Change in supramolecular networks through in situ esterification of porphyrins

Article abstract of DOI:10.1002/ejic.200900801

A series of porphyrins, M[TCPP-Et₄] [M = Zn (1), Cu (2), and Ni (3) Et = CH₂CH₃; TCPP = meso-tetra(4-carboxyphenyl) porphyrin], M[TCPP-Me₄] [M = Zn (4), Cu (S), and Co (6); Me = CH ₃], and two nonmeta

Full text of DOI:10.1002/ejic.200900801

FULL PAPER
DOI: 10.1002/ejic.200900801
Change in Supramolecular Networks through In Situ Esterification of
Porphyrins
Wentong Chen[a,b] and Shunichi Fukuzumi*[a]
Keywords: Solid-state structures / Esterification / Porphyrinoids / Phosphorescence / Luminescence / Nitrogen heterocycles
A series of porphyrins, M[TCPP-Et4] [M = Zn (1), Cu (2), and
Ni (3); Et = CH2CH3; TCPP = meso-tetra(4-carboxyphenyl)-
porphyrin], M[TCPP-Me4] [M = Zn (4), Cu (5), and Co (6);
Me = CH3], and two nonmetalated compounds, TCPP-Et4 (7)
and TCPP-Me4·H2O (8), were synthesized by solvothermal
reactions and characterized by single-crystal X-ray diffrac-
tion. Compounds 1–3 feature an isolated structure with a
planar macrocycle and an embedded metal-ion coordinating
to four pyrrole nitrogen atoms. Compound 4 is characterized
as a two-dimensional coordination polymer, and the zinc ion
coordinates to four nitrogen atoms and two oxygen atoms.
Compound 4 possesses a large void space (361 Å3), which
corresponds to 14% of the unit-cell volume. Compounds 5
and 6 are characteristic of an isolated motif with a four-coor-
dinate metal ion and a saddle-distorted nonplanar porphyrin
macrocycle. Nonmetalated compounds 7 and 8 also show an
isolated structure with a planar macrocycle. For compounds
1–3 and 7, the TCPP is esterified with ethanol, while for com-
pounds 4–6 and 8, the TCPP is esterified with methanol. The
molecules in 1 and 6–8 are interconnected by hydrogen
bonds and π–π interactions to yield 3D supramolecular net-
works, while in 2–5, 2D supramolecular motifs are formed.
The reaction mechanism was explored. Esterification plays
an important role in changing the properties of the com-
pounds as well as in the formation of different structural mo-
tifs and supramolecular networks. The UV/Vis, FTIR, fluores-
cence, phosphorescence, and MALDI-TOF MS spectra,
quantum yields, luminescence lifetimes, and cyclic voltam-
mograms were also studied in detail.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
tion and emission spectral, and redox properties of por-
phyrins. Thus, extensive efforts have been devoted to the
preparation and chemical transformation of porphyrins
into new porphyrin derivatives bearing reformative charac-
teristics that may enable them to be used in practical appli-
cations.[25–29]
Introduction
Porphyrins are among the most widely studied chemical
systems with abundant properties, and the vital roles played
by porphyrins in nature have been known for decades, as
well as their applications in catalysis, medicine, solar energy
conversion, amongst others.[1–12] The aggregation and self-
assembly of porphyrins are an area of intense research, and
so far, many porphyrin supramolecular assemblies, which
can be used as molecular-level electronics, sensors, photonic
materials, and for molecular recognition, have been pre-
pared through noncovalent interactions such as π–π stack-
ing interactions and hydrogen–bonding interactions.[13–24]
The coordination of metal ions at the center of the porphy-
rin ring, as well as the substitution at the periphery of the
porphyrin rings by suitable organic groups, provide various
programming elements for the design of porphyrin supra-
molecular assemblies. The modification through peripheral
substitutions can change the chemical, electronic absorp-
Multifarious substituent groups in numerous organic re-
actions have been utilized to decorate the periphery of por-
phyrins. However, esterification of porphyrins has scarcely
been reported. The large, rigid and square-planar symmetri-
cal meso-tetra(4-carboxyphenyl)porphyrin (TCPP) mole-
cule with divergent carboxylic groups is an extraordinary
building block for supramolecular self-assemblies. Met-
alation of the TCPP core usually serves to strengthen the
structural rigidity and it is accompanied with deprotonation
of the TCPP molecule during the reaction to account for
charge equilibrium, without the requirement of incorpora-
tion of other counteranions. Besides metalation and depro-
tonation, esterification is the third most important charac-
teristic of TCPP because of its carboxylic groups that can
possibly be esterified. However, the structures and functions
of TCPP supramolecules have yet to be explored.
[a] Department of Material and Life Science, Graduate School of
Engineering, Osaka University,
Suita, SORST, Japan Science Technology Agency,
Osaka 565-0871, Japan
We report herein the synthesis, X-ray crystal structures,
and properties of a series of esterified porphyrin com-
pounds, M[TCPP-Et4] [M = Zn (1), Cu (2), and Ni (3)],
M[TCPP-Me4] [M = Zn (4), Cu (5) and Co (6)], and two
nonmetalated compounds TCPP-Et4 (7) and TCPP-
E-mail: fukuzumi@chem.eng.osaka-u.ac.jp
[b] School of Chemistry and Chemical Engineering, Jinggangshan
University,
Ji’an, Jiangxi 343009, P. R. China
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200900801.
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Change in Supramolecular Networks through In Situ Esterification of Porphyrins
Scheme 1. Schematic diagram of the reaction mechanism (taking compound 2 as an example).
Me4·H2O (8), which were obtained by solvothermal reac- ripheral esterification, the porphyrins dissolve well in
tions. It should be noted that the title compounds cannot CHCl3 but are insoluble in ethanol and methanol.
be prepared by the traditional solution method because the
The IR spectra of 1–8 display similar features, and the
high temperatures and pressures necessary for esterification bands mainly appear in the range 700–1750 cm–1, as shown
cannot be achieved. The title compounds were charac- in Figure S2 (see Supporting Information). From the IR
terized in detail by using single-crystal X-ray diffraction, spectra of free-base TCPP, there are two bands observed at
UV/Vis, FTIR, fluorescence and phosphorescence spec- ca. 3319 and ca. 967 cm–1, which correspond to the νN–H
troscopy, quantum yields, luminescence lifetimes, cyclic vol- and δN–H vibrations of the pyrrole rings. These two bands
tammetry, and MALDI-TOF MS spectrometry. It should can also be found in the IR spectra of the nonmetalated
be pointed out that the title compounds were synthesized compounds TCPP-Et4 (7) and TCPP-Me4·H2O (8), in good
by using in situ esterification construction methods.
agreement with the fact that the N–H bonds of the pyrrole
To the best of our knowledge, only several compounds rings are still intact in 7 and 8. However, in the IR spectra
containing both TCPP and ester groups have been docu- of 1–6, these two bands disappear as result of the deproton-
mented thus far, and for most of these compounds, the ester ation and the metalation of the pyrrole rings. This result
groups were introduced from the starting materials.[30,31] As proves that the free-base porphyrin is converted into a
for the reaction mechanism of preparing the title com- metalloporphyrin.
pounds, we propose the following logical process: TCPP un-
dergoes a deprotonation and metalation procedure, fol-
lowed by esterification (Scheme 1). The vital role, played by
the esterification in tuning the properties and supramolec-
ular networks, was explored for the first time.
Crystal Structures
M[TCPP-Et4] [M = Zn (1), Cu (2), Ni (3), and H2
(7)] and TCPP-Me4·H2O (8)
We found that supramolecular networks were controlla-
ble, namely, supramolecular networks can be easily adjusted
by the esterification under solvothermal conditions. To the
best of our knowledge, although many porphyrins have so
far been reported, investigations on the ability of esterifica-
tion to tune the supramolecular networks have yet to be
performed. Moreover, this work provides a convenient syn-
thetic method for the esterification of porphyrins.
The selected bond lengths and angles are presented in
Table 1, and a summary of the crystallographic data and
structure analyses is listed in Table 5.
X-ray diffraction analysis reveals that the structures of
compounds 1–3, 7, and 8 have a common feature despite
different cells (but, incidentally, the same space group), and
herein compound 1 is presented as an example and dis-
cussed in detail.
The molecular structure of 1 is depicted as an ORTEP
drawing in Figure 1. Compound 1 consists of neutral
Zn[TCPP-Et4] molecules and crystallizes in the space group
P21/c. The Zn2+ ion resides in a crystallographic inversion
Results and Discussion
General Characterization
For all the title compounds, the MALDI-TOF MS spec- center and has an approximately ideal square-planar geom-
tra in CHCl3 (matrix: CHCA; negative mode) exhibit mo- etry without axial ligation. The bond lengths from the zinc
lecular peak values that are consistent with the correspond- ion (at the center of the almost perfectly planar porphyrin
ing calculated exact mass numbers (see Supporting Infor- macrocycle) to the pyrrole nitrogen atoms are in the range
mation, Figure S1). This indicates that all the compounds 2.040(2)–2.051(2) Å in 1, which is comparable to that found
maintain their structures in solution as in the solid state. As in the literature.[32–42] Bond valence calculations indicate
for the solubility, it has a dramatic change before and after that the zinc ion is in a +2 oxidation state [Zn1: 1.90].[43]
the peripheral modification of the porphyrins. Before pe- The distortion angles of the phenyl rings with respect to
ripheral esterification, TCPP dissolves well in ethanol and the macrocycle plane are 52.37(6)° and 85.79(8)°. All four
methanol, but is insoluble in CHCl3. In contrast, after pe- carboxylic groups are esterified with ethanol molecules.
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Table 1. Selected bond lengths [Å] and bond angles [°].
There is no solvent molecule in the crystal structure, and
the closest Zn–porphyrin plane distance inside one unit cell
is 8.417(3) Å with a plane dihedral angle of 0°. In 1, the
abundant C–H···π interactions bridge the molecules to con-
struct a 3D supramolecular network (Figure 2). It is note-
worthy that the C19–H···π interaction between one of the
ester groups (shown enclosed in a circle in Figure 2) and
a neighboring phenyl ring plays an important role in the
formation of the 3D supramolecular network. If this C19–
H···π interaction were absent, a 2D supramolecular struc-
ture would form rather than a 3D supramolecular network.
1
Zn1–N1ϫ2
Zn1–N2ϫ2
2.051(2)
2.040(2)
N2–Zn1–N1ϫ2
90.62(7)
89.38(7)
180.00(9)
N2#1–Zn1–N1ϫ2[a]
N2–Zn1–N2#1[a] 180.00(6) N1#1–Zn1–N1[a]
2
Cu1–N1ϫ2
Cu1–N2ϫ2
1.994(2)
1.997(1)
N2–Cu1–N1ϫ2
89.99(7)
N2#1–Cu1–N1ϫ2[b] 90.01(7)
N2–Cu1–N2#1[b] 180.0(1)
N1#1–Cu1–N1[b]
180.0(1)
3
Ni1–N1ϫ2
1.957(1)
1.954(2)
N2–Ni1–N1ϫ2
89.82(6)
90.18(6)
180.00(5)
Ni1–N2ϫ2
N2#1–Ni1–N1ϫ2[c]
N2–Ni1–N2#1[c]
180.00(5) N1#1–Ni1–N1[c]
4
Zn1–N1ϫ2
2.030(2)
2.046(2)
2.543(2)
N2–Zn1–N1ϫ2
90.27(9)
89.73(9)
180.000(1)
Zn1–N2ϫ2
N2#2–Zn1–N1ϫ2[e]
N1#2–Zn1–N1[e]
Zn1–O3#1ϫ2[d]
N2–Zn1–N2#2[e] 180.00(0)
5
Cu1–N1
Cu1–N2
Cu1–N3
Cu1–N4
1.974(2)
1.983(2)
1.981(2)
1.994(2)
90.35(8)
N1–Cu1–N3
N1–Cu1–N4
N2–Cu1–N3
N2–Cu1–N4
N3–Cu1–N4
173.94(9)
89.63(8)
90.07(8)
175.26(9)
90.45(8)
N1–Cu1–N2
6
Figure 2. Packing diagram of 1 with the dashed lines representing
C–H···π interactions [the circle highlights the ester carbon atom
involved in the formation of a C19–H···π interaction]. Represented
Co1–N1
Co1–N2
Co1–N3
Co1–N4
1.953(2)
1.956(2)
1.955(2)
1.956(2)
89.93(7)
N1–Co1–N3
N1–Co1–N4
N2–Co1–N3
N2–Co1–N4
N3–Co1–N4
172.25(7)
90.25(7)
90.55(7)
172.83(8)
90.24(7)
hydrogen-bonding interactions: C12–H12A···Cg1 with d
=
=
=
=
=
C···Cg
3.943(3) Å and Є(DHA) = 144.11°; C24–H24A···Cg2 with d
3.318(3) Å and Є(DHA) = 118.43°; C21–H21A···Cg3 with d
3.788(3) Å and Є(DHA) = 171.32°; C19–H19A···Cg4 with d
3.788(5) Å and Є(DHA) = 174.26°; C25–H25A···Cg4 with d
C···Cg
C···Cg
C···Cg
C···Cg
N1–Co1–N2
[a] Symmetry codes #1: –x, –y, –z. [b] Symmetry codes #1: –x +
1, –y, –z. [c] Symmetry codes #1: –x, –y, –z. [d] Symmetry codes
#1: x, 1.5 – y, 0.5 + z. [e] Symmetry codes #2: –x + 1, –y + 2, –z
+ 1.
3.922(3) Å and Є(DHA) = 153.74° [Cg1, Cg2, Cg3, and Cg4 stand
for the centers of gravity of the rings N1(C2–C5), N2(C7–C10),
C11–C16, and C20–C25, respectively].
Zn[TCPP-Me4] (4)
In contrast to the case described above, the X-ray diffrac-
tion analysis reveals that the structure of 4 comprises neu-
tral 2D polymer layers, as shown in Figures 3 and 4. Com-
pound 4 crystallizes in the space group P21/c of the mono-
clinic system with two formula units in a cell. All crystallo-
graphically independent atoms are in general positions with
the exception of the Zn1 atom which lies on the crystallo-
graphic center of inversion. The 24-membered macrocyclic
core of the porphyrin is coplanar, and the displacement of
each atom in the equatorial mean plane is within Ϯ0.059 Å.
The six-coordinate zinc atom is located at the center of this
almost perfectly planar porphyrin macrocycle and is
bonded to four nitrogen and two oxygen atoms to construct
an octahedron (Figure 3). The Zn–N bond lengths range
from 2.030(2) to 2.046(2) Å with an average value of
2.038(2) Å, which is similar to that of 1 and comparable to
that found in the literature.[32–42] The Zn–O bond length is
2.543(2) Å, which is comparable to those found for related
species in the Cambridge Structural Database.[44–48] The
bond valence calculations show that the zinc ion has a +2
Figure 1. ORTEP drawing of 1 with 30% thermal ellipsoids. Hy-
drogen atoms are omitted for clarity.
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Change in Supramolecular Networks through In Situ Esterification of Porphyrins
oxidation state [Zn1: 2.14]. The four phenyl groups are ap- boring phenyl ring to form a C–H···π interaction. There-
proximately perpendicular to the macrocycle core; the dihe- fore, supramolecular structures can be modified through
dral angles between the macrocycle and their mean planes different ester groups.
are 64.63(9)° and 88.0(1)°, respectively. Each Zn[TCPP-
Me4] unit links to four neighboring molecules through Zn–
O bonds, which gives a condensed 2D coordination poly-
mer assembly with a herring-bone pattern (Figure 4).
Figure 3. ORTEP drawing of 4 with 30% thermal ellipsoids. Hy-
drogen atoms are omitted for clarity.
Figure 5. (a) Packing diagram of 4 with the dashed lines represent-
ing hydrogen-bonding and C–H···π interactions (the circle high-
lights the ester carbon atom that is not involved in the formation of
a C–H···π interaction). Represented interactions: C12–H12A···Cg1
with dC···C = 3.597(3) Å and Є(DHA) = 146.81°; C21–H21A···Cg2
with
g= 3.319(3) Å and Є(DHA) = 124.14°; O3···C13 (1 – x,
0.5 +Cy·,··C0g.5 – z) = 3.225(4) Å [Cg1 and Cg2 stand for the centers of
gravity of the rings N1(C2–C5) and N2(C7–C10), respectively]. (b)
Space-filling illustration of the porous crystalline architecture of 4.
As shown in Figure 5b, it is noteworthy that compound
4 exhibits a large void space of 361 Å3, that is 14% of the
unit-cell volume. There is no need to incorporate other
counteranions into compound 4, as the charges are already
balanced during the metalation and deprotonation of the
TCPP core. Therefore, no counteranions exist in the large
voids.
Figure 4. (a) Top view and (b) side view of the 2D slab of 4 (wire
representation).
There are only one hydrogen-bonding and two C–H···π
interactions among the molecules of 4. It should be pointed
out that no C–H···π interactions exist between the ester
groups (shown enclosed in a circle in Figure 5a) and the
neighboring phenyl rings, and, as a result, a 3D supra-
molecular network cannot be constructed (Figure 5a). This
is quite different from 1. Such a difference is probably re-
M[TCPP-Me4] [M = Cu (5) and Co (6)]
The X-ray structural determination reveals that com-
lated to the fact that both compounds have different ester pounds 5 and 6 feature an isolated structural motif in which
groups (ethyl and methyl for 1 and 4, respectively), and the a four-coordinate metal ion resides at the center of a saddle-
ethyl group is larger and therefore is able to reach a neigh- distorted nonplanar porphyrin macrocycle. X-ray diffrac-
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W. Chen, S. Fukuzumi
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tion analyses show that the structures of 5 and 6 consist of mation). However, no C–H···π interactions exist between
neutral M[TCPP-Me4] moieties, as shown in Figures 6 and the ester groups and the neighboring aryl rings, in contrast
S7 (Supporting Information). The four-coordinate copper to that in 4. This is probably because the methyl group is
or cobalt atom is located at the center of the porphyrin not large enough to interact with an adjacent aryl ring to
macrocycle and is bonded to four nitrogen atoms. The Cu– yield
a C–H···π interaction. For compound 5, the
N bond lengths range from 1.974(2) to 1.994(2) Å with an Cu[TCPP-Me4] moieties are interconnected together by C–
average value of 1.983(2) Å in 5, which is comparable to H···π and hydrogen-bonding interactions to form a 2D sup-
that reported.[49–59] For compound 6, the Co–N distances ramolecular network (Figure 7). For compound 6, the
are in the narrow range 1.953(2)–1.956(2) Å, which is com- Co[TCPP-Me4] molecules link to each other through more
parable to those previously documented.[60–63] The por- abundant C–H···π, π–π, and hydrogen-bonding interactions
phyrin macrocycles in 5 and 6 display a four-saddle confor- to construct a 3D supramolecular structure (see Supporting
mation, and the four pyrrole rings appreciably distort in an Information, Figure S8). The different packing motifs be-
alternant fashion, either upward and downward with re- tween 5 and 6 may result from the different metal centers
spect to the mean plane of the saddlelike porphyrin core. in 5 and 6, because different metal ions would lead to dif-
The displacement of the four pyrrole N atoms is within ferent sizes of the molecules and different distances between
Ϯ0.11 Å (in 5) and Ϯ0.15 Å (in 6) from their mean N4 the molecules.
plane. For compound 5, the dihedral angles between the
planes of the four pyrrole rings distorted in the same direc-
tion with respect to the N4 plane are 25.7(2)° and 22.4(2)°,
while these angles are 20.2(1)° and 28.8(1)° for 6. The dihe-
dral angles between the neighboring pyrrole rings are
19.7(2)°, 17.2(2)°, 14.9(1)°, and 16.6(2)° in 5 and 18.7(1)°,
22.4(1)°, 19.9(1)°, and 17.0(1)° in 6. With respect to the N4
plane, which may represent the mean plane of the porphyrin
core, the twist angles of the aryl rings are 52.04(8)°,
49.81(7)°, 69.48(8)°, and 83.90(7)° in 5 and 48.85(6)°,
80.44(6)°, 89.24(8)°, and 58.07(8)° in 6.
Figure 7. Packing diagram of 5 with the dashed lines representing
hydrogen-bonding and C–H···π interactions. Represented hydro-
gen-bonding interactions: C30–H30A···Cg1 with dC···C
3.566(3) Å and Є(DHA) = 134.42°; C50–H50A···Cg2 with d
=
=
=
=
=
=
=
=
g
C···Cg
C···Cg
3.622(4) Å and Є(DHA) = 119.85°; C3–H3A···Cg3 with d
3.825(3) Å and Є(DHA) = 115.77°; C26–H26A···Cg3 with d
3.430(3) Å and Є(DHA) = 110.17°; C22–H22A···Cg4 with d
3.344(3) Å and Є(DHA) = 108.76°; C42–H42A···Cg5 with d
3.926(3) Å and Є(DHA) = 119.72°; C17–H17A···Cg6 with d
4.020(4) Å and Є(DHA) = 131.99°; C34–H34A···Cg7 with d
C···Cg
C···Cg
C···Cg
C···Cg
C···Cg
3.734(4) Å and Є(DHA) = 149.89°; O3···C25 (x, –y, 0.5 + z) =
3.202(4) Å [Cg1, Cg2, Cg3, Cg4, Cg5, Cg6, and Cg7 stand for the
centers of gravity of the rings N1(C1–C4), N2(C6–C9), N3(C11–
C14), N4(C16–C19), C21–C26, C37–C42, and C45–C50, respec-
tively].
For the zinc-containing compounds 1 and 4, compound
1 exhibits an isolated structural feature and a 3D supra-
molecular network with the zinc ion in a four-coordination
sphere, while compound 4 is characteristic of a 2D coordi-
nation polymer and a 2D supramolecular network with the
zinc metal in a six-coordination environment. The different
coordination environments of the zinc ions, the different
structural motifs, and the different supramolecular net-
works result from different ester groups that were generated
Figure 6. (a) Face-on view (ORTEP drawing with 30% thermal el-
lipsoids) and (b) edge-on view (wire representation) of 5.
In contrast to 4, there are plenty C–H···π, π–π, and hy- by using different esterification materials. For compound 1,
drogen-bonding interactions between the molecules of 5 the ester groups come from the esterification of TCPP with
and 6, as shown in Figures 7 and S8 (Supporting Infor- ethanol; while for compound 4, TCPP is esterified with
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Change in Supramolecular Networks through In Situ Esterification of Porphyrins
methanol. Similarly, for the copper-containing compounds 7 and free-base TCPP (Table 2). This difference is attributed
2 and 5, compound 2 features a nearly perfectly planar por- to an increase in the molecular symmetry, which results
phyrin macrocycle, while compound 5 shows a four-saddle from the metalation of the free-base TCPP. By the same
distorted conformation. This difference is also caused by token, compounds 4–6 also exhibit only one Q band around
the different ester groups, as the cases of 1 and 4. Thus, 540 nm (Figure 8b). The absorption coefficients of the B
esterification plays an important role in constructing dif- bands for metalloporphyrins 1–6 are about 105 –1 cm–1,
ferent structural motifs and different supramolecular net- which is in good agreement with that found by Gouter-
works.
man.[64] The B band of free-base TCPP displays a large mo-
lar absorption coefficient (magnitude of a million), which is
over one magnitude larger than that of the esterified com-
pounds 1–8. This clearly indicates that the esterification re-
sults in a decrease in the absorption coefficient. Thus, modi-
fication through peripheral esterification can change the
electronic absorption properties of porphyrins. This enables
porphyrins to be potentially useful sensors of their sur-
rounding environments.
UV/Vis Absorption Spectroscopy
According to Gouterman’s four orbitals model,[64]
metalloporphyrins usually exhibit two types of intense ab-
sorption bands, i.e. the intense B band (Soret band) around
400 nm with an absorption coefficient (ε) of ca. 105 –1 cm–1
and the less intense Q bands between 500 and 650 nm with
an ε value of ca. 103–104 –1 cm–1. Figure 8a displays the
UV/Vis absorption spectra for compounds 1–3, 7, and free-
base TCPP. The B band and four Q bands for free-base
TCPP are observed at 416, 512, 546, 590, and 645 nm. The
B band of compounds 1–3 and 7 appears at 422 nm (ε =
Table 2. UV/Vis absorption data (CHCl3 and EtOH for 1–8 and
TCPP, respectively, 298 K).
λ(B band) [nm] (ε, –1cm–1) λ(Q band) [nm]
Zn[TCPP-Et4] (1) 422 (4.18ϫ105)
Cu[TCPP-Et4] (2) 418 (3.84ϫ105)
Ni[TCPP-Et4] (3) 417 (3.58ϫ105)
Zn[TCPP-Me4] (4) 422 (4.88ϫ105)
Cu[TCPP-Me4] (5) 418 (2.22ϫ105)
Co[TCPP-Me4] (6) 410 (1.12ϫ105)
TCPP-Et4 (7)
TCPP-Me4 (8)
TCPP
548
540
530
549
540
542
4.18ϫ105 –1 cm–1), 418 nm (ε
417 nm (ε
=
3.84ϫ105 –1 cm–1),
3.58ϫ105 –1 cm–1), and 421 nm (ε
=
=
1.48ϫ105 –1 cm–1), respectively. They are shifted to the red
by one to several nanometers relative to that of TCPP.
Compounds 1–3 only have one Q band in the range 530–
550 nm, three bands less than the nonmetalated compound
421 (1.48ϫ105)
421 (2.37ϫ105)
416 (7.27ϫ106)
516, 550, 595, 633
516, 550, 591, 654
512, 546, 590, 645
Photoluminescence
For solid-state porphyrins and their derivatives, it is well
known that they cannot display emission bands because of
concentration quenching. If, however, they were dissolved
in solution, they would usually exhibit bright emission
bands that occur in the red region of the spectrum. For this
reason, photoluminescence investigations have been carried
out in CHCl3 and ethanol solutions for 1–8 and TCPP,
respectively.
The low-temperature (77 K) phosphorescence spectra of
1–8 were measured, and the results are shown in Fig-
ures S13–S20 (Supporting Information). For compound 1,
the maximum phosphorescence emission band appears at
605 nm with a shoulder at 658 nm, upon excitation at
561 nm (Supporting Information, Figure S13). For com-
pounds 2 and 3, the maximum phosphorescence emission
bands appear at 722 nm (λex = 531 nm) and 701 nm (λex
=
568 nm), respectively. These bands are shifted to the red
relative to that of 1 (Supporting Information, Figures S14
and S15). This is probably as a result of the different metal
centers between compound 1 (zinc) and compound 2 (cop-
per) or 3 (nickel). Compound 4 has a maximum phospho-
rescence emission band at 614 nm with a shoulder at
657 nm (λex = 566 nm; Supporting Information, Fig-
ure S16), which is similar to that in 1 as could be expected
as both compounds contain zinc centers. Although both
Figure 8. UV/Vis absorption spectra measured at room tempera-
ture (CHCl3 and EtOH for 1–8 and TCPP, respectively): (a) 1–3,
7, and TCPP; (b) 4–6, 8, and TCPP. Molar absorption coefficients:
ε422nm = 4.18ϫ105 (1), ε418nm = 3.84ϫ105 (2), ε417nm = 3.58ϫ105
(3), ε422nm = 4.88ϫ105 (4), ε418nm = 2.22ϫ105 (5), ε410nm
=
1.12ϫ105 (6), ε421nm = 1.48ϫ105 (7), ε421nm = 2.37ϫ105 (8), and
ε416nm = 7.27ϫ106 –1 cm–1 (TCPP).
Eur. J. Inorg. Chem. 2009, 5494–5505
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5499

W. Chen, S. Fukuzumi
FULL PAPER
compounds 2 and 5 have the same metal center (copper),
they show largely different phosphorescence emission
bands. Compound 5 exhibits a maximum phosphorescence
emission band at 840 nm (λex = 558 nm; Supporting Infor-
mation, Figure S17), which is redshifted by 118 nm relative
to that of 2. Such a large redshift should be attributed to
the different structural motifs between 2 and 5. In compari-
son with the almost perfectly planar porphyrin macrocycle
of 2, the saddle-distorted nonplanar porphyrin macrocycle
of 5 exhibits a phosphorescence emission band with lower
energy. Since different structural motifs result from different
esterification processes, esterification processes also play an
important role in changing the phosphorescence properties.
Similarly to 5, compound 6 also displays a lower-energy
phosphorescence emission band at 855 nm (λex = 568 nm),
as shown in Figure S18 (Supporting Information). For the
nonmetalated compounds 7 and 8, they show maximum
phosphorescence emission bands at 661 nm and 692 nm by
excitation at 559 nm and 460 nm, respectively (Supporting
Information, Figures S19 and S20).
Figure 9. Emission spectra of 1–3 and 7 at room temperature.
The fluorescence emission spectra of 1–3 measured at
room temperature are shown in Figure 9. The fluorescence
spectrum of 1 shows two emission bands at 600 nm and
643 nm by excitation at 549 nm. Similarly, compound 2 dis-
plays a main emission band at 651 nm and a weaker band
at 700 nm, upon excitation at 589 nm. When excited at
374 nm, compound 3 exhibits two split emission bands at
443 nm and 461 nm, which are largely blueshifted relative
to those of 1 and 2. This difference clearly results from the
different metalation in 1–3. As for compound 4, upon exci-
tation at 558 nm, the emission spectrum also displays two
emission bands at 604 and 648 nm, which is similar to that
in the other zinc-containing compound 1 (Figure 10). Both
compounds 5 and 6 show one main band located at 676 nm
and 474 nm upon excitation at 451 nm and 367 nm, respec-
tively (Figure 10). For the two nonmetalated compounds 7
and 8, their fluorescence emission spectra show similar fea-
tures with a dominant band and a shoulder at 662 and
Figure 10. Emission spectra of 4–6 and 8 at room temperature.
713 nm (λex = 543 nm) for 7 and at 650 and 706 nm (λex
=
589 nm) for 8 (Figure 11). It should be pointed out that the
emission spectra of free-base TCPP features a main band
at 650 nm and a shoulder at 710 nm upon excitation at
589 nm, which is similar to that observed in nonmetalated
7 and 8 (Figure 11).
By using a time-correlated single photon counting tech-
nique, the fluorescence lifetimes in solution were measured
upon excitation at 421 nm, where light can be absorbed by
the porphyrin molecules. The time-resolved fluorescence de-
cay profiles for 1, 3, 4, 6–8, and TCPP are shown in Fig-
ure 12. The time decay curves were fitted as single ex-
ponentials, and the results are summarized in Table 3. The
fluorescence lifetimes of the metalated compounds 1–6 are
Figure 11. Emission spectra of 7, 8, and TCPP at room tempera-
ture.
less than 3.5 ns, which is much shorter than those of the pounds 7 and 8 are about 4 ns shorter. This decrease in the
nonmetalated compounds 7 and 8 (11.21 ns and 11.51 ns, fluorescence lifetime may be caused by the esterification of
respectively). This is ascribed to the heavy metal effect, i.e. the peripheral groups of porphyrins. The emission quantum
metalation of the porphyrin quenches the fluorescence. yields for the solution samples were determined, and the
Comparison with the lifetime of the free-base TCPP results are also presented in Table 3. The emission quantum
(15.65 ns) shows that the fluorescence lifetimes of com- yields of the metalated compounds 1–6 are obviously lower
5500
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Eur. J. Inorg. Chem. 2009, 5494–5505

Change in Supramolecular Networks through In Situ Esterification of Porphyrins
than those of the nonmetalated compounds 7 and 8 and consistent with that found for TPP compounds.[65] The ob-
the free-base TCPP, and this decrease is also ascribed to the vious difference in the electrochemical properties of 1–3
heavy metal effect.
could be related to their different metal centers, which veri-
fies that metalation could affect the electrochemical proper-
ties of porphyrins. For compound 4, three quasi-reversible
waves with E1/2 = 0.35, –1.35, and –1.85 V are found in the
cyclic voltammograms. The HOMO–LUMO gap for 4 is
1.70 V, smaller than that of 1, which is also a zinc-contain-
ing compound. The lower oxidation potential and the
higher reduction potential of 4 relative to those of 1 may
result from the different structural motifs of 1 and 4: com-
pound 4 has a 2D coordination polymer structure, whereas
compound 1 is monomeric as indicated by an isolated struc-
tural feature in the crystal (vide supra). Such a structural
difference between 1 and 4 is also caused by their different
ester groups as discussed in the crystal structure section.
Thus, esterification also plays an important role in changing
the electrochemical properties.
Figure 12. Time-resolved fluorescence decay profiles for 1, 3, 4, 6–
8, and TCPP.
Table 4. Half-wave potentials (E1/2, [V] vs. Ag/AgNO3) and the elec-
trochemical HOMO–LUMO gap [V].
Table 3. Emission quantum yields Φ and fluorescence lifetimes τ.
E1/2 [V]
HOMO–LUMO gap [V]
Φ
τ [ns]
Φ
τ [ns]
1
2
3
4
5
6
7
8
0.87, 0.50, –1.69
0.70, –1.60
0.79, –1.62
0.35, –1.35, –1.85
0.66, –1.64
1.14, 0.86, –1.23
0.73, 0.52, –1.50
0.73, 0.50, –1.46
2.19
2.30
2.41
1.70
2.30
2.09
2.02
1.96
1
2
3
4
5
0.012
0
0.014
0.027
0
3.15
0
2.06
0.553
0
6
0
1.54
7
0.056
0.046
0.044
11.21
11.51
15.65
8
TCPP
Electrochemical Studies
The cyclic voltammogram of 5 is characterized by two
quasi-reversible redox couples with E1/2 = 0.66 V and
–1.64 V. The first oxidation half-wave potential for 2 and
5 are 0.70 V and 0.66 V, respectively, which suggests that
compound 5 can be oxidized more easily than 2. This ease
in oxidation of 5 is in good agreement with the fact that it
has a nonplanar conformation, while compound 2 adopts
a planar motif; this is in agreement with that found in the
literature.[66] The HOMO–LUMO gap for 5 is 2.30 V, in
accordance with that of 2. For the cobalt-containing com-
pound 6, the slow sweep cyclic voltammogram exhibits
three quasi-reversible waves with E1/2 values of 1.14, 0.86,
and –1.23 V and a HOMO–LUMO gap of 2.09 V. The cy-
clic voltammogram of 7 is characteristic of three quasi-re-
versible redox couples with E1/2 = 0.73, 0.52, and –1.50 V.
The HOMO–LUMO gap for 7 is 2.02 V, obviously smaller
than those of 1–3, which have similar structural motifs to
7. The difference in the electrochemical properties between
the nonmetalated compound 7 and the metalloporphyrins
1–3 is caused by the metalation effect. Similar to that of
7, the cyclic voltammogram of 8 also features three quasi-
reversible redox couples with E1/2 = 0.73, 0.50, –1.46 V and
a HOMO–LUMO gap of 1.96 V.
According to Kadish et al.,[65] the vital factors that
mostly affect metalloporphyrin redox potentials can be
grouped into (a) the properties of the supporting electrolyte
and solvent and (b) the properties of porphyrin itself. The
latter set includes the type and number of axial ligands, the
type and oxidation state of the metal center, and the type
and planarity of the macroring. Depending on different
substituents, the redox potentials can be varied up to 1.0 V
or more.
Cyclic voltammograms of 1–8 were recorded in benzoni-
trile at room temperature in the presence of TBAPF6 (0.1 )
to investigate their redox properties (Supporting Infor-
mation, Figure S21 and Table 4). As shown in Figure S21,
slow sweep cyclic voltammetry on 1 exhibits three quasi-
reversible waves with E1/2 = 0.87, 0.50, and –1.69 V, and the
electrochemical HOMO–LUMO gap is 2.19 V, which is
close to the value for ZnTPP (2.15 V).[65] The cyclic voltam-
mogram of 2 features two quasi-reversible waves with E1/2
=
0.70 V and –1.60 V, and the accompanying electrochemical
HOMO–LUMO gap is 2.30 V, which is comparable to that
found for CuTPP (2.27 V).[65] The slow scan cyclic voltam-
mogram of 3 displays two reversible redox couples with
E1/2 values of 0.79 V and –1.62 V. Compound 3 has the
largest HOMO–LUMO gap of 2.41 V (2.30 V for
NiTPP[65]) among compounds 1–3 with similar molecular
structures. The electrochemical HOMO–LUMO gap in-
Conclusions
By using a solvothermal in situ esterification method, we
creases in the order: 1 (Zn) Ͻ 2 (Cu) Ͻ 3 (Ni), which is have successfully synthesized eight porphyrin compounds
Eur. J. Inorg. Chem. 2009, 5494–5505
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W. Chen, S. Fukuzumi
FULL PAPER
found C 69.25, H 4.65, N 5.87. FTIR (KBr): ν = 2975 (w), 2935
˜
with the aim of preparing a series of porphyrins with dif-
ferent supramolecular networks and properties. These com-
pounds have been well characterized by X-ray structural
analysis, MALDI-TOF MS spectrometry, FTIR, UV/Vis,
fluorescence, and phosphorescence spectroscopy, quantum
yields, luminescence lifetimes, and cyclic voltammetry. The
esterification of porphyrins under solvothermal conditions
can easily control the formation of various supramolecular
networks. Future research in our laboratory will aim at syn-
thesizing other porphyrin supramolecules, to gain a deeper
insight into the synthetic methodology, as well as the rela-
tionship between the synthesis and the crystal structures
and properties.
(w), 2900 (w), 2362 (w), 1933 (w), 1829 (w), 1720 (vs), 1605 (s),
1560 (m), 1460 (w), 1400 (m), 1366 (m), 1271 (vs), 1172 (m), 1097
(s), 1022 (m), 997 (s), 863 (w), 803 (m), 758 (m), 738 (w) and 703(w)
cm–1. MALDI-TOF MS [CHCl3, matrix CHCA (α-cyano-4-hy-
droxycinnamic acid)]: m/z calcd. for C56H44N4O8Zn 964.25; found
963.97 (Supporting Information, Figure S1).
Cu[TCPP-Et4] (2): This compound was prepared by the procedure
described for 1 by using CuCl2·2H2O (0.1 mmol, 17 mg) instead of
ZnSO4·H2O. Yield: 80 mg (83%, based on copper). C56H44CuN4O8
(963.26): calcd. C 69.67, H 4.56, N 5.81; found C 69.98, H 4.77, N
5.89. FTIR (KBr): ν = 2973 (w), 2938 (w), 2897 (w), 2361 (w), 1829
˜
(w), 1720 (vs), 1655 (w), 1605 (s), 1560 (w), 1510 (w), 1461 (w),
1401 (m), 1366 (w), 1346 (m), 1271 (vs), 1206 (w), 1172 (m), 1095
(s), 1022 (m), 997 (vs), 867 (w), 803 (m), 763 (s), 723 (w) and 669
(m) cm–1. MALDI-TOF MS (CHCl3, matrix CHCA): m/z calcd.
for C56H44CuN4O8 963.26; found 963.45.
Ni[TCPP-Et4] (3): Compound 3 was prepared by the procedure
described for 1 by using NiCl2 (0.1 mmol, 13 mg) instead of
ZnSO4·H2O. Yield: 72 mg (75%, based on nickel). C56H44N4NiO8
(958.25): calcd. C 70.03, H 4.59, N 5.84; found C 69.82, H 4.72, N
Experimental Section
Measurements: Elemental analyses were carried out with an Ele-
mentar Vario EL III microanalyzer. The infrared spectra were re-
corded on a Thermo Nicolet NEXUS 870 FTIR spectrophotome-
ter over the frequency range 4000–400 cm–1 by using KBr pellets.
The UV/Vis absorption spectra were recorded at room temperature
on a computer-controlled Hewlett Packard 89090A UV/Vis spec-
trometer with a wavelength range of 190–1100 nm. Matrix-assisted
laser desorption/ionization (MALDI) time-of-flight (TOF) mass
spectra were measured on a Kratos Compact MALDI I (Shim-
adzu). The phosphorescence and the fluorescence studies were con-
ducted on a Shimadzu RF-530XPC fluorescence spectroscopy in-
strument at 77 K and at room temperature, respectively. Measure-
ments of the emission quantum yields of the solution samples were
carried out on a Hamamatsu C9920–0X(PMA-12) U6039–05 fluo-
rescence spectrofluorometer with an integrating sphere adapted to
a right-angle configuration at room temperature and involve the
determination of the diffuse reflectance spectra of the samples. The
measured results were corrected for the detector response as a func-
tion of wavelength. Fluorescence lifetime measurements were con-
ducted by using a Photon Technology International GL-3300 nitro-
gen laser with a Photon Technology International GL-302 dye laser
and a nitrogen laser/pumped dye laser system equipped with a four-
channel digital delay/pulse generator (Standard Research System
Inc., model DG535) and a motor driver (Photon Technology Inter-
national, model MD-5020). The excitation wavelength was set at
421 nm with use of a POPOP chromophore. Cyclic voltammetry
was performed at 298 K with a BAS 100 W electrochemical ana-
lyzer in deaerated benzonitrile containing 0.1  TBAPF6 (tetra-n-
butylammonium hexafluorophosphate) as a supporting electrolyte.
A conventional three-electrode cell was used with a platinum work-
ing electrode and a platinum wire as a counter electrode. The mea-
sured potentials were recorded with respect to the Ag/AgNO3 sys-
tem (1.0ϫ10–2 ). All electrochemical measurements were carried
out under an atmospheric pressure of argon.
5.89. FTIR (KBr): ν = 2977 (w), 2938 (w), 2896 (w), 2361 (w), 1829
˜
(w), 1719 (vs), 1655 (w), 1605 (s), 1560 (w), 1505 (w), 1456 (w),
1400 (m), 1351 (m), 1271 (vs), 1207 (w), 1172 (m), 1097 (s), 997 (s),
863 (w), 828 (w), 803 (m), 763 (s), 709 (w) and 669-
(m) cm–1. MALDI-TOF MS (CHCl3, matrix CHCA): m/z calcd.
for C56H44N4NiO8 958.25; found 957.66.
Zn[TCPP-Me4] (4): This compound was prepared by the procedure
described for 1 by using methanol instead of ethanol. Yield: 65 mg
(72%, based on zinc). C52H36N4O8Zn (908.18): calcd. C 68.55, H
3.96, N 6.15; found C 68.30, H 4.22, N 6.21. FTIR (KBr): ν =
˜
3438 (m), 2970 (m), 2875 (m), 2820 (w), 2661 (m), 2531 (m), 1680
(vs), 1605 (s), 1565 (m), 1505 (w), 1425 (s), 1316 (s), 1291 (s), 1182
(m), 1126 (w), 1072 (w), 1022 (w), 997 (s), 867 (m), 798 (s), 768
(m), 723 (w) and 668 (m) cm–1. MALDI-TOF MS (CHCl3, matrix
CHCA): m/z calcd. for C52H36N4O8Zn 908.18; found 907.67.
Cu[TCPP-Me4] (5): Compound 5 was prepared by the procedure
described for 1 by using CuCl2·2H2O (0.1 mmol, 17 mg) and meth-
anol instead of ZnSO4·H2O and ethanol. Yield: 69 mg (76%, based
on copper). C52H36CuN4O8 (907.19): calcd. C 68.69, H 3.96, N
6.16; found C 68.90, H 4.08, N 6.15. FTIR (KBr): ν = 2950 (w),
˜
2840 (w), 2362 (w), 2337 (w), 1929 (w), 1819 (w), 1724 (vs), 1605
(s), 1565 (w), 1435 (s), 1400 (m), 1346 (m), 1271 (vs), 1206 (m),
1176 (w), 1112 (s), 997 (s), 863 (w), 822 (m), 798 (m), 763 (s), 718
(m) cm–1. MALDI-TOF MS (CHCl3, matrix CHCA): m/z calcd.
for C52H36CuN4O8 907.19; found 906.39.
Co[TCPP-Me4] (6): This compound was prepared by the procedure
described for 1 by using CoCl2·6H2O (0.1 mmol, 23.8 mg) and
methanol instead of ZnSO4·H2O and ethanol. Yield: 63 mg (70%,
based on cobalt). C52H36CoN4O8 (903.19): calcd. C 69.04, H 4.00,
N 6.20; found C 68.96, H 4.15, N 6.23. FTIR (KBr): ν = 3423 (m),
˜
2950 (w), 2840 (w), 2361 (w), 2337 (w), 1719 (vs), 1605 (s), 1565
(w), 1435 (m), 1400 (w), 1351 (m), 1276 (vs), 1177 (w), 1112 (s),
1002 (s), 868 (w), 823 (m), 798 (m), 762 (s), 719 (m) cm–1. MALDI-
TOF MS (CHCl3, matrix CHCA): m/z calcd. for C52H36CoN4O8
903.19; found 903.00.
Syntheses: All reactants of A. R. grade were obtained commercially
and used without further purification.
Zn[TCPP-Et4] (1): This compound was prepared by mixing
ZnSO4·H2O (0.1 mmol, 17.9 mg), TCPP (0.1 mmol, 79 mg), and
ethanol (10 mL) in a 23 mL Teflon-lined stainless steel autoclave
and by heating the mixture at 453 K for 1 d. After the mixture is
slowly cooled to room temperature at 6 K/h, purple crystals suit-
able for X-ray analysis were obtained. Yield: 76 mg (79%, based
on zinc). C56H44N4O8Zn (964.25): calcd. C 69.54, H 4.55, N 5.80;
TCPP-Et4 (7): This compound was prepared by the procedure de-
scribed for 1 by using MoCl3 (0.1 mmol, 20.2 mg) instead of
ZnSO4·H2O, and the reaction time was only 1 h. Yield: 78 mg
(87%). C56H46N4O8 (902.33): calcd. C 74.42, H 5.10, N 6.20; found
C 74.04, H 5.17, N 6.08. FTIR (KBr): ν = 3319 (w), 2974 (w), 2935
˜
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Change in Supramolecular Networks through In Situ Esterification of Porphyrins
(w), 2900 (w), 2362 (w), 1717 (vs), 1654 (w), 1607 (s), 1582 (w),
TOF MS (CHCl3, matrix CHCA): m/z calcd. for TCPP-Me4
1559 (w), 1538 (w), 1508 (w), 1472 (w), 1403 (m), 1365 (w), 1306 C52H38N4O8 846.27; found 845.87.
(w), 1271 (vs), 1214 (w), 1173 (w), 1097 (s), 1023 (m), 995 (w), 966
(m), 865 (w), 806 (w), 765 (m), 742 (w), 668 (m) cm–1. MALDI-
TOF MS (CHCl3, matrix CHCA): m/z calcd. for C56H46N4O8
902.33; found 901.57.
X-ray Crystallographic Studies: The intensity data sets were col-
lected on Rigaku AFC-8 X-ray diffractometers with graphite mo-
nochromated Mo-Kα radiation (λ = 0.71073 Å) using a ω scan tech-
nique. CrystalClear software was used for data reduction and em-
pirical absorption corrections.[67,68a] The structures were solved by
the direct methods using the Siemens SHELXTLTM Version 5
TCPP-Me4·H2O (8): Compound 8 was prepared by the procedure
described for 1 by using MoCl3 (0.1 mmol, 20.2 mg) and methanol
instead of ZnSO4·H2O and ethanol, and the reaction time was only
1 h. Yield: 77 mg (91%). C52H40N4O9 (846.27): calcd. C 72.21, H package of crystallographic software.[68b] The difference Fourier
4.62, N 6.47; found C 72.58, H 4.35, N 6.43. FTIR (KBr): ν =
maps based on these atomic positions yield the other non-hydrogen
˜
3428 (m), 3320 (w), 2945 (w), 2841 (w), 2361 (w), 2341 (w), 1929 atoms. The hydrogen atom positions were generated theoretically,
(w), 1817 (w), 1725 (vs), 1605 (s), 1561 (w), 1435 (m), 1401 (m), allowed to ride on their respective parent atoms and included in
1350 (w), 1275 (vs), 1211 (w), 1191 (w), 1112 (s), 1022 (m), 992 (w),
the structure factor calculations with assigned isotropic thermal
967 (m), 866 (w), 823 (w), 803 (m), 759 (m), 738 (w) cm–1. MALDI- parameters. The structures were refined by using a full-matrix least-
Table 5. Crystal parameters of compounds 1–8.
1
2
3
4
Formula
Fw
C56H44N4O8Zn
966.34
C56H44CuN4O8
964.50
C56H44N4NiO8
959.64
C52H36N4O8Zn
910.22
Color
Crystal size [mm]
Crystal system
Space group
purple
dark red
0.48ϫ0.45ϫ0.44
monoclinic
P21/c
dark red
0.48ϫ0.18ϫ0.15
monoclinic
P21/c
red
0.25ϫ0.20ϫ0.13
monoclinic
P21/c
0.42ϫ0.22ϫ0.10
monoclinic
P21/c
a [Å]
b [Å]
c [Å]
14.434(6)
8.417(3)
21.357(6)
120.34(2)
2239(1)
9.218(4)
10.792(3)
23.945(7)
111.65(1)
2214(1)
9.205(3)
10.780(4)
23.792(7)
111.68(1)
2194(1)
13.716(3)
9.004(2)
21.062(2)
92.590(4)
2598.4(9)
2
β [°]
V [Å3]
Z
2
2
2
2θmax [°]
Reflections collected
50
14163
50
14019
50
13721
50
16125
Independent, observed reflections (Rint
)
3936, 3449 (0.0420)
1.433
0.614
3885, 2519 (0.0399)
1.447
0.559
3751, 3345 (0.0357)
1.453
0.509
4487, 2105 (0.0486)
1.163
0.525
dcalcd. [g/cm3]
µ [mm–1]
T [K]
F(000)
123.15
1004
123.15
1002
123.15
1000
123.15
940
R1, wR2
S
0.0623, 0.1671
1.016
0.0656, 0.1758
1.047
0.0578, 0.1530
1.039
0.0692, 0.1809
1.007
Largest, mean ∆ (σ)
0.001, 0
0.379, –0.506
0, 0
1.574, –0.681
0, 0
0.767, –0.746
0, 0
0.944, –0.309
∆ρ(max, min) [e/Å3]
5
6
7
8
Formula
Fw
C52H36CuN4O8
908.40
C52H36CoN4O8
903.78
C56H46N4O8
902.97
C52H40N4O9
864.88
Color
Crystal size [mm]
Crystal system
Space group
red
purple
red
red
0.25 0.10 0.08
monoclinic
P2/c
0.30 0.22 0.20
monoclinic
P2/c
0.48 0.35 0.32
monoclinic
P21/c
0.12 0.11 0.06
monoclinic
P21/c
a [Å]
b [Å]
c [Å]
20.357(3)
8.900(4)
30.161(6)
129.22(1)
4233(2)
20.137(5)
9.150(2)
29.857(5)
129.28(1)
4259(2)
9.040(2)
10.837(2)
23.886(5)
110.678(7)
2189.3(8)
2
8.509(3)
10.786(1)
22.252(3)
102.258(9)
1995.7(8)
2
β [°]
V [Å3]
Z
4
4
2θmax [°]
Reflections collected
50
25819
50
25672
50
13187
50
12029
Independent, observed reflections (Rint
)
7279, 3448 (0.1234)
1.425
0.580
7136, 4956 (0.0398)
1.410
0.467
3813, 3337 (0.0579)
1.370
0.092
3415, 1378 (0.1416)
1.439
0.100
dcalcd. [g/cm3]
µ [mm–1]
T [K]
F(000)
123.15
1876
123.15
1868
123.15
948
123.15
904
R1, wR2
S
0.0845, 0.1104
1.012
0.0699, 0.1756
1.051
0.0518, 0.1475
1.036
0.1043, 0.2234
1.021
Largest, mean ∆ (σ)
0.001, 0
0.529, –0.399
0.001, 0
0.653, –0.414
0, 0
0.449, –0.347
0.002, 0
0.343, –0.460
∆ρ(max, min) [e/Å3]
Eur. J. Inorg. Chem. 2009, 5494–5505
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5503

W. Chen, S. Fukuzumi
FULL PAPER
squares refinement on F2. All atoms except for hydrogen atoms
were refined anisotropically (Table 5). CCDC-727779, -727780,
-727781, -727782, -727783, -727784, -727785, -727786 for com-
pounds 1–8, respectively, contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
dell, D. Gust, C. R. Timmel, P. J. Hore, Nature 2008, 453, 387–
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Supporting Information (see footnote on the first page of this arti-
cle): IR spectra, MALDI-TOF MS spectra, phosphorescence spec-
tra, and some structural figures for this article are presented.
Acknowledgments
This work was supported by the Ministry of Education, Culture,
Sports, Science and Technology with a Global COE program, “the
Global Education and Research Center for Bio-Environmental
Chemistry”, and a Grant-in-Aid (No. 19205019).
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Published Online: November 17, 2009
Eur. J. Inorg. Chem. 2009, 5494–5505
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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5505