Group position-dependent structurally diverse coordination compounds based on isomeric Ligands

Article abstract of DOI:10.1071/CH14442

Two isomeric ligands Htzpya and Hpytza (Htzpya≤3-(5-tetrazolyl)pyridine-1-acetic acid, Hpytza≤5-(3-pyridyl)tetrazole-2-acetic acid) have been selected to react with DyCl3·6H2O or PrCl3·6H2O under hydrothermal conditions, resulting in the formation of four new coordination compounds, mononuclear [Dy(tzpya)2(H2O)5]Cl·4H2O (1), dinuclear [Pr2(tzpya)2(H2O)12]Cl4·2H2O (2), and two one-dimensional polymers [Dy(pytza)2Cl(H2O)2]n (3) and [Pr(pytza)2Cl(H2O)2]n (4), whose structures are controlled by the different positions of the carboxylate group. These compounds were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compounds 1-4 are self-assembled to form three-dimensional network structures by hydrogen bonding interactions. Furthermore, the luminescence properties were also investigated at room temperature in the solid state.

Full text of DOI:10.1071/CH14442

CSIRO PUBLISHING
Aust. J. Chem. 2015, 68, 889–895
Full Paper
http://dx.doi.org/10.1071/CH14442
Group Position-Dependent Structurally Diverse
Coordination Compounds Based on Isomeric Ligands
A
A
A
A
Jian Hua Zou, Jian Nan Zhu, Han Jie Cui, Zhong Wang,
A
A
A
A
,
A B
Da Liang Zhu, He Tian, Fei Fei Zhang, Jing Wang, Qiao Yun Li,
,
A B
and Gao Wen Yang
A
Department of Chemistry and Material Engineering, Jiangsu Laboratory of Advanced
Functional Materials, Changshu Institute of Technology, Changshu, 215500, China.
Corresponding authors. Emails: liqiaoyun61@126.com; ygwsx@126.com
B
Two isomeric ligands Htzpya and Hpytza (Htzpya ¼ 3-(5-tetrazolyl)pyridine-1-acetic acid, Hpytza ¼ 5-(3-pyridyl)
tetrazole-2-acetic acid) have been selected to react with DyCl ꢀ6H O or PrCl ꢀ6H O under hydrothermal conditions,
3
2
3
2
resulting in the formation of four new coordination compounds, mononuclear [Dy(tzpya) (H O) ]Clꢀ4H O (1), dinuclear
2
2
5
2
[
(
Pr (tzpya) (H O) ]Cl ꢀ2H O (2), and two one-dimensional polymers [Dy(pytza) Cl(H O) ] (3) and [Pr(pytza) Cl
2 2 n
2
2
2
12
4
2
2
2
2 n
2
H O) ] (4), whose structures are controlled by the different positions of the carboxylate group. These compounds were
characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray
diffraction. Compounds 1–4 are self-assembled to form three-dimensional network structures by hydrogen bonding
interactions. Furthermore, the luminescence properties were also investigated at room temperature in the solid state.
Manuscript received: 1 April 2014.
Manuscript accepted: 26 August 2014.
Published online: 18 November 2014.
Introduction
the final structure, leading to unpredictable results and adding to
the novelty of existing structures. By reacting Htzpya and
Hpytza with DyCl ꢀ6H O or PrCl ꢀ6H O under hydrothermal
Metal-organic frameworks (MOFs) have attracted much atten-
tion for exploration over the past decades, owing to not only
their diversity in structure, but also their tunable properties as
3
2
3
2
conditions, four new coordination complexes, [Dy(tzpya)2
[
1]
potentially functional materials in the fields of luminescence,
(H O) ]Clꢀ4H O (1), [Pr (tzpya) (H O) ]Cl ꢀ2H O (2), [Dy
2
5
2
2
2
2
12
4
2
[
2]
[3]
ferroelectric, absorption, and heterogeneous catalysis.
[4]
(pytza) Cl(H O) ] (3), and [Pr(pytza) Cl(H O) ] (4) were
2 2 2 n 2 2 2 n
Among various ligands, to the best of our knowledge, tetrazole-
containing carboxylic acids are outstanding building blocks to
construct novel coordination architectures including mono-, bi-,
tri-, or multinuclear and one-, two-, or three-dimensional net-
obtained. Herein, we report their synthesis, crystal structure and
luminescence properties along with the influence of the different
positions of the carboxylate group.
[5]
Experimental
works. However, it is still a challenge to predict the final
supramolecular architectures of the desired crystalline products
because of many factors, for example, the coordination ability of
the metal centre, the nature of the ligands, and the metal-to-
ligand ratio that may have great impacts on the self-assembly
Materials and Instrumentations
General chemicals were commercially available reagents of
analytical grade used without further purification. The ele-
mental analyses for C, H, and N were performed on an EA1110-
CHNS elemental analyzer. The infrared (IR) spectra were
obtained on a NICOLET 380 spectrometer using KBr disks
[6]
process. One of the key factors to obtaining the targeted
molecules is via appropriate selection of the ligand; investiga-
tions on structurally diverse coordination compounds which are
group position dependent have been limited. In this paper, two
isomeric tetrazole-containing carboxylic acid ligands, Htzpya
and Hpytza, where Htzpya ¼ 3-(5-tetrazolyl)pyridine-1-acetic
acid and Hpytza ¼ 5-(3-pyridyl)tetrazole-2-acetic acid (Fig. 1)
have been chosen to construct intriguing structures. The two
ligands that comprise both nitrogen atoms from the pyridyl and
tetrazolyl rings and oxygen atoms from the carboxylate group
have high possibilities to display various coordination modes,
and the abundant nitrogen and oxygen atoms may participate in
ꢁ
1
in the range of 4000–400 cm . Photoluminescence analysis
was performed on an F-4600 fluorescence spectrometer.
CH COOH
2
N
N
N
N
CH COOH
2
N
ϩ
Ϫ
N
N
N
N
N
Htzpya
Hpytza
[7]
hydrogen bonds to stabilize the supramolecular assemblies.
Furthermore, the position of the carboxylate group can influence
Fig. 1. Schematic drawing for Htzpya and Hpytza.
Journal compilation Ó CSIRO 2015
www.publish.csiro.au/journals/ajc

8
90
J. H. Zou et al.
Single-crystal X-ray diffraction was carried out on a Rigaku
SCXmini-CCD diffractometer. Thermogravimetric analysis
(s), 3058 (w), 3007 (w), 1611 (s), 1567 (s), 1444 (s), 1419 (s),
1393 (m), 1378 (m), 1308 (m), 1197 (w), 1037 (m), 1004 (w),
827 (m). Anal. Calc. for C H ClN O Pr: C 30.96, H 2.60,
(TGA) was carried out on a Perkin–Elmer TGA 7 thermo-
gravimetric analyzer; the samples were heated at a rate of
1
6
16
10 6
N 22.57. Found: C 30.90, H 2.68, N 22.55 %.
ꢁ1
108C min from room temperature to 8008C under nitrogen
atmosphere.
X-Ray Crystallography
Suitable single crystals of complexes 1–4 were mounted on a
Rigaku SCXmini-CCD diffractometer equipped with a graph-
Synthesis and Characterization of Htzpya and Hpytza
5
reactions by treating 3-cyanopyridine with NaN in toluene in
the presence of triethylammonium chloride.
-(3-Pyridyl) tetrazole was prepared by [2þ3] cycloaddition
ite-monochromated MoKa radiation (l ¼ 0.71073 A˚ ) at 291–
3
293 K. All absorption corrections were performed using the
Crystal-Clear programs. The crystal structures of 1–4 were
2
solved by direct methods and refined on F by full-matrix
least-squares using anisotropic displacement parameters for all
At 708C, the reaction of 5-(3-pyridyl) tetrazole with chlor-
oacetic acid in methanolic potassium hydroxide solution gave
mostly N(pyridine) products 3-(5-tetrazolyl)pyridine-1-acetato
potassium salt The reaction of 5-(3-pyridyl) tetrazole with ethyl
bromoacetate in methanolic potassium hydroxide solution gave
mostly H(tetrazole)-substituted products 5-(3-pyridyl)tetrazole-
[
9]
non-hydrogen atoms. For 1–4, important crystal data and
collection and refinement parameters are summarized in
Table 1, selected bond lengths and angles are given in Table 2,
and hydrogen-bonding geometry are listed in Table 3.
[
8]
2
-acetato potassium salt. Then, the pH of the solution was
adjusted to 2 with HCl (12 M). After cooling to room tempera-
ture, the precipitate was filtered off, washed with methanol
Results and Discussions
General Characterization of 1–4
(
(
2 ꢂ 30 mL) and dried, forming the corresponding acid products
Compounds 1–4 are stable towards oxygen and moisture. The
elemental analysis of 1–4 is consistent with their chemical
formula. In the IR spectra of 1–4, strong absorptions at 1644–
Htzpya or Hpytza). Htzpya: a 80 % yield was obtained based on
ꢁ1
Hpytz consumed. nmax (KBr)/cm 3426 (s), 1730 (s), 1570 (s),
1
1
C 46.83, H 3.44, N 34.13. Found: C 46.70, H 3.50, N 34.25 %.
Hpytza: a 82 % yield was obtained based on Hpytz consumed.
nmax (KBr)/cm 3261 (s), 3102 (s), 1731 (w), 1544 (m), 1512
(
(
420 (s), 1396 (m), 1257 (m), 1209 (m), 1146 (w), 1064 (m),
018 (w), 905 (w), 868 (w), 766 (w). Anal. Calc. for C H O N :
ꢁ1
1
carboxylate group were observed.
611 cm
corresponding to the n(COO) vibration of the
8
7 2 5
[10]
IR spectra of the prod-
ꢁ1
ucts showed typical peaks (1426–1601 cm ) corresponding to
ꢁ1
the tetrazole and pyridyl group. Peaks at 3351–3443 cm are
ascribed to the O-H vibration of water molecules. The identities
of 1–4 are confirmed by X-ray crystallography.
ꢁ1
w), 1486 (w), 1457 (m), 1289 (m), 1229 (m), 1176 (w), 1094
w), 958 (w), 790 (w). Anal. Calc. for C H O N : C 46.83, H
8
7 2 5
3
.44, N 34.13. Found: C 46.75, H 3.40, N 34.18 %.
Crystal Structure of [Dy(tzpya) (H O) ]Clꢀ4H O (1)
2
2
5
2
Synthesis of [Dy(tzpya) (H O) ]Clꢀ4H O (1)
Compound 1 crystallizes in monoclinic space group C2/c. As is
III
shown in Fig. 2, each Dy centre is nine-coordinated by four
2
2
5
2
and [Pr (tzpya) (H O) ]Cl ꢀ2H O (2)
2
2
2
12
4
2
carboxylate-O from two independent tzpya ligands (O1, O2,
O1A, O2A) and five oxygen atoms from five water molecules
Htzpya (0.0237 g, 0.1 mmol) was dissolved in 0.5 mL distilled
water and the pH was adjusted to 5 with KOH, then a mixture
of 3 mL ethanol and LnCl ꢀ6H O (0.0377 g, 0.1 mmol Ln ¼
(O3, O3A, O4, O4A, O5), forming a distorted mono-capped
3
2
square anti-prism coordination arrangement. Each tzpya
adopts a bidentate chelating mode to coordinate with the same
III
Dy centre, thereby displaying a mononuclear structure. The
Dy (1); 0.0355 g, 0.1 mmol Ln ¼ Pr(2)) were added. The resulting
mixture was sealed in a 25 mL Teflon-lined stainless container
and heated at 1208C for 48 h. Colourless block crystals of 1 and
light yellow crystals of 2 were acquired. For 1, a yield of 42 %
structure of compound 1 is the same as that of previously
but is different from that of
III
reported Y -tzpya compound,
[11]
3
þ
ꢁ1
based on Dy consumed was obtained. nmax (KBr)/cm 3413
s), 1740 (w), 1644 (s), 1610 (s), 1520 (w), 1478 (w), 1405 (m),
308 (w), 1197 (w), 1141 (w), 1047 (w), 984 (w), 942 (w). Anal.
Calc. for C H N O Dy: C 26.22, H 4.13, N 19.11. Found:
DyAg(oxalate)(2-pzc) ꢀH O (2-pzc ¼ pyrazine-2-carboxylate)
(
1
2
2
because 2-pzc acts as a tridentate ligand via its two nitrogen
atoms from the pyrazine ring and one carboxylate oxygen atom
1
6 30 10 13
[
to form a three-dimensional (3D) network. Internal hydrogen
12]
C 26.15, H 4.20, N 19.10 %. For 2, a yield of 50 % based on
3
Pr consumed was obtained. nmax (KBr)/cm 3389 (s), 1628
þ
ꢁ1
bonds exist to stabilize the molecular assembly. Neighbouring
þ
[Dy(tzpya) (H O) ] cations are further held together via the
p–p stacking interactions between the pyridyl and tetrazole
(s),1598 (s),1525 (m),1438 (s),1406 (s),1305 (m),1195 (m),1139
2
2
5
(w), 1022 (w), 930 (w), 829 (w), 730 (m), 700 (m), 621 (m).
Anal. Calc. for C H Cl N O Pr : C 17.72, H 3.72, N 12.92.
Found: C 17.69, H 3.75, N 12.96 %.
˚
rings (3.848 and 4.182 A) from neighbouring tzpya ligands to
1
6
40
4
10 18
2
generate a two-dimensional (2D) layer. Adjacent layers are
linked together via intermolecular hydrogen bonds to form a 3D
supramolecular network (Fig. S1, Supplementary Material;
Table 3).
Synthesis of [Dy(pytza) Cl(H O) ] (3) and [Pr(pytza) Cl
2
2
2 n
2
(
H O) ] (4)
2 2 n
Similar methods were adopted to prepare 3 and 4 except that
Htzpya was replaced by Hpytza. Colourless crystals of 3 and
light yellow crystals of 4 were obtained. For 3, a yield of 55 %
Crystal Structure of [Pr (tzpya) (H O) ]Cl ꢀ2H O (2)
2
2
2
12
4
2
The X-ray analysis reveals that compound 2 crystallizes in
monoclinic space group C2/c and the asymmetric unit contains
only half of [Pr (tzpya) (H O) ]Cl ꢀ2H O molecule. As shown
3
þ
ꢁ1
based on Dy consumed was obtained. nmax (KBr)/cm 3343
m), 3059 (m), 2963 (w), 1629 (s), 1611 (m), 1576 (s), 1451 (s),
419 (s), 1394 (w), 1377 (m), 1313 (m), 1196 (m), 1037 (m), 827
m). Anal. Calc. for C H ClN O Dy: C 29.92, H 2.51, N
(
1
2
2
2
12
4
2
III
in Fig. 3, each Pr centre in a distorted square anti-prism centre
is eight-coordinated by two carboxylate-O atoms from two
(
1
6
16
10 6
III
III
2
1.81. Found: C 30.02, H 2.60, N 21.67 %. For 4, a yield of 53 %
ꢁ1
tzpya ligands (O1, O1A for Pr 1, O2, O2A for Pr 2) and six
oxygen atoms from six water molecules (O3, O3A, O4, O4A,
3þ
based on Pr consumed was obtained. nmax (KBr)/cm 3351

Htzpya- and Hpytza-Based Compounds
891
Table 1. Crystallographic data for 1–4
2
Compound
1
3
4
Empirical formula
Formula mass
Crystal system
Space group
C
16
H
30ClN10
O
13Dy
C
16
H
40
N
10
O
18Cl
4
Pr
2
C
16
H
16ClN10
O
6
Dy
C
16 6
H16ClN10O Pr
768.45
1084.20
642.34
620.75
Monoclinic
C2/c
Monoclinic
C2/c
Monoclinic
C2/c
Monoclinic
C2/c
˚
a [A]
˚
b [A]
˚
c [A]
29.083(6)
12.641(3)
7.9236(16)
100.21(3)
2866.9(11)
4
17.808(4)
14.780(3)
16.051(3)
106.78(3)
4044.7(14)
4
23.408(5)
11.131(2)
8.8964(18)
108.10(3)
2203.3(8)
4
23.702(5)
11.310(2)
8.8580(18)
107.63(3)
2263.0(8)
4
b [8]
˚
3
V [A ]
Z
T [K]
291(2)
291(2)
291(2)
291(2)
ꢁ
3
D
c
[g cm
]
1.780
1.780
1.936
1.822
ꢁ
1
m [mm
Reflections collected
]
2.776
2.720
3.570
2.327
14619
16907
11178
11462
Unique reflections (Rint
)
3295(0.1335)
2382
3555(0.0624)
2965
2527(0.0399)
2418
2590(0.0334)
2489
No. of observations (I . 2s(I))
No. of variables
174
209
157
163
A
R /wR
B
0.0625/0.1082
1.045
0.0587/0.1231
1.175
0.0210/0.0522
1.027
0.0204/0.0469
1.085
C
GOF
˚
ꢁ3
]
ꢁ3
]
D/rmax [e A
1.491
1.702
0.846
0.564
˚
D/rmin [e A
ꢁ1.781
ꢁ0.779
ꢁ0.630
0.697
P
P
A
R ¼ (||F
o
| ꢁ |F
c
||)/ |F
2 2
c
o
|.
P
P
B
2
o
2 2 1/2
o
wR ¼ [ w(F
ꢁ F
) / w(F
2 2
) ]
.
1/2
P
C
2
o
GOF ¼ [ w((F
ꢁ F
c
) )/(n ꢁ P)] , where n ¼ number of reflections and P ¼ total numbers of parameters refined.
III III
O5, O5A for Pr 1, O6, O6A, O7, O7A, O8, O8A for Pr 2).
tridentate or tetradentate ligands via one nitrogen atom and the
carboxylate group in a m1,3-COO or m1,3,3-COO bridging mode,
compound 3 shows a wave-like chain, whereby only the car-
Compared with 1, each tzpya acts as a bidentate bridging ligandto
III
connect two Pr centres via its two carboxylate-O atoms rather
0
III
[15]
than the O,O chelating mode, thereby displaying a binuclear
˚
boxylate oxygen atoms are coordinated to the Dy centre.
structure with PrꢀꢀꢀPr distance of 5.5119 A. Compound 2 is iso-
Furthermore, neighbouring 1D chains are linked together by two
kinds of hydrogen bonding interactions between the coordinated
water and the chloride anion (O3–H3AꢀꢀꢀCl1) and between the
coordinated water and the nitrogen atom of the pyridyl ring
(O3–H3BꢀꢀꢀN5), forming a 3D supramolecular network (Fig. S3,
Supplementary Material; Table 3).
[
13]
structural to [Nd (tzpya) (H O) ]Cl ꢀ2H O. However, com-
2
2
2
12
4
2
pared with [Pr (tza) (H O) ] ꢀ4nH O (tza¼tetrazole-5-acetato)
2
3
2
6 n
2
in which tza ligand acts as pentadentate via one nitrogen atom
and the carboxylate group in a m1,1,3,3-COO bridging mode, only
the carboxylate oxygen atoms are coordinated to the Pr centre,
III
[14]
nitrogen atoms being uncoordinated. Therefore, compound 2
is a simple binuclear cluster rather than a 2D layer. Adjacent
[
kinds of hydrogen bonding interactions to generate a 2D layer
structure. Neighbouring 2D layers are held together through six
kinds of hydrogen bonding interactions to form a 3D supramo-
lecular structure (Fig. S2, Supplementary Material; Table 3).
Crystal Structure of [Pr(pytza) Cl(H O) ] (4)
2
2
2 n
4
þ
Pr (tzpya) (H O) ] cations are linked together through six
2 2 2 12
The X-ray analysis reveals that compound 4 crystallizes in
III
monoclinic space group C2/c. As shown in Fig. 6, each Pr
centre is nine-coordinated by six carboxylate-O atoms from two
independent pytza ligands (O1, O2, O1B, O2A, O1C, O2C), two
oxygen atoms from two water molecules (O3,O3A), and one
chloride anion, displaying a distorted mono-capped square anti-
prism coordination geometry. Two neighbouring Pr centres
are doubly bridged by two carboxylate groups from two pytza
ligands forming a 1D polymeric chain structure extending along
Crystal Structure of [Dy(pytza) Cl(H O) ] (3)
III
2
2
2 n
Compound 3 crystallizes in monoclinic space group C2/c and
the asymmetric unit contains only half of [Dy(pytza) Cl(H O) ]
2
2
2
III
˚
molecule. As is shown in Fig. 4, each Dy centre is seven-
coordinated by four carboxylate-O atoms from two independent
pytza ligands (O1A, O1C, O2, O2B), two oxygen atoms from
two water molecules (O3, O3A) and a chloride anion, forming a
distorted pentagonal bipyrimid coordination geometry. Com-
pared with compound 1, when the carboxylate group transfers
from the pyridyl ring to the tetrazolyl ring, each pytza acts as a
bidentate ligand with a m1,3-COO syn–syn bridging mode to
the c-axis with PrꢀꢀꢀPr distance of 4.5684 A and PrꢀꢀꢀPrꢀꢀꢀPr bite
angle of 151.6248 (Fig. 7). Although Htzpya and Hpytza are
isomeric, the structure changes from dinuclear to a 1D poly-
˚
meric chain. The Pr1–O2 distance of 2.993 A can be considered
as weak coordination bond, therefore pytza is coordinated in an
asymmetric chelate and monoatomic bridging mode. Compared
with [Pr(atza) (CH OH)(H O)Cl] (atza¼5-aminotetrazole-1-
2
3
2
acetato) in which atza displays two coordination modes
and show a 2D layer network, pytza ligand acts as a bridging
ligand via its two carboxylate oxygen atoms, displaying a simple
III
coordinate to two Dy centres, displaying a one-dimensional
(1D) polymeric chain structure extending along the c-axis with
[
16]
˚
DyꢀꢀꢀDy distance of 4.6170 A and DyꢀꢀꢀDyꢀꢀꢀDy bite angle of
1D zig-zag chain structure. Furthermore, adjacent 1D chains
are held together by three kinds of hydrogen bonding inter-
actions between the coordinated water and the chloride anion
1
18.5878 (Fig. 5). Compared with [Dy (tza) (H O) ]ꢀ2H O
2
3
2
6
2
(tza ¼ tetrazole-5-acetic acetato) in which tza acts as both

8
92
J. H. Zou et al.
˚
Table 2. Selected bond distances [A] and angles [8] for 1–4
Table 2. (Continued)
[
Dy(tzpya) (H O) O (1)
2
2
5
]Clꢀ4H
2
[Pr(pytza)
2
Cl(H
2
O)
2
]
n
(4)
Dy1–O4A
Dy1–O5
2.372(2)
2.379(2)
2.406(2)
2.420(2)
2.497(2)
79.57(3)
140.2(11)
139.28(10)
71.10(6)
80.51(7)
73.78(7)
89.73(8)
73.78(7)
89.73(8)
80.51(7)
89.73(8)
147.46(10)
72.90(12)
69.78(13)
144.15(13)
72.90(12)
111.9(12)
Dy1–O4
2.372(2)
2.406(2)
2.420(2)
2.497(5)
xx
O3–Pr1–O1A
O3A–Pr1–O2
O1–Pr1–O2
76.42(6)
O1–Pr1–O1A
166.86(7)
73.77(5)
109.50(5)
156.01(8)
146.39(4)
96.57(4)
78.00(4)
130.06(5)
135.33(5)
62.06(5)
130.06(5)
135.33(5)
62.06(5)
77.75(3)
Dy1–O3
128.73(19)
73.37(6)
73.37(5)
146.39(4)
96.57(4)
78.00(4)
73.13(5)
48.50(6)
112.35(5)
77.75(3)
73.13(5)
48.50(5)
112.35(5)
155.50(7)
O3–Pr1–O2
Dy1–O3A
Dy1–O2A
Dy1–O1A
Dy1–O2
O1A–Pr1–O2
O2–Pr1–O2C
O3–Pr1–Cl1
O1A–Pr1–Cl1
O2C–Pr1–Cl1
O3–Pr1–O2
Dy1–O1
O1A–Pr1–O2C
O3A–Pr1–Cl1
O1–Pr1–Cl1
O2–Pr1–Cl1
O3–Pr1–O2
xx
O4–Dy1–O4A
O4A–Dy1–O5
O4–Dy1–O3
O5–Dy1–O3
O4–Dy1–O2
O5–Dy1–O2
O3–Dy1–O2
O5–Dy1–O2
O3–Dy1–O2
O4–Dy1–O5
O4A–Dy1–O3
O4–Dy1–O3A
O3A–Dy1–O3
O4A–Dy1–O2
O3A–Dy1–O2
O4–Dy1–O2A
O3A–Dy1–O2
O4–Dy1–O2A
O5–Dy1–O2A
O3–Dy1–O2A
O4–Dy1–O1A
O5–Dy1–O1A
O3–Dy1–O1A
O2A–Dy1–O1A
O4A–Dy1–O1
O3A–Dy1–O1A
140.23
74.9
75.0
O1–Pr1–O2
O1A–Pr1–O2
O2C–Pr1–O2
O3A–Pr1–O2A
O1–Pr1–O2A
O2–Pr1–O2A
Cl1–Pr1–O2A
142.19(11)
126.54(7)
79.82(9)
126.54(7)
79.82(9)
126.54(7)
73.68(9)
79.82(9)
126.07(13)
111.90(12)
126.00(13)
53.05(13)
73.72(12)
126.00(12)
O2C–Pr1–O2
Cl1–Pr1–O2
O3–Pr1–O2A
O1A–Pr1–O2A
O2C–Pr1–O2A
O2–Pr1–O2A
O4A–Dy1–O2A
O3A–Dy1–O2A
O2–Dy1–O2A
O4A–Dy1–O1A
O3A–Dy1–O1A
O2–Dy1–O1A
O4–Dy1–O1
Symmetry codes.
For 1 – A: ꢁx, y, 0.5 ꢁ z.
For 2 – A: 1 ꢁ x, y, 0.5 ꢁ z.
For 3 – A: x, 1 ꢁ y, ꢁ0.5 þ z; B: 1 ꢁ x, y, 1.5 ꢁ z; C: 1 ꢁ x, 1 ꢁ y, 1 ꢁ z.
For 4 – A: 1 ꢁ x, ꢁy, 1 ꢁ z; B: 1 ꢁ x, y, 0.5 ꢁ z; C: x, ꢁy, 0.5 þ z.
O5–Dy1–O1
[
Pr
2
(tzpya)
2
(H
2
O)12]Cl
4
ꢀ2H
2
O (2)
Pr1–O1
Pr1–O6
Pr2–O2
Pr2–O4
2.381(6)
2.482(2)
2.423(2)
2.469(2)
90.5(3)
Pr1–O7
2.441(2)
2.507(2)
Table 3. Hydrogen-bonding geometry for 1–4
Pr1–O8
Pr2–O3
2.459(2)
˚
D–H [A]
HꢀꢀꢀA [ A˚ ]
DꢀꢀꢀA [ A˚ ]
D–HꢀꢀꢀA
Dy(tzpya)
D–HꢀꢀꢀA [8]
Pr2–O5
2.504(2)
O1A–Pr1–O1
O1–Pr1–O7
O1–Pr1–O6A
O1–Pr1–O6
O7A–Pr1–O6
O1A–Pr1–O8
O7–Pr1–O8
O6A–Pr1–O8
O8–Pr1–O8A
O2–Pr2–O2A
O2–Pr2–O3
O2–Pr2–O4
O3A–Pr2–O4
O4–Pr2–O4A
O3–Pr2–O5A
O2–Pr2–O5
O4–Pr2–O5
O1A–Pr1–O7
O7–Pr1–O7A
O7A–Pr1–O6A
O7–Pr1–O6
O6A–Pr1–O6
O1–Pr1–O8
O7A–Pr1–O8
O6–Pr1–O8
O5A–Pr2–O5
O2–Pr2–O3A
O3A–Pr2–O3
O2A–Pr2–O4
O3–Pr2–O4
O2–Pr2–O5A
O4–Pr2–O5A
O3–Pr2–O5
149.67(18)
86.81(12)
137.96(10)
137.96(10)
139.90(11)
75.56(17)
78.53(10)
68.31(6)
[
2
(H
2
O)
5
]Clꢀ4H
2
O] (1)
99.19(17)
71.88(18)
80.12(19)
75.8
O3—H3BꢀꢀꢀN3#1
O3—H3CꢀꢀꢀO6
0.85
0.85
0.85
0.85
0.85
0.85
0.83
0.85
0.85
0.85
0.85
0.93
1.96
2.15
2.08
2.43
2.42
2.31
1.93
2.05
2.23
2.12
2.26
2.75
2.7735
2.8798
2.7767
3.2337
3.2206
3.1214
2.721(3)
2.8063
2.9913
2.9528
3.0426
3.606(9)
160
144
139
158
158
159
160
148
150
167
153
153
O4—H4AꢀꢀꢀN2#2
O4—H4BꢀꢀꢀN3#2
139.45(18)
70.86(6)
128.2
O4—H4BꢀꢀꢀCl1#3
O4—H4BꢀꢀꢀCl1#4
O5—H5BꢀꢀꢀO2#4
O6—H6BꢀꢀꢀO7
137.48(11)
96.73(12)
70.28(7)
84.12(7)
119.0
73.78(12)
144.29(6)
138.15(11)
69.47(9)
O6—H6CꢀꢀꢀO3#5
O7—H7BꢀꢀꢀN5#6
O7—H7CꢀꢀꢀN4#7
C3—H3AꢀꢀꢀCl1#4
76.05(7)
140.13(11)
72.84(9)
142.39(10)
76.28(7)
105.70(3)
141.50(8)
73.96(7)
[Pr
2
(tzpya)
2
(H
2
O)12]Cl
4
ꢀ2H
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
0.85
2
O (2)
O3—H3BꢀꢀꢀCl2#1
O3—H3CꢀꢀꢀN1#2
O3—H3CꢀꢀꢀN2#2
O6—H5CꢀꢀꢀCl3
2.47
1.88
2.62
2.24
2.62
2.01
2.23
2.11
2.50
1.91
2.30
2.29
3.0840
2.7150
3.3037
3.0841
3.4626
2.8314
3.0540
2.7431
3.2821
2.7502
3.1448
3.036(16)
130
167
138
172
170
163
165
130
153
168
170
146
[
Dy(pytza)
2
Cl(H
2
O)
2
]
n
(3)
2.3481(13)
O6—H6BꢀꢀꢀCl1#1
O7—H7BꢀꢀꢀO9
Dy1–O3
Dy1–O3A
2.3481(13)
2.355(2)
Dy1–O2B
Dy1–O1A
2.355(2)
2.3920(15)
70.03(7)
129.04(6)
72.22(6)
75.16(6)
77.00(3)
106.25(6)
144.98(3)
78.57(5)
93.44(5)
Dy1–O2C
O6—H6CꢀꢀꢀCl1#3
O7—H7CꢀꢀꢀN3#4
O8—H8AꢀꢀꢀN3#4
O8—H8AꢀꢀꢀN4#4
O8—H8BꢀꢀꢀCl1#1
O9—H9AꢀꢀꢀCl3#5
Dy1–O1
2.3920(15)
72.22(6)
O3–Dy1–O3A
O3A–Dy1–O2B
O3A–Dy1–O2C
O3A–Dy1–O1A
O3A–Dy1–O4
O2C–Dy1–O1
O3–Dy1–Cl1
O3–Dy1–O2C
O3–Dy1–O2C
O2B–Dy1–O2C
O3–Dy1–O1
O2B–Dy1–O1
O1A–Dy1–O1
O3A–Dy1–Cl1
O2C–Dy1–Cl1
O1–Dy1–Cl1
129.04(6)
157.15(11)
97.28(5)
75.16(6)
[Dy(pytza) Cl(H O) ] (3)
2
2
2
173.12(6)
144.98(3)
78.57(5)
O3—H3AꢀꢀꢀCl1#1
O3—H3BꢀꢀꢀN5#2
0.85
0.86
2.42
3.182
143
154
1.92(4)
2.7185
O2B–Dy1–Cl1
O1A–Dy1–Cl1
2 2 2
[Pr(pytza) Cl(H O) ] (4)
93.44(5)
O3—H3AꢀꢀꢀCl1#1
O3—H3BꢀꢀꢀN5#2
C8—H8ꢀꢀꢀO1#3
0.852(13)
0.85(2)
0.93
2.243(13)
1.90(2)
2.59
3.0948
177(18)
173(2)
142
2.741(3)
3.376(3)
[
Pr(pytza)
2
Cl(H
2
O)
2
]
n
(4)
Pr1–O3A
Pr1–O1
Pr1–O2
Pr1–Cl1
2.4543(15)
2.5159(17)
2.5172(16)
2.7766(2)
67.22(7)
Pr1–O3
2.4543(15)
2.5159(17)
2.5172(16)
2.8113(16)
76.42(6)
Symmetry codes.
Pr1–O1A
For 1 – #1: x, ꢁy, ꢁ0.5 þ z; #2: x, ꢁ1 þ y, z; #3: ꢁx, ꢁy, 1 ꢁ z; #4: x, 1 ꢁ y,
0.5 þ z; #5: 1.5 ꢁ x, 1 ꢁ y, 1 ꢁ z.
For 2 – #1: x, 1 ꢁ y, 0.5 þ z; #2: 1.5 ꢁ x, 0.5 ꢁ y, 1 ꢁ z; #3: 1 ꢁ x, y, 0.5 ꢁ z;
Pr1–O2B
ꢁ
Pr1–O2A
O3A–Pr1–O3
O3–Pr1–O1
O3A–Pr1–O3
O3A–Pr1–O1A
#
4: 1.5 ꢁ x, 1.5 ꢁ y, 1 ꢁ z, #5: 1 ꢁ x, 1 þ y, 0.5 ꢁ z.
92.54(5)
92.54(5)
For 3 – #1: 1 ꢁ x, 1 ꢁ y, ꢁz; #2: 0.5 þ x, 0.5 þ y, 0.5 þ z.
(
Continued)
For 4 – #1: 1 ꢁ x, ꢁy, ꢁz; #2: 0.5 þ x, 0.5ꢁ y, 0.5 þ z; #3: 0.5 ꢁ x, 0.5ꢁ y, ꢁz.

Htzpya- and Hpytza-Based Compounds
893
N5
(
O3–H3AꢀꢀꢀCl1), between the coordinated water and the nitro-
gen atom of the tetrazolyl ring (O3–H3BꢀꢀꢀN5, and between the
C–H group of the pyridyl and the oxygen atom of the
carboxylate group (C8–H8ꢀꢀꢀO1), generating a 3D network
N4
(Fig. S4, Supplementary Material; Table 3).
N3
N1
O1
Luminescence Properties
N2
The luminescence properties of 1–4 and the free ligands
were investigated at room temperature in the solid state. As is
shown in Fig. 8, the free ligands Htzpya and Kpytza (Kpytza¼
O1A
5
-(3-pyridyl)tetrazole-2-acetato potassium salt) exhibit maxi-
O2
O2A
mum emissions at 360 and 450 nm upon excitations at 315
and 347 nm, respectively. Compounds 1–4 exhibit photo-
luminescence with maximum intensities at 401, 392, 468, and
Cl1
O3
O3A
5
08 nm upon excitations at 270, 273, 373, and 371 nm, respec-
Dy1
O2B
O2C
tively. These fluorescence emissions could be tentatively
assigned to the intraligand fluorescence emissions. The red shift
in the maximum intensity may be ascribed to the coordination of
the ligand to the metal centre. Generally, the intraligand fluo-
rescence emission wavelength is determined by the energy gap
between the p and p* molecular orbitals of the free ligand, and
is related to the extent of p conjugation. In contrast with 1, a red
shift of 67 nm of the peak emission in 3 is found, and is slightly
smaller than the shift of the free ligands (90 nm). The difference
in maximum intensity of compounds 2 and 4 is 106 nm, dem-
onstrating that the group position difference really has an impact
on the luminescence.
O1B
O1C
O
Dy
Cl
N
C
III
Fig. 4. Coordination environment of Dy in compound 3. Hydrogen
atoms are omitted for clarity.
O5
O2
O3A
c
O3
O2A
a
N1
Dy1
O1
O4
O1A
O4A
Dy
O
N2
N3
N5
N4
O
N
Dy
Cl
N
C
C
III
Fig. 2. Coordination environment of Dy in compound 1. Hydrogen
atoms are omitted for clarity.
Fig. 5. 1D Chain structure of 3 extending along the c-axis.
O7
N4A
N1A
O7A
N4
N3A
N2A
O8
O8A
Pr1
N3
O6A
N5
N2
O6
O1
O2
O1A
N1
N5A
O2A
O4A
O4
Pr
O
N
O3A
Pr2
O3
O5A
C
O5
III
Fig. 3. Coordination mode of Pr in compound 2. Hydrogen atoms are omitted for clarity.

8
94
J. H. Zou et al.
N5
TGA
In terms of thermal stability, TGA of 1–4 was carried out in the
temperature range of 30–8008C under nitrogen atmosphere
(
Fig. 9). The TG curves show initial weight losses of 20.47 %
N4
from 30 to 2198C for 1, 27.22 % from 30 to 2578C for 2, 5.60 %
from 195 to 2598C for 3, and 5.65 % from 191 to 2338C for 4 that
can be ascribed to the loss of uncoordinated and coordinated
water molecules for compounds 1 and 2 (calculated as 20.18 %
for 1 and 27.27 % for 2) and the loss of coordinated water
molecules for compounds 3 and 4 (calculated as 5.52 % for 3 and
N1
N3
N2
O1C
5
2
.71 % for 4). Further weight losses beginning at 2198C for 1,
578C for 2, 2598C for 3, and 2338C for 4 are probably caused by
O1
O2C
O2
the decomposition of the tzpya ligands for 1 and 2 and the
decomposition of pytza ligands for 3 and 4, leading to the col-
lapse of the framework.
Cl1
O3
O3A
Pr1
Conclusions
III
To the best of our knowledge, we are the first to report Dy and
III
Pr coordination compounds with Htzpya and Hpytza. Four
O1B
O1A
new coordination compounds were successfully constructed.
The different positions of the carboxylate group control
the coordination modes of the ligands and further determine the
structure of the compounds. The luminescence properties show
the intraligand emissions. Our research results indicate that the
difference of the carboxylate group really has an impact on the
structure of the complexes and further endeavours for explora-
tion of other isomeric ligands are underway in our work group.
O
Pr
Cl
N
C
100
III
Fig. 6. Coordination mode of Pr in compound 4. Hydrogen atoms are
9
8
7
6
5
4
3
0
0
0
0
0
0
0
omitted for clarity.
3
b
4
c
1
a
2
O
Pr
Cl
N
200
400
600
800
1000
C
T [ЊC]
Fig. 7. 1D Chain structure of 4 extending along the c-axis.
Fig. 9. TG curves of compounds 1–4.
(
a) 7000
(b)
1
1
600
400
6000
5000
4000
3000
2000
1000
0
L2
1200
000
L1
1
8
6
4
2
00
00
00
00
0
3
2
4
1
300
350
400
450
500
350 400 450 500 550 600 650
Wavelength [nm]
Wavelength [nm]
Fig. 8. (a) Emission spectra of 1, 2, and ligand 1 (L1) at room temperature in the solid state. (b) Emission spectra of 3, 4, and ligand 2
L2) at room temperature in the solid state.
(

Htzpya- and Hpytza-Based Compounds
895
Supplementary Material
[6] (a) J. Fan, G. T. Yee, G. B. Wang, B. E. Hanson, Inorg. Chem. 2006, 45,
5
99. doi:10.1021/IC051286H
b) S. L. Li, Y. Q. Lan, J. F. Ma, J. Yang, G. H. Wei, L. P. Zhang, Z. M.
Su, Cryst. Growth Des. 2008, 8, 675. doi:10.1021/CG7009385
c) X. Zhu, P. P. Sun, J. G. Ding, B. L. Li, H. Y. Li, Cryst. Growth Des.
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The stacking pictures of compounds 1–4 are available on the
Journal’s website.
(
(
2
Acknowledgements
The authors appreciate financial support from the14th Challenge Cup for
Domestic College Students, College Students’ Innovation and Entre-
preneurship Training Program of Jiangsu Province, and the Start Grant from
CSLG.
[
7] (a) X. Y. Wang, H. Y. Wei, Z. M. Wang, Z. D. Chen, S. Gao, Inorg.
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