ARTICLE pubs.acs.org/crystal
Zinc Coordination Polymers with 2,6-Bis(imidazole-1-yl)pyridine and Benzenecarboxylate: Pseudo-Supramolecular Isomers with and without Interpenetration and Unprecedented Trinodal Topology Jhen-Yi Lee,† Chih-Yuan Chen,† Hon Man Lee,*,† Elisa Passaglia,‡ Francesco Vizza,§ and Werner Oberhauser*,§ †
Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan, R.O.C. ICCOM-CNR, UOS Pisa, Area della Ricerca, via Moruzzi, 1, 56124, Pisa, Italy § Istituto di Chimica dei Composti Organometallici (ICCOM-CNR), Area di Ricerca CNR di Firenze, via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy ‡
bS Supporting Information ABSTRACT: The ligand combination of semirigid 2,6-bis(imidazole-1-yl)pyridine (2,6-bip) and rigid benzenecarboxylate allow the isolation of three new zinc coordination polymers. Hydrothermal synthesis between Zn(NO3)2 3 6H2O, 2,6bip, and terephthalic acid under basic condition affords [Zn(1,4-bdc)(2,6-bip) 3 2 H2O]n (1) (1,4-bdc =1,4-benzenedicarboxylate), which shows an undulating 2D (4,4)-network with 2-fold interpenetration. Contrastingly, solvothermal synthesis with identical starting materials in DMF, yields [Zn(1,4-bdc)(2,6-bip) 3 DMF]n (2), which exhibits noninterpenetrating 2D (4,4)-network. Thus 1 and 2 are pseudosupramolecular isomeric pair, illustrating the strong effect of guest solvents in controlling the entanglement. A similar hydrothermal reaction to 1 but using 1,3,5benzenetricarboxylic acid instead yields [Zn2(μOH)(1,3,5-btc)(2,6-bip) 3 H2O]n (3) (btc = benzenetricarboxylate), which exhibits a (3,4,6)-connected 3D framework with an unprecedented {5.6.7}2{52.6.7.82}2{54.62.73.84.92} topology. Compound 1 and 2 show reversible solvent incorporation properties.
’ INTRODUCTION Crystal engineering to synthesis rationally coordination polymers (CPs) or metalorganic frameworks (MOFs) attract much interest because of their potential applications as functional materials15 in gas storage,6 separation,7 catalysis,8,9 drug delivery,10,11 the embedding of nanoparticles,12 etc. Their fascinating architectures and topological networks also account for their wide interest.1316 The use of rigid ligands, such as 4,40 -bipyridine (4,40 -bpy)17,18 and 1,4-benzenedicarboxylate (1,4-bdc),19,20 to obtain porous CPs have been well-documented. Recently, there is also a growing trend in using flexible ligands to obtain intriguing network architectures.21 The use of flexible ligands not just allows the construction of coordination network with special properties and structures, but also provides opportunities to understand the details of a self-assembly process. However, in general, construction of CPs based on flexible ligands is difficult; the control in the final architectures is poor because of the possibility of diverse ligand conformations and the structural characterizations are somewhat more challenging.21 Previously, we employed 2,6-bis(imidazole-1-yl)pyridine (2,6bip) to construct chiral 1D zinc CPs of helical and zigzag chains.22 The ligand is a hingelike molecule,23,24 allowing certain degree of rotations around the CN bonds between the three rings. Thus such semirigid ligand allows slight conformational changes for the r 2011 American Chemical Society
potential assembly of different network architectures, but at the same time, greatly avoids the above-mentioned problems associated with flexible ligands. Thus, contrasting to the recent trend in using flexible ligands to obtain intriguing network architectures,21 we employed a combination of semirigid 2,6-bip ligand and an additional rigid ligand of benzenecarboxylate to construct novel multidimensional (2D and 3D) zinc CPs. The strategy successfully yields three new polymeric materials, {Zn(1,4-bdc)(2,6-bip) 3 2H2O}n (1), {Zn(1,4-bdc)(2,6bip) 3 DMF}n (2), and [Zn2(μOH)(1,3,5-btc)(2,6-bip) 3 H2O]n (3). Notably, 1 and 2 are 2D pseudo-supramolecular isomers,25,26 which shows undulating (4,4) networks with and without interpenetration, respectively. Compound 3 exhibits a 3D array with an unprecedented topology. The networks in 1 and 2 show reversible solvent incorporation properties.
’ RESULTS AND DISCUSSION Synthesis of CPs. Compound 1 was prepared under hydrothermal condition by heating a basic mixture (pH = 79) of Received: November 1, 2010 Revised: February 10, 2011 Published: March 11, 2011 1230
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Figure 1. Coordination environments in 1 and 2 with thermal ellipsoids shown at 50% probability.
Figure 2. Schematic diagram of the 2D (4,4) nets in 1 and 2, respectively. The net of 2 is more corrugated.
Zn(NO3)2 3 6H2O, 2,6-bip, and terephthalic acid with a mole ratio of 1: 1: 1 at 140 C. Compound 2 was prepared under solvothermal condition by heating an identical mixture in DMF at 140 C without pH adjustment. Compound 3 was also prepared under hydrothermal condition by heating a similar basic mixture of Zn(NO3)2 3 6H2O, 2,6-bip, and 1,3,5-benzenetricarboxylic acid with a mole ratio of 1:1:1 in DMF at 140 C. Structural Description of 1. The asymmetric unit of 1 consists of a Zn atom, one molecule each of 2,6-bip and 1,4-bdc ligands, and two water solvent molecules (Table 1). The Zn atom shows a distorted tetrahedron coordination geometry with two coordinated 1,4-bdc ligands and two 2,6-bip ligands (Figure 1). The bond angles at the Zn center are in the range of 100.41(18)117.90(19) (Table 2). The 2,6-bip ligand is in anticonformation such that the NCN protons of the imidazole rings point in opposite direction. The imidazolyl rings are twisted from the pyridyl ring. The interplanar angles are 12.3(2) and 27.6(2), respectively. The semirigid nature of the 2,6-bip is, in fact, manifested by the three different sets of interplanar angles between the imidazoyl and pyridyl rings in 13 (vide infra). The two types of ligands act as connectors linking four-connected Zn atoms into an undulating or corrugated 2D (4,4) net,2734 which is a common network with (44 3 62) topology. There are two types of parallelograms in this uninodal 2D network (Figure 2). The dimensions of the smaller polygons are 10.957 11.186 Å with angles of 67.61 and 112.39 (defined by Zn 3 3 3 Zn separation and Zn 3 3 3 Zn 3 3 3 Zn angles, respectively). The dimensions of the others are 11.017 11.186 Å with angles of 81.87 and 98.13. The degree of undulation can be reflected from the dihedral angle between these two types of polygons, which is 115.9. Interestingly, a pair of (4,4) sheets involved in parallel 2-fold interpenetration is depicted in Figure 3. These entangled layers pack along [010] direction. The
interpenetration effectively reduced the solvent voids, in which lattice water molecules reside. The solvent-accessible volume is ∼151.9 Å3 per unit cell, and the pore volume ratio was calculated to be 15.1% by the PLATON program.35 {[Cd(tp)(bpt)(H2O)]2 3 (DMF) 3 1.5(H2O)}n (tp = terephthalic acid; bpt = bis(4-pyridyl)-4-amino-1,2,4-triazole) was a relevant example with 2-fold interpenetration similar to that in 1.29 Structural Description of 2. The asymmetric unit of 2 consists of a Zn atom, one molecule each of 2,6-bip and 1,4-bdc ligands, and a DMF solvent molecule. The bond distances in 1 and 2 are essentially similar but there are subtle differences in their NZnO bond angles. The angles in 1 fall in the range of 100.41(18)117.90(19) (Table 2), whereas those in 2 are in the range of 99.15(11) to 122.81(11). In both cases the 2,6-bip assumes an anticonformation. In contrast to 1, one of the imidazolyl rings is almost coplanar with the pyridyl ring but the other one is highly twisted. The respective interplanar angles are 3.3(1) and 51.9(1), respectively. The structure also consists of undulating 2D net of (44.62) topology. Two types of parallelograms are also present. Due to the different degree of ZnN bond rotation in 1 and 2, their conformations around the zinc atoms are different such that their resultant (4.4) sheets are of different geometries. The sheets in 2 are more corrugated than those in 1, reflecting from a smaller dihedral angle of 79.4 between the types of polygons in 2. The type of parallelograms with smaller areas consist of dimensions of 10.877 10.935 Å with angles of 62.75 and 117.25, whereas those of larger one are 10.876 11.071 Å with angles of 70.69 and 109.31. Intriguingly, in sharp contrast to the structure of 1, no interpenetration was observed in 2. The fourconnected sheets stack along [100] direction in AAA fashion with a separation of 6.577 Å between sheets. Nonclassical hydrogen bonds exist between phenyl ring protons on C7 atoms and carboxylate O4 atoms [CH 3 3 3 O = 2.59 Å and — CH 3 3 3 O = 140.3] and imidazole ring protons on C2 and C11 atoms and carboxylate O3 and O4 atoms, respectively [CH 3 3 3 O = 2.58 Å and — CH 3 3 3 O = 126.5; CH 3 3 3 O = 2.35 Å and — CH 3 3 3 O = 174.2], linking the sheets into a 3D network (Table S1 in the Supporting Information). The stacking of sheets results in two types of infinite open channels and DMF solvent molecules residue inside those channels with larger pore area (Figure 4), forming nonclassical hydrogen bonds with the network [CH 3 3 3 O = 2.27 and 2.50 Å and — CH 3 3 3 O = 162.4 and 157.9, respectively]. The noninterpenetrating nature of the network results in a larger total solvent-accessible volume of ∼257.8 Å3 per unit and the pore volume ratio was calculated to be 23.9%. The role of solvents as structure-directing agents in CPs still need more attention for their better understandings, regarding 1231
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Figure 3. Schematic diagram illustrating two 2D parallel interpenetrating networks in 1 and stacking of noninterpentrating networks in 2.
Figure 4. View of the 2D (4,4) sheet in 2. Hydrogen bonds are drawn in broken lines. DMF solvents are drawn in yellow.
the correlation of the framework structure with the solvent size, shape, and noncovalent binding properties.3638 The pseudosupramolecular isomeric pair of 1 and 2, both of which show (4,4)-net topology and differ only with and without interpenetration, clearly demonstrate that the presence of the larger solvent molecules (DMF vs H2O) during the self-assembly process effectively avoids the interpenetration of the (4,4) sheets. A pseudo-supramolecular isomeric pair somewhat relevant to 1 and 2 is [Zn(4,40 -bpy)2(SiF6)]n 3 xDMF39 and [Zn(4,40 -bipy)2(SiF6) 3 2H2O]n.40 While the former compound with guest DMF molecules shows a porous noninterpenetrating 3D structure of pcu topology, the latter compound with guest H2O molecules exhibits an inclined interpenetrating 2D grid structure. It has been shown that the effect of pH exerts a profound influence on the structures of CPs.4143 Because 1 was obtained at high initial pH condition in water and 2 was prepared in DMF without pH adjustment, it would be of interest to see if the pseudo-supramolecular isomer like 2 would be produced at low pH in water. Thus we carried out hydrothermal synthesis from a mixture of Zn(NO3)2 3 6H2O, 2,6-bip, and terephthalic acid at different initial pH values (2.6, 4.7, and 10.6). The initial pH of the solution without addition of extra acid or base was 4.7. The more acidic condition was achieved by the addition of HNO3 whereas the basic condition was obtained by the addition of triethylamine (vide supra). Because of the facile deprotonation of terephthalic acid to form 1,4-bdc under alkaline condition, 1 was obtained readily at high pH of 10.6. Contrastingly, neither 1 nor 2 (containing H2O instead of DMF) was obtained under acidic
Figure 5. Coordination environments in 3 with thermal ellipsoids shown at 50% probability.
condition. According to preliminary structural studies, the crystalline material obtained at pH 4.7 was a Zn CP with 2,6-bip ligand only and that at pH 2.6 was a Zn CP with 2,6-bip and oxalate that presumably derived from the decomposition of terephthalic acid. Hence, the pseudo-supramolecular isomer like 2 could not be obtained in water under either acidic or basic conditions but was rather readily obtained by switching the solvent to DMF. Structural Description of 3. The asymmetric unit consists of two Zn atoms bridged by an O atom, one molecule each of 1,3,5-btc and 2,6-bip, and one diffuse water solvent molecule (Figure 5). The Zn1 atom exhibits in square pyramidal coordination geometry, coordinated by four equatorial carboxylate O atoms of four different 1,3,5-btc ligands and an axial μ-hydroxy O atom. A pair of Zn1 atoms bridged by four 1,3,5-btc ligands form the paddle-wheel cluster, constituting the octahedral [Zn2(CO2)4O2] secondary building unit (SBU).19 Notably, [Zn2(CO2)4] is a common square planar SBU19,4448 and due to the presences of two “axial” O atoms from the μOH ligands in the paddle-wheel cluster of 3, the octahedral [Zn2(CO2)4O2] SBU is formed. It is also noteworthy that although CPs featuring [Zn2(CO2)4] with “axial” N atoms are common in the literature,4952 3 contains the first example of octahedral [Zn2(CO2)4O2] SBU. The Zn2 atom is in distorted tetrahedral coordination geometry, coordinated by two N atoms from two 1232
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Figure 6. Network perspective in 3 along approximately a-axis (left) and c-axis (right). Color code: yellow, four-connected node; pink, three-connected node; gray, six-connected node.
Figure 7. Variable-temperature XRPD spectra for 1. Asterisks denote diffraction contributions from heating chamber window material and the sample holder.
Figure 8. Selected XRPD spectra, acquired at room temperature, that confirm the reversible water incorporation in 1: (a) 1; (b) dehydrated 1, after heating it at 150 C in a heating chamber under N2 (asterisk denotes contribution from heating chamber window material); (c) after exposure of dehydrated 1 to H2O vapor.
different 2,6-bip ligands, a carboxylate O atom from 1,3,5-btc, and a μ-hydroxyl O atom. The bond angles at the Zn2 atom fall in the range of 99.88(19)127.75(19) (Table 3). Similar to 2, one of the imidazolyl rings is almost coplanar with the pyridyl ring but the other
Figure 9. Selected XRPD spectra, acquired at room temperature, that corroborate the reversible incorporation of DMF in 2: (a) 2; (b) desolvated 2 after removing DMF from the crystal lattice at 150 C in a heating chamber under N2 (asterisk denotes contribution from heating chamber window material); (c) after exposure of desolvated 2 to neat DMF at room temperature.
one, contrastingly, is less twisted (interplanar angle = 4.5(2) and 26.7(2), respectively). The topology of 3 was analyzed by TOPOS software,53 revealing an unprecedented topology. The 1,3,5-btc ligand can be considered as a three-connected node and Zn2 as a distorted four-connected node. The Zn2(CO2)4O2 SBU acts as a six-connected node. On the basis of this simplification, 3 exhibits a new 3D (3,4,6)connected trinodal topology (Figure 6). The point symbol54 for the 3D net is (5.6.7)2(52.6.7.82)2(54.62.73.84.92). The vertex symbols for the three-, four-, and six-connected nodes are [5.6.72] [5.72.5.82.6.83], [5.5.5.5.6.6.7.7.72.82.82.84.84.*.*], respectively. The solvent-accessible volume is ∼238.3 Å3 per unit cell, and the pore volume ratio was calculated to be 10.9%. None of the (3,4,6)-connected 3D networks of CPs in the literature shows the same topology of 3. The 3D networks with point symbol of (63)(65.8)(612.8 102) in {[Co2(Hbidc)2(bpt)2] 3 7H2O}n55 (Hbidc =1H-benzimidazole-5,6dicarboxylate; bpt =1H-3,5-bis(4-pyridyl)-1,2,4-triazole) and that of (43)(44.62)(46.79) in {[Zn7L2(OH)2(H2O)9] 3 12.25H2O}n48 [L = 5,50 ,500 -(2,4,6-trimethylbenzene-1,3,5-triyl) trismethylene-trisoxytriisophthalate] are the only two previously examples of (3,4,6)connected nets in CPs. It is noteworthy to point out that 1 and 3 were synthesized under similar hydrothermal conditions, yet the use of different 1233
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benzenecarboxylate (ditopic vs tritopic ligands) led to diverse topologies (2D interpenetrated 4-connected net vs 3D (3,4,6)connected trinodal net). Interestingly, the use of 1,4-bdc ligands afforded only the simple tetrahedral 4-connected nodes in 1, whereas the Zn(II) ions constitute the simple 4-conected nodes as well as the octahedral SBUs (cluster nodes) with 1,3,5btc ligands in 3, leading to the subsequent structure of higher dimensionality. Thermal Stability of 1-3. In order to determine the thermal stability of 13, thermogravimetric (TG) analyses on polycrystalline samples of the latter compounds were carried out in the
Figure 10. CP-MAS 13C{1H} NMR spectra of solvent containing ZnCPs acquired at a sample spinning rate of 10 kHz; (a) 1 containing MeOH instead of H2O; (b) 1 containing EtOH instead of H2O; (c) 2. S denotes NMR signals stemming from incorporated solvent molecules. Weak NMR signals in the chemical shift range 10 to 80 ppm are rotation side bands.
presence of a nitrogen atmosphere (see Figure S1 in the Supporting Information). The TG curves of 13 confirmed the presence of solvent molecules in the crystal lattice, i.e., 2H2O in 1 (found 6.5%; calcd 7.5%), DMF in 2 (found 10.7%; calcd 14.2%) and diffuse H2O in 3 (found 5.8%; calcd 3.1%). The decomposition of the Zn-CP network started at an onset temperature of 298 C (1), 385 C (2) and 312 C (3), releasing first the nitrogen ligand and yielding ZnO (hexagonal P63mc) as the only crystalline residue. The formation of ZnO in the course of the decomposition process was proved by independent variable-temperature X-ray powder diffraction (XRPD) studies carried out in a heating chamber under nitrogen applying a heating rate identical to that used for TG analysis. Figure 7 shows a representative sequence of XRPD spectra acquired in the course of the variable-temperature XRPD study of 1, corroborating the formation of ZnO at 350 C. Reversible Solvent Incorporation in 1 and 2. Dehydrated 1, which was obtained by heating 1 at 150 C in a heating chamber under nitrogen, was exposed in independent experiments at room temperature to water vapor, MeOH vapor and neat EtOH. The reversible incorporation of two molecules of water in dehydrated 1 is nicely proved by comparing the XRPD pattern of 1 (Figure 8, trace a) with that obtained after the rehydration process (trace c). The incorporation of one molecule of MeOH per asymmetric unit of dehydrated 1 has been confirmed by TG analysis (see Figure S2a in the Supporting Information), that showed a weight loss of 7.3% (calcd 6.8%) at 66.9 C, whereas EtOH is only partially incorporated (i.e., 0.75 molecules per asymmetric unit) in the crystal lattice of dehydrated 1, as proved by TG analysis (see Figure S2b in the Supporting Information). Moreover, the successful substitution of water by MeOH and EtOH in 1 is clearly shown by a comparison of the corresponding XRPD pattern with that of 1 (see Figure S3 in the Supporting Information).
Table 1. Crystallographic Data of 13 1
a
2
3
empirical formula
C19H13N5O4Zn 3 2H2O
C19H13N5O4Zn 3 C3H7NO
C20H13N5O7Zn2 3 H2O
fw
476.75
513.81
584.14
cryst size (mm3)
0.25 0.20 0.15
0.25 0.20 0.20
0.25 0.20 0.18
cryst system
triclinic
triclinic
monoclinic
space group
P1
P1
P21/c
a (Å)
9.272(2)
6.5769(11)
11.526(2)
b (Å)
10.852(3)
10.8765(18)
14.485(3)
c (Å) R (deg)
11.186(3) 87.315(6)
15.686(3) 98.094(5)
13.108(3) 90
β (deg)
72.896(6)
101.276(3)
95.727(4)
γ (deg)
69.683(6)
96.389(4)
90
V (Å3)
1007.0(4)
1078.3(3)
2177.6(7)
T, K
150(2)
150(2)
150(2)
Z
2
2
4
reflns collected
12882
11815
30449
independent reflns params refined
4386 280
4706 309
5674 338
GOF on F2
1.024
1.022
1.024
R1a [I > 2σI]
0.0687
0.0510
0.0678
wR2b (all data)
0.1977
0.1316
0.2047
R1 = Σ(||Fo| |Fc||)/Σ |Fo|. b wR2 = [Σ(|Fo|2 |Fc|2)2/Σ (Fo2)]1/2. 1234
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Table 2. Selected Bond Distances (Å) and Angles (deg) of 12a 1
a
2
Zn1N1
2.007(5)
Zn1N1
2.021(3)
Zn1N5A
2.022(5)
Zn1N5B
2.018(3)
Zn1O1
1.951(4)
Zn1O1
1.933(3)
Zn1O3
1.954(4)
Zn1O3
1.968(3)
N1Zn1O1
117.90(19)
N1Zn1O1
122.81(11)
N5Zn1O3 N1Zn1N5
110.26(19) 107.36(19)
N5BZn1O3 N1Zn1N5B
114.82(12) 106.17(12) 106.07(11)
O1Zn1O3
106.40(19)
O1Zn1O3
O1Zn1N5A
100.41(18)
O1Zn1N5B
99.15(11)
O3Zn1N1
113.65(19)
O3Zn1N1
108.03(12)
Symmetry code: A = x, y, z 1; B = x, y 1, z.
Table 3. Selected Bond Distances (Å) and Angles (deg) of 3a Zn1O1
1.928(4)
Zn2N1
Zn1O4D
2.039(4)
Zn2N5A
2.033(5) 2.013(5)
Zn1O5B
2.062(4)
Zn2O1
1.902(4)
Zn1O6E Zn1O7C
2.060(4) 2.060(4)
Zn2O2
1.967(4)
O1Zn1O4D
105.06(17)
O1Zn2N1
113.29(19)
O1Zn1O6E
102.20(17)
O1Zn2O2
106.80(18)
O1Zn1O7C
102.47(17)
O1Zn2N5A
104.77(18)
O1Zn1O5B
99.07(16)
N1Zn2N5A
104.4(2)
O4DZn1O6E
94.06(17)
N1Zn2O2
O4DZn1O7C
85.91(18)
N5AZn2O2
O5BZn1O6E O5BZn1O7C
84.62(17) 85.02(17)
O5BZn1O4D
155.54(16)
O6EZn1O7C
154.44(16)
99.88(19) 127.75(19)
Symmetry code: A = x þ 2, y þ 1/2, z þ 1/2; B = x þ 1, y, z; C = x þ 1, y 1/2, z þ 1/2; D = x þ 1, y þ 1, z þ 1; E = x þ 1, y þ 3/2, z þ 1/2. a
Desolvated 2, obtained by heating 2 at 150 C in a heating chamber under nitrogen (Figure 9, trace b), reversibly incorporates one molecule of DMF at room temperature, after being exposed to neat DMF for 3 h. A comparison of the corresponding XRPD pattern (Figure 9) proves this nicely. An inspection of the CP-MAS 13C NMR spectra (Figure 10) revealed: (i) the presence of NMR singlets related to the presence of solvent molecules in the crystal lattices (i.e., MeOH, 49.0 ppm (trace a); EtOH, 15.0 (CH3) and 58.0 ppm (CH2) (trace b) and DMF, 30.1 (CH3), 35.2 (CH3), and 162.2 ppm (CO) (trace c)); (ii) that regardless of the type of incorporated solvent molecule, only one 13C singlet at 173.0 ppm (i.e., free acid at 167.0 ppm) has been observed for the coordinating carboxylate carbon atoms of terephthalate; (iii) that, the 13C NMR signals assigned to the pyridyl carbon atoms C(3/ 30 ) (111.0/112.0 ppm) and the imidazolyl carbon atoms C(2/20 ) (139.0/142.0 ppm), C(4/40 ) (129.0/130.0 ppm) and C(5/50 ) (118.0/120.0 ppm) are chemically nonequivalent (trace a). This spectroscopic finding is a consequence of the twist of both imidazolyl moieties with respect to the pyridine ring as proved by the corresponding torsion angles found in the crystal structures of 1 (i.e., 151.32 and 11.58) and 2 (i.e., 127.62 and 5.46).
’ CONCLUSIONS The study illustrates that the combination of 2,6-bip and benzencarboxylates allow the construction of intriguing multidimensional zinc network architectures, including a 3D (3,4,6)-connected network of an unprecedented {5.6.7}2{52.6.7.82}2{54.62.73.84.92} topology and the pseudo-supramolecular isomeric pair of 2D (4,4) networks with and without interpenetration, in which the guest solvent exerts a profound influence on controlling the entanglement. The semirigid nature of bip allows a certain degree of flexibility in CN bond rotation, together with the ZnN bond rotations, leading to diverse multidimensional framework topologies. The pseudo-supramolecular isomeric pair shows reversible solvent incorporation properties. ’ EXPERIMENTAL SECTION General Information. All manipulations were performed under a dry nitrogen atmosphere using standard Schlenk techniques. Solvents were dried with standard procedures. Starting chemicals were purchased from commercial source and used as received. 2,6-Bis(imidazol1-yl)pyridine was prepared according to the literature procedure.22 Elemental analyses were performed on a Thermo Flash 2000 CHN-O elemental analyzer. TG analyses were performed with a Mettler Toledo Stare System TGA/SDTA 851e Module. Samples (510 mg) were placed in an alumina sample pan and runs were carried out at a standard heating rate of 10 C/min from 25 to 600 C under a nitrogen flow (60 mL/min). CP-MAS 13C{1H} NMR spectra were acquired on a Bruker DRX-400 spectrometer, equipped with a 4 mm BB CP-MAS probe, at a working frequency of 100.62 MHz and sample spinning rates that varied from 8 to 10 kHz. XRPD spectra were acquired with a PANalytical X’PERT PRO powder diffractometer, employing CuKR radiation (λ = 1.54187 Å) and a parabolic MPD-mirror. Thermodiffraction studies were carried out under nitrogen in an Anton Paar (HTK 1200) high temperature heating chamber in a temperature range from 25 to 600 C and a heating rate of 10 C/min. All XRPD spectra were acquired in a 2θ range from 4 to 80 with a step size of 0.0263 and a counting time of 49.9 s. Synthesis of [Zn(1,4-bdc)(2,6-bip) 3 2H2O]n (1). To a mixture of Zn(NO3)2 3 6H2O (0.704 g, 2.37 mmol), 2,6-bip (0.500 g, 2.37 mmol), and terephthalic acid (0.393 g, 2.37 mmol) in H2O (10 mL) in a 100 mL stainless reactor with Teflon linear was added triethylamine until pH 79. The resulting reaction mixture was heated up to 140 C in 12 h, maintaining it at the latter temperature for 72 h. Afterward, the reaction mixture was allowed to cool down to room temperature at a rate of 8.33 οC/h. Colorless crystals were separated by filtration, washed with deionized water, dry MeOH, DMF, and dried in air. Yield: 0.74 g, 67%. Anal. Calcd for C19H13N5O4Zn 3 2H2O: C, 47.86; H, 3.59; N, 14.68. Found: C, 48.33; H, 3.33; N, 14.41. IR (KBr/pellet cm1): 3402 (w), 3140 (w), 3097 (w), 2374 (w), 1579 (ms), 1491 (ms), 1463 (ms), 1379 (ms), 1287 (ms), 1252 (ms), 1111 (w), 1068 (ms), 1010 (ms), 940 (w), 832 (ms), 763 (ms), 651 (ms), 571 (w), 544 (w), 513 (w), 424 (w). Synthesis of [Zn(1,4-bdc)(2,6-bip) 3 DMF]n (2). A mixture of Zn(NO3)2 3 6H2O (0.202 g, 0.679 mmol), 2,6-bis(imidazol-1yl)pyridine (0.143 g, 0.679 mmol), and terephthalic acid (0.112 g, 0.679 mmol) in DMF (10 mL) was placed in a 100 mL stainless reactor with Teflon linear and heated to 140 C in 24 h. Then it was held at the temperature for 72 h and allowed to cool to room temperature at the rate of 4.16 οC/h. Pale-yellow crystals were separated by filtration; washed with deionized water, dry MeOH, and DMF; and dried in air. Yield: 0.32 g, 92%. Anal. Calcd for C19H13N5O4Zn 3 C3H7NO: C, 51.42; H, 3.92; N, 16.35. Found: C, 51.21; H, 3.47; N, 16.77. IR (KBr/pellet, cm1): 3143 (w), 3098 (w), 1679 (vs), 1598 (vs), 1501 (vs), 1463 (ms), 1389 (ms), 1354 (vs), 1323 (ms), 1288 (w), 1246 (w), 1234 (w), 1184 (w), 1142 1235
dx.doi.org/10.1021/cg101453m |Cryst. Growth Des. 2011, 11, 1230–1237
Crystal Growth & Design (w), 1090 (vs), 1003 (ms), 968 (ms), 944 (ms), 820 (vs), 742 (vs), 652 (vs), 578 (vs), 524 (vs), 495(vs). Synthesis of 3. To a mixture of Zn(NO3)2 3 6H2O (0.845 g, 2.84 mmol), 2,6-bip (0.60 g, 2.84 mmol), and benzene-1,3,5-tricarboxylic acid (0.596 g, 2.84 mmol) in H2O (30 mL) in a 100 mL stainless reactor with Teflon linear was added triethylamine until pH 79. The resultant reaction mixture was then heated to 140 C in 24 h. Then it was hold at the latter temperature for 72 h. Afterward, the reaction solution was allowed to cool down to room temperature at the rate of 4.16 οC/h. Colorless crystals were separated by filtration, washed with deionized water, dry MeOH, DMF and dried in air. Yield: 1.12 g, 68%. Anal. Calcd for C20H12N5O7Zn2 3 H2O: C, 41.19; H, 2.41; N, 12.00. Found: C, 40.74; H, 2.29; N, 12.29. IR (KBr/pellet, cm1): 3516 (w), 3399 (w), 3156 (w), 3129 (w), 2374 (w), 2046 (w), 1727 (ms), 1698 (ms), 1624 (vs), 1582 (vs), 1496 (vs), 1464 (ms), 1385 (w), 1344 (ms), 1284 (ms), 1229 (ms), 1068 (ms), 1007 (w), 968 (w), 945 (w), 805 (w), 740 (ms), 654 (ms). X-ray Diffraction Studies. Reflection data were collected on a Bruker APEX II equipped with a CCD area detector and a graphite monochromator utilizing MoKR radiation (λ = 0.71073 Å) at 150(2) K. The unit cell parameters were obtained by least-squares refinement. The data were integrated via SAINT.56 Lorentz and polarization effect and multiscan absorption corrections were applied with SADABS.57 The structures were solved by direct methods and refined by full-matrix leastsquares methods against F2 with SHELXTL.58 All non-H atoms were refined anisotropically. All H-atoms, except those of water, were fixed at calculated positions and refined with the use of a riding model. H-atoms of the water molecules were located from difference electron density map and not refined. Crystallographic data are listed in Table 1. CCDC797574 (1), 797575 (2), and 797576 (3) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www. ccdc.cam.ac.uk/data_request/cif. Selected bond distances and angles of 13 are listed in Tables 2 and 3.
’ ASSOCIATED CONTENT
bS
Supporting Information. Full crystallographic data for all the structures are provided as a CIF file; table of hydrogen bonds for 2, TG-analyses for 13, TG-analyses and XRPD spectra for the Zn-CPs containing MeOH and EtOH instead of H2O. This material is available free of charge via the Internet at http://pubs.acs.org/.
’ AUTHOR INFORMATION Corresponding Author
*Tel: þ886 4 7232105, ext. 3523 (H.M.L.); þ39 055 5225284 (W.O.). E-mail:
[email protected] (H.M.L.); werner.
[email protected] (W.O.). Fax: þ886 4 7211190 (H.M. L); þ39 055 5225203 (W.O.).
’ ACKNOWLEDGMENT We are grateful to the National Science Council of Taiwan for financial support of this work. We also thank the National Center for High-performance Computing of Taiwan for computing time and financial support of the Conquest software. ’ REFERENCES (1) Proserpio, D. M.; Hoffmann, R.; Preuss, P. J. Am. Chem. Soc. 1994, 116, 9634. (2) Miller, J. S. Adv. Mater. 2001, 13, 525.
ARTICLE
(3) Janiak, C. Dalton Trans. 2003, 2781. (4) Kitagawa, S.; Kitaura, R.; Noro, S. i. Angew. Chem., Int. Ed. 2004, 43, 2334. (5) Czaja, A. U.; Trukhan, N.; Muller, U. Chem. Soc. Rev. 2009, 38, 1284. (6) Rowsell, J. L. C.; Yaghi, O. M. Angew. Chem., Int. Ed. 2005, 44, 4670. (7) Kitaura, R.; Seki, K.; Akiyama, G.; Kitagawa, S. Angew. Chem., Int. Ed. 2003, 42, 428. (8) Seo, J. S.; Whang, D.; Lee, H.; Jun, S. I.; Oh, J.; Jeon, Y. J.; Kim, K. Nature 2000, 404, 982. (9) Lee, J.; Farha, O. K.; Roberts, J.; Scheidt, K. A.; Nguyen, S. T.; Hupp, J. T. Chem. Soc. Rev. 2009, 38, 1450. (10) Horcajada, P.; Serre, C.; Maurin, G.; Ramsahye, N. A.; Balas, F.; Vallet-Regí, M. a.; Sebban, M.; Taulelle, F.; Ferey, G. J. Am. Chem. Soc. 2008, 130, 6774. (11) Horcajada, P.; Serre, C.; Vallet-Regí, M.; Sebban, M.; Taulelle, F.; Ferey, G. Angew. Chem., Int. Ed. 2006, 45, 5974. (12) Meilikhov, M.; Yusenko, K.; Esken, D.; Turner, S.; Van Tendeloo, G.; Fischer, R. A. Eur. J. Inorg. Chem. 2010, 2010, 3701. (13) Batten, S. R.; Robson, R. Angew. Chem., Int. Ed. 1998, 37, 1461. (14) Batten, S. R. CrystEngComm 2001, 3, 67. (15) Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. Rev. 2003, 246, 247. (16) Carlucci, L.; Ciani, G.; Proserpio, D. M. CrystEngComm 2003, 5, 269. (17) Biradha, K.; Sarkar, M.; Rajput, L. Chem. Commun. 2006, 4169. (18) Zaworotko, M. J. Cryst. Growth Des. 2006, 7, 4. (19) Eddaoudi, M.; Moler, D. B.; Li, H.; Chen, B.; Reineke, T. M.; O’Keeffe, M.; Yaghi, O. M. Acc. Chem. Res. 2001, 34, 319. (20) Eddaoudi, M.; Li, H.; Reineke, T.; Fehr, M.; Kelley, D.; Groy, T.; Yaghi, O. M. Top. Catal. 1999, 9, 105. (21) Liu, T.-F.; Lu, J.; Cao, R. CrystEngComm 2010, 660. (22) Chen, C.-Y.; Cheng, P.-Y.; Wu, H.-H.; Lee, H. M. Inorg. Chem. 2007, 46, 5691. (23) Yamada, K.; Tanaka, H.; Yagishita, S.; Adachi, K.; Uemura, T.; Kitagawa, S.; Kawata, S. Inorg. Chem. 2006, 45, 4322. (24) Han, L.; Zhou, Y.; Zhao, W.-N. Cryst. Growth Des. 2008, 8, 2052. (25) Moulton, B.; Zaworotko, M. J. Chem. Rev. 2001, 101, 1629. (26) Zhang, J.-P.; Huang, X.-C.; Chen, X.-M. Chem. Soc. Rev. 2009, 38, 2385. (27) Gao, E.-Q.; Bai, S.-Q.; Wang, Z.-M.; Yan, C.-H. Dalton Trans. 2003, 1759. (28) Dai, J. C.; Wu, X. T.; Hu, S. M.; Fu, Z. Y.; Zhang, J. J.; Du, W. X.; Zhang, H. H.; Sun, R. Q. Eur. J. Inorg. Chem. 2004, 2004, 2096. (29) Du, M.; Jiang, X.-J.; Zhao, X.-J. Chem. Commun. 2005, 5521. (30) Gong, Y.-Q.; Chen, J.-T.; Yuan, D.-Q.; Wu, M.-Y.; Huang, Y.-G.; Jiang, F.-L.; Hong, M.-C. Inorg. Chim. Acta 2007, 360, 2207. (31) Liu, G.-X.; Zhu, K.; Chen, H.; Huang, R.-Y.; Ren, X.-M. CrystEngComm 2008, 10, 1527. (32) Jiang, X.-J.; Guo, J.-H.; Du, M.; Li, J.-S. Polyhedron 2009, 28, 3759. (33) Zhang, M.-L.; Li, D.-S.; Wang, J.-J.; Fu, F.; Du, M.; Zou, K.; Gao, X.-M. Dalton Trans. 2009, 5355. (34) Thirumurugan, A.; Cheetham, A. K. Eur. J. Inorg. Chem. 2010, 2010, 3823. (35) Spek, A. L. J. Appl. Crystallogr. 2003, 28, 7. (36) Aakeroy, C. B.; Champness, N. R.; Janiak, C. CrystEngComm 2010, 12, 22. (37) Adarsh, N. N.; Kumar, D. K.; Dastidar, P. CrystEngComm 2008, 10, 1565. (38) Ghosh, S. K.; Kitagawa, S. CrystEngComm 2008, 10, 1739. (39) Subramanian, S.; Zaworotko, M. J. Angew. Chem., Int. Ed. 1995, 34, 2127. (40) Gable, R. W.; Hoskins, B. F.; Robson, R. J. Chem. Soc., Chem. Commun. 1990, 1677. 1236
dx.doi.org/10.1021/cg101453m |Cryst. Growth Des. 2011, 11, 1230–1237
Crystal Growth & Design
ARTICLE
(41) Zhang, W.-H.; Wang, Y.-Y.; Lermontova, E. K.; Yang, G.-P.; Liu, B.; Jin, J.-C.; Dong, Z.; Shi, Q.-Z. Cryst. Growth Des. 2009, 10, 76. (42) Liu, D.; Ren, Z.-G.; Li, H.-X.; Chen, Y.; Wang, J.; Zhang, Y.; Lang, J.-P. CrystEngComm 2010, 12, 1912. (43) Yu, F.; Kong, X.-J.; Zheng, Y.-Y.; Ren, Y.-P.; Long, L.-S.; Huang, R.-B.; Zheng, L.-S. Dalton Trans. 2009, 9503. (44) Zhao, X.; He, H.; Hu, T.; Dai, F.; Sun, D. Inorg. Chem. 2009, 48, 8057. (45) Zhou, D.-S.; Wang, F.-K.; Yang, S.-Y.; Xie, Z.-X.; Huang, R.-B. CrystEngComm 2009, 11, 2548. (46) Bourne, S. A.; Lu, J.; Mondal, A.; Moulton, B.; Zaworotko, M. J. Angew. Chem., Int. Ed. 2001, 40, 2111. (47) Eddaoudi, M.; Li, H.; Yaghi, O. M. J. Am. Chem. Soc. 2000, 122, 1391. (48) Wu, M.; Jiang, F.; Wei, W.; Gao, Q.; Huang, Y.; Chen, L.; Hong, M. Cryst. Growth & Des. 2009, 9, 2559. (49) Gadzikwa, T.; Zeng, B.-S.; Hupp, J. T.; Nguyen, S. T. Chem. Commun. 2008, 3672. (50) Zhang, E.; Hou, H.; Meng, X.; Liu, Y.; Liu, Y.; Fan, Y. Cryst. Growth & Des. 2008, 9, 903. (51) Ma, B.-Q.; Mulfort, K. L.; Hupp, J. T. Inorg. Chem. 2005, 44, 4912. (52) Xu, G.-J.; Zhao, Y.-H.; Shao, K.-Z.; Lan, Y.-Q.; Wang, X.-L.; Su, Z.-M.; Yan, L.-K. J. Mol. Struct. 2010, 983, 93. (53) Blatov, V. A.; Shevchenko, A. P.; Serezhkin, V. N. J. Appl. Crystallogr. 2000, 33, 1193. (54) Blatov, V. A.; O’Keeffe, M.; Proserpio, D. M. CrystEngComm 2010, 12, 44. (55) Huang, F.-P.; Tian, J.-L.; Li, D.-D.; Chen, G.-J.; Gu, W.; Yan, S.-P.; Liu, X.; Liao, D.-Z.; Cheng, P. CrystEngComm 2010, 12, 395. (56) SAINT; Bruker AXS: Madison, WI, 2007. (57) Sheldrick, G. M. SADABS; University of G€ottingen: Germany, 1996. (58) Sheldrick, G. Acta Crystallogr., Sect. A 2008, 64, 112.
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