Hydrothermal syntheses and crystal structures of two 4,4′- biphenyldicarboxylate copper(II) complexes with 1,10-phenanthroline

Article abstract of DOI:10.1016/j.molstruc.2004.05.012

Two structurally diverse compounds, [Cu(Hbpdc)₂(phen)] (1) and [Cu(bpdc)(phen)(H₂O)]_n (2) (H₂bpdc=4,4′- biphenyldicarboxylic acid, phen=1,10-phenanthroline), were synthesized under hydrothermal conditions. Copper atom in 1 is four-coordinated to one bidentate phen ligand and two monodentate partly deprotonated 4,4′- biphenyldicarboxylates. As expected, the structure of 1 is a monomeric species and affords an extended two-dimensional hydrogen bonding architecture. Each copper atom in 2 is five-coordinated to one phen, one water molecule, and two bis-monodentate fully deprotonated 4,4′-biphenyldicarboxylates. Therefore, the structure of 2 is a one-dimensional chain.

Full text of DOI:10.1016/j.molstruc.2004.05.012

Journal of Molecular Structure 699 (2004) 101–104
www.elsevier.com/locate/molstruc
Hydrothermal syntheses and crystal structures of two 4,40-
biphenyldicarboxylate copper(II) complexes with 1,10-phenanthroline
*
Shu-Yan Zhang, Ming-Xin Yu, Long-Guan Zhu
Department of Chemistry, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
Received 21 April 2004; revised 15 May 2004; accepted 17 May 2004
Abstract
Two structurally diverse compounds, [Cu(Hbpdc)2(phen)] (1) and [Cu(bpdc)(phen)(H2O)]n (2) (H2bpdc ¼ 4,40-biphenyldicarboxylic acid,
phen ¼ 1,10-phenanthroline), were synthesized under hydrothermal conditions. Copper atom in 1 is four-coordinated to one bidentate phen
ligand and two monodentate partly deprotonated 4,40-biphenyldicarboxylates. As expected, the structure of 1 is a monomeric species and
affords an extended two-dimensional hydrogen bonding architecture. Each copper atom in 2 is five-coordinated to one phen, one water
molecule, and two bis-monodentate fully deprotonated 4,40-biphenyldicarboxylates. Therefore, the structure of 2 is a one-dimensional chain.
q 2004 Elsevier B.V. All rights reserved.
Keywords: Hydrogen bonding; Crystal structure; Copper complex; Diversity; Polymer
1. Introduction
acid (0.048 g, 0.2 mmol), and 1,10-phenanthroline (0.080 g,
0.4 mmol) in an aqueous solution (8 ml) was sealed in a 25 ml
stainless-steel reactor with Teflon liner, then heated to 120 8C
and kept at this temperature for 24 h. Blue block crystals were
obtained after being cooled to room temperature. Anal. Calc.
For C40H26CuN2O8: C, 66.16; H, 3.61; N, 3.86%. Found: C,
66.32; H, 3.57; N, 3.94%.
Structural or framework diversity of coordination
polymers is currently under intensive studies due to the
important relationship between structures and properties
[1–3]. Many successful examples of structural diversity
have been achieved in the syntheses of benzenedicarbox-
ylate complexes [4–8]. Recently, 4,40-biphenyldicarboxylic
acid (H2bpdc), which is a longer rigid spacer, has attracted
attention to construct novel coordination polymers with
potential applications as functional materials [9–13].
Here, we represent two copper complexes of 4,40-biphe-
nyldicarboxylate complexes with partly and fully
deprotonated ligands, namely [Cu(Hbpdc)2(phen)] (1) and
[Cu(bpdc)(phen)(H2O)]n (2).
A similar procedure was used for preparation of
compound 2. A mixture of Cu(CH3COO)2·H2O (0.040 g,
0.2 mmol), 4,40-biphenyldicarboxylic acid (0.048 g,
0.2 mmol), and 1,10-phenanthroline (0.040 g, 0.2 mmol),
sodium hydroxide (0.012 g, 0.3 mmol), and water (8 ml)
was sealed in a 25 ml stainless-steel reactor with Teflon
liner and heated at 140 8C for 24 h. After cooling, blue block
crystals of compound 2 were filtrated and dried in vacuum.
Anal. Calc. For C26H18CuN2O5: C, 62.21; H, 3.61; N,
5.58%. Found: C, 61.97; H, 3.70; N, 5.68%.
The two carboxylic protons of H2bpdc have different
acidity values. The unprecedented compound 1 involves the
first deprotonated state of Hbpdc2. Under hydrothermal
condition using aqueous NaOH solution, we expect the
proton on Hbpdc2 to be easily deprotonated and thus
compound 2 was synthesized. This strategy allows us to
create different structure topologies.
2. Experimental
2.1. Synthesis and IR spectra
For the preparation of compound 1, a mixture of Cu(CH3
COO)2· H2O (0.040 g, 0.2 mmol), 4,40-biphenyldicarboxylic
The IR spectra of compounds 1 and 2 display the
asymmetric and symmetric stretching vibrations of the
carboxylate groups at 1546, 1426, and 1389 cm21 for
*
Corresponding author. Tel.: þ86-57187963867; fax: þ86-
57187951895.
E-mail address: chezlg@zju.edu.cn (L.-G. Zhu).
0022-2860/$ - see front matter q 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2004.05.012

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S.-Y. Zhang et al. / Journal of Molecular Structure 699 (2004) 101–104
Table 1
Crystal data and details of structural determination of compounds 1 and 2
Formula
C40H26CuN2O6
C26H18CuN2O5
Fw
726.17
501.965
Crystal color, shape
Crystal size (mm3)
Space group
˚
a (A)
˚
b (A)
Blue, block
0.26 £ 0.25 £ 0.19
Monoclinic (C2/c)
12.9262(5)
24.4718(10)
10.0004(4)
90
Blue, block
0.50 £ 0.18 £ 0.14
Monoclinic (P21/n)
14.599(4)
9.764(2)
16.936(4)
90
˚
c (A)
a (deg)
b (deg)
g (deg)
90.443(2)
90
95.581(5)
90
3
˚
V (A )
3163.3(2)
1.525
2402.6(10)
1.388
D (Mg/cm23
)
T (K)
m (mm21
293 ^ 2
0.753
293 ^ 2
0.953
)
Measured reflections
Independent reflections
Observed reflections
R1 and wR2 ðI . 2sðIÞÞ
R1 and wR2 (all data)
Number of variables
Goodness-of-fit (GOF)
Largest difference peak
8420
13387
2859
5073
2859
5073
0.055, 0.130
0.059, 0.132
231
0.069, 0.185
0.121, 0.202
325
1.133
0.982
0.470, 20.355
0.980, 20.484
Fig. 1. ORTEP view of compound [Cu(Hbpdc)2(phen)] (1).
23
˚
and hole (e A
)
˚
˚
1.922(2) A for Cu–O and 1.989(2) A for Cu–N (Table 2).
Atoms of N1, O2, N1* (symmetry code: 2 2 x, y, 1/2 2 z),
and O2* consist of a square planar geometry with the
rms ¼ 0.1646, indicating some deviations from perfect
square plane. Each Hbpdc2 ligand affords one deprotonated
carboxylate and one carboxylic group, leading to a single
negative charge on the ligand. The coordination behavior of
the deprotonated carboxylate group results in a larger
dihedral angle [22.73(39)8] between deprotonated
carboxylate group and its connected benzene ring as
compared with the smaller dihedral angle [8.94(11)8]
between the carboxylic group and its attached benzene
ring. The dihedral angles of two benzene rings and
between deprotonated carboxylate group and
carboxylic group for one Hbpdc2 ligand are 47.29(10)8 and
77.44(28)8, respectively, indicating some flexible nature of
the Hbpdc2 ligand.
compound 1 and 1543, 1426, and 1382 cm21 for compound
2, respectively. The strong absorption at 1708 cm21 in
compound 1 is in agreement with a carboxylic group, while
in compound 2 no absorption peak of any protonated ligand
(1680–1730 cm21) confirms completely deprotonation of
H2bpdc by sodium hydroxide.
2.2. Single crystal structure determination
Crystals with dimensions of 0.26 mm £ 0.25 mm £ 0.19
mm for compound 1 and 0.50 mm £ 0.18 mm £ 0.14 mm
for compound 2 were carefully selected and mounted on a
Bruker Smart CCD area detector with graphite
˚
monochromatized Mo Ka radiation (l ¼ 0:71073 A).
An empirical absorption correction was applied using the
SADABS program [14]. The structures were solved by direct
methods using SHELXS-97 [15] and refined by least-squares
procedures on F02 with SHELXL-97 [16] in the WinGX
environment [17]. Crystal data and structure refinements are
given in Table 1.
It is worth noting that the hydroxyl group forms
hydrogen bond with uncoordinated oxygen atom (O1) and
the hydrogen bond length of O1· · ·O4* distance is 2.6260
˚
(34) A, thus the structure is assembled into 2D hydrogen
bonding network (Fig. 2). The hydrogen bonding interaction
made the structure more stable.
3. Results and discussion
Table 2
Compound 1 consists of a mononuclear CuII complex and
has two-fold symmetry (Fig. 1). The molecule displays a
square planar geometry and atom Cu1 is coordinated by two
oxygen atoms of two monodentate carboxylate groups and
two nitrogen atoms of one 1,10-phenanthroline ligand.
Distances associated with the coordination sphere are
Selected bond lengths and angles for compound 1
Cu1–O2
1.922(2)
Cu1–N1
1.989(2)
O2–Cu1–N1
O2–Cu1–O2*
93.0(1)
92.7(2)
O2–Cu1–N1*
N1–Cu1–N1*
169.2(1)
83.0(1)
Symmetry code: *, 2 2 x, y, 1/2 2 z.

S.-Y. Zhang et al. / Journal of Molecular Structure 699 (2004) 101–104
103
In compound 2, the copper center is five-coordinated
and is a square pyramidal geometry (Fig. 3). Atoms of
O1, O5, N1, and N2 are sitting in the basal plane, while
the atom O4# (symmetry code: 1/2 þ x, 21/2 þ y, z)
occupies the apical position. The copper center coordi-
nates to two monodentate oxygen atoms of two bpdc22
ligands in the cis positions with Cu–O distances of
˚
1.931(4) and 2.267(4) A (Table 3). The other three sites
are occupied by one terminal water with a Cu–O
˚
distance of 1.963(3) A and by 1,10-phenanthroline with
22
˚
Cu–N distances of 2.015(4) and 2.025(5) A. The bpdc
in compound 2 is coordinated to metal ions as bis-
monodentate mode, so that the structure is extended into
one-dimensioanl zig-zag chain with the Cu· · ·Cu
22
˚
separation of 15.473(2) A by bpdc
linkage (Fig. 4).
Fig. 2. Two-dimensional hydrogen bonding network view of (1).
Phenanthroline ligands and H atoms were deleted for clarity.
The dihedral angle between two rings of bpdc22 is
24.76(39)8, indicating some torsion, while the carboxylate
has a nearly co-planar with the benzene ring.
Framework diversity in the system of Cu2þ/bpdc/phen
is interesting. Besides above two compounds, a tetra-
nuclear compound, [Cu4(bpdc)4(phen)4(H2O)2](2H2O) (3),
with fully deprotonated ligand based on the system of
Cu2þ/bpdc/phen, was synthesized [18]. The synthetic
strategy of compound 3 is similar to that of 2 except
triethylamine used in the synthesis of 3. A close look at
the crystal structures of 1, 2, and 3 reveals some
important feature regarding their structure formations. In
compound 1, Hbpdc2 is partly deprotonated and
coordinated as a monodentate ligand, in compound 2,
bpdc22 is fully deprotonated and coordinated as bis-
monodentate mode, while in compound 3 the bpdc22 is
in monodentate–bidentate mode. Therefore, compound 1
is a monomer, compound 2 is a one-dimensional chain,
and compound 3 is a rhombic species.
Fig. 3. ORTEP view of [Cu(bpdc)(phen)(H2O)]n (2).
Table 3
Selected bond lengths and angles for compound 2
Cu1–O1
Cu1–O5
Cu1–N2
1.931(4)
1.963(3)
2.025(5)
Cu1–O4#
Cu1–N1
2.267(4)
2.015(4)
In summary, the syntheses and structures of two
compounds, [Cu(Hbpdc)2(phen)] (1) and [Cu(bpdc)
(phen)(H2O)]n (2), have been accomplished. The
framework diversity associated with compounds 1 and
O1–Cu1–O4#
O1–Cu1–N1
O5–Cu1–O4#
O5–Cu1–N2
100.3(2)
O1–Cu1–O5
O1–Cu1–N2
O5–Cu1–N1
N1–Cu1–O4#
95.1(2)
166.0(2)
166.8(2)
100.8(2)
89.9(2)
90.4(2)
91.7(2)
2
shows monomer and one-dimensional chain.
The exploration of the nature of framework diversity
will be benefit for the design of new functional
compounds.
N1–Cu1–N2
81.0(2)
N2–Cu1–O4#
91.9(2)
Symmetry code: #, 1 2 2 þ x, 21/2 þ y, z.
Fig. 4. One-dimensional network of [Cu(bpdc)(phen)(H2O)]n (2).

104
S.-Y. Zhang et al. / Journal of Molecular Structure 699 (2004) 101–104
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Crystallographic data (excluding structure factors) for
the structural analysis have been deposited with the
Cambridge Crystallographic Data Center as supplementary
publication No. 235941 and 235942 for compounds 1 and 2,
respectively. Copies of the data can be obtained free of
charge via www.ccdc.ac.uk/conts/retrieving.html (or from
The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK, fax: þ44-1223-336-033. E-mail: deposit@ccdc.cam.
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