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A new 3D fluorescent lanthanide-organic framework containing helical chains and zigzag layers from mixed carboxylate ligands
Inorganic Chemistry Communications 14 (2011) 68–71
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Inorganic Chemistry Communications j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i n o c h e
A new 3D fluorescent lanthanide-organic framework containing helical chains and zigzag layers from mixed carboxylate ligands Zhi-Gang Gu, Jin-Hao Chen, Yue-Nan Chen, Yin Ying, Hui-Ming Peng, Hong-Yang Jia, Ming-Fang Wang, Shan-Shan Li, Yue-Peng Cai ⁎ School of Chemistry and Environment, Key Lab of Technology on Electrochemical Energy Storage and Power Generation in Guangdong Universities, Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006, PR China
a r t i c l e
i n f o
Article history: Received 30 August 2010 Accepted 27 September 2010 Available online 15 October 2010 Keywords: Lanthanide-organic framework Mixed carboxylate ligands Zigzag layer Race-helical chain Fluorescence
a b s t r a c t A new 3D lanthanide compound [Pr(H2O)(C5HN2O4)(CH3COO)·H2O]n (1) has been hydrothermally synthesized by employing 4,5-imidazoledicarboxylic (H3IDC) and acetic acid mixed ligands and characterized by element analysis, IR spectroscopy and thermal analysis, as well as single-crystal X-ray diffraction. The results show that complex 1 has a 3D (3,4)-connected network structure containing zigzag layers and 1D racehelical chains (P- and M-chains), which denote the first example of lanthanide coordination framework including the mixed ligands of imidazole-4,5-dicarboxlylate and acetate. Moreover, compound 1 displays a strong photoluminescent property and a high thermal stability. © 2010 Elsevier B.V. All rights reserved.
Over the last decade, self-assembly of metal-organic frameworks (MOFs) has been well developed, which has grown into a subject that attracts great attention because of their intriguing aesthetic and topological structures as well as their potential applications in fields such as optics, catalysis, magnetic devices, gas storage, separation and so on [1–4]. MOFs are generally constructed by discrete metal polyhedra or isolated small clusters coordinated to linking organic functional groups which have been widely used in the construction of metal–organic complexes with various dimensional networks and interesting properties [5–7]. During the course of our study, we have reported a series of low dimensional [8–10] and high dimensional [11,12] metal-organic frameworks. As a continuation of the previous work, our goal is to design and synthesize 3D metal-organic frameworks with the interesting topologies containing imidazole-4,5-dicarboxlylatic acid (H3IDC) and other auxiliary carboxylate. Here we report one 3D lanthanide metal-organic framework containing H3IDC and acetic acid, namely [Pr(H2O)(C5H2N2O4) (CH3COO)·H2O]n, which contains helical chains and zigzag layers. The unique structure not only leads to interesting topological arrangements, but also plays an important role in photoluminescent activities. Topological analysis suggests that the complex displays an ins-(3,4)-connected net with race-helical chains and zigzag layers. This complex also demonstrates an intensive photoluminescence and high
⁎ Corresponding author. Tel.: +86 020 39310383; fax: +86 020 39310187. E-mail address: [email protected] (Y.-P. Cai). 1387-7003/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2010.09.033
thermal stability. In this paper, we report its synthesis, crystal structure, thermal gravimetric analysis (TGA) and photoluminescence in details. Imidazole-4,5-dicarboxlylic and acetic acids are chosen as multifunctional ligands, mainly based on the following considerations: (i) as
Fig. 1. The coordination environment of the PrIII ion in 1. Hydrogen atoms have been omitted for clarity. Symmetry codes: (i) 1 + x, y, z; (ii) 1 − x, 1 − y, 1 − z; (iii) −1 + x, y, z; and (iv) −1 + x, 1.5 − y, −0.5 + z.
Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
Scheme 1. Coordination modes of (a) HIDC2− and (b) Ac− in 1.
an aromatic rigid ligand, H3IDC is easy to chelate metal center to form a 2D zigzag layer. (ii) Acetate ligand as non-aromatic has versatile coordination modes and can meet the high coordination number of lanthanide metal ions. (iii) The weak interactions of the mixed ligands may construct interesting helical chains. Compound 1 was synthesized hydrothermally with a mixture of praseodymium oxide, H3IDC, acetic acid and 15 mL water sealed in a 20 mL Teflon-lined stainless-steel autoclave and heated at 160 °C for 90 h [12]. The water molecules in compound 1 are proved by the strong and broad band at 3663 cm− 1, which is ascribed to the stretching vibrations νO–H. The strong bands of the N–H stretching frequencies in 1 are covered by the broad absorption bands of hydrogen bonds, the bands at 3175 cm− 1 may correspond to νN–H. The absorption bands at 1542 and 1389 cm− 1 cm− 1 for 1 correspond to the asymmetric mode
69
νas(COO−) and the symmetric mode νs(COO−) of the carboxylate groups, respectively. The difference of 253 cm− 1 between νas(COO−) and νs(COO−) in 1 indicates that bridging carboxylates are in the exobidentate mode [13], as proved by the X-ray crystal structure analysis. The structure analysis [14] reveals that complex 1 crystallizes in the P21/c space group and exhibits a 3D organic framework constructed from mixed Pr–HIDC2− layers, binuclear Pr linkers and hydrogen-bonded race-helical chains, in which the asymmetric unit includes one Pr(III) ion, one HIDC2−, one CH3COO−, one coordinated water and one lattice water. As shown in Fig. 1, Pr1 ion is nine-coordinated by four oxygen atoms (O1, O4, O5, and O6i) and one nitrogen atom (N1) from three μ3-HIDC2−, three oxygen atoms (O2, O3 and O3i) from two μ2-CH3COO− (see Scheme 1) and one coordinated water molecule (Ow1), displaying a tricapped trigonal prismatic geometry [15] in compound 1. The bond distances about the Pr atom to the coordinating oxygen atoms show wide variation (Pr–O distances range from 2.443 to 2.606 Å), and O–Pr–O bond angles both fall in the normal range [16,17]. The HIDC2− ligands linking Pr atoms form a zigzag chain, and what is noteworthy is that the adjacent zigzag chains are parallel to construct a 2D zigzag layer by coordination of O4. Furthermore, the adjacent zigzag layers arranging back-to-back with each other are linked by dinuclear (Pr2O2) linkers to form a 3D framework depicted in Fig. 2. It is noteworthy that 1D waterchains with helical characters that adopt the alternate arrangement of Δ- and Λ-helical chains (Fig. 2) are observed in the solid state of 1. The hydrogen-bonding parameters are reported in Table S2. Since the existence of coordinated water molecules, the same chiral helical chains
Fig. 2. 3D network of 1 containing 1D race-helical chains and 2D zigzag layers running along the a axis.
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Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
(a)
(b)
Fig. 4. Photoluminescence property of compound 1 in benzene at room temperature excitation (λ = 362 nm).
(c)
Fig. 3. Schematic diagram showing the ins-(63)(65.8) topology.
are arranged in parallel into the layer with the same helical chirality. As can be seen from Fig. 2, the layers with the single helical chirality (Λ/Δ) are alternately embedded in the zigzag layers, leading to the formation of a three-dimensional framework with meso-characteristic. In order to predigest the structure, we view the Pr atom as a 4connected node (Fig. 3a) and the HIDC2− ligand as a 3-connected node (simplifying the HIDC2− as a blue pellet) as shown in Fig. 3b. Thus, the overall topology of 1 can be defined as a (3,4)-connected network with the Schäfli symbol of (63)(65.8) topology which is an ins net [18] as illustrated in Fig. 3c. The structure of the bulk materials for 1 was confirmed by matching its X-ray powder pattern with that generated from the corresponding single crystals at room temperature (Figure S2). By comparison, the acceptable match was observed between the simulated single-crystal Xray data patterns and the experimental powder X-ray diffraction patterns for bulk crystalline samples as obtained from the synthesis of the corresponding compound 1. Obviously, the fact clearly indicates that the final product is monophasic.
The photoluminescence property of complex 1 in benzene was investigated at room temperature. Three peaks are found in the emission spectrum, which were recorded by using the S0 → S1 excitation (λ = 362 nm). The intense peak centered at 609 nm is mainly from the 1 D2 → 3H4 transition, but it is also believed to be overlapped with a much weaker peak corresponding to the 3P0 → 3H5 transition [19]. The very weak emission peaks at 542 and 658 nm correspond to transitions from the 3P0 emissive state to the 3H5 and 3F2 levels, respectively (Fig. 4). To study the thermal stability of complex 1, thermalgravimetric analysis (TG) was performed under a nitrogen atmosphere. The first step of weight loss (observed 9.50%, calculated 9.72%) below 200 °C was assigned to the liberation of solved and coordinated water molecules (Fig. 5), and just then the framework was followed by a plateau of stability to 390 °C. When the temperature increased, the organic ligands started to decompose and the framework collapses (Fig. 5). In summary, a new 3D lanthanide coordination complex was successfully constructed by imidazole-4,5-dicarboxlylate and acetate mixed ligands for the first time. This structure contains Pr–HIDC2− zigzag layers, binuclear PrIII linkers and 1D race-helical chains. Furthermore, compound 1 displays the high thermal stability and the strong photoluminescent property.
Fig. 5. TGA curve of compound 1.
Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
Acknowledgements We are grateful to the National Natural Science Foundation of China (Nos. 20772037 and 21071056), the Science and Technology Planning Project of Guangdong Province (Grant Nos. 2006A10902002 and 2010B031100018), and the Natural Science Foundation of Guangdong Province (9251063101000006 and 06025033). Appendix A. Supplementary material X-ray crystallographic file in CIF format for compound 1 is available in the supporting material section. The CCDC reference number is CCDC 777811. Copy of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax: int code +44(1223) 336-033; E-mail: [email protected]]. Supplementary data to this article can be found online at doi:10.1016/j.inoche.2010.09.033. References [1] (a) M.D. Allendorf, C.A. Bauer, R.K. Bhakta, R.J.T. Houk, Chem. Soc. Rev. 38 (2009); (b) U. Mueller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt, J. Pastre, J. Mater. Chem. 16 (2006) 626; (c) A.R. Millward, O.M. Yaghi, J. Am. Chem. Soc. 127 (2005) 17998; (d) G. Férey, Chem. Soc. Rev. 37 (2008) 191. [2] (a) A. Henning, H.A. Hoppe, Angew. Chem. Int. Ed. 48 (2009) 2–13; (b) B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249 (2005) 545; (c) R.-Q. Zou, H. Sakurai, Q. Xu, Angew. Chem. Int. Ed. 45 (2006) 2542. [3] (a) F. Nouar, J.F. Eubank, T. Bousquet, L. Wojtas, M.J. Zaworotko, M. Eddaoudi, J. Am. Chem. Soc. 130 (2008) 1833; (b) H. Zhao, Z.-R. Qu, H.-Y. Ye, R.-G. Xiong, Chem. Soc. Rev. 37 (2008) 84; (c) D.N. Dybtsev, H. Chun, K. Kim, Angew. Chem. Int. Ed. 43 (2004) 5033. [4] (a) M. Dincă, J. Long, J. Am. Chem. Soc. 127 (2005) 9376; (b) T.K. Maji, K. Uemura, H.C. Chang, R. Matsuda, S. Kitagawa, Angew. Chem. Int. Ed. 43 (2004) 3269; (c) W.-C. Song, J.-R. Li, P.-C. Song, Y. Tao, Q. Yu, X.-L. Tong, X.-H. Bu, Inorg. Chem. 48 (2009) 1330. [5] (a) U. Mueller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt, J. Pastré, J. Mater. Chem. 6 (2006) 626; (b) L.S. Natrajan, A.J.L. Villaraza, A.M. Kenwright, S. Faulkner, Chem. Commun. (2009) 6020; (c) K. Binnemans, Chem. Rev. 109 (2009) 4283; (d) S. Swavey, R. Swavey, Coord. Chem. Rev. 253 (2009) 2627. [6] (a) J.R. Li, R.J. Kuppler, H.C. Zhou, Chem. Soc. Rev. 38 (2009) 1477; (b) J.R. Long, O.M. Yaghi, Chem. Soc. Rev. 38 (2009) 1213; (c) H. Wu, W. Zhou, T. Yildrim, J. Am. Chem. Soc. 129 (2007) 5314. [7] (a) V.A. Friese, D.G. Kurth, Coord. Chem. Rev. 252 (2008) 199; (b) J.-P. Zhang, X.-M. Chen, J. Am. Chem. Soc. 130 (2008) 6010; (b) Y.-L. Liu, V.C. Kravtsov, M. Eddaoudi, Angew. Chem. Int. Ed. 47 (2008) 8446. [8] (a) J.-Q. Chen, Y.-P. Cai, H.-C. Fang, Z.-Y. Zhou, X.-L. Zhan, G. Zhao, Z. Zhang, Cryst. Growth Des. 9 (2009) 1605; (c) Y.-P. Cai, H.-X. Zhang, A.-W. Xu, C.-Y. Su, C.-L. Chen, H.-Q. Liu, L. Zhang, B.-S. Kang, J. Chem. Soc. Dalton Trans. (2001) 2429. [9] (a) Y.-P. Cai, C.-Y. Su, A.-W. Xu, B.-S. Kang, Y.-X. Tong, H.-Q. Liu, J. Sun, Polyhedron 20 (2001) 657; (b) H.-C. Fang, X.-Y. Yi, Z.-G. Gu, G. Zhao, Q.-Y. Wen, J.-Q. Zhu, A.-W. Xu, Y.-P. Cai, Cryst. Growth Des. 9 (2010) 3776; (c) X.-X. Zhou, Y.-P. Cai, S.-Z. Zhu, Q.-G. Zhan, M.-S. Liu, Z.-Y. Zhou, L. Chen, Cryst. Growth Des. 8 (2008) 2076.
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[10] (a) Y.-P. Cai, X.-X. Zhou, Z.-Y. Zhou, S.-Z. Zhu, P.K. Thallapally, J. Liu, Inorg. Chem. 48 (2009) 6343; (b) Y.-P. Cai, Q.-Y. Yu, Z.-Y. Zhou, Z.-J. Hu, H.-C. Fang, N. Wang, Q.-G. Zhan, L. Chen, C.-Y. Su, CrystEngComm 11 (2009) 1006; (c) X.-M. Lin, H.-C. Fang, Z.-Y. Zhou, L. Chen, J.-W. Zhao, S.-Z. Zhu, Y.-P. Cai, CrystEngComm 11 (2009) 847. [11] (a) M.-S. Liu, Q.-Y. Yu, Y.-P. Cai, C.-Y. Su, X.-M. Lin, X.-X. Zhou, J.-W. Cai, Cryst. Growth Des. 8 (2008) 4083; (b) X.-M. Lin, Y. Ying, L. Chen, H.-C. Fang, Z.-Y. Zhou, Q.-G. Zhan, Y.-P. Cai, Inorg. Chem. Commun. 12 (2009) 316; (c) Z.-G. Gu, Y.-P. Cai, H.-C. Fang, Z.-Y. Zhou, P.K. Thallapally, J. Tian, J. Liu, G.J. Exarhos, Chem. Commun. 46 (2010) 5373. [12] Synthesis of [Pr(H2O)(C5HN2O4)(CH3COO)·H2O]n (1). A mixture of 4,5-imidazoledicarboxylic acid (0.156 g; 1 mmol), acetic acid (0.5 mL), Pr6O11 (0.171 g; 0.17 mmol), and H2O (12 mL) was heated to 160 °C for 80 h in a 20 mL Teflonlined stainless-steel autoclave and was then cooled to room temperature at 10 °C h− 1 to obtain green block single crystals of 1 (yield: 61% based on Pr) Anal. Calcd for PrC7H9N2O8 (%): C, 21.55; H, 2.33; N, 7.18. Found: C, 21.57; H, 2.34; N, 7.21. IR frequencies (K Br, cm−1): 3663, 3175, 1542, 1389, 1243, 1094, 964, 890, 849, 792, 664, 618, 537. [13] (a) S. Skanthakumar, Mark R. Antonio, Richard E. Wilson, L. Soderholm, Inorg. Chem. 46 (2009) 3485; (b) M.L. Ho, K.Y. Chen, G.H. Lee, Y.C. Chen, C.C. Wang, J.F. Lee, W.C. Chung, P.T. Chou, Inorg. Chem. 48 (2009) 10304. [14] Single crystal X-ray diffraction data collections for 1 was performed on a Bruker Apex II CCD diffractometer operating at 50 kV and 30 mA using Mo Ka radiation (λ = 0.71073 Å) at 296 K. Data collection and reduction were performed using the SMART and SAINT software. A multi-scan absorption correction was applied using the SADABS program [20]. The two structures were solved by direct methods and refined by full-matrix least squares on F2 using the SHELXTL program package [21]. Hydrogen atoms were located from difference Fourier maps and a riding model. Selected bond lengths and angles are given in Table S1. Crystallographic data for complex 1: PrC7H9N2O8, FW = 421.42, monoclinic, space group P21/c with a = 13.1277(6) Å, b = 6.591(3) Å, c = 12.8486(6) Å. V = 1104.75(9) Å3, Z = 4, F(000) = 792, GOF = 1.027, R1 = 0.0171, wR2 = 0.0388 [I N 2σ(I)]. [15] (a) T.K. Prasad, M.V. Rajasekharan, Cryst. Growth Des. 8 (2008) 1346; (b) N. Torapava, I. Persson, L. Eriksson, D. Lundberg, Inorg. Chem. 48 (2009) 11712. [16] (a) M.D. Regulacio, M.H. Pablico, J.A. Vasquez, P.N. Myers, S. Gentry, M. Prushan, S.T. Chang, S.L. Stoll, Inorg. Chem. 47 (2008) 1512; (b) B. Zhao, L. Yi, Y. Dai, X.-Y. Chen, P. Cheng, D.-Z. Liao, S.-P. Yan, Z.-H. Jiang, Inorg. Chem. 44 (2005) 911. [17] (a) X. Feng, J.-S. Zhao, B. Liu, L.-Y. Wang, S.W. Ng, G. Zhang, J.-G. Wang, X.-G. Shi, Y.-Y. Liu, Cryst. Growth Des. 10 (2010) 1399; (b) D. Lundberg, I. Persson, L. Eriksson, P. D'Angelo, S.D. Panfilis, Inorg. Chem. 49 (2010) 4420; (c) X. Li, B.-L. Wu, R.-Y. Wang, H.-Y. Zhang, C.-Y. Niu, Y.-Y. Niu, H.-W. Hou, Inorg. Chem. 49 (2010) 2601; (d) A.M. Corrente, T. Chivers, Inorg. Chem. 49 (2010) 2457. [18] (a) Q.-R. Fang, G.-S. Zhu, M. Xue, Z.-P. Wang, J.-Y. Sun, S.-L. Qiu Cryst, Growth Des. 8 (2008) 319; (b) S.-S. Chen, J. Fan, T.A. Okamura, M.-S. Chen, Z. Su, W.-Y. Sun, N. Ueyama, Cryst. Growth Des. 10 (2010) 812. [19] M.D. Regulacio, M.H. Pablico, J.A. Vasquez, P.N. Myers, S. Gentry, M. Prushan, S.W. T. Chang, S.L. Stoll, Inorg. Chem. 47 (2008) 1512. [20] G.M. Sheldrick, SADABS Program for Scaling and Correction of Area Detector Data, University of Göttingen, Göttingen, Germany, 1996. [21] Bruker, APEXII Software, Version 6.3.1, Bruker AXS Inc, Madison, Wisconsin, USA, 2004; G.M. Sheldrick, SHELXL-97, Program for X-ray Crystal Structure Refinement, University of Göttingen, Göttingen, Germany, 1997.
Contents lists available at ScienceDirect
Inorganic Chemistry Communications j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i n o c h e
A new 3D fluorescent lanthanide-organic framework containing helical chains and zigzag layers from mixed carboxylate ligands Zhi-Gang Gu, Jin-Hao Chen, Yue-Nan Chen, Yin Ying, Hui-Ming Peng, Hong-Yang Jia, Ming-Fang Wang, Shan-Shan Li, Yue-Peng Cai ⁎ School of Chemistry and Environment, Key Lab of Technology on Electrochemical Energy Storage and Power Generation in Guangdong Universities, Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006, PR China
a r t i c l e
i n f o
Article history: Received 30 August 2010 Accepted 27 September 2010 Available online 15 October 2010 Keywords: Lanthanide-organic framework Mixed carboxylate ligands Zigzag layer Race-helical chain Fluorescence
a b s t r a c t A new 3D lanthanide compound [Pr(H2O)(C5HN2O4)(CH3COO)·H2O]n (1) has been hydrothermally synthesized by employing 4,5-imidazoledicarboxylic (H3IDC) and acetic acid mixed ligands and characterized by element analysis, IR spectroscopy and thermal analysis, as well as single-crystal X-ray diffraction. The results show that complex 1 has a 3D (3,4)-connected network structure containing zigzag layers and 1D racehelical chains (P- and M-chains), which denote the first example of lanthanide coordination framework including the mixed ligands of imidazole-4,5-dicarboxlylate and acetate. Moreover, compound 1 displays a strong photoluminescent property and a high thermal stability. © 2010 Elsevier B.V. All rights reserved.
Over the last decade, self-assembly of metal-organic frameworks (MOFs) has been well developed, which has grown into a subject that attracts great attention because of their intriguing aesthetic and topological structures as well as their potential applications in fields such as optics, catalysis, magnetic devices, gas storage, separation and so on [1–4]. MOFs are generally constructed by discrete metal polyhedra or isolated small clusters coordinated to linking organic functional groups which have been widely used in the construction of metal–organic complexes with various dimensional networks and interesting properties [5–7]. During the course of our study, we have reported a series of low dimensional [8–10] and high dimensional [11,12] metal-organic frameworks. As a continuation of the previous work, our goal is to design and synthesize 3D metal-organic frameworks with the interesting topologies containing imidazole-4,5-dicarboxlylatic acid (H3IDC) and other auxiliary carboxylate. Here we report one 3D lanthanide metal-organic framework containing H3IDC and acetic acid, namely [Pr(H2O)(C5H2N2O4) (CH3COO)·H2O]n, which contains helical chains and zigzag layers. The unique structure not only leads to interesting topological arrangements, but also plays an important role in photoluminescent activities. Topological analysis suggests that the complex displays an ins-(3,4)-connected net with race-helical chains and zigzag layers. This complex also demonstrates an intensive photoluminescence and high
⁎ Corresponding author. Tel.: +86 020 39310383; fax: +86 020 39310187. E-mail address: [email protected] (Y.-P. Cai). 1387-7003/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2010.09.033
thermal stability. In this paper, we report its synthesis, crystal structure, thermal gravimetric analysis (TGA) and photoluminescence in details. Imidazole-4,5-dicarboxlylic and acetic acids are chosen as multifunctional ligands, mainly based on the following considerations: (i) as
Fig. 1. The coordination environment of the PrIII ion in 1. Hydrogen atoms have been omitted for clarity. Symmetry codes: (i) 1 + x, y, z; (ii) 1 − x, 1 − y, 1 − z; (iii) −1 + x, y, z; and (iv) −1 + x, 1.5 − y, −0.5 + z.
Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
Scheme 1. Coordination modes of (a) HIDC2− and (b) Ac− in 1.
an aromatic rigid ligand, H3IDC is easy to chelate metal center to form a 2D zigzag layer. (ii) Acetate ligand as non-aromatic has versatile coordination modes and can meet the high coordination number of lanthanide metal ions. (iii) The weak interactions of the mixed ligands may construct interesting helical chains. Compound 1 was synthesized hydrothermally with a mixture of praseodymium oxide, H3IDC, acetic acid and 15 mL water sealed in a 20 mL Teflon-lined stainless-steel autoclave and heated at 160 °C for 90 h [12]. The water molecules in compound 1 are proved by the strong and broad band at 3663 cm− 1, which is ascribed to the stretching vibrations νO–H. The strong bands of the N–H stretching frequencies in 1 are covered by the broad absorption bands of hydrogen bonds, the bands at 3175 cm− 1 may correspond to νN–H. The absorption bands at 1542 and 1389 cm− 1 cm− 1 for 1 correspond to the asymmetric mode
69
νas(COO−) and the symmetric mode νs(COO−) of the carboxylate groups, respectively. The difference of 253 cm− 1 between νas(COO−) and νs(COO−) in 1 indicates that bridging carboxylates are in the exobidentate mode [13], as proved by the X-ray crystal structure analysis. The structure analysis [14] reveals that complex 1 crystallizes in the P21/c space group and exhibits a 3D organic framework constructed from mixed Pr–HIDC2− layers, binuclear Pr linkers and hydrogen-bonded race-helical chains, in which the asymmetric unit includes one Pr(III) ion, one HIDC2−, one CH3COO−, one coordinated water and one lattice water. As shown in Fig. 1, Pr1 ion is nine-coordinated by four oxygen atoms (O1, O4, O5, and O6i) and one nitrogen atom (N1) from three μ3-HIDC2−, three oxygen atoms (O2, O3 and O3i) from two μ2-CH3COO− (see Scheme 1) and one coordinated water molecule (Ow1), displaying a tricapped trigonal prismatic geometry [15] in compound 1. The bond distances about the Pr atom to the coordinating oxygen atoms show wide variation (Pr–O distances range from 2.443 to 2.606 Å), and O–Pr–O bond angles both fall in the normal range [16,17]. The HIDC2− ligands linking Pr atoms form a zigzag chain, and what is noteworthy is that the adjacent zigzag chains are parallel to construct a 2D zigzag layer by coordination of O4. Furthermore, the adjacent zigzag layers arranging back-to-back with each other are linked by dinuclear (Pr2O2) linkers to form a 3D framework depicted in Fig. 2. It is noteworthy that 1D waterchains with helical characters that adopt the alternate arrangement of Δ- and Λ-helical chains (Fig. 2) are observed in the solid state of 1. The hydrogen-bonding parameters are reported in Table S2. Since the existence of coordinated water molecules, the same chiral helical chains
Fig. 2. 3D network of 1 containing 1D race-helical chains and 2D zigzag layers running along the a axis.
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Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
(a)
(b)
Fig. 4. Photoluminescence property of compound 1 in benzene at room temperature excitation (λ = 362 nm).
(c)
Fig. 3. Schematic diagram showing the ins-(63)(65.8) topology.
are arranged in parallel into the layer with the same helical chirality. As can be seen from Fig. 2, the layers with the single helical chirality (Λ/Δ) are alternately embedded in the zigzag layers, leading to the formation of a three-dimensional framework with meso-characteristic. In order to predigest the structure, we view the Pr atom as a 4connected node (Fig. 3a) and the HIDC2− ligand as a 3-connected node (simplifying the HIDC2− as a blue pellet) as shown in Fig. 3b. Thus, the overall topology of 1 can be defined as a (3,4)-connected network with the Schäfli symbol of (63)(65.8) topology which is an ins net [18] as illustrated in Fig. 3c. The structure of the bulk materials for 1 was confirmed by matching its X-ray powder pattern with that generated from the corresponding single crystals at room temperature (Figure S2). By comparison, the acceptable match was observed between the simulated single-crystal Xray data patterns and the experimental powder X-ray diffraction patterns for bulk crystalline samples as obtained from the synthesis of the corresponding compound 1. Obviously, the fact clearly indicates that the final product is monophasic.
The photoluminescence property of complex 1 in benzene was investigated at room temperature. Three peaks are found in the emission spectrum, which were recorded by using the S0 → S1 excitation (λ = 362 nm). The intense peak centered at 609 nm is mainly from the 1 D2 → 3H4 transition, but it is also believed to be overlapped with a much weaker peak corresponding to the 3P0 → 3H5 transition [19]. The very weak emission peaks at 542 and 658 nm correspond to transitions from the 3P0 emissive state to the 3H5 and 3F2 levels, respectively (Fig. 4). To study the thermal stability of complex 1, thermalgravimetric analysis (TG) was performed under a nitrogen atmosphere. The first step of weight loss (observed 9.50%, calculated 9.72%) below 200 °C was assigned to the liberation of solved and coordinated water molecules (Fig. 5), and just then the framework was followed by a plateau of stability to 390 °C. When the temperature increased, the organic ligands started to decompose and the framework collapses (Fig. 5). In summary, a new 3D lanthanide coordination complex was successfully constructed by imidazole-4,5-dicarboxlylate and acetate mixed ligands for the first time. This structure contains Pr–HIDC2− zigzag layers, binuclear PrIII linkers and 1D race-helical chains. Furthermore, compound 1 displays the high thermal stability and the strong photoluminescent property.
Fig. 5. TGA curve of compound 1.
Z.-G. Gu et al. / Inorganic Chemistry Communications 14 (2011) 68–71
Acknowledgements We are grateful to the National Natural Science Foundation of China (Nos. 20772037 and 21071056), the Science and Technology Planning Project of Guangdong Province (Grant Nos. 2006A10902002 and 2010B031100018), and the Natural Science Foundation of Guangdong Province (9251063101000006 and 06025033). Appendix A. Supplementary material X-ray crystallographic file in CIF format for compound 1 is available in the supporting material section. The CCDC reference number is CCDC 777811. Copy of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax: int code +44(1223) 336-033; E-mail: [email protected]]. Supplementary data to this article can be found online at doi:10.1016/j.inoche.2010.09.033. References [1] (a) M.D. Allendorf, C.A. Bauer, R.K. Bhakta, R.J.T. Houk, Chem. Soc. Rev. 38 (2009); (b) U. Mueller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt, J. Pastre, J. Mater. Chem. 16 (2006) 626; (c) A.R. Millward, O.M. Yaghi, J. Am. Chem. Soc. 127 (2005) 17998; (d) G. Férey, Chem. Soc. Rev. 37 (2008) 191. [2] (a) A. Henning, H.A. Hoppe, Angew. Chem. Int. Ed. 48 (2009) 2–13; (b) B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249 (2005) 545; (c) R.-Q. Zou, H. Sakurai, Q. Xu, Angew. Chem. Int. Ed. 45 (2006) 2542. [3] (a) F. Nouar, J.F. Eubank, T. Bousquet, L. Wojtas, M.J. Zaworotko, M. Eddaoudi, J. Am. Chem. Soc. 130 (2008) 1833; (b) H. Zhao, Z.-R. Qu, H.-Y. Ye, R.-G. Xiong, Chem. Soc. Rev. 37 (2008) 84; (c) D.N. Dybtsev, H. Chun, K. Kim, Angew. Chem. Int. Ed. 43 (2004) 5033. [4] (a) M. Dincă, J. Long, J. Am. Chem. Soc. 127 (2005) 9376; (b) T.K. Maji, K. Uemura, H.C. Chang, R. Matsuda, S. Kitagawa, Angew. Chem. Int. Ed. 43 (2004) 3269; (c) W.-C. Song, J.-R. Li, P.-C. Song, Y. Tao, Q. Yu, X.-L. Tong, X.-H. Bu, Inorg. Chem. 48 (2009) 1330. [5] (a) U. Mueller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt, J. Pastré, J. Mater. Chem. 6 (2006) 626; (b) L.S. Natrajan, A.J.L. Villaraza, A.M. Kenwright, S. Faulkner, Chem. Commun. (2009) 6020; (c) K. Binnemans, Chem. Rev. 109 (2009) 4283; (d) S. Swavey, R. Swavey, Coord. Chem. Rev. 253 (2009) 2627. [6] (a) J.R. Li, R.J. Kuppler, H.C. Zhou, Chem. Soc. Rev. 38 (2009) 1477; (b) J.R. Long, O.M. Yaghi, Chem. Soc. Rev. 38 (2009) 1213; (c) H. Wu, W. Zhou, T. Yildrim, J. Am. Chem. Soc. 129 (2007) 5314. [7] (a) V.A. Friese, D.G. Kurth, Coord. Chem. Rev. 252 (2008) 199; (b) J.-P. Zhang, X.-M. Chen, J. Am. Chem. Soc. 130 (2008) 6010; (b) Y.-L. Liu, V.C. Kravtsov, M. Eddaoudi, Angew. Chem. Int. Ed. 47 (2008) 8446. [8] (a) J.-Q. Chen, Y.-P. Cai, H.-C. Fang, Z.-Y. Zhou, X.-L. Zhan, G. Zhao, Z. Zhang, Cryst. Growth Des. 9 (2009) 1605; (c) Y.-P. Cai, H.-X. Zhang, A.-W. Xu, C.-Y. Su, C.-L. Chen, H.-Q. Liu, L. Zhang, B.-S. Kang, J. Chem. Soc. Dalton Trans. (2001) 2429. [9] (a) Y.-P. Cai, C.-Y. Su, A.-W. Xu, B.-S. Kang, Y.-X. Tong, H.-Q. Liu, J. Sun, Polyhedron 20 (2001) 657; (b) H.-C. Fang, X.-Y. Yi, Z.-G. Gu, G. Zhao, Q.-Y. Wen, J.-Q. Zhu, A.-W. Xu, Y.-P. Cai, Cryst. Growth Des. 9 (2010) 3776; (c) X.-X. Zhou, Y.-P. Cai, S.-Z. Zhu, Q.-G. Zhan, M.-S. Liu, Z.-Y. Zhou, L. Chen, Cryst. Growth Des. 8 (2008) 2076.
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[10] (a) Y.-P. Cai, X.-X. Zhou, Z.-Y. Zhou, S.-Z. Zhu, P.K. Thallapally, J. Liu, Inorg. Chem. 48 (2009) 6343; (b) Y.-P. Cai, Q.-Y. Yu, Z.-Y. Zhou, Z.-J. Hu, H.-C. Fang, N. Wang, Q.-G. Zhan, L. Chen, C.-Y. Su, CrystEngComm 11 (2009) 1006; (c) X.-M. Lin, H.-C. Fang, Z.-Y. Zhou, L. Chen, J.-W. Zhao, S.-Z. Zhu, Y.-P. Cai, CrystEngComm 11 (2009) 847. [11] (a) M.-S. Liu, Q.-Y. Yu, Y.-P. Cai, C.-Y. Su, X.-M. Lin, X.-X. Zhou, J.-W. Cai, Cryst. Growth Des. 8 (2008) 4083; (b) X.-M. Lin, Y. Ying, L. Chen, H.-C. Fang, Z.-Y. Zhou, Q.-G. Zhan, Y.-P. Cai, Inorg. Chem. Commun. 12 (2009) 316; (c) Z.-G. Gu, Y.-P. Cai, H.-C. Fang, Z.-Y. Zhou, P.K. Thallapally, J. Tian, J. Liu, G.J. Exarhos, Chem. Commun. 46 (2010) 5373. [12] Synthesis of [Pr(H2O)(C5HN2O4)(CH3COO)·H2O]n (1). A mixture of 4,5-imidazoledicarboxylic acid (0.156 g; 1 mmol), acetic acid (0.5 mL), Pr6O11 (0.171 g; 0.17 mmol), and H2O (12 mL) was heated to 160 °C for 80 h in a 20 mL Teflonlined stainless-steel autoclave and was then cooled to room temperature at 10 °C h− 1 to obtain green block single crystals of 1 (yield: 61% based on Pr) Anal. Calcd for PrC7H9N2O8 (%): C, 21.55; H, 2.33; N, 7.18. Found: C, 21.57; H, 2.34; N, 7.21. IR frequencies (K Br, cm−1): 3663, 3175, 1542, 1389, 1243, 1094, 964, 890, 849, 792, 664, 618, 537. [13] (a) S. Skanthakumar, Mark R. Antonio, Richard E. Wilson, L. Soderholm, Inorg. Chem. 46 (2009) 3485; (b) M.L. Ho, K.Y. Chen, G.H. Lee, Y.C. Chen, C.C. Wang, J.F. Lee, W.C. Chung, P.T. Chou, Inorg. Chem. 48 (2009) 10304. [14] Single crystal X-ray diffraction data collections for 1 was performed on a Bruker Apex II CCD diffractometer operating at 50 kV and 30 mA using Mo Ka radiation (λ = 0.71073 Å) at 296 K. Data collection and reduction were performed using the SMART and SAINT software. A multi-scan absorption correction was applied using the SADABS program [20]. The two structures were solved by direct methods and refined by full-matrix least squares on F2 using the SHELXTL program package [21]. Hydrogen atoms were located from difference Fourier maps and a riding model. Selected bond lengths and angles are given in Table S1. Crystallographic data for complex 1: PrC7H9N2O8, FW = 421.42, monoclinic, space group P21/c with a = 13.1277(6) Å, b = 6.591(3) Å, c = 12.8486(6) Å. V = 1104.75(9) Å3, Z = 4, F(000) = 792, GOF = 1.027, R1 = 0.0171, wR2 = 0.0388 [I N 2σ(I)]. [15] (a) T.K. Prasad, M.V. Rajasekharan, Cryst. Growth Des. 8 (2008) 1346; (b) N. Torapava, I. Persson, L. Eriksson, D. Lundberg, Inorg. Chem. 48 (2009) 11712. [16] (a) M.D. Regulacio, M.H. Pablico, J.A. Vasquez, P.N. Myers, S. Gentry, M. Prushan, S.T. Chang, S.L. Stoll, Inorg. Chem. 47 (2008) 1512; (b) B. Zhao, L. Yi, Y. Dai, X.-Y. Chen, P. Cheng, D.-Z. Liao, S.-P. Yan, Z.-H. Jiang, Inorg. Chem. 44 (2005) 911. [17] (a) X. Feng, J.-S. Zhao, B. Liu, L.-Y. Wang, S.W. Ng, G. Zhang, J.-G. Wang, X.-G. Shi, Y.-Y. Liu, Cryst. Growth Des. 10 (2010) 1399; (b) D. Lundberg, I. Persson, L. Eriksson, P. D'Angelo, S.D. Panfilis, Inorg. Chem. 49 (2010) 4420; (c) X. Li, B.-L. Wu, R.-Y. Wang, H.-Y. Zhang, C.-Y. Niu, Y.-Y. Niu, H.-W. Hou, Inorg. Chem. 49 (2010) 2601; (d) A.M. Corrente, T. Chivers, Inorg. Chem. 49 (2010) 2457. [18] (a) Q.-R. Fang, G.-S. Zhu, M. Xue, Z.-P. Wang, J.-Y. Sun, S.-L. Qiu Cryst, Growth Des. 8 (2008) 319; (b) S.-S. Chen, J. Fan, T.A. Okamura, M.-S. Chen, Z. Su, W.-Y. Sun, N. Ueyama, Cryst. Growth Des. 10 (2010) 812. [19] M.D. Regulacio, M.H. Pablico, J.A. Vasquez, P.N. Myers, S. Gentry, M. Prushan, S.W. T. Chang, S.L. Stoll, Inorg. Chem. 47 (2008) 1512. [20] G.M. Sheldrick, SADABS Program for Scaling and Correction of Area Detector Data, University of Göttingen, Göttingen, Germany, 1996. [21] Bruker, APEXII Software, Version 6.3.1, Bruker AXS Inc, Madison, Wisconsin, USA, 2004; G.M. Sheldrick, SHELXL-97, Program for X-ray Crystal Structure Refinement, University of Göttingen, Göttingen, Germany, 1997.