Article pubs.acs.org/crystal
A Family of Capsule-Based Coordination Polymers Constructed from a New Tetrakis(1,2,4-triazol-ylmethyl)resorcin[4]arene Cavitand and Varied Dicarboxylates for Selective Metal-Ion Exchange and Luminescent Properties Yu-Jing Hu,† Jin Yang,*,† Ying-Ying Liu,† Shuyan Song,*,‡ and Jian-Fang Ma*,† †
Key Laboratory of Polyoxometalate Science, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China ‡ State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China S Supporting Information *
ABSTRACT: A series of novel capsule-based coordination polymers (CPs), namely, [Cd(TTR4A)(L1)]·2.5H2O (1), [Cd(TTR4A)(L2)]·2DMF·2H2O (2), [Cd(TTR4A)(L3)]·2DMF·1.5H2O (3), [Cd(TTR4A)(L4)]·1.5H2O (4), and [Zn(TTR4A)(L1)]·DMF·H2O (5), have been synthesized via the reaction of a bowl-like tetrakis(1,2,4-triazol-ylmethylresorcin[4]arene (TTR4A) ligand with d10 metal salts in the presence of varied dicarboxylates (H2L1 = fumaric acid, H2L2 = 1,3-benzenedicarboxylic acid, H2L3 = 5-hydroxy-1,3-benzenedicarboxylic acid, H2L4 = biphenylethene-4,4′-dicarboxylic acid, and DMF = N,N-dimethylformamide). CPs 1−3 show rare two-dimensional (2D) capsulebased network structures. In 1−3, two TTR4A bowls share two Cd(II) cations to give a capsule, which is further extended by the dicarboxylates into 2D networks. CP 4 features a fascinating three-dimensional 3-connected framework structure constructed from bowl-like [Cd2TTR4A] units and L4 anions. In 5, each TTR4A coordinates with two Zn(II) cations by using two 1,2,4-triazole groups to generate a capsule, which is further connected by L1 ligands to afford a 2D network structure. Significantly, solid-state emissions and temperature variable luminescence were studied for 1−4. In particular, the remarkable metal-ion exchange property of CP 1 was investigated.
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INTRODUCTION Over the past few decades, coordination polymers (CPs) have increasingly attracted research interest owing to their fascinating motifs and promising potentials in applications such as ion-exchange, gas adsorption, luminescence, sensing, catalysis, and drug delivery.1−18 The structural diversity and versatility are the striking features of CPs, which are mainly derived from the variable coordination modes of the central metal cations and organic linkers.19−27 One of the particular notes is the selection of the organic ligand during the assembly of CPs, which plays a significant role in the final structural features and properties of CPs.28−34 In this context, calixarenes, as a special class of organic ligands along with cyclodextrins, crown-ethers, cryptands, and curcurbiturils, have been actively studied due to their complexing abilities, conformational flexibility, and reactivity.35−41 It is well-known that the calixarenes can be well modified on the body and/or rims with a large variety of substituents, which makes them very versatile ligands.42−44 In this regard, resorcin[4]arenes, as a member of the calixarenes ligands, are especially attractive because of their variable cavity on size, shape, and rigidity adjusted by different functionalized groups.45−47 Nevertheless, © XXXX American Chemical Society
studies engaged in functionalized resorcin[4]arenes as organic linkers for constructing CPs still remain quite rare.48−54 Very recently, our investigation on the coordination chemistry of modified resorcin[4]arenes has successfully resulted in several series of examples featuring charming motifs and properties through the introduction of functionalized tetra- and octacarboxylate groups et al.55−60 In contrast, the triazole functionalized resorcin[4]arenes have not been explored before, although many typical N-containing bridging ligands, such as poly(imidazole) and poly(triazole), have been widely utilized for constructing CPs.61−63 This prompted us to conduct a follow-up investigation on the newly functionalized resorcin[4]arenes with triazole substituents. With the aim to construct resorcin[4]arene-based CPs featuring fascinating structures and properties, we designed a new tetrakis(1,2,4-triazol-ylmethyl)resorcin[4]arene (TTR4A) ligand (Scheme 1). It can be envisaged that the introduction of 1,2,4-triazole functions into the upper-rims of resorcin[4]arene would give rise to structural Received: April 4, 2015 Revised: May 22, 2015
A
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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Scheme 1. Synthetic Route for the TTR4A Ligand
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versatility and diversity of CPs. In the case of TTR4A, the upper rims are modified by four 1,2,4-triazole groups to provide various potential coordination modes and different conformational behaviors. On the other hand, the cavitand of TTR4A, as a capsular subunit, displays a bowl-shaped cavity, which will be beneficial for the assembly of capsule-based CPs. On the other hand, much attention has been paid in recent research of CPs to their postsynthetic modifications (PSMs).64,65 The PSM approach is a powerful and versatile method for producing new analogues from their parent CPs. Particularly, a CP that is not synthesized by conventional methods could be occasionally produced by utilizing the PSM approach.66−68 However, it is very hard to retain the crystalline or intergrity of the framework during the PSMs.69,70 It is well-known that the d10 metal ions such Cd(II) and Zn(II) can be coordinated by ligands in diverse coordination spheres, yielding highly luminescent CPs with novel network structures.34 Moreover, dicarboxylates with different spacer shapes and lengths play an important role in adjusting the unique motifs and useful properties of CPs. For example, both fumaric acid (H2L1) and biphenylethene-4,4′-dicarboxylic acid (H2L4) are rigid dicarboxylic acids, but they possess entirely different spacer lengths, which is likely to result in the structure difference of CPs. In this work, we present the syntheses, crystal structures, and physical properties of five new capsule-based CPs derived from the bowl-like TTR4A ligand and different dicarboxylates, namely, [Cd(TTR4A)(L1)]·2.5H2O (1), [Cd(TTR4A)(L2)]·2DMF·2H2O (2), [Cd(TTR4A)(L3)]·2DMF· 1.5H2O (3), [Cd(TTR4A)(L4)]·1.5H2O (4), and [Zn(TTR4A)(L1)]·DMF·H2O (5) (H2L2 = 1,3-benzenedicarboxylic acid, H2L3 = 5-hydroxy-1,3-benzenedicarboxylic acid, and DMF = N,N-dimethylformamide). The temperature variable luminescent properties for 2−4 were investigated. Moreover, the remarkable metal-ion exchange behavior for 1 was also studied.
EXPERIMENTAL SECTION
Reagents and Instruments. All chemical reagents and solvents were commercially available. A PerkinElmer 240C elemental analyzer was used to determine the C, H, and N elemental analyses. FT-IR spectra were measured on a Mattson Alpha Centauri spectrometer. Inductively compled plasma (ICP) analyses were conducted on a Leeman Laboratories Prodigy inductively coupled plasma-optical atomic emission spectrometer (ICP-AES). The emission/excitation spectra in the solid-state were collected with a FLSP920 Edinburgh fluorescence spectrometer. 1H NMR spectroscopy was recorded at 25 °C on a Varian 500 MHz. Mass spectrum was recorded on a BRUKER AutoflexIII Smartbeam MS-spectrometer. Synthesis of Tetrakis(1,2,4-triazol-ylmethyl)resorcin[4]arene (TTR4A). A mixture of paraldehyde (3.53 g, 80 mmol), 2,6dihydroxytoluene (10.28 g, 80 mmol), 37% aqueous HCl (50 mL), water (100 mL), and ethanol (100 mL) was heated in a water bath for 16 h. The achieved yellow products were washed with cold ethanol− water (1:1) until the washings appeared light yellow to give tetramethyloctol (A) (yield 91%). A mixture of product (A) (10.98 g, 18.3 mmol), CH2ClBr (20 mL), and anhydrous K2CO3 (25.06 g, 181.5 mmol) in DMF (300 mL) was stirred under N2 at 88 °C for 9 h. Then, the mixture was added into 2 N HCl (400 mL), and the solid formed was filtered. The tetramethylresorc[4]arene (B) was purified by silica gel chromatography with CH2Cl2 as the mobile phase (yield 81%). Product (B) (9.63 g, 14.8 mmol), N-bromosuccinimide (NBS) (11.84 g, 66.3 mmol) and a catalytic amount of azodiisobutyronitrile (AIBN) were refluxed in CCl4 (500 mL) for 8 h. The resulting product was filtered, and the precipitate was removed by filtration. Then, the organic layer was washed with water (2 × 100 mL). The crude product was given after evaporation of the solvent, which was recrystallized from CH2Cl2/EtOH to afford tetrabromomethylresorc[4]arene (C) as a yellowish powder (yield 56%). C40H36O8Br4 (Mr = 964.33): 1H NMR (ppm): 1.76 (s, 12H, CH3), 4.14 (s, 4H, CH), 4.42 (s, 8H, CH2Br), 5.29 (s, 8H, OCH2O), 7.26 and 7.27 (s, 4H, Ph). [M + H]+: 964.9181, found: 965.1033. A mixture of NaOH (2.63 g, 66.4 mmol) and 1,2,4-triazole (5.69 g, 83.1 mmol) was dissolved in dry DMF (200 mL). Powder (C) (7.93 g, 8.2 mmol) was poured into the mixture under N2 in water bath for 27 h. Crude product was obtained after the solvent was removed in vacuo, and then water (200 mL) was added. The solid product of TTR4A was filtered, washed by water, and dried (yield 49%). Anal. Calcd for C48H44O8N12 (Mr = 916.94): C, B
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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Table 1. Crystal Data and Structure Refinements for Compounds 1−5 formula Mr crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z Dcalcd [g·cm−3] F(000) R(int) GOF on F2 R1a [I>2σ(I)] wR2b [I>2σ(I)] a
1
2
3
4
5
C52H51CdN12O14.5 1188.45 monoclinic P21/c 22.4474(10) 15.6808(8) 17.7412(14) 90 106.672(7) 90 5982.3(7) 4 1.320 2444 0.0522 1.062 0.0744 0.1947
C62H66CdN14O16 1375.69 monoclinic P21/c 21.6645(7) 16.7527(5) 19.1286(8) 90 112.582(4) 90 6410.2 4 1.425 2848 0.0372 1.040 0.0558 0.1497
C62H64.5CdN14O15.5 1366.18 monoclinic P21/c 21.6201(10) 16.8333(6) 19.1726(8) 90 112.705(5) 90 6436.9(5) 4 1.410 2826 0.0564 1.012 0.0781 0.1970
C40H34CdN6O9.5 863.13 monoclinic C2/c 15.456(2) 33.898(4) 17.976(4) 90 96.038(18) 90 9366(3) 8 1.224 3520 0.0572 0.967 0.0885 0.2303
C55H55ZnN13O13 1171.49 monoclinic P21/c 20.4250(7) 16.7230(9) 16.362(1) 90 102.987(5) 90 5445.8(5) 4 1.429 2440 0.0448 1.032 0.0883 0.2370
R1 = Σ∥Fo| − |Fc∥/Σ|Fo|. bwR2 = {Σ[w(Fo2 − Fc2)2]/Σw(Fo2)2]}1/2.
62.87; H, 4.84; N, 18.33; Found: C, 62.67; H, 4.70; N, 18.41. 1H NMR (ppm): 1.76 (s, 12H, CH3), 2.18 (s, 8H, CH2−Ph), 4.23 (s, 4H, CH), 5.28 (s, 8H, OCH2O), 7.30 and 7.31 (s, 4H, Ph), 8.17 and 8.26 (d, 8H, NCHN). [M + H]+: 917.3483, found: 917.8475. Synthesis of [Cd(TTR4A)(L1)]·2.5H2O (1). A mixture of TTR4A (10.0 mg, 0.01 mmol), Cd(NO3)2·4H2O (14.0 mg, 0.04 mmol), H2L1 (6.0 mg, 0.05 mmol), DMF (3 mL), and water (3 mL) was added into a glass vial (10 mL) and heated at 80 °C for 3 days. Then the glass vial was gradually cooled to the room temperature. The crystals of 1 were achieved in 58% yield based on Cd(II). Anal. Calcd for C52H51O14.5N12Cd (Mr = 1186.45): C, 52.55; H, 4.33; N, 14.15. Found: C, 52.46; H, 4.27; N, 14.22. IR data (KBr, cm−1): 3404(m), 3123(m), 2969(m), 1663(m), 1570(w), 1519(m), 1476(s), 1460(s), 1433(m), 1380(s), 1302(m), 1277(m), 1210(m), 1093(m), 1014(s), 982(s), 948(s), 919(s), 826(w), 804(w), 759(w), 732(w), 673(m), 643(m), 580(m), 501(m). Synthesis of [Cd(TTR4A)(L2)]·2DMF·2H2O (2). Compound 2 was prepared via a synthetic method similar to that of 1. The H2L2 (8.0 mg, 0.048 mmol) was used instead of H2L1, and the reaction temperature was maintained at 90 °C for 4 days. The crystals of 2 were achieved in 42% yield based on Cd(II). Anal. Calcd for C62H66O16N14Cd (Mr = 1375.69): C, 54.13; H, 4.84; N, 14.25. Found: C, 54.01; H, 4.78; N, 14.49. IR data (KBr, cm−1): 3458(m), 3123(s), 2970(s), 1670(s), 1609(m), 1564(m), 1521(m), 1477(m), 1460(m), 1433(m), 1383(m), 1304(s), 1276(m), 1238(m), 1209(m), 1134(m), 1092(m), 1016(m), 983(s), 953(w), 921(m), 827(w), 803(w), 750(m), 721(w), 695(w), 673(m), 643(m), 580(w), 501(w). Synthesis of [Cd(TTR4A)(L3)]·2DMF·1.5H2O (3). Compound 3 was isolated using the same route as that of 1. H2L3 (8 mg, 0.044 mmol) was utilized instead of H2L1 in the mixed water (2 mL) and DMF (4 mL). The crystal products of 3 were isolated in 36% yield based on Cd(II). Anal. Calcd for C62H64.5O15.5N14Cd (Mr = 1366.18): C, 54.51; H, 4.76; N, 14.35; Found: C, 54.32; H, 4.61; N, 14.21. IR data (KBr, cm−1): 3400(m), 3124(m), 2970(m), 1669(s), 1519(m), 1476(m), 1408(m), 1381(m), 1299(m), 1275(m), 1238(m), 1208(m), 1134(m), 1093(m), 1011(m), 982(s), 950(s), 920(m), 786(m), 729(w), 672(m), 643(m), 581(w), 500(w). Synthesis of [Cd(TTR4A)(L4)]·1.5H2O (4). Compound 4 was achieved by using a method similar to that of 1. During the synthesis of 4, H2L4 (12.0 mg, 0.045 mmol) was used instead of H2L1 in the mixed DMF (5 mL) and water (1 mL). Colorless crystal products of 4 were isolated in 37% yield based on Cd(II). Anal. Calcd for C40H34O9.5N6Cd (Mr = 863.13): C, 55.66; H, 3.97; N, 9.74; Found: C, 55.39; H, 3.71; N, 9.39. IR data (KBr, cm−1): 3405(m), 3122(m),
2968(w), 1670(m), 1606(m), 1585(m), 1532(m), 1476(m), 1387(s), 1302(m), 1278(m), 1237(m), 1211(w), 1177(w), 1135(m), 1094(m), 1013(m), 980(m), 950(m), 918(m), 786(m), 709(w), 671(w), 643(m), 580(w), 501(w). Synthesis of [Zn(TTR4A)(L1)]·DMF·H2O (5). Compound 5 was synthesized by using a method similar to that of 1 except that Zn(NO3)2·6H2O was used in place of Cd(NO3)2·4H2O. The crystals of 5 were achieved in 7% yield based on Zn(II). Anal. Calcd for C55H55O13N13Zn (Mr = 1171.49): C, 56.39; H, 4.73; N, 15.54; Found: C, 56.13; H, 4.68; N, 15.61. IR data (KBr, cm−1): 3422(m), 3125(m), 2970(m), 1676(m), 1592(m), 1525(m), 1466(m), 1434(m), 1383(m), 1301(m), 1275(m), 1238(m), 1210(m), 1133(m), 1093(m), 1013(m), 981(s), 948(s), 919(m), 826(w), 802(w), 759(w), 732(w), 673(m), 644(m), 580(w), 501(w). X-ray Crystallography. All single-crystal X-ray diffraction measurements were conducted on a Oxford Diffraction Gemini R Ultra diffractometer using graphite-monochromated Mo−Kα radiation (λ = 0.71073 Å). The structures were solved by direct methods using SHELXS-97.71 Structural refinements were performed by the fullmatrix least-squares method using SHELXL-97 program within WINGX.72 Non-hydrogen atoms were refined with anisotropic temperature parameters, and hydrogen atoms were refined using the riding model. In 1, the disordered atoms (N4 and N4′, N5 and N5′, N6 and N6′, C43 and C43′, and C44 and C44′) of the 1,2,4-triazole group were split over two sites with a total occupancy of 1 for each pair of disordered atoms. In 4, the atoms (C1−C16, O1, O2, O3, and O4) of the H2L4 ligand were disordered by symmetry (their site occupation factors are 0.5 and 0.5, respectively). In 5, the disordered atoms C53 and C53′, and C54, C54′ and C54″ of the DMF molecule were split over two and three sites, respectively (the total occupancy is 1). The disordered atoms (N12 and N12′, and C48 and C48′) of the 1,2,4-triazole group were split over two sites with a total occupancy of 1 for each pair of disordered atoms in 5. A summary of crystallographic data and structure refinements for 1−5 is provided in Table 1. Selected bond lengths and angles for 1−5 are listed in Tables S1−S5.
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RESULTS AND DISCUSSION Structure of [Cd(TTR4A)(L1)]·2.5H2O (1). The asymmetric unit of 1 contains one TTR4A ligand, one Cd(II) cation, one L1 anion, and two and a half water molecules. As illustrated in Figure 1a, each central Cd(II) cation is in a distorted octahedral geometry, completed by three carboxylate oxygen atoms (O1, O3#1, and O4#1) from two distinct L1 anions, and C
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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[Cd(TTR4A)(L2)]·2DMF·2H2O (2) and [Cd(TTR4A)(L3)]· 2DMF·1.5H2O (3) are isostructural and are very similar to that of compound 1 (Figures 2 and 3). In 1−3, three dicarboxylic acids H2L1, H2L2, and H2L3 were used as the linkers, respectively. The two carboxylates of L1 ligand is linear, while the ones of L2 and L3 ligands show V-type angles. It is worth noting that the small variation of the dicarboxylate linkers does not result in structural changes of 2 and 3 in
Figure 1. (a) View of the coordination environment of the Cd(II) cation in 1. Symmetry codes: #1 −x + 1, y − 1/2, −z + 1/2; #2 −x + 1, −y, −z. (b) View of the capsule subunit of 1. (c) View of the capsulebased 2D network structure of 1. The lattice water molecules in the capsules are shown by the red balls.
three nitrogen atoms (N3, N9#2, and N12#2) from two TTR4A ligands. The atoms O1, O3#1, O4#1, and N12#2 constitute the plane of the octahedra, and the atoms N3 and N9#2 are located at the axial positions. Notably, three 1,2,4-triazole groups of each TTR4A ligand coordinate to two Cd(II) cations, while the remaining one is free. Strikingly, in this fashion, two TTR4A bowls form a capsule via sharing two Cd(II) cations, in which one water molecule is included (Figure 1b). Further, adjacent capsules are linked by L1 anions in tridentate modes into an unusual capsule-based 2D network with a Cd···Cd separation of ca. 9.02 Å. Structures of [Cd(TTR4A)(L2)]·2DMF·2H2O (2) and [Cd(TTR4A)(L3)]·2DMF·1.5H2O (3). Single-crystal X-ray diffraction analysis shows that the structures of compounds
Figure 2. (a) View of the coordination environment of the Cd(II) cation in 2. Symmetry codes: #1 −x, y + 1/2, −z + 3/2; #2 −x, −y, −z + 2. (b) View of the capsule subunit of 2. (c) View of the 2D capsulebased network structure of 2. The lattice DMF and water molecules in the capsules are shown by the red balls. D
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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selected as the capsule linker. Fortunately, we achieved a completely different structure of 4. There are half a TTR4A ligand, one and a half L4 anions, and one and a half water molecules in the asymmetric unit of 4. Each central Cd(II) cation is surrounded by four carboxylate oxygen atoms (O1, O2, O5, O6) of two L4 anions, and two nitrogen atoms (N3, N6#1) of the same TTR4A ligand in a distorted octahedral geometry (Figure 4a). Notably, different from those observed
Figure 4. (a) View of the coordination environment of the Cd(II) cation in 4. Symmetry codes: #1 −x + 1, −y, −z + 1; #2 −x + 1, y, −z + 3/2. (b) View of the 1D chain structure of 4 constructed by the bowllike [Cd2TTR4A] units and one type of L4 cations. (c) View of the 3D framework structure of 4. The lattice water molecules are shown by the red balls.
Figure 3. (a) View of the coordination environment of the Cd(II) cation in 3. Symmetry codes: #1 −x + 1, −y, −z + 1; #2 −x + 1, y − 1/ 2, −z + 1/2. (b) View of the capsule subunit of 3. (c) View of the 2D capsule-based network structure of 3. The lattice DMF and water molecules in the capsules are shown by the red balls.
respect to the 2D capsule-based network of 1. In 1−3, two TTR4A ligands share two Cd(II) atoms in the same mode to afford a capsule. Moreover, the Cd(II)···Cd(II) distances separated by the dicarboxylates are also very close. In 2 and 3, the Cd(II)···Cd(II) distance is 9.00 Å, which is very near to that found in 1 (9.02 Å). Structure of [Cd(TTR4A)(L4)]·1.5H2O (4). To further investigate the effect of the spacer length of dicarboxylic acid on the structure, H2L4 ligand with a much longer spacer was
in 1−3, in 4 each TTR4A ligand in tetradentate mode coordinates to two Cd(II) cations by using four 1,2,4-triazole groups, yielding a bowl-like [Cd2TTR4A] unit. It is noteworthy that the two types of L4 anions adopt the same bis-chelating coordination modes, but they act in different roles in the structure of 4. One type of L4 ligand containing O5 and O6 atoms links the adjacent bowl-like [Cd2TTR4A] units to yield a chain structure (Figure 4b). The water molecule is located on E
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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the bottom of the TTR4A bowl. Further, adjacent chains are extended by another type of L4 anions with O1 and O2 atoms into a 3D structure (Figure 4c). In 4, the Cd···Cd distances separated by two types of L4 ligands are 17.428 and 17.552 Å, respectively, which are much longer than those found in 1−3. Topologically, if the Cd(II) cation is regarded as a 3-connected node, and the L4 and TTR4A are considered as two linkers, the 3D framework of 4 can be described as a 3-connected net with (11·102) topology (Figure S1). Structure of [Zn(TTR4A)((L1)](·DMF(·H2O (5). Compound 5 was achieved by using Zn(NO3)·6H2O instead of Cd(NO3)2·4H2O under a synthetic condition similar to 1. The asymmetric unit of 5 is composed of one TTR4A ligand, one L1 anion, one DMF molecule, and one lattice water molecule (Figure 5a). Each Zn(II) cation is surrounded by two carboxylate oxygen atoms (O1 and O4#1) from two different L1 anions, and two nitrogen atoms (N3 and N9#2) from two TTR4A ligands in a tetrahedral geometry. Notably, only two 1,2,4-triazole groups of each TTR4A ligand are involved in coordination with Zn(II) cation in 5, and the remaining two 1,2,4-triazole groups are free. In this fashion, two TTR4A bowls form a capsule via sharing two Zn(II) cations, where the water molecules are included (Figure 5b). Neighboring capsules are further linked by L1 anions into a 2D network (Figure 5c). The Zn···Zn distance separated by the L1 anion in 5 is 8.894 Å, which is near the Cd···Cd distance separated by L1 anion in 1 (9.018 Å). Coordination Modes of the Bowl-Like TTR4A Ligand in 1−5. As illustrated in Scheme 2, the TTR4A ligand adopts three types of coordination modes in compounds 1−5. In 1−3, three 1,2,4-triazole groups of each TTR4A ligand bridge two metals in mode (I), while the remaining 1,2,4-triazole group is free. In 4, four 1,2,4-triazole groups of each TTR4A ligand are involved in coordination with two metals in mode (II). In contrast, in 5 only two 1,2,4-triazole groups of each TTR4A ligand bridge two metals in mode (III), and the rest are free. In compounds 1−3, two TTR4A ligands form the same capsule by sharing the two metals. In 5, two TTR4A ligands share the two metals give a similar capsule. Nevertheless, in 4, all the 1,2,4triazole groups of the TTR4A ligand are involved in coordination with metals, affording a bowl-like unit, rather than the capsule. Noticeably, the coordination modes of the TTR4A ligands act as an important role for the construction of the capsules and capsule-based CPs. Metal-Ion Exchange of 1. After compounds 1−5 were synthesized, a further investigation was performed to determine which types of metal cations can generate similar capsule-based CPs. Under the analogous conditions, divalent Cu(II), Ni(II), and Co(II) cations, showing coordination environments similar to that of Zn(II), were selected to synthesize CPs, but no such products were obtained. It is well-established that the metal-ion exchange is important for the preparation of new CPs that can not be synthesized by direct reactions.73,74 Thereby, in this work we explored the possibility of replacing the Cd(II) cations in CPs 1−4 with Cu(II), Ni(II), and Co(II), by a postsynthetic method. After soaking 1−4 in mother liquor of CuCl2·2H2O, CoCl2·6H2O or NiCl2·2H2O, respectively, for 3 days, only the Cu(II)-exchanged crystals of 1 showed a color change from colorless to green with the original crystal shapes and sizes (named as 1a) (Figure 6). However, the Ni(II)- and Co(II)exchanged crystals of 1 did not display any change in color. Particularly, in all the metal-ion exchange experiments, 2−4 did not display any change in colors. In accordance with the Irving-
Figure 5. (a) View of the coordination environment of the Zn(II) cation in 5. Symmetry codes: #1 −x, −y + 1, −z; #2 −x, y − 1/2, −z − 1/2. (b) View of the capsule subunit of 5. (c) View of the 2D network structure of 5. The lattice DMF and water molecules in the capsules are shown by the red balls.
Williams series concerning the stability of complexes, the Cd(II)-based compounds are relatively stable with respect to the Ni(II)- or Co(II)-based species, while the Cu(II)-based complexes are the most stable.75 As a result, it is possible that the Cd(II)-based CP 1 could be exchanged by the Cu(II) cations. The degree of exchange process during various immersion intervals was further analyzed by ICP (Figure 7). After 5 h, we can clearly see that almost half of the Cd(II) cations in the network were swiftly replaced by Cu(II) cations. After 8 days, almost complete Cd(II) cations on the framework F
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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Scheme 2. Coordination Modes of Bowl-Like TTR4A Ligands in Compounds 1−5
Cu(II) ions on the basis of ICP. After 72 h, the Cu(II)exchanged 1a gradually lose the crystalline. Luminescent Properties. Previous studies have shown that CPs with d10 metals may exhibit excellent photoluminescence properties.77,78 As a result, the solid state luminescent properties of TTR4A and compounds 1−4 were investigated. The free TTR4A ligand shows an emission at 465 nm (λ = 369 nm), and the free H2L1, H2L2, H2L3, and H2L4 reveal emission peaks at 472, 375, 360, and 469 nm, respectively (Figure 8), which are probably ascribed to the
Figure 6. (a) Photographs of crystals of 1 and 1a before and after metal-ion exchange (72 h). (b) Photographs of a single crystal of 1 taken during various immersion intervals after the exchange of Cd(II) with Cu(II) by immersion in mother liquor of CuCl2·2H2O.
Figure 8. Solid-state emission spectra of TTR4A and compounds 1−4.
π* → π or π* → n transitions.79,80 The main emission peaks of 1−4 occur at 457 nm (λex = 376 nm), 460 nm (λex = 360 nm), 475 nm (λex = 376 nm), and 447 nm (λex = 367 nm), respectively. These emissions are attributable to the photoluminescence of ligands. The emission peaks of 2 and 3 are very close to that of the free TTR4A, and their emissions can probably be ascribed to the intraligand emissions. For 1 and 4, their emission peaks are slightly blue-shifted with respect to TTR4A and their corresponding dicarboxylates. The observed blue shift of the emissions is probably caused by the cooperative effects of the TTR4A ligand and the dicarboxylates.81,82 In brief, the emissions of 1−4 arise from the TTR4A ligand and dicarboxylates, or both of them. In order to further investigate the emissions with the temperatures, luminescent intensities in the range of 80−280 K were conducted for 2−4. As illustrated in Figure 9, their luminescent intensities at lower temperatures are highly different from those at room temperature. When the temperature decreases to 80 K, the emission spectra of 2 and 3 tend to split two emission bands. In other words, with increasing
Figure 7. Time-dependent ICP data for the metal compositions during the Cu(II) ion exchange of 1.
of 1 were exchanged with Cu(II) cations (Figure 7). Nevertheless, the metal-ion exchange process was irreversible. The result indicates that 1a is more stabile than the original CP 1.76 It should be pointed out that, through the metal-ion exchange, the crystal quality became poor. Fortunately, within 72 h, the single-crystal X-ray structure can be determined for 1a and reveals that the structure is identical to that of 1 (see Figure S2 and Table S6). The result indicates that the metal-ion exchange is through a single-crystal to single-crystal (SCSC) fashion. In this period, 86.6% of Cd(II) ions were replaced by G
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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Figure 9. (a−c) Luminescent intensity variations for compounds 2a−4c in temperature range of 80−280 K.
Rationally incorporating d10 metal ions (Cd(II) and Zn(II)) as the metal centers in the frameworks offers the possibilities for constructing highly luminescent CPs. The solid-state temperature variable luminescence indicates that the emission intensities of 2−4 increase with the temperature decrease. Of particular note is that CP 1 exhibits remarkable metal-ion exchange from the main network in a SCSC fashion. Further studies on the calixarenes-based molecular cages and CPs are underway in our laboratory.
temperature, the emission intensities decrease, and the two adjacent emissions become more difficult to distinguish. Especially for 2, as the temperature decreases, the emission peak splits became more obvious (Figure 9). Notably, as the temperatures increase from 80 to 280 K, the emission bands for 2 and 3 are slightly blue-shifted, respectively (Figure 9). This phenomenon is probably from the thermally active phononassisted tunneling between the excited states of low-energy site and the excited states of high-energy site.83,84
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CONCLUSIONS In summary, a series of novel capsule-based CPs have been hydrothermally synthesized by using the new bowl-like TTR4A ligand and various dicarboxylates. These CPs show the charming 2D and 3D network structures. Systematic investigation of their structural diversities demonstrates that the bowl-like TTR4A ligands as versatile building blocks can form predictable capsules with metal cations in various coordination fashions. Moreover, the judicious incorporation of different dicarboxylates with various spacers in the assembly process induced the formation of various capsule-based motifs.
ASSOCIATED CONTENT
S Supporting Information *
X-ray crystallographic data in CIF format, selected bond lengths and angles, and drawing of compounds. This material available free of charge via the Internet at The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.cgd.5b00469.
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AUTHOR INFORMATION
Corresponding Authors
*(J.Y.) E-mail:
[email protected] H
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
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*(S.-Y.S.) E-mail:
[email protected]. *(J.-F.M.) E-mail:
[email protected]. Fax: +86-43185098620.
(28) Li, J.-R.; Timmons, D. J.; Zhou, H.-C. J. Am. Chem. Soc. 2009, 131, 6368−6369. (29) Kang, Y.; Wang, F.; Zhang, J.; Bu, X. J. Am. Chem. Soc. 2012, 134, 17881−17884. (30) Zhao, X.; Wong, M.; Mao, C.; Trieu, T. X.; Zhang, J.; Feng, P.; Bu, X. J. Am. Chem. Soc. 2014, 136, 12572−12575. (31) Xiong, Y.; Fan, Y. Z.; Chen, S.; Pan, M.; Jing, J. J.; Su, C. Y. Chem. Commun. 2014, 50, 14631−14634. (32) Kan, W.-Q.; Yang, J.; Liu, Y.-Y.; Ma, J.-F. Inorg. Chem. 2012, 51, 11266−11278. (33) He, Y.-C.; Yang, J.; Yang, G.-C.; Kan, W.-Q.; Ma, J.-F. Chem. Commun. 2012, 48, 7859−7861. (34) Wang, Y.; Yang, J.; Liu, Y.-Y.; Ma, J.-F. Chem. - Eur. J. 2013, 19, 14591−14599. (35) MacGillivray, L. R.; Atwood, J. L. Nature 1997, 389, 469−472. (36) Pochorovski, I.; Milić, J.; Kolarski, D.; Gropp, C.; Schweizer, W. B.; Diederich, F. J. Am. Chem. Soc. 2014, 136, 3852−3858. (37) Kumar, R.; Lee, Y. O.; Bhalla, V.; Kumar, M.; Kim, J. S. Chem. Soc. Rev. 2014, 43, 4824−4870. (38) Kobayashi, K.; Yamanaka, M. Chem. Soc. Rev. 2015, 44, 449− 466. (39) Bi, Y. F.; Du, S. C.; Liao, W. P. Coord. Chem. Rev. 2014, 276, 61−72. (40) Kano, K.; Kondo, M.; Inoue, H.; Kitagishi, H.; Colasson, B.; Reinaud, O. Inorg. Chem. 2011, 50, 6353−6360. (41) Mough, S. T.; Holman, K. T. Chem. Commun. 2008, 1407− 1409. (42) Turunen, L.; Beyeh, N. K.; Pan, F.; Valkonen, A.; Rissanen, K. Chem. Commun. 2014, 50, 15920−15923. (43) Xiong, K.; Wu, M.; Zhang, Q.; Wei, W.; Yang, M.; Jiang, F.; Hong, M. Chem. Commun. 2009, 1840−1842. (44) Xiong, K.; Wang, X.; Jiang, F.; Gai, Y.; Xu, W.; Su, K.; Li, X.; Yuan, D.; Hong, M. Chem. Commun. 2012, 48, 7456−7458. (45) Cholewa, P. P.; Dalgarno, S. J. CrystEngComm 2014, 16, 3655− 3666. (46) Schramm, M. P.; Hooley, R. J.; Rebek, J., Jr. J. Am. Chem. Soc. 2007, 129, 9773−9779. (47) Xiong, K.; Jiang, F.; Gai, Y.; Yuan, D.; Chen, L.; Wu, M.; Su, K.; Hong, M. Chem. Sci. 2012, 3, 2321−2325. (48) Pochorovski, I.; Diederich, F. Acc. Chem. Res. 2014, 47, 2096− 2105. (49) Pochorovski, I.; Milić, J.; Kolarski, D.; Gropp, C.; Schweizer, W. B.; Diederich, F. J. Am. Chem. Soc. 2014, 136, 3852−3858. (50) Chen, C.; Ma, J.-F.; Liu, B.; Yang, J.; Liu, Y.-Y. Cryst. Growth Des. 2011, 11, 4491−4497. (51) Richeter, S.; Rebek, J., Jr. J. Am. Chem. Soc. 2004, 126, 16280− 16281. (52) Busseron, E.; Rebek, J., Jr. Org. Lett. 2010, 12, 4828−4831. (53) Liu, L.-L.; Ren, Z.-G.; Zhu, L.-W.; Wang, H.-F.; Yan, W.-Y.; Lang, J.-P. Cryst. Growth Des. 2011, 11, 3479−3488. (54) Zheng, G.-L.; Li, Y.-Y.; Deng, R.-P.; Song, S.-Y.; Zhang, H.-J. CrystEngComm 2008, 10, 658−660. (55) Lv, L.-L.; Yang, J.; Zhang, H.-M.; Liu, Y.-Y.; Ma, J.-F. Inorg. Chem. 2015, 54, 1744−1755. (56) Zhang, H.; Jiang, W.; Yang, J.; Liu, Y.-Y.; Song, S.-Y.; Ma, J.-F. CrystEngComm 2014, 16, 9939−9946. (57) Li, X.-T.; Li, J.; Li, M.; Liu, Y.-Y.; Song, S.-Y.; Ma, J.-F. CrystEngComm 2014, 16, 9520−9527. (58) Jiang, W.; Zhang, Z.; Yang, J.; Liu, Y.-Y.; Liu, H.-Y.; Ma, J.-F. CrystEngComm 2014, 16, 9638−9644. (59) Liu, Y.-Y.; Chen, C.; Ma, J.-F.; Yang, J. CrystEngComm 2012, 14, 6201−6214. (60) Dong, Y.-B.; Shi, H.-Y.; Yang, Y.; Liu, Y.-Y.; Ma, J.-F. Cryst. Growth Des. 2015, 15, 1546−1551. (61) Yang, J.; Hu, T.; Mak, T. C. W. Cryst. Growth Des. 2014, 14, 2990−3001. (62) Liu, B.; Yang, J.; Yang, G. C.; Ma, J.-F. Inorg. Chem. 2013, 52, 84−94.
Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grant No. 21277022, 21371030, 21301026 and 21471029).
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REFERENCES
(1) Zhou, H.-C.; Long, J. R.; Yaghi, O. M. Chem. Rev. 2012, 112, 673−674. (2) Long, J. R.; Yaghi, O. M. Chem. Soc. Rev. 2009, 38, 1213−1214. (3) Cui, Y.-J.; Yue, Y.-F.; Qian, G.-D.; Chen, B.-L. Chem. Rev. 2012, 112, 1126−1162. (4) Zhou, H.-C.; Kitagawa, S. Chem. Soc. Rev. 2014, 43, 5415−5418. (5) Ma, L.; Abney, C.; Lin, W. B. Chem. Soc. Rev. 2009, 38, 1248− 1256. (6) Sumida, K.; Rogow, D. L.; Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T.-H.; Long, J. R. Chem. Rev. 2012, 112, 724− 781. (7) Zhang, J.-P.; Zhang, Y.-B.; Lin, J.-B.; Chen, X.-M. Chem. Rev. 2012, 112, 1001−1033. (8) Lin, Z.-J.; Lü, J.; Hong, M.-C.; Cao, R. Chem. Soc. Rev. 2014, 43, 5867−5895. (9) Wu, H.; Yang, J.; Su, Z.-M.; Batten, S.-R.; Ma, J.-F. J. Am. Chem. Soc. 2011, 133, 11406−11409. (10) Zhao, D.; Timmons, D. J.; Yuan, D. Q.; Zhou, H.-C. Acc. Chem. Res. 2011, 44, 123−133. (11) Kim, K. Nat. Chem. 2009, 1, 603−604. (12) Yaghi, O. M. Nat. Mater. 2007, 6, 92−93. (13) Meilikhov, M.; Furukawa, S.; Hirai, K.; Fischer, R. A.; Kitagawa, S. Angew. Chem., Int. Ed. 2013, 52, 341−345. (14) Liu, J. W.; Chen, L. F.; Cui, H.; Zhang, J. Y.; Zhang, L.; Su, C.-Y. Chem. Soc. Rev. 2014, 43, 6011−6061. (15) Zhang, Y. B.; Su, J.; Furukawa, H.; Yun, Y. F.; Gándara, F.; Duong, A.; Zou, X. D.; Yaghi, O. M. J. Am. Chem. Soc. 2013, 135, 16336−16339. (16) He, Y. B.; Li, B.; O’Keeffe, M.; Chen, B. L. Chem. Soc. Rev. 2014, 43, 5618−5656. (17) Kreno, L. E.; Leong, K.; Farha, O. K.; Allendorf, M.; Duyne, R. P. V.; Hupp, J. T. Chem. Rev. 2012, 112, 1105−1125. (18) Li, J.; Yang, J.; Liu, Y.-Y.; Ma, J.-F. Chem. - Eur. J. 2015, 21, 4413−4421. (19) Furukawa, H.; Ko, N.; Go, Y. B.; Aratani, N.; Choi, S. B.; Choi, E.; Yazaydin, A. O.; Snurr, R. Q.; O’Keeffe, M.; Kim, J.; Yaghi, O. M. Science 2010, 329, 424−428. (20) Zhang, J. P.; Chen, X. M. J. Am. Chem. Soc. 2009, 131, 5516− 5521. (21) Cohen, S. M. Chem. Rev. 2012, 112, 970−1000. (22) Sumida, K.; Rogow, D. L.; Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T.-H.; Long, J. R. Chem. Rev. 2012, 112, 724−781. (23) Mason, J. A.; Veenstra, M.; Long, J. R. Chem. Sci. 2013, 5, 32− 51. (24) Lu, W. G.; Wei, Z. W.; Gu, Z. Y.; Liu, T. F.; Park, J.; Park, J.; Tian, J.; Zhang, M. W.; Zhang, Q.; Gentle, T.; Bosch, M.; Zhou, H.-C. Chem. Soc. Rev. 2014, 43, 5561−5593. (25) Yang, J.; Ma, J. F.; Batten, S. R. Chem. Commun. 2012, 48, 7899−7912. (26) He, Y.-C.; Yang, J.; Liu, Y.-Y.; Ma, J.-F. Inorg. Chem. 2014, 53, 7527−7533. (27) He, Y.-C.; Yang, J.; Kan, W.-Q.; Zhang, H.-M.; Liu, Y.-Y.; Ma, J.F. J. Mater. Chem. A 2015, 3, 1675−1681. I
DOI: 10.1021/acs.cgd.5b00469 Cryst. Growth Des. XXXX, XXX, XXX−XXX
Crystal Growth & Design
Article
(63) Wu, H.; Liu, H.-Y.; Liu, Y.-Y.; Yang, J.; Liu, B.; Ma, J.-F. Chem. Commun. 2011, 47, 1818−1820. (64) Zhang, H.-M.; Yang, J.; He, Y.-C.; Ma, J.-F. Chem. - Asian J. 2013, 8, 2787−2791. (65) Banerjee, D.; Kim, S. J.; Wu, H. H.; Xu, W. Q.; Borkowski, L. A.; Li, J.; Parise, J. B. Inorg. Chem. 2011, 50, 208−212. (66) Liu, T. F.; Zou, L.; Feng, D.; Chen, Y.-P.; Fordham, S.; Wang, X.; Liu, Y.; Zhou, H.-C. J. Am. Chem. Soc. 2014, 136, 7813−7816. (67) Kim, Y.; Das, S.; Bhattacharya, S.; Hong, S.; Kim, M. G.; Yoon, M.; Natarajan, S.; Kim, K. Chem. - Eur. J. 2012, 18, 16642−16648. (68) Mi, L.; Hou, H.; Song, Z.; Han, H.; Fan, Y. Chem. - Eur. J. 2008, 14, 1814−1821. (69) Park, J.; Chen, Y.-P.; Perry, Z.; Li, J.-R.; Zhou, H.-C. J. Am. Chem. Soc. 2014, 136, 16895−16901. (70) Fei, H.; Cahill, J. F.; Prather, K. A.; Cohen, S. M. Inorg. Chem. 2013, 52, 4011−4016. (71) Sheldrick, G. M. SHELXS-97, Programs for X-ray Crystal Structure Solution; University of Göttingen: Göttingen, Germany, 1997. (72) Farrugia, L. J. WINGX, A Windows Program for Crystal Structure Analysis, University of Glasgow: Glasgow, UK, 1988. (73) Das, S.; Kim, H.; Kim, K. J. Am. Chem. Soc. 2009, 131, 3814− 3815. (74) Yao, R.-X.; Xu, X.; Zhang, X.-M. Chem. Mater. 2012, 24, 303− 310. (75) Irving, H.; Williams, R. J. P. J. Chem. Soc. 1953, 3192−3210. (76) Han, Y.; Li, J.-R.; Xie, Y.-B.; Guo, G. Chem. Soc. Rev. 2014, 43, 5952−5981. (77) Xie, Z. G.; Ma, L. Q.; deKrafft, K. E.; Jin, A.; Lin, W. B. J. Am. Chem. Soc. 2010, 132, 922−923. (78) Nagarkar, S. S.; Joarder, B.; Chaudhari, A. K.; Mukherjee, S.; Ghosh, S. K. Angew. Chem., Int. Ed. 2013, 52, 2881−2885. (79) Yang, J.; Yue, Q.; Li, G.-D.; Cao, J.-J.; Li, G.-H.; Chen, J.-S. Inorg. Chem. 2006, 45, 2857−2865. (80) Thirumurugan, A.; Natarajan, S. J. Chem. Soc., Dalton Trans. 2004, 2923−2928. (81) Bai, H.-Y.; Ma, J.-F.; Yang, J.; Liu, Y.-Y.; Wu, H.; Ma, J.-C. Cryst. Growth Des. 2010, 10, 995−1016. (82) Zhang, Z.; Ma, J.-F.; Liu, Y. Y.; Kan, W. Q.; Yang, J. Cryst. Growth Des. 2013, 13, 4338−4348. (83) Li, B.; Huang, R.-W.; Qin, J.-H.; Zang, S.-Q.; Gao, G.-G.; Hou, H.-W.; Mak, T. C. W. Chem. - Eur. J. 2014, 20, 12416−12420. (84) Wang, X. D.; Wolfbeis, O. S.; Meier, R. J. Chem. Soc. Rev. 2013, 42, 7834−7869.
J
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