Synthesis, Crystal Structure, and Catalytic Properties of Porous 3d-4f Heterometallic Coordination Polymers Constructed from Pyrazine-2,3-dicarboxylic Acid

Article abstract of DOI:10.1002/zaac.201700344

Reactions of pyrazine-2,3-dicarboxylic acid (H₂pzdc), cobalt nitrate and lanthanide (Ln) oxide under hydrothermal conditions result in four new 3d-4f heterometal coordination polymers, namely, [Ln₂Co(pzdc)₄(H₂O)

Full text of DOI:10.1002/zaac.201700344

Title: Synthesis, Crystal Structure and Catalytic Property of Porous
d-4f Heterometallic Coordination Polymers Constructed from
3
Pyrazine-2,3-dicarboxylic Acid
Authors: Ting-Hai Yang, Ana Rosa Silva, Lianshe Fu, and Fa-Nian Shi
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To be cited as: Z. anorg. allg. Chem. 10.1002/zaac.201700344
Link to VoR: http://dx.doi.org/10.1002/zaac.201700344

Zeitschrift für anorganische und allgemeine Chemie
10.1002/zaac.201700344
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Synthesis, Crystal Structure and Catalytic Property of Porous 3d-4f
Heterometallic Coordination Polymers Constructed from Pyrazine-2,3-
dicarboxylic Acid
[a,b]
[b]
[d]
[c]
Ting-Hai Yang,* Ana Rosa Silva, Lianshe Fu, and Fa-Nian Shi*
Abstract: Reactions of pyrazine-2,3-dicarboxylic acid (H
nitrate and lanthanide (Ln) oxide under hydrothermal conditions result in
four new 3d-4f heterometal coordination polymers, namely,
Ln Co(pzdc) (H O) ]·2H O {Ln = La (1), Pr (2), Eu (3) and Gd (4)}. All
2
pzdc), cobalt
to use N/O mixed ligands for preparation of TMLnCPs. The f-block Ln
ions act as hard acids and prefer O-donors to N-donors, while d-block
metal ions have a strong tendency to react to both N- and O-donors.[2g]
Therefore, an effective strategy to synthesize TMLnCPs is the use of
multiple coordination sites with bifunctional or multifunctional ligands,
such as amino acids,[7] imidazoledicarboxylic acid[8] and
pyridinecarboxylic acid[9] that can hold the TM and Ln at the same
[
2
4
2
6
2
compounds were characterized by elemental analysis, infrared spectroscopy,
thermal gravimetric analysis and X-ray diffraction. The compounds exhibit
a three dimensional (3-D) brick-like structure with rectangular-shaped
nano-scale channels along a-axis direction, made up of wave-like layers
2
time. Pyrazine-2,3-dicarboxylic acid (H pzdc) is one of the excellent
+
containing [Ln(pzdc)] unit which are connected by one dimensional (1-D)
N/O mixed ligands for construction of TMLnCPs due to its
coordination behaviours that serve as a bridge linker between Ln and
TM ions. However, to the best of our knowledge, only a limited
2-
2
chain of [Co(pzdc) ] . The catalytic properties of compounds 1 and 3 were
investigated in the synthesis of cyanohydrins at room temperature under
solventless conditions. They showed similar catalytic activities with very
high conversions of benzaldehyde and high selectivity towards the
cyanohydrin. The control experiment without addition of the coordination
polymers only reached 16% conversion. Other aldehydes could also be
converted totally under shorter reaction times also with very high
selectivities for the corresponding cyanohydrins. Compound 1 could also be
recycled in another catalytic cycle.
number of 3d–4f coordination polymers[10] based on H
2
pzdc have been
reported.
On the other hand, porous coordination polymers have attracted
great interest for their potential in adsorption and catalysis due to their
high surface areas with well-defined pore properties, easily tunable and
tailorable structures and chemical functionality, which facilitate
diffusion and the interfacial contact between the active site and the
reagents.[11] Recently, we have reported that a series of novel porous
TMLnCPs[5b–5d] based on some N/O mixed ligands were active and
recyclable heterogeneous catalysts. Four 2-D porous Ln-Co 3d-4f
TMLnCPs were synthesized hydrothermally through self-assembling
pyridine-2,3-dicarboxylic acid ligand, cobalt and Ln ions, which were
active in cyanohydrins reaction.[5c] Furthermore, the structure of
2
Introduction
In recent years, the design and construction of transition metal–
lanthanide (3d-4f) heterometallic coordination polymers (TMLnCP) are
one of the most stimulating research frontiers in materials chemistry.[1]
The considerable interest in this field is driven by two major reasons:
first, the incorporation of a second metal centre may allow the
construction of novel beautiful architectures and topology structures,
and second, the introduction of unusual metal coordination
environments may influence the physical properties of the materials,
especially their magnetism,[2] luminescence,[3] adsorption[4] and
catalysis.[5] However, it is difficult to prepare novel 3d-4f TMLnCPs
due to the fact that the competing reaction between transition metal
H pzdc ligand is similar to that of the pyridine-2,3-dicarboxylic acid.
Inspired by these results, we wondered whether it is feasible to use
2
other N/O mixed linkers H pzdc and cobalt ion to construct porous 3d–
4f TMLnCPs with novel functional materials. As a result, we used a
one-pot reaction to assemble four new 3d-4f TMLnCPs,
[Ln Co(pzdc) (H O) ]·2H O {Ln = La (1), Pr (2), Eu (3) and Gd (4)},
2
4
2
6
2
based on this ligand, which exhibit a 3-D brick-like structure with
rectangular-shaped nano-scale channels along a-axis. In addition, the
catalytic properties of compounds 1 and 3 were also investigated.
(
TM) and lanthanide (Ln) coordinates to the same ligand. These
complicated competing coordination reactions often result in the
generation of preferably homometallic complexes instead of
heterometallic ones.[5b,6]
On the basis of the hard-and-soft-acid-base theory, it seems possible
Scheme 1 Synthesis of the 3d-4f heterometal coordination polymers.
Results and Discussion
[
a] School of Chemistry & Environmental Engineering, Jiangsu University
of Technology, Changzhou 213001, P. R. China
E-mail: tinghai_yang@hotmail.com
Synthesis and IR Spectra
[
[
b] Department of Chemistry, CICECO-Aveiro Institute of materials,
University of Aveiro, 3810-193 Aveiro, Portugal
c] School of Science, Shenyang University of Technology, Shenyang
Compounds 1–4 were synthesized hydrothermally under similar
2
conditions using Ln oxides, cobalt nitrate and H pzdc ( scheme 1). We
110870, P. R. China
E-mail: fshi96@foxmail.com
Department of Physics, CICECO-Aveiro Institute of materials,
University of Aveiro, 3810-193 Aveiro, Portugal
can get the products through one-pot with high yields although Wei et
al[10d] reported the similar structure Ce-Co compound through two steps
[
d]
reactions with about 6% total yield. The yields of those reactions
decreased gradually from 1 to 4. The results may imply that there
exists a competitive reaction in the crystal growth process of this
Supporting information for this article is available on the WWW under
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FULL PAPER
system and the decrease of Ln ion radius is not advantage to the
formation of 3d-4f coordination polymers. For terbium and lutetium
pure compounds could not be prepared.
oxygen atoms [O(8), O(8A), O(6B), O(6C)] and two pyrazine nitrogen
atoms [N(4), N(4A)] from four equivalent pydc2- ligands. The Co–O
and Co–N bond lengths are 2.072(3) Å, 2.147(3) Å and 2.092(4) Å,
respectively (Table 1). The La atom is nine-coordinated. Around the
La(1) atom, six positions are occupied by two pyrazine nitrogen atoms
[N(1), N(2D)] and four carboxylate oxygen atoms [O(1), O(5), O(4D),
O(3E)] from four equivalent pzdc2- ligands, and the remaining three
sites are occupied with three water molecules [O(9), O(10), O(11)].
The La–O lengths fall in the range of 2.450(3) and 2.600(4) Å with
slightly longer La–O(10) bond [2.600(4) Å], which are comparable to
those of reported Co-La compounds.[12]
The IR spectra for compounds 1−4 are similar (Figs. S1-S4). The
presence of lattice and coordination water molecules is manifested by a
-1
broad IR band of medium intensity in the range of about 3300 cm ,
assigned to ν(OH). No strong absorption peaks ranging from 1690 to
-1
1
730 cm for –COOH are observed in compounds 1–4, confirming that
all carboxyl groups of H pzdc ligand are deprotonated, which agrees
with the single X-ray crystal structure analysis. The strong peaks at
670–1350 cm-1 are assigned to the asymmetric and symmetric
2
1
vibrations of the coordinated carboxylate groups.
Ln
Co
O
O
Table 1 Selected bond lengths (Å) for 1-4.
1
(La)
2(Pr)
3(Eu)
4(Gd)
N
N
N
N
Co(1)-O(6)
Co(1)-O(8)
Co(1)-N(4)
Ln(1)-O(1)
Ln(1)-O(3E)
Ln(1)-O(4D)
Ln(1)-O(5)
Ln(1)-O(9)
Ln(1)-O(10)
Ln(1)-O(11)
Ln(1)-N(1)
Ln(1)-N(2D)
2.147(3)
2.072(3)
2.092(4)
2.450(3)
2.555(3)
2.504(3)
2.450(3)
2.517(3)
2.600(4)
2.528(3)
2.844(3)
2.818(4)
2.150(2)
2.081(2)
2.090(2)
2.401(2)
2.525(2)
2.464(2)
2.406(2)
2.469(2)
2.590(2)
2.489(2)
2.829(2)
2.784(2)
2.154(3)
2.080(3)
2.078(3)
2.364(3)
2.483(3)
2.424(3)
2.363(3)
2.418(3)
2.564(3)
2.437(3)
2.817(3)
2.753(3)
2.164(3)
2.082(3)
2.084(4)
2.347(3)
2.467(3)
2.399(3)
2.343(3)
2.398(3)
2.553(3)
2.415(3)
2.812(4)
2.731(4)
O
O
O
O
Ln
Ln
O
O
Ln
Co
(a)
(b)
Scheme 2 Coordination modes of pzdc2- ligand.
Symmetry codes: A: -x+1, -y, -z+1; B: -x+2, -y, -z+1; C: x-1, y, z; D: x+1/2, -y+1/2,
z-1/2 ; E: x-1/2, -y+1/2, z-1/2; F: x-1/2, -y+1/2, z+1/2, G: x+1/2, -y+1/2, z+1/2, H:
x+1, y, z.
Fig. 1 Building unit of 1 with the atomic labeling scheme (50% probability). All H
atoms and lattice water molecules were omitted for clarity. Symmetry codes are the
same as those given in Table 1.
+
Fig. 2 (a) Inorganic zigzag chain structure based on [La(pzdc)] unit in 1; (b) Inorganic
layer structure containing [La(pzdc)]+ unit in 1; (c) Inorganic chain structure of
[
Co(pzdc)
2
]2- in 1. All H atoms and water molecules were omitted for clarity.
Description of Structures
The pydc2- ligand adopts two coordination modes (Scheme 2) in
Compounds 1–4 are isostructural, crystallize in monoclinic lattice
compound 1, which is the same as the reported Ln-Zn compound.[10a]
with P2
1
/n space group. Hence only the structure of 1 will be discussed
One of the pzdc2− ligands coordinates metal centers in the coordination
in detail as representative. The asymmetric unit of 1 consists of one La
atom, one-half Co atom, two pzdc2- ligands, three coordinated water
and one lattice water molecules. As shown in Fig. 1, the Co atom has a
distorted octahedral environment, surrounded by four carboxylate
mode a where the pzdc2− ligand acts in a μ
2
2
1
5
-η N,O, η N′,O′, η O″
fashion, chelating two La atoms and bridging the third La atom,
respectively. The other pzdc2− ligand bonds metal atoms in mode b, in
which the pzdc2− ligand binds in a μ
2
1
1
4
-η N,O, η ,O′, η O″ fashion,
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chelating one Co atom and bridging one Co atom and one La atom,
respectively. The carboxylate group and the pyrazine ring of the pzdc2-
ligand are not coplanar. In mode a (Fig. S5), the dihedral angles
between pyrazine ring plane and the carboxylate plane containing O1
and O2, and the carboxylate plane containing O3 and O4 is 20.6° and
ligands. All topological studies were performed with the software
package TOPOS[13] and only the covalent bonds in the structure were
considered. In the compound 1, each crystallographically independent
metal center is taken as a node, with intermetal bridges ensured by the
bridging ligand. There are two types of coordination mode ligand as
above mentioned in compound 1. One links three La atoms while the
4
4.4°, respectively. In mode b (Fig. S6), the dihedral angles between
pyrazine ring plane and the carboxylate plane containing O(5) and O(6), other bonds two Co atoms and one La atom. So they are both viewed
and the carboxylate plane containing O(7) and O(8) is 82.1° and 12.5°,
respectively. The N(3) atom of pzdc2- ligand was not coordinated to
any metal ion.
as 3-connected nodes. Each La atom is connected to four pzdc2- ligands,
and is viewed as a 4-connected node. The Co atom is the same as La
atom. Thus, the final structures of 1 can be described as a 4-nodal
3,3,4,4-connected 3-D network with a point group symbol of
The La(1) and symmetric La(1) atoms are alternatively bridged by
the pzdc2- ligands in coordination mode a to form an infinite 1-D
{4·62}
2
2
2
3
5
2 2 2
{4 ·6 ·8 }{6 } {6 ·8} (Fig. S8).
+
zigzag chain of [La(pzdc)] unit along c-axis (Fig. 2(a)), in which the
distances between symmetric La(1) atoms are 8.3458(4) Å for
La(1)…La(1D). The chains are connected into an infinite 2-D layer
containing [La(pzdc)]+ unit in the ac plane through the carboxylate
oxygen atom [O(4)] of pzdc2- ligand (Fig. 2(b)). The La…La distances
across the O-C-O bridges are 6.1931(4) Å for La(1)…La(1B).
Meanwhile, two pzdc2- ligands connect two Co atoms in coordination
mode b into 1-D chain of [Co(pzdc)
between symmetric Co(1) atoms are 6.1931(2) Å for Co(1)…Co(1B)
Fig. 2(c)). The 2-D wave-layers in ac plane above mentioned were
2
]2- along a-axis. The distances
(
linked by the 1-D chains along a-axis constructed from Co atoms and
pzdc2- ligands through O5 and symmetric O5 atoms (Fig. 3). The
La…Co distances across the O-C-O bridges are 6.7563(3) Å.
Consequently, a 3-D metal organic frameworks (MOFs) structure with
pores was constructed (Fig. S7), in which there exist rectangular-
shaped nano-scale channels with size of 20.2 × 8.3 Å (the distances
between the metal centers) along a-axis direction. Lattice water
molecules reside in the pores as guests with hydrogen bonding
interaction with the oxygen atoms from the carboxyl and the
coordinated water molecules (Table S1). If the metal centre is taken as
a node, each La atom is further surrounded by four other La atoms and
one Co atom, while each Co atom is connected by two La atoms and
two La atoms via the bridging the pzdc2- ligands or its carboxyl group.
The framework structure of 1 may be simplified as a 3-D brick-like
structure (Fig. 4).
Fig. 4 Simplified inorganic framework structure of 1 with all C, N, O and H atoms
omitted. Green ball: Ln atom; pink ball: cobalt atom.
The structures of compounds 2–4 are analogous to 1 except that the
La atom in 1 is replaced by Pr in 2, Eu in 3 and Gd in 4. The cell
volumes decrease from 1 to 4, in accordance with the decreasing
sequence of the ionic radii of the corresponding metal ions due to the
Ln contraction.
SEM, EDS and PXRD
Fig. 3 Ball-and-stick representation displaying the porous network of 1 with the water
guests inside.
Fig. 5 SEM images of (a) 1, (b) 2, (c) 3 and (d) 4.
To further understand the topological structure of these compounds,
we examined the connection mode of the metal centers and organic
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SEM (Fig. 5) shows particles with almost similar crystal habits for
all compounds. EDS analyses (Figs. S9–S12) give molar ratios of
Co:La = 1:2 for 1, Co:Pr = 1:2 for 2, Co:Eu = 1:2 for 3 and Co:Gd =
using just 30 mg of coordination polymer (2.6% mol relatively to the
aldehyde). The blank experiment performed without addition of
catalyst proceeded with very low benzaldehyde conversion during the
48 h (maximum 16%, Fig. 8 and Table 2). Trimethylsilyl benzoate was
obtained as minor by-product. The scope of the reaction was extended
to another aromatic aldehyde (p-tolualdehyde) and an aliphatic
aldehyde (heptaldehyde) using coordination polymer (CP) 1. As
reported earlier,[15] the reactions proceeded much faster than using
benzaldehyde (Table 2). p-Tolualdehyde could be converted totally
within just 3 h of reaction with 99% of selectivity for the cyanohydrin
and TON of 36. Heptaldehyde was converted in 99% into the
heptaldehyde cyanohydrin with 98% selectivity within 21 h and TON
of 36, as well. As minor products the trimethylsilyl esters of the p-
tolualdehyde and heptaldehyde acids could be confirmed by GC-MS.
1
:2 for 4, which is in good agreement with the molecular formulae
derived from the single crystal structures.
The experimental and simulated PXRD patterns of complexes 1–4
are shown in Fig. 6. The experimental PXRD patterns at room
temperature are in good agreement with the simulated one based
single-crystal X-ray solution, indicating the phase purity of the bulk
products. The differences in reflection intensities are probably due to
the preferred orientation effects.
4
3
2
1
00
9
8
7
6
5
0
0
0
0
0
no catalyst
1
3
1
40
3
2
0
0
1
-simulated
50
10
0
0
5
10
15
20
25
30
35
40
45
50
t (h)
10
20
30
40

2
Fig. 8 Benzaldehyde conversion with time in the synthesis of cyanohydrin with
TMSCN at room temperature under solventless conditions using compounds 1 and 3
and control experiment without the use of catalyst.
Fig. 6 Experimental and simulated PXRD patterns of 1–4.
Catalytic property
Si(CH3)3
CN
O
O
Table 2 Catalytic application of CP 1 and 3 in the cyanosilylation of aldehydes.
Catalyst
+
(CH ) SiCN
RCOHa
%Cb
%Sc
TONd
TOF (h-1)e
3
3
Catalyst
none
Time (h)
r.t.
R
H
Ph
Ph
Ph
Ph
Ph
Phf
48
24
24
24
48
48
3
16
100
92
85
98
98
96
98
96
99
98
98
R
La
2
O
3
3
16
15
22
34
43
36
36
34
0.7
0.6
0.9
0.7
0.9
12.0
1.7
0.7
R = Ph, p-CH Ph, n-C H
3
6
13
Eu
2
O
CoNO
3
70
Fig. 7 Synthesis of cyanohydrins at room temperature.
1
94
MOFs and coordination polymers contain isolated potentially
catalytic active species and therefore they have been being applied as
heterogeneous catalysts of several organic reactions. We have been
studying the catalytic activity of novel MOFs and coordination
polymer structures in several organic transformations.[5b-5d, 14] MOFs
containing Ln ions act as efficient heterogeneous catalysts in the
cyanosilylation of aldehydes,[5c] specially without the use of solvents
and at 40 C or under ultrasonication.[16] The Co(II) centers of the
synthesized coordination polymers are fully coordinated with non
labile ligands and should not be catalytic active. The coordination
number of the Ln centers is 9, possessing as well water labile ligands.
Thus we explored the catalytic activity of coordination polymers 1 and
68
p-CH
n-C
Ph
3
Ph
100
99
6
H
13
21
48
3
95
a
3 6 13
Aldehyde: R=Ph, benzaldehyde; R=p-CH Ph, p-tolualdehyde ; and R=n-C H ,
heptaldehyde. b Conversion of the aldehyde determined by GC using an internal
o
[15]
standard (chlorobenzene). c Selectivity towards the aldehyde trimethylsilyl cyanide,
d
determined by GC.
Turnover number
=
moles of aldehyde trimethylsilyl
cyanide/moles of CP. e Turnover frequency = TON/reaction time. Second catalytic
f
cycle with solid recovery of only 56%.
The CP 1 was filtered from the reaction media and after washing
several times with dichloromethane and drying, it was reused in
another catalytic cycle under the same experimental conditions. The
solid recovery was only 56% and thus in the second catalytic cycle the
benzaldehyde conversion reached 68% in 48 h with high selectivity
3
in the synthesis of cyanohydrins at room temperature under
solventless conditions (Fig. 7). As can be seen from Fig. 9 and Table 2,
the coordination polymers 1 and 3 showed similar catalytic activities in
the conversion of benzaldehyde with trimethylsilyl cyanide (TMSCN)
into the corresponding cyanohydrin reaching 94% in 48 h with high
selectivity (98% for both) and turnover number (TON) of 34, for both,
(
96%). Due to the loss of material a lower amount of catalytic active
sites were available and thus a higher TON (43) was obtained in the
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second cycle, showing that there was not deactivation of the CP 1 upon
reuse. After the second cycle, the PXRD pattern of 1 is similar to the
as-synthesized one (Fig. S14).
40 mA). Scanning electron microscopy (SEM) and energy dispersive
analysis of X-ray spectroscopy (EDS) were performed using a Hitachi
S-4100 field emission gun tungsten filament instrument working at 25
kV. Samples were prepared by deposition on aluminium sample
holders with carbon coating.
The starting reagents used to prepare CPs 1 and 3 were also checked
for their catalytic activity under similar experimental conditions. The
results are compiled in Table 2 and it can be seen that although they
2 4 2 6 2
Synthesis of compounds [Ln Co(pzdc) (H O) ]·2H O {Ln = La (1),
were not soluble in the reaction mixture in the case of La
2 3 2 3
O and Eu O ,
Pr (2), Eu (3) and Gd (4) }
and only partially soluble in the case of Co(NO ·6H O, they are also
3
)
2
2
active but higher TON and comparable TOF were obtained with the
corresponding CPs 1 and 3. However in CPs 1 and 3 the cobalt(II) has
a fully coordinated sphere with non labile ligands. The Ln ions should
be the catalytic active site, probably via displacement of the labile
water molecules by aldehyde before its activation and reaction.[14,15]
Compounds 1–4 were obtained under the same experimental conditions.
In a general synthesis, a mixture containing H pzdc (0.2 mmol, 0.0336
g), Co(NO ·6H O (0.1 mmol, 0.0291 g) and La (0.05 mmol,
0.0163 g) [or Pr 11 (0.0170 g) or Eu (0.0176 g) or Gd (0.0181
g)] in 8 mL H O was kept in a Teflon-lined autoclave and placed inside
2
3
)
2
2
2 3
O
6
O
2
O
3
2 3
O
2
a preheated oven at 140 °C for 72 h. After the autoclave is cooled to
room temperature, yellow needlelike crystals of compound 1 suitable
for single-crystal X-ray diffration analysis were isolated from final
reaction products by filtration after washing several times with distilled
water, and dried in air at ambient temperature. The purities of the
samples were confirmed by PXRD studies and elemental analysis.
For 1, Yield: 31 mg, 54%. Anal. calcd for C H O N CoLa : C,
Conclusions
In summary, four new 3d–4f heterometallic TMLnCPs with the
2 4 2 6 2
molecular formula [Ln Co(pzdc) (H O) ]·2H O {Ln = La (1), Pr (2),
Eu (3) and Gd (4) were synthesized hydrothermally. Those compounds
feature a 3-D brick-like structure with rectangular-shaped nano-scale
pores, made up of wave-like layers of [La(pzdc)]+ unit which are
2
4
24 24
8
2
25.17; H, 2.11; N, 9.78%. Found: C, 25.30; H, 2.20; N, 9.66%. IR
-1
(KBr, cm ): 3340(br), 1651(s), 1624(s), 1586(s), 1566(s), 1469(m),
connected by 1-D chain of [Co(pzdc)
2
]2- unit. Compounds 1 and 3 were
1439(m), 1388(s), 1358(s), 1229(w), 1201(w), 1167(m), 1119(m),
1073(w), 989(w), 901(m), 851(m), 837(w), 785(m), 748(m), 617(m),
551(w), 430(m), 405(w), 363(m).
active in the room temperature for cyanosilylation of benzaldehyde
under solventless conditions, presenting similar catalytic activities.
Conversions of 94% with very high selectivities towards the
cyanohydrin were achieved within 48 h, whereas the control
experiment without use of catalyst only reached 16%. An aliphatic and
another aromatic aldehyde could also be converted into the
corresponding cyanohydrins in much shorter reaction time by
compound 1. And this compound could also be recycled by simple
filtration with a solid recovery of 56%, which conducted to a 68%
conversion in a second reuse using benzaldehyde within 48 h.
For 2, Yield: 29 mg, 50%. Anal. calcd for C H O N CoPr : C,
2
4
24 24
8
2
25.08; H, 2.10; N, 9.75%. Found: C, 25.19; H, 2.21; N, 9.69%. IR
-1
(KBr, cm ): 3330(br), 1651(s), 1626(s), 1587(s), 1566(s), 1470(m),
1439(m), 1388(s), 1358(s), 1229(w), 1201(w), 1167(m), 1120(m),
1073(w), 987(w), 900(m), 851(m), 837(w), 786(m), 748(m), 616(m),
551(w), 434(m), 399(w), 358(m).
For 3, Yield: 18 mg, 31%. Anal. calcd for C H O N CoEu : C,
2
4
24 24
8
2
24.61; H, 2.07; N, 9.57%. Found: C, 24.72; H, 2.13; N, 9.46%. IR
-1
(
KBr, cm ): 3330(br), 1656(s), 1622(s), 1588(s), 1565(s), 1473(m),
1
1
5
439(m), 1389(s), 1359(s), 1229(w), 1201(w), 1169(m), 1118(m),
071(w), 987(w), 902(m), 852(m), 839(w), 786(m), 749(m), 618(m),
51(w), 439(m), 402(w), 362(m).
Experimental Section
Materials and methods
For 4, Yield: 10 mg, 17%. Anal. calcd for C24
24 24 8 2
H O N CoGd : C,
2
4.39; H, 2.05; N, 9.48%. Found: C, 24.51; H, 2.12; N, 9.59%. IR
All the starting materials were of reagent quality and were obtained
from commercial sources without further purifications. Elemental
analyses for C, N and H were performed on a TruSpec 630-200-200
elemental analyser with a combustion furnace temperature of 1075 °C
and an afterburner temperature of 850 °C. FT-IR spectra were collected
from KBr pellets (Aldrich 99%+, FT-IR grade) on a Mattson 7000 FT-
-1
(
KBr, cm ): 3300(br), 1656(s), 1622(s), 1588(s), 1564(s), 1473(m),
1
1
5
439(m), 1390(s), 1360(s), 1229(w), 1202(w), 1170(m), 1119(m),
071(w), 990(w), 904(m), 852(m), 840(w), 785(m), 750(m), 616(m),
49(w), 439(m), 401(w), 360(m).
X-ray crystallographic analysis
-1
-1
IR spectrometer in a range of 4000–400 cm at the resolution of 2 cm .
Thermogravimetric analyses (TGA) were carried out using a Shimadzu
TGA 50 under air, from room temperature to ca. 700 ºC, with a heating
rate of 10 ºC/min. Powder X-ray diffraction (PXRD) patterns were
recorded at ambient temperature using an Empyrean diffractometer
with Cu-Kα radiation (λ = 1.54178 Å) in the 2θ range of 5 to 50° in
reflection mode, which is equipped with a X’Celerator detector, a
curved graphite-monochromated radiation and a flat-plate sample
holder, in a Bragg-Brentano para-focusing optics configuration (45 kV,
Single crystals with dimensions 0.18×0.16×0.12 mm for 1,
0
0
.12×0.06×0.04 mm for 2, 0.16×0.10×0.04 mm for 3, and
.08×0.06×0.04 mm for 4 were selected for indexing and intensity date
collection at 298 K on a Bruker SMART APEX-II CCD diffractometer
equipped with graphite-monochromatized Mo Kα (λ = 0.71073 Å)
radiation. A hemisphere of data was collected in the θ range 1.79–
2
6.00° for 1, 1.80–30.54° for 2, 1.80–28.43° for 3, and 1.81–30.61° for
using a narrow-frame method with scan widths of 0.30° in ω and an
4
exposure time of 10 s per frame. Numbers of measured and observed
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Zeitschrift für anorganische und allgemeine Chemie
10.1002/zaac.201700344
FULL PAPER
reflections [I>2σ(I)] are 15667 and 3343 (Rint = 0.0521) for 1, 20319,
temperature, 230 °C. The obtained products were confirmed using a
Finnigan Trace GC-MS. A blank experiment was also performed using
the same experimental procedure, but without addition of the
coordination polymers. Blank experiments using the same
5
1
139 (Rint= 0.0421) for 2, and 17437 and 4149 (Rint= 0.0480) for 3, and
9419 and 5034 (Rint= 0.0718) for 4, respectively. The data was
integrated using the Siemens SAINT program,[17] with the intensities
corrected for Lorentz factor, polarization, air absorption, and
absorption due to variation in the path length through the detector
faceplate.
experimental conditions and 0.06 mmol of La
mmol of Co(NO ·6H O were performed.
2 3 2 3
O or Eu O or 0.03
3
)
2
2
The structures were solved by direct method using SHELXS-97[18a]
and refined on F by full matrix least-squares using SHELXL-97.[18b]
All the non-hydrogen atoms were refined anisotropically. All H atoms
were refined isotropically. Crystallographic and refinement details are
listed in Table 3. Selected bond lengths are given in Table 1. CCDC
reference numbers: 1412437–1412440 correspond to compounds 1–4,
respectively.
Acknowledgements
2
F.-N. SHI acknowledges the project of NSFC (No. 21571132). T.-H.
Yang acknowledges the Changzhou Sci&Tech Program (Grant No.
CJ20179015) and FCT (Portugal, Ref. SFRH/BPD/74582/2010). This
work was also developed within the scope of the project CICECO-
Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT
Ref. UID/CTM/50011/2013), financed by national funds through the
FCT/MEC and when appropriate co-financed by FEDER under the
PT2020 Partnership Agreement.
Table 3 Crystallographic data for compounds 1–4
Compound
Empirical
formula
F. w.
1 (La)
2 (Pr)
3 (Eu)
4 (Gd)
C
24
H
24
O
24
C
24
H
24
O
24
C
24
H
24
O
24
C
24
H
24
O
24
2
N
8
CoLa
1145.26
Monoclinic
2
N
8
CoPr
1149.26
Monoclinic
2
N
8
CoEu
1171.36
Monoclinic
2
N
8
CoGd
1181.94
Monoclinic
Keywords: Pyrazine-2,3-dicarboxylic acid • Heterometal coordination
polymers • Lanthanides • Catalytic property
Crystal
system
Space group
a ( Å)
P2
1
/n
P2
1
/n
P2
1
/n
P2
1
/n
References
6.1931(2)
22.8075(7)
12.0453(3)
91.529(2)
1700.78(9)
2
6.1928(2)
22.6837(7)
12.0136(4)
91.843(2)
1686.74(9)
2
6.1595(10)
22.586(4)
11.9565(16)
92.012(6)
1662.3(4)
2
6.1408(9)
22.559(3)
11.9321(16)
92.102(8)
1651.9(4)
2
b ( Å)
[1] a) M. Sakamoto, K. Manseki, H. Okawa, Coord. Chem. Rev. 2001, 219, 379-414;
b) C. Benelli and D. Gatteschi, Chem. Rev. 2002, 102, 2369-2387; c) C. E.
Plecnik, S. M. Liu, S. G. Shore, Accounts. Chem. Res. 2003, 36, 499-508; d) O.
Oms, A. Dolbecq and P. Mialane, Chem. Soc. Rev. 2012, 41, 7497-7536;e) J.-L.
Liu, Y.-C. Chen, F.-S. Guo, M.-L. Tong, Coord. Chem. Rev. 2014, 281, 26-49.
[2] a) J.-B. Peng, Q.-C. Zhang, X.-J. Kong, Y.-P. Ren, L.-S. Long, R.-B. Huang, L.-S.
Zheng, Z. Zheng, Angew. Chem. Int. Edit. 2011, 50, 10649-10652; b) J. Rinck, G.
Novitchi, W. Van den Heuvel, L. Ungur, Y. Lan, W. Wernsdorfer, C. E. Anson,
L. F. Chibotaru, A. K. Powell, Angew. Chem. Int. Edit. 2010, 49, 7583-7587; c) P.
F. Shi, G. Xiong, B. Zhao, Z. Y. Zhang, P. Cheng, Chem. Commun. 2013, 49,
2338-2340; d) J. B. Peng, Q. C. Zhang, X. J. Kong, Y. Z. Zheng, Y. P. Ren, L. S.
Long, R. B. Huang, L. S. Zheng, Z. P. Zheng, J. Am. Chem. Soc. 2012, 134,
3314-3317; e) Y. H. Su, S. S. Bao and L. M. Zheng, Inorg. Chem. 2014, 53,
6042-6047; f) S. M. T. Abtab, M. Maity, K. Bhattacharya, E. C. Sanudo, M.
Chaudhury, Inorg. Chem. 2012, 51, 10211-10221; g) Q. Yue, J. Yang, G. H. Li,
G. D. Li, W. Xu, J. S. Chen, S. N. Wang, Inorg. Chem. 2005, 44, 5241-5246; h)
H. Xiang, W. G. Lu, W. X. Zhang, L. Jiang, Dalton Trans. 2013, 42, 867-870; i)
N. Xin, Y.-Q. Sun, Y.-N. Han, D. Z. Gao, Z Anorg Allg Chem 2016, 642, 1460-
c (Å)
β (°)
V( Å3)
Z
D
c
(g/cm3)
2.236
2.263
2.340
2.376
-1
μ (mm )
3.062
3.443
4.336
4.581
F(000)
1114
1122
1138
1142
GOF on F2
1.070
1.003
1.001
1.003
a
R
1
, wR
2
0.0315,
0.0659
0.0393,
0.0697
1.702,
0.0309,
0.0547
0.0415,
0.0576
1.072,
0.0297,
0.0589
0.0384,
0.0623
1.127,
0.0484,
0.0622
0.0574,
0.0694
0.949,
[
I>2σ(I)]
a
1 2
R , wR
(
(
(
All date)
Δρ)max,
Δρ)min (eÅ-
-0.694
-0.610
-0.812
-1.032
3)
aR
2
1/2
1
o c o 2 o c o
= Σ||F | - |F ||/Σ|F |, wR ) ]
= [Σw(F 2 - F 2)2/Σw(F 2
Catalysis experiments
1
2
465; j) X. Wang, H. Li, J. Sun, M. Yang, C. Li, L. Li, New J Chem 2017, 41,
The cyanosilylation of aldehydes were performed at room
temperature in closed batch reactors using 1.00 mmol of aldehyde, 0.50
mmol of chlorobenzene (internal standard), 2.00 mmol of trimethylsilyl
cyanide (TMSCN), 0.0300 g of 1 or 3 (2.6% mol relatively to the
aldehyde), previously dried at 120 °C under vacuum for 3 h. The
reaction was followed by GC, by withdrawing periodically aliquots
from the reaction mixture, using a Bruker 450 GC gas chromatograph
equipped with a fused silica Varian Chrompack capillary column VF-5
ms (15 m × 0.15 mm id; 0.15 µm film thickness), using helium as
carrier gas. Conditions used: 60 °C (3 min), 5 °C/min, 170 °C (2 min),
973-2979.
[
3] a) R. Feng, L. Chen, Q.-H. Chen, X.-C. Shan, Y.-L. Gai, F.-L. Jiang, M.-C. Hong,
Cryst. Growth Des. 2011, 11, 1705-1712; b) X. D. Zhu, Z. J. Lin, T. F. Liu, B.
Xu, R. Cao, Cryst. Growth Des. 2012, 12, 4708-4711; c) L. Liang, G. Peng, L.
Ma, L. Sun, H. Deng, H. Li, W. S. Li, Cryst. Growth Des. 2012, 12, 1151-1158; d)
G. Peng, L. Ma, L. Liang, Y. Z. Ma, C. F. Yang, H. Deng, CrystEngComm 2013,
1
5, 922-930; e) Q. B. Bo, H. Y. Wang, D. Q. Wang, Z. W. Zhang, J. L. Miao, G.
X. Sun, Inorg. Chem. 2011, 50, 10163-10177; f) X. P. Yang, C. Chan, D. Lam, D.
Schipper, J. M. Stanley, X. Y. Chen, R. A. Jones, B. J. Holliday, W. K. Wong, S.
C. Chen, Q. Chen, Dalton Trans. 2012, 41, 11449-11453.
2
0 °C/min, 200 °C (10 min); injector temperature, 200 °C; detector
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10.1002/zaac.201700344
FULL PAPER
[
4] a) Y. Wang, P. Cheng, J. Chen, D.-Z. Liao, S.-P. Yan, Inorg. Chem. 2007, 46,
142-147; e) Q. Yang, G. Xie, Q. Wei, S. Chen, S. Gao, J. Solid State Chem. 2014,
215, 26-33.
4530-4534; b) C. J. Li, Z. J. Lin, M. X. Peng, J. D. Leng, M. M. Yang, M. L.
Tong, Chem. Commun. 2008, 6348-6350; c) H.-M. Peng, H.-G. Jin, Z.-G. Gu, X.-
J. Hong, M.-F. Wang, H.-Y. Jia, S.-H. Xu, Y.-P. Cai, Eur. J. Inorg. Chem. 2012,
[11] a) J. R. Li, J. Sculley, H. C. Zhou, Chem. Rev. 2012, 112, 869-932; b) H. H. Wu,
Q. H. Gong, D. H. Olson, J. Li, Chem. Rev. 2012, 112, 836-868; c) L. E. Kreno,
K. Leong, O. K. Farha, M. Allendorf, R. P. Van Duyne, J. T. Hupp, Chem. Rev.
2012, 112, 1105-1125; d) J. R. Li, R. J. Kuppler, H. C. Zhou, Chem. Soc. Rev.
2009, 38, 1477-1504; e) J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T.
Nguyen, J. T. Hupp, Chem. Soc. Rev. 2009, 38, 1450-1459.
5562-5570; d) M. Fang, B. Zhao, Y. Zuo, J. Chen, W. Shi, J. Liang, P. Cheng,
Dalton Trans. 2009, 7765-7770.
[
5] a) O. V. Amirkhanov, O. V. Moroz, K. O. Znovjyak, T. Y. Sliva, L. V. Penkova,
T. Yushchenko, L. Szyrwiel, I. S. Konovalova, V. V. Dyakonenko, O. V.
Shishkin, V. M. Amirkhanov, Eur. J. Inorg. Chem. 2014, 3720-3730; b) T.-H.
Yang, A. R. Silva, F.-N. Shi, Dalton Trans. 2013, 42, 13997-14005; c) T.-H.
Yang, A. R. Silva, F.-N. Shi, CrystEngComm 2015, 17, 3852-3858; d) T.-H.
Yang, A. R. Silva, L. S. Fu, F.-N. Shi, Dalton Trans. 2015, 44, 13745-13751.
6] a) S. Zhang, J. Zhao, P. Ma, J. Niu, J. Wang, Chem. Asian J. 2012, 7, 966 – 974;
b) J. Y. Niu, S. W. Zhang, H. N. Chen, J. W. Zhao, P. T. Ma, J. P. Wang, Cryst.
Growth Des. 2011, 11, 3769−3777.
[12] a) A. Kobayashi, Y. Suzuki, T. Ohba, S.-i. Noro, H.-C. Chang, M. Kato, Inorg.
Chem. 2011, 50, 2061-2063; b) S.-Y. Liao, W. Gu, L.-Y. Yang, T.-H. Li, J.-L.
Tian, L. Wang, M. Zhang, X. Liu, Cryst. Growth Des. 2012, 12, 3927-3936; c)
H.-Y. Liu, Y.-J. Yuan, Z.-T. Yu, Z.-G. Zou, CrystEngComm 2011, 13, 2391-2398;
d) Z.-Y. Li, Y. Dai, H. Zhang, J. Zhu, J.-J. Zhang, S.-Q. Liu, C.-Y. Duan, Eur. J.
Inorg. Chem. 2014, 384-391.
[
[
[13] V. A. Blatov, A. P. Shevchenko, TOPOS–Version Professional beta evaluation,
Samara State University, Samara, Russia, 2006.
7] a) Y. Zhou, M. Hong, X. Wu, Chem. Commun. 2006, 135-143; b) F. Luo, Y.-T.
Yang, Y.-X. Che, J.-M. Zheng, CrystEngComm 2008, 10, 1613-1616; c) C.-J.
Shen, S.-M. Hu, T.-L. Sheng, Z.-Z. Xue and X.-T. Wu, Dalton Trans. 2015, 44,
[14] a) F.-N. Shi, A. R. Silva, J. Rocha, J Solid State Chem. 2011, 184, 2196-2203; b)
F. N. Shi, A. R. Silva, T. H. Yang, J. Rocha, CrystEngComm 2013, 15, 3776-
3779; c) F.-N. Shi, A. R. Silva, L. Bian, J Solid State Chem, 2015, 225, 45-52.
[15] R. F. D Vries, V. A. de la Peꢀa-O’Shea, N. Snejko, M. Iglesias, E. Gutiꢁrrez-
Puebla, M. ꢂngeles Monge, Cryst. Growth Des. 2012, 12, 5535−5545.
[16] Y. Zhu, Y. Wang, P. Liu, C. Xia, Y. Wu, X. Lu, J. Xie, Dalton Trans. 2015, 44,
1955–1961.
6510-6515.
[
8] a) Y.-Q. Sun, J. Zhang, G.-Y. Yang, Chem. Commun. 2006, 4700-4702; b) S.-L.
Cai, S.-R. Zheng, Z.-Z. Wen, J. Fan, W.-G. Zhang, CrystEngComm 2012, 14,
8236-8243. c) X. Feng, Y.-Q. Feng, J. J. Chen, S.-W. Ng, L.-Y. Wang, J.-Z. Guo,
Dalton Trans. 2015, 44, 804-816;
[
9] a) P. Mahata, G. Sankar, G. Madras, S. Natarajan, Chem. Commun. 2005, 5787-
[17] SAINT+, Data Integration Engine, v. 7.23a, Bruker AXS, Madison, Wisconsin,
1997-2005.
5789; b) M. Li, J. F. Xiang, L. J. Yuan, S. M. Wu, S. P. Chen, J. T. Sun, Cryst.
Growth Des., 2006, 6, 2036-2040.
[18] a) G. M. Sheldrick, SHELXS-97, Program for Crystal Structure Solution,
University of Göttingen, Germany, 1997; b) G. M. Sheldrick, SHELXL-97,
Program for Crystal Structure Refinement, University of Göttingen, Germany,
1997.
[
10] a) Y. Liang, M. Hong, R. Cao, W. Sun, Y. Zhao, Y.-P. Weng, J. Zhang, R. Xiong,
Bull. Chem. Soc. Jpn. 2002, 75, 1521-1526; b) A. E. Ion, E. T. Spielberg, L.
Sorace, A. Buchholz, W. Plass, Solid State Sci. 2009, 11, 766-771; c) Y.-Q. Sun,
L. Wu, L.-L. Fan, G.-Y. Zhang, Y.-Y. Xu, D.-Z. Gao, Z. Anorg. Allg. Chem.
2012, 638, 427-432; d) Q. Wei, S. Zhang, Q. Yang, S.-P. Chen, W.-J. Gong, Y.-P.
Zhang, G.-C. Zhang, C.-S. Zhou, S.-L. Gao, Z. Anorg. Allg. Chem. 2013, 639,
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Entry for the Table of Contents
FULL PAPER
Four CoLn porous 3d–4f heterometallic
Heterometallic Coordination Polymers
coordination polymers constructed from
the pzdcH
2
ligand were hydrothermally
Ting-Hai Yang,* Ana Rosa Silva,
Lianshe Fu, and Fa-Nian Shi*
synthesized and characterized. Their
catalytic properties in the cyanohydrins
reaction were investigated. They showed
similar catalytic activities with very high
conversions of benzaldehyde and high
selectivity.
Page No. – Page No.
Synthesis, Crystal Structure,
Topology and Catalytic Property of
Porous 3d–4f Heterometallic
Coordination Polymers Constructed
From Pyrazine-2,3-dicarboxylic Acid
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