Dinuclear silver(I) complexes of dibenzo-crown ethers and the mononuclear complex of aminobenzo-crown ether

Article abstract of DOI:10.1016/S0020-1693(02)00979-9

Three silver(I) coordination complexes of crown ethers, [Ag([15]C6)(ClO₄)₂](THF) (1), [Ag(DB[21]C7)(H₂O)]₂(ClO₄)₂ (2) and [Ag(DB[24]C8)(CF₃SO₃)]₂(acetone)

Full text of DOI:10.1016/S0020-1693(02)00979-9

Inorganica Chimica Acta 338 (2002) 111ꢀ118
/
www.elsevier.com/locate/ica
Dinuclear silver(I) complexes of dibenzo-crown ethers and the
mononuclear complex of aminobenzo-crown ether
Ming Wen a, Masahiko Maekawa b, Megumu Munakata a,*, Yusaku Suenaga a,
Takayoshi Kuroda-Sowa a
a Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
b Research Institute for Science and Technology, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
Received 28 December 2001; accepted 8 March 2002
Abstract
Three silver(I) coordination complexes of crown ethers, [Ag([15]C6)(ClO4)2](THF) (1), [Ag(DB[21]C7)(H2O)]2(ClO4)2 (2) and
[Ag(DB[24]C8)(CF3SO3)]2(acetone)2 (3) have been synthesized in different solvents and characterized structurally. The mononuclear
complex 1 and two different dinuclear complexes 2 and 3 are shown in this work. Silver(I) ions are situated in a distorted pentagonal
pyramidal geometry and form close dinuclear complex with DB[21]C7 based on cationꢀ
coordination unit involves s bonding at a part oxygen atoms of ligand oxygen base cavity and pꢀ
phenyl groups. But in 3, each DB[24]C8 host contained two silver(I) ions as guest without cationꢀ
# 2002 Elsevier Science B.V. All rights reserved.
/
p interaction in h2-fashion. This
p interaction between two parallel
p and pꢀp interaction.
/
/
/
Keywords: Silver complexes; Dinuclear complex; Cationꢀ
/
p interaction; pꢀp interaction
/
1. Introduction
tial for such an interaction has always been evident from
an electrostatic analysis of benzene.
It has become a great major goal in coordination
chemistry that of constructing coordination hostꢀguest
complexes of organic molecules with metal ions via
weak non-covalent interactions such as p-stacking,
hydrogen bonding, charge transfer interaction and
electrostatic interactions [1]. Of these interactions,
Crown ethers with their unique chemical architecture
play a prominent role and open the way to practical
designing of complexation for metal ions [6]. Some
macrocyclic crown ethers complexes have been reported
so far [7,8], but there are few coordination complexes
constructed by h2 coordination mode of benzene of
dibenzo-crown ether compounds to silver(I) ions which
contain metal ions as guest molecules. Such organome-
tallic compounds are noted as a new type of macrocyclic
crown ether coordination complexes. This study of the
synthesis and structures of silver(I) complexes of 4?-(2,6-
dinitro-4-trifluoromethyphenyl)-aminobenzo-15-crown-
5 ([15]C5), dibenzo-21-crown-7-ether (DB[21]C7) and
dibenzo-24-crown-8-ether (DB[24]C8) is a continuation
of our previous work [9], in which the formation of
silver(I) coordination complexes of dibenzo-18-crown-6-
ether has adopted h2 fashion to form dinuclear com-
plexes.
/
cationꢀ
/
p, pꢀ
/
p and charge transfer have recently re-
ceived increasing attention [2]. Cationꢀ
/
p and charge
transfer interactions can not only build novel molecular
architectures but also dramatically influence the physi-
cal properties of the fused polyaromatic solid surfaces
[3] and may cause to potential applications in electrical
conductors and photosensitive devices [4,5]. The poten-
* Corresponding author. Tel.: ꢁ
2721
E-mail address: munakata@chem.kindai.ac.jp (M. Munakata).
/
81-6-721 2332; fax: ꢁ81-6-6723
/
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 0 - 1 6 9 3 ( 0 2 ) 0 0 9 7 9 - 9

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M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ118
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different kinds of symmetry to the hosts. Here, we
describe the syntheses and characterization of this
system to show how the mobile silver(I) ions are
assembled as guests located in the oxygen base cavity
of ligand to build up distinctive molecular architectures.
2. Experimental
2.1. General procedures
All reactions and manipulations were performed
under an argon atmosphere by using Schlenk tech-
niques. All chemicals were reagent grade and used as
supplied without further purification. Solvents were
dried and distilled by using standards methods before
use. Reagent grade [15]C6, DB[21]C7 and DB[24]C8
were purchased from Tokyo Chemical Industry Co.,
Ltd., whereas silver perchlorate and all other chemicals
were purchased from Wako Pure Chemical, Inc. and
used as received. The IR spectra were measured as KBr
disks on a JASCO FT/IR-8000 spectrometer at room
temperature (r.t.). All crystallizations of the silver
complexes were performed in the dark.
Safety Note: Perchlorate salts with organic ligands are
potentially explosive! Only small amounts of materials
should be prepared, and these should be handled with
the necessary precautions.
2.2. Syntheses
2.2.1. [Ag([15]C5)(ClO4)](THF) (1)
To a THF solution (10 ml) containing silver perchlo-
rate (22.54 mg, 0.1 mmol), [15]C5 (10.34 mg, 0.02 mmol)
was added. The mixture was stirred at r.t. for 20 min
and filtered. A portion of the filtrate (2 ml) was
introduced into a 7 mm glass tube and layered with n-
pentane as a diffusion solvent. The glass tube was then
sealed under Argon and left standing at r.t. for 5 days,
orange yellow block crystals of 1 suitable for X-ray
determination were isolated. Anal. Calc. For AgCl-
F3O14N3C25H30: C, 37.65; H, 3.76. Found: C, 37.81; H,
3.75%. Main IR bands (KBr, n (cmꢂ1)): 2875(m),
1638(s), 1543(s), 1513(s), 1314(s), 1287(s), 1131(s),
937(m), 625(m). 1H NMR (300 MHz, CD3COCD3)
dH 9.90 (s, H), 8.58 (s, 2H), 7.08 (s, H), 7.06 (d, H), 6.88
(d, H), 4.24 (t, 4H), 4.01 (t, 4H), 3.87 (s, 8H).
Our continuing interest in the construction of supra-
molecular architecture of metal ions with crown ether
include phenyl group lets us consider the incorporation
of metal ions into the crown ether systems for the
generation of novel molecular or supramolecular net-
works with potential physicochemical properties. In
order to design new types of silver(I) complexes with
macrocyclic crown ether ligands, we have chosen the
readily available [15]C6, DB[21]C7 and DB[24]C8, wish
to synthesize silver(I) complexes to obtain the possibility
of unplanarity complexation in the cationꢀp complexes
/
and to examine any unusual coordination and reactivity
which the macrocyclic crown ethers ligand might induce.
This has prompted us to consider the possibility that the
crystal engineering of such a system with designed
structures may be realized by using simple controlling
factors such as ligand and solvents [10].
2.2.2. [Ag(DB[21]C7)(H2O)]2(ClO4)2 (2)
A solution of DB[21]C7 (36.0 mg, 0.1 mmol) in
In this work, we have synthesized three silver(I)
coordination complexes, [Ag([15]C5)(ClO4)](THF),
[Ag(DB[21]C7)(H2O)]2(ClO4)2 and [Ag2(DB[24]C8)-
(ClO4)2]. The hosts phenyl crown ether using different
mode bind with guests silver(I) ions and built into a
variety of sterically confining groups which impart
acetone (10 ml) was treated with Ag(ClO4)×
/
H2O (45.0
mg, 0.2 mmol). After stirring for 20 min the reaction
mixture was filtered. The filtrate was transferred to a 7
mm diameter glass tube under argon and was layered by
n-pentane as a diffusion solvent. The glass tube was
sealed under argon and standing at r.t. for 6 days

M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ
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118
113
Table 1
Crystallographic data for complexes 1, 2 and 3
Complex
Formula
1
2
3
AgClF3O14N3C25H30
796.84
triclinic
Ag2Cl2O24C44H60
1259.59
triclinic
Ag2Cl2O16C24H32
863.15
Formula weight
Crystal system
Space group
monoclinic
P21/c (#14)
8.734(1)
¯
1 (#2)
¯
P1 (#2)
P
/
/
˚
a (A)
13.262(3)
14.210(3)
8.498(1)
99.255(2)
92.340(2)
107.876(7)
1497.4(5)
2
10.512(1)
13.610(2)
9.3476(7)
91.287(3)
109.996(1)
108.392(5)
1179.7(2)
1
˚
b (A)
9.8652(7)
17.1773(6)
˚
c (A)
a (8)
b (8)
95.4652(7)
g (8)
3
V (A )
˚
1473.2(2)
2
864.00
Z
F(000)
T (8C)
808.00
ꢂ123.0
1.767
644.00
ꢂ123.0
1.773
ꢂ123.0
1.946
r (g cmꢂ3
)
˚
l (A) (Mo Ka)
0.71069
8.54
0.71069
10.31
0.71069
15.83
m (cmꢂ1
Number of reflections measured
)
23 026 (total)
6744 (unique)
6415
18 970 (total)
5393(unique)
5051
15 632 (total)
3331 (unique)
3192
Number of observed reflections [I ꢀ2s(I)]
Number of variable parameters
Residuals: R; Rw
490
0.029, 0.075
1.05
415
0.022, 0.050
1.10
265
0.022;0.050
1.04
Goodness-of-fit
RꢃS½½F0½-½F0½½/S½Fo½. Rv ꢃ[S v (Fo2ꢂFc2)2/S v (Fo2)2]1/2
.
colorless platelet single crystals of 2 were obtained.
Anal. Calc. For Ag2Cl2O24C44H60: C, 41.92; H, 4.76.
Found: C, 41.93; H, 4.74%. Main IR bands (KBr, n
(cmꢂ1)): 2931(m), 1593(m), 1505(s), 1454(m), 1254(s),
1212(m), 1107(s), 946(m), 626(m). H NMR (300 MHz,
CD3COCD3) dH 7.05(t, 4H), 6.97 (d, 4H), 4.27 (t, 8H),
4.04 (t, 4H), 3.94 (t, 4H), 3.85(s, 4H).
were accumulated using 4.0 ms (458 pulse) and 16 K data
points were collected over a bandwidth of 15 KHz. The
probe temperature was set at 23 8C and a 5 mm
diameter sample tube was used. All deuterated solvents
were dried by molecular sieves before use. Tetramethyl-
silane was used as an internal reference.
1
2.4. Crystallography
2.2.3. [Ag2(DB[24]C8)(ClO4)2] (3)
Similar to the synthesis of 2, DB[24]C8 (44.8 mg, 0.1
The single crystal X-ray measurements for all com-
plexes were made on a Quantum CCD area detector
coupled with a Rigaku AFC8 diffractometer with
mmol) was added to a solution of Ag(ClO4)×
/
H2O (45.0
mg, 0.2 mmol) in acetone (10 ml). The mixture was
stirred at r.t. for 20 min, and the resultant colorless
solution was filtered. The filtrate was introduced into a 7
mm diameter glass tube under argon and was layered by
n-pentane as a diffusion solvent. The glass tube was
sealed under argon and wrapped with aluminum foil.
The filtrate was left standing at r.t. for 6 days, the
colorless block single crystals of 2 were obtained. Anal.
Calc. For Ag2Cl2O16C24H32: C, 33.37; H, 3.71. Found:
C, 32.34; H, 3.73%. Main IR bands (KBr, n (cmꢂ1):
3425(w), 2924(m), 1592(m), 1503(s), 1455(m), 1255(s),
1216(m), 1089(s), 938(m), 753(m), 625(s). 1H NMR (300
MHz, CD3COCD3) dH 7.15 (t, 4H), 7.04 (d, 4H), 4.34
(t, 8H), 3.93 (t, 8H), 3.81 (s, 8H).
graphite monochromated Mo Ka radiation (lꢃ
/
˚
0.71069 A) at a temperature of ꢂ
/
12391 8C. A suitable
/
single crystal was mounted on a glass fiber. Intensity
data were collected by using standard scan techniques
(v ꢀ2u) to a maximum 2u value of 55.08 for 1, 55.48 for
/
2 and 3, respectively. All intensity data were corrected
for Lorentz and polarization effects. The structures were
solved by direct methods (SIR88 [11] for 1, SAPI91 [12] for
2, SIR97 [13] for 3) expanded using Fourier techniques
[14]. All non-H atoms were refined with anisotropic
thermal parameters. The final cycle of full-matrix least-
squares refinements [15] for all the structures was
performed on these data having I ꢀ
anisotropic thermal parameters for non-hydrogen
atoms. Reliability factors are defined as RꢃS½½F0½ꢂ
Fc ) /S v(Fo2)2]1/2. All
/
2s(I) and included
2.3. 1H NMR measurement
/
/
2
2 2
½Fc½½/S½Fo½ and Rv ꢃ
/
[S v(Fo ꢂ
/
1H NMR spectra were measured on a JEOL GSX 270
crystallographic computations were performed using
FT NMR spectrometer. The transients of 3000ꢀ5000
/
the TEXSAN package [16]. Details of the X-ray experi-

114
M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ118
/
Table 2
˚
Selected bond lengths (A) and bond angles (8) for complexes 1, 2 and 3
Complex 1
Bond lengths
Ag(1)ꢀO(5)
Ag(1)ꢀO(8)
2.444(2)
2.568(2)
Ag(1)ꢀO(6)
Ag(1)ꢀO(9)
2.479(1)
2.414(2)
Ag(1)ꢀO(7)
Ag(1)ꢀO(10)
2.402(2)
2.515(2)
Bond angles
O(5)ꢀAg(1)ꢀO(10)
O(5)ꢀAg(1)ꢀO(8)
O(6)ꢀAg(1)ꢀO(9)
O(7)ꢀAg(1)ꢀO(8)
O(9)ꢀAg(1)ꢀO(10)
94.48(8)
124.09(5)
118.92(6)
68.95(5)
O(5)ꢀAg(1)ꢀO(6)
O(5)ꢀAg(1)ꢀO(9)
O(6)ꢀAg(1)ꢀO(7)
O(7)ꢀAg(1)ꢀO(9)
O(8)ꢀAg(1)ꢀO(9)
67.30(5)
64.93(5)
69.79(6)
132.69(5)
66.55(6)
O(5)ꢀAg(1)ꢀO(7)
O(6)ꢀAg(1)ꢀO(10)
O(6)ꢀAg(1)ꢀO(8)
O(7)ꢀAg(1)ꢀO(10)
O(8)ꢀAg(1)ꢀO(10)
135.85(5)
93.90(5)
117.45(5)
98.28(8)
136.61(7)
125.11(7)
Complex 2
Bond lengths
Ag(1)ꢀO(5)
Ag(1)ꢀO(8)
C(11)ꢀC(12)
2.633(2)
2.310(1)
1.418(2)
Ag(1)ꢀO(6)
Ag(1)ꢀC(20)
C(20)ꢀC(21)
2.547(1)
2.598(2)
1.387(3)
Ag(1)ꢀO(7)
2.406(1)
2.572(2)
59.55(4)
Ag(1)ꢀC(21)
O(5)ꢀAg(1)ꢀO(6)
Bond angles
O(5)ꢀAg(1)ꢀO(7)
O(5)ꢀAg(1)ꢀC(21)
O(6)ꢀAg(1)ꢀC(20)
O(7)ꢀAg(1)ꢀC(20)
O(8)ꢀAg(1)ꢀC(21)
123.89(4)
103.61(5)
105.94(5)
121.42(5)
123.29(5)
O(5)ꢀAg(1)ꢀO(8)
O(6)ꢀAg(1)ꢀO(7)
O(6)ꢀAg(1)ꢀC(21)
O(7)ꢀAg(1)ꢀC(21)
C(20)ꢀAg(1)ꢀC(21)
87.13(5)
65.96(4)
92.20(4)
90.39(5)
31.11(6)
O(5)ꢀAg(1)ꢀC(20)
O(6)ꢀAg(1)ꢀO(8)
O(7)ꢀAg(1)ꢀO(8)
O(8)ꢀAg(1)ꢀC(20)
86.61(5)
137.26(5)
129.04(6)
97.14(5)
Complex 3
Bond lengths
Ag(1)ꢀO(1)
Ag(1)ꢀO(3)
2.686(1)
2.585(1)
Ag(1)ꢀO(1)
Ag(1)ꢀO(4)
2.509(1)
2.542(1)
Ag(1)ꢀO(2)
Ag(1)ꢀO(5)
2.405(1)
2.494(2)
Bond angles
O(1)ꢀAg(1)ꢀO(3)
O(1*)ꢀAg(1)ꢀO(4)
O(1*)ꢀAg(1)ꢀO(5)
O(2)ꢀAg(1)ꢀO(3)
O(4)ꢀAg(1)ꢀO(5)
Ag(1)ꢀO(1)ꢀAg(1*)
135.06(4)
67.05(4)
87.31(5)
66.71(4)
93.10(5)
89.36(4)
O(1)ꢀAg(1)ꢀO(1*)
O(1)ꢀAg(1)ꢀO(4)
O(1*)ꢀAg(1)ꢀO(2)
O(2)ꢀAg(1)ꢀO(4)
O(3)ꢀAg(1)ꢀO(4)
90.64(4)
146.65(4)
136.43(4)
109.12(4)
61.97(4)
O(1)ꢀAg(1)ꢀO(2)
O(1)ꢀAg(1)ꢀO(5)
O(1*)ꢀAg(1)ꢀO(3)
O(2)ꢀAg(1)ꢀO(5)
O(3)ꢀAg(1)ꢀO(5)
69.61(4)
111.01(5)
128.97(4)
135.63(5)
93.34(5)
ments and crystal data are summarized in Table 1.
Selected bond lengths and angles for the three complexes
are given in Table 2.
the ligand and the counteranions. A broad strong
absorption occurs in the region 1034ꢀ
1254 cmꢂ1 in
/
these complexes, and their peaks are shifted to slightly
different frequencies compared with the normal absorp-
tion of AgClO4 at 1140, 1109, 1087 cmꢂ1. This suggests
that the perchlorate groups in these complexes are
present not as ionic species, but as coordinated ones
[20]. The coordination of silver(I) ions to oxygen,
3. Results
3.1. Syntheses and infrared spectroscopy
carbon or carbonꢀ
also be seen by comparing the spectra of 1ꢀ
/
carbon p bonds of crown ether can
/3 with that
A ligand generally is coordinated to metal ions via a
stoichiometric reaction [4,17], but the complexes pre-
sented here are prepared via reactions of excess metal
ions with the ligand [15]C6, DB[21]C7 and DB[24]C8. In
the experiments, when the molar ratio of metal ions to
ligand is less than 2 for these complexes, it is very
difficult to obtain the single crystals at r.t. The reason
for this phenomenon is twofold, (i) solvent may react
with silver(I) ions to form a complex [18] which
consumes partial silver(I) ions; (ii) when a complex
formed in solution is ‘incongruently saturating’ [19], its
crystal cannot be obtained via a stoichiometric reaction.
The interest in the IR spectra of these compounds lies
mainly in the coordinative interactions associated with
of the three free ligand.
3.2. Description of the structure
3.2.1. Mononuclear complex of
[Ag([15]C6)(ClO4)](THF) (1)
The molecular structure of complex 1 together with
the numbering scheme is shown in Fig. 1. The X-ray
diffraction analysis of 1 reveals a mononuclear complex
of silver(I) located in oxygen base cavity of ligand, and
the uncoordination molecules of THF molecules are
distributed independently in a column in a region of
void space in the lattice interstices. The central silver(I)

M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ
/
118
115
Fig. 1. Molecular structure and atom numbering of 1.
ions, coordinated to six oxygen atoms, is bonded to five
O distances
oxygen atoms from [15]C5 ligand at Agꢀ
/
˚
ranging from 2.402(2) to 2.568(2) A, the last coordina-
tion sites are interestingly completed by one oxygen
atoms from perchlorate group at Agꢀ
/
O distance of
˚
2.515(2)A. Not as other two dibenzo crown ether
ligands in this work, [15]C6 does not offer p-donor
from bezene ring to coordinate to silver(I) ions to form
metalꢀp bond. The steric structure of [15]C6 could be
/
thought of as the one important effect factor. From the
angles data surrounding silver(I) ions with oxygen
atoms from ligand oxygen base cavity, we know that
silver(I) ions positions are slightly over to the oxygen
atoms cavity plane, and are situated in the space of
distorted octahedral geometry.
Fig. 2. Partial labeling (a) and schematic view (b) of silver(I)ꢀ
/
DB[21]C7 dinuclear unit.
work [9], the silver(I) ions in 2 are coordinated to four
oxygens of which three oxygens of ligand and one
hydrate oxygen instead of one perchlorate oxygen in
complex [Ag(DB[18]C6)(ClO4)](THF). The perchlorate
anions are not coordinated to silver(I) ions and only
exist independently of the complex in a column in a
region of void space in the lattice formed by two
dinuclear units (Fig. 3). Above these results, we hope
to obtain new porous complex via using large excess
3.2.2. Dinuclear complex of
[Ag(DB[21]C7)(H2O)]2(ClO4)2 (2)
The unit-cell contents, as determined by the structural
study, showed that the stoichiometry of the complex was
a 1:1:2 metal-to-ligand-to-water tertiary system; how-
ever, molecules of perchlorate anion exist independently
of the complex in lattice interstices. The molecular
structure of 2 together with the atomic numbering
scheme is given in Fig. 2. This compound can be
regarded as both a coordination dimer and a stacking
dimer. The dinuclear complex structure shows each
silver(I) ion is bonded to one hydrate oxygen at Agꢀ
/
O
˚
bond length of 2.310(1) A and three ligand oxygens at
˚
O distance ranging from 2.406(1) to 2.633(2) A,
Agꢀ
/
whereas carbonꢀcarbon p coordination of DB[21]C7
/
with silver(I) in h2-mode and rise to a cavities space with
˚
3.42 A, in which no any molecular is included.
5.62ꢄ
/
The Agꢀ
/
C bond lengths range from 2.598(2) to 2.585(2)
˚
˚
A within the limits from 2.47 to 2.77 A in the reported
silver(I)ꢀaromatic complexes [4,21]. The distance of two
parallel phenyl groups of 3.424 A is very short,
/
˚
indicating presence of strong pꢀp interaction [22].
/
Each DB[21]C7 ligand symmetrically h2-interacts with
one silver(I) ions linked with each other. Similar to
complex [Ag(DB[18]C6)(ClO4)](THF) in our previous
Fig. 3. The view down crystallographic packing of 2.

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M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ118
/
molar ratio between silver salt and ligand, in which ions
as guests locate in the cavity of the polymer network.
This work is underway in our laboratory.
3.4. 1H NMR spectra
The observed 1H NMR chemical shifts of silver(I)
complexes 1ꢀ3 and their free ligands are listed in Table
/
3. The present silver(I) complexes and ligands were
assigned on the basis of previously reports [9,23,24]. As
shown in Table 3, the coordination chemical shifts of
complexes have some changes occur with slightly shifted
to low field comparison with free ligand, in which the
3.3. Dinuclear complex of [Ag2(DB[24]C8)(ClO4)2]
(3)
Fig. 4 depicts a perspective view with atom numbering
of the molecule. Complex 3 is a 2:1:2 metal-to-ligand-to-
anion tertiary system, but without participation of
molecules of solvent in lattice. The crystallographic
studies revealed that the structure contains a dinuclear
core, in which each silver(I) ion is octahedrally coordi-
nated to five oxygen atoms of ligand and one oxygen
atom of the two symmetry related disorder perchlorate
anions. In the unit, each dibenzo-crown ether ligand
host contained two silver(I) ions as guest and a pair of
proton chemical shift of silver(I)ꢀp site is small rela-
/
tively similar to the report 1H NMR data [24]. In 1, from
the comparison with two phenyl groups of free ligand,
the coordination shifts of change of one near oxygen
base cavity (3-H, 4-H) are larger than that of the far one
(1-H). The 1H NMR singnals of the final product 1 were
assigned to the 1-H, NH, 2-H, 3-H, 4-H, 5-H, 6-H and
7-H positions, respectively. The final product is a
mononuclear silver(I) complex.
˚
silver(I) atoms lead to AgÁ Á ÁAg distance of 3.66 A with
4. Discussion
Ag(1)ꢀ
/
O(1)ꢀAg(1*) bond angle of 89.36(4)8. Within
/
unit each silver(I) is bonded to one disorder perchlorate
˚
The three crown ether hosts are coordinated to
silver(I) ions as guest in their oxygen base cavity in
this work. The structure of these silver(I) complexes
display different characteristics with cation being en-
capsulated in an oxygen environment. Complex 1
consists of mononuclear unit with THF being situated
in lattics interstices. Dibenzo-crown ether possess hard
oxygen cavities constructed and soft p-donor benzene
oxygen at Agꢀ
/
O distance of 2.494(2) A and five oxygens
O bond length range from 2.405(1)
of the ligand at Agꢀ
/
˚
to 2.585(1) A. Different from complex 2, silver(I) ions
are not coordinated to phenyl group, whereas silver(I)
ions are coordinated to disorder perchlorate oxygen
lying the symmetry position. Some properties of the
crown ether complex of silver perchlorate have been
reported [6ꢀ9], but its structure remains unknown until
/
rings and subsequently cationꢀ
interaction do occur in the dinuclear silver(I) complexes
2. In 3, there are no cationꢀ
/
p interaction and pꢀp
/
this work. On the other hand, the present structure
differs significantly from that of the reported silver(I)
crown ether complex, where the nuclear complex,
[Ag2(DB[24]C8)(ClO4)2], is based on two symmetry
silver(I) ions coordinated to five oxygens of ligand and
/
p interaction or pꢀp
/
interaction, but two silver(I) ions guests located in the
one oxygen base cavity form the other dinuclear
˚
complex type with AgÁ Á ÁAg distance at 3.66 A, and
related disorder perchlorate without cationꢀ
tion.
/
p interac-
the complex unit shows symmetry structure. The crystal-
lographic results of the present silver(I) complexes
indicated that the structure conformation is prominently
depended on the property of the crown ether ligand.
The average Agꢀ
/
O distances of 2.511, 2.474 and 2.524
˚
A observed for 1, 2 and 3, respectively, are within the
normal range observed in silver(I) carboxylate, oxalate
and crown ether complexes [4,9,17,25,26]. The average
˚
Agꢀ
and fall under 2.40ꢀ
aromatic complexes [27]. In addition, the Agꢀ
/
C distance of 2.585 A in 2 has very closely length
˚
/
2.76 A observed for silver(I)
/O bond
length of silver(I) with hydrate in 2 is shorter than that
of silver(I) with perchlorate group in 1 and 3. It can be
thought that the steric structure and chemical property
of ligand, coordinated molecular groups, silver(I)ꢀp
/
interaction and solvent effect the construction of
silver(I) complexes.
Similar to our previous work [9], complex 2 shows the
silver(I) ions interact with DB[21]C7 ligand at the hard
donor crown ether oxygen atoms and soft donor
Fig. 4. Molecular structure and atom numbering of 3.

M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ
/
118
117
Table 3
Observed 1H NMR chemical shifts of silver(I) complexes and ligands
a
Complex and ligand
d (ppm)
H-1
H-2
H-3
H-4
H-5
H-6
H-7
H-8
NH
Complex 1
[15]O5
8.58
8.55
7.05
6.95
7.15
6.95
7.08
6.90
6.97
6.87
7.04
6.88
7.06
6.89
4.27
4.14
4.34
4.13
6.88
6.76
4.04
3.89
3.93
3.84
4.24
4.07
3.85
3.76
3.81
3.75
4.01
3.83
3.94
3.84
3.87
3.67
3.87
3.67
9.90
9.92
Complex 2
DB[21]O7
Complex 3
DB[24]O8
a
Solvent: CD3COCD3.
benzene ring carbon atoms as well as pꢀ
/
p interaction of
ously demonstrated that the ligand structure and molar
ratio of ligand:metal act as a gate blocking the guest
molecules entering into the host cavity in DB[21]C7
two parallel benzene ring plane in dinuclear unit. The
difference is that silver(I) ions of 2 coordinated to one
hydrate oxygen instead of one perchlorate oxygen in
[Ag(DB[18]C6)(ClO4)](THF). The distance of two par-
system in this work. Further studies of silver(I)ꢀ
/
DB[21]C7 compounds with different silver salts in large
excess molar ratio are currently underway.
˚
allel phenyl at 3.424 A is shorter than that in
˚
[Ag(DB[18]C6)(ClO4)](THF) at 3.531 A, it leads to
stronger pꢀp interaction. The interest in complex 3 is
that two silver(I) ions guests were located in the one
oxygen base cavity to be coordinated to one ligand
/
5. Supplementary material
Complete tables of bond lengths and angels, final
atomic coordinates and equivalent isotropic thermal
parameters, calculated hydrogen atom parameters, ani-
sotropic thermal parameters, and structure factors for
three structures are available from the authors. Details
of the crystal structure determinations of the com-
pounds reported are also available upon request from
the Cambridge Crystallographic Data Center (CCDC),
12 Union Road, Cambridge CB2 1EZ, UK.
without cationꢀ
/
p and pꢀp interaction suggesting that
/
when four and five oxygens of ligand are stereospecifi-
cally coordinated to silver(I) ions, the phenyl groups can
not be coordinated to silver(I) ions. Furthermore, from
the comparison of structures of [Ag(DB[18]C6)-
(ClO4)](THF) [9], [Ag(DB[21]C7)(H2O)]2(ClO4)2 and
[Ag2(DB[24]C8)(ClO4)2], as well known as the ligand
oxygen base cavity size change, the guest number and
coordination fashion are apparently different. When the
ligand includes eight oxygen atoms, two silver(I) ions
locate in one oxygen base cavity of DB[24]C8 to
Acknowledgements
coordinate to oxygen atoms, without silver(I)ꢀ
/
p inter-
action and pꢀp interaction. This indicates that the
/
This work was partially supported by Grants-in-Aid
for Science Research [Nos. 10440201, 11874092,
12440189 and 10016743 (priority area: metal-assembled
complexes)] from the Ministry of Education, Science,
Culture and Sports of Japan.
structure construction process in such dibenzo crown
ether silver(I) complexes system is strongly depend on
the ligand.
In conclusion, with the salt silver perchlorate and
crown ether ligand, three distinct coordination com-
pounds, 1ꢀ
nuclear and two types of dinuclear complexes are shown
in present work. In complex 2 based on cationꢀ
interaction, in particular, the coordination unit involved
both s bonding at an oxygen group and strong pꢀ
bonding between two parallel phenyl groups. There still
are challenges in understanding why silver(I) ions
coordinated to part oxygen atoms of DB[21]C7 and
uncoordinated oxygen atoms have not coordinated to
another silver(I) ions to form one- or two-dimensional
structure. It is believed that self-assembly of crown ether
compounds with transition metal ions can be con-
structed using the stereospecific crown ether as well as
the mole ration and the solvent effect. It is unambigu-
/
3, have been synthesized at r.t. One mono-
References
/
p
[1] E. Weber, F. Vogtle, in: J. Atwood, J. Davies, D. MacNicol, F.
¨
Vogtle (Eds.), Comprehensive Supramolecular Chemistry, vol. 2,
/
p
¨
first ed., Elsevier, Oxford, 1996, pp. 1ꢀ28.
[2] (a) D.A. Dougherty, Science 271 (1996) 163;
/
(b) J.C. Ma, D.A. Dougherty, Chem. Rev. 97 (1997) 1303.
[3] (a) D. Hoffmann, W. Bauer, P.V.R. Schleyer, U. Pieper, D.
Stalke, Organometallics 12 (1993) 1193;
(b) P.J. Dyson, B.F.G. Johnson, C.M. Martin, D. Reed, D.F.
Braga, F. Grepioni, J. Chem. Soc., Dalton Trans. (1995) 4113;
(c) M.A. Pietsch, A.K. Rappe´, J. Am. Chem. Soc. 118 (1996)
10908;
(d) T. Repo, G. Jany, K. Hakala, M. Klinga, M. Plamo, M.
Leskela, B.J. Rieger, J. Organomet. Chem. 549 (1997) 177;
¨

118
M. Wen et al. / Inorganica Chimica Acta 338 (2002) 111ꢀ118
/
(e) M. Munakata, L.P. Wu, G.L. Ning, Coord. Chem. Rev. 198
[14] P.T. Beurskens, G. Admiraal, G. Beurskens, W.P. Bosman, R. de
Gelder, R. Israel, J.M.M. Smits, DIRDIF94, The DIRDIF-94
program system, Technical Report of the Crystallography La-
boratory, University of Nijmegen, Nijmegen, The Netherlands,
1994.
(2000) 171.
[4] M. Munakata, L.P. Wu, T. Kuroda-Sowa, M. Meakawa, S.
Suenaga, K. Sugimoto, Inorg. Chem. 36 (1997) 4903.
[5] I.M. Vezzosi, A.F. Zanoli, L.P. Battaglia, A.B. Corradi, J. Chem.
Soc., Dalton Trans. (1988) 191.
[15] SHELXL-97: G.M. Sheldrick, in: Program for the Refinement of
Crystal Structures, University of Gottingen, Gottingen, Germany,
¨
¨
[6] (a) P.D. Prince, P.J. Cragg, J.W. Steed, Chem. Commun. (1999)
1179;
1997.
[16] TEXSAN: Crystal Structure Analysis Package, Molecular Structure
Corporation, Woodlands, TX, 1985 and 1999.
(b) J.W. Steed, P.C. Junk, B.J. McCool, J. Chem. Soc., Dalton
Trans. (1998) 3417;
[17] M. Munakata, L.P. Wu, T. Kuroda-Sowa, M. Maekawa, Y.
Suenaga, G.L. Ning, T. Kojima, J. Am. Chem. Soc. 120 (1998)
8610.
(c) H. Hassaballa, J.W. Steed, P.C. Junk, M.R.J. Elsegood, Inorg.
Chem. 37 (1998) 4666;
(d) P.D. Prince, J.W. Steed, Supramol. Chem. 10 (1998) 155.
[7] (a) T. Takayanagi, T. Iwachido, S. Motomizu, Bull. Chem. Soc.
Jpn. 71 (1998) 1373;
[18] H.K. Hofsetee, et al., J. Organomet. Chem. 168 (1979) 241.
[19] A.N. Campbell, N.O. Smith, Phase Rule, Dover Publications, Inc,
Mineola, NY, 1951, pp. 348ꢀ349.
/
(b) R.M. Izatt, R.E. Terry, B.L. Haymore, L.D. Hansen, N.K.
Dalley, A.G. Avondet, J.J. Christensen, J. Am. Chem. Soc. 98
(1976) 7620;
[20] B.J. Hathaway, A.E. Underhill, J. Chem. Soc., Dalton Trans.
(1961) 3091.
[21] (a) K. Fukui, A. Imamura, T. Yonezawa, C. Nagata, Bull. Chem.
Soc. Jpn. 34 (1961) 1076;
(c) Y. Takeda, R. Kohno, Y. Kudo, N. Fukada, Bull. Chem. Soc.
Jpn. 62 (1989) 999.
(b) E.A.H. Griffith, E.L. Amma, J. Am. Chem. Soc. 96 (1974)
743.
[8] (a) J.C. Ma, D.A. Dougherty, Chem. Rev. (1997) 1303;
(b) P.D. Beer, M.G.B. Drew, P.A. Gale, P.B. Leeson, M.I. Ogden,
J. Chem. Soc., Dalton Trans. (1994) 3479;
[22] (a) C.A. Hunter, Chem. Soc. Rev. (1994) 101;
(b) C.A. Hunter, J.K.M. Sanfers, J. Am. Chem. Soc. 112 (1990)
5525.
(c) D.A. Hoic, M. Dimare, G.C. Fu, J. Am. Chem. Soc. 119
(1997) 7155;
[23] I. Starke, A. Koch, E. Kleinpeter, H.-J. Holdt, J. Mole. Stru. 356
(1995) 15.
(d) F. Paul, D. Carmichael, L. Ricard, F. Mathey, Angew. Chem.,
Int. Ed. Engl. 35 (1996) 1125.
[24] J.-L. Pierre, P. Baret, P. Chautemps, M. Armand, J. Am. Chem.
Soc. 103 (1981) 2986.
[9] M. Wen, M. Munakata, Y. Suenaga, T. Kuroda-Sowa, M.
Maekawa, Inorg. Chim. Acta, in press.
[25] (a) H. Bock, W. Seitz, M. Sievert, M. Kleine, J.W. Bats, Angew.
Chem., Int. Ed. Engl. 35 (1996) 2244;
[10] (a) M. Munakata, G.L. Ning, T. Kuroda-Sowa, M. Maekawa, Y.
Suenaga, T. Horino, Inorg. Chem. 37 (1998) 5651;
(b) R. Danani, Chem. Eng. News 35 (1957) 5;
(c) D. Braga, F. Grepioni, Chem. Commun. (1996) 571.
[11] SIR88: M.C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo, G.
Polidori, R. Spagna, D. Viterbo, J. Appl. Cryst. 22 (1989) 389-
303.
(b) H. Bock, A. John, Z. Havlas, J.W. Bats, Angew. Chem., Int.
Ed. Engl. 32 (1993) 416;
(c) H. Bock, K. Gharagozloo-Hubmann, C. Nather, N. Nagel, Z.
¨
Havlas, Angew. Chem., Int. Ed. Engl. 35 (1996) 631.
[26] (a) N.O. Bjork, A. Cassel, Acta Chem. Scand., Ser. A 30 (1976)
¨
235;
[12] Fan Hai-Fu, SAPI91, Structure Analysis Programs with Intelligent
Control, Rigaku Corporation, Tokyo, Japan, 1991.
[13] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C.
Giacovazzo, A. Guagliardi, A.G.G. Moliterni, G. Polidori, R.
Spagna, SIR97, J. Appl. Cryst. 32 (1999) 115.
(b) M. Munakata, L.P. Wu, G.L. Ning, T. Kuroda-Sowa, M.
Maekawa, Y. Suenaga, J. Am. Chem. Soc. 121 (1999) 4968.
[27] C. Provent, S. Hewage, G. Brand, G. Bernardinelli, L.J.
Charbonnie´re, A.F. Williams, Angew. Chem., Int. Ed. Engl. 36
(1997) 1287.