Structural Diversity of Four MetalâOrganic Frameworks Based on

Article pubs.acs.org/crystal

Structural Diversity of Four Metal−Organic Frameworks Based on Linear Homo/Heterotrinuclear Nodes with Furan-2,5-dicarboxylic Acid: Crystal Structures and Luminescent and Magnetic Properties Huan-Huan Li, Wei Shi,* Na Xu, Zhen-Jie Zhang, Zheng Niu, Tian Han, and Peng Cheng* Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE), Nankai University, Tianjin, 300071, P. R. China S Supporting Information *

ABSTRACT: Four new homo- and heterometallic metal− organic frameworks (MOFs) based on linear homo/heterotrinuclear nodes, namely, {[NH 2 (CH 3 ) 2 ] 2 [Co 3 (FDA) 4 (CH3OH)2]}n (1), {[NH2(CH3)2]2[Co3(FDA)4]·2DMF}n (2), {[Gd2Co(FDA)4(H2O)4]·2H2O}n (3), and {[Dy2Co(FDA)4(glycol)2]·2H2O}n (4) (H2FDA = furan-2,5-dicarboxylic acid), were obtained under solvothermal conditions and characterized by single crystal X-ray diffraction, magnetic susceptibility, and luminescence measurements. The building blocks of four MOFs are linear trinuclear clusters stabilized by carboxylic groups, but the three-dimensional frameworks are different. MOFs 1 and 2 are both pcu nets with a point symbol of (412.63), whereas MOFs 3 and 4 exhibit 3,10T9 and tfz-d nets with the point symbols of (418.624.83)(43)2 and (43)2(46.618.84), respectively. Magnetic susceptibility measurements indicate that there are antiferromagnetic interactions in 1−3, while 4 displays interesting ferromagnetic interactions between Co(II) and Dy(III) ions. Luminescence investigation of 4 shows intense and characteristic emission bands of Dy(III) ions in the solid state.

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INTRODUCTION Metal−organic frameworks (MOFs) built by coordination bonds between metal ions/clusters and multidentate organic ligands have attracted chemists’ great attention due to not only their intriguing topological structures, but also their potential applications as functional materials in magnetism,1 catalysis,2 gas storage/separation,3,4 sensing,5 ion exchange,6 optics,7 and so on. To get functional MOFs, much effort has been devoted to modify the building blocks and to control them for required products via selecting different organic ligands because the species of metal ions in the periodic table are limited while organic ligands as linkers for the synthesis of MOFs are abundant. The coordination modes of ligands with specific symmetry are key factors to the structures and properties of the final products. For example, in previous work, we have reported a series of porous 4f−3d MOFs based on pyridine-2,6dicarboxylic acid (H2PDA, C2-like symmetry), which exhibited interesting properties such as luminescent probe, radical adsorption, and ferromagnetic interaction.8 Thiophene-2,5dicarboxylic acid (H2TDC) with similar symmetry is another good exobidentate ligands for the construction of porous frameworks, and a lot of functional compounds with H2TDC have been reported.9 As a continuous work to investigate high dimensional frameworks and their intrinsic properties, furan-2,5-dicarboxylic acid (H2FDA) was selected as the organic building block due to its C2-like symmetry, which is similar to that of H2PDA and © 2012 American Chemical Society

H2TDC, and beneficial to generate highly ordered structures. Compared with H2TDC, the oxygen atom of H2FDA is smaller than the sulfur atom and the two carboxylic groups are closer. However, this ligand was received less attention in MOF chemistry.10 The first example of MOF with H2FDA, {[Gd(FDA)1.5(glycol)]·1.5H2O}}n, was reported by us recently.10a It shows three-dimensional porous framework structure based on one-dimensional Gd−COO−Gd chains, exhibiting interesting magnetic and gas adsorption properties. In this contribution, four new homo- and heterometallic MOFs based on linear trinuclear secondary building units (SBUs) were successfully obtained, namely, {[NH2(CH3)2]2[Co3(FDA)4(CH3OH)2]}n (1), {[NH2(CH3)2]2[Co3(FDA)4]·2DMF}n(2), {[Gd2Co(FDA)4(H2O)4]·2H2O}n (3), and {[Dy2Co(FDA)4(glycol)2]·2H2O}n (4). 1−4 were characterized by single crystal X-ray diffraction, infrared spectra (IR), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). In 1 and 2, Co(II) ions are connected by oxygen atoms from μ2-η1:η1 and μ2-η1:η2 carboxylate to form homotrinuclear Co3 SBU, which are further linked by FDA2− to built a 3D pcu net. In 3 and 4, Co(II) and Ln(III) (Ln = Gd, Dy) ions are connected by oxygen atoms from μ2-η1:η1 and μ2-η1:η2 carboxylate of FDA2−, forming a heterotrinuclear Ln−Co−Ln SBU. The heteroReceived: February 9, 2012 Revised: April 6, 2012 Published: April 11, 2012 2602

dx.doi.org/10.1021/cg300196w | Cryst. Growth Des. 2012, 12, 2602−2612

Crystal Growth & Design

Article

Table 1. Crystal Data and Structure Refinement Details for 1−4 formula fw temp (K) cryst system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z Dc (g·cm−3) μ (mm−1) Rint GOF R1 [I > 2α(I)] wR2 [I > 2α(I)] R1 (all data) wR2 (all data) Δρmax (e Å−3) Δρmin (e Å−3)

1

2

3

4

C30H32Co3N2O22 949.37 293(2) monoclinic P21/c 12.7949(4) 8.2582(2) 18.2006(5) 90 107.778(3) 90 1831.29(9) 2 1.722 1.436 0.0368 0.874 0.0345 0.0691 0.0615 0.0725 0.56 −0.51

C34H38Co3 N4O22 1031.47 293(2) monoclinic P21/c 9.2915(4) 15.0734(7) 17.8179(7) 90 97.323(4) 90 2475.12(18) 2 1.384 1.070 0.0412 1.052 0.0863 0.2219 0.1092 0.2407 1.8 −0.96

C24H20CoGd2O26 1097.83 293(2) monoclinic C2/c 10.7608(3) 20.6327(6) 16.8538(7) 90 100.938(3) 90 3674.0(2) 4 1.985 4.109 0.0342 1.176 0.0445 0.1294 0.0610 0.1385 2.51 −0.87

C28H24CoDy2O26 1160.40 293(2) triclinic P1̅ 9.2134(15) 10.1780(8) 11.5556(8) 74.073(7) 79.441(10) 83.594(10) 1022.2(2) 1 1.885 4.108 0.0372 1.077 0.0461 0.1283 0.0574 0.1325 2.767 −0.812

Scheme 1. Synthetic Route of 1−4

spectrum was measured on a Varian Cary Eclipse Fluorescence spectrophotometer. Synthesis of {[NH2(CH3)2]2[Co3(FDA)4(CH3OH)2]}n (1). A mixture of Co(NO3)2·6H2O (0.0582 g, 0.2 mmol), H2FDA (0.0312 g, 0.2 mmol), 4 mL of N,N-dimethylformamide (DMF), and 4 mL of methanol was stirred and then sealed in a 25 mL Teflon-lined autoclave, which was heated at 120 °C for 3 days. After slowly cooling to room temperature over an additional 3 days, purple crystals (59% yield based on Co) were collected after washing with CH3OH and drying in air. IR (KBr, cm−1): 3449 (br), 1585 (s), 1475 (m), 1381 (s), 1221 (m), 1202 (m), 1024 (s), 966 (m), 780 (w), 829 (w), 781 (w). Anal. Calcd for C30H32Co3N2O22: C, 37.95; H, 3.40; N, 2.95. Found: C, 37.69; H, 3.56; N, 3.10. Synthesis of {[NH2(CH3)2]2[Co3(FDA)4]·2DMF}n (2). A mixture of Co(OH)2 (0.0094 g, 0.1 mmol) and H2FDA (0.0156 g, 0.1 mmol), 4 mL of DMF, and 1 mL of H2O was sealed in a Pyrex tube of dimensions 10 mm (outer diameter), 8 mm (inner diameter), and 150 mm (length). Then the tube was placed in the oven, heated at 100 °C for 3 days, and cooled to room temperature over an additional 3 days.

trinuclear SBUs are connected to each other by carboxylic groups forming 1D chains, which are further linked by FDA2− to construct 3D framework. The magnetic properties of 1−4, as well as the luminescent properties of 4, were investigated.

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EXPERIMENTAL SECTION

Materials and Physical Measurements. The ligand H2FDA was purchased from Sigma-Aldrich Co., and the other chemicals purchased were of reagent grade and used without further purification. Elemental analyses (C, H, and N) were performed on a Perkin-Elmer 240 CHN elemental analyzer. IR was recorded in the range 400−4000 cm−1 on a Bruker TENOR 27 spectrophotometer using KBr pellets. PXRD measurements were recorded on a D/Max-2500 X-ray diffractometer using Cu Kα radiation. TGA was performed on a Labsys NETZSCH TG 209 Setaram apparatus with a heating rate of 5 °C/min in the nitrogen atmosphere. Variable-temperature magnetic susceptibilities were performed on a Quantum Design MPMS-7 SQUID magnetometer. Diamagnetic corrections were made with Pascal’s constants for all the constituent atoms and sample holders. The fluorescent 2603



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Figure 1. Crystal structure of 1: (a) ORTEP drawing of the structural unit (thermal ellipsoids are drawn at the 30% probability level; H atoms were omitted for clarity), (b) the coordination environment of Co(II) ions, (c) trinuclear SBU, and (d) linkage modes between trinuclear SBU units. Co is in purple, O in red, N in blue, and C in gray. Deep purple crystals were obtained in 63% yield based on Co after being washed with water/DMF and dried in air. IR (KBr, cm−1): 3424 (br), 1579 (s), 1375 (s), 1021 (m), 788 (m). Anal. Calcd for C34H38Co3N4O22: C, 39.59; H, 3.71; N, 5.43. Found: C, 39.18; H, 4.01; N, 5.46. Synthesis of {[Gd2Co(FDA)4(H2O)4]·2H2O}n (3). A mixture of Co(OH)2 (0.0282 g, 0.3 mmol), Gd(NO3)3·6H2O (0.0451 g, 0.1 mmol), H2FDA (0.0312 g, 0.2 mmol), 6 mL of glycol, and 2 mL of H2O was stirred and then sealed in a 25 mL Teflon-lined autoclave, which was heated at 120 °C for 3 days. After slowly cooling to room temperature over an additional 3 days, salmon pink crystals (59% yield based on Co) were collected after washing with CH3OH and drying in air. IR (KBr, cm−1): 3423 (br), 1589 (s), 1370 (s), 1066 (s), 1016 (s), 967 (m), 874 (m), 832 (m), 784 (m), 621(w). Anal. Calcd for C24H20CoGd2O26: C, 26.26; H, 1.84. Found: C, 26.27; H, 1.82. Synthesis of {[Dy2Co(FDA)4(glycol)2]·2H2O}n (4). The synthetic procedure is similar to that of 3 except that Gd(NO3)3·6H2O was replaced by Dy(NO3)3·6H2O. Pink crystals (49% yield based on Co) were obtained after washing with CH3OH and drying in air. IR (KBr, cm−1): 3386 (br), 1583 (s), 1385 (s), 1227 (s), 1073 (m), 1021 (m), 967 (m), 834 (w), 784 (s). Anal. Calcd for C28H24CoDy2O26: C, 28.98; H, 2.08. Found: C, 29.09; H, 2.46. Crystallographic Studies. Data collections of 1−4 were performed on an Oxford Supernova diffractometer at 293(2) K with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) using the ω-scan technique. The structures were solved by direct method using the program SHELXS-97, and all non-hydrogen atoms were refined anisotropically on F2 by the full-matrix least-squares technique using the SHELXL-97 crystallographic software package.11,12 The selected crystal parameters, data collection, and refinements are summarized in Table 1. The selected bond lengths and angles are listed in Table S1 of the Supporting Information.

MOFs involving linear homo/heterotrinuclear nodes were obtained under different reaction conditions. Reaction of H2FDA with Co(NO3)2·6H2O in DMF/methanol solution at 120 °C afforded purple crystals of 1, which shows a 3D structure with rhomboidal channels along the [0,1,0] direction. Reaction of H2FDA and Co(OH)2 in DMF/H2O at 100 °C produced deep purple prism crystals of 2 with a 3D structure of quadrangle channels along the [0,0,1] direction. When Gd(NO3)3·6H2O was added into the reaction of H2FDA and Co(OH)2 at 120 °C in glycol/H2O, pink prism crystals of 3 were obtained, which exhibit a 3D structure with trigonal channels along the [1,1,0] direction. When Gd(NO3)3·6H2O was replaced with Dy(NO3)3·6H2O under the same reaction conditions, pink prism crystals of 4 were obtained, which have a 3D structure with quadrangle channels along the [0,0,1] direction. The different structures are due to the different connection of the SBUs and will be discussed below. Crystal Structure of {[NH 2 (CH 3 ) 2 ] 2 [Co 3 (FDA) 4 (CH3OH)2]}n (1). X-ray crystallography determination reveals that 1 crystallized in monoclinic space group P21/c. As shown in Figure 1, there are two independent Co(II) ions in the least repeated unit. Both Co1 and Co2 centers are six-coordinated to form distorted octahedral coordination geometry. Co1 coordinated by four oxygens from four different μ2-η1:η1 carboxylates and two oxygens from two different μ2-η1:η2 carboxylate, whereas Co2 coordinates to two oxygens from one μ2-η1:η2 carboxylate, one oxygen from one μ1-η1:η0 carboxylate, two oxygens from two different μ2-η1:η1 carboxylates of four FDA2−, and another oxygen from methanol. There are two different types of FDA2−, which adopt the coordination modes C and G (Scheme 2). Co−O bonds possess an average distance of ∼2.104 Å, which is consistent with the reported values.14 One Co1 is linked with two Co2 via carboxylate bridges to form trinuclear clusters (Co1−Co2 is

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RESULTS AND DISCUSSION Synthesis. Several important factors can influence the final structures of the products, such as solvent, the type of metallic salts, pH, and temperature.13 As shown in Scheme 1, four new 2604



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oxygen from one μ2-η1:η2 carboxylate and three oxygens from three different μ2-η1:η1 carboxylates of four FDA ligands. Notably Co2 also coordinates to two oxygens from two μ2-η1:η2 carboxylates with Co−O bond distances of ∼2.428 Å and finally to form distorted octahedron coordination geometry. There are two types of FDA2−, which adopt the coordination modes E and G (Scheme 2). Co−O bonds possess an average distance of ∼2.085 Å, which is consistent with the reported values.14 One Co1 ion is linked with two Co2 ions via carboxylate bridges to form a trinuclear cluster (Co1−Co2 ∼ 3.371 Å). As shown in Figure 3b, Co3 clusters were connected by eight FDA2− to assemble into a 3D framework (Figure 4). The 3D framework exhibits open channels along the [1,0,0], [0,1,0], and [0,0,1] directions with dimensions ∼5.6 × 5.5 Å2, ∼5.0 × 3.4 Å2, and ∼9.3 × 3.9 Å2, respectively (Figure S2, Supporting Information), and are occupied by disordered DMF molecules and NH2(CH3)2 cations (Figure S3, Supporting Information). PLATON15 analysis revealed that the 3D porous structure was composed of large voids of 2475.1 Å3 that represent 56.3% per unit cell volume without guest molecules/ cations. The major difference between 1 and 2 is the coordination environment of the terminal Co2. In 1, Co2 is six-coordinated with five carboxylate oxygens and one methanol oxygen, while in 2 the coordination environment of Co2 is similar to that in 1 except that two carboxylate oxygens occupied far positions. This minor difference leads to the different three-dimensional frameworks but the same pcu net. Crystal Structure of {[Gd2Co(FDA)4(H2O)4]·2H2O}n (3). Single crystal X-ray analyses reveal that 3 crystallized in the monoclinic space group C2/c. In 3, there are one crystallography independent Co(II) ion and one Gd(III) ion (Figure 5). Each Co(II) ion locates in octahedral coordination geometry finished by four oxygens from four different μ2-η1:η2 carboxylates and another two oxygens from two different μ2η1:η1 carboxylic groups, whereas each Gd(III) ion is ninecoordinated by four oxygens from two μ2-η1:η2 carboxylates, three oxygens from three different μ2-η1:η1 carboxylates of five FDA2−, and another two oxygen from H2O molecules. There are three types of FDA2− with coordination modes of D, G, and I (Scheme 2). The average Co−O bond length is ∼2.076 Å and Gd−O distance is ∼2.442 Å. Therefore, each Gd(III) center has one Co(II) ion as the nearest metal center and each Co(II) centers has two Gd(III) centers in its vicinity, which is consistent with the Co/Gd molar ratio of 2:1. Gd(III) and Co(II) ions are arrayed alternatively and connected by one μ2η1:η2 carboxylate bridge and two μ2-η1:η2 carboxylate bridges to form a Gd2Co trinuclear SBU with Gd−Co distance of ∼3.646 Å, and the Gd−O−Co angles are 105.3(3)° and 101.1(2)°, respectively. Notably, trinuclear SBUs can be linked by two μ2η1:η1 carboxylate bridges to form 1D chains, which are further connected by FDA2− to generate a 3D framework (Figure 6). The 3D framework shows 1D trigonal channels along the [0,0,1] direction, which are occupied by H2O molecules (Figure S4, Supporting Information). PLATON15 analysis revealed that the 3D porous structure is composed of large voids of 3674.0 Å3 that represent 21.9% per unit cell volume when the guest H2O molecules are removed. Crystal Structure of {[Dy2Co(FDA)4(glycol)2]·2H2O}n (4). Compound 4 crystallizes in triclinic space group P1.̅ There are one crystallography independent Co(II) ion and one Dy(III) ion (Figure 7). Each Co(II) center adopts octahedral coordination geometry completed by six oxygens from two μ2-

Scheme 2. Coordination Modes of FDA2−

3.520 Å). As shown in Figure 2, two adjacent trinuclear Co3 cluster were connected by eight FDA2− to assemble into a 3D

Figure 2. The perspective 3D framework of 1: view of the structure along (a) the [1,0,0] direction and (b) the [0,1,0] direction. Color codes: gray for C, blue for Co, red for O.

framework. The 3D framework has 1D rhomboidal channels with dimensions ∼4.9 × 5.0 Å2 along the [0,1,0] direction and is occupied by NH2(CH3)2 cations (Figure S1, Supporting Information). PLATON15 analysis revealed that the 3D porous structure was composed of voids of 1831.3 Å3 that represent 24.8% per unit cell volume without NH2(CH3)2 cations. Crystal Structure of {[NH2(CH3)2]2[Co3(FDA)4]·2DMF}n (2). Compound 2 crystallized in monoclinic space group of P21/c. As shown in Figure 3, there are two independent Co(II) ions in the least repeated unit. the Co1/Co2 center is sixcoordinated to form a distorted octahedral coordination geometry. Co1 coordinates to four oxygens from four different μ2-η1:η1 carboxylates and another two oxygens from two different μ2-η1:η2 carboxylate, whereas Co2 coordinates to one 2605



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Figure 3. Crystal structure of 2: (a) ORTEP drawing of the structural unit (thermal ellipsoids are drawn at the 30% probability level; H atoms were omitted for clarity), (b) the coordination environment of Co(II) ions, (c) trinuclear unit, and (d) linkages between trinuclear units. Co is in pink, O in red, N in blue, and C in gray.

and connected by one μ2-η1η2 carboxylate bridge and two μ2η1η1 carboxylates to form a Dy2Co trinuclear SBU with Co−Dy distance of ∼4.003 Å and the Dy−O−Co angle is 117.6(2)°. Two SBUs are connected by two μ2-η1η1 carboxylate bridges and assembled into a 1D chain. Those 1D chains are stitched to each other by FDA2− with coordination mode D, resulting in infinite 2D nets (Figure 8a), which are further linked by FDA2− with coordination mode G to construct a 3D heterometal− organic framework (Figure 8). The 3D framework exhibits 1D quadrangle channels along the [0,0,1] direction with dimensions ∼6.5 × 5.7 Å2, occupied by H2O molecules (Figure S5, Supporting Information). PLATON analysis revealed that the 3D porous structure contains large voids of 1022.2 Å3 that represent 29.3% per unit cell volume when the guest H2O molecules are removed. For the SBUs of 3 and 4, there are two major differences. First, in 3 Gd(III) and Co(II) ions are connected by one μ2η1η1 carboxylate bridge and two μ2-η1η2 carboxylate bridges to form a Gd2Co trinuclear SBU, whereas in 4 Dy(III) and Co(II) ions are connected by one μ2-η1η2 carboxylate bridge and two μ2-η1η1 carboxylates to form a Dy2Co trinuclear SBU. Second, the Gd(III) center in 3 is nine-coordinated, whereas the Dy(III) center in 4 is eight-coordinated. Such differences result in the 10-connected and 8-connected nodes for the trinuclear SBUs and hence generated different structures. Further research on the nature of these intricate frameworks of 1−4 can be achieved by the application of a topological approach and topology analysis by the freely available computer program TOPOS.16 As shown in Scheme 3, for 1 and 2, if the trinuclear Co3 clusters are considered as uninodal-connected nodes and the FDA2− are considered as bridging spacers, the entire structure can be simplified as a six-connected pcu net (Scheme 3).17 The point symbol for 1 and 2 is (412.63). For 3, if each Gd2Co trinuclear SBU can be considered as a 10-

Figure 4. The 3D framework of 2: (a) view of the structure along (a) the [1,0,0] direction, (b) the [0,1,0] direction, and (c) the [0,0,1] direction.

η1η2 carboxylates and four μ2-η1η1 carboxylates, whereas the Dy(III) center is eight-coordinated with two oxygens from one μ2-η1:η2 carboxylate, four oxygens from four different μ2-η1η1 carboxylates atoms, and two oxygens from a glycol molecule. There are two types of FDA2− with coordination modes of D and G (Scheme 2). The average Co−O bond length is ∼2.104 Å and Dy−O bond distance has an average value of ∼2.372 Å. Therefore, each Dy(III) center has one Co(II) ions as the nearest metal center and each Co(II) center has two Dy(III) centers in its vicinity, which is consistent with the Co/Dy molar ratio of 2:1. Dy(III) and Co(II) ions are arrayed alternatively 2606



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Figure 5. Crystal structure of 3: (a) ORTEP representation of the symmetry expanded structure (30% thermal ellipsoids probability, H atoms were omitted for clarity), (b) the coordination environment of Co(II) and Gd(III) ions, (c) trinuclear SBU, and (d) linkages between trinuclear SBU units. Co is in purple, Gd in green, O in red, and C in gray.

Figure 7. Crystal structure of 4: (a) ORTEP representation of the symmetry expanded structure in 4 (30% thermal ellipsoids probability; H atoms were omitted for clarity), (b) the coordination environment of Co(II) and Dy(III) ions, (c) trinuclear SBU in 3, and (d) linkage modes between trinuclear SBU units. Co is in pink, Dy in green, O in red, and C in gray. Figure 6. The 3D framework of 3: view of the structure along (a) the [0,0,1] direction, (b) the [1,1,0] direction, and (c) the [1,0,0] direction.

point symbol of the topology can be expressed as (418.624.83)(43)2. In 4, if each Dy2Co trinuclear SBU was considered as eight-connected nodes to link with 10 FDA2−, then some of the FDA2− serve as bridging linkers while some as three-connected nodes to link Dy2Co SBUs, and the structure can be considered as a 3,8-connected net named tfz-d.17 This topology is also known in MOF chemistry.19 However, to the best of our knowledge, we are not aware of using the heterometallic clusters as nodes to build the tfz-d framework. The point symbol of the topology can be expressed as (43)2 (46.618.84).

connected node to link with 10 FDA2−. Some of the FDA2− serve as bridging linkers while some as three-connected nodes to link Gd2Co SBUs (Scheme 3). In this way, this structure can be considered as a 3,10-connected net named 3,10T9.17 Acturally, 10-connected nodes are employed in the highdimensional frameworks containing homometallic clusters, whereas the heterometallic examples are rather rare.18 The 2607



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Figure 8. The 3D framework of 4: view of the structure along (a) the [1,0,0] direction, (b) the [0,1,0] direction, (c) the [0,0,1] direction. (d) Spacefilling view of the 3D framework along the [0,0,1] direction.

Scheme 3. Simplified Topological Structure of 1−4a

Figure 9. TGA plots of 1−4.

temperature, due to the strong hydrogen-bonding interaction (O11···O2, 2.663 Å) and the steric hindrance. The TGA of 2 indicates an initial weight loss of 14.6% from 24 to 170 °C, corresponding to the lost of one guest DMF molecule (calcd 14.2%). Compound 2 decomposed vigorously at a temperature higher than 300 °C. The remaining weight of 21.9% may correspond to Co3O4 (calcd 23.3%). Compound 3 lost 3.8% weight in the range of 24−110 °C, corresponding to the release of one lattice water molecule (calcd 3.2%). It began to decompose at a temperature up to 350 °C. For 4, the compound lost 2.8% weight in the range of 24−160 °C, corresponding to the release of the lattice water molecules (calcd 3.1%). Upon further heating, it decomposed gradually. To confirm the phase purity of 1−4, the PXRD patterns have been carried out at room temperature (Figure S6, Supporting Information). The diffraction peaks of the as-synthesized

a

The light green nodes represent the trinuclear SBU in 1 and 2, pink nodes represent the trinuclear SBU in 3, red nodes represent the trinuclear SBU in 4, and the light gray and blue nodes represent FDA2− nodes in 3 and 4.

TGA and PXRD Analyses. TGA of 1−4 was performed in the temperature range of 25−800 °C, as shown in Figure 9. The TGA curve of 1 shows that the compound does not lose any weight until 300 °C, and then it decomposes at higher temperature, suggesting no guest molecules in the lattice, as confirmed by the single crystal X-ray diffraction analysis. The coordinated methanol molecules are difficult to remove at low 2608



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Figure 10. Temperature dependence of χM (■) and χMT (□) for 1 (a) and 2 (b). The solid line denotes the theoretical curve with the best fit. Inset: the Curie−Weiss fit.

Figure 11. Plots of χM (■) and χMT (□) vs T for 3 (a) and 4 (b).

could arise from antiferromagnetic interactions between Co(II) ions and/or zero field splitting (ZFS) effect, expressions 1−4 containing a ZFS parameter (D) for the S = 3/2 system were applied to analyze the magnetic susceptibility data of 1 above 20 K in order to evaluate the magnetic coupling (zJ) between neighboring Co(II) centers.

samples are well in agreement with the simulated data, demonstrating the high phase purity of the compounds. Magnetic Properties. The temperature dependence of magnetic susceptibilities of 1 measured from 300 to 2 K with an applied magnetic field of 1 kOe are shown in Figure 10a. The value of χMT at 300 K is 9.55 cm3 K mol−1, which is much higher than the sum of three isolated spin-only Co(II) ions (5.63 cm3 K mol−1 with g = 2.0 and S = 3/2) but lies in the observed range for hexacoordinated Co(II) complexes. χMT slowly decreases upon cooling to 20 K, which is a typical manner of spin−orbit coupling mainly due to the single-ion behavior of Co(II) ions.20 Below 20 K, χMT has an upturn and reaches a maximum of 7.87 cm3 K mol−1 at 2 K, indicating a ferromagnetic component which is strong enough to compensate for the single-ion behavior resulting from spin− orbit coupling. The magnetic susceptibility data (300−35 K) obey the Curie−Weiss law [χM = C/(T − θ)] with C = 10.35 cm3 mol−1 and θ = −21.75 K (inset of Figure 10a). The negative θ value indicates antiferromagnetic interactions between adjacent Co(II) ions and/or the spin−orbit coupling effect coming from Co(II) ions. As magnetic analysis for hexacoordinated high-spin Co(II) complex is rather complicated due to its spin−orbit coupling, an approximate method is necessary to analyze magnetic interactions between Co(II) ions.21 As mentioned above, two adjacent trinuclear SBUs are separated by long FDA2− ligands. Therefore, the magnetic interactions between adjacent trinuclear SBUs can be ignored, and the interactions can be considered to exist only between two adjacent metal ions bridged by carboxylate groups within the SBUs. As the decrease of χMT in the range of 300−20 K

χ =

Ng 2μB 2 1 + 9e−2D / kBT kBT 4(1 + e−2D / kBT )

Ng 2μB 2 4 + (3kBT /D)(1 − e−2D / kBT ) χ⊥ = kBT 4(1 + e−2D / kBT )

χ′ = χ=

(1)

(2)

χ + 2χ⊥ (3)

3 χ′ ⎛⎜ 2zJ ⎞⎟ 1− χ′ ⎝ Ng 2μB2 ⎠

(4)

In these expressions, N, μB, kB, and g are Avogadro’s number, the Bohr magneton, Boltzmann’s constant, and the Lande factor, respectively. The best fit in the range of 300−20 K was obtained with values of g = 4.61, D = 99.41 cm−1, zJ = −0.28 cm−1, and R = 3.54 × 10−5 (R = ∑[(χMT)obs − (χMT)calc]2/ ∑[(χMT)obs]2). The values match well with those of other Co(II) complexes.22 The negative zJ value suggests weak antiferromagnetic interactions between Co(II) ions. The upturn of χMT below 20 K may attribute to ferromagnetic interactions between the trinuclear SBUs. 2609



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The magnetic behavior of 2 in the form of χMT vs T and χM vs T is depicted in Figure 10b. The value of χMT at 300 K is 9.00 cm3 K mol−1, which is much higher than the theoretical value of 5.63 cm3 K mol−1 for three free spin-only Co(II) ions but lies in the observed range for hexacoordinated Co(II) complexes. Upon cooling, χMT slowly decreases to 7.64 cm3 K mol−1 at 55 K and then increases to 7.91 cm3 K mol−1 at 45 K. Upon further cooling, χMT decreases rapidly to 4.15 cm3 K mol−1 at 2 K. χM−1 versus T plots above 2 K obey the Curie− Weiss law with C = 9.16 cm3 mol−1 and θ = −6.63 K (inset of Figure 10b). The negative θ value suggests antiferromagnetic interactions between Co(II) ions and/or the spin−orbit coupling effect coming from Co(II) ions. To evaluate the magnetic interactions, expressions 1−4 were also applied to fit the data in the temperature range of 300−55 K for 2 and obtained the best-fitting values of g = 4.41, D = 58.87 cm−1, zJ = −0.14 cm−1, and R = 6.48 × 10−6. The values match well with other Co(II) complexes.22 These results reveal weak antiferromagnetic interactions between Co(II) ions in 2. The appearance of a peak at 45 K in the χMT vs T curve indicates the possibility of a weak ferromagnetic interaction arising from the spin-canting.23 The temperature dependence of magnetic susceptibilities for 3 and 4 was measured in the range of 2−300 K under an applied field of 1 kOe (Figure 11). The values of χMT at room temperature for 3 and 4 are 9.08 and 15.47 cm3 K mol−1, respectively, which are slightly higher than the expected values (8.82 and 15.06 cm3 K mol−1) for one spin-only Co(II) ion (S = 3/2) and two Gd(III)/Dy(III) ions. As reported in many of Co(II) complexes,24 the χMT value at room temperature is usually higher than the expected spin-only value due to the orbital contribution of the high-spin Co(II) ions. For 3, upon cooling, the χMT product gradually decreases to 8.74 cm3 K mol−1 at 14 K and then increases to 9.33 cm3 K mol−1 at 2 K. The data above 40 K obey the Curie−Weiss law with C = 5.95 cm3 mol−1 and θ = −0.65 K. The negative θ value suggests antiferromagnetic interactions between Co(II) and Gd(III) ions and/or the spin−orbit coupling effect arising from Co(II) ions. The increase of χMT below 14 K may come from ferromagnetic interactions between Gd(III)−Co(II)−Gd(III) trinuclear units. In the case of 4, as temperature lowered, χMT increases gradually and reaches a maximum value of 19.42 cm3 K mol−1 at 2 K. This feature reveals dominant ferromagnetic interactions between Co(II) and Dy(III) ions. The data (300− 40 K) obey the Curie−Weiss law with C = 15.20 cm3 mol−1 and θ = 6.38 K. The positive θ value further confirms the interesting ferromagnetic interactions between Co(II) and Dy(III) ions in 4. Because Co(II) and Dy(III) ions have intrinsic complicated magnetic characteristics, including the existence of spin−orbit coupling and magnetic anisotropy, it is difficult to quantificationally comment on the magnetic interactions in these two complexes. The ac susceptibility measurement does not show any clear slow relaxation of the magnetization of 4 at low temperature, mainly because the symmetry of the SBU lowers the magnetic anisotropy. Nevertheless, the ferromagnetic interaction between Co(II) and Dy(III) ions in 4 clearly suggests the nonzero spin ground state of the Dy(III)− Co(II)−Dy(III) SBU, which should be a useful magnetic building block to construct molecular magnets or magnetic coolers.25 Luminescent Properties. The solid-state emission spectrum of 4 at room temperature is shown in Figure 12. Excitation of 4 results in luminescence from the lanthanide

Figure 12. Solid-state photoluminescence spectrum of 4.

ions. 4 exhibits three apparent emission bands under the excitation of 293 nm with the maximum emission wavelengths at 478, 574, and 660 nm, respectively, which are ascribed to the characteristic emission 4F9/2 → 6H15/2, 4F9/2→ 6H13/2, and 4 F9/2→ 6H11/2 transitions of Dy(III) ion.26 It is obvious that the intensity of the yellow emission corresponding to 4F9/2→ 6 H13/2 is much stronger than that of the blue one (4F9/2 → 6 H15/2). The luminescence investigations mentioned above suggested that the FDA2− may effectively sensitize the luminescence of Dy(III) ions by UV radiation.

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CONCLUSION In summary, we have successfully synthesized four new MOFs based on linear homo/heterotrinuclear nodes with furan-2,5dicarboxylic acid via solvothermal conditions. Though the building blocks of the four MOFs are all linear trinuclear clusters stabilized by carboxylic groups, the three-dimensional frameworks are different due to the structural nature of the SBUs. Magnetic investigations reveal that antiferromagnetic interactions appears between Co(II) ions in 1 and 2. It is noted that 4 displays interesting ferromagnetic interactions between Co(II) and Dy(III) ions, as well as interesting luminescent properties. This work provides a rational synthetic strategy for the construction of novel homo/heterometallic functional materials with dicarboxylate ligands with special symmetry. Further systematic studies for the design and construction with furan-2,5-dicarboxylic acid are underway in our laboratory.

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ASSOCIATED CONTENT

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AUTHOR INFORMATION

* Supporting Information S

X-ray crystallographic files in CIF format for structures 1−4, Tables S1 and S2, PXRD patterns, and additional figures. This material is available free of charge via the Internet at http:// pubs.acs.org. Corresponding Author

*E-mail: [email protected] (W.S.); [email protected] (P.C.). Notes

The authors declare no competing financial interest. 2610



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(b) Zhao, B.; Cheng, P.; Chen, X. Y.; Cheng, C.; Shi, W.; Liao, D. Z.; Yan, S. P.; Jiang, Z. H. J. Am. Chem. Soc. 2004, 126, 3012−3013. (c) Zhao, B.; Chen, X. Y.; Cheng, P.; Liao, D. Z.; Yan, S. P.; Jiang, Z. H. J. Am. Chem. Soc. 2004, 126, 15394−15395. (d) Zhao, X. Q.; Zhao, B.; Ma, Y.; Shi, W.; Cheng, P.; Jiang, Z. H; Liao, D. Z.; Yan, S. P. Inorg. Chem. 2007, 46, 5832−5834. (e) Zhao, X.-Q.; Zhao, B.; Shi, W.; Cheng, P. Inorg. Chem. 2009, 48, 11048−11057. (f) Zhao, X.-Q.; Zhao, B.; Shi, W.; Cheng, P.; Liao, D.-Z.; Yan, S.-P. Dalton Trans. 2009, 2281−2283. (g) Zhao, X.-Q.; Cui, P.; Zhao, B.; Shi, W.; Cheng, P. Dalton Trans. 2011, 40, 805−819. (h) Zhao, B.; Gao, H.-L.; Chen, X.Y.; Cheng, P.; Shi, W.; Liao, D.-Z.; Yan, S.-P.; Jiang, Z.-H. Chem.−Eur. J. 2006, 12, 149−158. (9) (a) Huang, W.; Wu, D.; Zhou, P.; Yan, W.; Guo, D.; Duan, C.; Meng., Q. Cryst. Growth Des. 2009, 9, 1361−1369. (b) Zhan, C.-H.; Wang, F.; Kang, Y.; Zhang, J. Inorg. Chem. 2012, 51, 523−530. (c) Koh, K.; Wong-Foy, A. G.; Matzger., A. J. J. Am. Chem. Soc. 2010, 132, 15005−15010. (d) Chen, Z.; Zhao, B.; Cheng, P.; Zhao, X.-Q.; Shi, W.; Song., Y. Inorg. Chem. 2009, 48, 3493−3495. (e) Xu, J.; Cheng, J.; Su, W.; Hong, M. Cryst. Growth Des. 2011, 11, 2294−2301. (f) Byrnes, M. J.; Chisholm, M. H. Chem. Commun. 2002, 2040−2041. (g) Brown, D. J.; Chisholm, M. H.; Gribble, C. W. Dalton Trans. 2007, 1793−1801. (h) Takashima, Y.; Bonneau, C.; Furukawa, S.; Kondo, M.; Matsudabc, R.; Kitagawa, S. Chem. Commun. 2010, 46, 4142− 4144. (i) Abourahma, H.; Bodwell, G. J.; Lu, J.; Moulton, B.; Pottie, I. R.; Walsh, R. B.; Zaworotko, M. J. Cryst. Growth Des. 2003, 3, 513− 519. (j) Jia, H.-P.; Li, W.; Ju, Z.-F.; Zhang., J. Eur. J. Inorg. Chem. 2006, 4264−4270. (k) Byrnes, M. J.; Chisholm, M. H.; Clark, R. J. H.; Gallucci, J. C.; Hadad, C. M.; Patmore, N. J. Inorg. Chem. 2004, 43, 6334−6344. (l) Demessence, A.; Rogez, G.; Welter, R.; Rabu., P. Inorg. Chem. 2007, 46, 3423−3425. (m) Rosi, N. L.; Kim, J.; Eddaoudi, M.; Chen, B.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc. 2005, 127, 1504−1518. (n) Zhang, J.; Chen, S.; Wu, T.; Feng, P.; Bu., X. J. Am. Chem. Soc. 2008, 130, 12882−12883. (10) (a) Li, H. H.; Niu, Z.; Han, T.; Zhang, Z. J.; Shi, W.; Cheng, P. Sci. China Chem. 2011, 54, 1423−1429. (b) Nagarkar, S. S.; Chaudhari, A. K.; Ghosh, S. K. Cryst. Growth Des. 2012, 12, 572−576. (11) Sheldrick, G. M. SHELXS 97, Program for the Solution of Crystal Structures; University of Göttingen, Germany, 1997. (12) Sheldrick, G. M. SHELXL 97, Program for the Refinement of Crystal Structures; University of Göttingen, Germany, 1997. (13) Batten, S. R.; Neville, S. M.; Turner, D. R. Coordination Polymers: Design, Analysis and Application; Royal Society of Chemistry, Cambridge, 2008. (14) Lama, P.; Aijaz, A.; Sañudo, E. C.; Bharadwaj, P. K. Cryst. Growth Des. 2010, 10, 283−290. (15) Spek, A. L. Acta Crystallogr., Sect. A: Found. Crystallogr. 1990, 46, C34. (16) (a) Blatov, V. A. Multipurpose crystallochemical analysis with the program package TOPOS. IUCr CompComm Newsletter 7, 4− 38, 2006; available at http://iucrcomputing.ccp14.ac.uk/iucr-top/ comm/ccom/newsletters/2006nov/. (17) (a) O’Keeffe, M.; Peskov, M. A.; Ramsden, S. J.; Yaghi, O. M. Acc. Chem. Res. 2008, 41, 1782−1789. (b) O’Keeffe, M. Reticular Chemistry Structure Resource (http://rcsr.anu.edu.au/). (18) (a) Alexandrov, E. V.; Blatov, V. A.; Kochetkov, A. V.; Proserpio, D. M. CrystEngComm. 2011, 13, 3947−3958. (b) Wang, S.; Xing, H.; Li, Y.; Bai, J.; Pan, Y.; Scheer, M.; You, X. Eur. J. Inorg. Chem. 2006, 3041−3053. (c) Chu, Q.; Liu, G.-X.; Huang, Y.-Q.; Wang, X.-F.; Sun, W.-Y. Dalton Trans. 2007, 4302−4311. (d) Zhou, Q.-Xi; Bai, X.J.; Chen., L.-P. Chin. J. Struct. Chem. 2006, 25, 49−52. (e) Yun, S.-S.; Kim, Y.-P.; Kim, C.-H. J. Coord. Chem. 2003, 56, 363−372. (19) (a) Garibay, S. J.; Stork, J. R.; Wang, Z. Q.; Cohen, S. M.; Telfer, S. G. Chem. Commun. 2007, 4881−4883. (b) Luo, F.; Che, Y.; Zheng, J. Cryst. Growth Des. 2008, 8, 2006−2010. (c) Xu, G. J.; Zhao, Y. H.; Shao, K. Z.; Lan, Y. Q.; Wang, X. L.; Su, Z. M.; Yan, L. K. CrystEngComm 2009, 11, 1842−1848. (d) Davies, R. P.; Less, R. J.; Lickiss, P. D.; Robertson, K.; White, A. J. P. Inorg. Chem. 2008, 47, 9958−9964. (e) Liu, G.-X.; Huang, Y.-Q.; Chu, Q.; Okamura, T.; Sun, W.-Y.; Liang, H.; Ueyama, N. 2008, 8, 3233−3245. (f) Davies, R. P.;

ACKNOWLEDGMENTS We thank the “973 program” (2012CB821702), the NSFC (90922032, 20971073, 21171100 and 21151001), and MOE (20100031110009 and IRT0927) for support.

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REFERENCES

(1) (a) Kahn, O. Molecular maleculor; Wiley−VCH: Weinheim, 1993; Chapter 11. (b) Gatteschi, D.; Sessoli, R.; Villain, J. Molecular Nanomagnets; Oxford University Press: New York, 2006. (2) (a) Hasegawa, S.; Horike, S.; Matsuda, R.; Furukawa, S.; Mochizuki, K.; Kinoshita, Y.; Kitagawa, S. J. Am. Chem. Soc. 2007, 129, 2607−2614. (b) Davis, M. E. Top. Catal. 2003, 25, 3−7. (c) Corma, A.; Garcia, H.; Llabrés i Xamena, F. X. Chem. Rev. 2010, 110, 4606− 4655. (d) Lee, J. Y.; Farha, O. K.; Roberts, J.; Scheidt, K. A.; Nguyen, S. T.; Hupp, J. T. Chem. Soc. Rev. 2009, 38, 1450−1459. (e) Fujita, M.; Kwon, Y. J.; Washizu, S.; Ogura, K. J. Am. Chem. Soc. 1994, 116, 1151−1152. (f) Wu, C. D.; Hu, A.; Zhang, L.; Lin, W. J. Am. Chem. Soc. 2005, 127, 8940−8941. (g) Seo, J. S.; Whang, D.; Lee, H.; Jun, S. I.; Oh, J.; Jeon, Y. J.; Kim, K. Nature 2000, 404, 982−986. (h) Wang, Z. Q.; Cohen, S. M. Chem. Soc. Rev. 2009, 38, 1315−1329. (3) (a) Dincă, M.; Long, J. R. J. Am. Chem. Soc. 2005, 127, 9376− 9377. (b) Murray, L. J.; Dincă, M.; Long, J. R. Chem. Soc. Rev. 2009, 38, 1294−1314. (c) Ma, S.; Zhou, H.-C. J. Am. Chem. Soc. 2006, 128, 11734−11735. (d) Yaghi, O. M.; Li, G.; Li, H. Nature 1995, 378, 703− 706. (e) Matsuda, R.; Kitaura, R.; Kitagawa, S.; Kubota, Y.; Belosludov, R. V.; Kobayashi, T. C.; Sakamoto, H.; Chiba, T.; Takata, M.; Kawazoe, Y.; Mita, Y. Nature 2005, 436, 238−241. (f) Chen, B.; Eddaoudi, M.; Hyde, S. T.; O’Keeffe, M.; Yaghi, O. M. Science 2001, 291, 1021−1023. (g) Kesanli, B.; Cui, Y.; Smith, M.; Bittner, E.; Bockrath, B.; Lin, W. Angew. Chem., Int. Ed. 2004, 44, 72−75. (4) (a) Eddaoudi, M.; Kim, J.; Rosi, N.; Vodak, D.; Wachter, J.; O’Keeffe, M.; Yaghi, O. M. Science 2002, 295, 469−472. (b) Hayashi, H.; Côté, A. P.; Furukawa, H.; O’Keeffe, M.; Yaghi, O. M. Nat. Mater. 2007, 6, 501−506. (c) Demessence, A.; D’Alessandro, D. M.; Foo, M. L.; Long, J. R. J. Am. Chem. Soc. 2009, 131, 8784−8786. (d) Horcajada, P.; Serre, C.; Vallet-Regi, M.; Sebban, M.; Taulelle, F.; Férey, G.. Angew. Chem., Int. Ed. 2006, 45, 5974−5978. (e) Zhao, X. B.; Xiao, B.; Fletcher, A. J.; Thomas, K. M.; Bradshaw, D.; Rosseinsky, M. J. Science 2004, 306, 1012−1015. (f) Li, J.-R.; Kuppler, R. J.; Zhou, H.-C. Chem. Soc. Rev. 2009, 38, 1477−1504. (g) Britt, D.; Tranchemontagne, D.; Yaghi, O. M. Proc. Natl. Acad. Sci. U. S. A. 2008, 105, 11623−11627. (h) Kuppler, R. J.; Timmons, D. J.; Fang, Q. R.; Li, J. R.; Makal, T. A.; Young, M. D.; Yuan, D. Q.; Zhao, D.; Zhuang, W. J.; Zhou, H. C. Coord. Chem. Rev. 2009, 253, 3042−3066. (5) (a) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T. Chem. Soc. Rev. 2009, 38, 1330−1352. (b) Maspoch, D.; Ruiz-Molina, D.; Veciana, J. Chem. Soc. Rev. 2007, 36, 770−818. (c) Suh, M. P.; Cheon, Y. E.; Lee, E. Y. Coord. Chem. Rev. 2008, 252, 1007−1026. (d) Albrecht, M.; Lutz, M.; Spek, A. L.; van Koten, G. Nature 2000, 406, 970−974. (e) Real, J. A.; Andrss, E.; MuToz, M. C.; Julve, M.; Granier, T.; Bousseksou, A.; Varret, F. Science 1995, 268, 265−267. (f) Beauvais, L. G.; Shores, M. P.; Long, J. R. J. Am. Chem. Soc. 2000, 122, 2763−2772. (6) (a) Zhao, J. A.; Mi, L. W.; Hu, J. Y.; Hou, H. W.; Fan, Y. T. J. Am. Chem. Soc. 2008, 130, 15222−15223. (b) Dincă, M.; Long, J. R. J. Am. Chem. Soc. 2007, 129, 11172−11176. (7) (a) Kuppler, R. J.; Timmons, D. J.; Fang, Q. R.; Li, J. R.; Makal, T. A.; Young, M. D; Yuan, D. Q; Zhao, D.; Zhuang, W. J.; Zhou, H. C. Coord. Chem. Rev. 2009, 253, 3042−3066. (b) Meek, S. T.; Greathouse, J. A.; Allendorf, M. D. Adv. Mater. 2011, 23, 249−267. (c) Kuppler, R. J.; Timmons, D. J.; Fang, Q. R.; Li, J. R.; Makal, T. A.; Young, M. D.; Yuan, D. Q.; Zhao, D.; Zhuang, W. J.; Zhou, H. C. Coord. Chem. Rev. 2009, 253, 3042−3066. (d) Chen, B.; Wang, L; Zapata, F.; Qian, G.; Lobkovsky, E. B. J. Am. Chem. Soc. 2008, 130, 6718−6719. (e) Cui, Y.; Yue, Y.; Qian, G.; Chen, B. Chem. Rev. 2012, 112, 1126−1162. (8) Zhao, B.; Cheng, P.; Dai, Y.; Cheng, C.; Liao, D. Z.; Yan, S. P.; Jiang, Z. H.; Wang, G. L. Angew Chem., Int. Ed. 2003, 42, 934−936. 2611



Article

Less, R. J.; Lickiss, P. D.; Robertson, K.; White., A. J. P. Inorg. Chem. 2008, 47, 9958−9964. (20) Sun, H. L.; Wang, Z. M.; Gao, S. Inorg. Chem. 2005, 44, 2169− 2176. (21) (a) Zhang, S. H.; Song, Y.; Liang, H.; Zeng, M. H. CrystEngComm 2009, 11, 865−872. (b) Zeng, M. H.; Yao, M. X.; Liang, H.; Zhang, W. X.; Chen, X. M. Angew Chem. Int. Ed. 2007, 46, 1832−1835. (c) Jia, H. P.; Li, W.; Ju, Z. F.; Zhang, J. Dalton Trans. 2007, 3699−3704. (22) (a) Zhu, Z.; Karasawa, S.; Koga, N. Inorg. Chem. 2005, 44, 6004−6011. (b) Rizzi, A. C.; Brondino, C. D.; Calvo, R.; Baggio, R.; Garland, M. T.; Rapp., R. E. Inorg. Chem. 2003, 42, 4409−4416. (c) Lloret, F.; Julve, M.; Cano, J.; Ruiz-Garcia, R.; Pardo, E. Inorg. Chim. Acta 2008, 361, 3432−3445. (23) Wang, X. T.; Wang, X. H.; Wang, Z. M.; Gao, S. Inorg. Chem. 2009, 48, 1301−1308. (24) (a) Klöwer, F.; Lan, Y.; Nehrkorn, J.; Waldmann, O.; Anson, C. E.; Powell, A. K. Chem.−Eur. J. 2009, 15, 7413−7422. (b) Mondal, K. C.; Kostakis, G. E.; Lan, Y.; Anson, C. E.; Powell, A. K. Inorg. Chem. 2009, 48, 9205−9213. (25) (a) Yamaguchi, T.; Costes, J.-P.; Kishima, Y.; Kojima, M.; Sunatsuki, Y.; Bréfuel, N.; Tuchagues, J.-P.; Vendier, L.; Wernsdorfer, W. Inorg. Chem. 2010, 49, 9125−9135. (b) Yamada, Y.; Tanabe, M.; Miyashita, Y.; Okamoto, K. Polyhedron 2003, 22, 1455−1459. (26) (a) Hua, K. T.; Xu, J.; Quiroz, E. E.; Lopez, S.; Ingram, A. J.; Johnson, V. A.; Tisch, A. R.; de Bettencourt-Dias, A.; Straus, D. A.; Muller, G. Inorg. Chem. 2012, 51, 647−660. (b) Amghouz, Z.; GarcíaGranda, S.; García, J. R. Inorg. Chem. 2011, 51, 1703−1716. (c) Arnaud, N.; Vaquer, E.; Georges, J. Analyst 1998, 123, 261−265.

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