Synthesis, electrochemical, and photophysical studies of multicomponent systems based on porphyrin and ruthenium(II) polypyridine complexes

Article abstract of DOI:10.1016/j.tet.2007.06.074

Two ruthenium tris-bipyridine functionalized porphyrins 4, 8 and their Zn derivatives 4-Zn, 8-Zn were designed, synthesized, and characterized. The redox potentials of these complexes as well as their corresponding monomeric reference porphyrin and ruthen

Full text of DOI:10.1016/j.tet.2007.06.074

Tetrahedron 63 (2007) 9195–9205
Synthesis, electrochemical, and photophysical studies
of multicomponent systems based on porphyrin
and ruthenium(II) polypyridine complexes
a
b
a,b,
Xien Liu,a Jianhui Liu,a, Jingxi Pan, Samir Andersson and Licheng Sun
*
*
aState Key Laboratory of Fine Chemicals, Dalian University of Technology, Zhongshan Road 158-46, Dalian 116012, PR China
bSchool of Chemical Science and Engineering, Department of Chemistry,
Royal Institute of Technology (KTH), 10044 Stockholm, Sweden
Received 25 December 2006; revised 16 June 2007; accepted 19 June 2007
Available online 30 June 2007
Abstract—Two ruthenium tris-bipyridine functionalized porphyrins 4, 8 and their Zn derivatives 4–Zn, 8–Zn were designed, synthesized,
and characterized. The redox potentials of these complexes as well as their corresponding monomeric reference porphyrin and ruthenium
bipyridine complexes were also measured for comparison. Primary dynamic studies on the electron injection and backing recombination be-
tween these complexes and TiO2 nanoparticles were carried out by means of transient absorption spectroscopy. The results indicate that
a long-lived charge separation state was obtained in these assemblies.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
porphyrin complexes, with the reference compounds listed
in Figure 1.
Photoinduced electron transfer or energy transfer processes
in supramolecular species (molecular dyads, triads, and tet-
rads) consisting of metalloporphyrin and ruthenium polypyr-
idine complexes are currently the objective of extensive
investigations.1 Many of these have been based on the ex-
cited state chemistry of metalloporphyrin and ruthenium
polypyridine and on their favorable electrochemical, photo-
physical, and photochemical properties.2 The important rea-
sons for such investigations arise from the interest in
mimicking the structures and functions of photosynthesis,3
construction of the nanometer scale wires,4 switches,5 logic
gates,6 and other molecular devices.7 These functions may
be achieved by programming such assemblies through mol-
ecule design, so they can transfer energy or electron in one
particular direction. This is possible by using binuclear or
trinuclear complexes with different metals or by having dif-
ferent terminal ligand substituents. We have a particular
interest in the assembly of polychromophore systems,
especially those involving metalloporphyrin and ruthenium
polypyridine. Recently, we have shown that the intramole-
cular electron transfer from the higher excited state S2
of a zinc porphyrin to a covalently linked ruthenium com-
plex was possible.1e,f,8 Herein, we report the synthesis,
electrochemical properties, and photophysical behavior of
the bis- and tris-ruthenium tris(bipyridine)-substituted
2. Results and discussion
2.1. Synthesis
The basic skeleton of our target molecules is a porphyrin
connected ruthenium polypyridine complexes at its two or
three meso positions. The desired molecule 4 was synthe-
sized from the requisite precursor 1 of cis-A2B2 type. Por-
phyrin 1 was prepared according to the known procedure9
(Scheme 1) and was separated from the other porphyrin
products, which include bis(cis, trans)-, tris- and tetrakis-
nitrophenyl-substituted porphyrins. The tris(4-nitrophenyl)
porphyrin 5 was obtained in the same batch. The 12% yield
for both products should be considered good in giving the
two desired porphyrins 1 and 5 simultaneously. Except for
porphyrins 1 and 5, bis(trans) and tetrakis analogs were
not collected due mainly to their extremely low yields, al-
though analysis of this mixture by TLC indicated that these
isomers could be separated. SnCl2/HCl was used for the sub-
sequent aromatic nitro group reduction10 to afford the amino
derivative 2 in good yield. Hydrochloric acid can also pre-
vent the complexation of tin to free porphyrin. The following
amidation with 40-methyl-2,20-bipyridinyl-4-carbonyl chlo-
ride11 resulted in the formation of compound 3 in moderate
yield. In the following coordination step, 2 equiv of
* Corresponding authors. E-mail: liujh@dlut.edu.cn
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.06.074

9196
X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
COOEt
N
N
N
N
N
N
N
N
HOOC
N
Ru
N
COOEt
M
EtOOC
COOEt
Ru
PH2 , ZnP
COOEt
N
N
N
N
O
N
N
N
N
N
Ru
N
COOEt
M
N
H
EtOOC
COOEt
PH2Ru, ZnPRu
M = 2H, Zn
Figure 1. The structures of reference compounds studied.
cis-Ru(4,40-di-CO2Et-2,20-bpy)2Cl2 was needed for the
complete transformation12 to give the stable ruthenium(II)
coordination complex 4 in yield of 35%. Different reaction
conditions were examined to improve the yield without
any success. The possible reason is either the coordination
ability of bipyridine decreases remarkably by the existence
of the amide bond or the first ruthenium complex formed
will prevent the coordination of the second bipyridine with
ruthenium due to the charge repulsion of two Ru(II) ions. Fi-
nally, Zn(II) insertion was accomplished with Zn(OAc)2 in
chloroform with a little EtOH at room temperature to afford
the corresponding Zn(II) porphyrin complex 4–Zn in almost
quantitative yield. In a similar manner starting from porphy-
rin 5, we also obtained tris-meso-ruthenium tris(bipyridine)
porphyrin 8 as well as its Zn(II) complex 8–Zn (Scheme 2).
All of the compounds were insoluble in hexane or alcohols
but were very soluble in most other organic solvents, such
as acetonitrile or dichloromethane. Characterization of these
complexes has been made by 1H and 13C NMR, mass spec-
trometry, IR, UV–vis spectroscopy, and elemental analyses.
The 1H NMR spectrum of 4 is analyzed as a representative
example. It has signals that are consistent with the construc-
tion of the amide bond between the porphyrin and the ruthe-
nium tris(bipyridine) subunit at 9.56 ppm. The AA0XX0 spin
system of the phenyl protons was identified as a set of dd
split occurring between 7.8 and 8.4 ppm. As expected, the
b-pyrrolic and porphyrin aromatic protons are located fur-
ther downfield in the 8.8–9.0 ppm region. The internal NH
protons are shielded due to a ring current of the aromatic
macrocycle. Thus, the NH of porphyrin 4 containing the
ruthenium tris(bipyridine) subunit at the meso position
resonates at ꢀ2.82 ppm, comparable to that of the
corresponding smaller-sized substituents porphyrins 2 and
3, at ꢀ2.72 and ꢀ2.75 ppm, respectively. This indicates
that there was no obvious distortion of the planar macro-
cyclic structure and therefore a decrease of the ring current
effect. More importantly, no diastereoisomers have been
discovered through its 1H NMR due to restriction of free ro-
tation between the meso carbon and phenyl amide ruthenium
1
tris(bipyridine) subunit. Due to a significant overlap of H
NMR signals in the aromatic region, combined 1H–1H
COSY and TOCSY spectra were taken to assign the protons
in the porphyrin complex 4.
2.2. Electrochemistry
The redox potentials for 4–Zn, 8–Zn and reference com-
pounds Ru,13 ZnP,14 PH2Ru,1e and ZnPRu1e (their formu-
las are listed in Fig. 1) are summarized in Table 1. Reversible
electronic waves are observed for the redox processes of all
zinc complexes (negative potential range). In addition to the
irreversible oxidation peaks at E1/2¼1.65 (4–Zn) and 1.62 V

X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
9197
Ar
Ar
Ar
COCl
N
O
NH
N
N
NH
N
N
NH
N
N
N
SnCl2/HCl
N
N
N
H
Ar
NH2
Ar
NO2
Ar
CHCl3-HOAc
reflux, 12 h
CH2Cl2, reflux, 4 h
HN
HN
HN
60%
82%
O
HN
NH2
NO2
1
2
N
N
3
COOEt
Ar
N
N
N
N
O
NH
N
N
Ru
N
COOEt
N
H
Ar
N
HN
cis-Ru(4, 4'-di-CO2Et-2, 2'-bpy)2Cl2
Zn(OAc)2.2H2O
CHCl3-EtOH, rt, 12 h
98%
4-Zn
EtOOC
COOEt
HOAc, reflux, 1 h, 35%
O
HN
N
N
N
EtOOC
N
Ru
N
COOEt
Ar =
N
EtOOC
COOEt
4
Scheme 1. Synthesis of complex 4–Zn.
(8–Zn), the complexes 4–Zn and 8–Zn underwent three
reversible one-electron reductions and two one-electron
oxidations between ꢀ1.50 and 2.00 V (see Fig. 2). The
reduction for compound 4–Zn occurred at E1/2¼ꢀ0.76,
ꢀ1.04, and ꢀ1.45 V while for 8–Zn at E1/2¼ꢀ0.79,
ꢀ1.05, and ꢀ1.45 V. On the oxidation side, there are two
1, we summarized Table 2 according to the oxidation and re-
duction peaks’ order rather than the E1/2 values, because
these redox processes are mostly irreversible and very intri-
cate, especially at the oxidation side (see complex 4 in
Fig. 2). It is evident that the intensity of Ru2+/Ru3+ increases
with the number of Ru. Energy transfer is favored by the
free-base porphyrin. However, the corresponding zinc por-
phyrin readily underwent oxidative electron transfer.15
This was the principle reason for the differences observed
in redox properties between the free base and zinc com-
plexes.
reversible peaks: E1/2¼0.86 and 1.21 V for 4–Zn and E1/2
¼
0.80 and 1.19 V for 8–Zn. The irreversible peaks were
assigned to metal-based oxidation (Ru2+/Ru3+) couple, com-
pared to reference compound Ru. The irreversible waves
were caused by the introduction of carboxylic groups to
the bipyridyl ligands, resulting in different rates of the redox
reaction. The different ratio of Ru and porphyrin units was
also an important factor. The E1/2 values for redox processes
of the two zinc complexes are very similar. The different
waves could be easily assigned to their individual compo-
nents by comparison with the redox couples of the reference
compounds Ru and ZnP (see Table 1). These data suggested
that the first and second oxidations of the two compounds are
related to the ZnP part of the multicomponent while the third
oxidation to the Ru subunit. The reductions of them also oc-
curred via stepwise electrode processes involving the bipyr-
idyl ligands and ZnP parts of the multicomponents. On the
other hand, the Zn-free counterparts 4, 8 and their reference
compounds PH2,14 Ru, and PH2Ru1e (their formulas see
Fig. 1) are recorded in Table 2. Different from those in Table
2.3. Steady-state absorption spectra
The UV–vis absorption spectra of compounds 8 and 8–Zn
are shown in Figure 3a. The free-base complex 8 exhibited
six distinct absorption maxima in the visible region, and
the numerical data of the spectra are summarized in Table
3. Soret bands at around 420 nm (S0/S2 transition) and
Q-bands at 512, 551, 591, and 646 nm (S0/S1 transition)
were observed. UV–vis absorption spectra of the free base
8 in different concentrations are given in Figure 3b. They
show that the absorption increases with increasing concen-
tration of free base. In addition, the absorption for the
ester-attached [Ru(bpy)3]2+ moiety centered at around
475 nm (MLCT transition) is red shifted by 25 nm relative

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X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
N
N
NO2
NH2
NH
O
COCl
N
NH
N
N
NH
N
N
O
SnCl2/HCl
N
N
NH
N
N
NO2
Ar
NH2
N
Ar
CHCl3-HOAc
reflux, 12 h
CH2Cl2, reflux,
4 h, 62%
N
H
Ar
HN
HN
HN
84%
NO2
NH2
O
HN
5
6
N
N
7
EtOOC
COOEt
N
N
N
N
Ru
N
COOEt
N
COOEt
HN
O
COOEt
N
N
N
O
cis-Ru(4, 4'-di-COOEt-2, 2'-bpy)2Cl2
Zn(OAc)2.2H2O
NH
N
N
COOEt
8-Zn
N
Ru
N
H
HOAc, reflux, 1 h
35%
Ar
CHCl3-EtOH, rt, 12 h
98%
HN
N
N
EtOOC
COOEt
COOEt
O
HN
N
N
EtOOC
N
Ru
N
N
N
EtOOC
COOEt
8
Scheme 2. Synthesis of complex 8–Zn.
to that of the parent [Ru(bpy)3]2+. This effect is attributed to
the introduction of ester groups in the pyridine rings.16 Com-
pound 8–Zn shows two Q-bands due to the increased molec-
ular symmetry of D4h, which is a typical pattern of regular
metal porphyrins. The absorption spectra of 4 and 4–Zn
are omitted due to their similarity to that of 8 and 8–Zn.
The absorption maxima for these complexes are summarized
in Tables 3 and 4. Compared to its free base, the maximum
absorptions of the Soret band produced a bathochromic shift
(10 nm) because of the reduction of the electron density of
the porphyrin ring by the insertion of Zn(II). The maximum
absorption spectra of Q-bands appeared at 563 and 605 nm
as reported previously.1e
Table 1. Redox potentials of ZnP based complexes in CH2Cl2
Oxidation E1/2 (V vs SCE)
P/P+ P+/P2+ Re/Re+ Ru2+/Ru3+ L/Lꢀ
Reduction E1/2 (V vs SCE)
P/Pꢀ
ꢀ
L0/L0
2.4. Emission measurements
Ru
ZnP
1.66
ꢀ0.76
ꢀ1.02
Steady-state fluorescence measurement of 8 and 8–Zn were
performed subsequently. Figure 4a shows their fluorescence
emission spectra. At room temperature upon excitation of
8–Zn at 552 nm, the only detectable luminescence was
0.85 1.32
ꢀ1.31
ꢀ1.43
ꢀ1.45
ꢀ1.45
ZnPRu 0.78 1.17
4–Zn 0.86 1.21
8–Zn 0.80 1.19
1.68
1.65
1.62
ꢀ0.79
ꢀ0.76
ꢀ0.79
ꢀ1.07
ꢀ1.04
ꢀ1.05

X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
9199
ZnPRu
PH Ru
2
2
1
0.0
V vs SCE
-1
-2
2.0
1.0
0.0
V vs SCE
-1.0
-2.0
4
4-Zn
2
1
0
V vs SCE
-1
-2
2
1
0
V vs SCE
-1
-2
8-Zn
8
2
1
0
V vs SCE
-1
-2
2
1
0
V vs SCE
-1
-2
Figure 2. Cyclic voltammogram for complexes PH2Ru, 4, 8, ZnPRu, 4–Zn, and 8–Zn in 10ꢀ3 M CH2Cl2/0.1 M TBAPF6 on a glassy carbon disc electrode at
a scan rate of 50 mV/s and reported relative to SCE.
due to the porphyrins, in which the emission from zinc com-
pound was only 2% in intensity relative to that of free-base
complex 8. The very weak emission intensity observed for
zinc compounds indicated a strong quenching process,
which could be a result of electron transfer from the porphy-
rin singlet state to the ruthenium moiety. This process is fa-
vored by the presence of the heavy metal.17 On the other
hand, the observation of fluorescence only from porphyrins
but not from ruthenium moieties indicates that we could ex-
cite the zinc porphyrin unit in 8–Zn selectively, which is cru-
cial for investigating photoinduced electron and energy
transfer processes in multicomponent systems. Similarly, 4
and 4–Zn were faced with the same situation (data not
shown). The quantum yields of fluorescence are determined
as Ff 4–Zn¼0.00114 and Ff 8–Zn¼0.00065 for 4–Zn and
8–Zn, respectively. These values are significantly lower
than that of zinc tetraphenylporphyrin (Ff¼0.031). The nu-
merical data of the spectra are summarized in Tables 3 and 4.
Table 2. Redox potentials of Zn-free porphyrin based complexes in CH2Cl2
Oxidation
Reduction
Eox[1] Eox[2] Eox[3] Eox[4] Ered[1] Ered[2] Ered[3]
PH2
Ru
PH2Ru 1.12
4
8
0.62
0.93
ꢀ1.45
1.54
1.41
1.63
1.57
ꢀ0.94
ꢀ0.71
ꢀ0.66
1.41
1.35

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X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
2.0
(a)
(b)
10-6-10-1
2.0
1.5
1.0
0.5
0.0
8-Zn
8
1.5
1.0
0.5
0.0
8
400
500
Wavelength [nm]
600
700
400
500
Wavelength [nm]
600
700
Figure 3. (a) UV–vis absorption spectra of the free base 8 and 8–Zn in CH3CN [5ꢁ10ꢀ6]. (b) UV–vis absorption spectra of the free base 8 in different con-
centrations [10ꢀ6–10ꢀ1 M].
Table 3. Absorption and emission data of the free bases in acetonitrile solutions at 298 K [5ꢁ10ꢀ6 M]
Absorption lmax [nm] (3 [Mꢀ1 cmꢀ1])
Fluorescence lmax [nm] (rt)
B (0–0)
Qy (1–0)
Qy (0–0)
Qx (1–0)
Qx (0–0)
Q (0–0)
Q (0–1)
4
418 (1.16ꢁ106)
419 (1.86ꢁ106)
417 (2.01ꢁ106)
512 (7.55ꢁ104)
510 (1.31ꢁ105)
514 (6.78ꢁ105)
551 (4.24ꢁ104)
552 (5.85ꢁ104)
550 (5.22ꢁ104)
591 (1.49ꢁ104)
589 (5.20ꢁ103)
587 (1.65ꢁ103)
646 (1.63ꢁ104)
647 (5.70ꢁ103)
646 (1.85ꢁ103)
655
657
654
721
722
721
8
PH2Ru
Table 4. Absorption and emission data of the zinc complexes in MeCN solutions at 298 K [5ꢁ10ꢀ6 M]
Absorption lmax [nm] (3 [Mꢀ1 cmꢀ1])
Fluorescence lmax [nm](rt)
B (0–0)
Q (1–0)
Q (0–0)
Q (0–0)
Q (0–1)
4–Zn
8–Zn
ZnPRu
429 (1.15ꢁ106)
430 (2.12ꢁ106)
427 (2.41ꢁ106)
563 (4.14ꢁ104)
563 (8.76ꢁ104)
561 (1.14ꢁ105)
607 (2.69ꢁ104)
605 (5.70ꢁ104)
602 (7.60ꢁ104)
616
618
617
655
659
661
1.0
(a)
(b)
552nm
10
10-1-10-6
0.8
0.6
0.4
0.2
0.0
8
8
6
4
2
8
8-Zn
0
600
650
700
Wavelength [nm]
750
800
550
600
650 700
Wavelength [nm]
750
800
(c)
(d)
PH2Ru
8
0.05
0.04
0.03
0.02
0.01
0.00
ZnPRu
2.5
2.0
1.5
1.0
0.5
4
8-Zn
4-Zn
0.0
600
600
650
Wavelength [nm]
700
750
800
650
700
Wavelength [nm]
750
800
Figure 4. (a) Steady-state emission spectra of 8 and 8–Zn (lex¼552 nm) in CH3CN [5ꢁ10ꢀ6 M]. (b) Steady-state emission spectra of the free base 8 in different
concentrations [10ꢀ1–10ꢀ6 M]. (c) Steady-state emission spectra of 4–Zn, 8–Zn, and their reference ZnPRu (lex¼552 nm) in CH3CN [5ꢁ10ꢀ6 M]. (d) Steady-
state emission spectra of 4, 8, and their reference PH2Ru (lex¼552 nm) in CH3CN [5ꢁ10ꢀ6 M].

X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
9201
Figure 4b shows fluorescence emission spectra of the free
complex 8 in different concentrations. We could see that
its intensity decreased with increased concentration, which
indicated that the fluorescence quenching of free complex
8 by intermolecular electron transfer (or energy transfer) be-
came significant at high concentration. Figure 4c and d shows
fluorescence emission spectra of 4–Zn, 8–Zn, ZnPRu and
their free-base compounds, respectively, from which we
could see that the emission of their porphyrin parts is
quenched by introducing Ru units. This is mainly attributed
to electron transfer from porphyrin parts to ruthenium units,
but the intensity of 8 and 8–Zn is stronger than that of 4 and
4–Zn. This result suggests that energy transfer from Ru units
to porphyrin parts might occur in these macromolecules.
Emission intensity of the compounds 4–Zn, 8–Zn, and
ZnPRu are not proportionate (Fig. 4c), which is different
from that of the compounds 4, 8 and PH2Ru in Figure 4d.
This may be caused by trace of free compounds 4 and 8 in
4–Zn or 8–Zn, respectively. Further studies of the compli-
cated processes of electron or energy transfer occurring in
these systems will be conducted using femtosecond or pico-
second transient spectroscopy.
the triplet absorption of zinc porphyrin unit in 8–Zn in
CH3CN solution. The (p,p*) spectrum is marked by an
3
intense absorption at 480 nm and a distinct near-infrared
absorption peak, and its kinetic decay exhibits mono-
exponential behavior and excited state lifetime is
t¼432 ns (Fig. 5c). On the other hand, the transient absorp-
tion spectrum of 8-Zn-TiO2 is quite different from that of
8–Zn (Fig. 5b). The kinetic decay of 8-Zn-TiO2 shows di-
exponential behavior with lifetimes of charge separation
state of t1¼500 ns and t2¼15 ms (Fig. 5d). This result indi-
cates a long-lived charge separation obtained in the system,
which is very important for mimicking photosynthesis. To
investigate the details of the photoinduced electron transfer
and energy transfer processes occurring in the complexes
8–Zn and 8-Zn-TiO2, femtosecond transient absorption
measurements on this complex are in progress.
In conclusion, we outline in this paper an efficient route to-
ward the preparation of several new multicomponent arrays
based on porphyrin and ruthenium polypyridine, including
complexes 4, 8 and their Zn analogues 4–Zn, 8–Zn.
This is a system that consists of a porphyrin center and
one or more ruthenium polypyridine subunits. This kind of
structure was designed by considering structural morphol-
ogy and synthetic strategy. Preliminary investigations of
the electronic properties in solution and electrochemical
studies clearly revealed that electronic interactions in each
subunit are very weak. Steady and transient state spectra
recorded at room temperature show that intramolecular
2.5. Time-resolved absorbance
The preliminary transient absorptions and time-dependent
decays of 8–Zn and 8-Zn-TiO2 have been performed in
CH3CN solution using a YAG laser with a 12 ns pulse width
when exciting at 532 nm. Figure 5a shows the spectrum for
(a)
(b)
350
300
250
200
150
100
50
20
15
10
5
0
400
0
500
600
Wavelength (nm)
700
800
500
600
Wavelength (nm)
700
800
0.04
0.03
0.02
0.01
0.00
(c)
(d)
0.12
0.10
0.08
0.06
0.04
0.02
0.00
8-Zn
8-Zn-TiO2
480nm
480nm
432ns
500ns(4%)
15000ns(96%)
2000
2500
3000
Wavelength (nm)
3500
4000
50000 60000 70000 80000 90000 100000
Time (ns)
Figure 5. Transient absorption spectrum and time-dependent decay of 8–Zn and 8-Zn-TiO2 in deoxygenated CH3CN solutions (1ꢁ10ꢀ5 M). (a) Transient
absorption spectrum of 8–Zn. (b) Transient absorption spectrum of 8-Zn-TiO2 (0.5 M LiClO4). (c) Time-dependent decay of 8–Zn (lprobe¼480 nm).
(d) Time-dependent decay of 8-Zn-TiO2 (0.5 M LiClO4) (lprobe¼480 nm).

9202
X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
and intermolecular photoinduced electron or energy transfer
might occur depending on the concentrations.
6.0 mmol) were added to CH2Cl2 (1000 mL), which was de-
gassed with N2 for 30 min. After the mixture was stirred and
purged with N2 for a further 30 min, a BF3$Et2O solution
(1.0 mL, 2 M in CH2Cl2, 2.0 mmol) was added dropwise.
The reaction mixture was stirred overnight at room tempera-
ture. 2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) (1.82 g,
8.0 mmol) was added to the red-brown solution, and the re-
sulting black mixture was refluxed for 2 h. Et3N (1.12 mL,
8.0 mmol) was added to the mixture, and the solution was
concentrated to dryness under reduced pressure. The residue
was purified by column chromatography (silica gel, hexane/
CH2Cl2 50:50) to give the two desired porphyrin products.
3. Experimental
3.1. General
All reagents were purchased from Aldrich, and all solvents
were purified according to standard methods. Pyrrole was
freshly distilled before use. All of the manipulations were
1
performed under N2. H NMR spectra were recorded on
1
a Varian 400 spectrometer and reported in parts per million
downfield from TMS. CH2Cl2 (Aldrich, spectroscopic grade)
used for performance of electrochemistry was dried with
Porphyrin 1: 196 mg, 12%, mp>300 ꢂC; H NMR (CDCl3)
d ꢀ2.78 (br s, 2H, –NH), 1.61 (s, 18H, tert-butyl–H), 7.78
0
(d, J¼8.0 Hz, 4H, H7, H8, H12, H12 ), 8.14 (d, J¼8.0 Hz, 4H,
˚
0
0
0
0
molecular sieve (4 A) and then freshly distilled from CaH2
H5, H6, H11, H11 ), 8.40 (d, J¼8.0 Hz, 4H, H1, H1 , H7 , H8 ),
0 0 0
under N2. Cyclic voltammograms were recorded at a scan
rate of 50 mV/s in CH2Cl2 solutions (10ꢀ3 M) using
Bu4NPF6 (0.05 M) as a supporting electrolyte. Electrochem-
ical measurements were recorded using a BAS-100 W elec-
trochemical potentiostat. The electrolyte solution was
degassed by bubbling with dry argon for 10 min before mea-
surements. Cyclic voltammograms were obtained in a three-
electrode cell under argon. The working electrode was
a glassy carbon disc (diameter 3 mm) successively polished
with 3 and 1 mm diamond pastes and sonicated in ion-free
water for 10 min. The reference electrode was a non-aqueous
Ag/Ag+ electrode (0.01 M AgNO3 in CH3CN) and the auxil-
iary electrode was a platinum wire. The measured potentials
in Figure 3 are corrected to the values of SCE by adding
0.30 V. In order to assign easily the protons in the complexes,
we showed the numbering scheme of the complex 4 in
Figure 6.
8.65 (d, J¼8.0 Hz, 4H, H2, H2 , H5 , H6 ), 8.73 (d, J¼4.8 Hz,
2H, pyrrolyl H), 8.78 (s, 2H, pyrrolyl H), 8.91 (s, 2H, pyrrolyl
H), 8.96 (d, J¼4.8 Hz, 2H, pyrrolyl H); 13C NMR (CDCl3)
d 31.9, 35.1, 117.1, 122.1, 123.9, 134.7, 135.3, 138.8, 147.9,
149.2, 151.1; APCI-MS positive: [M+H]+(m/z¼817.4).
Anal. Calcd for C52H44N6O4$0.1CH2Cl2: C, 75.81; H, 5.40;
N, 10.18. Found: C, 76.00; H, 5.52; N, 10.26.
Porphyrin 5: 193 mg, 12%, mp>300 ꢂC; 1H NMR (CDCl3)
d ꢀ2.80 (br s, 2H, –NH), 1.62 (s, 9H, tert-butyl–H), 7.80 (d,
J¼8.8 Hz, 2H, H7, H8), 8.13 (d, J¼8.0 Hz, 2H, H5, H6), 8.40
0
0
0
0
(d, J¼8.4 Hz, 6H, H1, H1 , H7 , H8 , H12, H12 ), 8.66 (d,
0
0
0
0
J¼8.8 Hz, 6H, H2, H2 , H5 , H6 , H11, H11 ), 8.76 (d,
0
0
J¼4.8 Hz, 2H, H4, H9), 8.80 (s, 4H, H3, H3 , H10, H10 ),
8.98 (d, J¼4.8 Hz, 2H, H4 , H9 ); 13C NMR (CDCl3)
d 31.9, 35.1, 113.6, 120.0, 120.6, 123.8, 131.1, 132.8,
134.7, 135.9, 139.5, 146.1, 150.6; APCI-MS positive:
[M+H]+(m/z¼806.3). Anal. Calcd for C48H35N7O6$0.5CH2
Cl2: C, 68.67; H, 4.28; N, 11.56. Found: C, 68.92; H, 4.61;
N, 11.90.
0
0
7
5
8
6
COOEt
17'
14'
3.3. 5,10-Bis(4-aminophenyl)-15,20-bis(4-tert-butylphe-
nyl)porphyrin (2)
15'
18'
13'
13
16'
19'
9
4
N
N
3
10
O
2
1
12 11
12' 11'
NH
N
N
15
N
COOEt
Ru
To a solution of 1 (408 mg, 0.5 mmol) in 1:2 of CHCl3/
HOAc (45 mL) was added a solution of SnCl2$2H2O
(915 mg, 4.0 mmol) in concentrated HCl (25 mL). The mix-
ture was vigorously stirred in a preheated oil bath (65–
70 ꢂC) for 30 min, refluxed overnight, and then neutralized
with ammonia solution (25%) to pH 8–9. Chloroform
(100 mL) was added, and the mixture was stirred for 1 h.
The organic phase was separated, and the water phase was
extracted with CHCl3 (2ꢁ100 mL). The combined organic
layer was washed one time with dilute ammonia solution,
three times with water, and then concentrated to dryness.
The residue was purified by column chromatography (silica
gel, CH2Cl2/CH3CH2OH 200:1) to give the desired porphy-
rin product (301 mg, 80%): mp>300 ꢂC; 1H NMR (CDCl3)
d ꢀ2.72 (br s, 2H, –NH), 1.60 (s, 18H, tert-butyl–H), 3.98 (br
N
H
21'
21
14
20'
18
N
HN
N
N
2' 1'
20
10'
3'
17
4'
9'
16
19
COOEt
EtOOC
5'
7'
6'
8'
O
HN
13''
13'''
14'''
15'''
14''
N
N
N
15''
17''
17'''
18''
18'''
N
EtOOC
N
Ru
COOEt
16'''
19'''
16''
N
21'''
21''
19''
20''
20'''
EtOOC
COOEt
4
0
s, 4H, –NH2), 7.03 (d, J¼8.4 Hz, 4H, H5, H6, H11, H11 ), 7.74
Figure 6. The numbering scheme of compound 4 (arbitrary numbering).
0
(d, J¼8.0 Hz, 4H, H7, H8, H12, H12 ), 7.99 (d, J¼8.0 Hz, 4H,
0
0
0
0
0
0
3.2. 5,10-Bis(4-nitrophenyl)-15,20-bis(4-tert-butylphe-
nyl)porphyrin (1) and 5,10,15-tris(4-nitrophenyl)-20-(4-
tert-butylphenyl)porphyrin (5)
H2, H2 , H5 , H6 ), 8.14 (d, J¼8.0 Hz, 4H, H1, H1 , H7 , H8 ),
8.86–8.91 (m, 8H, pyrrolyl H). 13C NMR (CDCl3) d 31.9,
35.1, 113.6, 120.0, 120.6, 123.8, 131.1, 132.8, 134.7,
135.9, 139.5, 146.1, 150.6; APCI-MS positive: [M+H]+
(m/z¼757.5). Anal. Calcd for C52H48N6$0.75CH3CH2OH: C,
81.18; H, 6.69; N, 10.62. Found: C, 81.58; H, 6.83; N, 10.21.
Pyrrole (0.56 mL, 8.0 mmol), 4-nitrobenzaldehyde (306 mg,
2.0 mmol), and 4-tert-butylbenzaldehyde (1.04 mL,

X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
9203
3.4. Porphyrin-(NHCO-bpy)2 (3)
3.6. Zn-porphyrin-{NHCO-bpy-Ru[(bpy)-
(COOEt)2]}2[PF6]4 (4–Zn)
A mixture of 40-methyl-2,20-bipyridine-4-carboxylic acid
(350 mg, 1.64 mmol) and SOCl2 (20 mL) was refluxed for
2 h. After removing excess of SOCl2 by distillation under re-
duced pressure, the acid chloride product was obtained and
dried in vacuum at 70 ꢂC for 1 h. Then dry CH2Cl2
(12 mL) was added and the mixture was stirred for 5 min
at 50 ꢂC. The resulting light yellow solution was added drop-
wise to the CH2Cl2 (30 mL) solution of 2 (268 mg,
0.35 mmol) in which two drops of Et3N was preadded.
White smoke was observed in the reaction flask. The mixture
was refluxed overnight, and washed with aqueous ammonia
solution (5%) and then water. After removing the solvent,
the residue was dissolved in CHCl3 (20 mL) and then
CH3CN (200 mL) was added dropwise. Precipitate was
formed by slowly evaporating CHCl3 under vacuum. The de-
sired product was obtained after column chromatography on
silica gel with a mixture of CH2Cl2/MeOH (95:5) as eluent
A solution of Zn(OAc)2$2H2O (20 mg, 0.100 mmol) in
ethanol (2 mL) was added to a solution of 4 (80 mg,
0.025 mmol) in chloroform (15 mL), and stirred at room
temperature overnight under N2 in the dark. This mixture
was washed with water, evaporated to dryness, and purified
by CH2Cl2/MeOH (10:1). The desired product was obtained
1
as a red-brown solid (76 mg, 95%): mp>250 ꢂC; H NMR
(CD3CN) d 1.41–1.46 (m, 24H, –COOCH2CH3), 1.62 (s,
18H, tert-butyl), 2.63 (s, 6H, bpy–CH3), 4.46–4.52 (m, 8H,
0
000
–COOCH2CH3), 7.36 (d, J¼6.0 Hz, 2H, H14 , H14 ), 7.56
0
000
(d, J¼5.2 Hz, 2H, H15 , H15 ), 7.82–7.88 (m, 8H, H7, H8,
0
H12, H12 , H14, H15, H15 , H15 ), 7.93–8.06 (m, 16H, H17,
00
00
0
H17 , H17 , H17 , H18, H18 , H18 , H18 , H20, H20 , H20 ,
00
000
0
00
000
0
00
000
0
00
000
H20 , H21, H21 , H21 , H21 ), 8.15 (d, J¼8.0 Hz, 4H,
0
0
0
H5, H6, H11, H11 ), 8.19 (d, J¼8.8 Hz, 4H, H1, H1 , H7 ,
0
0
0
H8 ), 8.69 (s, 2H, H13 ), 8.86–8.93 (m, 8H, H3, H3 , H4,
1
to give purple solid (242 mg, 60%): mp>250 ꢂC; H NMR
H4 , H9, H9 , H10, H10 ), 9.07–9.13 (m, 10H, H13, H13 ,
0
0
0
00
0
00
000
0
00
000
(CDCl3) d ꢀ2.75 (br s, 2H, –NH), 1.58 (s, 18H, tert-butyl–
H16, H16 , H16 , H16 , H19, H19 , H19 , H19 ), 9.68 (br s,
2H, amide–H); API-ES-MS m/z: [Mꢀ2PF6]2+ 1452.0,
[Mꢀ3PF6]3+ 921.0, [Mꢀ4PF6]4+ 654.0. Anal. Calcd for
C140H126F24N18O18P4ZnRu2$1.2CH2Cl2: C, 51.42; H, 3.92;
N, 7.64. Found: C, 51.69; H, 3.67; N, 7.39.
0
H), 2.48 (s, 6H, bpy-CH3), 7.21 (d, J¼4.8 Hz, 2H, H14
,
000
0
H14 ), 7.71 (d, J¼8.0 Hz, 4H, H5, H6, H11, H11 ), 7.96 (d,
00
J¼3.2 Hz, 2H, H14, H14 ), 8.05 (d, J¼8.4 Hz, 4H, H7, H8,
0
0
0
0
H12, H12 ), 8.09 (d, J¼8.0 Hz, 4H, H2, H2 , H5 , H6 ), 8.20
0
0
0
0
,
(d, J¼8.4 Hz, 4H, H1, H1 , H7 , H8 ), 8.34 (s, 2H, H13
000
0
000
H13 ), 8.59 (d, J¼5.2 Hz, 2H, H15 , H15 ), 8.68 (s, 2H,
3.7. 5,10,15-Tris(4-aminophenyl)-20-(4-tert-butylphe-
nyl)porphyrin (6)
amide–H), 8.85–8.86 (m, 8H, pyrrolyl–H), 8.88–8.91 (m,
4H, H13, H13 , H15, H15 ); 13C NMR (CDCl3) d 21.5, 31.9,
35.1, 117.6, 118.8, 119.2, 120.6, 121.7, 122.3, 122.6,
123.5, 125.7, 131.5, 133.3, 134.6, 135.4, 137.4, 139.2,
143.3, 149.1, 150.6, 155.1, 156.9, 163.6; APCI-MS positive:
[M+H]+ (m/z¼1149.5). Anal. Calcd for C76H64N10
O2$0.4CH2Cl2: C, 77.54; H, 5.52; N, 11.84. Found: C,
77.82; H, 5.74; N, 12.00.
00
00
To a solution of 5 (402 mg, 0.5 mmol) in 1:2 of CHCl3/
HOAc (45 mL) was added a solution of SnCl2$2H2O
(915 mg, 4.0 mmol) in concentrated HCl (25 mL). The mix-
ture was vigorously stirred in a preheated oil bath (65–
70 ꢂC) for 30 min, refluxed overnight, and then neutralized
with ammonia solution (25%) to pH 8–9. Chloroform
(100 mL) was added and the mixture was stirred for 1 h.
The organic phase was separated and the water phase was ex-
tracted with CHCl3 (2ꢁ100 mL). The combined organic
layer was washed one time with dilute ammonia solution,
three times with water, and then concentrated to dryness.
The residue was purified by column chromatography (silica
gel, CH2Cl2/CH3CH2OH 200:1) to give the desired porphy-
rin product (304 mg, 85%): mp>300 ꢂC; 1H NMR (CDCl3)
d ꢀ2.71 (br s, 2H, –NH), 1.61 (s, 9H, tert-butyl–H), 3.99 (br
3.5. Porphyrin-{NHCO-bpy-Ru[(bpy)-
(COOEt)2]}2[PF6]4 (4)
A mixture of 3 (100 mg, 0.087 mmol) and Ru[bpy-
(COOEt)2]2Cl2 (134 mg, 0.174 mmol) in acetic acid
(10 mL) was refluxed for 1 h under N2 in the dark. After re-
moving the solvent, the product was purified by chromato-
graphy on silica gel with a mixture of CH2Cl2/MeOH
(20:1) as eluent, and the anion was exchanged with
NH4PF6. The desired product was obtained as a red-brown
solid (95 mg, 35%): mp>250 ꢂC; 1H NMR (CD3CN)
0
0
0
s, 6H, –NH2), 7.04 (d, J¼8.4 Hz, 6H, H2, H2 , H5 , H6 , H11,
0
H11 ), 7.74 (d, J¼8.0 Hz, 2H, H5, H6), 7.99 (d, J¼8.4 Hz, 6H,
0
0
0
0
H1, H1 , H7 , H8 , H12, H12 ), 8.13 (d, J¼8.4 Hz, 2H, H7, H8),
8.84–8.90 (m, 8H, pyrrolyl–H); 13C NMR (CDCl3) d 31.9,
35.1, 113.6, 119.5, 120.4, 123.8, 131.2, 132.8, 134.6,
135.9, 140.1, 146.1, 150.5; APCI-MS positive: [M+H]+
(m/z¼716.5). Anal. Calcd for C48H41N$0.5CH3CH2OH: C,
79.65; H, 6.00; N, 13.27. Found: C, 79.91; H, 6.05; N, 12.88.
d ꢀ2.82 (br s, 2H, –NH), 1.42–1.47 (m, 24H,
–COOCH2CH3), 1.61 (s, 18H, tert-butyl), 2.64 (s, 6H,
bpy–CH3), 4.48–4.52 (m, 16H, –COOCH2CH3), 7.36 (d,
0
000
0
J¼5.6 Hz, 2H, H14 , H14 ), 7.57 (d, J¼5.6 Hz, 2H, H15
,
H15 ), 7.85–7.87 (m, 8H, H7, H8, H12, H12 , H14, H15,
000
0
00
00
0
00
000
H14 , H15 ), 7.93–8.05 (m, 16H, H17, H17 , H17 , H17 , H18,
0
00
000
0
00
000
H18 , H18 , H18 , H20, H20 , H20 , H20 , H21, H21 , H21 ,
0
00
3.8. Porphyrin-(NHCO-bpy)3 (7)
000
0
H21 ), 8.16 (d, J¼8.4 Hz, 4H, H5, H6, H11, H11 ), 8.23 (d,
A mixture of 40-methyl-2,20-bipyridine-4-carboxylic acid
(434 mg, 2.03 mmol) and SOCl2 (20 mL) was refluxed for
2 h. After removing excess of SOCl2 by distillation under re-
duced pressure, the acid chloride was obtained, and dried in
vacuum at 70 ꢂC for 1 h. Then dry CH2Cl2 (12 mL) was
added and the mixture was stirred for 5 min at 50 ꢂC. The re-
sulting light yellow solution was added dropwise to the
CH2Cl2 (30 mL) solution of 6 (236 mg, 0.33 mmol) in which
0
0
0
J¼8.4 Hz, 4H, H1, H1 , H7 , H8 ), 8.30 (d, J¼8.4 Hz, 4H,
0
H2, H2 , H5 , H6 ), 8.69 (s, 2H, H13 , H13 ), 8.88–8.95 (m,
0
0
0
000
0
8H, H3, H3 , H4, H4 , H9, H9 , H10, H10 ), 9.09–9.13 (m,
0
0
0
00
0
00
000
0
10H, H13, H13 , H16, H16 , H16 , H16 , H19, H19 , H19 ,
00
000
H19 ), 9.56 (br s, 2H, amide–H); API-ES-MS m/z:
[Mꢀ2PF6]2+ 1421.4, [Mꢀ3PF6]3+ 899.1, [Mꢀ4PF6]4+
638.0. Anal. Calcd for C140H128F24N18O18P4Ru2$CH2Cl2:
C, 52.63; H, 4.07; N, 7.84. Found: C, 52.99; H, 3.89; N, 7.49.

9204
X. Liu et al. / Tetrahedron 63 (2007) 9195–9205
two drops of Et3N was preadded. White smoke was observed
in the reaction flask. The mixture was refluxed overnight,
washed with 5% of aqueous ammonia solution, and then
with water. After removing the solvent, the residue was dis-
solved in CHCl3 (20 mL) and CH3CN (200 mL) was added
dropwise. Precipitate was formed by slowly evaporating
CHCl3 under vacuum. The desired product was obtained af-
ter column chromatography on silica gel with a mixture of
CH2Cl2/MeOH (90:10) as eluent to give purple solid
purified by CH2Cl2/MeOH (10:1). The desired product
was obtained as a red-brown solid (56 mg, 95%):
mp>250 ꢂC; 1H NMR (CD3CN) d 1.40–1.44 (m, 36H,
–COOCH2CH3), 1.60 (s, 9H, tert-butyl), 2.61 (s, 3H, bpy–
CH3), 4.45–4.52 (m, 24H, –COOCH2CH3), 7.35 (d,
0
000
00000
J¼7.6 Hz, 3H, H14 , H14 , H14 ), 7.53 (d, J¼5.2 Hz, 3H,
0
000
00000
H15 , H15 , H15 ), 7.82–8.03 (m, 32H, H7, H8, H14, H14
00
,
0000
H14 , H15, H15 , H15 H17, H17 , H17 , H17 , H17 H17
00
0000
0
00
000
0000
00000
000
,
,
,
0
00
000
0000
00000
0
00
H18, H18 , H18 , H18 , H18 H18 H20, H20 , H20 , H20 ,
,
,
1
(279 mg, 65%): mp>250 ꢂC; H NMR (CDCl3) d ꢀ2.76
0000
H20 H20 H21, H21 , H21 , H21 , H21 H21 ), 8.16 (d,
00000
0
00
000
0000
00000
,
,
,
0
(br s, 2H, –NH), 1.56 (s, 9H, tert-butyl–H), 2.47 (s, 9H,
J¼7.6 Hz, 2H, H5, H6), 8.19 (d, J¼8.8 Hz, 6H, H1, H1 ,
0
bpy–CH3), 7.19–7.21 (m, 3H, H14 , H14 , H14 ), 7.65 (d,
000
00000
0
0
0
H7, H7 , H12, H12 ), 8.25 (d, J¼8.8 Hz, 6H, H2, H2 ,
0 0 0 0 000 00000
00
J¼7.2 Hz, 2H, H5, H6), 7.94–7.96 (m, 3H, H14, H14 ,
H5 , H6 , H11, H11 ), 8.68 (s, 3H, H15 , H15 , H15 ), 8.86–
00
8.92 (m, 8H, pyrrolyl–H), 9.06–9.12 (m, 15H, H13, H13 ,
0000
H14 ), 8.00–8.07 (m, 8H, H2, H2 , H5 , H6 , H7, H8, H11,
0
0
0
0
0000
0
00
000
0000
00000
0
H13 H16, H16 , H16 , H16 , H16 , H16 , H19, H19 , H19 ,
00
H11 ), 8.15 (d, J¼7.6 Hz, 2H, H1, H12), 8.20 (d, J¼8.4 Hz,
,
0
0
0
0
0
000
4H, H1 , H7 , H8 , H12 ), 8.32–8.33 (m, 3H, H13 , H13 ,
000
0000
00000
H19 , H19 H19 ), 9.56 (br s, 3H, amide–H); API-
,
ES-MS m/z: [Mꢀ3PF6]3+ 1302.1, [Mꢀ4PF6]4+ 940.0,
[Mꢀ5PF6]5+ 723.0, [Mꢀ6PF6]6+ 579.1. Anal. Calcd for
C180H159F36N25O27P6Ru3Zn$EtOH: C, 49.81; H, 3.79; N,
7.98. Found: C, 49.61; H, 3.92; N, 7.61.
00000
0
000
00000
H13 ), 8.57–8.59 (m, 3H, H15 , H15 , H15 ), 8.73 (s, 3H,
00
amide–H), 8.85–8.91 (m, 14H, pyrrole-8H, H13, H13 ,
0000
H13 H15, H15 , H15 ); 13C NMR (CDCl3) d 21.4, 31.8,
00
0000
,
34.9, 117.8, 118.8, 119.5, 122.1, 122.5, 123.7, 125.5,
134.5, 135.3, 137.5, 138.9, 143.2, 148.9, 149.0, 150.5,
155.1, 157.2, 164.5; APCI-MS positive: [M+H]+ (m/z¼
1304.4). Anal. Calcd for C84H65N13O3$1.5EtOH: C, 76.07;
H, 5.43; N, 13.26. Found: C, 76.09; H, 5.35; N, 13.06.
Acknowledgements
Financial support of this work from the following sources is
gratefully acknowledged: The Swedish Energy Agency and
Swedish Research Council (VR), China Natural Science
Foundation (Grant 20128005 and 20672017), The Minis-
try of Science and Technology (MOST) (Grant
2001CCA02500), and The Ministry of Education. The
authors thank Ms. Xin-Mei Fu for MS measurements,
Dr. Tomas Polivika and Ms. Kun Jin for helpful discussion.
3.9. Porphyrin-{NHCO-bpy-Ru[(bpy)-
(COOEt)2]}3[PF6]6 (8)
A mixture of 7 (100 mg, 0.087 mmol) and Ru[bpy-
(COOEt)2]2Cl2 (134 mg, 0.174 mmol) in acetic acid
(30 mL) was refluxed for 1 h under N2 in the dark. After re-
moving the solvent, the product was purified by column
chromatography on silica gel with a mixture of CH2Cl2/
MeOH (20:1) as eluent, and the anion was exchanged with
NH4PF6. The desired product was obtained as a red-brown
solid (95 mg, 35%): mp>250 ꢂC; 1H NMR (CD3CN)
References and notes
1. (a) Collin, J.-P.; Harriman, A.; Heitz, V.; Odobel, F.; Sauvage,
J.-P. Coord. Chem. Rev. 1996, 148, 63–69; (b) Harriman, A.;
Hissler, M.; Trompette, O.; Ziessel, R. J. Am. Chem. Soc.
1999, 121, 2516–2525; (c) Uyeda, H. T.; Zhao, Y.; Wostyn,
K.; Asselberghs, I.; Clays, K.; Persoons, A.; Therien, M. J.
J. Am. Chem. Soc. 2002, 124, 13806–13813; (d) Ambroise,
A.; Wagner, R. W.; Rao, P. D.; Riggs, J. A.; Hascoat, P.;
Diers, J. R.; Seth, J.; Lammi, R. K.; Bocian, D. F.; Holten, D.;
Lindsey, J. S. Chem. Mater. 2001, 13, 1023–1034; (e) Liu, X.;
Liu, J.; Jin, K.; Yang, X.; Peng, Q.; Sun, L. Tetrahedron 2005,
61, 5655–5662; (f) Liu, X.; Liu, J.; Pan, J.; Chen, R.; Na, Y.;
Gao, W.; Sun, L. Tetrahedron 2006, 62, 3674–3680; (g)
Sessler, J. L.; Capuano, V. L.; Burrell, A. K. Inorg. Chim.
Acta 1993, 204, 93–101.
d ꢀ2.80 (s, br, 2H, –NH), 1.40–1.44 (m, 36H,
–COOCH2CH3), 1.60 (s, 9H, tert-butyl), 2.61 (s, 9H, bpy–
CH3), 4.46–4.49 (m, 24H, –COOCH2CH3), 7.34 (d,
0
000
00000
0
J¼5.2 Hz, 3H, H14 , H14 , H14 ), 7.54–7.58 (m, 3H, H15
,
,
,
000
H15 , H15 ), 7.82–7.87 (m, 8H, H7, H8, H14, H15, H14
00000
00
00
00
H15 , H14 , H15 ), 7.91–8.02 (m, 24H, H17, H17 , H17
000
H17 , H17 H17 H18, H18 , H18 , H18 , H18 , H18 , H20,
0000
0000
0
0000
00000
0
00
000
0000
00000
,
,
0
00
000
0000
00000
0
00
000
0000
H20 , H20 , H20 , H20 H20 H21, H21 , H21 , H21 , H21
,
,
,
00000
H21 ), 8.16 (d, J¼7.6 Hz, 2H, H5, H6), 8.21 (d, J¼8.4 Hz,
0
0
0
0
6H, H1, H1 , H7 , H8 , H12, H12 ), 8.28 (d, J¼8.4 Hz, 6H,
0
H2, H2 , H5 , H6 , H11, H11 ), 8.66 (s, 3H, H13 , H13 ,
0
0
0
0
000
00000
H13 ), 8.87–8.94 (m, 8H, pyrrolyl–H), 9.08–9.11 (m,
00000
15H, H13, H13 , H13 H16, H16 , H16 , H16 , H16 H16
,
00
0000
0
00
000
0000
,
,
0
00
000
0000
00000
H19, H19 , H19 , H19 ,H19 H19 ), 9.71(br s, 3H, amide–
2. Jovanovich, H. B. Photochemistry of Polypyridine and
Porphyrin Complexes; Academic: New York, NY, 1992.
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,
H); API-ES-MS m/z: [Mꢀ3PF6]3+ 1281.2, [Mꢀ4PF6]4+
924.7, [Mꢀ5PF6]5+ 710.7, [Mꢀ6PF6]6+ 568.6. Anal. Calcd
for C180H161F36N25O27P6Ru3: C, 50.52; H, 3.79; N, 8.18.
Found: C, 50.18; H, 3.97; N, 7.82.
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temperature overnight under N2 in the dark. This mixture
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