Rigidity versus Flexibility of Ligands in the Assembly of Entangled Coordination Polymers Based on Bi- and Tetra Carboxylates and N-Donor Ligands

Article abstract of DOI:10.1021/acs.cgd.5b00642

Seven Zn(II) coordination polymers including [Zn(pbda)(p-bimb)]·H₂O (1), [Zn(pbda)(bpa)_0.5] (2), [Zn(pbda)(bpp)] (3), [Zn(Hpbda)₂(bibm)₂] (4), [Zn(pbta)_0.5(m-bimb)]·H₂O (5), [Zn(pbta)_0.5(bpp)(H₂O)] (6), and [Zn(H₂pbta)(bibm)]·H₂O (7) (H₂pbda = 4,4′-{[1,4-phenylenebis(methylene)]bis(oxy)}dibenzoic acid; p-bimb = 1,4-bis(1H-imidazol-l-yl)methyl)benzene; bpa = 1,2-bis(4-pyridyl)ethane; bpp = 1,3-bis(4-pyridyl)-propane; bibm = 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl; m-bimb = 1,3-bis(1H-imidazol-l-yl)methyl)-benzene; H₄pbta = 5,5′-phenylenebis(methylene)-1,1′-3,3′-(benzene-tetracarboxylic acid) were prepared under solvothermal conditions and structurally characterized. Compound 1 shows a three-dimensional (3D) channel-like architecture constructed by helical chain subunits. Compound 2 shows a rare 2D + 2D + 2D → 2D network with both polyrotaxane and polycatenane features. 3 holds a 2D layer structure constituted of metal-sharing right- and left-handed helical chains. Compound 4 presents a one-dimensional (1D) chain which is decorated by long side arms around the chain. Compound 5 possesses a 2D wave-like layer formed by [Zn₂(m-bimb)]_n chains by linear pbta ligands. Compound 6 displays a 3D framework that is stabilized by hydrogen bonding interactions between the coordinated H₂O molecules and the neighboring carboxylate oxygen atoms. Compound 7 possesses a 1D + 1D → 2D polycatenation motif. The results demonstrated that the rigidity versus flexibility of the ligands along with the number of carboxyl groups make an impact on the structural diversities of the entangled coordination polymers. Moreover, compounds 3 and 6 as representative examples possessed high catalytic efficiency for the photodecomposition of methyl blue in water using natural sunlight irradiation. (Figure Presented).

Full text of DOI:10.1021/acs.cgd.5b00642

Article
pubs.acs.org/crystal
Rigidity versus Flexibility of Ligands in the Assembly of Entangled
Coordination Polymers Based on Bi- and Tetra Carboxylates and
N‑Donor Ligands
Shu-Long Wang,†,‡,# Fei-Long Hu,†,§,# Ju-Ying Zhou,‡ Yan Zhou,‡ Qin Huang,*,‡ and Jian-Ping Lang*,†
†College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
‡Guangxi Key Laboratory of Chemistry and Engineering of Forest Products, Guangxi University for Nationalities, Nanning, 530006,
P. R. China
§Guangxi Colleges and Universities Program of Innovative Research Team and Outstanding Talent, College of Chemistry and
Material, Yulin Normal University, Yulin, 537000, P. R. China
S
* Supporting Information
ABSTRACT: Seven Zn(II) coordination polymers including [Zn(pbda)-
(p-bimb)]·H2O (1), [Zn(pbda)(bpa)0.5] (2), [Zn(pbda)(bpp)] (3),
[Zn(Hpbda)2(bibm)2] (4), [Zn(pbta)0.5(m-bimb)]·H2O (5), [Zn(pbta)0.5-
(bpp)(H2O)] (6), and [Zn(H2pbta)(bibm)]·H2O (7) (H2pbda = 4,4′-
{[1,4-phenylenebis(methylene)]bis(oxy)}dibenzoic acid; p-bimb = 1,4-
bis(1H-imidazol-l-yl)methyl)benzene; bpa = 1,2-bis(4-pyridyl)ethane; bpp
= 1,3-bis(4-pyridyl)-propane; bibm = 4,4′-di(1H-imidazol-1-yl)-1,1′-
biphenyl; m-bimb = 1,3-bis(1H-imidazol-l-yl)methyl)-benzene; H4pbta =
5,5′-phenylenebis(methylene)-1,1′-3,3′-(benzene-tetracarboxylic acid)
were prepared under solvothermal conditions and structurally charac-
terized. Compound 1 shows a three-dimensional (3D) channel-like
architecture constructed by helical chain subunits. Compound 2 shows a
rare 2D + 2D + 2D → 2D network with both polyrotaxane and
polycatenane features. 3 holds a 2D layer structure constituted of metal-
sharing right- and left-handed helical chains. Compound 4 presents a one-
dimensional (1D) chain which is decorated by long side arms around the
chain. Compound 5 possesses a 2D wave-like layer formed by [Zn2(m-
bimb)]n chains by linear pbta ligands. Compound 6 displays a 3D
framework that is stabilized by hydrogen bonding interactions between the
coordinated H2O molecules and the neighboring carboxylate oxygen atoms.
Compound 7 possesses a 1D + 1D → 2D polycatenation motif. The results demonstrated that the rigidity versus flexibility of the
ligands along with the number of carboxyl groups make an impact on the structural diversities of the entangled coordination
polymers. Moreover, compounds 3 and 6 as representative examples possessed high catalytic efficiency for the
photodecomposition of methyl blue in water using natural sunlight irradiation.
Polycarboxylate ligands may have many kinds of coordina-
tion modes and have been extensively adopted in the
preparation of CPs. In the family of polycarboxylate ligands,
biphenyl-based bi- and tetracarboxylates are of special interest
because the two phenyl rings can freely rotate to generate
different conformations.32 If the two phenyl groups of the
ligand are separated by other groups such as −O−, −CH2−,
and −O−CH2−, the phenyl groups may freely rotate around
these groups according to the coordination requirement of the
metal ions in the assembly process. Moreover, the carboxylate
arms can readily change their conformations to satisfy the
INTRODUCTION
■
Design and synthesis of novel entangled networks have
attracted great attention due to their interesting topological
architectures and potential applications.1−9 It is still difficult to
identify the main factors directing the final structures10−12
because many factors such as auxiliary ligands,13,14 metal ions,15
reaction temperatures,16 pH values,17 etc. may affect the
diversities of the resulting assemblies.18−21 It is well-known that
the design and selection of suitable ligands are quite critical in
the formation of the coordination frameworks. The rigidity and
flexibility of the ligand employed should be specially
considered.22−31 Therefore, the appropriate organic ligands
along with the careful control of reaction conditions are key
factors for achieving entangled coordination polymers (CPs).
Received: May 18, 2015
Revised: June 20, 2015
© XXXX American Chemical Society
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Scheme 1. Structures of H2pbda and H4pbta and Auxiliary N-Donor Ligands Used in This Work
Figure 1. (a) View of the coordination environment of the Zn(II) center in 1. (b) View of the helical channels in the 3D architecture of 1. (c) View
of a section of the 1D meso-helical chain. (d) The simplified representation of the 2-fold interpenetration in 1.
coordination requirements of the metal ions through their
“breathing” behavior in the solid state.33 On the contrary, if two
or more carboxyl groups on the same phenyl ring coordinate to
one metal ion, the phenyl ring is fixed and turned rigid to some
extent. Therefore, the tetracarboxylate ligands separated by
−O−CH2−phenyl−CH2−O− groups are expected to show
both flexible and rigid properties in the assembly of CPs.
On the other hand, the N-donor ligands also have a crucial
influence in the assembly process.34−45 Up to now, a large
number of CPs containing flexible or rigid N-donor ligands
have been reported.46−50 The rigid one possesses a certain
rigidity and stability, which can reduce the uncertainty in the
assembly process. However, the flexible N-donor ligands may
take different coordination modes, which increase the complex-
ity of the resulting coordination polymers.
In this article, we designed and synthesized two poly-
(carboxylic acid) ligands, 4,4′-{[1,4-phenylenebis(methylene)]-
bis(oxy)}dibenzoic acid (H2pbda)51 and 5,5′-phenylenebis-
(methylene)-1,1′-3,3′-(benzene-tetracarboxylic acid)52
(H4pbta) (Scheme 1). Their reactions with ZnSO4 in the
presence of five auxiliary N-donor ligands (Scheme 1) (1,4-
bis(1H-imidazol-l-yl)methyl)benzene (p-bimb); 1,2-bis(4-
pyridyl)ethane (bpa); 1,3-bis(4-pyridyl)-propane (bpp); 4,4′-
di(1H-imidazol-1-yl)-1,1′-biphenyl (bibm); 1,3-bis(1H-imida-
zol-l-yl)methyl)-benzene (m-bimb)) under solvothermal con-
ditions produced seven coordination polymers: [Zn(pbda)(p-
bimb)]·H2O (1), [Zn(pbda)(bpa)0.5] (2), [Zn(pbda)(bpp)]
(3), [Zn(Hpbda)2(bibm)2] (4), [Zn(pbta)0.5(m-bimb)]·H2O
(5), [Zn(pbta)0.5(bpp)(H2O)] (6) and [Zn(H2pbta)(bibm)]·
H2O (7). All these compounds were characterized and
structurally determined. The effects of rigidity versus flexibility
of ligands employed on the structural diversities of these
compounds are discussed. In addition, compounds 3 and 6
were selected as representative examples and presented good
photocatalytic performances in decomposing methyl blue (MB)
in water under sunlight.
RESULTS AND DISCUSSION
■
Synthesis and Characterization. The reactions of ZnSO4·
7H2O with H2pbda and p-bimb (molar ratio = 2:1:1) in H2O/
DMF (v/v = 6:4) at 145 °C for 2 days under solvothermal
conditions gave colorless crystals of 1 in 52% yield. Other
similar reactions of ZnSO4·7H2O with H2pbda and L (molar
ratio = 2:1:1) or ZnSO4·7H2O with H4pbta and L afforded
colorless crystals of 2 (60% yield) for L = bpa, 3 (40% yield)
for L = bpp, and 4 (45% yield) for L = bibm, block crystals of 5
(50% yield) for L = m-bimb, block crystals of 6 (60% yield) for
L = bpp, and sheet crystals of 7 (48% yield) for L = bibm,
respectively. In addition, analogous reaction of ZnSO4·7H2O
B
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Figure 2. (a) View of the coordination environment of the Zn(II) center in 2. (b) View of the single 2D sheet in 2. (c) View of three
interpenetrating sheets in 2. (d) Schematic view of the parallel 2D → 2D 3-fold interpenetration in 2.
Figure 3. (a) View of the coordination environment of the Zn(II) center in 3. (b) View of the single 2D layer in 3. (c) View of the 2D layer
constituted by helical chains in 3. (d) Two identical layers interpenetrated into each other forming the 2D + 2D → 2D in 3.
with H4pbta and bpa afforded colorless crystals of a known
compound [Zn2(pbta)(bpa)2]·4H2O.14 Compounds 1−7 are
air-stable and do not dissolve in water and other organic
solvents. The observed C, H, and N contents of 1−7 matched
well with their theoretical ones. The experimental powder X-ray
diffraction (PXRD) patterns of 1−7, measured at room
temperature, were consistent with the simulated ones,
suggesting the good phase purity of these compounds (Figures
S1 and S2). The IR spectra of 1−7 exhibited asymmetry and
symmetric stretching vibrations of the coordinated carboxylate
groups at 1521−1634 cm−1 and 1321−1489 cm−1.53−58 The
νas(COOH) of the uncoordinated carboxyl group in 7 appeared
at 1706 cm−1. The ν(O−H) of the coordinated and lattice
water molecules in 1 and 5−7 were located in the range of 3100
and 3500 cm−1.54 The bands of 1540−1622 cm−1 in 1, 4, 5, and
7 referred to the CN stretching vibration of imidazole
rings.55,58,59
Crystal Structure of [Zn(pbda)(p-bimb)]·H2O (1).
Compound 1 belongs to the P21/c space group, and its
asymmetric unit consists of one [Zn(pbda)(p-bimb)] unit and
one solvent water molecule. Each Zn(II) atom is tetrahedrally
coordinated by two O atoms from two pbda ligands and two N
atoms from two p-bimb ligands (Figure 1a). In 1, each p-bimb
links two Zn(II) centers to afford a [Zn2(p-bimb)] unit that
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Figure 4. (a) View of the coordination environment of the Zn(II) center in 4. (b) View of the [Zn2(pbda)2] unit. (c) Schematic description of the
π···π stacking interactions of 4. (d) Viewing of the 2D supramolecular layer formed by π···π stacking interactions between the benzene of bibm
ligands in 4.
propagates into a 1D chain along the c axis. Two adjacent
chains are interconnected by pbda ligands into a railway-like
motif. Half of one pbda ligand links the [Zn2(p-bimb)]n chains
along the parallel direction, while the other half hooks the two
adjacent [Zn2(p-bimb)]n chains in a up-and-down way. A three-
dimensional (3D) framework with a one-dimensional (1D)
helical channels along the a axis is thus observed in 1 (Figure
1b,c). Such a structure could be simplified as a 3D + 3D → 3D
interpenetrated net (Figure 1d). The C−H···π and hydrogen
bonding interactions play significant roles in the stabilization of
the 3D framework of 1 with a C(35)−H(35)···Cg distance of
2.93(7) Å (Cg is the center of benzene ring constituted by
C(2) to C(7)). In 1, each pbda displays a linear linker in which
two benzoates slightly rotate around the −O− or −O−CH2−
units, while the two imidazole rings of p-bimb do much around
these units to satisfy the requirement of the Zn(II)
coordination geometry.
Crystal Structure of [Zn(pbda)(bpp)] (3). Compound 3
belongs to the P1 space group, and its asymmetric unit consists
̅
of one discrete [Zn(pbda)(bpp)] unit. Each Zn(II) center is
tetrahedrally coordinated by two O atoms from two pbda
molecules and two N atoms from two bpp molecules (Figure
3a). Three phenyl rings of each pbda are noncoplanar and
rotate away with dihedral angles of 63.4(5)° and 61.4(6)°
between the central phenyl and the adjacent ones. Each pbda or
bpp ligand links two Zn(II) centers, while each Zn(II) binds
four pbda or bpp ligands to afford a 2D layer (Figure 3b).
Analysis of the packing of 3 reveals that the layer is assembled
through the rhombus ring with side lengths of 11.616 Å ×
18.424 Å. Pbda and bpp ligands alternatively bridge Zn(II)
centers to form left- and right-handed helical chains extending
along the c axes, where the right- and left-handed helices are
formed equally with the pitch of 15.685 Å. As shown in Figure
3c, adjacent helical chains are joined together by Zn(II)-
sharing, thereby forming an achiral 2D layer. Two identical
layers interpenetrate each other into a 2D + 2D → 2D fashion
(Figure 3d). Neighboring layers are further stacked into a 3D
structure through the edge-to-face interactions and strong
hydrogen bonds.
Crystal Structure of [Zn(pbda)(bpa)0.5] (2). Compound
2 belongs to the P1 space group, and its asymmetric unit has
̅
one [Zn(pbda)(bpa)0.5] unit. Each Zn(II) center adopts a
distorted square pyramidal geometry, coordinated by four O
atoms from four H2pbda ligands and one N atom from bpa
(Figure 2a). A paddled-wheel [Zn2(COO)4] subunit with four
carboxyl groups of pbda ligand chelating two Zn(II) centers is
formed with a short Zn···Zn distance of 2.909 Å. Two pbda
ligands link two [Zn2(COO)4] subunits to yield an elliptic
[Zn4(pbda)2] unit. Such units expand along the (−101)
direction through bpa ligands to generate a two-dimensional
(2D) network60−62 (Figure 2b). Three identical 2D networks
interpenetrate into each other in a 2D + 2D + 2D → 2D
parallel fashion, thereby forming an uncommon 2D polyrotax-
ane layer (Figure 2c). In this way, bpa acts as a rod to pass
through the loop of the [Zn4(pbda)2] unit and vice versa
(Figure 2d). Adjacent layers are stacked together through C−
H···π and lone pair···π interactions (O(6)···Ch = 3.57(9) Å,
C(8)−H(8)···Ci = 2.82(2) Å; Ch is center of phenyl group
constituted by C(16) to C(21); Ci is the center of ring defined
by C(2) to C(7)). To our knowledge, such a 2D entanglement
sheet that exhibits both polyrotaxane and polycatenane features
is quite rare.21,63−65
Crystal Structure of [Zn(Hpbda)2(bibm)2] (4). Com-
pound 4 conforms to the P1 space group, and its asymmetric
̅
unit has one [Zn(Hpbda)2(bibm)2] unit. The Zn(II) center is
octahedrally coordinated by two N atoms from two bibm
ligands and four carboxyl O atoms from four pbda ligands
(Figure 4a). One carboxyl group of the pbda ligand in 4 is
protonated in order to balance the negative charge. The bond
lengths of Zn−O vary in the range of 2.216(3)−2.239(4) Å,
and the Zn−N bond length of 2.202(4) Å is normal according
to the literature.66 Two Zn(II) centers are joined by two
Hpbda− ligands to form a [Zn2(Hpbda)2] subunit, which
propagates along the c axis into a 1D chain (Figure 4b). The
bibm ligands decorate the chain on both left and right sides
with one of two iminazole groups being intact. The neighboring
chains are connected by π···π stacking interactions with a
distance of 3.736 Å between two aromatic rings (Figure 4c,d).
Because of the absence of the flexibility, the rigid bibm cannot
rotate its uncoordinated iminazole group to meet the Zn
coordination.
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Figure 5. (a) View of the coordination environment of the Zn(II) center in 5. (b) View of a portion of the 1D helical [Zn(m-bimb)]n chain (c)
Schematic representation of a sql net of 5. (d) View of the 1D helical channels in 5.
Figure 6. (a) View of the coordination environment of the Zn(II) center in 6. (b) View of the 1D + 1D → 3D polycatenation in 6. (c) Schematic
view of the interpenetrating nets of 6. (d) View of the 3D interpenetrating structure of 6.
Crystal Structure of [Zn(pbta)0.5(m-bimb)]·H2O (5).
Compound 5 conforms to the P21/c space group, and one
[Zn(pbta)0.5(m-bimb)] unit and one water solvent molecule
are contained in its asymmetric unit. Each Zn(II) center is
tetrahedrally coordinated by two N atoms from m-bimb and
two O atoms from pbta ligands (Figure 5a). The average bond
lengths of Zn−O (1.951(3) Å) and Zn−N (2.029(4) Å) are
comparable to the corresponding value in 1. Each m-bimb in 5
bridges two Zn(II) centers to generate a [Zn2(m-bimb)] unit,
which propagates along the c axis to yield a [Zn2(m-bimb)]n
chain (Figure 5b). The [Zn2(m-bimb)]n chains are inter-
connected by linear pbta ligands to form a sql layer (Figure 5c).
Compared with the flexibility of m-bimb, the three phenyl rings
in each pbta are nearly coplanar with the dihedral angles of
10.54°, indicating the approximate rigidity of pbta. The 1D
helical channels are formed by cross-linked pbta ligands along
the b axis (Figure 5d). The 2D layers are further developed into
a 3D structure by hydrogen bonds and π···π stacking
interactions with the center-to-center distance of 3.978 Å
(Cj···Cj′ = 3.978 Å, Cj is the benzene ring constituted by C16
to C21, while Cj′ is the center of benzene ring constituted by
C24, C25, C26, and their equivalents).
Crystal Structure of [Zn(pbta)0.5(bpp)(H2O)] (6). Com-
pound 6 belongs to the P1 space group, and its asymmetric unit
̅
has one [Zn(pbta)0.5(bpp)(H2O)] unit. Each Zn(II) center
adopts a trigonal bipyramidal geometry, coordinated by two N
atoms from bpp and three O atoms from pbta and water
molecule, respectively. The average bond length of Zn−O
(2.063(3) Å) is longer than that found in [Zn(bdc)(4,4′-
bipy)(H2O)]·1.5H2O (1.952(2) Å, bdc = 1,3-benzenedicarbox-
ylates, 4,4′-bipy = 4,4′- bipyridine),67 while the mean Zn−
O(H2O) and Zn−N (2.173(3) vs 2.093(3) Å) bond lengths are
shorter than those observed in [Zn(bdc)(4,4′-bipy)(H2O)]·
1.5H2O (2.167(2) Å vs 2.188(2) Å). As shown in Figure 6b, a
zigzag chain along the c axis is formed through the linkage of
bpp and Zn centers. Two adjacent chains are joined by two
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Figure 7. (a) View of the coordination environment of the Zn(II) center in 7. (b) View of one section of the 1D rectangle-shaped nanotube of 7. (c)
View of the 1D + 1D → 2D polycatenation in 7. (d) Schematic presentation of the 3-fold interpenetration in 7.
carboxyl groups from each pbta to give a railway-like double
chain. Such chains propagate along the ac plane to form a 2D
layer structure by the connection of the remaining carboxyl
groups of the pbta ligands with Zn centers. The adjacent layers
are further stacked into a 3D framework by C−H···π (C−H···
Cg = 2.958 Å, C−H···Cg = 154.4°, Cg is the center of the
pyridine ring constituted by N2, C1 to C5) and hydrogen
bonding (O6−H−O2, O6−H−O4) interactions. Each pbta
displays a “Z-shaped’’ motif with a dihedral angle of 82.9(8)°
between the central and terminal phenyl rings. Unlike 5, in
which each pbta shows a linear pattern, the pbta ligand in 6
encapsulates the space decorated by the [Znn(bpp)m] units and
function as pillars to support the [Znn(bpp)m] units (Figure
6c,d). The two pyridine rings of the bpp ligands in 3 and 6 are
arranged in a nearly parallel fashion (82.98° vs. 89.6°).
However, 3 and 6 present completely different networks due
to the different carboxylate ligands used. The dihedral angle of
two pyridyl rings located at the axial direction is 103°, implying
that two pyridyl rings bend seriously along the −CH2−CH2−
CH2− group. This may ascribed to the requirement of the
arched conformation of pbta. This structural information
suggests that pbta and bpp in 6 serve as flexible ligands. It
seems that bpp is more flexible than bpa due to the presence of
one more −CH− group.
the Zn centers and the ligands are regarded as nodes and rods,
respectively (Figure 7c,d). In this structure, each pbta works as
a flexible ligand but bibm as a rigid one.
As described above, compounds 1−7 possesses quite
different polydimensional architectures. These structural
diversities are probably due to the rigidity versus flexibility of
the ligands along with the number of carboxyl groups in
carboxylate ligands. In 1−4, the different conformations of the
pbda ligand were observed though the same pbda was used.
The structural diversities of 1−4 may also be ascribed to the
rigidity or flexibility of the auxiliary N-donor ligands.
Compound 2 displays a 2D + 2D + 2D → 2D interpenetrating
network due to the flexible pbda. Pbda shows a flexible feature
in 3 and 4, while it exhibits a rigid character in 1. When the
number of carboxylate groups was increased to four, the
employment of such a ligand (H4pbta) led to the formation of
different structures of 5−7. As expected, it is hard for pbta to
rotate its bulk groups freely to form the rods like motifs
observed in 5. Two carboxyl groups on one phenyl ring of pbta
binded at Zn(II) simultaneously will restrict the movement of
the ligand. Both phenyl rings (bonded by carboxyl groups) of
pbta in 5 are nearly in a plane. Although 7 displays a rod-loop
framework, each H4pbta has its two carboxyl groups
uncoordinated, which makes it act as H2pbda in 1−4. In
addition, [Zn2(pbta)(bpa)2]·4H2O33 also shows that pbta binds
the Zn ions by using two of its carboxyl groups, and the three
benzene rings are nearly in a plane. 2 shows a similar motif to
that of 7 with two adjacent rods penetrating into the loops
formed by Zn2(pbda)2 units. However, 2 shows a 2D + 2D +
2D → 2D polycatenation network, while 7 displays a 1D + 1D
→ 2D network. Such a structural difference is probably due to
the different positions of the carboxyl groups attached at the
phenyl ring (para-position in 2, and meta-position in 7). The
flexibility and the rigidity of the ligands interact with each other
and which one dictates the final topologic structures of the
resulting CPs highly depends on the lengths and geometries of
the ligands employed.
Crystal Structure of [Zn(H2pbta)(bibm)]·H2O (7).
Compound 7 belongs to the P1 space group, and its
̅
asymmetric unit contains one [Zn(H2pbta)(bibm)] unit and
one water solvent molecule. The Zn(II) atom is tetrahedrally
coordinated to two N atoms from bibm ligands and two O
atoms from monodentate carboxylate groups of pbta (Figure
7a). Unlike the structures of 5 and 6, two deprotonated
carboxyl groups of H2pbta2− in 7 bind to two Zn(II) centers,
while the other two keep protonated. In this way, each Zn(II) is
connected to two H2pbta2− ligands to form a [Zn2(H2pbta2−)2]
rectangle unit with a dimension of 12.3 Å × 10.9 Å. These units
are pillared by bibm ligands to afford a 1D rectangle-shaped
nanotube68 (Figure 7b). Adjacent nanotubes are packed
together through the hydrogen bonds and unconventional
interactions (C−H···π, C−H···O). The whole architecture can
be simplified as a 1D + 1D → 2D polycatenation motif when
Thermal Property. To characterize the thermal stability of
these compounds, thermogravimetric analyses (TGA) of 1−7
(Figures S3 and S4) were carried out using a similar method.10
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Figure 8. (a) Absorption spectra of the solutions of MB in the presence of 3 under sunlight irradiation. (b) Absorption spectra of the solutions of
MB in the presence of 6 under sunlight irradiation.
The TGA analysis revealed that these compounds were quite
stable up to 200 or 300 °C. Compound 1 lost 2.61% (calculated
2.59%) of its weight in the first stage from 25 to 200 °C, which
can be assigned to the release of one lattice water molecule.
After that, the structure began to collapse above 330 °C.
Compound 2 was stable up to 370 °C and then decomposed
into metal oxide at higher temperature. Compounds 3 and 4
showed high thermal stability below 300 °C. When the
temperature was elevated, the products gradually lost pbda and
p-bimb (1), bpa (2), bpp (3), or bibm (4). Compound 5 lost
its lattice water molecule below 300 °C with the weight loss of
2.52% (calculated 3.25%). When the temperature increased, it
began to decompose gradually. The weight loss between 30 and
150 °C of 6 can be assigned to dissociate of the coordinated
water molecules (observed 2.65%; calculated 3.48%). For 7,
there was no weight loss observed in the range of 30−200 °C.
The lattice water molecule may evaporate when samples are
exposed to the air, and it started to decompose at 360 °C.
Photoluminescent Property. Coordination polymers with
d10 metal centers69−72 have been widely investigated for their
photoluminescent properties and their potential applications as
fluorescent materials.73−75 In the present work, the photo-
luminescent properties of 1−7 together with the free H2pbda
and H4pbta ligands were studied in the solid state at room
temperature. The emission spectra of these compounds and the
two carboxylate ligands were presented in Figures S5−S6. The
free H2pbda and H4pbta ligands display intense emission bands
with maxima about 340 and 358 nm (λex = 280 nm),
respectively, which may be attributed to the π* → π
transitions.76−78 For 1, the emission peak at 330 nm was
found (λex = 285 nm), which was similar to that of H2pbda.
Similarly, 6 and 7 showed the emission bands at about 358 and
356 nm, respectively, which are analogous to the H4pbta ligand.
The emissions of compounds 1−7 are tentatively ascribed to be
a ligand-to-ligand charge transfer (LLCT) nature.79−83 The
emission bands at 440 and 354 nm (λex = 290 nm) were
observed for compounds 2 and 4, which were highly red-shifted
by 100 nm (2) and 14 nm (4) compared with the free H2pbda.
Compound 3 showed an intense emission band at ca. 309 nm
(λex = 290 nm), which was blue-shifted by 31 nm compared
with the free H2pbda. Compound 5 exhibited an intense
emission band at 336 nm (λex = 280 nm), which was blue-
shifted by 22 nm compared with free H4pbta (Figure 6). These
emission origins may be assigned as either the ligand-to-metal
charge transfer (LMCT) or LLCT transitions.84−86 The
different emission bands of 1−7 may be also ascribed to the
rigidity versus flexibility of the ligands and their different
architectures described above.87
Optical and Photocatalytic Properties. In order to
investigate the optical properties of these compounds,
compounds 3 and 6 were taken as representative examples.
Following a similar method,10 the band gap energies (Eonset) of
3 and 6 were estimated to be 3.4 and 3.6 eV, respectively
(Figure S7). Thus, 3 and 6 may be regarded as semiconducting
materials and employed as potential photocatalysts upon
exposure to sunlight.88−90
The photocatalytic activities of 3 and 6 were assessed by
decomposing MB in water under natural sunlight irradiation. As
we know, the examples of the CPs exhibiting obvious
photocatalytic properties for degrading MB under sunlight
irradiation are very limited.91 Herein, we examined the
photocatalytic activities of 3 and 6 toward the decomposition
of MB in water using sunlight irradiation. The typical
procedures for the preparation of the MB solution and the
catalyst were carried out according to the literature.10 As shown
in Figure 8, the absorption peaks of MB decreased obviously
along with the increase of the reaction time. The photocatalytic
activity increased from 25% (without any catalyst, Figure S8) to
87% for 3 and 83% for 6 after 180 min. Obviously, the
degradation efficiency of 3 under sunlight irradiation was
slightly higher than 6, which may be attributed to the smaller
energy gap of 3.92−97 Their efficiencies were somewhat higher
than those obtained by coordination polymers under UV light
irradiation reported recently.98,99 For example, compounds
[Co(L1)(1,3-BDC)(H2O)2] (L1 = N,N′-bis(3-pyridyl)-
malonaminde) and [Co(L2)(L3)2] (H4L2 = tetrakis[4-(carbox-
yphenyl)-oxamethyl]methane acid, L3 = 4-tolyl-2,2′:6′,2″-
terpyridine) showed 81% and 46% degradation of MB after
130 and 210 min of UV light irradiation, respectively. The
results showed that 3 and 6 possessed relatively high catalytic
efficiencies for the degradation of MB in aqueous solution
under sunlight. The PXRD patterns of the recycled samples (3
and 6) showed no obvious difference from those of as-
synthesized 3 and 6 (Figure S9), indicating their good stability
and recyclability in such photocatalytic degradation of organic
dyes in water using natural sunlight irradiation.
CONCLUSIONS
■
In conclusion, seven entangled networks of 1−7 were isolated
from solvothermal reactions of ZnSO4·7H2O with two
poly(carboxylic acid) ligands (H2pbda and H4pbta) and five
auxiliary N-donor ligands (p-bimb, bpa, bpp, m-bimb, and
G
DOI: 10.1021/acs.cgd.5b00642
Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design
Article
Table 1. Crystal Data and Structure Refinement Parameters for 1−7
1
2
3
4
5
6
7
empirical formula
formula weight
crystal system
space group
a (Å)
C36H32N4O7Zn
698.01
C28H22NO6Zn
533.84
C35H30N2O6Zn
640.00
C80H62N8O12Zn
1392.75
C26H23N4O6Zn
552.84
C25H23N2O6Zn
512.82
C42H32N4O11Zn
834.09
monoclinic
P21/c
triclinic
triclinic
triclinic
monoclinic
P21/c
triclinic
triclinic
P1
̅
P1
̅
P1
̅
P1
̅
P1
̅
8.3471(17)
20.085(4)
19.236(4)
9.3717(19)
11.209(2)
12.227(2)
109.67(3)
96.74(3)
96.16(3)
1186.2(4)
2
9.1199(18)
11.616(2)
15.685(3)
96.54(3)
100.43(3)
106.40(3)
1543.5(6))
2
9.5318(19)
12.490(3)
14.214(3)
76.45(3)
86.68(3)
83.09(3)
1632.4(6)
1
8.7037(17)
16.355(3)
18.856(5)
9.8901(8)
11.001(7)
11.9223(11)
82.982(6)
77.657(7)
65.772(7)
1154.71(16)
2
9.8893(9)
12.2772(11)
15.8563(16)
75.014(8)
76.456(8)
82.337(7)
1802.5(3)
2
b (Å)
c (Å)
α (deg)
β (deg)
91.51(3)
115.71(2)
γ (deg)
V (Å3)
3223.8(11)
4
2418.4(9)
4
Z
T/K
Dcalcd (g cm−3
293(2)
1.434
296(2)
1.495
296(2)
1.377
293(2)
1.417
293(2)
1.513
293(2)
293(2)
)
1.475
1.533
λ(Mo Kα) (Å)
0.71073
0.819
0.71073
1.081
0.71073
0.844
0.71073
0.451
0.71073
1.066
0.71073
1.108
0.71073
0.754
μ (mm−1
)
F(000)
1440
550.0
664
724
1132
530
856
a
R1
0.0781
0.2025
0.0415
0.0810
0.0953
0.2445
1.113
0.0881
0.1749
1.226
0.0325
0.0747
b
wR2
0.0911
0.1424
0.0796
0.1769
c
GOF
0.949
1.085
1.083
1.058
0.988
a
b
c
2
R1 = Σ||F0| − |Fc||/Σ|F0|. wR2 = {Σw(F02 − Fc2)2/Σw(F0 )2}1/2. GOF = {Σw((F02 − Fc2)2)/(n − p)}1/2, where n = number of reflections and p =
total numbers of parameters refined.
was stirred under nitrogen at 80 °C for 12 h and then concentrated in
vacuo. A 3 M HCl aqueous solution was added slowly into the solution
at room temperature to afford a white solid, which was collected,
washed with water, and dried in vacuo to give 1.38 g (85%) of H2pbda.
IR (KBr, cm−1): 3075 (w), 3012 (w), 2953 (m), 2892 (w), 1673 (vs),
1603 (s), 1502 (s), 1427 (s), 1372 (s), 1253 (s), 1162 (s), 1102 (m),
1032 (m), 1012 (w), 953 (w), 842 (s), 773 (s), 643 (s). H NMR
(DMSO-d6, δ): 5.201 (4H, s), 7.114 (4H, d), 7.496 (4H, d), 7.907
(4H, d) (Figure S10).
bibm). These compounds showed intriguing 1D, 2D, and 3D
topological frameworks, which made them versatile candidates
for the assembly of CPs with aesthetic structures. Their
structural diversities demonstrate that the rigidity−flexibility
relationship of the ligands along with the number of carboxyl
groups exert significant impact on the self-assembly of
coordination frameworks. The long flexible ligand which has
only two carboxyl groups (H2pbda) can easily form rod-like
structures by bending its −O−CH2− groups (1, 2, and 7).
However, H4pbta with two or more carboxyl groups on one
phenyl ring coordinated to the metal can restrict the movement
of some groups, which makes the ligand a rigid one (5). Under
the sunlight irradiation, compounds 3 and 6 as representative
examples exhibited high catalytic activity toward the photo-
degradation of MB in water. Both compounds show good
stability and recyclability. These results further reveal that these
compounds may become potential catalysts in photodecompos-
ing some dye molecules in industrial wastewaters under visible
light irradiation.
1
[Zn(pbda)(p-bimb)]·H2O (1). A mixture containing ZnSO4·7H2O
(29 mg, 0.1 mmol), H2pbda (19 mg, 0.05 mmol), p-bimb (12 mg, 0.05
mmol), and 2 mL of H2O and DMF (v/v = 6:4) was loaded in a thick
Pyrex tube. The tube was then sealed and heated to 145 °C for 2 days.
After that, it was cooled to ambient temperature at a rate of 5 °C/h to
afford colorless crystals of 1 in 51% yield (based on ZnSO4·7H2O).
Anal. Calcd for C36H32N4O7Zn: C, 61.94; H, 4.58; N, 8.02%. Found:
C, 62.02; H, 4.65; N, 7.91%. IR (KBr disk, cm−1): 3436 (w), 1602
(m), 1248 (m), 1101 (w), 1061 (w), 851 (w), 782 (m), 654 (s).
[Zn(pbda)(bpa)0.5] (2). Compound 2 was obtained as colorless
block crystals by using a similar method to that described for 1, except
that p-bimb was replaced by bpa (9.4 mg, 0.05 mmol). Yield: 60%
(based on ZnSO4·7H2O). Anal. Calcd for C28H22NO6Zn: C, 62.99; H,
4.12; N, 2.62%. Found: C, 62.92; H, 4.23; N, 2.50%. IR (KBr disk,
cm−1): 1634 (s), 1602 (m), 1540 (m), 1394 (s), 1251 (m), 1174 (m),
1105 (w), 853 (w), 782 (m), 648 (s).
[Zn(pbda)(bpp)] (3). Compound 3 was prepared in an route
analogous to that used for the isolation of 1, with ZnSO4·7H2O (29
mg, 0.1 mmol), H2pbda (19 mg, 0.05 mmol), bpp (10 mg, 0.05
mmol), and 2 mL of H2O and DMF (v/v = 6:4). Yield: 40% (based on
ZnSO4·7H2O). Anal. Calcd for C35H30N2O6Zn: C, 65.68; H, 4.69; N,
4.38%. Found: C, 65.60; H, 4.72; N, 4.45%. IR (KBr disk, cm−1): 1601
(m), 1540 (m), 1396 (w), 1251 (m), 1101 (w), 846 (m), 782 (m),
659 (s).
EXPERIMENTAL SECTION
■
General Procedures. The H4pbta ligand was prepared according
to a literature method.46−50 The instruments involved in this article
were the same as those used in our previous works unless otherwise
noted.10,21,25
Synthesis. H2pbda. H2pbda was prepared according to a modified
literature method.46−50 A mixture of methyl 4-hydroxybenzoate (6.09
g, 40 mmol), α,α′-dibromo-p-xylene (5.28 g, 20 mmol), 18-crown-6
(0.13 g, 0.5 mmol), and K2CO3 (6.08 g, 44 mmol) in acetone (100
mL) was refluxed for 20 h. The mixture was then cooled to ambient
temperature and CH2Cl2 (60 mL) was added. After the resulting
mixture was further stirred for 30 min and filtered, the filtrate was
concentrated to dryness in vacuo, and the residue was dissolved in
CH3OH (200 mL) at 70 °C. H2O (100 mL) was then added and
cooled to room temperature again. The resulting solid was collected,
washed with CH3OH/H2O (v/v = 2:1), and dried at 80 °C for 10h to
obtain 7.56 g (93%) of ester H2pbda as a white solid. To a solution of
ester H2pbda (1.624 g, 4.0 mmol) was added KOH (1.120 g, 20
mmol), methanol (30 mL), and water (30 mL). The resulting mixture
[Zn(Hpbda)2(bibm)2] (4). Compound 4 was prepared in a similar
method to that used for the isolation of 1, except that p-bimb was
replaced by bibm (14 mg, 0.05 mmol). Yield: 45% (based on ZnSO4·
7H2O). Anal. Calcd for C80H62N8O12Zn: C, 68.99; H, 4.45; N, 8.04%.
Found: C, 69.10; H, 4.43; N, 7.92%. IR (KBr disk, cm−1): 1602 (s),
1571 (s), 1456 (s), 1303 (s), 1247 (s), 1170 (m), 1058 (w), 846 (m),
785 (m), 659 (w), 534 (m).
H
DOI: 10.1021/acs.cgd.5b00642
Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design
Article
[Zn(pbta)0.5(m-bimb)]·H2O (5). Compound 5 was prepared as
colorless block crystals by the same synthetic procedure for 1, from
ZnSO4·7H2O (29 mg, 0.1 mmol), H4pbta (23 mg, 0.05 mmol), m-
bimb (12 mg, 0.05 mmol), and 2 mL of H2O and DMF (v/v = 6:4).
Yield: 50% (based on ZnSO4·7H2O). Anal. Calcd for C26H23N4O6Zn:
C, 56.48; H, 4.16; N, 10.13%. Found: C, 56.50; H, 4.19; N, 10.21%. IR
(KBr disk, cm−1): 3444 (m), 1623 (s), 1607 (m), 1576 (m), 1489
(m), 1452 (m), 1371 (s), 1266 (m), 1093 (m), 1036 (s), 853 (w), 776
(s), 658 (m).
“SooChow Scholar” Program of Soochow University. F.-L.H.
also acknowledges the financial support from the Innovative
Research Program for Postgraduates in Universities of Jiangsu
Province (KYZZ-0335) and the Guangxi Natural Science
Foundation (2014GXNSFBA118044). The authors are grateful
for the useful comments and suggestions of the editors and
reviewers.
[Zn(pbta)0.5(bpp)(H2O)] (6). Compound 6 was prepared as colorless
block crystals by the same synthetic procedure for 1, from ZnSO4·
7H2O (29 mg, 0.1 mmol), H4pbta (22 mg, 0.05 mmol), bpp (11 mg,
0.05 mmol), and 2 mL of H2O/DMF (v/v = 6:4). Yield: 60% (based
on ZnSO4·7H2O). Anal. Calcd for C25H23N2O6Zn: C, 58.55; H, 4.48;
N, 5.46%. Found: C, 58.60; H, 4.40; N, 5.50%. IR (KBr disk, cm−1):
3292 (m), 1622 (s), 1577 (s), 1505 (m), 1452 (m), 1396 (m), 1366
(m), 1266 (w), 1236 (m), 1123 (m), 1097 (m), 1037 (m), 778 (s),
728 (m), 640 (m), 517 (m).
REFERENCES
■
(1) Hagrman, P.; Hagrman, D.; Zubieta, J. Angew. Chem., Int. Ed.
1999, 111, 2798−2848.
(2) Yao, Z. J.; Yu, W. B.; Huang, S. L.; Li, Z. H.; Jin, G. X. J. Am.
Chem. Soc. 2014, 136, 2825−2832.
(3) Huang, S. L.; Lin, Y. J.; Andy Hor, T. S.; Jin, G. X. J. Am. Chem.
Soc. 2013, 135, 8125−8128.
(4) Blake, A.; Champness, N.; Hubberstey, P.; Li, W.; Withersby, M.;
[Zn(H2pbta)(bibm)]·H2O (7). Compound 7 was prepared as
colorless sheet crystals by the same synthetic procedure for 1 was
used, from ZnSO4·7H2O (29 mg, 0.1 mmol), bibm (14 mg, 0.05
mmol), H4pbta (24 mg, 0.05 mmol), and 2 mL of H2O and DMF (v/v
= 6:4). Yield: 48% (based on ZnSO4·7H2O). Anal. Calcd for
C42H32N4O11Zn: C, 60.47; H, 3.83; N, 6.71%. Found: C, 60.56; H,
3.96; N, 6.82%. IR (KBr disk, cm−1): 3474 (m), 1706 (s), 1621 (s),
1571 (s), 1521 (s), 1452 (m), 1395 (m), 1310 (m), 1259 (m), 1125
(m), 1065 (m), 1041 (m), 1036 (m), 964 (m), 824 (m), 778 (s), 729
(m), 657 (m).
X-ray Structure Determinations. Crystal data for 1−7 were
collected on a Bruker ApexII smart using graphite monochromated
Mo−Kα (λ = 0.71073 Å). The collected data were reduced by the
program ApexII. The crystal structures of 1−7 were solved by direct
methods and refined on F2 by full-matrix least-squares methods with
the SHELXL-97 program.100 All non-hydrogen atoms were refined
anisotropically. The H (H5a) atom of the protonated carboxyl group
in 5 was located in the different maps. The H atoms of the lattice water
molecules in 1, 5, and 7 were not located in the different Fourier maps
but were added to their formula. Crystallographic data and refinement
details for 1−7 are summarized in Table 1.
Schroder, M. Coord. Chem. Rev. 1999, 183, 117−138.
̈
(5) Moulton, B.; Zaworotko, M. Chem. Rev. 2001, 101, 1629−1658.
(6) Evans, O.; Lin, W. B. Acc. Chem. Res. 2002, 35, 511−522.
(7) Yaghi, M.; OKeeffe, M.; Ockwig, N.; Chae, H.; Eddaoudi, M.;
Kim, J. Nature 2003, 423, 705−714.
(8) Muller, A.; Das, S.; Talismanov, S.; Roy, S.; Beckmann, E.; Bogge,
̈
̈
H.; Schmidtmann, M.; Merca, A.; Berkle, A.; Allouche, L.; Zhou, Y.;
Zhang, L. Angew. Chem., Int. Ed. 2003, 115, 5193−5198.
(9) Rao, C.; Natarajan, S.; Vaidhyanathan, R. Angew. Chem., Int. Ed.
2004, 116, 1490−1521.
(10) Hu, F. L.; Wang, S. L.; Wu, B.; Yu, H.; Wang, F.; Lang, J. P.
CrystEngComm 2014, 16, 6354−6363.
́
(11) Beziau, A.; Baudron, S. A.; Pogozhev, D.; Fluck, A.; Hosseini, M.
W. Chem. Commun. 2012, 48, 10313−10315.
(12) Chen, X. Y.; Marchal, C.; Filinchuk, Y.; Imbert, D.; Mazzanti, M.
Chem. Commun. 2008, 3378−3380.
(13) Bu, X. H.; Chen, W.; Hou, W. F.; Du, M.; Zhang, R. H.; Brisse,
F. Inorg. Chem. 2002, 41, 3477−3482.
(14) Liu, Y. Y.; Ma, J. F.; Yang, J.; Su, Z. M. Inorg. Chem. 2007, 46,
3027−3037.
(15) Zhang, L. P.; Ma, J. F.; Yang, J.; Liu, Y. Y.; Wei, G. H. Cryst.
Growth Des. 2009, 9, 4660−4673.
ASSOCIATED CONTENT
* Supporting Information
■
(16) Suenaga, Y.; Yan, S. G.; Wu, L. P.; Ion, I.; Kuroda-Sowa, T.;
Maekawa, M.; Munakata, M. J. Chem. Soc., Dalton Trans. 1998, 1121−
1126.
S
Crystal structural data for 1−7 (CCDC 1007803−100787,
100789, and 1007810) in CIF, additional figures and details of
characterization (pdf). The Supporting Information is available
free of charge on the ACS Publications website at DOI:
10.1021/acs.cgd.5b00642.
(17) Hirsch, K. A.; Wilson, S. R.; Moore, J. S. Inorg. Chem. 1997, 36,
2960−2968.
(18) Bu, X. H.; Xie, Y. B.; Li, J. R.; Zhang, R. Inorg. Chem. 2003, 42,
7422−7430.
(19) Knight, J. C.; Alvarez, S.; Amoroso, A. J.; Edwards, P. G.; Singh,
N. Dalton Trans. 2010, 39, 3870−3883.
AUTHOR INFORMATION
Corresponding Authors
*(J.-P.L.) Tel./Fax: +86 512 65880328; e-mail: jplang@suda.
edu.cn.
■
(20) Zhang, X.; Guo, C.; Yang, Q.; Wang, W.; Liu, W.; Kang, B.; Su,
C. Chem. Commun. 2007, 4242−4244.
(21) Hu, F. L.; Wu, W.; Liang, P.; Gu, Y. Q.; Zhu, L. G.; Wei, H.;
Lang, J. P. Cryst. Growth Des. 2013, 13, 5050−5061.
(22) Qin, C.; Wang, X.; Carlucci, L.; Tong, M.; Wang, E.; Hu, C.; Xu,
L. Chem. Commun. 2004, 1876−1877.
*(Q.H.) Tel./Fax: +86 771 3267118; e-mail: huangqinpeking@
163.com.
(23) Du, M.; Wang, X. G.; Zhang, Z. H.; Tang, L. F.; Zhao, X. J.
CrystEngComm 2006, 8, 788−793.
Author Contributions
#S.L.W. and F.-L.H. contributed equally to this work
(24) Liu, D.; Ren, Z. G.; Li, H. X.; Lang, J. P.; Li, N. Y.; Abrahams, B.
F. Angew. Chem., Int. Ed. 2010, 49, 4767−4770.
(25) Hu, F. L.; Wang, S. L.; Lang, J. P.; Abrahams, B. F. Sci. Reports
2014, 4, 6815−6820.
Notes
The authors declare no competing financial interest.
(26) Liu, D.; Lang, J. P. CrystEngComm 2014, 16, 76−81.
(27) Blake, A.; Champness, N.; Khlobystov, A.; Lemenovskii, D.; Li,
ACKNOWLEDGMENTS
■
The authors acknowledge the financial support from the
National Natural Science Foundation of China (21463006,
21171124, 21373142 and 51203027). J.-P.L. highly appreciates
the financial support from the Qing-Lan Project and the “333”
Project of Jiangsu Province, the Priority Academic Program
Development of Jiangsu Higher Education Institutions, and the
W.; Schroder, M. Chem. Commun. 1997, 2027−2028.
̈
(28) Yang, J.; Ma, J.; Batten, S.; Su, Z. Chem. Commun. 2008, 2233−
2235.
(29) Yao, Q.; Ju, Z.; Zhang, J. Inorg. Chem. 2009, 48, 1266−1268.
(30) He, X.; Lu, X. P.; Li, M. X.; Morris, R. E. Cryst. Growth Des.
2013, 13, 1649−1654.
I
DOI: 10.1021/acs.cgd.5b00642
Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design
Article
(31) He, X.; Lu, X. P.; Ju, Z. F.; Li, C. J.; Zhang, Q. K.; Li, M. X.
CrystEngComm 2013, 15, 2731−2734.
(66) Yang, Q. X.; Chen, X. Q.; Cui, J. H.; Hu, J. S.; Zhang, M. D.;
Qin, L.; Wang, G. F.; Lu, Q. Y.; Zheng, H. G. Cryst. Growth Des. 2012,
12, 4072−4082.
(32) Sun, D.; Han, L. L.; Yuan, S.; Deng, Y. K.; Xu, M. Z.; Sun, D. F.
Cryst. Growth Des. 2013, 13, 377−385.
(67) Xu, L.; Guo, G. C.; Liu, B.; Wang, M. S.; Huang, J. S. Inorg.
Chem. Commun. 2004, 7, 1145−1149.
(33) Parshamoni, S.; Sanda, S.; Jena, H. M.; Tomar, K.; Konar, S.
Cryst. Growth Des. 2014, 14, 2022−2033.
(34) Du, M.; Jiang, X. J.; Zhao, X. J. Inorg. Chem. 2006, 45, 3998−
4006.
(68) Chen, S. M.; Zhang, J. A.; Lu, C. Z. CrystEngComm 2007, 9,
390−393.
(69) Valeur, B. Molecular Fluorescence: Principles and Application;
Wiley-VCH: Weinheim, 2002.
(35) Martin, D. P.; Staples, R. J.; LaDuca, R. L. Inorg. Chem. 2008, 47,
(70) Zheng, S. L.; Yang, J. H.; Yu, X. L.; Chen, X. M.; Wang, W. T.
9754−9756.
Inorg. Chem. 2004, 43, 830−838.
(71) He, J. H.; Yu, J. H.; Zhang, Y. T.; Pan, Q. H.; Xu, R. R. Inorg.
Chem. 2005, 44, 9279−9282.
(72) Liang, X. Q.; Zhou, X. H.; Chen, C.; Xiao, H. P.; Li, Y. Z.; Zou,
J. L.; You, X. Z. Cryst. Growth Des. 2009, 9, 1041−1053.
(73) Bunz, U. H. F. Chem. Rev. 2000, 100, 1605−1644.
(74) Frisch, M.; Cahill, C. L. Dalton Trans. 2005, 8, 1518−1523.
(75) Yu, G.; Yin, S.; Liu, Y.; Shuai, Z.; Zhu, D. J. Am. Chem. Soc.
2003, 125, 14816−14824.
(36) LaDuca, R. L. Coord. Chem. Rev. 2009, 253, 1759−1792.
(37) Yao, X. Q.; Cao, D. P.; Hu, J. S.; Li, Y. Z.; Guo, Z. J.; Zheng, H.
G. Cryst. Growth Des. 2011, 11, 231−239.
(38) Li, B.; Zang, S. Q.; Ji, C.; Du, C. X.; Hou, H. W.; Mak, T. C. W.
Dalton Trans. 2011, 40, 788−792.
(39) Fang, S. M.; Hu, M.; Zhang, Q.; Du, M.; Liu, C. S. Dalton Trans.
2011, 40, 4527−4541.
(40) Gu, J. Z.; Gao, Z. Q.; Tang, Y. Cryst. Growth Des. 2012, 12,
3312−3323.
(76) Chen, S. S.; Zhao, Y.; Fan, J.; Okamura, T.; Bai, Z. S.; Chen, Z.
H.; Sun, W. Y. CrystEngComm 2012, 14, 3564−3576.
(77) Xu, C. Y.; Li, L. K.; Wang, Y. P.; Guo, Q. Q.; Wang, X. J.; Hou,
H. W.; Fan, Y. T. Cryst. Growth Des. 2011, 11, 4667−4675.
(78) Cheng, P. C.; Kuo, P. T.; Liao, Y. H.; Xie, M. Y.; Hsu, W.; Chen,
J. D. Cryst. Growth Des. 2013, 13, 623−632.
(41) Su, Z.; Fan, J.; Chen, M.; Okamura, T.; Sun, W. Y. Cryst. Growth
Des. 2011, 11, 1159−1169.
(42) Shi, D. B.; Ren, Y. W.; Jiang, H. F.; Cai, B. W.; Lu, J. X. Inorg.
Chem. 2012, 51, 6498−6506.
(43) Ma, L. F.; Wang, L. Y.; Wang, Y. Y.; Batten, S. R.; Wang, J. G.
Inorg. Chem. 2009, 48, 915−924.
(79) Gong, Y.; Wu, T.; Lin, J. H.; Wang, B. S. CrystEngComm 2012,
14, 5649−5656.
(44) Ma, L. F.; Li, C. P.; Wang, L. Y.; Du, M. Cryst. Growth Des.
2011, 11, 3309−3312.
(80) Bai, Y.; He, G. J.; Zhao, Y. G.; Duan, C. Y.; Dang, D. B.; Meng,
Q. J. Chem. Commun. 2006, 1530−1532.
(45) Liu, T. F.; Lu, J. A.; Tian, C. B.; Cao, M. N.; Lin, Z. J.; Cao, R.
Inorg. Chem. 2011, 50, 2264−2271.
(81) Zou, J. P.; Peng, Q.; Wen, Z.; Zeng, G. S.; Xing, Q. J.; Guo, G.
C. Cryst. Growth Des. 2010, 10, 2613−2619.
(46) Schaate, A.; Klingelhofer, S.; Behrens, V.; Wiebcke, M. Cryst.
Growth Des. 2008, 8, 3200−3205.
(82) Wang, X. L.; Luan, J.; Sui, F. F.; Lin, H. Y.; Liu, G. C.; Xu, C.
Cryst. Growth Des. 2013, 13, 3561−3576.
(47) Liu, Y.; Qi, Y.; Lv, Y. Y.; Che, Y. X.; Zheng, J. M. Cryst. Growth
Des. 2009, 9, 4797−4801.
(83) Barbieri, A.; Accorsi, G.; Armaroli, N. Chem. Commun. 2008,
2185−2193.
(48) Li, Z. X.; Hu, T. L.; Ma, H.; Zeng, Y. F.; Li, C. J.; Tong, M. L.;
Bu, X. H. Cryst. Growth Des. 2010, 10, 1138−1144.
(49) Yang, J.; Ma, J. F.; Battern, S. R.; Su, Z. M. Chem. Commun.
2008, 2221−2223.
(84) Yang, G. P.; Wang, Y. Y.; Zhang, W. H.; Fu, A. Y.; Liu, R. T.;
Lermontova, E. K.; Shi, Q. Z. CrystEngComm 2010, 12, 1509−1517.
(85) Chang, Z.; Zhang, A. S.; Hu, T. L.; Bu, X. H. Cryst. Growth Des.
2009, 9, 4840−4846.
(50) Pachfule, P.; Dey, C.; Panda, T.; Banarjee, R. CrystEngComm
2010, 12, 1600−1609.
(51) Cao, X. Y.; Yao, Y. G.; Batten, S. R.; Ma, E.; Qin, Y. Y.; Zhang,
J.; Zhang, R. B.; Cheng, J. K. CrystEngComm 2009, 11, 1030−1036.
(52) Pan, Y. J.; Ford, W. T. J. Org. Chem. 1999, 64, 8588−8593.
(53) Kalsi, P. S. Spectroscopy Of Organic Compounds; New Age
International: New Delhi. 2008.
(86) Wang, H. Y.; Gao, S.; Huo, L. H.; Ng, S. W.; Zhao, J. G. Cryst.
Growth Des. 2008, 8, 665−670.
(87) Gong, Y.; Wua, T.; Lin, J. H. CrystEngComm 2012, 14, 3727−
3736.
(88) Paul, A. K.; Madras, G.; Natarajan, S. Phys. Chem. 2009, 11,
11285−11296.
(89) Yang, G. S.; Zang, H. Y.; Lan, Y. Q.; Wang, X. L.; Jiang, C. J.; Su,
Z. M.; Zhu, L. D. CrystEngComm. 2011, 13, 1461−1466.
(90) Tzeng, B. C.; Chiu, T. H.; Chen, B. S.; Lee, G. H. Chem.Eur.
J. 2008, 14, 5237−5245.
(91) Luo, F.; Yuan, Z. Z.; Feng, X. F.; Batten, S. R.; Li, J. Q.; Luo, M.
B.; Liu, S. J.; Xu, W. Y.; Sun, G. M.; Song, Y. M.; Huang, H. X.; Tian,
X. Z. Cryst. Growth Des. 2012, 12, 3392−3396.
(92) Liu, B.; Yang, J.; Yang, G. C.; Ma, J. F. Inorg. Chem. 2013, 52,
84−94.
(93) Wang, F.; Li, F. L.; Xu, M. M.; Yu, H.; Zhang, J. G.; Xia, H. T.;
Lang, J. P. J. Mater. Chem. A 2015, 3, 5908−5916.
(94) Dai, M.; Su, X. R.; Wang, X.; Wu, B.; Ren, Z. G.; Zhou, X.; Lang,
J. P. Cryst. Growth Des. 2014, 14, 240−248.
(95) Li, D. X.; Ni, C. Y.; Chen, M. M.; Dai, M.; Zhang, W. H.; Yan,
W. Y.; Qi, H. X.; Ren, Z. G.; Lang, J. P. CrystEngComm 2014, 16,
2158−2167.
(96) Wen, T.; Zhang, D. X.; Zhang, J. Inorg. Chem. 2013, 52, 12−14.
(97) Kan, W. Q.; Liu, B.; Yang, J.; Liu, Y. Y.; Ma, J. F. Cryst. Growth
Des. 2012, 12, 2288−2298.
(98) Guo, J.; Ma, J. F.; Li, J. J.; Yang, J.; Xing, S. X. Cryst. Growth Des.
2012, 12, 6074−6082.
(99) Wang, X. L.; Sui, F. F.; Lin, H. Y.; Zhang, J. W. Cryst. Growth
Des. 2014, 14, 3438−3452.
(54) Ma, T.; Li, M. X.; Wang, Z. X.; Zhang, J. C.; Shao, M.; He, X.
Cryst. Growth Des. 2014, 14, 4155−4165.
(55) Bellamy, L. J. The Infrared Spectra of Compound Molecules;
Wiley: New York. 1958.
(56) Zhang, F. M.; Zou, X. Y.; Yan, P. F.; Li, G. M. Cryst. Growth Des.
2015, 15, 1249−1258.
(57) Arıcı, M.; Yesi
̧ lel, O. Z.; Tas,̧ M. Cryst. Growth Des. 2015, 15,
3024−3031.
(58) Du, P.; Yang, Y.; Yang, J.; Liu, Y. Y.; Ma, J. F. CrystEngComm
2013, 15, 6986−7002.
(59) Ji, C. C.; Qin, L.; Li, Y. Z.; Guo, Z. J.; Zheng, H. G. Cryst.
Growth Des. 2011, 11, 480−487.
(60) Batten, S. R.; Robson, R. Angew. Chem., Int. Ed. 1998, 37, 1460−
1494.
(61) Batten, S. R. CrystEngComm 2001, 3, 67−72.
(62) Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. Rev. 2003,
246, 247−289.
(63) Goodgame, D. M. L.; Menzer, S.; Smith, A. M.; Williams, D. J.
Angew. Chem., Int. Ed. 1995, 34, 574−575.
(64) Luo, F.; Yang, Y. T.; Che, Y. X.; Zheng, J. M. CrystEngComm
2008, 10, 981−982.
(65) Lan, Y. Q.; Li, S. L.; Qin, J. S.; Du, D. Y.; Wang, X. L.; Su, Z. M.;
Fu, Q. Inorg. Chem. 2008, 47, 10600−10610.
J
DOI: 10.1021/acs.cgd.5b00642
Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design
Article
(100) Sheldrick, G. M. SHELXS-97, Program for Solution of Crystal
Structures; University of Gottingen: Germany, 1997.
̈
K
DOI: 10.1021/acs.cgd.5b00642
Cryst. Growth Des. XXXX, XXX, XXX−XXX