meso,meso-linked and triply fused diporphyrins with mixed-metal ions: Synthesis and electrochemical investigations

Article abstract of DOI:10.1002/ejoc.200700505

A novel series of biaryl-type, meso,meso-linked and planar, triply fused diporphyrin derivatives was prepared and fully characterized together with the corresponding monoporphyrin control compounds. They feature peripheral meso-3-cyanophenyl and meso-3,5-

Full text of DOI:10.1002/ejoc.200700505

FULL PAPER
DOI: 10.1002/ejoc.200700505
meso,meso-Linked and Triply Fused Diporphyrins with Mixed-Metal Ions:
Synthesis and Electrochemical Investigations
[
a]
[a]
[b,c]
[b]
Leslie-Anne Fendt, Hongjuan Fang, Marta E. Plonska-Brzezinska,
Sheng Zhang,
[
a]
[a]
[b]
[a]
Fuyong Cheng, Christophe Braun, Luis Echegoyen,* and François Diederich*
Dedicated to Professor Dr. Gerard van Koten on the occasion of his 65th birthday
Keywords: Diporphyrins / Electrochemistry / UV/Vis spectroscopy / Electrostatic interactions / Conjugation
A novel series of biaryl-type, meso,meso-linked and planar,
triply fused diporphyrin derivatives was prepared and fully
characterized together with the corresponding monoporphy-
rin control compounds. They feature peripheral meso-3-cya-
nophenyl and meso-3,5-cyanophenyl groups, which have
previously been shown to undergo transformation into ma-
lonates without perturbation of the porphyrin core and sub-
sequent Bingel addition to fullerene C60. The tetrapyrrolic
metal binding sites in the diporphyrin arrays are either com-
tially metallated porphyrin rings was systematically investi-
gated by UV/Vis spectroscopy and electrochemistry. Cyclic
voltammetry and differential pulse voltammetry reveal that
electronic communication in the diporphyrin arrays varies
strongly with the mode of connection (meso,meso-linked or
triply fused), the nature of the bound metal ion, and the
number of peripheral cyano groups. The electrochemical
HOMO–LUMO gap in both series of diporphyrins is strongly
but differentially affected by the choice of the inserted metal
ions.
II
II
plexed to two Zn or Cu ions, or, in a mixed coordination,
to one Cu and one ZnII ion; alternatively, one or both sites
remain unoccupied. The interaction between the differen-
II
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
triply fused oligoporphyrins with C60 and studied in detail
the electrochemical properties of the resulting dyads,
thereby demonstrating their exceptional multicharge stor-
Introduction
[
5]
age capacity. In the course of that work, we became inter-
ested in investigating the properties of mixed-metal dipor-
In recent years, Osuka and coworkers introduced several
families of oligoporphyrin arrays in which individual por-
phyrin rings are linked together either by single bonds in a
biaryl-type fashion (meso,meso-linked) or by triple fusion
with formation of planar, sheet-like structures.[ They are
among the most promising new scaffolds for advanced ma-
terials applications,[ and consequently, their optical and
photophysical properties are increasingly being investi-
[6]
phyrins and, ultimately, the interactions of the differen-
tially metallated porphyrins with fullerenes both in solu-
[7]
[8]
tion and on surfaces. Here, we describe the synthesis
1]
[9–13]
and study of a series of mixed-metal diporphyrins
that
bear meso-3-cyanophenyl and meso-3,5-dicyanophenyl
rings in their periphery for further transformation into ma-
lonates and subsequent conjugation to fullerenes by Bingel
2]
[
3,4]
gated.
We have conjugated singly meso,meso-linked and
[5]
addition. We analyze the electronic communication be-
tween differentially metallated porphyrin ring centers in the
arrays and show its strong dependence on the nature of the
linkage. Electrochemistry is the method of choice for such
investigation; despite the fact that a very large number of
covalent and supramolecular oligoporphyrin assemblies
have been prepared as models for photosynthetic reaction
centers, light-harvesting antenna complexes, or photonic
devices, only a limited number of electrochemical studies
[
a] Laboratorium für Organische Chemie, ETH-Hönggerberg,
HCI,
8
093 Zürich, Switzerland
Fax: +41-44-632-1109
E-mail: diederich@org.chem.ethz.ch
b] Department of Chemistry, Clemson University,
Clemson, SC 29634, USA
[
[
Fax: +1-864-656-6613
E-mail: luis@clemson.edu
c] Institute of Chemistry, University of Bialystok,
[4,5b–5d,14–17]
on oligoporphyrin arrays have been described.
Figure 1 shows all diporphyrins (6–21) and monomeric con-
trols (1–5) included in this investigation.
1
5-399 Bialystok, Poland
Supporting information for this article is available on the
WWW under http://www.eurjoc.org or from the author.
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4659

L. Echegoyen, F. Diederich et al.
FULL PAPER
Figure 1. Overview of meso,meso- (m,m-) singly linked and triply fused (tf) diporphyrins and monomeric controls included in this investiga-
tion.
n
Porphyrins are abbreviated as P , where n represents the number of incorporated porphyrin units.
Results and Discussion
Synthesis of Monoporphyrin Derivatives
phthalonitrile[18] and bis(pinacolato) diboron (Scheme 1).
II
Tetracyano-substituted Zn porphyrin (CN) ZnP (3) was Demetallation with TFA provided the free-base porphyrin
4
synthesized in a Suzuki cross-coupling between diiodopor- (CN)
H
P (5), which was remetallated with Cu(OAc)
in
2
4
2
[
5b,5d]
phyrin 22
and boronate 23, obtained from 5-bromo- MeOH/CHCl to give (CN) CuP (4).
3
4
4660
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
Scheme 1. Synthesis of monoporphyrins: (a) 23; Cs
Pd(PPh )]; PhMe; 140 °C; 20 h; 70%; (b) TFA; CHCl ; 20 °C; 2 h;
quant.; (c) Cu(OAc) ; MeOH/CHCl , 1:1; ∆; 2 h; 92%. TFA = tri-
2 3
CO ;
[
3
3
2
3
fluoroacetic acid, Ar = 3,5-bis(tert-butyl)phenyl.
Synthesis of meso,meso-Linked Diporphyrin Derivatives
I
[1a,19]
Ag -promoted oxidative coupling
of dicyanopor-
phyrin 24, obtained by cross-coupling between the corre-
sponding iodoporphyrin[ and 23, afforded the bis(zinc)
derivative m,m-(CN) Zn P (8) (Scheme 2). Demetallation
5d]
4
2 2
Scheme 2. Synthesis of symmetric meso,meso-linked diporphyrins:
(a) AgPF ; CHCl ; ∆; 18 h; 85 %; (b) conc. HCl/MeOH, 1:1;
provided m,m-(CN) H P (13) and subsequent remetalla-
4
4 2
6
3
tion gave m,m-(CN) Cu P (9). The latter compound can- 10 min; 20 °C; quant.; (c) Cu(OAc) ; MeOH/CHCl , 1:1; ∆; 20 h;
4
2
2
2
3
not be prepared by oxidative dimerization of the corre- quant. Ar = 3,5-bis(tert-butyl)phenyl.
II
sponding Cu monoporphyrin; rather, such coupling leads
to single-bond connection between the β positions, which
was explained by molecular orbital considerations.
[
15c]
ply fused diporphyrins starting from monoporphyrins
[
2a,20]
(Scheme 4).
Thus, coupling of monoporphyrin 24 af-
The synthesis of hybrid meso,meso-diporphyrins with two
different metal ions or with one free-base tetrapyrrolic site
was best accomplished by forming the bridging C–C single
forded tf (CN) Zn P (16). Alternatively, the latter was also
4
2 2
prepared by oxidation of meso,meso-diporphyrin 8 with
DDQ. Oxidation of m,m-(CN) ZnH P (10) with DDQ af-
bond by Suzuki cross-coupling.[ For this purpose, Zn
19]
II
4
2 2
forded the tf (CN) ZnH P hybrid system 18, and metalla-
monoporphyrin 24 was iodinated (I , AgPF ) to give iodo-
4
2 2
2
6
tion with Cu(OAc) provided mixed-metallated tf (CN) -
porphyrin 25. Demetallation afforded 26, whereas coupling
of 25 with pinacolborane yielded 27. Suzuki cross-coupling
of iodide 26 with boronate ester 27 subsequently provided
m,m-(CN) ZnH P (10), which was metallated with
2
4
ZnCuP (20).
2
Again for electronic reasons, tf (CN) Cu P (17), tf (CN) -
4
2
2
4
CuH P (19), and tf (CN) H P (21) could not be prepared
2
2
4
4 2
4
2 2
by the route described above. Demetallation of tf (CN)4-
Cu(OAc) to yield m,m-(CN) ZnCuP (12). Demetallation
2
4
2
II
Zn2P (16) afforded 21, which was remetallated with
2
of boronate 27 gave 28, which was remetallated with Cu
to provide monoporphyrin 29, and cross-coupling between
Cu(OAc) to afford a mixture of tf (CN) Cu P (17) and tf
2
4
2 2
(
CN) CuH P (19). The mixture of 17 and 19 was insepa-
2
1
6 and 29 afforded m,m-(CN) CuH P (11). Alternatively,
4 2 2
4
2 2
rable by chromatography methods; thus, separation was
eventually achieved by metallation of the mixture with
1 was also obtained by cross-coupling of iodide 30, ob-
II
tained by insertion of Cu into 26, and free-base boronate
8 (Scheme 3).
MgI to transform 19 into tf (CN) CuMgP (31). Gratify-
2
2
4
2
ingly, 17 and 31 now featured sufficiently different polarity
to allow chromatographic separation. Finally, demetallation
Synthesis of Triply Fused Diporphyrin Derivatives
[21]
with TFA afforded tf (CN) CuH P (19).
4
2 2
The oxidative conditions [Sc(OTf) , DDQ] introduced by
Osuka and coworkers were applied to the formation of tri- other sets of monoporphyrins [ZnP (1),
As control compounds for the electrochemical studies,
3
[
22]
(CN) ZnP
2
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4661

L. Echegoyen, F. Diederich et al.
FULL PAPER
Scheme 3. Synthesis of hybrid meso,meso-linked diporphyrins: (a) TFA; CH
2
Cl
2
; 20 °C; 2 h; 90%; (b) Cs
2 3 3 4
CO ; [Pd(PPh ) ]; PhMe; 80 °C;
3
h; 45%; (c) Cu(OAc) ; MeOH/CHCl , 1:1; ∆; 2 h; 92%; (d) Cs CO ; [Pd(PPh ) ]; PhMe/DMF, 2:1; 80 °C; 3 h; 75% (from 29); 99%
2 3 2 3 3 4
(from 28). Ar = 3,5-bis(tert-butyl)phenyl; DMF = dimethylformamide.
[24]
(
2)[8a,23]], meso,meso-linked diporphyrins [m,m-Zn P (6),
ner” and “outer” β-protons in the triply fused diporphyrins
2
2
[5b,5d]
m,m-(CN) Zn P (7)
Zn P (14),
lowing literature protocols.
], and triply fused diporphyrins tf are shifted upfield. Simultaneously there is a dramatic
2
2 2
[
25]
[5b,5d]
tf (CN) Zn P (15),
were prepared fol- downfield shift of the inner NH resonances in triply fused
free-base derivative 21 (δ = 1.34 ppm) relative to the corre-
2
2
2
2 2
sponding resonance in meso,meso derivative 13 (δ =
–
2.27 ppm) and monoporphyrin 5 (δ = –2.67 ppm). We take
1H NMR Spectroscopy
this as an indication that aromaticity, as measured by ring-
current effects, is reduced in triply fused porphyrins relative
to that in monoporphyrins. On the other hand, the explana-
tion might not be that straightforward because the inner
NH resonances in both the meso,meso- and triply fused
monozinc(II) derivatives appear at similar chemical shift
All new mono- and diporphyrins were fully characterized
as colored, high-melting stable solids. In the high-resolution
matrix-assisted laser-desorption-ionization mass spectra
(HR-MALDI-MS), the molecular ions appear as base
peaks with little or no fragmentation seen. Representative
[–2.14 (for 10) and –2.18 ppm (for 18)]. Overall, the ob-
1
H NMR spectroscopic data (CDCl ) for a selected series
3
served trends in chemical shift changes agree well with
those reported by Osuka and coworkers.
of compounds are depicted in Figure 2.
[
15c]
The β-protons of monoporphyrins 3 and 5 and the
“
outer” β-protons of the meso,meso-linked diporphyrins
b
c
d
(H , H , and H in 8, 10, and 13) appear at similar chemical
UV/Vis Spectroscopy
shifts between 8.56 and 9.13 ppm. In contrast, the “inner”
β-protons H of the meso,meso derivatives are shifted up-
a
The electronic absorption spectroscopic data in CHCl3
field into the range of 7.98 to 8.15 ppm, which is readily at 293 K are summarized in Table 1. Spectral comparisons
explained by the shielding from the neighboring orthogonal between differentially metallated mono- and diporphyrins
porphyrin moiety. In contrast, the resonances of both “in- are shown in Figure 3.
4662
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
of 2 and 4 peripheral CN groups, respectively, thereby re-
minding the spectral features seen in the corresponding
series of monoporphyrins, this is not the case for the sec-
ond, lower-energy Soret band.
The higher-energy Soret band of the triply fused dipor-
phyrins appears at wavelengths similar to those measured
for the meso,meso-linked derivatives. In contrast, the lower-
energy Soret band encounters a larger bathochromic shift
(Figure 3, bottom; Table 1). No characteristic changes in
absorption as a result of the introduction of peripheral CN
groups are observed. The most prominent feature in the
spectra of the triply fused diporphyrins is the very large
bathochromic shift of the three to four observed Q-bands,
with the end absorption appearing in the near infrared
[
1e,2a,3e]
around 1200 nm.
This shift is a direct result of the
greatly extended π-electron delocalization in the triply fused
diporphyrins relative to that in monoporphyrins and meso,-
meso-linked diporphyrins.
Electrochemistry
Significant information about the interaction between
two different metal-ion sites in meso,meso- and triply fused
diporphyrins was provided in a comprehensive electrochem-
ical investigation. The redox properties of the mono- and
diporphyrins were analyzed by cyclic voltammetry (CV)
and differential pulse voltammetry (DPV) in CH Cl2
2
(
+0.1  nBu NPF ). All potentials are reported relative to
4 6
Scheme 4. Synthesis of triply fused diporphyrins: (a) Sc(OTf)
DDQ; PhMe; ∆; 3 h; 85%; (b) Sc(OTf) ; DDQ; PhMe; ∆; 1 h; 90%
; MeOH/CHCl , 1:1; ∆; 2 h; quant.;
d) conc. HCl/MeOH, 1:1; 10 min; 20 °C; quant.; (e) Cu(OAc)
3
;
+
the ferrocene/ferricinium (Fc/Fc ) couple used as internal
reference. The data are summarized in Table 2.
3
(
(
16); 20% (18); (c) Cu(OAc)
2
3
2
;
Monoporphyrins generally exhibit similar electrochemi-
MeOH/CHCl
3
, 1:1; 20 °C; 2 h; inseparable mixture of 17 and 19; cal properties, capable of being stepwise oxidized or re-
Cl ; 30 min; 20 °C; 78% (pure 17); 17% (pure
1) (over 2 steps); (g) TFA; CHCl ; 14 h; 20 °C; quant. Tf =
CF SO , DDQ = 2,3-dichloro-5,6-dicyano-p-benzoquinone, DIEA
diisopropylethylamine, Ar = 3,5-bis(tert-butyl)phenyl.
(
3
f) MgI
2
; DIEA; CH
2
2
duced by two electrons to give π-cation radicals and dicat-
3
[
29a]
ions or π-anion radicals and dianions, respectively.
Early
3
2
electrochemical studies demonstrated that most of the por-
phyrins exhibited a reasonably constant potential difference
between the first and the second macrocycle-centered oxi-
dations or between the first and second macrocycle-cen-
tered reductions, as well as a similar HOMO–LUMO gap
=
[
26b]
of 2.25Ϯ0.15 V.
In the series of monoporphyrins, the maximum of the gram constructed from the electrochemical data revealed
Soret band shifts slightly to higher energy upon moving destabilization of the HOMO level and stabilization of the
The HOMO–LUMO energy level dia-
II
II
[30]
from the Zn , to the free-base, and to the Cu derivative LUMO level upon dimer formation.
Figure 3, top). The Q-bands show the expected character- When porphyrins with nonelectroactive centers (Zn, Cu)
istic splitting with two maxima for the Zn , four maxima are investigated, the redox processes involve the π-system
(
II
II
[15c]
for the free-base, and two weaker maxima for the Cu de- only.
When the two rings are sufficiently apart and not
With increasing number of peripheral CN conjugated, the dimer nearly behaves as two independent
groups, the Soret band shifts bathochromically (1Ǟ2Ǟ3, monomers. A two-electron oxidation process formally gives
Table 1). rise to a π-cation diradical. When the two rings are very
[
26,27]
rivative.
The Soret bands of the meso,meso-linked diporphyrins close and/or conjugated, strong π–π interactions generate
are split and broadened due to exciton chirality coupling mixed valence behavior. In this situation, the first oxidation
[
5c,5d,12c,28]
The Q-bands display the fea- process splits into two one-electron steps.[31,15c]
(
Figure 3, middle).
tures expected from the spectra of the monoporphyrins,
with m,m-(CN) ZnH P (10) notably showing the four max- (meso,meso-linked and triply fused) give rise to a complex
The results demonstrate that the two series of dimers
4
2 2
ima at similar wavelengths to those recorded for the free- redox situation. All of the different possible redox pathways
base monoporphyrin. While the higher-energy Soret band for the diporphyrins are shown in Scheme 5, which was pre-
(
Table 1) displays a bathochromic shift upon introduction viously proposed by Collman and coworkers.[31]
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4663

L. Echegoyen, F. Diederich et al.
FULL PAPER
1
Figure 2. Selected H NMR (300 MHz) spectroscopic data of mono- and diporphyrins in CDCl
3
. Ar = 3,5-bis(tert-butyl)phenyl.
3
Table 1. UV/Vis spectra recorded in CHCl at 293 K.
Compounds
Soret bands[a]
Q-bands[a]
Monoporphyrins
ZnP
1
2
3
4
5
422 (204600)
422 (186300)
427 (114500)
423 (111200)
426 (117600)
549 (8200), 586 (2200)
549 (7600), 587 (1300)
550 (5400), 591 (1100)
542 (5700), 577 (1000)
(CN)
(CN)
(CN)
(CN)
2
4
4
4
ZnP
ZnP
CuP
H
2
P
519 (5400), 554 (2400), 593 (1800), 649 (1300)
meso,meso-Diporphyrins
Zn
2
P
2
2
4
4
4
4
4
4
6
418 (347900), 457 (290400)
424 (245700), 461 (240000)
430 (137000), 460 (182500)
419 (98600), 453 (107800)
423 (166500), 457 (160000)
421 (66000), 454 (63800)
422 (146500), 456 (155200)
421 (210500), 456 (230000)
559 (70800), 595 (9700)
565 (54300), 611 (1530)
556 (39400), 637 (2300)
551 (28500)
522 (24000), 556 (31400), 596 (11300), 653 (4500)
522 (9300), 548 (12500), 593 (3700), 652 (1400)
557 (37600), 638 (1300)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
Zn
Zn
Cu
ZnH
CuH
ZnCuP
2
P
P
2
7
2
2
8
9
10
11
12
13
2
P
2
P
P
2
2
2
2
2
H
4
P
2
527 (53700), 563 (16500), 596 (17500), 655 (8400)
Triply fused diporphyrins
Zn
2
P
2
2
4
4
4
4
4
4
14
15
16
17
18
19
20
21
419 (113000)
528 (101600), 1068 (22900)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
Zn
Zn
Cu
ZnH
CuH
ZnCuP
2
P
P
2
422 (136000), 460 (45700)
423 (79100) ,469 (29800)
416 (39700)
424 (72700), 478 (47900)
415 (58100)
418 (89100), 462 (36100)
416 (85300), 476 (39300)
565 (112200), 923 (17900), 1053 (30600)
568 (81600), 955 (11000), 1093 (17200)
562 (35700), 576 (36000), 669 (3100), 987 (8300)
570 (71300), 1066 (15200), 1124 (10800), 1158 (6300)
566 (59300), 712 (5500), 1015 (15200)
567 (76500), 911 (11600), 1038 (16100)
567 (94800), 705 (11100), 1045 (19300), 1079 (19700)
2
2
2
P
2
P
P
2
2
2
2
2
4 2
H P
[
a] λmax /nm [eV] (ε, –1 cm–1).
4664
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
Figure 3. UV/Vis spectra of differentially metallated monoporphyrins 3–5, meso,meso-diporphyrins 8–13, and triply fused porphyrins 16–
3
21 recorded in CHCl at 293 K.
Table 2. Electrochemical reduction and oxidation potentials (V) vs. Fc/Fc+ from differential pulse voltammograms of mono- and dipor-
2 2 4 6
phyrins in CH Cl (+ 0.1  nBu NPF ).
Compounds
Oxidation
Reduction
HOMO–LUMO
[
a]
gap
E
ox.1
E
ox.2
E
ox.3
E
ox.4
E
ox.5
E
red.1
E
red.2
E
red.3
E
red.4
Monoporphyrins
ZnP
1
0.31
0.41
0.47
0.68
0.69
0.59
0.69
0.75
0.95
0.90
–1.87
–1.66
–1.65
–1.62
–1.47
–2.26
–2.03
–1.98
–2.00
–1.81
2.18
2.07
2.12
2.30
2.16
(CN)
(CN)
(CN)
(CN)
2
4
4
4
ZnP
ZnP
CuP
2
3
4
5
–2.24
–2.34
2
H P
meso,meso-Diporphyrins
Zn
2
P
2
2
4
4
4
4
4
4
6
0.19
0.40
0.82
0.74
0.80
1.03
–1.86
–1.71
–1.68
–1.64
–1.62
–1.62
–1.96
–1.83
–1.80
–1.77
–1.82
–1.82
–2.28
–2.18
–2.09
2.05
2.11
2.11
2.28
2.06
2.25
2.13
2.18
0.40[
0.43
0.64
0.44
0.63
0.46
0.63
b]
0.49
0.53
0.79
0.67
0.77
0.66
0.77
[b]
[b]
0.80
[b]
1.12
–2.37
–2.31
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
Zn
Zn
Cu
ZnH
CuH
ZnCuP
2
P
P
2
7
0.99 1.16[
b]
[b]
2
2
8
9
10
11
12
13
2
P
2
P
P
2
2
0.77
0.77
1.00
–2.06
–2.12
2
2
0.95
1.21
–1.67[
b]
–1.79
–1.66
[b]
2
4 2
H P
–1.55
Triply fused diporphyrins
Zn
2
P
2
2
4
4
4
4
4
4
14
15
16
17
18
19
20
21
0.03
0.01
0.13
0.40
0.25
0.40
0.22
0.43
0.25
0.38
0.33
0.73
0.52
0.74
0.49
0.83
0.75
0.89
0.86
1.16
0.99
1.34
0.94
1.03
1.08
–1.07
–1.07
–0.97
–0.83
–1.00
–0.83
–0.92
–0.76
–1.33
–1.26
–1.21
–1.08
–1.24
–1.08
–1.21
–1.03
–2.28
–2.17
–2.14
–2.02
–2.19
–2.04
–2.13
1.10
1.08
1.10
1.23
1.25
1.23
1.14
1.19
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
(CN)
Zn
Zn
Cu
ZnH
CuH
ZnCuP
2
P
P
2
2
2
2
P
2
P
P
2
2
2
2
2
4 2
H P
[a] Electrochemical HOMO–LUMO gap [eV]: ∆E = Eox.1 – Ered.1. [b] Poorly defined potentials.
Although mechanistic details have been previously re- (Zn, Cu, 2 H), either covalently linked by two amide bridges
ported, these were concerned mainly with two families of or by a single polyaromatic bridge (“Pacman” family). Our
dimeric cofacial diporphyrins with non-electroactive centers studies of dimeric porphyrins include direct lateral connec-
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4665

L. Echegoyen, F. Diederich et al.
FULL PAPER
The meta-CN groups on the meso-phenyl rings exert a
pronounced σ-acceptor effect, leading to significant shifts
in the redox potentials. Upon changing from ZnP (1) to
(
CN) ZnP (2) and to (CN) ZnP (3), the first reduction po-
2 4
tential shifts anodically from –1.87 to –1.66 V and to
1.65 V, respectively. Correspondingly, oxidation becomes
–
more difficult in this sequence (+0.31Ǟ+0.41Ǟ+0.47 V).
The free-base porphyrin (CN) H P (5; –1.47 V) is more
4
2
II
readily reduced compared to the Zn (3; –1.65 V) and the
II
Cu (4; –1.62 V) derivatives. On the other hand, the first
II
oxidation of Zn porphyrin 3 (+0.47 V) is facilitated as
compared to the corresponding electron transfer from the
II
Cu (4; +0.68 V) or the free-base (5; +0.69 V) porphyrin.
These observations are in agreement with previously re-
[
9b,14c,15c,29c–29f]
ported data.
Electrochemical Behavior of meso,meso-Linked
Diporphyrins
Scheme 5. General redox pathway for the oxidation or reduction
of the diporphyrin rings.
The DPVs are shown in Figure 4b and the measured re-
dox potentials are listed in Table 2. As a general trend, the
tion between two porphyrins arraying them in biaryl-type singly linked diporphyrins show similar behavior to that ex-
(
meso,meso) or planar (triply fused) orientation and guar- hibited by the two individual macrocycles connected in an
[
31]
anteeing maximum metal ion-metal ion interaction.
orthogonal, biaryl-type fashion. Three, and in some cases
even four 1e reductions, as well as four to five 1e oxidations
are observed, mirroring the doubling of the number of elec-
troactive chromophores as compared to the monoporphyr-
ins.
Electrochemical Behavior of Monoporphyrins
Redox potentials were found to be better defined in DPV
Similar to the monoporphyrin series, the exchange of the
experiments due to peak overlap and/or irreversibility ob- peripheral tert-butyl donor for CN acceptor groups shifts
served by CV. In the present discussion DPV results are the potentials anodically from –1.86 V (m,m-Zn P , 6) to
2
2
utilized, therefore the redox potentials do not necessarily –1.68 V [m,m-(CN) Zn P , 8] and from +0.19 V to +0.43 V,
4
2 2
correspond to E1/2 values. The DPVs of the monoporphyr- respectively.
ins are shown in Figure 4a. All derivatives feature two re- The bis(zinc) and bis(copper) derivatives m,m-
versible 1e oxidation steps and one reversible 1e reduction (CN) Zn P (8) and m,m-(CN) Cu P (9), as well as the hy-
4
2
2
4
2 2
II
wave. The second 1e reduction is irreversible for the Zn
brid systems m,m-(CN) ZnH P (10), m,m-(CN) CuH P
4 2 2 4 2 2
II
derivative, but reversible for the free-base and Cu porphy- (11), and m,m-(CN) ZnCuP (12) undergo the first two to
4
2
rins.
three reduction steps at very similar potentials (Table 2). In
Figure 4. a) DPVs of porphyrin monomers 1–5; b) meso,meso-linked diporphyrins 6–13; and c) triply fused diporphyrins 14–21.
666 Eur. J. Org. Chem. 2007, 4659–4673
4
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
comparison, the first two 1 e reduction steps of free-base as a result of the larger splitting between successive pro-
m,m-(CN) H P (13) are shifted anodically.
cesses (Figure 4c). In general within the limits of the poten-
4
4 2
The potential for the first 1e oxidations of the zinc deriv- tial window of the solvent (CH Cl ), two to three nicely
2
2
atives m,m-(CN) Zn P (8), m,m-(CN) ZnH P (10), and separated 1e reduction waves and two to four 1e oxidation
4
2
2
4
2 2
m,m-(CN) ZnCuP (12) vary only slightly (first: +0.43 to waves are observed by CV and DPV. We define the value of
4
2
+
0.46 V; third: +0.77 to +0.80 V; fourth: +0.95 to +1.00 V), the potential difference, ∆Eox = Eox(12) – Eox(11), where
with the exception of the second, which is facilitated for Zn2 Eox(11) and Eox(12) represent split potentials for the first oxi-
derivative 8 (+0.53 V) as compared to the hybrid systems 10 dation and ∆Ered = |Ered(12) – Ered(11)|, where Ered(12) and
(+0.67 V) and 12 (+0.66). In comparison, the first and sec- Ered(11) represent split potentials for the first reduction.
ond oxidation potentials of m,m-(CN) Cu P (9), m,m- Interestingly, the peak splitting values of the triply fused
4
2 2
(
CN) CuH P (11) and metal-free m,m-(CN) H P (13) are diporphyrins are strongly affected by the incorporation of
4 2 2 4 4 2
shifted anodically to 0.64 and 0.79 V (9) and 0.63 and 0.77 V the CN groups. Thus ∆Eox (CV) increases from 200 (no
11, 13), respectively, near the region of the second and third CN, 21) to 380 mV (2 CN, 23), then decreases again to
oxidation potentials of the zinc derivatives 8, 10, and 12. 200 mV (4 CN, 16). The ∆Ered values are 260 (21), 190 (23),
(
II
Accordingly, the fact that Zn monoporphyrin 3 is much and 240 mV (16). The dependence of the splitting on the
II
easier to oxidize than Cu monoporphyrin 4 and free-base attached cyano groups may be ascribed to the different dis-
[
33]
analog 5, is consistent with the relative anodic shift of tribution of the molecular orbitals.
zinc(II)-containing meso,meso-linked diporphyrins 8, 10, The split of the first oxidation and reduction processes
and 12 as opposed to the corresponding zinc-free 9, 11, and of the meso,meso-linked (CN) diporphyrins are almost the
4
1
3. Also, this may explain the facilitated second oxidation same, in the range of 0.10–0.23 V (Figure 4b). These values
of the bis(zinc) derivative 8 with respect to monozinc dipor- indicate some degree of electronic interaction between the
phyrins 10 and 12. two porphyrins. The triply fused (CN) diporphyrins exhibit
4
The fact that free-base derivative 5 is much easier to re- much larger differences, in the range 0.20–0.40 V and 0.24–
duce than metallated 3 and 4, is consistent with the easier 0.29 V (Figure 4c), respectively, between the oxidation and
reduction of the free-base derivative m,m-(CN) H P (13).
reduction processes. This behavior is further evidence of the
4
4 2
One issue to consider is whether a metal-centered redox stronger interaction between the two porphyrin rings in the
process occurs in the CuII porphyrin systems. There are triply fused than in the meso,meso-linked diporphyrins.
only a few publications reporting the electrochemistry of
The electrochemical HOMO–LUMO gaps reveal another
copper porphyrins, which are mainly concerned with the important difference between monoporphyrins and the two
electrochemical processes of the porphyrin ring.[ More- series of linked dimers.
32]
[5b–5d]
Whereas the electrochemical
over, these reports are not consistent. Kadish et al. and Ar- gap in (CN) ZnP (3) is 2.12 eV and is not lowered much
4
II
nold et al. suggested that Cu porphyrin derivatives un- upon changing to m,m-(CN) Zn P (8; 2.11 eV), it is low-
4
2 2
dergo only porphyrin ring-centered electrode reac- ered to 1.10 eV in tf (CN) Zn P (16). The lowered gap in
4
2 2
[
32a,32b]
tions.
However, other electrochemical studies provide triply fused 16 as compared to singly bridged 8 is a result
II
I
II
evidence for redox reactions of the Cu /Cu couple of Cu
of both a large anodic shift of the first reduction potential
By comparing the electro- (710 mV) and a substantial cathodic shift of the first oxi-
chemical behavior of m,m-(CN) ZnCuP (12) and tf(CN) - dation potential (300 mV). Similarly large reductions of the
porphyrin derivatives.[
32c,32d]
4
2
4
ZnCuP (20) with that of monomer (CN) CuP (4) it can be electrochemical gap can be calculated by comparing the
2
4
concluded that none of the redox waves observed are Cu DPV data (Table 2) of other related meso,meso-linked and
centered. triply fused systems. The low electrochemical gaps are a di-
Electronic coupling between the two porphyrin rings in rect result of the more extensive π-conjugation in the planar
the singly linked dimers is also apparent from the peak triply fused dimers.
splitting of the (partially overlapping) reduction and oxi-
Introducing two peripheral CN groups into the triply
dation waves, i.e. the first and second electron transfers, fused systems hardly affects the first reduction and oxi-
which are centered on the two porphyrin rings, occur at dation potentials as observed in the CV comparison be-
different potentials. However, the CVs and DPVs of the tri- tween arylated 14 (–1.07; +0.03) and dicyano derivative 15
ply fused dimers show a much more pronounced splitting (–1.07; +0.01). Upon introduction of two additional CN
due to the enhanced electronic coupling resulting from groups in 16, however, substantial potential shifts are ob-
the full delocalization over the two porphyrin served, when compared to the dicyano derivative 15. The
[
5c,5d,14a,15c,16]
nuclei.
reduction becomes facilitated by 90 mV (–0.97 V) and the
oxidation becomes more difficult by 130 mV (+0.13 V).
Trends similar to those observed for the meso,meso-
linked series become apparent when observing the influence
of the metal ion centers. The values for the first and second
oxidation potentials for the bis(copper) derivative m,m-
Electrochemical Behavior of Triply Bridged Diporphyrins
In contrast to the rather poorly defined, overlapping re- (CN) Cu P (9) are shifted anodically by 10 and 20 mV,
4
2 2
dox waves of the singly linked dimers, the redox waves of respectively, as compared to the other zinc free diporphy-
the triply fused systems are perfectly defined and reversible, rins 11 and 13. There is a small anodic shift for tf (CN)4-
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4667

L. Echegoyen, F. Diederich et al.
FULL PAPER
Cu2P2 (17) and tf (CN) CuH P (19, both +0.40 V) of dimers exhibit an obvious overlap of one-electron steps for
4
2 2
3
0 mV when compared to tf (CN) H P (21, +0.43 V) for both reduction and oxidation. In all systems, the introduc-
4 4 2
the first oxidation potential. There is also a similar shift for tion of peripheral CN groups shifts the redox potentials,
tf (CN) Cu P (17, +0.73 V) of 10 mV when compared to facilitating reduction and rendering oxidation more difficult.
4
2 2
tf (CN) CuH P (19, +0.74) for the second oxidation poten-
Changing the metal ions proved to have a crucial influ-
4
2 2
tial. However, there is a larger anodic shift of 90 mV for the ence on the redox potentials and the electrochemical gaps
second 1e oxidation process when comparing the copper of all porphyrins investigated. In the monoporphyrin series,
II
free-base hybrid 19 (+0.74 V) to metal-free 21 (+0.83 V).
the Cu derivative 5 has the largest gap (2.30 eV), whereas
II
Significantly lower first and second oxidation potentials the gaps in the Zn (1) and the free-base derivative (4) are
are found for the zinc containing series tf (CN) Zn P (16), reduced to 2.12 and 2.16 eV, respectively. This gap re-
4
2 2
tf (CN) ZnH P (18) and tf (CN) ZnCuP (20), reflecting duction mainly results from a greater ease of oxidation of
4
2
2
4
2
II
the easier oxidation of zinc porphyrins already observed in the Zn and a facilitated reduction of the free-base porphy-
the monoporphyrin and the meso,meso-linked diporphyrin rin. This is also observed for the meso,meso-linked (CN)4
series. As before there is a small anodic shift of 30 mV each systems, where the mixed-zinc/free-base diporphyrin 10 has
for the first and second oxidation potential when compar- the lowest gap (2.06 eV). Bis(copper) derivative 9 has the
ing tf (CN) ZnCuP (20) with the copper-free tf largest gap of the series (2.28 eV), with Cu monoporphyrin
4
2
(
CN) ZnH P (18). The same trend of a slightly facilitated 4 being both relatively difficult to oxidize and to reduce.
4 2 2
oxidation of copper porphyrins compared to the free-base, The actual decrease in the gaps for the meso,meso-(CN)4
is observed for 18 with respect to tf (CN) Zn P (16). series is as follows: ZnH (2.06 eV)ϽZn (2.11 eV)ϽZnCu
4
2
2
2
2
The reduction potentials of triply fused diporphyrins also (2.13 eV)ϽH (2.18 eV)ϽCuH (2.25 eV)ϽCu (2.28 eV)
4
2
2
show similar tendencies, when compared to the meso,meso- reflecting the above-mentioned effects.
linked diporphyrins. The first and second reduction poten- Notably, the effects of the metal ions on reduction poten-
tials of tf (CN) Cu P (17) and tf (CN) CuH P (19) are tials and the electrochemical gaps of the triply fused dipor-
4
2
2
4
2 2
equal. There is an anodic shift of 70 and 50 mV, respec- phyrins differ strongly from those seen in the monoporphy-
tively, for the first and the second reduction potential when rins and meso,meso-linked diporphyrins. In the triply fused
1
2
compared to the metal-free tf (CN) H P (21). Zinc-con- (CN) M M P series, the order for the electrochemical gap
4
4
2
4
2
taining diporphyrins 16, 18, and 20 show a much more diffi- is Zn (1.10 eV)ϽZnCu (1.14 eV)ϽH (1.19 eV)ϽCuH ,
2
4
2
cult reduction, with tf (CN) ZnH P (18) being the hardest Cu (1.23 eV)ϽZnH (1.25 eV). The Zn diporphyrin pos-
4
2
2
2
2
2
to reduce.
sesses the smallest gap due to the easiest oxidation in the
triply fused series. There is a substantial decrease of the first
reduction potential of CuH and Cu compounds, which is
2
2
not observed in the meso,meso series. This makes up for
their more difficult oxidation compared to zinc containing
Conclusions
A novel series of biaryl-type meso,meso-linked and diporphyrins. ZnH turned out to have the biggest gap of
2
planar triply fused diporphyrin arrays, featuring different the series. Unlike the meso,meso series, there seems to be no
numbers of CN groups attached to peripheral meso-aryl ease of reduction resulting from the free-base macrocycle;
II
II
groups and bound to different metal ions (Cu , Zn ), were in fact, this dimer exhibits the highest first reduction poten-
prepared and their electronic properties investigated by UV/ tial of the triply fused series. It is important to emphasize
Vis spectroscopy and electrochemistry. The corresponding that the influence of metal ions in the triply fused systems
monoporphyrins were also studied as controls. Electronic cannot be explained on the basis of the redox properties of
communication between the two macrocycles is obviously the corresponding monoporphyrins!
strongest in the triply fused arrays with their extended π-
This systematic electrochemical study reveals that elec-
chromophores. Whereas the electrochemical HOMO– tronic coupling in porphyrin arrays can be tuned by chang-
LUMO gaps are essentially the same for the monoporphyr- ing the connection mode, central metal, and attaching
ins (2.07–2.18 eV) and the meso,meso-linked arrays (2.05– mode. This finding warrants a more extensive investigation
2.28 eV), the gaps in the triply fused systems are reduced of metal ion effects on the optical and electronic properties
drastically by ca. 1 eV to values between 1.08 and 1.25 eV. of triply fused oligoporphyrin arrays introduced by the
This reduction of the HOMO–LUMO gap is enhanced Osuka group, which clearly are among the most exceptional
upon a further increase in the number of fused porphyrin advanced materials reported in recent years. Also, an inves-
[
4]
moieties. The electrochemical behavior of the triply fused tigation of the interactions of differentially metallated olig-
porphyrin dimers is significantly different from that of their oporphyrin arrays with covalently linked fullerenes repre-
corresponding, singly linked porphyrin dimers. In contrast sents a worthwhile future endeavor, which will be pursued
with the typical poorly defined redox behavior of singly by the authors of this paper.
linked porphyrin dimers, the triply fused dimers display re-
versible redox behavior. Apparent redox splitting is ob-
served for triply fused porphyrin dimers, which arises as a
Experimental Section
consequence of the improved electronic coupling resulting Materials and General Methods: Chemicals were purchased from
from full delocalization. However, singly linked porphyrin Acros, Aldrich, and Fluka and used as received. THF was distilled
4668
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
from Na/benzophenone. Toluene (PhMe) was distilled from CaH
All porphyrin reactions were carried under an inert atmosphere by
2
.
from the analysis solution by a ceramic tip (Bioanalytical System
Inc.) served as the reference electrode. The silver hexafluorophos-
phate solution was replaced daily, because of the instability of Ag
. Compounds 1,[ 2,
22]
[23]
6,
were prepared according to lit-
erature reports. Column chromatography was carried out using
Fluka silica gel 60 (SiO ; 230–400 mesh, particle size 0.040–0.063)
or Fluka aluminium oxide (alumina; particle size 0.050–0.150, pH
[24]
+
applying a positive pressure of N
2
[
5b,5d]
[25]
[5b,5d]
[5b,5d]
7,
14, 15,
and 22
to photoreduction. The stability of the reference electrode was ex-
amined by recording the ferrocene oxidation potential in the sol-
vent studied as a function of time. The formal potential of the
ferrocene-ferricenium system was found to be stable for about 12 h.
The counter electrode was made from platinum mesh (0.25 mm).
The solution was deaerated for 20 min with Ar prior to the electro-
chemical measurements. All experiments were performed at room
temperature. All potentials obtained from the DPV were corrected
using the formula Emax = E1/2 + ∆E/2, where ∆E is the pulse ampli-
tude.
2
7.0Ϯ0.5). Melting points (M.p.) for all compounds except 9, 11,
13, 17, 19, and 21 were measured in open capillaries with a Büchi
Melting Point B540 apparatus and are uncorrected. Thermal analy-
sis was performed for compounds 9, 11, 13, 17, 19, and 21 as an
estimation of the exact melting points by differential scanning calo-
e
rimetry (DSC) with a DSC822 (Mettler Toledo, Greifensee, Swit-
zerland) equipped with an intracooler. Measurements were per-
formed under N and cooling, as well as at heating rates of 10 °C/
2
{
µ-[10,10Ј,20,20Ј-Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-di-
2
1
22
23 24
21Ј
cyanophenyl)-5,5Ј-biporphyrinato(4-)-κN ,κN ,κN ,κ :κN
κN ,κN ,κN ]}dizinc(II) [m,m-(CN) Zn P (8)]
4 2 2
,
min. The curves were not reversible, however there was no decom-
2
2Ј
23Ј
24Ј
1
position cognizable by H NMR and FT-MALDI. It is yet unclear
if the values indicated as M.p. are actually melting or decomposi-
tion temperatures. H NMR and C NMR spectra were measured
on Varian Gemini 300 MHz spectrometers. Chemical shifts are re-
Method A: A saturated solution of Zn(OAc)
2
in MeOH was added
to a solution of 10 (25 mg, 1.5ϫ10 mmol) in CHCl , and the
resulting mixture was heated to reflux for 3 h in the dark to yield
(26 mg, quant.) as a brown solid.
1
13
–2
3
4
ported in ppm downfield from SiMe using the solvent’s residual
7
signal as an internal reference. Infrared spectra (IR) were recorded
with a Perkin–Elmer FT1600 spectrometer or a Perkin–Elmer
Spectrum BX II. UV/Vis spectra were recorded with a Varian
CARY-5 or Varian CARY-500 spectrophotometer. The spectra
Method B: To a solution of 6 (100 mg, 1.1ϫ10–1 mmol) in CHCl
3
–
1
(30 mL) was added a solution of AgPF (60 mg, 2.4ϫ10 mmol)
6
in CH CN (3 mL), and the mixture heated to reflux for 3 h. More
3
–
1
were measured in CHCl
[
3
in a quartz cuvette of 1 cm length; λmax
AgPF (60 mg, 2.4ϫ10 mmol) was added and heating to reflux
6
nm] (ε [–1 cm ]); shoulders: sh. EI mass spectra were measured
–1
was continued for 18 h. The mixture was washed with water, the
at 70 eV with a Hitachi-Perkin–Elmer VG-TRIBRID spectrometer.
High-resolution (HR) FT-MALDI spectra (only the monoisotopic
peak is reported) were measured with an Ionspec Fourier Trans-
form instrument with 2,5-dihydroxybenzoic acid (DHB), 3-hy-
droxypicolinic acid (3-HPA) or trans-2-[3-(4-tert-butylphenyl)-2-
organic layer dried (Na SO ), and the solvent evaporated. The re-
2
4
sulting brown solid was dissolved in CHCl (20 mL) and treated
3
with a solution of Zn(OAc)2 (1 g, 5.5 mmol) in MeOH (20 mL).
After stirring at 20 °C for 2 h, the mixture was washed with water
and dried (Na SO ). Evaporation and flash chromatography (SiO ;
2
4
2
methylprop-2-enylidene]malononitrile (DCTB) in MeOH/H
matrix, and the compound in CH Cl (two layer technique).
2
O as
2 2
CH Cl /hexane, 4:1) afforded 7 (78 mg, 80%) as a brown solid.
M.p. Ͼ300 °C. H NMR (300 MHz, CDCl ): δ = 9.11 (d, J =
3
1
2
2
4
8
5
1
1
1
.5 Hz, 4 H), 8.83 (d, J = 0.7 Hz, 4 H), 8.79 (d, J = 5.1 Hz, 4 H),
.75 (d, J = 4.5 Hz, 4 H), 8.40 (t, J = 0.7 Hz, 2 H), 8.15 (d, J =
Electrochemistry: All electrochemical measurements were per-
formed in re-distilled CH Cl (degassed with Ar) with 0.1 
nBu NPF as the supporting electrolyte on a CHI 660 Electro-
chemical Workstation (CH Instruments Inc, Austin, Texas). The
supporting electrolyte, nBu NPF (Aldrich, 98%), was recrys-
tallized three times from ethanol and dried under vacuum for 24 h
prior to use. The compounds were also dried under vacuum for 2 h
prior to use. For all samples, except the ones mentioned below, a
platinum wire was employed as the counter electrode. A silver wire
was used as the reference. Ferrocene (Fc) was added as an internal
reference, and all potentials were referenced relative to the Fc/Fc+
couple. A glassy carbon electrode (CHI, 3 mm in diameter), pol-
ished with 0.3 µm aluminum paste and ultrasonicated in deionized
2
2
.1 Hz, 4 H), 8.08 (d, J = 1.8 Hz, 8 H), 7.73 (t, J = 1.8 Hz, 4 H),
4
6
13
3
.46 (s, 72 H) ppm. C NMR (75.41 MHz, CDCl ): δ = 167.99,
48.89, 132.68, 131.11, 130.40, 130.04, 129.03, 121.21, 116.70,
12.70, 35.05, 31.90 ppm. IR (neat): ν˜ = 2957 (m), 2923 (m), 2856
4
6
(
1
(
m), 2236 (w), 1722 (m), 1590 (m), 1516 (w), 1458 (m), 1426 (w),
392 (w), 1362 (m), 1334 (m), 1279 (s), 1226 (m), 1120 (m), 1068
s), 1009 (s), 951 (m), 934 (m), 883 (m), 822 (m), 790 (s), 732 (m),
–1
–1
–1
7
3
13 (m), 688 (m) cm . UV/Vis (CHCl ): λ (ε,  cm ) = 430
(
137000), 460 (182500), 556 (39400), 637 (2300) nm. HR-MALDI-
+
+
106 2
MS (DCTB mix): calcd. for C112H N12Zn [M] 1746.72; found
1746.72.
2 2
water and CH Cl bath, was used as the working electrode. Scan
{µ-[10,10Ј,20,20Ј-Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-di-
2
1
22
23 24
21Ј
rates for cyclic voltammetry (CV) and differential pulse voltamme-
try (DPV) were 100 and 4 mV/s, respectively. For DPV measure-
ments, the amplitude was 50 mV and the pulse width was 0.05 s.
For samples 9, 11, 13, 17, 19, and 21, voltammetric experiments
were performed using a potentiostat/galvanostat Model CHI660A
cyanophenyl)-5,5Ј-biporphyrinato(4–)-κN ,κN ,κN ,κ :κN
,
2
2Ј
23Ј
24Ј
κN ,κN ,κN ]}dicopper(II) [m,m-(CN)
4
Cu
(3 mL) and Cu(OAc)
MeOH (3 mL) was heated to reflux for 30 h. CHCl was added,
and the mixture was washed with water (3ϫ), dried with Na
and the solvent evaporated. Purification over a short column (SiO
CH Cl
2
P
2
(9)]: Diporphyrin
–
2
13 (18 mg, 1.1ϫ10 mmol) in CHCl
3
2
in
3
2
SO
4
,
;
(CH Instruments Electrochemical Workstation) with a three-elec-
2
trode cell placed in a Faraday cage. The working electrodes con-
sisted of a platinum disk (Bioanalytical Systems, Inc.) with a dia-
meter of 1.0 mm. The surface of the electrode was polished using
extra fine carborundum paper (Buehler) followed by 0.3 µm alu-
mina and 0.25 µm diamond polishing compound (Metadi II,
Buehler). Next, the electrode was sonicated in water in order to
remove the traces of alumina from the metal surface, washed with
2
2
/cyclohexane, 9:1) afforded 9 as a violet solid (20 mg,
quant.). M.p. 380 °C. IR (neat): ν˜ = 2923 (s), 2853 (s), 2360 (w),
2324 (w), 2237 (w), 2052 (w), 1981 (w), 1809 (w), 1682 (w), 1591
(m), 1538 (w), 1456 (m), 1393 (w), 1362 (m), 1338 (m), 1291 (m),
1248 (m), 1222 (w), 1209 (w), 1074 (m), 1001 (s), 950 (m), 930 (m),
–
1
882 (m), 824 (m), 796 (s), 761 (m), 714 (s), 688 (m), 630 (w) cm .
–
1
–1
UV/Vis (CHCl
3
): λ (ε,  cm ) = 419 (98600), 453 (107800), 551
–
3
water, and dried. A silver wire immersed in 0.01 moldm silver
n m ( 2 8 5 0 0 ) . H R - M A L D I - M S ( 3 - H PA ) : c a l c d . f o r
nitrate and 0.09 moldm–3 (nBu)
NPF
in acetonitrile and separated
C
112
H106Cu
12 [M] 1744.73; found 1744.72.
+
+
4
6
2
N
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4669

L. Echegoyen, F. Diederich et al.
FULL PAPER
[
10,10Ј,20,20Ј-Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-dicya-
{µ-[Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-dicyanophenyl)-
2
1
22
23 24
21
22
23 24
21Ј
nophenyl)-5,5Ј-biporphyrinato(2–)-κN ,κN ,κN ,κ ]zinc(II)
[
and 27 (28 mg, 2.8ϫ10 mmol), together with Cs
4
10,10Ј,20,20Ј-5,5Ј-biporphyrinato(4-)-κN ,κN ,κN ,κ :κN
,
–
2
22Ј
23Ј
24Ј
m,m-(CN)
4
ZnH
2
P
2
(10)]: Compounds 26 (27 mg, 2.8ϫ10 mmol)
4 4 2
κN ,κN ,κN ]} [m,m-(CN) H P (13)]: Compound 8 (150 mg,
–
2
–2
2
CO
3
(14 mg,
8.6ϫ10 mmol) was dissolved in a 1:1 mixture of MeOH/conc.
.2ϫ10–2 mmol) and [Pd(PPh
)
4
] (4 mg, 3.2ϫ10 mmol) were dis-
–3
HCl and stirred briefly. After TLC confirmed completion of the
3
solved in a mixture of dry DMF (1.8 mL) and dry PhMe (3.5 mL).
The solution was deoxygenated via three freeze–pump–thaw cycles,
reaction, saturated aqueous NaHCO
the mixture was washed with 2  aqueous Na
water. The organic phases were dried with MgSO
evaporated to give 13 as a violet solid (139 mg, quant.). M.p. 358–
363 °C. H NMR (300 MHz, CDCl ): δ = 8.91 (d, J = 4.8 Hz, 4
3
H), 8.72 (d, J = 1.5 Hz, 4 H), 8.58 (d, J = 4.8 Hz, 4 H), 8.56 (d, J
= 4.8 Hz, 4 H), 8.31 (t, J = 1.5 Hz, 2 H), 7.98 (d, J = 4.8 Hz, 4 H),
3
and CH
2
Cl
CO
and the solvent
2
were added and
2
3
, followed by
and the resulting mixture was heated to 80 °C for 3 h under N
Water was added, and the mixture was extracted with CHCl . The
organic layer was dried (Na SO ), passed through a short column
SiO ), and the solvents evaporated. Chromatography (SiO
CH Cl /cyclohexane, 2:1) gave 10 as red solid. Yield 46%. M.p.
Ͼ300 °C. H NMR (300 MHz, CDCl
2
.
4
3
1
2
4
(
2
2
;
2
2
1
3
): δ = 9.14 (d, J = 4.5 Hz, 2 7.96 (d, J = 1.8 Hz, 8 H), 7.63 (t, J = 1.8 Hz, 4 H), 1.34 (s, 72 H),
1
3
H), 9.05 (d, J = 4.5 Hz, 2 H), 8.86 (d, J = 3.2 Hz, 4 H), 8.81 (d, J –2.27 (s, 4 H) ppm. C NMR (125.76 MHz, CDCl
3
): δ = 149.20,
=
4.5 Hz, 2 H), 8.79 (d, J = 4.5 Hz, 2 H), 8.72 (d, J = 4.5 Hz, 2 146.00, 140.67, 140.54, 134.64, 130.01, 123.63, 121.61, 118.80,
H), 8.67 (d, J = 4.5 Hz, 2 H), 8.43 (m, 2 H), 8.21 (d, J = 4.5 Hz, 2
H), 8.11 (s, 2 H), 8.08 (d, J = 4.5 Hz, 2 H), 7.76 (s, 4 H), 1.48 (s,
117.09, 114.22, 113.04, 35.22, 31.86 ppm. IR (neat): ν˜ = 3316 (w),
2957 (m), 2923 (s), 2853 (m), 2238 (w), 2051 (w), 1981 (w), 1812
7
1
1
1
1
2
2 H), –2.14 (s, 2 H) ppm. 13C NMR (75.41 MHz, CDCl
3
): δ = (w), 1683 (m), 1591 (m), 1560 (w), 1459 (m), 1428 (w), 1400 (w),
54.88, 151.14, 150.57, 148.85, 148.64, 146.28, 145.72, 141.10, 1362 (m), 1297 (w), 1259 (s), 1078 (w), 1016 (w), 980 (m), 965 (m),
40.41, 140.28, 140.17, 134.24, 133.39, 132.85, 130.35, 129.80, 930 (w), 914 (m), 882 (m), 799 (s), 735 (m), 715 (m), 686 (w), 641
29.65, 124.24, 123.30, 121.28, 121.08, 119.44, 116.96, 116.87, (w) cm . UV/Vis (CHCl
15.02, 113.84, 112.77, 112.56, 35.13, 31.79 ppm. IR (neat): ν˜ =
–
1
–1
–1
3
): λ (ε,  cm ) = 421 (210500), 456
(230000), 527 (53700), 563 (16500), 596 (17500), 655 (8400) nm.
+
+
110
960 (m), 2902 (m), 2342 (w), 2237 (w), 2099 (w), 1801 (w), 1684 HR-MALDI-MS (3-HPA): calcd. for C112H N12 [M] 1622.90;
(m), 1589 (m), 1525 (w), 1475 (m), 1425 (m), 1393 (m), 1361 (m), found 1622.90.
1
9
287 (m), 1259 (s), 1066 (s), 1000 (s), 978 (m), 951 (m), 933 (m),
{
µ-[5,5Ј,15,15Ј-Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-dicy-
–
1
14 (m), 899 (m), 881 (m), 800 (s), 713 (m), 687 (m), 668 (m) cm .
2
1
22
anophenyl)-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4-)-κN ,κN ,
): λ (ε, –1 cm ) = 423 (166500), 457 (160000), 522
–1
UV/Vis (CHCl
24000), 556 (31400), 596 (11300), 653 (4500) nm. HR-MALDI-
3
2
3
24
21Ј
22Ј
23Ј
24Ј
κN ,κ :κN ,κN ,κN ,κN ]}dizinc(II) [tf (CN)
Method A: Sc(OTf)
(174 mg, 3.5ϫ10–1 mmol) and DDQ (100 mg,
4.4ϫ10 mmol) were added under N to a solution of 8 (154 mg,
.6ϫ10 mmol) in dry PhMe (150 mL). The mixture was heated
to reflux at 140 °C for 30 min. After cooling to 25 °C, the mixture
was diluted with pyridine (5 mL), washed with H O (3ϫ100 mL)
and saturated aqueous NaCl (3ϫ100 mL), dried with Na SO , and
the solvent was evaporated in vacuo. Purification by repeated flash
chromatography (SiO ; CH Cl containing 1 % v/v Et N then
Al ; cyclohexane/CH Cl , 98:2 containing 1% v/v Et N), fol-
by dropwise addition of hex-
4 2 2
Zn P (16)]
(
+
+
MS (DCTB mix): calcd. for C112
684.81.
H
108
N
12Zn [M] 1684.81; found
3
–
1
1
2
–
2
8
[10,10Ј,20,20Ј-Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-dicya-
2
1
22
23 24
nophenyl)-5,5Ј-biporphyrinato(2–)-κN ,κN ,κN ,κ ]copper(II)
–
2
2
[m,m-(CN)
4 2 2
CuH P (11)]: Compounds 28 (16 mg, 1.6ϫ10 mmol)
–
2
2
4
and 26 (15 mg, 1.6 ϫ 10 mmol), together with Cs
2
CO
] (4 mg, 3.2ϫ10 mmol) were dis-
solved in a mixture dry DMF (1 mL) and dry PhMe (2 mL). After
purging with N for 2 h, the solution was heated to 80 °C for 5 h.
The mixture was diluted with chloroform, washed with water (3ϫ),
and dried with Na SO . After filtration through a plug (SiO ), the
solvent was evaporated and column chromatography (SiO
CH Cl /cyclohexane, 3:1) afforded 11 as a violet solid (20 mg, 75%)
3
(8 mg,
.4ϫ10–2 mmol) and [Pd(PPh
)
3 4
–3
2
2
2
2
3
2
O
3
2
2
3
2
lowed by precipitation from CHCl
ane, afforded 16 (154 mg, quant.).
3
2
4
2
;
Method B: Sc(OTf)
3
(400 mg. 8.1ϫ10–1 mmol) and DDQ (200 mg,
8.8ϫ10 mmol) were added under N to a solution of 24 (254 mg,
2
–
1
2
2
2
–
1
Alternatively, the coupling was also conducted with compounds 29
and 30 (yield: 99%). M.p. 367 °C. IR (neat): ν˜ = 3313 (w), 2924
2.9ϫ10 mmol) in dry PhMe (150 mL). The mixture was heated
to reflux at 140 °C for 30 min. After the workup (see above), 16
(
s), 2854 (m), 2237 (w), 2163 (w), 2051 (w), 1980 (w), 1654 (w),
(235 mg, 89%) was obtained as a dark blue powder. M.p. Ͼ300 °C.
H NMR (300 MHz, CDCl ): δ = 8.31 (d, J = 1.5 Hz, 4 H), 8.16
3
): λ (ε,  cm ) = (t, J = 1.5 Hz, 2 H), 7.76 (d, J = 4.7 Hz, 4 H), 7.65–7.64 (m, 12
H), 7.45 (d, J = 4.7 Hz, 4 H), 7.34 (s, 4 H); 1.46 (s, 72 H) ppm.
1
1
7
4
591 (m), 1560 (w), 1459 (m), 1363 (w), 1291 (w), 1008 (s), 796 (s),
–
1
–1
–1
61 (w), 714 (w), 689 (w) cm . UV/Vis (CHCl
21 (66000), 454 (63800), 522 (9300), 548 (12500), 593 (3700), 652
3
+
13
(
1400) nm. HR-MALDI-MS (3-HPA): calcd. for C112
H
108Cu N12
C NMR (75.41 MHz, CDCl
139.36, 139.13, 136.06, 132.29, 130.76, 129.38, 128.68, 128.17,
26.95, 121.11, 116.60, 113.05, 109.80, 35.01, 31.72 ppm. IR (neat):
ν˜ = 2960 (m), 2923 (m), 2236 (w), 1791 (w), 1722 (m), 1697 (m),
589 (m), 1477 (m), 1456 (m), 1423 (m), 1393 (m), 1379 (w), 1362
3
): δ = 154.14, 153.64, 151.32, 148.90,
+
[M] 1683.81; found 1683.81.
1
{
1
µ-[Tetrakis(3,5-di-tert-butylphenyl)-15,15Ј-bis(3,5-dicyanophenyl)-
2
1
22
23 24
21Ј
0,10Ј,20,20Ј-5,5Ј-biporphyrinato(4–)-κN ,κN ,κN ,κ :κN
,
1
22Ј
23Ј
24Ј
κN ,κN ,κN ]}-zinc(II)copper(II) [m,m-(CN)
saturated solution of Cu(OAc) in MeOH was added to a solution
of 10 (30 mg, 1.8ϫ10– mmol) in CHCl
, and the resulting mixture
was heated to reflux for 3 h in the dark to yield 12 (31 mg, quant.)
as a red-yellow solid. M.p. Ͼ300 C. IR (neat): ν˜ = 2958 (m), 2925
4 2
ZnCuP (12)]: A
(
(
w), 1343 (m), 1258 (s), 1200 (m), 1042 (s), 1018 (s), 951 (m), 942
m), 898 (m), 880 (m), 790 (s), 739 (w), 714 (m), 687 (m), 667 (w)
2
2
3
–
1
cm . UV/Vis: 423 (79100), 469 (29800), 568 (81600), 955 (11000),
1
C
093 (17200) nm. HR-MALDI-MS (DCTB mix): calcd. for
H N12Zn [M] 1742.69; found 1742.69.
112 102 2
+
+
(
m), 2865 (m), 2324 (w), 2237 (w), 1727 (w), 1685 (s), 1591 (m),
1
475 (m), 1458 (m), 1426 (m), 1406 (m), 1384 (s), 1362 (m), 1334 {µ-[Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-dicyanophenyl)-
2
1
22
(m), 1283 (m), 1248 (m), 1208 (m), 1087 (m), 997 (s), 949 (m), 928 5,5Ј,15,15Ј-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4-)-κN ,κN ,
2
3
24
21Ј
22Ј
23Ј
24Ј
(m), 900 (m), 883 (m), 824 (m), 792 (m), 725 (m), 714 (m), 687 (m), κN ,κ :κN ,κN ,κN ,κN ]}dicopper(II) [tf (CN)
4
Cu
): 422 (146500), 456 (155200), 557 17];{µ-[5,5Ј,15,15Ј-Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-di-
cyanophenyl)-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4-)-
2 2
P
–1
658 (m) cm . UV/Vis (CHCl
3
(37600), 638 (1300) nm. HR-MALDI-MS (DCTB mix): calcd. for
+
+
21
22
23 24
C
112
H
106CuN12Zn [M] 1745.73; found 1745.72.
4 2 2
κN ,κN ,κN ,κ ]}copper(II) [tf (CN) CuH P (19)]: A solution
4670
www.eurjoc.org © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
of 21 (40 mg, 2.5ϫ10–2 mmol) in CHCl
solution of Cu(OAc) in MeOH (10 mL) were heated to reflux for
h. More CHCl was added, and the mixture was washed
3ϫH O), dried (Na SO ), and the solvent was evaporated. Col-
umn chromatography (SiO ; CH Cl /cyclohexane, 9:1) gave 43 mg
of a mixture of 17 and 19. The mixture was dissolved in CH Cl
10 mL) and treated with DIEA. After being stirred at room tem-
perature for 30 min, it was diluted with CH Cl and washed
) and the organic layer was dried
) and the solvents evaporated. The residue was chromato-
Cl /cyclohexane, 3:1ǞCH Cl /EtOAc, 9:1)
(10 mL) and a saturated
added to a solution of 18 (15 mg, 8.9ϫ10–3 mmol) in CHCl
, and
3
3
2
the resulting mixture was heated to reflux for 3 h in the dark to
yield 20 (15 mg, quant.) as a gray solid. M.p. Ͼ300 °C. IR (neat):
ν˜ = 2943 (m), 2925 (m), 2855 (m), 2310 (w), 2237 (w), 1737 (w),
1694 (s), 1595 (m), 1480 (m), 1459 (m), 1426 (m), 1411 (m), 1387
(s), 1362 (m), 1334 (m), 1298 (m), 1250 (m), 1218 (m), 1054 (m),
990 (s), 935 (m), 912 (m), 900 (m), 883 (m), 824 (m), 801 (m), 725
3
(
3
2
2
4
2
2
2
2
2
(
–
1
2
2
(m), 714 (m), 687 (m), 660 (m) cm . UV/Vis (CHCl

3
): λ (ε,
cm ) = 418 (89100), 462 (36100), 567 (76500), 911 (11600),
1038 (16100) nm. HR-MALDI-MS (DCTB mix): calcd. for
–
1
–1
(
(
3ϫsaturated aqueous NaHCO
Na SO
graphed (alumina; CH
3
2
4
+
+
2
2
2
2
C
112
H
102CuN12Zn [M] 1741.69; found 1741.70.
to obtain 17 (34 mg, 78% yield) and 31 (7.3 mg, 17% yield) as
violet solids. Compound 31 was diluted in a solution of TFA
{
5
µ-[Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-dicyanophenyl)-
2
1
,5Ј,15,15Ј-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4–)-κN ,
(
0.1 mL) in CHCl
Subsequently, Et N (2 mL) was added dropwise, and the mixture
was diluted with CH Cl , washed (3ϫH O), the organic phase fil-
tered through a plug (SiO ), and the solvent evaporated to give 19
3
(10 mL) and was stirred overnight at 20 °C.
2
2
23 24
21Ј
22Ј
23Ј
24Ј
κN ,κN ,κ :κN ,κN ,κN ,κN ]} [tf (CN)
4
H
4
P
2
(21)]: A
solution of 16 (49 mg, 2.8ϫ10 mmol) in MeOH/conc. HCl, 1:1
was stirred for 30 min. Then saturated aqueous NaHCO and
CH Cl were added, and the mixture was washed with 2  aqueous
Na CO
MgSO
3
–
2
2
2
2
3
2
2
2
(7.2 mg, quant.) as a violet solid. Data for 17: M.p. 322 °C. IR
(neat): ν˜ = 2958 (s), 2925 (s), 2857 (s), 2237 (m), 2051 (w), 1981
(w), 1803 (w), 1676 (w), 1676 (w), 1591 (s), 1506 (m), 1459 (m),
2
3
, followed by water. The organic phases were dried with
4
and the solvent evaporated to give 21 as a violet solid
1
(
45 mg, quant.). M.p. 325 °C. H NMR (300 MHz, CDCl
3
): δ =
1425 (m), 1393 (m), 1348 (m), 1299 (m), 1258 (s), 1077 (s), 1009
8
2
.22 (d, J = 1.5 Hz, 4 H), 8.08 (t, J = 1.5 Hz, 2 H), 7.59–7.54 (m,
0 H), 7.28 (d, J = 4.8 Hz, 4 H), 1.37 (s, 72 H), 1.34 (s, 4 H)
(
6
s), 953 (m), 942 (m), 882 (m), 793 (s), 715 (m), 689 (m), 664 (w),
30 (m) cm . UV/Vis (CHCl ): λ (ε,  cm ) = 416 (39700), 562
3
–1
–1
–1
1
3
ppm. C NMR (125.76 MHz, CDCl
1
1
3
): δ = 149.55, 144.32, 139.51,
38.90, 134.64, 128.54, 126.43, 121.78, 117.98, 117.20, 116.79,
13.57, 35.18, 31.86 ppm. IR (neat): ν˜ = 3068 (w), 2953 (s), 2923
(
(
35700), 576 (36000), 669 (3100), 987 (8300) nm. HR-MALDI-MS
3-HPA): calcd. for C112H102Cu N12 [M] 1740.69; found 1740.69.
2
+
+
Data for 19: M.p. 345 °C. IR (neat): ν˜ = 3351 (w), 2955 (s), 2923
(
1
s), 2855 (m), 2237 (m), 1728 (w), 1590 (m), 1558 (w), 1458 (m),
414 (m), 1392 (w), 1361 (m), 1293 (w), 1247 (m), 1230 (m), 1176
(
(
s), 2853 (s), 2349 (w), 2238 (w), 2163 (w), 2051 (w), 1981 (w), 1661
m), 1632 (m), 1591 (m), 1523 (w), 1460 (m), 1426 (m), 1393 (m),
(
(
w), 1132 (w), 1079 (w), 1013 (w), 999 (w), 924 (m), 897 (w), 881
w), 818 (m), 793 (s), 752 (w), 723 (s), 686 (m), 644 (m), 623 (m)
1362 (m), 1290 (m), 1248 (m), 1222 (w), 1072 (m), 1010 (m), 954
(
w), 934 (w), 900 (w), 882 (w), 820 (m), 794 (m), 760 (w), 715 (m),
–
1
–1
–1
cm . UV/Vis (CHCl
5
MALDI-MS (3-HPA): calcd. for C112
found 1618.87.
3
): λ (ε,  cm ) = 416 (85300), 476 (39300),
–1
6
7
C
88 (w), 646 (w) cm . UV/Vis (CHCl
3
): 415 (58100), 566 (59300),
67 (94800), 705 (11100), 1045 (19300), 1079 (19700) nm. HR-
12 (5500), 1015 (15200). HR-MALDI-MS (3-HPA): calcd. for
+
+
106
H N12 [M] 1618.87;
+
+
112
H104CuN12 [M] 1679.78; found 1679.88.
[
5,5Ј,15,15Ј-Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-dicyano-
2
1
22
Supporting Information (see footnote on the first page of this arti-
cle): The synthesis and characterization of monoporphyrins 3–5,
building block 23, and precursors 24–30.
phenyl)-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4-)-κN ,κN
κN ,κ ]zinc(II) [tf (CN)
3
,
2
3
24
4
ZnH
2 2 3
P (18)]: Sc(OTf) (170 mg,
.4ϫ10–1 mmol) and DDQ (85 mg, 3.4ϫ10 mmol) were added
–1
to a solution of 10 (90 mg, 5ϫ10– mmol) in dry PhMe
2
under N
2
(
50 mL). The mixture was heated to reflux at 140 °C for 3 h. After
cooling to 25 °C, THF (25 mL) was added and stirring was contin-
ued for 1 h. The mixture was passed over a short column (Al
and the solvent removed. The residue was purified by chromatog-
raphy (SiO ; cyclohexane/CH Cl , 1:5) to yield 18 (15 mg, 15%) as
a dark purple solid. M.p. Ͼ300 °C. H NMR (300 MHz, CDCl
Acknowledgments
2
3
O )
We thank Dr. Carlo Thilgen for help with the nomenclature and
Fabien Choffat for the DSC measurements. This work was sup-
ported by the Swiss National Science Foundation (SNF), the
National Center of Competence in Research (NCCR) “Nanoscale
Science”, and the US National Science Foundation (NSF) CHE-
2
2
2
1
3
):
δ = 8.32–8.30 (m, 4 H), 8.18–8.16 (m, 2 H), 7.75 (d, J = 4.5 Hz, 2
H), 7.68 (d, J = 5.4 Hz, 2 H), 7.64–7.63 (m, 12 H), 7.44 (d, J =
5
0509989.
.4 Hz, 2 H), 7.37 (d, J = 4.5 Hz, 2 H), 7.34 (s, 4 H), 1.46 (s, 72
13
H), –2.18 (s, 2 H) ppm. C NMR (75.41 MHz, CDCl
3
): δ = 154.88,
1
1
1
1
51.14, 150.57, 148.85, 148.64, 146.28, 145.72, 141.10, 140.41, [1] a) A. Osuka, H. Shimidzu, Angew. Chem. 1997, 109, 93–94;
40.28, 140.17, 134.24, 133.39, 132.85, 130.35, 129.80, 129.65,
24.24, 123.30, 121.28, 121.08, 119.44, 116.96, 116.87, 115.02,
13.84, 112.77, 112.56 ppm. IR (neat): ν˜ = 2961 (m), 2238 (w), 1593
Angew. Chem. Int. Ed. Engl. 1997, 36, 135–136; b) A. Nakano,
T. Yamazaki, Y. Nishimura, I. Yamazaki, A. Osuka, Chem.
Eur. J. 2000, 6, 3254–3271; c) N. Aratani, A. Osuka, Y. H. Kim,
D. H. Jeong, D. Kim, Angew. Chem. 2000, 112, 1517–1521; An-
gew. Chem. Int. Ed. 2000, 39, 1458–1462; d) N. Aratani, A.
Osuka, Chem. Rec. 2003, 3, 225–234; e) D. Kim, A. Osuka,
Acc. Chem. Res. 2004, 37, 735–745; f) S. Hiroto, A. Osuka, J.
Org. Chem. 2005, 70, 4054–4058; g) N. Aratani, A. Takagi, Y.
Yanagawa, T. Matsumoto, T. Kawai, Z. S. Yoon, D. Kim, A.
Osuka, Chem. Eur. J. 2005, 11, 3389–3404; h) T. Ikeda, J. M.
Lintuluoto, N. Aratani, Z. S. Yoon, D. Kim, A. Osuka, Eur. J.
Org. Chem. 2006, 3193–3204.
(m), 1476 (s), 1393 (w), 1363 (m), 1345 (w), 1300 (m), 1266 (w),
1
9
(
247 (m), 1225 (w), 1199 (s), 1074 (w), 1023 (m), 1001 (m), 943 (s),
00 (m), 881 (m), 826 (m), 791 (s), 724 (m), 716 (m), 696 (m), 658
w) cm–1. UV/Vis (CHCl
): λ (ε,  cm ) = 424 (72700), 478
–1
–1
3
(47900), 570 (71300), 1066 (15200), 1124 (10800), 1158 (6300) nm.
+
+
HR-MALDI-MS (DCTB mix): calcd. for C112
108
H N12Zn [M]
1680.78; found 1680.78.
{
µ-[Tetrakis(3,5-di-tert-butylphenyl)-10,10Ј-bis(3,5-dicyanophenyl)-
[
2] a) A. Tsuda, A. Osuka, Science 2001, 293, 79–82; b) A. Tsuda,
2
1
22
5
,5Ј,15,15Ј-18,18Ј:20,20Ј-dicyclo-2,2Ј-biporphyrinato(4-)-κN ,κN ,
A. Osuka, Adv. Mater. 2002, 14, 75–79.
2
3
24
21Ј
22Ј
23Ј
24Ј
κN ,κ :κN ,κN ,κN ,κN ]}zinc(II)copper(II) [tf (CN)
4
-
[3] a) Y. H. Kim, D. H. Jeong, D. Kim, S. C. Jeoung, H. S. Cho,
ZnCuP (20)]: A saturated solution of Cu(OAc) in MeOH was
2
2
S. K. Kim, N. Aratani, A. Osuka, J. Am. Chem. Soc. 2001, 123,
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4671

L. Echegoyen, F. Diederich et al.
FULL PAPER
7
6–86; b) H. S. Cho, D. H. Jeong, S. Cho, D. Kim, Y. Matsu-
zaki, K. Tanaka, A. Tsuda, A. Osuka, J. Am. Chem. Soc. 2002,
24, 14642–14654; c) N. Aratani, A. Osuka, H. S. Cho, D. Kim,
2001, 123, 10304–10321; d) A. Tsuda, Y. Nakamura, A. Osuka,
Chem. Commun. 2003, 1096–1097.
1
[16] a) P. J. Chmielewski, Angew. Chem. 2004, 116, 5773–5776; An-
gew. Chem. Int. Ed. 2004, 43, 5655–5658; b) H. Segawa, D.
Machida, Y. Senshu, J. Nakazaki, K. Hirakawa, F. P. Wu,
Chem. Commun. 2002, 3032–3033; c) I. M. Blake, A. Krivok-
apic, M. Katterle, H. L. Anderson, Chem. Commun. 2002,
1662–1663; d) B. W. Jiang, S.-W. Yang, D. C. Brabini, W. E.
Jones Jr, Chem. Commun. 1998, 213–214.
17] a) J. Wytko, V. Berl, M. McLaughlin, R. R. Tykwinski, M.
Schreiber, F. Diederich, C. Boudon, J.-P. Gisselbrecht, M.
Gross, Helv. Chim. Acta 1998, 81, 1964–1977; b) C. Clausen,
D. T. Gryko, A. A. Yasseri, J. R. Diers, D. F. Bocian, W. G.
Kuhr, J. S. Lindsey, J. Org. Chem. 2000, 65, 7371–7378; c) J.
Seth, V. Palaniappan, R. W. Wagner, T. E. Johnson, J. S. Lind-
sey, D. F. Bocian, J. Am. Chem. Soc. 1996, 118, 11194–11207;
d) S. I. Yang, J. Seth, T. Balasubramanian, D. Kim, J. S. Lind-
sey, D. Holten, D. F. Bocian, J. Am. Chem. Soc. 1999, 121,
4008–4018; e) J.-P. Strachan, S. Gentemann, J. Seth, W. A.
Kalsbeck, J. S. Lindsey, D. Holten, D. F. Bocian, J. Am. Chem.
Soc. 1997, 119, 11191–11201.
J. Photochem. Photobiol. C 2002, 3, 25–52; d) H. S. Cho, H.
Rhee, J. K. Song, C. K. Min, M. Takase, N. Aratani, S. Cho,
A. Osuka, T. Joo, D. Kim, J. Am. Chem. Soc. 2003, 125, 5849–
5
8
860; e) D. Kim, A. Osuka, J. Phys. Chem. A 2003, 107, 8791–
816; f) Y. Nakamura, I.-W. Hwang, N. Aratani, T. K. Ahn,
D. M. Ko, A. Tagaki, T. Kawai, T. Matsumoto, D. Kim, A.
Osuka, J. Am. Chem. Soc. 2005, 127, 236–246.
[
[
4] F. Cheng, S. Zhang, A. Adronov, L. Echegoyen, F. Diederich,
Chem. Eur. J. 2006, 12, 6062–6070.
5] a) D. Bonifazi, F. Diederich, Chem. Commun. 2002, 2178–2179;
b) D. Bonifazi, M. Scholl, F. Y. Song, L. Echegoyen, G. Ac-
corsi, N. Armaroli, F. Diederich, Angew. Chem. 2003, 115,
[
5
116–5120; Angew. Chem. Int. Ed. 2003, 42, 4966–4970; c) N.
Armaroli, G. Accorsi, F. Song, A. Palkar, L. Echegoyen, D.
Bonifazi, F. Diederich, ChemPhysChem 2005, 6, 732–743; d)
D. Bonifazi, G. Accorsi, N. Armaroli, F. Song, A. Palkar, L.
Echegoyen, M. Scholl, P. Seiler, B. Jaun, F. Diederich, Helv.
Chim. Acta 2005, 88, 1839–1884.
[
6] a) T. Ikeue, K. Furakawa, H. Hata, N. Aratani, H. Shinokubo,
T. Kato, A. Osuka, Angew. Chem. 2005, 117, 7059–7061; An-
gew. Chem. Int. Ed. 2005, 44, 6899–6901; b) S. Shimizu, A.
Osuka, Eur. J. Inorg. Chem. 2006, 1319–1335.
[18] A. Malik, S. L. Reese, S. Morgan, J. S. Bradshaw, M. L. Lee,
Chromatographia 1997, 46, 79–84.
[19] T. Ogawa, Y. Nishmoto, N. Yoshida, N. Ono, A. Osuka, Angew.
Chem. 1999, 111, 140–142; Angew. Chem. Int. Ed. 1999, 38,
176–179.
[
7] a) J.-Y. Zheng, K. Tahiro, Y. Hirabayashi, K. Kinbara, K.
Saigo, T. Aida, S. Sakamoto, K. Yamaguchi, Angew. Chem.
2
[20] M. Kamo, A. Tsuda, Y. Nakamura, N. Aratani, K. Furukawa,
001, 113, 1909–1913; Angew. Chem. Int. Ed. 2001, 40, 1857–
861; b) D. Sun, F. S. Tham, C. A. Reed, L. Chaker, P. D. W. [21] W. J. Youngblood, D. T. Gryko, R. K. Lammi, D. F. Bocian, D.
T. Kato, A. Osuka, Org. Lett. 2003, 5, 2079–2082.
1
Boyd, J. Am. Chem. Soc. 2002, 124, 6604–6612; c) P. D. W.
Boyd, C. A. Reed, Acc. Chem. Res. 2005, 38, 235–242.
Holten, J. S. Lindsey, J. Org. Chem. 2002, 67, 2111–2117; M.
Speckbacher, L. Yu, J. S. Lindsey, Inorg. Chem. 2003, 42, 4322–
4337.
[
8] a) D. Bonifazi, H. Spillmann, A. Kiebele, M. de Wild, P. Seiler,
F. Cheng, T. Jung, F. Diederich, Angew. Chem. 2004, 116,
[22] T. X. Lu, J. R. Reimers, M. J. Crossley, N. S. Hush, J. Phys.
Chem. 1994, 98, 11878–11884.
4863–4867; Angew. Chem. Int. Ed. 2004, 43, 4759–4763; b) D.
Bonifazi, A. Kiebele, M. Stöhr, T. Jung, F. Cheng, F. Diederich,
H. Spillmann, Adv. Funct. Mater. 2007, online.
[23]
R. Cosmo, C. Kautz, K. Meerholz, J. Heinze, K. Mullen, An-
gew. Chem. 1989, 101, 638–640; Angew. Chem. Int. Ed. Engl.
1989, 28, 604–607.
[
[
[
[
9] a) A. Giraudeau, H.-J. Callot, J. Jordan, I. Ezhar, M. Gross, J.
Am. Chem. Soc. 1979, 101, 3857–3862; b) A. Giraudeau, L.
Ruhlmann, L. El Kahef, M. Gross, J. Am. Chem. Soc. 1996,
[24] A. Osuka, N. Tanabe, S. Nakajima, K. Maruyama, J. Chem.
Soc. Perkin Trans. 2 1996, 199–203.
118, 2969–2979.
[
25] N. Ono, H. Tomita, K. Maruyama, J. Chem. Soc. Perkin Trans.
1992, 2453–2456.
10] J. P. Collman, C. S. Bencosme, R. R. Durand Jr, R. P. Kreh,
F. C. Anson, J. Am. Chem. Soc. 1983, 105, 2699–2703; J. A.
Cowan, J. K. M. Sanders, J. Chem. Soc. Chem. Commun. 1985,
1
[
26] a) D. G. Davis in The Porphyrins (Ed.: D. Dolphin), Academic
Press, New York, 1978, vol. 5, pp. 127–152; b) R. H. Felton in
The Porphyrins (Ed.: D. Dolphin), Academic Press, New York,
1213–1214.
11] F. Li, S. Gentemann, W. A. Kalsbeck, J. Seth, J. S. Lindsey, D.
Holten, D. F. Bocian, J. Mater. Chem. 1997, 7, 1245–1262; P.
Hascoat, S. I. Yang, R. K. Lammi, J. Alley, D. F. Bocian, J. S.
Lindsey, D. Holten, Inorg. Chem. 1999, 38, 4849–4853.
12] a) A. Osuka, K. Maruyama, N. Mataga, T. Asahi, I. Yamazaki,
N. Tamai, J. Am. Chem. Soc. 1990, 112, 4958–4959; b) A.
Osuka, F. Kobayashi, K. Maruyama, N. Mataga, T. Asahi, T.
Okada, I. Yamazaki, Y. Nishimura, Chem. Phys. Lett. 1993,
1978, vol. 5, pp. 53–126.
[
27] a) G. D. Dorough, J. R. Miller, F. M. Huennekens, J. Am.
Chem. Soc. 1951, 73, 4315–4320; b) P. J. Spellane, M. Gouter-
man, A. Antpas, S. Kim, Y. C. Liu, Inorg. Chem. 1980, 19, 386–
391.
[28]
a) M. Kasha, Radiat. Res. 1963, 20, 55–70; b) M. Kasha, H. R.
Rawls, M. A. El-Bayoumi, Pure Appl. Chem. 1965, 11, 371–
392; c) H. L. Anderson, Chem. Commun. 1999, 2323–2330.
2
01, 223–228; c) H. S. Cho, D. H. Jeong, M.-C. Yoon, Y. H.
[29] a) K. M. Kadish, K. M. Smith, R. Guilard, E. Van Caemel-
Kim, Y.-R. Kim, D. Kim, S. C. Jeoung, S. K. Kim, N. Aratani,
becke, G. Royal, The Porphyrin Handbook, Academic Press,
Burlington, 1999, vol. 8, pp. 1–114; b) K. M. Kadish, E.
Van Caemelbecke, J. Solid State Electrochem. 2003, 7, 254–258;
c) K. M. Kadish, K. M. Smith, R. Guilard, The Porphyrin
Handbook, Academic Press, San Diego, 2000, vol. 9; d) L. A.
Bottomley, K. M. Kadish, Electrochemical and Spectrochemical
Studies of Biological Redox Components (Ed.: K. M. Kadish),
American Chemical Society, Washington DC, 1982; e) K. M.
Kadish, B. Boisselier-Cocolios, B. Simonet, D. Chang, H. Le-
don, P. Cocolios, Inorg. Chem. 1985, 24, 2148–2156; f) J. L.
Sessler, M. R. Johnson, S. E. Creager, J. C. Fettinger, J. A. Ib-
ers, J. Am. Chem. Soc. 1990, 112, 9310–9329; g) A. Giraudeau,
L. Ruhlmann, L. EI Kahef, M. Gross, J. Am. Chem. Soc. 1996,
118, 2969–2979.
H. Shinmori, A. Osuka, J. Phys. Chem. A 2001, 105, 4200–
4210.
[
13] D. P. Arnold, G. A. Heath, D. A. James, J. Porphyrins Phthalo-
cyanines 1999, 3, 5–31.
14] a) T. Ogawa, Y. Nishimoto, N. Yoshida, N. Ono, A. Osuka,
[
Angew. Chem. 1999, 111, 140–142; Angew. Chem. Int. Ed. 1999,
3
8, 176–179; b) S. Richeter, C. Jeandon, R. Ruppert, H. J. Cal-
lot, Chem. Commun. 2001, 91–92; c) S. Richeter, C. Jeandon,
J.-P. Gisselbrecht, R. Ruppert, H. J. Callot, J. Am. Chem. Soc.
2002, 124, 6168–6179.
[
15] a) A. Tsuda, A. Nakano, H. Furuta, H. Yamochi, A. Osuka,
Angew. Chem. 2000, 112, 572–575; Angew. Chem. Int. Ed. 2000,
39, 558–561; b) A. Tsuda, H. Furuta, A. Osuka, Angew. Chem.
2000, 112, 2649–2652; Angew. Chem. Int. Ed. 2000, 39, 2549–
2552; c) A. Tsuda, H. Furuta, A. Osuka, J. Am. Chem. Soc.
[30] R. Chitta, L. M. Rogers, A. Wanklyn, P. A. Karr, P. K. Kahol,
M. E. Zandler, F. DЈSouza, Inorg. Chem. 2004, 43, 6969–6978.
4672
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 4659–4673

meso,meso-Linked and Triply Fused Diporphyrins with Mixed Metal Ions
[
[
31] Y. Le Mest, M. LЈHer, N. H. Hendricks, K. Kim, J. P. Collman,
Inorg. Chem. 1992, 31, 835–847.
32] a) K. M. Kadish, N. Guo, E. V. Caemelbecke, R. Paolesse, D.
Monti, P. Tagliatesta, J. Porphyrins Phthalocyanines 1998, 2,
1966, 88, 1113–1116; f) K. M. Kadish, C. Araullo, G. B. Maiya,
D. Sazou, J.-M. Brabe, R. Guilard, Inorg. Chem. 1989, 28,
2528–2533.
[33] a) J. Wojaczynski, L. Latos-Grazynski, P. J. Chmielewski, P.
Van Calcar, A. L. Balch, Inorg. Chem. 1999, 38, 3040–3050; b)
S. Wolowiec, L. Latos-Grazynski, Inorg. Chem. 1994, 33, 3576–
3586.
4
39–450; b) D. P. Arnold, G. A. Heath, D. A. James, J. Porphy-
rins Phthalocyanines 1999, 3, 5–31; c) Q.-K. Zhuang, F. Scholz,
J. Porphyrins Phthalocyanines 2000, 4, 202–208; d) J. Lisowski,
M. Grzeszczuk, L. Latos-Grazynski, Inorg. Chim. Acta 1989,
Received: May 31, 2007
Published Online: August 21, 2007
1
61, 153–163; e) R. H. Felton, H. Linschitz, J. Am. Chem. Soc.
Eur. J. Org. Chem. 2007, 4659–4673
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4673