Two picolinamide-based Zn(II) coordination polymers: Syntheses, structures, and catalytic activities

Article abstract of DOI:10.1080/15533174.2011.609227

Two picolinamide-based zinc(II) coordination polymers {[Zn(SO ₄)(3-bpit) (CH₃OH)₂]·2CH ₃OH}_n (1)(3-bpit = N,N'-bis(3-pyridylformyl)imidazolidine- 2-thione) and [Zn(SCN)₂(4-bpit)]_n(2) (4-bpit = N,N'-bis(4-pyridylformyl)imidazolidine -2-thione) have been synthesized and structurally characterized. In complexes 1 and 2, the picolinamide-based ligands, 3-bpit and 4-bpit, function as bridging bidentate mode, leading to polymeric structures. Complex 1 is a two-dimensional coordination polymer while 2 exhibits a one-dimensional chain structure. The hydrolysis of 4-nitrophenyl acetate catalyzed by complexes 1 and 2 under mild conditions was also investigated.

Full text of DOI:10.1080/15533174.2011.609227

This article was downloaded by: [University of California Santa Cruz]
On: 26 October 2014, At: 09:55
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Synthesis and Reactivity in Inorganic, Metal-Organic,
and Nano-Metal Chemistry
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/lsrt20
Two Picolinamide-Based Zn(II) Coordination Polymers:
Syntheses, Structures, and Catalytic Activities
Linke Li a , Hongchang Yao a , Jingjing Zhao a , Zhihui Yang a & Hongwei Hou a
a Department of Chemistry , Zhengzhou University , Henan , P. R. China
Published online: 31 Jan 2012.
To cite this article: Linke Li , Hongchang Yao , Jingjing Zhao , Zhihui Yang & Hongwei Hou (2012) Two Picolinamide-Based
Zn(II) Coordination Polymers: Syntheses, Structures, and Catalytic Activities, Synthesis and Reactivity in Inorganic, Metal-
Organic, and Nano-Metal Chemistry, 42:1, 46-52, DOI: 10.1080/15533174.2011.609227
To link to this article: http://dx.doi.org/10.1080/15533174.2011.609227
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 42:46–52, 2012
Copyright ꢀ Taylor & Francis Group, LLC
C
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2011.609227
Two Picolinamide-Based Zn(II) Coordination Polymers:
Syntheses, Structures, and Catalytic Activities
Linke Li, Hongchang Yao, Jingjing Zhao, Zhihui Yang, and Hongwei Hou
Department of Chemistry, Zhengzhou University, Henan, P. R. China
organisms, zinc(II), can function as the active site of hydrolytic
enzymes, where it is ligated by hard donors (N– or O–). Mean-
while, it has long been recognized that zinc(II) acts as a signif-
icant co-factor in biological molecules, either as a structural
template in the biochemical field or as a Lewis acid cata-
Two picolinamide-based zinc(II) coordination polymers
{[Zn(SO4)(3-bpit) (CH3OH)2]·2CH3OH}n (1)(3-bpit = N,N’-bis(3-
pyridylformyl)imidazolidine-2-thione) and [Zn(SCN)2(4-bpit)]n
(2) (4-bpit = N,N’-bis(4-pyridylformyl)imidazolidine -2-thione)
have been synthesized and structurally characterized. In complexes
1 and 2, the picolinamide-based ligands, 3-bpit and 4-bpit, function
as bridging bidentate mode, leading to polymeric structures. Com-
plex 1 is a two-dimensional coordination polymer while 2 exhibits a
one-dimensional chain structure. The hydrolysis of 4-nitrophenyl
acetate catalyzed by complexes 1 and 2 under mild conditions was
also investigated.
lyst.[9–13] For example, Dołega et al.[10] investigated the zinc(II)
ꢀ
and cobalt(II) complexes with appropriate ligands (tri-tert-
butoxysilanethiol and 2-ethylimidazole) mimicking the active
site of alcohol dehydrogenase. Others, such as Mao et al.,[14]
also studied similar reactions, demonstrating the promotion ef-
fect of Zn-containing complexes in certain reactions.
Herein, we used two picolinamide-based ligands, 3-bpit
and 4-bpit (3-bpit = N,N’-bis(3-pyridylformyl)imidazolidine-
2-thione; 4-bpit = N,N’-bis(4-pyridylformyl) imidazolidine-
2-thione) (Scheme 1), to self-assemble with zinc(II) salts,
and obtained two coordination polymers {[Zn(SO4)(3-
bpit)(CH3OH)2]·2CH3OH}n (1) and [Zn(SCN)2(4-bpit)]n (2).
The hydrolysis of 4-nitrophenyl acetate (NA) catalyzed by 1 and
2 were studied and the results show that 1 and 2 can promote the
hydrolysis reactions and display effective catalytic activities.
Keywords catalytic activity, hydrolysis, picolinamide, polymers,
structure, zinc(II)
INTRODUCTION
Acylamide has often been used as excellent organic bridg-
ing ligand in the coordination chemistry for obtaining diverse
coordination polymers with various structures, and their com-
plexes are attractive due to the biological relevance of the
acylamide group in peptides and proteins,[1–8] therefore, using
acylamide as a bridging group to connect metal centers might
offer some fascinating properties for the obtainable complexes.
Moreover, acylamide is a kind of little stronger Lewis base
compared with some linkers such as carboxylate species.[1, 2]
Picolinamide-based ligands contain one or more acylamide
functional groups, and available N–/O– donors make this kind
of ligand exhibit multifarious coordination modes (monoden-
tate, bidentate, and chelate) in the self-assembly process. What
is more, their complexes often contain unpredictable patterns
of hydrogen bonding, which can add extra dimensionality and
helicity to the final molecular architectures. In the case of the
metal ion, as the second most abundant transition metal in living
EXPERIMENTAL
General Details
All chemicals were of reagent-grade quality obtained from
commercial sources and were used without further purifica-
tion. The ligands of N,N’-bis(3-pyridylformyl)imidazolidine-
2-thione (3-bpit) and N,N’-bis(4-pyridylformyl)imidazolidine-
2-thione (4-bpit) (Scheme 1) were prepared according to the
method in the reported articles.[15, 16]
C, H, and N analyses were carried out on a Carlo-Erba 1106
elemental analyzer. IR data were recorded on a BRUKER TEN-
SOR 27 spectrophotometer with KBr pellets in the 400–4000
cm−1 region. A PHs-25 pH meter was used for all pH measure-
ments. Kinetic measurements were made using the UV/vis-7200
spectrophotometer.
Received 29 May 2011; accepted 26 July 2011.
The authors gratefully acknowledge the financial support by the
National Natural Science Foundation of China (Nos. 20801048 and
20971110) and the Basic Research Program of Henan Province
(2008A150025).
Address correspondence to Linke Li, Department of Chemistry,
Zhengzhou University, Zhengzhou 450001, P. R. China. E-mail:
lilinke@zzu.edu.cn
Preparation of {[Zn(SO4)(3-bpit)(CH3OH)2]·2CH3OH}n
(1)
A 7 mL methanol solution of 3-bpit (62.4 mg, 0.200 mmol)
was dropwise added into an aqueous solution of ZnSO4·7H2O
(28.8 mg, 0.100 mmol, 1 mL). Pale yellow crystals suitable for
46

ZN(II) COORDINATION POLYMERS
47
O
O
O
O
N
N
N
N
S
S
N
N
N
N
4-bpit
3-bpit
SCH. 1.
was maintained at 0.1 mol·dm−3 NaCl. Experiments were car-
X-ray single-crystal analysis were obtained after three days at
room temperature. The crystals are unstable in the air. Yield:
71%. Anal. Calcd. for C18H22N4O9S2Zn(%): C, 38.04; H, 3.87;
N, 9.86. Found: C, 38.18; H, 3.65; N, 9.96. IR (cm−1, KBr):
3440 w, 3070 w, 1686 s, 1609 w, 1404 m, 1298 s, 1235 m,
1130 m, 877 w, 827 w, 746 w, 617 w.
ried out at least twice.
RESULTS AND DISCUSSION
Molecular Structure of
{[Zn(SO4)(3-bpit)(CH3OH)2]·2CH3OH}n (1)
Preparation of [Zn(SCN)2(4-bpit)]n (2)
The X-ray diffraction analysis of complex 1 shows that it
crystallizes in the monoclinic space group P21/c and displays a
two-dimensional network structure. As illustrated in Figure 1,
each Zn(II) in complex 1 is located in a slightly distorted octahe-
dral environment and is coordinated by two pyridine-N donors
A 2 mL DMF solution of 4-bpit (62.4 mg, 0.200 mmol)
was added to the 5 mL CH3OH solution of Zn(NO3)2·6H2O
(29.7 mg, 0.100 mmol) and KSCN (18.5 mg, 0.200 mmol), and
the resulting reaction mixture was stored at room temperature.
After one week, pale yellow crystals of X-ray quality were
obtained. The crystals are air-stable. Yield: 60%. Anal. Calcd.
for C17H10N6O2S3Zn(%): C, 41.47; H, 2.03; N, 17.08. Found:
C, 41.55; H, 2.15; N, 17.18. IR (cm−1, KBr): 3448 w, 3069 w,
2076 s, 1684 s, 1617 m, 1553 w, 1411 s, 1365 m, 1299 s, 1241 s,
1142 m, 838 s, 671 s.
TABLE 1
Crystal data and structure refinement for 1 and 2
1
2
Formula
Formula weight
Temperature [K]
Crystal system
Space group
Crystal dimensions
[mm3]
C18H22N4O9S2Zn C17H10N6O2S3Zn
X-Ray Crystallography
567.89
293(2)
Monoclinic
P2(1)/c
0.20 × 0.18 ×
0.16
491.91
293(2)
Triclinic
P-1
Crystal data collection and refinement parameters for 1 and 2
are given in Table 1. All measurements were made on a Rigaku
RAXIS-IV imaging plate area detector with graphite monochro-
mated Mo-Kα radiation (λ = 0.71073 Å). Single crystals of 1
and 2 were selected and mounted on glass fibers, respectively.
The data were collected at a temperature of 291(2) K and cor-
rected for Lorentz and polarization effects. A correction for
secondary extinction was applied. The structures were solved
by direct methods and expanded using Fourier techniques. The
non-hydrogen atoms were refined anisotropically. Hydrogen
atoms were included but not refined. The final cycle of full-
matrix least-squares refinement was based on observed reflec-
tions and variable parameters. All calculations were performed
using the SHELXL-97 crystallographic software package.[17] Se-
lected bond lengths and bond angles are tabulated in Table 2.
0.24 × 0.20 ×
0.18
a [Å]
b [Å]
11.168(2)
11.478(2)
22.484(5)
90
94.19(3)
90
6.8238(14)
12.069(2)
12.977(3)
92.40(3)
102.54(3)
91.67(3)
1041.5(4)
2
c [Å]
α [o]
β [o]
γ [o]
V [Å3]
2874.4(10)
4
Z
F(000)
1168
496
ρ [g cm−3
]
1.312
1.626
Kinetics of 4-Nitrophenyl Acetate Hydrolysis
µ [mm−1
]
1.046
1.512
The hydrolysis rate of 4-nitrophenyl acetate (NA) was mea-
sured by an initial slope method following the increase ab-
sorption of the released 4-nitrophenolate (NP) at 402 nm
Data/restrains/parameters 5049/1/331
4723/0/267
1.050
Goodness of fit on F2
R1 = [I > 2σ (I)]
wR2 (all data)
1.028
0.0562
0.1881
0.0530
0.1320
in 10% (v/v) CH3CN aqueous solution at 30.0
0.5◦C
on a Vis-7200 spectrophotometer. Buffered solutions contain-
ing 0.05 mol·dm−3 tris-(hydroxymethyl)-aminomethane (Tris)
buffer (pH 7–9) were used and the ionic strength of the buffer
ꢀ
ꢀ
aR = ||Fo|−|Fc||/ |Fo|
ꢀ
ꢀ
bRw = [ (||Fo|−|Fc||)2/ w|Fo|2]1/2
.

48
L. LI ET AL.
TABLE 2
Selected bond lengths (Å) and angles (◦) for 1 and 2
Complex 1
Zn(1)-O(3)
Zn(1)-O(8)
2.083(3)
2.228(4)
Zn(1)-O(5)#1
Zn(1)-O(7)
2.090(3)
2.293(3)
Zn(1)-N(1)#2
2.318(3)
Zn(1)-N(2)
2.182(4)
O(3)-Zn(1)-O(5)#1
O(3)-Zn(1)-N(2)
O(3)-Zn(1)-O(8)
N(2)-Zn(1)-O(8)
O(5)#1-Zn(1)-O(7)
O(3)-Zn(1)-N(1)#2
N(2)-Zn(1)-N(1)#2
O(7)-Zn(1)-N(1)#2
177.38(11)
92.57(12)
89.40(14)
176.22(14)
92.37(13)
91.84(12)
98.14(13)
173.39(13)
O(8)-Zn(1)-O(7)
O(5)#1-Zn(1)-N(2)
O(5)#1-Zn(1)-O(8)
O(3)-Zn(1)-O(7)
N(2)-Zn(1)-O(7)
O(5)#1-Zn(1)-N(1)#2
O(8)-Zn(1)-N(1)#2
88.44(16)
89.98(12)
88.02(14)
87.16(12)
88.43(14)
88.33(13)
85.02(14)
Complex 2
Zn(1)-N(1)
Zn(1)-N(3)
1.939(4)
2.041(3)
Zn(1)-N(2)
Zn(1)-N(6)#2
1.919(4)
2.044(3)
N(2)-Zn(1)-N(1)
N(1)-Zn(1)-N(3)
N(1)-Zn(1)-N(6)#2
118.05(19)
108.56(17))
107.46(16)
N(2)-Zn(1)-N(3)
N(2)-Zn(1)-N(6)#2
N(3)-Zn(1)-N(6)#2
111.33(16)
113.35(16)
95.73(12)
Symmetry transformations used to generate equivalent atoms; For 1: #1 −x+1,y−1/2,−z+3/2 #2 x−1, y, z #3 −x+1, y+1/2, −z+3/2 #4
x+1, y, z. For 2: #1 x,y+1,z #2 x,y−1,z.
from two ligands and four oxygen atoms from two methanol nects the central Zn(II) ions together, forming a one-dimensional
molecules and two SO24− ions, respectively. Two oxygen atoms zigzag chain structure, which is also different from the re-
(O3 and O5B) of two SO24− anions coordinating with the cen- ported polymer {[Co(SCN)2(4-bpit)2]·CH3OH·CH3CN}n with
tral Zn(II) atom form a O–Zn–O axis and the central Zn(II) with one-dimensional double-stranded chains.[16] Complex 2 crystal-
four atoms (N1, N2, O7, O8) constitute a equatorial plane (mean lizes in the space group P-1. Each Zn(II) atom is coordinated
deviation 0.0242 Å). The Zn–O distances are in the range of to two nitrogen atoms (N3 and N6A) from two different 4-
2.083(3)–2.293(3) Å, and the two Zn–N distances are 2.182(4) bpit ligands, and two nitrogen atoms (N1 and N2) from two
and 2.318(3) Å, respectively. The bond lengths are in agreement SCN− groups to form a slightly distorted tetrahedral environ-
with those observed in the reported Zn(II) complexes.[18–20] The ment as shown in Figure 2. The four Zn–N distances are not
bond angles around central Zn(II) vary from 88.40◦ to 177.44◦. equal. The Zn–N4-bpit distances, 2.041(3) Å and 2.044(3) Å, are
In the direction of the a-axis each 3-bpit acts as a bridging lig- slightly longer than the distances of Zn–NSCN−, 1.939(4) Å and
and to link two Zn(II) to form a one-dimensional infinite zigzag 1.919(4) Å. These are a little shorter than the Zn–N distances
chain with the N–Zn–N included angle of 98.13◦, and the adja- of complex 1 and are in the normal range of the reported Zn(II)
cent Zn···Zn distance along the chain is 11.168 Å. The adjacent polymers.[21] The included angle of N4-bpit–Zn–N4-bpit (95.73◦)
chains are bridged by SO42− anions to form a two-dimensional is slightly shorter than that of complex 1 (98.13◦), and this
latticed structure with the neighboring Zn···Zn distance of 5.994 may be mostly due to the difference of the dipyridyl ligands.
Å along the ac plane (Figure 1). The topological analyses per- The other N-Zn-N an◦gles of the [ZnN4] unit are in the range
formed by the OLEX program indicate that the network of 1 of 107.46◦ to 118.05 . The central Zn(II) ions are bridged by
could be classified as a (44 · 62) topological type if we defined the the 4-bpit forming a zigzag chain along the b-axis with Zn···Zn
central Zn(II) ions as nodes and simplified the 3-bpit ligands and distance of 12.069 Å, which is a little longer than that of com-
the SO24− anions as linkers. With the help of hydrogen bonding plex 1 (11.168 Å). Viewed along the c-axis, 2 is a layer struc-
interactions of oxygen atoms from SO42– ions and the dissocia- ture constructed by the weak interactions between Zn(II) ions
tive methanol solvent molecules, the two-dimensional networks and the acyl oxygen atoms from the adjacent chain (the Zn···O
are connected into a three-dimensional framework along the distance is 3.441 Å) (Figure 2). Furthermore, hydrogen bonds
−
c-direction.
of C–H···S4-bpit and weak interactions of S4-bpit···SSCN trans-
form the layer structure into a three-dimensional supramolecular
architecture.
Molecular Structure of [Zn(SCN)2(4-bpit)]n (2)
By comparing the structures of the two Zn(II) complexes,
it can be seen that the anion and the conformation of the lig-
and play important roles in the final structures of the complexes.
In complex 1 the 3-bpit and the sulfate function as bridg-
ing bidentate ligands resulting in a two-dimensional structure,
while in complex 2 only the 4-bpit functions as a bridge and con-

ZN(II) COORDINATION POLYMERS
49
FIG. 1. (a) The coordination environment of complex 1, all hydrogen atoms are omitted for clarity. (b) Crystal structure of 1 with 2-D network. The hydrogen
atoms are omitted for clarity.
This kind of phenomenon has been widely described in the liter-
atures.[22–24] In complex 1, the dipyridyl ligands 3-bpit connect
the adjacent Zn(II) together, and SO24− anions simultaneously act
as bridge to link the center Zn(II) ions to form a two-dimensional
latticed structure. However, the SCN− cannot play the role of
bridge as we expected in complex 2, where only the bridging
bidentate 4-bpit ligand links the Zn(II) to exhibit a 1-D zigzag
chain structure. The similar examples can also be observed in
the literatures.[23, 24]
4-Nitrophenyl Acetate (NA) Hydrolysis Promoted by
Complexes 1 and 2
Usually the Zn(II)-bound alkoxides or hydroxides, derived
from the deprotonation of the Zn(II)-bound external water or in-
ternal alcoholic residues in Zn(II)-containing enzymes, in some
cases can act as nucleophiles to attack electrophilic substrates
in the hydrolytic process.[13, 25–27] Now we use the carboxylester
NA as a substrate to further understand the reaction mech-
anism. We followed the hydrolysis of NA promoted by the

50
L. LI ET AL.
FIG. 2. 1-D chain of complex 2, all hydrogen atoms are omitted for clarity.
complexes 1 and 2 at different pH values in 10% (v/v) CH3CN of the blank experiment. It could be interpreted in terms of the
aqueous solution at 30◦C, by the release of 4-nitrophenolate generation of the nucleophilic LZn-OH species, which has been
(NP) at 402 nm. An initial slope method has been applied on shown to be the active species in previous works with related
the data processing procedure, as previously described in the ligands.[28, 29] The relationship between the hydrolysis rate and
literature.[25]
complex concentrations was also surveyed. At given pH values,
The results showed that 1 and 2 were both effective catalysts. the rates versus concentrations of complex 1 depicted the lin-
The linear dependence of the reaction rate–substrate concentra- ear dependence (Figure 4), while for 2 it indicated a saturation
tion plots are shown in Figure 3 at pH 8.00. As can be seen from behavior when the complex concentrations reached a certain
the data, the hydrolysis rate increased with substrate concen- value (Figure 5). The disparity may be ascribed to the structural
tration, and the rates of 1 and 2 were twofold higher than that differences between 1 and 2. Moreover, the rate rises with the
increasing of pH value. The main reason may be due to the fact
that the nucleophilic LZn-OH species increase with the grow-
ing numbers of OH−. As considered, the nucleophile LZn-OH
FIG. 3. Dependence of the reaction rate on the substrate concentrations for
the hydrolysis reaction promoted by 1, 2, and Zn(II) salt. Conditions: [NA] = FIG. 4. Dependence of the reaction rate on the concentrations of 1 for the
0.33 × 10−3 mol·dm−3—1.67 × 10−3 mol·dm−3; [complex]/Zn(II) salt = 6 × hydrolysis of NA. Conditions: [complex] = 0.2 × 10−3 mol·dm−3—1.0 ×10−3
10−4 mol·dm−3; buffer Tris (pH = 8.00); I = 0.1 mol·dm−3 (NaCl); T = 30◦C,
mol·dm−3; [substrate] = 0.5 ×10−3 mol·dm−3; I = 0.1 mol·dm−3 (NaCl); T =
in 10% (v/v) CH3CN aqueous solution.
30◦C, in 10% (v/v) CH3CN aqueous solution.

ZN(II) COORDINATION POLYMERS
51
data measured are very close. It can be seen from Figure 3 that
the hydrolysis processes catalyzed by the title complexes dis-
play slightly better effect than that of the Zn(II) salt. The results
demonstrate the efficiency of the two Zn(II) picolinamide-based
complexes as catalysis for this hydrolysis reaction. We hope this
work can provide some evidence for a better understanding of
the exact reaction mechanism catalyzed by this kind of complex
and the further research on the structure–property relationships
of these complexes is still ongoing.
SUPPLEMENTARY MATERIALS
Crystallographic data for the structures reported in this ar-
ticle have been deposited at the Cambridge Crystallographic
Data Centre as supplementary publication: CCDC-751839 and
751840 for 1 and 2, respectively. These data can be ob-
tained free of charge from CCDC, 12 Union Road, Cam-
bridge, CB2 1EZ, UK; Fax: +44(0)1223–33 6033; Email: de-
posit@ccdc.cam.ac.uk.
FIG. 5. Dependence of the reaction rate on the concentrations of 2 for the
hydrolysis of NA. Conditions: [complex] = 0.2 ×10−3 mol·dm−3—1.0 ×10−3
mol·dm−3; [substrate] = 0.5 ×10−3 mol·dm−3; I = 0.1 mol·dm−3 (NaCl); T =
30◦C, in 10% (v/v) CH3CN aqueous solution.
REFERENCES
attack the electrophilic center of NA, and in the meantime one
of the hydrogen atoms of water molecular bound to Zn(II) acts
on a receptor for the leaving groups. Then, the LZn-OH acts as
a nucleophile to attack the “acyl intermediate” to reproduce the
active species to recycle the hydrolysis process (Scheme 2).[25]
From the thermodynamics theoretical calculation (Equations 1
and 2),
1. Gong, Y.; Liu, J.Z.; Tang, W.; Hu, C.W. The intra-annular acylamide chelate-
coordinated compound: The keto-tautomer of metal (II)–milrinone com-
plex. J. Mol. Struct. 2008, 875, 113–120.
2. Cotton, F.A.; Liu, C.Y.; Murillo, C.A.; Wang, X.P. Dimolybdenum-
containing molecular triangles and squares with diamidate linkers: struc-
tural diversity and complexity. Inorg. Chem. 2006, 45, 2619–2626.
3. Bhogala, B.R.; Thallapally, P.K.; Nangia, A. 1:2 and 1:1 Ag(I)-
isonicotinamide coordination compounds: five-fold interpenetrated CdSO4
network and the first example of (pyridine)N–Ag–O(amide) bonds. Cryst.
Growth Des. 2004, 4, 215–218.
4. Girma, K.B.; Lorenz, V.; Blaurock, S.; Edelmann, F.T. Coordination chem-
istry of acrylamide. Coord. Chem. Rev. 2005, 249, 1283–1293.
5. Montenegro, M.; Moral-Naranjo, M.; Delgado, E.; Campoy, F.; Vi-
dal, C. Hydrolysis of acetylthiocoline, o-nitroacetanilide and o-
nitrotrifluoroacetanilide by fetal bovine serum acetylcholinesterase. FEBS
J. 2009, 276, 2074–2083.
ln(A∞ − At) − ln(A∞ − A0) = −kobs
t
[1]
[2]
kobs = Ae−Ea/RT
the activation energy (Ea) of 1 was higher than that of 2 (30.8
kJ·mol−1 for 1, 27.9 kJ·mol−1 for 2), thus the reaction rate of 1
was lower than that of 2. These were consistent with the kinetic
plots mentioned previously.
6. Clement, O.; Rapko, B.M.; Hay, B.P. Structural aspects of metal–amide
complexes. Coord. Chem. Rev. 1998, 170, 203–243.
7. Angus, P.M.; Fairlie, D.P.; Jackson, W.G. Synthesis, solution structure, and
reactivity of oxygen-bound amides on cobalt(III). Inorg. Chem. 1993, 32,
450–459.
8. Sigei, H.; Marthin, R.B. Coordinating properties of the amide bond. Sta-
bility and structure of metal ion complexes of peptides and related ligands.
Chem. Rev. 1982, 82, 385–426.
9. Auld, D.S. Zinc coordination sphere in biochemical zinc sites. Biometals
2001, 14, 271–313.
10. Dołega, A.; Pladzyk, A.; Baranowska, K.; Wieczerzak, M. Self-assembly of
ꢀ
zinc and cobalt complexes mimicking active site of alcohol dehydrogenase.
Inorg. Chem. Commun. 2008, 11, 847–850.
11. Sun, X.X.; Qi, C.M.; Ma, S.L.; Huang, H.B.; Zhu, W.X.; Liu, Y.C. Syntheses
and structures of two Zn(II) complexes with the pentadentate Schiff-base
ligands. Inorg. Chem. Commun. 2006, 9, 911–914.
12. Lipscomb, W.N.; Stra¨ter, N. Recent advances in zinc enzymology. Chem.
Rev. 1996, 96, 2375–2434.
13. Vallee, B.L.; Auld, D.S. Zinc: biological functions and coordination motifs.
Acc. Chem, Res. 1993, 26, 543–551.
14. Zhou, Y.-H.; Fu, H.; Zhao, W.-X.; Tong, M.-L.; Su, C.-Y.; Sun, H.Z.; Ji, L.-
N.; Mao, Z.-W. An effective metallohydrolase model with supramolecular
environment: structures, properties and activities. Chem. Eur. J. 2007, 13,
2402–2409.
SCH. 2. The reaction mechanism of the NA hydrolysis.
As a contrast, three complexes containing Co(II) and
Hg(II)[15, 16] as well as the free ligands 3-bpit/4-bpit were used as
catalysts in the hydrolysis reaction, but they were all ineffective.
The corresponding Zn(II) salts, namely, ZnSO4 and Zn(SCN)2,
were also investigated as catalysts in this reaction for comparing.
The results show that the Zn(II) salts with the different anions do
not have obviously distinction in the catalytic reaction, and the

52
L. LI ET AL.
15. Li, L.K.; Song, Y.L.; Hou, H.W.; Liu, Z.S.; Fan, Y.T.; Zhu, Y. Self-assembly
of HgI2 with linear and angular bipyridine ligands: mercury(II) polymer and
metallamacrocycle. Inorg. Chim. Acta. 2005, 358, 3259–3266.
16. Li, L.K.; Yang, H.Y.; Song, Y.L.; Hou, H.W.; Fan, Y.T. Two cobalt(II) one-
dimensional a ribbon of rings polymers: syntheses, structures and non-linear
optical properties. Inorg. Chim. Acta. 2006, 359, 2135–2140.
17. Sheldrick, G.M. SHELXL-97, Program for the Solution and Refinement of
Crystal Structures. University of Go¨ttingen, Germany, 1997.
18. Meng, X.R.; Zhu, X.Q.; Qi, Y.F.; Hou, H.W.; Fan, Y.T. Syntheses, struc-
23. Du, M.; Guo, Y.M.; Chen, S.T.; Bu, X.H.; Batten, S.R.; Ribas, J.;
Kitagawa, S. Preparation of acentric porous coordination frameworks
from an interpenetrated diamondoid array through anion-exchange pro-
cedures: crystal structures and properties. Inorg. Chem. 2004, 43, 1287–
1293.
24. Huang, Z.; Song, H.B.; Du, M.; Chen, S.T.; Bu, X.H.; Ribas, J. Coor-
dination polymers assembled from angular dipyridyl ligands and CuII,
CdII, CoII salts: crystal structures and properties. Inorg. Chem. 2004, 43,
931–944.
tures and thermal stabilities of eight 1-((benzotriazol-yl)methyl)-1H-1,3- 25. Huang, J.; Li, D.F.; Li, S.A.; Yang, D.X.; Sun, W.Y.; Tang, W.X. Kinetic
imidazole complexes based on different anions. J. Mol. Struct. 2009, 934,
28–35.
analysis of carboxy ester hydrolysis by a dinuclear Zn(II) complex. J. Inorg.
Biochem. 2004, 98, 502–509.
19. Wu, J.; Pan, F.F.; Hou, H.W.; Zhao, J.A.; Zhao, Y.F.; Fan, Y.T. Design and
construction of two new polymers featuring macrocyclic subunits based on
a rigid clamp-like ligand. Inorg. Chem. Commun. 2009, 12, 750–754.
20. Song, J.H.; Li, X.; Zou, Y.Q. Supramolecular structures assembled based
on mononuclear 2,6-naphthalenedisulfonate zinc(II) complexes. J. Coord.
Chem. 2010, 63, 223–233.
21. Meng, X.R.; Song, Y.L.; Hou, H.W.; Fan, Y.T.; Li, G.; Zhu, Y. Novel Pb and
Zn coordination polymers: synthesis, molecular structures, and third-order
nonlinear optical properties. Inorg. Chem. 2003, 42, 1306–1315.
22. Du, M.; Bu, X.H.; Guo, Y.M.; Liu, H.; Batten, S.R.; Ribas, J.; Mak, T.C.W.
First CuII diamondoid net with 2-fold interpenetrating frameworks. The role
of anions in the construction of the supramolecular arrays. Inorg. Chem.
2002, 41, 4904–4908.
26. Lipscomb, W.A.; Strater, N. Recent advances in zinc enzymology. Chem.
Rev. 1996, 96, 2375–2434.
27. Xu, X.; Lajmi, A.R.; Canary, J.W. Acetaldehyde hydration by zinc–hydroxo
complexes: coordination number expansion during catalysis. Chem. Com-
mun. 1998, 2701–2702.
28. Costas, M.; Anda, C.; Llobet, A.; Parella, T.; Evans, H.S.; Pinilla, E. Syn-
thesis, structure and hydrolitic properties of a family of new Zn com-
plexes containing hexaazamacrocyclic ligands. Eur. J. Inorg. Chem. 2004,
4, 857–865.
29. Bencini, A.; Berni, E.; Bianchi, A.; Fusi, V.; Giorgi, C.; Paoletti, P.; Valtan-
coli, B. Carboxy and diphosphate ester hydrolysis promoted by dinuclear
zinc(II) macrocyclic complexes. Role of Zn(II)-bound hydroxide as the
nucleophilic function. Inorg. Chem. 1999, 38, 6323–6325.