography on alumina (CH Cl ). The solvents were removed in vacuo. Yield: 14 mg (0.01 mmol,
1%) of dark purple solid. Mp >300 °C; R : 0.76 (CH Cl /n-hexane/MeOH, 1:1:0.05, v/v/v, silica gel, 6×3
) G (ppm): 1.35 (t, J = 7.1 Hz, 6H, CH ), 1.45 (s, 72H, HtBu), 4.36 (q, J = 7.1 Hz,
), 7.58-7.65 (m, 18H, Ar-H/H ), 7.68 (d, J = 4.6 Hz, 4H, H ), 7.96 (d, J = 7.5 Hz, 2H,
Ar-H), 8.23 (d, J = 7.5 Hz, 2H, Ar-H), 8.44 (s, 2H, Ar-H); C NMR not obtained due to low solubility of sample;
UV/vis (CH Cl ) Omax (log H): 416 (4.98), 456 (4.54), 578 (4.91), 920 (4.14), 1043 nm (4.36); LRMS
MALDI) m/z (%): 1786 (100) [M ], 1762 (12) [M – C
m/z: 1786.7614 (Calcd for C114 Zn : 1786.7546).
3
(55 mg, 0.11 mmol) with stirring in the absence of light for 18 h. The reaction was cooled to
0
2
2
7
f
2
2
1
cm); H NMR (400 MHz, CDCl
3
3
4
H, CH ), 7.33 (s, 4H, H
2
β
β
β
13
2
2
+
+
+
(
2
H
5
], 1734 (3) [M – C
2
5
H ]; HRMS (MALDI)
H
114
N
8
O
4
2
Bis[5-(3’-benzoic acid)-10,20-bis(3,5-di-tert-butyl)phenylporphyrin-13,15,17-triylato]zinc(II) (7b).
Porphyrin 7a (20 mg, 0.01 mmol) was dissolved in THF (25 mL) and MeOH (25 mL). The reaction
mixture was heated to 70 °C upon the addition of KOH (0.5 g) in H
reaction was cooled to rt and the solvents removed in vacuo. The residue was suspended in CH
mL) and the solution was acidified with 1 M HCl. The product was extracted via CH Cl and 1% MeOH,
2
O (3 mL) with stirring for 3 h. The
2
Cl (100
2
2
2

HETEROCYCLES, Vol. 94, No. 8, 2017
1533
dried over Na
2
SO , and filtered. The solvents were removed in vacuo and the residue suspended in
4
n-hexane. The suspension was filtered to give the title compound. Yield: 12 mg (0.01 mmol, 63%) of a
1
dark purple solid. Mp >300 °C; R
NMR (400 MHz, CDCl
Ar-H/H ), 7.92 (d, J = 8.5 Hz, 2H, Ar-H), 8.29 (d, J = 6.7 Hz, 2H, Ar-H), 8.52 (s, 2H, Ar-H); No C NMR
f
: 0.66 (CH
2
Cl
2
/n-hexane/MeOH, 1:1:0.66, v/v/v, silica gel, 6×3 cm); H
3
+ drop of pyridine) G (ppm): 1.41 (s, 72H, HtBu), 7.07 (s, 4H), 7.50-7.62 (m, 22H,
1
3
β
spectroscopy was possible due to low solubility; UV/vis (THF) Omax (log H): 420 (4.89), 471 (4.50), 563
+
(
4.83), 960 (4.00), 1099 nm (4.35); LRMS (MALDI) m/z (%): 1730 (100) [M ]; HRMS (MALDI) m/z:
1
730.6956 (Calcd for C110
5[3-(6’-Iodohexyl)oxy]phenyl}10,15,20-triphenyl}porphyrin
triphenyl]porphyrin 9 (150 mg, 0.24 mmol) was dissolved in anhydrous DMF (10 mL). K
mg, 2.38 mmol) was added and the solution was stirred at rt for 0.5 h. 1,6-Diiodohexane (0.39 mL,
.38 mmol) was added and the reaction was left to stir for a further 18 h. The solvents were removed
in vacuo and the residue dissolved in CH Cl (100 mL), washed with saturated aqueous NaHCO
brine and H O (2×100 mL, each), dried over Na SO and filtered. The crude product was purified via
column chromatography on silica gel (CH Cl ) followed by recrystallization from n-hexane. Yield:
45 mg (0.17 mmol, 73%) of purple crystals. Mp. 125-126 °C; R : 0.71 (CH Cl /n-hexane, 1:1, v/v,
) G (ppm): –2.79 (br. s, 2H, NH), 1.44-1.54 (m, 4H, CH ),
), 4.13 (t, J = 6.3 Hz, 2H, CH ), 7.30 (d, J = 8.3 Hz, 1H,
Ar-H), 7.61 (t, J = 7.5 Hz, 1H, Ar-H), 7.71-7.80 (m, 11H, Ar/Ph-H), 8.19 (d, J = 7.1 Hz, 6H, Ph-H), 8.83 (app. s,
H
106
N
8
O
4
Zn
2
: 1730.6920).
{
(11).
[5-(3’-Phenol)-10,15,20-
CO (327
2
3
2
2
2
3
,
2
2
4
2
2
1
f
2
2
1
silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
2
1
.80-1.90 (m, 4H, CH ), 3.17 (t, J = 7.0 Hz, 2H, CH
2
2
2
1
3
6
H, H
β
), 8.88 (d, J = 4.8 Hz, 2H, H
β
); C NMR (100 MHz, CDCl
3
) G (ppm): 157.4, 143.4, 142.1, 134.5,
Cl
max (log H): 418 (5.48), 516 (4.07), 550 (3.65), 590 (3.55), 646 nm (3.44); HRMS (MALDI) m/z:
OI: 840.2325.
5{3-(6’-Thioacetate)hexyloxy)phenyl}10,15,20-triphenyl]porphyrin
1
27.7, 127.6, 126.7, 121.0, 120.2, 120.1, 119.8, 114.1, 68.0, 33.4, 30.3, 29.2, 25.1 6.91; UV/vis (CH
2
2
)
O
8
40.2324 (Calcd for C50
H N
41 4
[
(12).
a)
{5-(3’Bromo-
hexyl)oxy)phenyl]-10,15,20-triphenyl}porphyrin 10 (120 mg, 0.15 mmol) was reacted with potassium
thioacetate (104 mg, 0.91 mmol) in anhydrous DMF (10 mL) and the crude product was purified via
column chromatography on silica gel (CH
2
Cl
02 mg (0.13 mmol, 86%) of purple solid. b) Alternatively, the same procedure was used with
3[3-(6’-iodohexyl)oxy)phenyl]10,15,20-triphenyl}porphyrin 11 (120 mg, 0.14 mmol) and potassium
: 0.40 (CH Cl /n-hexane, 1:1, v/v, silica
) G (ppm): –2.79 (br. s, 2H, NH), 1.21-1.29 (m, 2H, CH ), 1.41-1.47 (m,
), 1.81-1.88 (m, 4H, CH ), 2.26 (s, 3H, CH ), 2.85 (t, J = 7.1 Hz, 2H, CH ), 4.12 (t,
), 7.30 (app. d, J = 8.3 Hz, 1H, Ar-H), 7.61 (t, J = 7.9 Hz, 1H, Ar-H), 7.70-7.80 (m,
2
) followed by trituration with isopropyl alcohol. Yield:
1
{
thioacetate (98 mg, 0.86 mmol) to yield 12. Mp 112-115 °C; R
f
2
2
1
gel, 6×3 cm); H NMR (400 MHz, CDCl
H, CH ), 1.54-1.63 (m, 2H, CH
J = 6.4 Hz, 2H, CH
3
2
2
2
2
2
3
2
2

1534
HETEROCYCLES, Vol. 94, No. 8, 2017
1
3
1
1H, Ar/Ph-H), 8.20 (d, J = 6.1 Hz, 6H, Ph-H), 8.83 (app. s, 6H, H
β
), 8.88 (d, J = 4.8 Hz, 2H, H
) G (ppm): 196.0, 157.4, 143.4, 142.2, 134.5, 131.6, 131.3, 127.7, 127.6, 127.4, 126.7, 121.0,
Cl ) Omax (log H):
18 (5.50), 516 (4.07), 550 (3.65), 590 (3.57), 646 nm (3.49); LRMS (MALDI) m/z (%): 788 (100) [M+],
β
); C NMR (100
MHz, CDCl
3
1
4
7
7
20.2, 120.1, 119.9, 114.1, 109.9, 68.0, 30.6, 29.4, 29.2, 29.0, 28.5, 25.6; UV/vis (CH
2
2
+
+
+
45 (23) [M – C
2
H
3
O], 713 (13) [M – C
2
H
3
OS], 630 (32) [M – C H15OS]; HRMS (MALDI) m/z:
8
88.3171 (Calcd for C52
H
44
N
4 2
O
S: 788.3185).
[
5{3-(6’-Thioacetate)hexyloxy)phenyl}10,15,20-triphenylporphyrinato]zinc(II) (13). The free base
porphyrin 12 (200 mg, 0.25 mmol) was reacted with zinc(II)acetate in MeOH and the crude product
purified via column chromatography on silica gel (CH Cl ) followed by trituation with isopropyl
2
2
alcohol. Yield: 160 mg (0.12 mmol, 74%) of purple solid. Mp 125-127 °C; R : 0.53
f
1
(
CH
m, 2H, CH
7.1 Hz, 2H, CH
Ar-H), 7.71-7.80 (m, 11H, Ar/Ph-H), 8.20 (d, J = 6.9 Hz, 6H, Ph-H), 8.93 (s, 6H, H
13C NMR (100 MHz, CDCl
) G (ppm): 195.9, 157.3, 150.2, 150.1, 144.0, 134.4, 132.0, 131.9, 127.5,
27.4, 127.3, 126.5, 121.1, 121.0, 120.9, 114.0, 68.0, 30.5, 29.4, 29.2, 29.0, 28.5, 25.6; UV/vis (CH Cl
max (log H): 420 (5.62), 548 (4.18), 586 nm (3.42); LRMS (MALDI) m/z (%): 850 (100) [M ], 775 (5)
2
Cl
2
/n-hexane/MeOH, 1:1:0.1, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) G (ppm): 1.21-1.28
), 2.23 (s, 3H, CH ), 2.81 (t, J
), 7.29 (d, J = 8.1 Hz, 1H, Ar-H), 7.60 (t, J = 8.1 Hz, 1H,
), 8.98 (d, J = 4.6 Hz, 2H, H );
(
2
), 1.40-1.46 (m, 2H, CH
2
), 1.54-1.61 (m, 2H, CH
2
), 1.81-1.88 (m, 4H, CH
2
3
=
2
), 4.11 (t, J = 6.4 Hz, 2H, CH
2
β
β
3
1
2
2
)
+
O
+
+
[
M – C
2
H
3
OS], 692 (11) [M – C
8
H
15OS]; HRMS (MALDI) m/z: 850.2289 (Calcd for C52
H
42
N
4
O SZn:
2
850.2320).
5,10,15,20-Tetrakis[methyl-5’-(m-phenoxy)pentanoate]porphyrin
(15).
5,10,15,20-Tetrakis(3’-
hydroxy)phenylporphyrin 14 (400 mg, 0.59 mmol) was dissolved in anhydrous DMF (12 mL) under
argon. K CO (976 mg, 7.07 mmol) was added and the solution was stirred at rt for 0.5 h. Methyl
-bromovalerate (1.01 mL, 7.072 mmol) was added and the reaction was stirred for 24 h at room
temperature. The solvents were removed in vacuo, the residue dissolved in CH Cl , washed with
saturated aqueous NaHCO (4×100 mL), brine (2×100 mL) and water (2×100 mL), dried over Na SO
and filtered. The solvents were removed in vacuo and the residue purified via column
chromatography on silica gel (CH Cl ). The solvents were removed to yield an oil-like, purple
2
3
5
2
2
3
2
4
,
2
2
product. Yield: 512 mg (0.45 mmol, 77%). Mp 83-85 °C; R
f
: 0.48 (CH
2
Cl
2
/n-hexane/MeOH, 1:1:0.5,
),
), 7.35 (dd, J = 8.3, 1.8 Hz, 4H,
Ar-H), 7.67 (t, J = 8.0 Hz, 4H, Ar-H), 7.81 (app. s, 4H, Ar-H), 7.85 (d, J = 7.4 Hz, 4H, Ar-H), 8.94 (s, 8H, H );
13C NMR (100 MHz, CDCl
) G (ppm): 173.9, 157.3, 143.5, 127.7, 127.5, 121.0, 119.9, 114.1, 67.6, 51.6,
3.8, 28.8, 21.8; UV/vis (CH Cl ) Omax (log H): 420 (5.60), 516 (4.20), 550 (3.76), 590 (3.68), 648 nm
1
v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) G (ppm): –2.76 (br. s, 2H, NH), 1.94-1.96 (m, 16H, CH
2
2
.47 (t, J = 6.8 Hz, 8H, CH
2
), 3.70 (s, 12H, CH
3
), 4.21 (t, J = 5.8 Hz, 8H, CH
2
β
3
3
2
2

HETEROCYCLES, Vol. 94, No. 8, 2017
1535
+
(
3.58); LRMS (MALDI) m/z (%): 1134 (100) [M ]; HRMS (MALDI) m/z: 1134.4949 (Calcd for
C
68
H
70
N
4
O
12: 1134.4990).
[5,10,15,20-Tetrakis{methyl-5’-(m-phenoxy)pentanoate}porphyrinato]zinc(II) (16). 5,10,15,20-
Tetrakis[methyl-5’-(m-phenoxy)-pentanoate]porphyrin 15 (200 mg, 0.18 mmol) was reacted with
zinc(II) acetate in MeOH and the crude product was purified via column chromatography on silica gel
(
CH
CH
m, 16H, CH
.4, 1.8 Hz, 4H, Ar-H), 7.65 (t, J = 8.0 Hz, 4H, Ar-H), 7.80 (app. s, 4H, Ar-H), 7.84 (d, J = 7.3 Hz, 4H, Ar-H),
2
Cl
2
/MeOH, 99:1, v/v). Yield: 187 mg (0.16 mmol, 89%) of a purple oil. Mp 83-85 °C; R
f
: 0.40
) G (ppm): 1.90-1.98
), 4.18 (t, J = 5.6 Hz, 8H, CH ), 7.34 (dd, J =
1
(
2
Cl
2
/n-hexane/MeOH, 1:1:0.5, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
(
2
), 2.45 (t, J = 7.0 Hz, 8H, CH ), 3.67 (s, 12H, CH
2
3
2
8
13
9
.02 (s, 8H, H
β
); C NMR (100 MHz, CDCl ) G (ppm): 173.9, 157.2, 150.1, 144.1, 132.0, 127.5, 127.4,
3
1
20.9, 114.0, 67.6, 51.6, 33.7, 28.8, 21.7; UV/vis (CH
2
Cl
2
) Omax (log H): 420 (5.71), 550 (4.29), 584 nm
+
+
(
3.49); LRMS (MALDI) m/z (%): 1196 (100) [M ], 736 (7) [M – C24
H
44
8
O ]; HRMS (MALDI) m/z:
1
196.4116 (Calcd for C68
5,10,15,20-Tetrakis[methyl-4’(m-phenoxy)butanoate]porphyrinato]nickel(II) (22). [5,10,15,20-
Tetrakis(3’-hydroxy)phenylporphyrinato]nickel(II) 17 (200 mg, 0.27 mmol) was dissolved in
anhydrous DMF (10 mL) under argon. K CO (450 mg, 3.26 mmol) was added and the reaction
mixture stirred for 0.5 h at rt. The reaction was stirred for a further 24 h upon the addition of methyl
-bromobutanoate 20 (0.41 mL, 3.26 mmol). The solvents were removed in vacuo, the residue
dissolved in CH Cl (100 mL), followed by washing with saturated aqueous NaHCO , brine and H
3×100 mL, each). The organic extracts were combined, dried over aqueous Na SO and filtered. The
solvents were removed in vacuo and the residue purified via column chromatography on silica gel
H
68
N
4
O12Zn: 1196.4125).
[
2
3
4
2
2
3
2
O
(
2
4
(
CH
purple crystals. Mp 86-88 °C; R
NMR (400 MHz, CDCl ) G (ppm): 2.12-2.19 (m, 8H, CH
t, J = 6.0 Hz, 8H, CH ), 7.20-7.23 (m, 4H, Ar-H), 7.50-7.57 (m, 8H, Ar-H), 7.59-7.61 (m, 4H, Ar-H), 8.76 (s,
); C NMR (100 MHz, CDCl ) G (ppm): 173.6, 157.3, 142.5, 142.2, 132.1, 27.7, 126.8, 120.2,
2
Cl
2
) followed by recrystallization from CH
2
Cl
2
/MeOH. Yield: 173 mg (0.15 mmol, 56%) of
1
f
: 0.56 (CH Cl
2
2
/n-hexane/MeOH, 1:1:0.4, v/v/v, silica gel, 6×3 cm); H
3
2
), 2.56 (t, J = 7.2 Hz, 8H, CH
2
), 3.65 (s, 12H, CH ), 4.12
3
(
2
13
8
H, H
β
3
1
18.7, 114.0, 66.9, 51.6, 30.6, 24.7; UV/vis (CH
2
Cl ) Omax (log H): 414 (5.41), 528 nm (4.27); LRMS
2
+
(
MALDI) m/z (%): 1134 (100) [M ]; HRMS (MALDI) m/z: 1134.3539 (Calcd for C64
H
60
N O12Ni:
4
1
134.3561).
5,10,15,20-Tetrakis{methyl-5’-(m-phenoxy)pentanoate}porphyrinato]nickel(II) (23). [5,10,15,20-
Tetrakis(3’-hydroxy)phenylporphyrinato]nickel(II) 17 (200 mg, 0.27 mmol), K CO (450 mg, 3.26
mmol), and methyl 5-bromovalerate 21 (0.47 mL, 3.26 mmol) were reacted as described for
compound 22 to yield 202 mg (0.17 mmol, 62%) of purple crystals. Mp 82-84 °C; R : 0.52
[
2
3
f

1536
HETEROCYCLES, Vol. 94, No. 8, 2017
1
(
CH
2
Cl
2
/n-hexane/MeOH, 1:1:0.5, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) G (ppm): 1.85-1.87
), 7.20-7.23 (m,
) G (ppm): 173.8, 157.4,
(m, 16H, CH
2
), 2.40 (t, J = 6.8 Hz, 8H, CH
2
), 3.64 (s, 12H, CH
3
), 4.08 (t, J = 5.8 Hz, 8H, CH
2
1
3
4
1
H, Ar-H), 7.51-7.61 (m, 12H, Ar-H), 8.77 (s, 8H, H
β
); C NMR (100 MHz, CDCl
3
42.5, 142.2, 132.1, 127.7, 126.7, 120.1, 118.8, 114.1, 67.5, 51.5, 33.7, 28.7, 21.7; UV/vis (CH
2
Cl ) Omax
2
+
(
log H): 416 (5.13), 528 nm (3.99); LRMS (MALDI) m/z (%): 1190 (100) [M ]; HRMS (MALDI) m/z:
1
190.4165 (Calcd for C68
H
68
N
4
O12Ni: 1190.4187).
[5,10,15,20-Tetrakis{4’(m-phenoxy)butanoic acid}porphyrinato]nickel(II) (24). [5,10,15,20-
Tetrakis{methyl-4’(m-phenoxy)butanoate}porphyrinato]nickel(II) 22 (100 mg, 0.09 mmol) was
dissolved in THF (50 mL). NaOH (16 g in 50 mL EtOH) was added and the solution was heated to
reflux with stirring for 24 h. 1 M HCl was added after the reaction was cooled to rt. The organic layer
was extracted with CH
solvent was removed in vacuo and the residue was recrystallized from CH
0.06 mmol, 65%) of red crystals. Mp 145-147 °C; R : 0.67 (CH Cl /n-hexane/MeOH, 2:1:0.6, v/v/v,
, 30:1, v/v) G (ppm): 2.16-2.24 (m, 8H, CH ), 2.58 (t, J
), 7.20-7.23 (m, 4H, Ar-H), 7.49-7.60 (m, 12H, Ar-H),
), 11.06 (br. S, 4H, COOH); C NMR (100 MHz, CDCl /pyridine-d , 30:1, v/v) G (ppm):
2
Cl
2
, washed with H
2
O (2×250 mL) and dried over Na
2
SO
4
. After filtration, the
2
Cl
2
/MeOH. Yield: 62 mg
(
f
2
2
1
silica gel, 6×3 cm); H NMR (400 MHz, CDCl
7.0 Hz, 8H, CH ), 4.16 (t, J = 6.1 Hz, 8H, CH
.76 (s, 8H, H
3
/pyridine-d
5
2
=
2
2
13
8
1
β
3
5
76.1, 157.5, 142.8, 142.1, 132.5, 127.7, 126.7, 120.3, 118.8, 114.1, 67.2, 31.0, 24.9; UV/vis (CH
2
Cl )
2
+
O
max (log H): 414 (5.40), 528 nm (4.26); LRMS (MALDI) m/z (%): 1078 (100) [M ]; HRMS (MALDI)
m/z: 1078.2903 (Calcd for C60
5,10,15,20-Tetrakis{5’-(m-phenoxy)pentanoic acid}porphyrinato]nickel(II) (25). [5,10,15,20-
Tetrakis{methyl-4’(m-phenoxy)pentanoate}porphyrinato]nickel(II) 23 (150 mg, 0.13 mmol) treated
H
52
N
4
O12Ni: 1078.2935).
[
under the conditions given for 24 gave 102 mg (0.09 mmol, 71%) of red crystals. Mp 130-131 °C; R :
f
1
0
.68 (CH
0:1, v/v) G (ppm): 1.81-1.89 (m, 16H, CH
.19-7.22 (d, J = 6.9 Hz, 4H, Ar-H), 7.48-7.57 (m, 12H, Ar-H), 8.76 (s, 8H, H
CDCl /pyridine-d , 30:1, v/v) G (ppm): 176.2, 157.5, 142.7, 142.1, 132.3, 127.6, 126.6, 120.1, 188.8,
14.1, 67.7, 34.1, 28.8, 21.8; UV/vis (CH Cl ) Omax (log H): 416 (5.29), 528 nm (4.15); LRMS (MALDI)
m/z (%): 1134 (100) [M ]; HRMS (MALDI) m/z: 1134.3508 (Calcd for C64 12Ni: 1134.3561).
10,20-Bis(3,5-di-tert-butyl)phenyl-5-{methyl-5’-(m-phenoxy)pentanoate}]porphyrin (27). [10,20-
Bis(3,5-di-tert-butyl)phenyl-5-(3’-hydroxy)phenyl]porphyrin 26 (240 mg, 0.31 mmol) was reacted
with K CO (213 mg, 1.54 mmol) in anhydrous DMF (10 mL) for 0.5 h, followed by the addition of
methyl 5-bromovalerate (0.22 mL, 1.54 mmol) and subsequent stirring for 18 h. The crude product
was purified via column chromatography on silica gel (CH Cl /n-hexane, 1:1, v/v) followed by
2
Cl
2
/n-hexane/MeOH, 1:1:0.7, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
/pyridine-d
), 4.09 (t, J = 5.8 Hz, 8H, CH ),
); C NMR (100 MHz,
5
,
3
2
), 2.42 (t, J = 6.9 Hz, 8H, CH
2
2
1
3
7
β
3
5
1
2
2
+
H
60
N O
4
[
2
3
2
2

HETEROCYCLES, Vol. 94, No. 8, 2017
1537
recrystallization from CH
300 °C; R : 0.80 (CH Cl
CDCl ) G (ppm): –2.89 (br. s, 2H, NH), 1.59 (s, 36H, HtBu), 2.04-2.06 (m, 4H, CH
.78 (s, 3H, CH ), 4.31 (t, J = 5.3 Hz, 2H, CH ), 7.28 (m, 1H, Ar-H), 7.30 (m, 1H, Ar-H), 7.84-7.85 (m,
H, Ar-H), 8.14-8.16 (m, 6H, Ar-H), 8.94 (d, J = 4.7 Hz, 2H, H ), 8.98 (d, J = 4.8 Hz, 2H, H ), 9.10 (d, J
4.8 Hz, 2H, H ), 9.37 (d, J = 4.8 Hz, 2H, H ), 10.24 (s, 1H, Hmeso); C NMR (100 MHz, CDCl ) G
ppm): 174.2, 158.7, 148.9, 140.8, 135.5, 135.2, 130.1, 121.0, 120.9, 120.2, 112.5, 104.5, 67.7, 51.7, 35.1,
3.8, 31.8, 28.9, 21.9; UV/vis (CH Cl ) Omax (log H): 416 (5.54), 512 (4.10), 548 (3.67), 586 (3.63), 642
2
Cl
2
/n-hexane. Yield: 211 mg (0.24 mmol, 77%) of purple crystals. Mp
1
>
f
2
2
/n-hexane/MeOH, 1:1:0.05, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz,
3
2
), 2.58 (t, J = 6.8 Hz, 2H, CH ),
2
3
2
3
2
β
β
1
3
=
β
β
3
(
3
2
2
+
+
+
nm (3.57); LRMS (MALDI) m/z (%): 892 (100) [M ], 747 (18) [M – C
7
H
14
O
3
], 731 (28) [M –
+
C
8
H
17
O
3
], 717 (32) [M – C
9
H
20
O
3
]; HRMS (MALDI) m/z: 892.5264 (Calcd for C60
H
68
N
4 3
O
: 892.5291).
[
10,20-Bis(3,5-di-tert-butyl)phenyl-5-[methyl-5’-(m-phenoxy)pentanoate]porphyrinato]zinc(II) (28).
The free base 27 (180 mg, 0.20 mmol) was reacted with zinc(II) acetate in MeOH. The crude product
was purified via column chromatography on silica gel (CH Cl /n-hexane, 1:1, v/v). Yield: 185 mg
Cl /n-hexane/MeOH, 1:1:0.1, v/v/v, silica
), 2.53 (t, J = 6.6
), 7.24 (s, 1H, Ar-H), 7.27 (s, 1H, Ar-H),
.83 (app. s, 2H, Ar-H), 8.14 (app. s, 6H, Ar-H), 9.04 (dd, J = 4.6 Hz, 4H, H ), 9.17 (d, J = 4.6 Hz, 2H,
), 10.27 (s, 1H, Hmeso); C NMR (100 MHz, CDCl ) G (ppm): 173.6, 158.1,
50.0, 149.6, 149.4, 148.2, 141.2, 134.9, 132.5, 131.6, 131.5, 131.1, 129.4, 121.5, 120.7, 120.3, 112.0,
2
2
(
0.19 mmol, 96%) of pink solid. Mp >300 °C; R
f
: 0.73 (CH
2
2
1
gel, 6×3 cm); H NMR (400 MHz, CDCl
3
) G (ppm): 1.56 (s, 36H, HtBu), 1.95-2.05 (m, 4H, CH
2
Hz, 2H, CH
2
), 3.74 (s, 3H, CH
3
), 4.30 (t, J = 5.8 Hz, 2H, CH
2
7
β
1
3
H
β
), 9.43 (d, J = 4.8 Hz, 2H, H
β
3
1
1
05.2, 67.2, 51.2, 34.6, 33.4, 31.3, 28.5, 26.4; UV/vis (CH
2
Cl ) Omax (log H): 416 (5.69), 544 (4.28), 582
2
+
nm (3.48); LRMS (MALDI) m/z (%): 954 (100) [M ]; HRMS (MALDI) m/z: 954.4426 (Calcd for
C
60
H
66
N
4
O Zn: 954.4426).
3
Bis[10,20-Bis(3,5-di-tert-butyl)phenyl-5-{methyl-5’-(m-phenoxy)pentanoate}porphyrin-13,15,17-
triylato]zinc(II) (29). Porphyrin 28 (100 mg, 0.10 mmol) was reacted with DDQ (118 mg, 0.52 mmol)
and Sc(OTf)
crude product was purified via column chromatography on alumina (CH
followed by isolation of the triply-fused dimer using CH Cl /2% MeOH. Yield: 56 mg (0.03 mmol,
/n-hexane/MeOH, 1:1:0.5, v/v/v, silica gel, 6×3
, 20:1, v/v) G (ppm): 1.38 (s, 72H, HtBu), 1.88-1.91 (m, 8H, CH ), 2.44 (t,
), 4.09 (app. m, 4H, CH ), 6.99 (d, J = 8.2 Hz, 4H, Ar-H), 7.04 (s,
), 7.52 (m, 16H, Ar-H), 7.60-7.63 (m, 4H, H
, 20:1, v/v) G (ppm): 173.5, 147.9, 133.3, 129.9, 127.8, 126.2, 120.0, 112.4, 67.0, 51.1,
4.4, 33.3, 31.2, 28.4, 21.3; UV/vis (CH Cl ) Omax (log H): 420 (5.25), 474 (4.86), 582 (5.19), 966 (4.49),
3
(258 mg, 0.52 mmol) in anhydrous toluene (30 mL) at 50 °C in the dark for 3 h. The
2
Cl /n-hexane, 1:1, v/v),
2
2
2
5
4%) of purple crystals. Mp >300 °C; R
f
: 0.66 (CH
2
Cl
2
1
cm); H NMR (400 MHz, CDCl
3
/pyridine-d
), 3.67 (s, 6H, CH
), 7.47 (d, J = 4.3 Hz, 4H, H
/pyridine-d
5
2
J = 6.6 Hz, 4H, CH
H, H
CDCl
2
3
2
13
4
β
β
β
); C NMR (100 MHz,
3
5
3
2
2

1538
HETEROCYCLES, Vol. 94, No. 8, 2017
+
1
100 nm (4.68); LRMS (MALDI) m/z (%): 1902 (100) [M ]; HRMS (MALDI) m/z: 1902.8446 (Calcd
for C120
H
126
N
8
O
6
Zn : 1902.8383).
2
Bis[10,20-Bis(3,5-di-tert-butyl)phenyl-5-{methyl-5’-(m-phenoxy)pentanoate}porphyrin-15-ylato]-
zinc(II) (30). Isolated as fraction 1 during the synthesis of 29. Yield: 45 mg (45%, 0.02 mmol) of a
1
red-purple solid. Mp >300 °C; R
NMR (400 MHz, CDCl ) G (ppm): 1.42 (s, 72H, HtBu), 2.03-2.04 (m, 8H, CH
s, 6H, CH ), 4.30 (t, J = 5.3 Hz, 4H, CH ), 7.29 (d, J = 8.6 Hz, 4H, Ar-H), 7.66-7.67 (m, 4H, Ar-H),
.06-8.07 (m, 8H, Ar-H), 8.11 (d, J = 4.7 Hz, 4H, H ), 8.18 (d, J = 8.4 Hz, 4H, Ar-H), 8.68 (d, J = 4.7 Hz,
H, H ), 9.00 (d, 4H, J = 4.7 Hz, H ), 9.04 (d, J = 4.7 Hz, 4H, H
74.0, 158.6, 154.8, 150.9, 150.3, 150.0, 148.4, 141.7, 135.4, 135.3, 132.2, 132.0, 131.9, 129.6, 123.2,
f
: 0.69 (CH
2
Cl
2
/n-hexane/MeOH, 1:1:0.05, v/v/v, silica gel, 6×3 cm); H
3
2
), 2.54 (t, J = 7.0 Hz, 4H, CH ), 3.74
2
(
3
2
8
4
1
1
β
13
β
β
β
); C NMR (100 MHz, CDCl ) G (ppm):
3
21.5, 120.7, 119.3, 112.6, 67.7, 51.6, 34.9, 33.8, 31.6, 28.9, 21.8; UV/vis (CH
2
Cl
2
) Omax (log H): 420
+
(
5.45), 458 (5.50), 562 (4.83), 602 nm (4.01); LRMS (MALDI) m/z (%): 1910 (100) [M ]; HRMS
(
MALDI) m/z: 1906.8774 (Calcd for C120
H
130
N
8
O
6
Zn : 1906.8696).
2
Bis[10,20-Bis(3,5-di-tert-butyl)phenyl-5-{5’-(m-phenoxy)pentanoic
triylato]zinc(II) (31). Compound 29 (40 mg, 0.02 mmol) dissolved in THF (25 mL) and MeOH (25
mL) was reacted with KOH (1.2 g, 21.4 mmol) in H O (10 mL) at 70 °C for 3 h. The reaction was
cooled to rt and the solvents removed in vacuo. The residue was suspended in CH Cl (100 mL) and
acidified with 1 M HCl. The crude product was extracted using CH Cl /MeOH (99:1, v/v) and
recrystallized from n-hexane. Yield: 34 mg (0.02 mmol, 86%) of purple crystals. Mp >300 °C; R : 0.57
, 20:1,
), 4.15 (t, J = 5.6 Hz, 4H,
/Ar-H); C NMR (100 MHz, CDCl /pyridine-d
0:1, v/v) G (ppm): 176.3, 158.4, 153.3, 148.4, 140.7, 134.3, 133.7, 130.7, 128.2, 126.7, 120.4, 112.8,
acid}porphyrin-13,15,17-
2
2
2
2
2
f
1
(
CH
v/v) G (ppm): 1.42 (s, 72H, HtBu), 1.96-1.99 (m, 8H, CH
CH ), 7.01-7.10 (m, 8H, H /Ar-H), 7.51-7.63 (s, 24H, H
2
Cl
2
/n-hexane/MeOH, 1:1:0.5, v/v/v, silica gel, 6×3 cm); H NMR (400 MHz, CDCl
3
/pyridine-d
5
2
), 2.53 (t, J = 6.8 Hz, 4H, CH
2
1
3
2
β
β
3
5
,
2
6
7.7, 34.9, 34.3, 31.7, 29.0, 21.9; UV/vis (CH
2
Cl
2
) Omax (log H): 420 (5.20), 474 (4.80), 582 (5.13), 966
+
(
(
4.42), 1100 nm (4.61); LRMS (MALDI) m/z (%): 1874 (100) [M ]; HRMS (MALDI) m/z: 1874.8044
Calcd for C118
H
122
N
8
O
6
Zn : 1874.8070).
2
Crystal structure determination of 6a. Crystals were grown following the protocol developed by
3
2
Hope. Diffraction data for the compound was collected on a Bruker APEX 2 DUO CCD diffractometer
using Incoatec IPS CuK (λ = 1.54178 Å) radiation. Crystals were mounted on a MiTeGen MicroMount
D
and collected at 100(2) K using an Oxford Cryosystems Cobra low-temperature device. Data were
collected using omega and phi scans and corrected for Lorentz and polarization effects using the APEX
software suite.33 The structure was solved with Direct Methods and refined against │F │ with the
2
2
34a
program OLEX using all data.
Non-hydrogen atoms were refined with anisotropically thermal

HETEROCYCLES, Vol. 94, No. 8, 2017
1539
parameters. Hydrogen atoms were generally placed in geometrically calculated positions and refined
using a riding model. All images were rendered using XP in SHELXTL.34b,c
Zn (M = 898.46
/n, a = 26.0025(13) Å, b = 5.7174(3) Å, c = 33.5335(19) Å, βꢀ=
C
57
H
60
N
4
O
2
-1
g.mol ): monoclinic, space group P2
1
3
-1
-3
1
00.215(4), V = 4906.3(5) Å , Z= 4, T = 99.97K, μ(CuK
D
) = 1.040 mm , Dcalc = 1.216 g cm , 27214
reflections measured (3.976° ≤ 2θ≤ 122.518°), 5281 unique (Rint = 0.1159, Rsigma = 0.1053) which were
used in all calculations. The final R was 0.0615 (I > 2σ(I)) and wR was 0.1615 (all data).
Crystal structure determination of 13. General details as given for 6a. C53 SZn (M =971.69
1
2
H43Cl
3
N
4
O
2
-1
g.mol ): triclinic, space group P1, α = 10.7348(4) Å, b = 10.9532(4) Å, c = 11.2018(4) Å, αꢀ=
3
7
3.7480(10)°, βꢀ= 80.1710(10)°, γ = 74.9300(10)°, V = 1214.16(8) Å , Z = 1, T= 100.0K, μ(CuK
D
) =
-1
-3
2
.971 mm , Dcalc = 1.329 g.cm , 29482 reflections measured (8.268° ≤ 2θ≤ 137.262°), 8543 unique (Rint
0.0312, Rsigma = 0.0299) which were used in all calculations. The final R was 0.0564 (I > 2σ(I)) and
wR was 0.1546 (all data). The structure was refined as a refined as a two-component inversion twin.
=
1
2
Solvent chloroform molecules were modeled over two positions with a 47:53% occupancy.
CCDC 1549910 and 1549911 contain the supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
ACKNOWLEDGEMENTS
This work was supported by a grant from Science Foundation Ireland (SFI IvP 13/IA/1894).
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