Synthesis and crystal structures of silver(I) and copper(II) complexes with p-xylylene-bridged bipyrazolyl ligands

Article abstract of DOI:10.1007/s11243-011-9526-7

Two semi-rigid bipyrazolyl ligands, namely 2,3,5,6-tetramethyl-1,4-bis[(3', 5'-dimethyl-1H -pyrazol-4'-yl)methylene]benzene (H₂L) and 2,3,5,6-tetramethyl-1,4-bis[(3',5'-diphenyl-1H -pyrazol-4'-yl)methylene]benzene (H₂L'), and their A

Full text of DOI:10.1007/s11243-011-9526-7

Transition Met Chem (2011) 36:731–737
DOI 10.1007/s11243-011-9526-7
Synthesis and crystal structures of silver(I) and copper(II)
complexes with p-xylylene-bridged bipyrazolyl ligands
•
Zhao-Yang Wang Jing-Huo Chen
•
•
Ling-Fei Zhao Wen-Hua Zhang Guang Yang
•
Received: 2 July 2011 / Accepted: 1 August 2011 / Published online: 30 August 2011
Ó Springer Science+Business Media B.V. 2011
Abstract Two semi-rigid bipyrazolyl ligands, namely
2,3,5,6-tetramethyl-1,4-bis[(30,50-dimethyl-1H -pyrazol-40-
yl)methylene]benzene (H2L) and 2,3,5,6-tetramethyl-1,4-
bis[(30,50-diphenyl-1H -pyrazol-40-yl)methylene]benzene
(H2L0), and their Ag(I) and Cu(II) complexes have been
prepared and structurally characterized by means of X-ray
analysis. In the structures of the metal complexes, namely
[Ag2(H2L)2](BF4)2ꢀ2H2O (1), [Ag(H2L)(NO3)]n (2),
[Cu2(H2L)4(SO4)2]ꢀ11H2O (3), and {[Ag(H2L0)]BF4}n (4),
the bipyrazoles act as bridging ligands to connect two
metal atoms. Complexes 2 and 4 exhibit 1-D polymeric
structures, while 1 and 3 are discrete molecules with a
rectangular dimer or tetragonal prismatic shapes, respec-
tively. Two different conformations, namely cis and trans,
have been observed for these bipyrazolyl ligands.
series of metallo-macrocycles based on dipalladium cor-
ners [5].
We have recently reported the synthesis and crystal
structures of a semi-rigid m-xylylene-bridged C4-linked
bipyrazolyl ligand as well as its Ag(I) and Cu(II) com-
plexes [6]. As one might expect, the relative orientations
of the two pyrazolyl rings is a key factor to determine
the structure of the metal–bipyrazole complexes. Changes
in the substituents on the central phenyl ring to which
the pyrazolyl units are attached may result in different
spatial arrangements of the two pyrazolyl rings and thus
different structural motifs upon binding to metals. As one
part of our ongoing research on the coordination chem-
istry of bipyrazoles, we report herein the synthesis and
crystal structures of two new p-xylylene-bridged C4-
linked bipyrazolyl ligands (H2L and H2L0, Scheme 1), in
which the pyrazolyl rings are attached to the 1,4-posi-
tions of phenyl ring instead of the 1,3-positions as in our
previous paper, together with three Ag(I) and one Cu(II)
complexes; [Ag2(H2L)2](BF4)2ꢀ2H2O (1), [Ag(H2L)
(NO3)]n (2), [Cu2(H2L)4(SO4)2]ꢀ11H2O (3), and {[Ag(H2L0)]
BF4}n (4). The structural effect of the 3,5-substituents on the
conformations of bipyrazole is discussed in this paper.
Introduction
Bipyrazoles, in which two pyrazolyl units are linked via
covalent bond(s), have recently received much attention [1,
2]. As a type of ligand for metals, they have proven to be
more versatile and flexible in construction of metallo-
supramolecular assemblies than pyrazole itself. Recent
remarkable examples as such include a Cu6 trigonal pris-
matic cage [3], a Cu6 trigonal anti-prismatic cage [4], and a
Results and discussion
Electronic supplementary material The online version of this
article (doi:10.1007/s11243-011-9526-7) contains supplementary
material, which is available to authorized users.
Synthesis and characterization
The bipyrazolyl ligands, H2L and H2L0, were prepared
according to the synthetic route shown in Scheme 1. Both
were characterized spectroscopically by IR (Figs. S5, S8)
and 1H NMR (Figs. S6, S9) spectroscopy. It is worth noting
that beside the strongest parent ion signal, a second strong
Z.-Y. Wang ꢀ J.-H. Chen ꢀ L.-F. Zhao ꢀ W.-H. Zhang ꢀ
G. Yang (&)
Department of Chemistry, Zhengzhou University, 450001
Zhengzhou, China
e-mail: yang@zzu.edu.cn
123

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Transition Met Chem (2011) 36:731–737
Br
O
O
t-BuOK
R
+
R
Br
O
R
NH
R
R
N
O
R
NH2NH2
Fig. 1 Ball-and-stick diagram of the bipyazole H2L. Except for those
bound to N atoms, H atoms are not shown for clarity. Key: N—dotted
ball, C—empty ball, H—smaller empty ball
R
R
N
R
NH
O
i
˚
N–HꢀꢀꢀN hydrogen bonds (N1ꢀꢀꢀN2 = 2.907(2) A, sym-
R
O
metry code: i) -x ? 1, -y ? 1, -z. see Fig. S1).
Scheme 1 Synthetic route for the bipyrazoles (R = Me, H2L;
R = Ph, H2L0)
The complex [Ag2(H2L)2](BF4)2ꢀ2H2O (1) exhibits a
discrete rectangular dimer structure. As shown in Fig. 3, the
Ag(I) atom is linear two-coordinate with two cis-arranged
pyrazolyl groups belonging to different ligands. Each H2L
ligand, in the cis-conformation, acts as a l2 bridge binding to
two Ag(I) atoms. The dihedral angle between the pyrazolyl
signal corresponding to a dimeric species is also present in
the mass spectrum of H2L (Fig. S7).
All the metal complexes were prepared in a straight-
forward way by mixing the appropriate metal salts with
bipyrazoles in solution. The three silver complexes were
obtained in less than 20% yield; higher concentrations of
reactants or faster evaporation/diffusion rates usually
resulted in powdery samples instead of crystals. The IR
spectra of these complexes show the characteristic peaks of
the anions of the metal salts (BF4-, SO42-, NO3-) (Figs.
S10, S11, S12, S13); the presence of these anions was later
verified by X-ray diffraction analysis.
˚
and phenylene rings is 83.7(2) for the bipyrazole ligand in 1.
˚
The intramolecular AgꢀꢀꢀAg distance is 3.4412(3) A, virtu-
ally equal to the sum of the van der Waals radii for the Ag
˚
atoms (3.44 A). Furthermore, the face-to-face distance
between the two nearly parallel pyrazolyl rings of the
˚
adjacent rectangles of 1 is 3.47(1) A, indicative of p–p
stacking interactions (Fig. S2). With the help of the weak
intermolecular interactions of argentophilicity and p–p
stacking, the cations of 1 are joined together to form infinite
puckered chains, which are in turn further interconnected via
Crystal structure descriptions
Both bipyrazoles crystallize in space group P21/c. In their
asymmetric units, only half of the molecule is independent,
being related to the other half by an inversion center. As
depicted in Figs. 1 and 2, in their crystals, both ligands
adopt the trans-conformation; the two pyrazolyl groups are
located on the opposite sides of the central phenylene ring
(Scheme 2). The dihedral angles between pyrazolyl and
0
˚
phenylene rings are 84.5(6) and 86.7(2) for H2L and H2L ,
˚
respectively. Intramolecular C–Hꢀꢀꢀp interactions may exist
0
˚
in H2L , as evident by the distance of 2.5293(4) A from the
peripheral phenyl H-atom to the central phenylene ring
(Fig. 2). On the other hand, no such interactions can be
found for H2L. This observation implies that H2L might be
more flexible than H2L0, because the absence of the phe-
nyl–phenyl interaction makes the rotation along C4(pz)–
C(–CH2–) or C(–CH2–)–C(Ph) much easier for the former.
In its crystal, molecules of H2L0 are linked into zigzag
chains running along the a-axis, by pairs of complementary
Fig. 2 Ball-and-stick diagram of H2L0. Except for the H atoms bound
to N atoms and the phenyl H atoms closest to the central phenylene, H
atoms are not shown for clarity. The dashed lines stand for the C–
Hꢀꢀꢀp interactions existing in H2L0. Key: N—dotted ball, C—empty
ball, H—smaller empty ball
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Transition Met Chem (2011) 36:731–737
733
this time yields 1D structures of MnLn type, running along
NH
N
the c-axis. The dihedral angle between the pyrazolyl and
˚
phenylene rings is 87.9(3) for the bipyrazole ligand in 2.
NH
N
N
NH
Interestingly, the shape of the chain looks rather like a
‘‘square wave’’ when viewed down the b-axis. It is note-
worthy that the structural parameters (e. g. the coordination
geometry around metal, bond distances, and angles) of the
complex cations in 1 and 2 are very similar, and therefore,
they represent an example of supramolecular ‘‘ring-open-
ing’’ isomerism between 0D cyclic M2L2 metallacyclic and
1D MnLn polymeric motifs [8]. As discussed by Su, some
subtle factors such as solvent or anion may play an
important role in determining which structural form,
among several possible motifs, will be crystallized out
from the solution [7].
N
HN
cis
trans
Scheme 2 Two possible conformations of bipyrazoles H2L and H2L0
The complex [Cu2(H2L)4(SO4)2]ꢀ11H2O (3) is a discrete
molecular cage. The Cu(II) atom exhibits square pyramidal
coordination geometry, with four pyrazolyl N atoms from
four bipyrazoles as the base and one O atom of sulfate as
the apex. The ligand, again in its cis-conformation, acts as
a bridge linking two Cu(II) atoms (Fig. 5). Thus, the con-
nection of four bipyrazoles by two Cu(II) atoms results in a
square prismatic cage. The dihedral angle between the
˚
pyrazolyl and phenylene rings is 88.7(2) for the ligand in 3.
In a recent review, design approaches have been proposed
for discrete coordination assemblies based on non-rigid
ligands, of which the strategy of ‘‘molecular clips ? metal
ions of Cn symmetry’’ can be used to predict and explain
the structures of the convergent assemblies including M2L2
metallacycles and M2L4 tetragonal prisms as reported here
and in our previous paper, with the semi-rigid bipyrazoles
in cis-conformation acting as ‘‘molecular clips’’ and Ag(I)/
Cu(II) ions as connectors of C2 or C4 symmetry, respec-
tively [7].
Fig. 3 Ball-and-stick diagram of the [Ag2(H2L)2]2? cation of complex
1 with atom labels, showing the coordination environment around the
Ag atoms and the cis-conformation of the l2-bridging ligand. Selected
˚
distances (A) and angles (°): Ag1–N1 = 2.105(3), Ag1–N3a =
The complex {[Ag(H2L0)](BF4)}n (4) exhibits a 1D
structure. The Ag(I) atom is linearly two-coordinated by
two cis-placed pyrazolyl groups from two adjacent ligands.
Unlike the methyl-substituted bipyrazoles in complexes 1,
2, and 3, the phenyl-substituted ligand in complex 4 adopts
a trans-conformation and acts as a bridge linking two
Ag(I) atoms to form zigzag chains (Scheme 2, Fig. 6). The
chain incorporate the Npz–HꢀꢀꢀF H-bonds, which may fur-
ther consolidate the infinite structure (N3ꢀꢀꢀF3 = 2.764
2.114(3); N1–Ag1–N3a = 173.76(13). Symmetry codes: (a) -x,
-y ? 1, -z ? 1. Except for the H atoms bound to N atoms, other H
atoms are not shown for clarity. Key: N—dotted ball, C—empty ball,
H—smaller empty ball, Ag—cross hatched ball
Npz–HꢀꢀꢀF hydrogen bonds to form planes (N2ꢀꢀꢀF3i
ii
˚
˚
= 2.809(4) A, N4ꢀꢀꢀF4 = 2.953(5) A. Symmetry codes:
(i) x-1, y ? 1, z; (ii) x ? 1, y, z. Fig. S3). It is observed that
in the crystal structure of 1, there are channels along the
a-axis, in which solvent water molecules reside (Fig. S4).
A few similar rectangular dimetallomacrocycles based on
various metals and ligands are also known in the literature
[6, 7].
˚
˚
˚
(4) A, N4ꢀꢀꢀF1 = 2.838(5) A, N4ꢀꢀꢀF2 = 3.262(5) A). The
face-to-face distance and dihedral angle between the cen-
tral phenylene ring and the 3(5)-phenyl rings of the same
˚
ligand are ca 3.5 A and 10.6(1)°, 18.7(3)°, 25.1(1)°,
The complex {[Ag(H2L)](NO3)}n (2) exhibits a 1-D
chain structure. The Ag(I) atom is linearly coordinated by
two trans-placed pyrazolyl groups from two adjacent
ligands (Fig. 4). The bipyrazole also adopts a cis-confor-
mation and acts as a bridge linking two Ag(I) atoms, as in
complex 1 (Scheme 2). However, assembly of these units
37.34(1)°, respectively, which indicates the existence of p–
p stacking interactions. As shown in Fig. 6, the most
prominent feature of this structure is the presence of a triad
of stacking phenyl rings. Obviously, this kind of phenyl–
phenyl interaction favors the trans-conformation since the
geometry of this ligand does not allow two phenyl
123

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Transition Met Chem (2011) 36:731–737
Fig. 4 Ball-and-stick diagram of the [Agn(H2L)n]n? unit of complex
2 with atom labels, showing the coordination environment around the
Ag atoms and the cis-conformation of the l2-bridging ligand.
N1a = 2.132(4); N1a–Ag–N1 = 173.3(3). Symmetry codes: (a) x,
-y ? 1/2, -z ? 1/4. Except for the H atoms bound to N atoms, other
H atoms are not shown for clarity. Key: N—dotted ball, C—empty
ball, H—smaller empty ball, Ag—cross hatched ball
˚
Selected distances (A) and angles (°): Ag1–N1 = 2.132(4), Ag1–
Conclusion
We have described in this paper the synthesis and crystal
structures of two semi-rigid p-xylylene-bridged C4-linked
bipyrazolyl ligands and their Ag(I) and Cu(II) complexes.
Compared to our previously reported m-xylylene-bridged
bipyrazoles, the p-xylylene-bridged analogs have different
spatial arrangement for the two pyrazolyl rings and therefore
different coordination chemistry. The 3,5-substituents of the
pyrazole can be an important structural determinant in dic-
tating the cis- or trans-conformations of the bipyrazoles.
From the present structural study, we can see phenyl–phenyl
interactions lead to the preference for trans-conformation of
3,5-diphenyl substituted bipyrazole (H2L0), as observed in
the structures of the Ag(I) complex and the free ligand. On
the other hand, 3,5-dimethyl substituted bipyrazole (H2L)
exhibits greater flexibility in switching between two possi-
ble conformations, due to lack of such phenyl–phenyl
interactions.
Fig. 5 Ball-and-stick diagram of complex 3, with atom labels, showing
the coordination environment around the Cu atoms and the cis-
conformation of the l2-bridging ligand. All the methyl groups and H
˚
atoms are omitted for clarity. Selected distances (A) and angles (°):
Cu1–N8a = 1.961(5), Cu1–N5 = 1.969(6), Cu1–N3a = 2.023(5),
Cu1–N1 = 2.042(5), Cu1–O4 = 2.210(5); N8a–Cu1–N5 = 88.3(2),
N8a–Cu1–N3 = 171.00(18), N5–Cu1–N3a = 92.1(2), N8a–Cu1–
N1 = 89.2(2), N5–Cu1–N1 = 173.9(2), N3a–Cu1–N1 = 89.5(2),
N8a–Cu1–O4 = 95.2(2), N5–Cu1–O4 = 94.7(2), N3a–Cu1–O4 =
93.8(2), N1–Cu1–O4 = 91.0(2). Symmetry codes: a) -x ? 1, y,
-z. Key: N—dotted ball, C—empty ball, Cu—cross hatched ball,
S—hatched ball, O—smaller hatched ball
Experimental
The CHN microanalyses were obtained with a Flash EA
1112 elemental analyzer. IR spectra (KBr pellets) were
substituents to stack at the same side of the central phe-
nylene ring. It is interesting to note that the phenyl–phenyl
interaction shows itself in the form of p–p stacking in 4,
instead of the C–Hꢀꢀꢀp interaction seen in the free ligand. In
this sense, the trans-conformation observed in complex 4 is
actually inherited from the phenyl-substituted bipyrazole
and manifests itself rather differently in its Ag(I) complex.
Hanton et al. reported a ‘‘three-layered’’ p-stacked ligand,
namely 2,3-bis(60-methyl-20-pyridylmethylsulfanylmethyl)
pyrazine, which was found to function, via intramolecular
p stacking, as an exo-ditopic bridge upon binding to
Ag(I) atoms [9]. This complex, together with our present
work, suggests that the relatively weaker phenyl–phenyl, or
more generally aromatic–aromatic interactions can be used
to control the geometry of a ligand by delicate design.
1
recorded on a Niclolet Impact 420 FTIR spectrometer. H
NMR spectra were recorded on a Bruker Avance 400 MHz
spectrometer. Mass spectra were obtained with an Agilent
1100 series LC/MSD Trap XCT ion trap mass spectrometer.
2,3,5,6-tetramethyl-1,4-bis(bromomethyl)benzene was pre-
pared by a literature method [10]. All other reagents were
obtained commercially and used as received.
Preparation of 2,3,5,6-tetramethyl-1,4-bis[(30,50-
dimethyl-1H-pyrazol-40-yl)methylene] benzene (H2L)
Potassium (0.59 g, 15 mmol) was dissolved in tert-butyl
alcohol (60 mL). To the solution, pentane-2,4-dione (1.80 g,
18 mmol), 2,3,5,6-tetramethyl-1,4-bis(bromomethyl)benzene
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Transition Met Chem (2011) 36:731–737
735
Fig. 6 Ball-and-stick diagram
of the [Agn(H2L’)n]n? unit of
complex 4 with atom labels,
showing the coordination
environment around the Ag
atoms and the trans-
conformation of the l2-bridging
ligand. Only N-bound H atoms
are shown. The dashed lines
denote the relative weak forces
such as H-bonds or p–p stacking
interactions. Selected distances
˚
(A) and angles (°): Ag1–
N1 = 2.108(2), Ag1–
N2 = 2.118(3), N1–Ag1–
N2 = 168.43(11). Key: N—
dotted ball, C—empty ball, H—
smaller empty ball, Ag—cross
hatched ball, F—hatched ball
(2.40 g, 7.5 mmol), and KI (0.34 g) were added succes-
sively. The mixture was stirred under nitrogen for 3 days,
and then tert-butyl alcohol was distilled off. The residue was
dissolved in CH2Cl2, and the solution was washed with
water, dried over MgSO4, and evaporated to dryness to
obtain the bis-diketone—3,30-(2,3,5,6-tetramethyl-1,4-phe-
nylene)bis(methylene)dipentane-2,4-dione as a white solid.
This bis-diketone was dissolved in chloroform (50 mL), and
a solution of N2H4ꢀH2O (0.75 g, 15 mmol) in methanol
(5 mL) was added slowly. The mixture was stirred at 50 °C
for 12 h, then the solvent was distilled off, and the residue
was washed with water. The crude product was recrystallized
from ethanol to afford colorless needles of H2L. Yield: 2.4 g,
90%.
dissolved in chloroform (50 mL), and a solution of
N2H4ꢀH2O (0.75 g, 15 mmol) in methanol (5 mL) was
added slowly. The mixture was stirred at 50 °C for 12 h,
then the solvent was distilled off, and the residue was
washed with aqueous methanol to afford the crude product,
which was recrystallized from THF to yield colorless
blocks of H2L. Yield: 3.8 g, 85%.
C42H38N4 (598.78) Found C 84.3, H 6.4, N 9.3; Calcd. C
1
84.3, H 6.4, N 9.4. HNMR (400 MHz, CDCl3): d = 1.60
(s, 12H, CH3–), 3.88 (s, 4H, –CH2–), 7.13–7.26 (m, 20H,
Ph–H) ppm. IR (KBr): m = 3,228s, 3,056w, 3,021w,
2,947w, 1,605w, 1,561s, 1,491m, 1,434m, 1,253m, 1,221m,
1,134w, 970w, 768 m, 700 s cm-1
.
C22H30N4 (350.50) Found C 74.5, H 8.7, N 16.0; Calcd.
1
C 75.4, H 8.6, N 16.0. HNMR (400 MHz, DMSO-d6):
Preparation of [Ag2(H2L)2](BF4)2ꢀ2H2O (1)
d = 1.78 (s, 12H, CH3–Ph), 2.09 (s, 12H, CH3–pz), 3.70 (s,
4H, –CH2–) ppm. IR (KBr): m = 3,170s, 3,117s, 3,066m,
3,006w, 2,915s, 2,917s, 2,865s, 1,637w, 1,579 m, 1,515w,
1,464s, 1,411m, 1,379w, 1,298s, 1,199m, 1,157s, 1,053s,
1,009s, 829m, 794w, 744 m cm-1. MS: m/z = 351.1
[M ? H]?, 701.5 [M2 ? H]?.
A solution of AgBF4 (1.9 mg, 0.01 mmol) in acetonitrile
(2 mL) was added to a solution of H2L (3.5 mg,
0.01 mmol) in ethanol (2 mL). The resulting solution was
allowed to evaporate for several days to afford colorless
crystals in 15% (0.8 mg) yield.
C44H60N8Ag2B2F8ꢀ2H2O (1,124.33) Found C 47.0, H
5.6, N 10.3; Calcd. C 47.0, H 5.7, N 10.0. IR (KBr):
m = 3,321 s, 2,919 s, 1,573 m, 1,522w, 1,438 m, 1,417 m,
1,383 m, 1,290 m, 1,184 s, 1,083 s (BF4-), 1,040 s
Preparation of 2,3,5,6-tetramethyl-1,4-bis[(30,50-
diphenyl-1H-pyrazol-40-yl)methylene] benzene (H2L0)
(BF4-), 918 m, 694 m cm-1
.
Potassium (0.59 g, 15 mmol) was dissolved in tert-butyl
alcohol (60 mL). To the solution, dibenzoylmethane
(4.10 g, 18 mmol), 2, 3, 5, 6-tetramethyl-1,4-bis(bromo-
methyl)benzene (2.40 g, 7.5 mmol), and KI (0.34 g) were
added successively. The mixture was stirred under nitrogen
for 3 days and then sucked under vacuum. The filter resi-
due was washed successively with water and methanol and
dried overnight in the air. The obtained bis-diketone was
Preparation of [Ag(H2L)(NO3)]n (2)
A solution of AgNO3 (1.7 mg, 0.01 mmol) in methanol
(2 mL) was added to a solution of H2L (3.5 mg,
0.01 mmol) in ethanol (2 mL). The resulting solution was
allowed to evaporate for 1 week to afford colorless crystals
in 20% (1.1 mg) yield.
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Transition Met Chem (2011) 36:731–737
Table 1 Crystallographic data
H2L0
1
2
4
Formula
Mr
C42H38N4
598.78
C22H32AgBF4N4O
563.20
C22H30AgN5O3
520.38
C46H46AgBF4N4O
865.55
Crystal size
(mm3)
0.42 9 0.36 9 0.13 0.30 9 0.25 9 0.20 0.30 9 0.26 9 0.24 0.32 9 0.23 9 0.19
Crystal system
Space group
Monoclinic
P21/c
Triclinic
P-1
Tetragonal
I-42d
Triclinic
P-1
˚
a (A)
13.643 (3)
13.343 (3)
9.3064 (19)
90
9.070 (3)
11.267 (4)
14.919 (5)
69.376 (3)
79.445 (3)
67.815 (3)
1319.0 (7)
2
17.523 (3)
17.523 (3)
16.220 (5)
90
9.9614 (8)
13.0003 (11)
17.5849 (15)
69.8620 (10)
86.3710 (10)
73.5370 (10)
2048.9 (3)
2
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
103.65 (3)
90
90
90
3
˚
V (A )
1646.3 (6)
2
4980.3 (18)
8
Z
T (K)
298
298
298
298
Dcalcd (Mg/m3) 1.208
1.418
1.388
1.403
l (mm-1
)
0.071
0.812
0.840
0.551
F(000) (e)
hkl range
636
576
2,144
892
-11 B h B 18
-16 B k B 17
-12 B l B 12
12,601
-10 B h B 10
-13 B k B 13
-17 B l B 18
8,807
-23 B h B 21
-23 B k B 23
-21 B l B 21
18,745
-13 B h B 13
-17 B k B 17
-23 B l B 23
18,646
Refl. Collected
Refl. Unique
3,983
4,742
3,079
9,867
(Rint = 0.0336)
210
(Rint = 0.0305)
306
(Rint = 0.0690)
146
(Rint = 0.0252)
518
Param. refined
Restraints
0
2
0
5
Final R indices R1 = 0.0578
R1 = 0.0536
wR2 = 0.1755
1.065
R1 = 0.0591
wR2 = 0.1627
1.102
R1 = 0.0541
wR2 = 0.1370
1.031
[I [ 2r(I)]
GoF (F2)
wR2 = 0.1554
1.046
Dqfin (max,
0.517, -0.462
1.776, -0.849
1.362, -0.573
0.821, -0.615
-3
˚
min) e A
Preparation of {[Ag(H2L0)]BF4}n (4)
C22H30N5AgO3ꢀH2O (537.15) Found C 49.4, H 6.0, N
12.8; Calcd. C 49.2, H 6.0, N 13.0. IR (KBr): m = 3,189s,
3,082m, 2,919s, 1,578m, 1,334s (NO3-), 1,320s (NO3-),
A solution of AgBF4 (1.9 mg, 0.01 mmol) in acetonitrile
(1 mL) was layered on the surface of a solution of H2L0
(6.0 mg, 0.01 mmol) in THF (3 mL) in a test tube. Colorless
crystals were obtained in 15% (1.2 mg) yield within several
days.
1,188m, 1,056m, 1,039w, 1,013m, 825w cm-1
.
Preparation of [Cu2(H2L)4(SO4)2]ꢀ11H2O (3)
C42H38N4AgBF4 (793.45) Found C 63.6, H 4.8, N 7.0;
Calcd. C 63.6, H 4.8, N 7.1. IR (KBr): m = 3,290s, 3,058w,
2,962w, 1,604w, 1,561m, 1,490s, 1,444s, 1,243m, 1,227m,
1,182s, 1,124s, 1,084s (BF4-), 1,061s (BF4-), 1,028s,
A solution of H2L (3.5 mg, 0.01 mmol) in ethanol (2 mL)
was layered on the surface of an aqueous solution of
CuSO4ꢀ5H2O (5.0 mg, 0.02 mmol) in a test tube. Dark blue
crystals were obtained in 70% (3.4 mg) yield within sev-
eral days.
970s, 777m, 754m, 697 s cm-1
.
C88H142N16Cu2S2O19 (1,919.39) Found C 54.6, H 7.0, N
11.6, S 3.3; Calcd. C 55.1, H 7.5, N 11.7, S 3.3. IR (KBr):
m = 3,420m, 3,237s, 3,083w, 2,924s, 2,762w, 1,637m,
1,577m, 1,526w, 1,440s, 1,383m, 1,315m, 1,291w, 1,184s
(SO42-), 1,142s (SO42-), 1,109s (SO42-), 1,054s (SO42-),
X-ray crystallography
Diffraction intensities were collected on a Bruker Apex II
CCD diffractometer with graphite-monochromated Mo-Ka
˚
radiation (0.71,073 A). Absorption corrections were applied
974w, 803w, 615 m cm-1
.
123

Transition Met Chem (2011) 36:731–737
737
Acknowledgments This work has been supported by the NSF of
China (21071126). WZY also acknowledges a research grant from the
Graduate School of Zhengzhou University.
using the multiscan program. The structures were solved by
direct methods and refined by least squares techniques using
the SHELXS-97 and SHELXL-97 programs [11]. All non-
hydrogen atoms were refined with anisotropic displacement
parameters; hydrogen atoms were generated geometrically.
In complex 3, one S atom and two O atoms have been split
into two parts with an occupancy factor of 0.5 due to the
disorder of the sulfates.
References
1. Viciano-Chumillas M, Tanase S, de Jongh LJ, Reedijk J (2010)
Eur J Inorg Chem 3403–3418
2. Halcrow MA (2009) Dalton Trans 2059–2073
3. Gao GF, Li M, Zhan SZ, Lv Z, Chen GH, Li D (2011) Chem Eur
J 17:4113–4117
4. Jozak T, Sun Y, Schmitt Y, Lebedkin S, Kappes M, Gerhards M,
Thiel WR (2011) Chem Eur J 17:3384–3389
5. Ning GH, Yao LY, Liu LX, Xie TZ, Li YZ, Qin Y, Pan YJ, Yu
SY (2010) Inorg Chem 49:7783–7792
6. Yang G, Hao SJ, Wang ZY (2010) Transition Met Chem
35:381–386
7. Chen CL, Zhang JY, Su CY (2007) Eur J Inorg Chem 2997–3010
8. Chen CL, Yu ZQ, Zhang Q, Pan M, Zhang JY, Zhao CY, Su CY
(2008) Cryst Growth Des 8:897–905
9. Caradoc-Davies PL, Hanton LR (2001) Chem Commun
1098–1099
10. van der Made AW, van der Made RH (1993) J Org Chem
58:1262–1263
11. Sheldrick GM (2008) Acta Cryst A64:112–122
Crystal data for H2L0, 1, 2, and 4 are summarized in
Table 1. Because of the poor quality of crystal data of
H2L and 3, only a preliminary structure analysis was
carried out. However, the stoichiometry and heavy
atom positions were unequivocally determined. For
H2Lꢀ2MeOH: C22H30N4ꢀ2CH3OH, monoclinic P21/c, a =
˚
15.825(3), b = 5.2397(10), c = 15.519(3) A, b =
3
˚
˚
108.97(3), V = 1,217.0(4) A , S = 1.363, R1 = 0.2781
for 2,389 reflections with I [ 2r(I) and 143 parameters.
For 3: C88H140Cu2N16O18S2, monoclinic C2, a =
˚
22.133(8), b = 19.368(4), c = 15.831(3) A, b =
3
˚
118.21(2)°, V = 5,980(3) A , S = 1.181, R1 = 0.1353
for 7,230 reflections with I [ 2r(I) and 595 parameters.
CCDC 821902—821905 contain the supplementary
crystallographic data for H2L0, 1, 2, and 4. These data can
be obtained free of charge from The Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
123