Argentivorous molecules bearing two aromatic side-arms: Ag+-π and CH-π interactions in the solid state and in solution

Article abstract of DOI:10.1021/ic302511e

Seven double-armed cyclens bearing two aromatic side-arms, at the 1- and 7-positions of the cyclens, were prepared via three steps from dimethyl 2,2′-iminodiacetate. The X-ray structures of the Ag⁺ complexes and Ag⁺-ion-induced ¹H NMR spectral changes suggest that the two aromatic side-arms cover the Ag⁺ ions incorporated in the ligand cavities, as if the aromatic ring petals catch the Ag ⁺ ions in the way a real insectivorous plant (Venus flytrap) catches insects, using two leaves. It is also reported that the CH-π interactions between the aromatic side-arms, as well as the Ag⁺-π interactions, are crucial for double- and tetra-armed cyclens to work as argentivorous molecules.

Full text of DOI:10.1021/ic302511e

Article
pubs.acs.org/IC
Argentivorous Molecules Bearing Two Aromatic Side-Arms: Ag+−π
and CH−π Interactions in the Solid State and in Solution
Yoichi Habata,*,†,‡ Aya Taniguchi,† Mari Ikeda,†,‡ Takao Hiraoka,† Noriko Matsuyama,† Sakiko Otsuka,†
and Shunsuke Kuwahara†,‡
†Department of Chemistry, Faculty of Science, and ‡Research Center for Materials with Integrated Properties, Toho University, 2-2-1
Miyama, Funabashi, Chiba 274-8510, Japan
S
* Supporting Information
ABSTRACT: Seven double-armed cyclens bearing two
aromatic side-arms, at the 1- and 7-positions of the cyclens,
were prepared via three steps from dimethyl 2,2′-iminodiace-
tate. The X-ray structures of the Ag+ complexes and Ag+-ion-
induced 1H NMR spectral changes suggest that the two
aromatic side-arms cover the Ag+ ions incorporated in the
ligand cavities, as if the aromatic ring “petals” catch the Ag+
ions in the way a real insectivorous plant (Venus flytrap)
catches insects, using two leaves. It is also reported that the
CH−π interactions between the aromatic side-arms, as well as
the Ag+−π interactions, are crucial for double- and tetra-armed
cyclens to work as argentivorous molecules.
INTRODUCTION
■
Increasing attention has been focused on metal-cation−π1 and
CH−π2a−e interactions. It is well known that weak molecular
forces such as cation−π, CH−π, hydrogen-bonding, and
dipole−dipole interactions are important for controlling the
shapes of compounds and play a vital role in various specific
phenomena in chemistry and biochemistry.2d Recently, we
reported that tetra-armed cyclens with aromatic side-arms
behave like an insectivorous plant (Venus flytrap) when they
form complexes with Ag+ ions; that is, the aromatic side-arms
cover the Ag+ ions incorporated in the ligand cavities by Ag+−π
interactions,3 and no conformational changes are observed
when other metal cations are added in organic solvents or in
water.4a,b Several groups have reported the X-ray structures of
Co2+, Ni2+, Cu2+, and Zn2+ complexes with tetra-armed
Figure 1. Double-armed cyclens.
cyclens.5 Aromatic side-arms in the complexes with armed
cyclens, however, never cover the metal ions incorporated in
the cyclen unit. We therefore called the tetra-armed cyclens
AgCF3SO3 complexes were prepared using these new double-
armed cyclens.
“argentivorous molecules”.6
The Venus flytrap uses two leaves to trap insects, so we
prepared armed cyclens bearing two aromatic side-arms, at the
1- and 7-positions of the cyclen, to see if the armed cyclens
behave like flytraps. Here we report that both Ag+−π and
CH−π interactions are important for tetra-armed cyclens and
double-armed cyclens to act as argentivorous molecules.
To compare the electron densities on the aromatic ring
components we used, electrostatic potentials were calculated
using the HF/6-31G(*) method.8 The electrostatic potential is
defined as the energy of interaction of a positive point charge
with the nuclei and electrons of a molecule, and the value of the
electrostatic potential correlates with the electron densities on
the aromatic rings. Figure 2 shows the electrostatic potential
maps of the side-arm components of 1a−7a.9 Toluene (b) has
the highest electrostatic potential of the benzene derivatives
RESULTS AND DISCUSSION
■
Double-armed cyclens (1a−7a in Figure 1) bearing two
aromatic rings, at the 1- and 7-positions of the cyclen, were
prepared via two steps from 1,4,7,10-tetraazacyclododecane-
2,6-dione (see scheme in the Supporting Information).7
Received: November 16, 2012
Published: February 13, 2013
© 2013 American Chemical Society
2542
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
Figure 2. Electrostatic potential maps of (a) 1,3-difluoro-4-
methylbenzene, (b) toluene, (c) 1-methyl-4-phenoxybenzene, (d) 4-
methyl-N,N-dimethylaniline, (e) 1-methylnaphthalene, (f) 1-methyl-
anthracene, and (g) 1-methylpyrene.
(a−d in Figure 2). The electrostatic potentials of 1-
methylnaphthalene (e), 1-methylanthracene (f), and 1-methyl-
pyrene (g) are higher than those of the substituted benzenes
(a−d), and the areas with high electrostatic potentials are larger
than those of the benzenes. We therefore expected that
significant intramolecular Ag+−π interactions would be
observed in the double-armed cyclens with toluene (2a), 1-
methylnaphthalene (5a), 1-methylanthracene (6a), and 1-
methylpyrene (7a) as side-arms.
−
Figure 4. ORTEP diagram of the 4a/AgCF3SO3 complex. CF3SO3
and solvent are omitted.
this complex, the C11−Ag1 distance is shorter than the C30−
Ag1 distance. Interestingly, intramolecular CH−π interactions
between the aromatic rings are also observed in the 4a/
AgCF3SO3 complex. The H20−benzene plane (C35 to C40),
H19−benzene plane (C35 to C40), H30−benzene plane (C16
to C21), and H31−benzene plane (C16 to C21) distances are
2.764, 2.791, 2.939, and 3.132 Å, respectively. The distances are
comparable with typical CH−π distances in aromatic rings.2a,d
On the other hand, in the 5a/AgCF3SO3 and 6a/AgCF3SO3
(Figure 5a−d) complexes, two side-arms cover the Ag+ ions
incorporated in the ligand cavities as if the two aromatic ring
“petals” caught the Ag+ ions in the way an insectivorous plant
(Venus flytrap) catches insects, using two leaves. The C14−
Ag1 distance in the 5a/AgCF3SO3 complex and the C12−Ag1
and C27−Ag1 distances in the 6a/AgCF3SO3 complex are
2.821, 2.753, and 2.863 Å, respectively. In these complexes, the
Ag+−π bond distances are shorter than those of the tetra-armed
cyclens.
Figure 3 shows the X-ray structure of the 2a/AgCF3SO3
complex (see also Figure S4 in the SI for the X-ray structures of
The conformation of the pyrene side-arms in the 7a/
AgCF3SO3 complex (Figure 6) is slightly different from those
of the side-arms in the 5a/AgCF3SO3 and 6a/AgCF3SO3
complexes, although the two side-arms in the ligand cover
the Ag+ ion incorporated in the ligand cavity. The C4−Ag1,
C5−Ag1, C53−Ag1, and C55−Ag1 distances are 2.633, 2.996,
3.113, and 3.387 Å, respectively. In the complex, the C4−Ag1
and C5−Ag1 distances are shorter than the C53−Ag1 and
C55−Ag1 distances. The dihedral angle between the two
pyrene planes is ca. 78°, whereas the dihedral angles between
the two aromatic ring-planes in the 5a/AgCF3SO3 and 6a/
AgCF3SO3 complexes are ca. 30°. As shown in Figure 6a and b,
the H51−pyrene-plane and H61−pyrene-plane distances are
2.424 and 2.815 Å, respectively. These bond distances indicate
CH−π interactions between two pyrenes.
In contrast, no side-arms cover the metal cations
incorporated in the ligand cavities in the 6a/HgCl2 and 7a/
Cu(CF3SO3)2 complexes (Figure 7). These X-ray structures
suggest that (i) the aromatic rings that have higher electron
densities, such as naphthalene, anthracene, and pyrene, cover
the Ag+ ions by Ag+−π interactions, (ii) the side-arms cover the
Ag+ ions using Ag+−π and CH−π interactions only when
Figure 3. ORTEP diagram of the 2a/AgCF3SO3 complex. Hydrogen
atoms are omitted.
the 1a/AgCF3SO3 and 3a/AgCF3SO3 complexes). In the 2a/
AgCF3SO3 complex, the Ag+ ion is coordinated by the four N
atoms of the cyclen. Contrary to our expectations, the Ag+ ion
incorporated in the cyclen ring is not covered by the
intramolecularly linked side-arms, but is covered by an aromatic
side-arm of the nearest-neighbor molecule, resulting in the
formation of the one-dimensional polymeric chain structure.
The C13−Ag1 and C14−Ag1 distances are 2.608 and 2.577 Å,
respectively.
In contrast, the side-arms in 4a, with triphenylamino groups,
cover the Ag+ ions in the ligand cavities (Figure 4). We
confirmed Ag+−π interactions between the aromatic side-arms
and the Ag+ ions because the C11−Ag1 and C30−Ag1
distances are 2.666 and 3.390 Å, respectively (in tetra-armed
cyclens, typical C−Ag distance range is 3.272−3.344 Å4a). In
2543
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
Figure 5. ORTEP diagrams of 5a/AgCF3SO3 [(a) top and (b) side views] and 6a/AgCF3SO3 [(c) top and (d) side views] complexes. Hydrogen
−
atoms and CF3SO3 are omitted.
ppm, than the corresponding signals (Hg, Hh, and Hi protons)
of free 7a, respectively, upon addition of 1.0 equiv of Ag+ ions.
In contrast, in 1H NMR titration experiments using 1a, 2a, and
3a, no higher-field shifts of the aromatic protons were observed
(see Figure S5 in the SI). These results indicate that the Hg, Hh,
and Hi protons are located in the shielding area in another
pyrene ring. In the X-ray structure of the 7a/AgCF3SO3
complex (Figure 6), the H61, H53, and H51 hydrogens
corresponding to the Hg, Hh, and Hi protons are located in the
shielding area of another pyrene ring. Both the 1H NMR and X-
ray data therefore strongly support the suggestion that the
structure of the 7a/AgCF3SO3 complex in solution is similar to
the solid-state structure.
To visualize the Ag+−π interactions, the isosurfaces of the
LUMO and HOMO of the Ag+ complexes were calculated
using the B3LYP/3-21G(*) theoretical level.8 Figure 9 shows
the LUMO (mesh) and HOMOs (solid) of the X-ray structures
of the 4a/Ag+−7a/Ag+ complexes. In all cases, the LUMO of
−
the Ag+ ion is distorted by interaction with the HOMOs of the
Figure 6. ORTEP diagrams of 7a/AgCF3SO3. CF3SO3 is omitted.
aromatic side-arms. These graphics clearly support Ag+−π
interactions between the Ag+ ion and the aromatic side-arms.
substituted benzenes that can participate in CH−π interactions
between the side-arms are introduced, and (iii) when pyrene is
used as the side-arms, both Ag+−π and CH−π interactions are
observed. We previously reported that tetra-armed cyclens with
four 4-nitrobenzenes, which have very low electron densities on
the benzenes, act as argentivorous molecules. These findings
suggest that CH−π interactions, as well as Ag+−π interactions,
play a crucial role in the behavior of argentivorous molecules.3
To determine the structures of the complexes in solution,
In conclusion, we demonstrated that double-armed cyclens
bearing two aromatic side-arms with high electron densities
behave like an insectivorous plant (Venus flytrap) by Ag+−π
interactions. It was also shown that CH−π interactions between
aromatic side-arms, as well as the Ag+−π interactions, are
crucial for double- and tetra-armed cyclens to work as
argentivorous molecules. Applications of double-armed cyclens
bearing chromophores (anthracene and pyrene) as metal-ion
sensors are now in progress.
1
Ag+-ion-induced H NMR spectral changes were examined. As
shown in Figure 8, upon addition of AgCF3SO3 (below 1.0
equiv), two sets of signals appeared (one for free 7a and the
second for its complex, primed), reflecting a slow-exchanging
process. The complex signals (Hg′, Hh′, and Hi′ protons in
Figure 7) appear at higher field, ca. −0.12, −0.49, and −0.16
EXPERIMENTAL SECTION
■
General Information. Melting points were obtained with a Mel-
Temp capillary apparatus and were not corrected. FAB mass spectra
were obtained using a JEOL 600 H mass spectrometer. 1H NMR
spectra were measured in CDCl3 on a JEOL ECP400 (400 MHz)
2544
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
Figure 7. ORTEP diagrams of 7a/Cu(CF3SO3)2 (a) and 6a/HgCl2 (b).
Figure 9. LUMOs and HOMOs calculated by the DFT methods
[B3LYP/3-21G(*)] using the X-ray structures of the Ag+ complexes
with 4a−7a (isosurface value is 0.032 au). 4a/Ag+ complex,
LUMO[+1] (mesh) and HOMO[−10], HOMO[−11],
HOMO[−13], HOMO[−15] (solid); 5a/Ag+ complex, LUMO[+4]
(mesh) and HOMO[−3] (solid); 6a/Ag+ complex, LUMO[+4]
(mesh) and HOMO[−1] (solid); 7a/Ag+ complex, LUMO[+5]
(mesh) and HOMO[−2], HOMO[−6] (solid).
Figure 8. Ag+-ion-induced 1H NMR spectral changes of 7a (in
CD2Cl2/CD3OD). The positions of the Hg, Hh, and Hi protons were
assigned using ROESY, COSY, and 1D NOE NMR (Figure S6 in the
SI).
mmol) and 3,5-difluorobenzaldehyde (35.2 mmol) in dry 1,2-
dichloroethane (100 mL) at room temperature for 1 day under an
argon atmosphere (1 MP), NaBH(OAc)3 (35.1 mmol) was added and
the mixture was stirred for 1 day at room temperature. Saturated
aqueous NaHCO3 was added, and the aqueous layer was extracted
with chloroform three times. The combined organic layer was washed
with water, dried over Na2SO4, and concentrated. The residual solid
was recrystallized from acetonitrile to give 1b in 93% yield. Mp:
138.4−139.2 °C. 1H NMR (CDCl3): δ 6.97−6.91 (m, 2H), 6.93−6.85
(m, 4H), 6.82−6.74 (m, 2H), 3.89 (s, 2H), 3.69 (s, 2H), 3.30 (q, J =
5.6 Hz, 4H), 3.27 (s, 4H), 2.62 (t, J = 5.6 Hz, 4H). FAB-MS (m/z)
(matrix: DTT/TG = 1:2): 453 ([M + 1]+, 100%). Anal. Calcd for
C22H24N4O2F4: C, 58.40; H, 5.35; N, 12.38. Found: C, 58.35; H, 5.39;
N, 12.26.
spectrometer. Cold ESI-mass spectra were recorded on a JEOL JMS-
T100CS mass spectrometer. Cyclen was purchased from Macrocyclics.
All reagents were standard analytical grade and were without further
purification.
Preparation of 1,4,7,10-Tetraazacyclododecane-2,6-dione.
1,4,7,10-Tetraazacyclododecane-2,6-dione was prepared according to
the procedure described in the literature. Yield: 32%. Mp: 168.0−169.0
(dec). 1H NMR (D2O): δ 3.64 (t, J = 5.5 Hz, 4H), 3.61 (s, 4H), 2.99
(t, J = 5.5 Hz, 4H). FAB-MS (m/z) (matrix: DTT/TG = 1:2): 201
([M + 1]+, 100%).
General Procedures for the Reaction of Cyclen-dione with
Aromatic Aldehydes. After stirring a mixture of cyclen-dione (10.0
2545
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
Table 1. Crystal Data of Metal Complexes
1a/AgCF3SO3
2a/AgCF3SO3
3a/AgCF3SO3
4a/AgCF3SO3
formula
C23H28AgF7N4O3S
681.42
C23H32AgF3N4O3S
609.46
C70H80Ag2F6N8O10S2
1587.28
C48H54AgF3N6O4S
975.90
M
T/K
298
298
90
173
cryst syst
monoclinic
P2(1)/c
monoclinic
P2(1)/c
monoclinic
C2/c
monoclinic
P2(1)
space group
a/Å
20.7362(19)
10.8673(10)
12.0256(11)
100.386(2)
2665.5(4)
4
14.6799(8)
10.2113(6)
16.6281(9)
94.6660(10)
2484.3(2)
4
44.359(3)
10.5230(5)
33.2164(19)
115.458(2)
13999.5(13)
8
10.1046(9)
9.9420(8)
22.717(2)
99.837(2)
2248.6(3)
2
b/Å
c/Å
β/deg
U/Å3
Z
Dc/g cm−3
1.698
1.629
1.506
1.441
μ/mm−1
0.917
0.951
0.699
0.559
data/restraints/params
no. reflns used [>2σ(I)]
R1, wR2 [I > 2σ(I)]
R1, wR2 [all data]
GOF
6632/18/360
6632 [R(int) = 0.0504]
0.0863, 0.1860
0.1264, 0.2089
1.101
6177/0/324
6177 [R(int) = 0.0208]
0.0436, 0.1134
0.0531, 0.1209
1.042
17368/0/972
17 368 [R(int) = 0.0609]
0.0563, 0.1163
0.0858, 0.1273
1.035
10191/2/576
10 191 [R(int) = 0.0305]
0.0665, 0.1756
0.0820, 0.1875
1.077
5a/AgCF3SO3
6a/AgCF3SO3
7a/AgCF3SO3
6a/HgCl2
formula
C31H36AgF3N4O3S
709.57
C40H44AgF3N4O4S
841.72
C44H44AgF3N4O4S
889.76
C38H40HgCl2N4
824.23
M
T/K
298
100
90
90
cryst syst
monoclinic
C2/c
monoclinic
P2(1)/c
monoclinic
Cc
monoclinic
C2/c
space group
a/Å
13.298(2)
14.800(2)
17.760(3)
107.748(3)
3329.0(9)
4
10.1283(7)
19.0025(14)
19.4108(14)
94.6190(10)
3723.7(5)
4
19.473(2)
16.4227(17)
14.1119(15)
117.169(2)
4015.1(7)
4
22.1820(19)
7.6862(6)
20.9636(16)
104.577(2)
3459.1(5)
4
b/Å
c/Å
β/deg
U/Å3
Z
Dc/g cm−3
1.416
1.501
1.472
1.583
μ/mm−1
0.721
0.660
0.617
4.637
data/restraints/params
no. reflns used [>2σ(I)]
R1, wR2 [I > 2σ(I)]
R1, wR2 [all data]
GOF
4165/12/235
4165 [R(int) = 0.0468]
0.1150, 0.2698
0.1300, 0.2769
1.393
9217/7/486
9217 [R(int) = 0.0232]
0.0461, 0.1179
0.0501, 0.1207
1.102
9300/53/519
9300 [R(int) = 0.0285]
0.0737, 0.1960
0.0856, 0.2104
1.043
4305/0/209
4305 [R(int) = 0.0476]
0.0515, 0.1420
0.0521, 0.1424
1.185
7a/Cu(CF3SO3)2
5a
formula
M
C44H42CuF6N4O7S2
980.48
C30H36N4
452.63
298
T/K
90
cryst syst
space group
a/Å
monoclinic
P2(1)/c
triclinic
P1
̅
12.9581(8)
16.6195(10)
20.0520(11)
11.5947(16)
14.973(2)
16.169(2)
81.717(3)
78.957(2)
68.798(3)
2560.0(6)
4
b/Å
c/Å
α/deg
β/deg
γ/deg
U/Å3
108.536(2)
4094.3(4)
Z
4
Dc/g cm−3
μ/mm−1
1.591
1.174
0.722
0.070
data/restraints/params
10184/0/593
10 184 [R(int) = 0.0737]
0.0613, 0.1211
0.0979, 0.1354
1.026
12487/0/629
12 487 [R(int) = 0.0200]
0.0643, 0.1717
0.1317, 0.2328
1.028
no. reflns used [>2σ(I)]
R1, wR2 [I > 2σ(I)]
R1, wR2 [all data]
GOF
2546
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
2b: Yield 85%. Mp: 135−136.5 °C. 1H NMR (CDCl3): δ 7.48−7.29
(m, 10H), 7.16 (s, 2H), 3.82 (s, 2H), 3.70 (s, 2H), 3.31−3.17 (m,
8H), 2.61 (t, J = 5.7 Hz, 4H). FAB-MS (m/z) (matrix: DTT/TG =
1:2): 381 ([M + 1]+, 100%). Anal. Calcd for C22H28N4O2: C, 69.45; H,
7.42; N, 14.73. Found: C, 69.40; H, 7.40; N, 14.84.
C34H40N4O2: C, 76.09; H, 7.51; N, 10.44. Found: C, 76.14; H, 7.53;
N, 10.39.
1
4a: Yield 77%. Yellow oil. H NMR (CD2Cl2): δ 7.13−7.23 (m,
12H), 6.91−7.03 (m, 16H), 3.53 (s, 4H), 2.51−2.69 (m, 18H). 13C
NMR (CD2Cl2): δ 148.3, 147.1, 134.4, 130.3, 129.6, 124.38, 124.36,
123.0, 59.7, 52.1, 45.9. FAB-MS (m/z) (matrix: DTT/TG = 1:1): 687
([M + 1]+, 20%). Anal. Calcd for C46H50N6+H2O: C, 78.37; H, 7.43;
N, 11.92. Found: C, 78.25; H, 7.38; N, 11.63.
1
3b: Yield 80%. Mp: 162.8−163.9 °C. H NMR (CDCl3): δ 7.35−
7.31 (m, 4H), 7.28−7.24 (m, 4H), 7.13−7.07 (m, 6H), 7.02−6.96 (m,
8H), 3.78 (s, 2H), 3.65 (s, 2H), 3.25 (s, 8H), 2.62 (t, J = 5.5 Hz, 4H).
FAB-MS (m/z) (matrix: DTT/TG = 1:2): 565 ([M + 1]+, 30%). Anal.
Calcd for C34H36N4O4+0.5CH3OH: C, 71.36; H, 6.60; N, 9.65.
Found: C, 71.56; H, 6.41; N, 9.49.
1
5a: Yield 43%. Mp: 134.0−134.8 °C. H NMR (CD2Cl2): δ 8.14−
8.20 (m, 2H), 7.85−7.91 (m, 2H), 7.80 (d, J = 8.1 Hz, 2H), 7.40−7.57
(m, 8H), 4.01 (s, 4H), 2.63 (s,16H). 13C NMR (CD2Cl2): δ 135.3,
134.2, 132.8, 129.0, 128.0, 127.8, 126.4, 125.9, 125.8, 124.1, 58.2, 52.7,
45.8. FAB-MS (m/z) (matrix: DTT/TG = 1:1): 687 ([M + 1]+, 20%).
Anal. Calcd for C30H36N4: C, 79.60; H, 8.02; N, 12.38. Found: C,
79.38; H, 8.05; N, 12.42.
1
4b: Yield 73%. Mp: 202.4−203.2 °C. H NMR (CDCl3): δ 7.23−
7.17 (m, 10H), 7.14−7.11 (m, 4H), 7.01−6.96 (m, 16H), 3.73 (s, 2H),
3.61 (s, 2H), 3.27 (s, 4H), 3.23−3.22 (m, 4H), 2.63 (t, J = 5.5 Hz,
4H). FAB-MS (m/z) (matrix: DTT/TG = 1:2): 715 ([M + 1]+, 2%).
Anal. Calcd for C46H46N6O2+0.25H2O: C, 76.80; H, 6.51; N, 11.68.
Found: C, 76.83; H, 6.55; N, 11.65.
6a: Yield 69%. Mp: 223.5−224.9 °C. 1H NMR (CD2Cl2): δ 8.47 (s,
2H), 8.28 (d, J = 9.0 Hz, 4H), 8.04 (d, J = 8.5 Hz, 4H), 7.47 (t, J = 7.6
Hz, 4H), 7.21 (t, J = 7.6 Hz, 4H), 4.42 (s, 4H), 2.63 (d, J = 8.1 Hz,
16H). 13C NMR (CD2Cl2): δ 132.0, 131.8, 130.0, 130.3, 128.0, 126.6,
125.4, 124.9, 52.9, 52.4, 45.7. FAB-MS (m/z) (matrix: DTT/TG =
1:2): 553 ([M + 1]+, 100%). Anal. Calcd for C38H40N4: C, 82.57; H,
7.29; N, 10.14. Found: C, 82.24; H, 7.26; N, 10.09.
5b: Yield 43%. Mp: 132.6−133.0 °C. 1H NMR (D2O in the
presence of NaOD): δ 8.30−8.37 (m, 2H), 8.00 (d, J = 7.6 Hz, 2H),
7.82−7.89 (m, 2H), 7.58−7.69 (m, 3H), 7.42−7.54 (s, 5H), 5.08 (s,
2H), 4.27 (s, 2H), 3.20−3.51 (m, 16H). FAB-MS (m/z) (matrix:
DTT/TG = 1:2): 481 ([M + 1]+, 100%). Anal. Calcd for
C30H32N4O2+0.5CHCl3: C, 67.80; H, 6.06; N, 10.37. Found: C,
67.47; H, 6.32; N, 10.42.
1
7a: Yield 28%. Mp: 165.2−166.1 °C (dec). H NMR (CD2Cl2): δ
8.45 (d, J = 9.3 Hz, 2H), 8.21 (d, J = 7.5 Hz, 2H), 7.90−8.14 (m,
14H), 4.28 (s, 4H), 2.55−2.73 (m, 16H). 13C NMR (CD2Cl2): δ
133.6, 131.8, 131.2, 130.9, 130.0, 128.5, 127.9, 127.8, 127.4, 126.3,
125.5, 125.4, 125.24, 125.23, 125.1, 123.7, 58.3, 52.9, 46.0. FAB-MS
(m/z) (matrix: DTT/TG = 1:2): 601 ([M + 1]+, 50%). Anal. Calcd
for C42H40N4: C, 83.96; H, 6.71; N, 9.33. Found: C, 84.02; H, 6.83; N,
9.20.
6b: Yield 71%. Mp: 273.8−274.5 °C. 1H NMR (CDCl3): δ 8.53 (s,
1H,), 8.41−8.39 (m, 2H), 8.24 (d, J = 9.1 Hz, 2H), 7.52−7.45 (m,
4H), 7.32 (t, J = 6.6 Hz, 2H), 8.42 (s, 1H), 8.09−8.06 (m, 2H), 7.97
(d, J = 8.4 Hz, 2H), 7.10 (t, J = 6.6 Hz, 2H), 6.69 (s, 2H), 4.80 (s,
2H), 4.64 (s, 2H), 3.27(s, 4H), 2.99−2.95 (m, 4H), 2.62 (t, J = 5.8 Hz,
4H). FAB-MS (m/z) (matrix: DTT/TG = 1:2): 581 ([M + 1]+, 20%).
Anal. Calcd for C38H36N4O2+0.5CH3OH: C, 77.99; H, 6.29; N, 9.57.
Found: C, 78.08; H, 6.34; N, 9.50.
Preparation of Metal Ion Complexes. The ligand (0.0151
mmol) in chloroform (1 mL) was added to the corresponding metal
salt (AgOTf, Cu(OTf)2, or HgCl2) (0.0153 mmol) in methanol (1
mL). Crystals were obtained quantitatively on evaporation of the
solvent.
1a/AgOTf. Anal. Calcd for C23H28N4F7O3SAg: C, 40.54; H, 4.14;
N, 8.22. Found: C, 40.64; H, 3.66; N, 7.95.
2a/AgOTf. Anal. Calcd for C23H32N4F3O3SAg: C, 45.33; H, 5.29;
N, 9.19. Found: C, 45.15; H, 5.41; N,8.95.
3a/AgOTf. Anal. Calcd for C35H40N4F3O3SAg: C, 52.97; H, 5.08;
N, 7.06. Found: C, 53.06; H, 5.02; N, 7.01.
4a/AgOTf. Anal. Calcd for C47H50N6F3O3SAg: C, 59.81; H, 5.34;
N, 8.90. Found: C, 59.67; H, 5.18; N, 8.85.
5a/AgOTf. Anal. Calcd for C31H36N4F3O3SAg+0.8CHCl3: C,
47.44; H, 4.61; N, 6.96. Found: C, 47.39; H, 4.29; N, 6.96.
6a/AgOTf. Anal. Calcd for C39H40N4F3O3SAg+0.6CHCl3: C,
53.97; H, 4.64; N, 6.36. Found: C, 54.07; H, 4.62; N, 6.42.
7a/AgOTf. Anal. Calcd for C43H40N4F3O3SAg+0.1CHCl3: C,
59.53; H, 4.65; N, 6.44. Found: C, 59.28; H, 4.42; N, 6.46.
7a/CuOTf2. Anal. Calcd for C44H40N4F6O6S2Cu: C, 54.91; H, 4.19;
N, 5.82. Found: C, 54.94; H, 3.93; N, 5.73.
7b: Yield 84%. Mp: 251.3−252.1 °C. 1H NMR (CD2Cl2): δ 8.41 (d,
J = 9.5 Hz, 1H), 8.33 (d, J = 9.5 Hz, 1H), 8.23 (d, J = 6.9 Hz, 1H),
8.17 (d, J = 8.1 Hz, 1H), 8.15−8.07 (m, 4H), 8.03−7.96 (m, 3H), 7.90
(t, J = 7.7 Hz, 1H), 7.87−7.85 (m, 2H), 7.82−7.76 (m, 3H), 7.54 (d, J
= 9.1 Hz, 1H), 6.88 (s, 2H) 4.46 (s, 2H), 4.34 (s, 2H), 3.32 (s, 4H),
3.02−3.01 (m, 4H), 2.63 (t, J = 5.8 Hz, 4H). FAB-MS (m/z) (matrix:
DTT/TG = 1:2): 629 ([M + 1]+, 20%). Anal. Calcd for C42H36N4O2:
C, 80.23; H, 5.77; N, 8.91. Found: C, 80.00; H, 5.88; N, 8.79.
General Procedure for Reduction of 4,10-Disubsituted-
1,4,7,10-tetraazacyclododecane-2,12-diones. A mixture of 1b
(2.00 mmol) and DIBAL-H (40 mL, 1 mol/L solution in THF) was
stirred for 1 day at room temperature. After benzene (120 mL), NaF
(160 mmol), and water (2 mL) were added at 0 °C, the mixture was
stirred a further day at room temperature under an argon atmosphere.
The mixture was filtered, and the filtrate was evaporated under
reduced pressure. The residual solid was recrystallized from
1
acetonitrile to give 1a in 70% yield. Mp: 157.1−158.2 °C. H NMR
(CD2Cl2): δ 6.91 (d, J = 6.0 Hz, 4H), 6.73 (tt, J1 = 9.1 Hz, J2 = 2.4 Hz,
2H), 3.59 (s, 4H), 2.63 (broad s, 8H), 2.56 (broad d, J = 4.9 Hz, 8H).
6a/HgCl2. Anal. Calcd for C38H40N4Cl2Hg+1.3CHCl3: C, 48.19; H,
4.25; N, 5.72. Found: C, 48.27; H, 4.22; N, 5.92.
1
3
13C NMR* (CD2Cl2): δ 163.4 (dd, JCF = 248.0 and JCF = 12.7 Hz),
144.4 (t, 3JCF = 8.5 Hz), 112.0 (dd, 2JCF = 24.4 Hz and 4JCF = 6.2 Hz),
Crystals of the metal complexes with 1a−7a were mounted on top
of a glass fiber, and data collections were performed using a Bruker
SMART CCD area diffractometer at 90−223 K. Data were corrected
for Lorentz and polarization effects, and absorption corrections were
applied using the SADABS10 program. Structures were solved by a
direct method and subsequent difference-Fourier syntheses using the
program SHELEX.11 All non-hydrogen atoms were refined anisotropi-
cally, and hydrogen atoms were placed at calculated positions and then
refined using Uiso(H) = 1.2Ueq(C). The crystallographic refinement
parameters of the complexes are summarized in Table 1.
2
102.7 (t, JCF = 25.5 Hz), 59.6, 52.2, 45.6. FAB-MS (m/z) (matrix:
DTT/TG = 1:2): 425 ([M + 1]+, 100%). Anal. Calcd for C22H28N4F4:
C, 62.25; H, 6.65; N, 13.20. Found: C, 62.32; H, 6.75; N, 13.22.
*Signs of 13C−19F coupling constants in the 13C NMR spectrum of 1a
have not been considered.
1
2a: Yield 56%. Mp: 200.0−201.0 °C. H NMR (CD2Cl2): δ 7.25−
7.42 (m, 10H), 3.56 (s, 4H), 2.56−2.64 (m, 18H). 13C NMR
(CD2Cl2): δ 140.26, 129.6, 128.6, 127.4, 60.3, 52.1, 45.6. FAB-MS (m/
z) (matrix: DTT/TG = 1:2): 353 ([M + 1]+, 100%). Anal. Calcd for
C22H32N4: C, 74.96; H, 9.15; N, 15.89. Found: C, 75.09; H, 9.19; N,
13.90.
ASSOCIATED CONTENT
■
1
3a: Yield 45%. Mp: 98.5−100.2 °C. H NMR (CD2Cl2): δ 7.24−
S
* Supporting Information
7.35 (m, 8H), 7.07 (t, J = 7.3 Hz, 2H), 6.91−7.02 (m, 8H), 3.53 (s,
4H), 2.49−2.65 (m, 18H). 13C NMR (CD2Cl2): δ 157.7, 156.7, 135.0,
130.8, 130.1, 123.6, 119.2, 118.9, 59.4, 52.1, 45.6. FAB-MS (m/z)
(matrix: DTT/TG = 1:2): 537 ([M + 1]+, 20%). Anal. Calcd for
Spectral data and titration experiments (PDF). Crystallographic
data of metal complexes with 1a−7a (CIF). These materials are
available free of charge via the Internet at http://pubs.acs.org
2547
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
Q.-J.; Zhang, N.; Jin, Y.-C.; Zhao, H.-X.; Lin, L.-R.; Huang, R.-B.;
Zheng, L.-S. Inorg. Chem. Commun. 2009, 12, 782. Sun, D.; Zhang, N.;
Luo, G. G.; Huang, R. B.; Zheng, L. S. Acta Crystallogr. C 2010, C66,
m75. Sun, D.; Zhang, N.; Xu, Q.-J.; Huang, R.-B.; Zheng, L.-S. J.
Organomet. Chem. 2010, 695, 1598. Tan, H.-Y.; Zhang, H.-X.; Ou, H.-
D.; Kang, B.-S. Inorg. Chim. Acta 2004, 357, 869. Trzebuniak, K.;
Zarychta, B.; Olijnyk, V. J. Mol. Struct. 2011, 1006, 266. Wadepohl, H.;
Pritzkow, H. Acta Crystallogr. 2001, C57, 383. Wang, F. Y.; Jiang, X. B.;
Tan, X. J.; Xing, D. X. Acta Crystallogr. 2011, C67, 218. Wen, M.;
Munakata, M.; Suenaga, Y.; Kuroda-Sowa, T.; Maekawa, M. Inorg.
Chim. Acta 2002, 332, 18. Wen, Q.-S.; Zhou, C.-L.; Qin, D.-B. Acta
Crystallogr. 2010, E66, m1030. Yesilel, O. Z.; Guenay, G.;
Buyukgungor, O. Polyhedron 2011, 30, 364. Zang, S.-Q.; Han, J.;
Mak, T. C. W. Organometallics 2009, 28, 2677. Zhao, L.; Mak, T. C. W.
Organometallics 2007, 26, 4439. Zhao, L.; Zhao, X.-L.; Mak, T. C. W.
Chem.−Eur. J. 2007, 13, 5927. Zheng, S. L.; Tong, M. L.; Tan, S. D.;
Wang, Y.; Shi, J. X.; Tong, Y. X.; Lee, H. K.; Chen, X. M.
Organometallics 2001, 20, 5319. Zheng, S.-L.; Zhang, J.-P.; Wong, W.-
T.; Chen, X.-M. J. Am. Chem. Soc. 2003, 125, 6882. Zheng, X.-F.; Zhu,
L.-G. Cryst. Growth Des. 2009, 9, 4407. Zheng, X.-F.; Zhu, L.-G. Inorg.
Chim. Acta 2011, 365, 419. Zhong, J. C.; Munakata, M.; Kuroda-Sowa,
T.; Maekawa, M.; Suenaga, Y.; Konaka, H. Inorg. Chem. 2001, 40,
3191. Zhou, Y.; Zhang, X.; Chen, W.; Qiu, H. J. Organomet. Chem.
2008, 693, 205.
AUTHOR INFORMATION
Corresponding Author
*E-mail: habata@chem.sci.toho-u.ac.jp.
Notes
■
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This research was supported by Grants-in-Aid (08026969 and
11011761), a High-Tech Research Center project (2005-2009),
and the Supported Program for Strategic Research Foundation
at Private Universities (2012−2016) from the Ministry of
Education, Culture, Sports, Science and Technology of Japan,
and the Futaba Memorial Foundation, for Y.H.
DEDICATION
■
This paper is dedicated to the late Professor Sadatoshi Akabori,
who passed away on October 3, 2012.
REFERENCES
■
(1) (a) Gokel, G. W. Chem. Commun. 2003, 2847. (b) Gokel, G. W.;
Barbour, L. J.; De, W. S. L.; Meadows, E. S. Coord. Chem. Rev. 2001,
222, 127. (c) Gokel, G. W.; De, W. S. L.; Meadows, E. S. Eur. J. Org.
Chem. 2000, 2967. (d) Petrella, A. J.; Raston, C. L. J. Organomet. Chem.
2004, 689, 4125. (e) Xu, Z. Coord. Chem. Rev. 2006, 250, 2745.
(f) Zaric, S. D. Eur. J. Inorg. Chem. 2003, 2197. (g) Munakata, M.; Wu,
L. P.; Ning, G. L. Coord. Chem. Rev. 2000, 198, 171.
(2) (a) Abe, M.; Eto, M.; Yamaguchi, K.; Yamasaki, M.; Misaka, J.;
Yoshitake, Y.; Otsuka, M.; Harano, K. Tetrahedron 2012, 68, 3566.
(b) Krenske, E. H.; Houk, K. N. Acc. Chem. Res. Ahead of Print.
(c) Nishio, M. Tetrahedron 2005, 61, 6923. (d) Nishio, M.
CrystEngComm 2004, 6, 130. (e) Nishio, M.; Umezawa, Y.; Hirota,
M.; Takeuchi, Y. Tetrahedron 1995, 51, 8665.
(4) (a) Habata, Y.; Ikeda, M.; Yamada, S.; Takahashi, H.; Ueno, S.;
Suzuki, T.; Kuwahara, S. Org. Lett. 2014, 14, 4576. (b) Habata, Y.;
Okeda, Y.; Ikeda, M.; Kuwahara, S. Submitted.
(5) Neuburger, M.; Zehnder, M.; Kaden, T. A. Supramol. Chem.
1993, 2, 103. DeSimone, R. E.; Blinn, E. L.; Mucker, K. F. Inorg. Nucl.
Chem. Lett. 1980, 16, 23. Kobayashi, K.; Sakurai, T.; Hasegawa, A.;
Tsuboyama, S.; Tsuboyama, K. Acta Crystallogr. 1982, B38, 1154.
Kong, D.-Y.; Xie, Y.-L.; Xie, Y.-Y.; Huang, X.-Y. Jiegou Huaxue 2000,
19, 39. Kong, D.; Huang, X.; Xie, Y. Inorg. Chim. Acta 2002, 340, 133.
Kong, D.; Meng, L.; Song, L.; Xie, Y. Transition Met. Chem. 1999, 24,
553. Sakurai, T.; Tsuboyama, K.; Tsuboyama, S.; Kobayashi, K. Nippon
Kessho Gakkaishi 1983, 25, 299. Sakurai, T.; Kobayashi, K.; Hasegawa,
A.; Tsuboyama, S.; Tsuboyama, K. Acta Crystallogr. 1982, B38, 107.
Sakurai, T.; Kobayashi, K.; Kanari, T.; Kawata, T.; Higashi, I.;
Tsuboyama, S.; Tsuboyama, K. Acta Crystallogr. 1983, B39, 84.
Sakurai, T.; Kobayashi, K.; Masuda, H.; Tsuboyama, S.; Tsuboyama, K.
Acta Crystallogr. 1983, C39, 334. Tsuboyama, S.; Kobayashi, K.;
Sakurai, T.; Tsuboyama, K. Acta Crystallogr. 1984, C40, 1178.
Tsuboyama, S.; Saitoh, N.; Kobayashi, K.; Tsuboyama, K.; Sakurai,
T. Anal. Sci. 1989, 5, 115.
(6) “Argentivorous” is different from “argentophilic”. “Argentophilic”
is used in the sense of Ag+−Ag+ interactions. For example:
(a) Constable, E. C.; Housecroft, C. E.; Kopecky, P.; Neuburger,
M.; Zampese, J. A. Inorg. Chem. Commun. 2013, 27, 159−162. (b) Luo,
G.-G.; Wu, D.-L.; Liu, L.; Wu, S.-H.; Li, D.-X.; Xiao, Z.-J.; Dai, J.-C. J.
Mol. Struct. 2012, 1014, 92−96. (c) Santra, R.; Garai, M.; Mondal, D.;
Biradha, K. Chemistry 2013, 19, 489−93. (d) Senchyk, G. A.;
Bukhan’ko, V. O.; Lysenko, A. B.; Krautscheid, H.; Rusanov, E. B.;
Chernega, A. N.; Karbowiak, M.; Domasevitch, K. V. Inorg. Chem.
2012, 51, 8025−8033. (e) Stephenson, A.; Ward, M. D. Chem.
Commun. (Cambridge, U. K.) 2012, 48, 3605−3607. (f) Xu, J.; Gao, S.;
Ng, S. W.; Tiekink, E. R. T. Acta Crystallogr., Sect. E Struct. Rep. Online
2012, 68, m639−40. (g) Xu, J.; Gao, S.; Ng, S. W.; Tiekink, E. R. T.
Acta Crystallogr., Sect. E: Struct. Rep. Online 2012, E68, m639−m640.
(h) Yang, G.; Baran, P.; Martinez, A. R.; Raptis, R. G. Cryst. Growth
Des. 2013, 13, 264−269.
(3) Baudron, S. A. CrystEngComm 2010, 12, 2288. Beziau, A.;
Baudron, S. A.; Hosseini, M. W. Dalton Trans. 2012, 41, 7227.
Chainok, K.; Neville, S. M.; Forsyth, C. M.; Gee, W. J.; Murray, K. S.;
Batten, S. R. CrystEngComm 2012, 14, 3717. Gao, C.-Y.; Zhao, L.;
Wang, M.-X. J. Am. Chem. Soc. 2012, 134, 824. Goodgame, D. M. L.;
Grachvogel, D. A.; Williams, D. J. J. Chem. Soc., Dalton Trans. 2002,
2259. Guney, E.; Yilmaz, V. T.; Buyukgungor, O. Inorg. Chem.
Commun. 2010, 13, 563. Hamamci, S.; Yilmaz, V. T.; Buyukgungor, O.
Acta Crystallogr. C 2006, 62, m1. Hao, H.-J.; Sun, D.; Li, Y.-H.; Liu, F.-
J.; Huang, R.-B.; Zheng, L.-S. Cryst. Growth Des. 2011, 11, 3564. Ino,
I.; Wu, P.; Munakata, M.; Kuroda-Sowa, T.; Maekawa, M.; Suenaga, Y.;
Sakai, R. Inorg. Chem. 2000, 39, 5430. Kennedy, A. R.; Brown, K. G.;
Graham, D.; Kirkhouse, J. B.; Kittner, M.; Major, C.; McHugh, C. J.;
Murdoch, P.; Smith, W. E. New J. Chem. 2005, 29, 826. Khanna, S.;
Verma, S. Cryst. Growth Des. 2012, 12, 3025. Kim, S. K.; Lee, J. K.; Lee,
S. H.; Lim, M. S.; Lee, S. W.; Sim, W.; Kim, J. S. J. Org. Chem. 2004,
69, 2877. Lahtinen, T.; Wegelius, E.; Rissanen, K. New J. Chem. 2001,
25, 905−911. Li, B.; Zang, S.-Q.; Li, H.-Y.; Wu, Y.-J.; Mak, T. C. W. J.
Organomet. Chem. 2012, 708−709, 112. Li, X. Y.; Liu, Q. K.; Ma, J. P.;
Huang, R. Q.; Dong, Y. B. Acta Crystallogr. C 2009, 65, m45. Liddle, B.
J.; Hall, D.; Lindeman, S. V.; Smith, M. D.; Gardinier, J. R. Inorg.
Chem. 2009, 48, 8404. Lindeman, S. V.; Rathore, R.; Kochi, J. K. Inorg.
Chem. 2000, 39, 5707. Liu, H.-K.; Huang, X.; Lu, T.; Wang, X.; Sun,
W.-Y.; Kang, B.-S. Dalton Trans. 2008, 3178. Luo, G.-G.; Xiong, H.-B.;
Sun, D.; Wu, D.-L.; Huang, R.-B.; Dai, J.-C. Cryst. Growth Des. 2011,
11, 1948. Munakata, M.; Ning, G. L.; Suenaga, Y.; Kuroda-Sowa, T.;
Maekawa, M.; Ohta, T. Angew. Chem., Int. Ed. 2000, 39, 4555.
Munakata, M.; Wen, M.; Suenaga, Y.; Kuroda-Sowa, T.; Maekawa, M.;
Anahata, M. Polyhedron 2001, 20, 2321. Reger, D. L.; Gardinier, J. R.;
Smith, M. D. Inorg. Chem. 2004, 43, 3825. Richards, P. I.; Steiner, A.
Inorg. Chem. 2004, 43, 2810. Santra, R.; Banerjee, K.; Biradha, K.
Chem. Commun. 2011, 47, 10740. Son, J.-H.; Pudenz, M. A.;
Hoefelmeyer, J. D. Dalton Trans 2010, 39, 11081. Sumby, C. J.;
Steel, P. J. Inorg. Chim. Acta 2007, 360, 2100. Sun, D.; Luo, G.-G.; Xu,
(7) 1,4,7,10-Tetraazacyclododecane-2,6-dione was prepared accord-
ing to the procedure described in the following literature: Kodama,
M.; Kimura, E. J. Chem. Soc., Dalton Trans. 1981, 3, 694. Compounds
2a, 5a, and 6a have been prepared in different procedures. 2a: Chaux,
F.; Denat, F.; Espinosa, E.; Guilard, R. Chem. Commun. 2006, 5054.
Compound 5a: Kikuta, E.; Murata, M.; Katsube, N.; Koike, T.;
Kimura, E. J. Am. Chem. Soc. 1999, 121, 5426. Compound 6a:
Shiraishi, Y.; Kohno, Y.; Hirai, T. Ind. Eng. Chem. Res. 2005, 44, 847.
(8) Spartan ’10; Wavefunction, Inc.: Irvine, CA.
2548
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549

Inorganic Chemistry
Article
(9) Hehre, W. J.; Yu. J.; Klunzinger, P. E.; Lou, L. A Brief Guide to
Molecular Mechanics and Quantum Chemistry Calculations; Wave-
function: Irvine, CA, 1998; p 159.
(10) Sheldrick, G. M. SADABS, Program for Adsorption Correction of
Area Detector Frames; Bruker AXS, Inc.: Madison, WI, 1996.
(11) SHELXTLTM, version 5.1; Bruker AXS, Inc.: Madison, WI,
1997.
2549
dx.doi.org/10.1021/ic302511e | Inorg. Chem. 2013, 52, 2542−2549