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Three cucurbit[5]uril-based heterometallic complexes
Journal of Molecular Structure 1006 (2011) 87–90
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc
Three cucurbit[5]uril-based heterometallic complexes Li-Li Liang, Kai Chen, Xing Feng, Yun-Qian Zhang, Qian-Jiang Zhu, Sai-Feng Xue, Zhu Tao ⇑ Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, People’s Republic of China
a r t i c l e
i n f o
Article history: Received 10 April 2011 Accepted 29 July 2011 Available online 22 August 2011 Keywords: Cucurbit[5]uril Heterometallic Capsules
a b s t r a c t In the present study, we report three crystal structures of heterometallic Q[5]-based complexes. They are complexes of heterometallic cadmium and potassium ions/Q[5] capsules with a stoichiometry of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1), heterometallic praseodymium and calcium/Q[5] pairs with a stoichiometry of 2{[Ca(H2O)(OH)]-l-[Pr(H2O)3[Cl@Q[5]]]}3+6Cl32H2O (2) and discrete heterometallic neodymium and potassium ions/Q[5] capsules with a stoichiometry of {[Nd(H2O)3] [(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3). Ó 2011 Published by Elsevier B.V.
1. Introduction Cucurbit[n]urils (Q[n]s) [1] as shown in Fig. 1 have proved to be a promising class of ligands and organic building blocks because these macrocycles have two open portals with a unique cavity rimmed with carbonyl groups, and they readily coordinate with various metal ions to form various supramolecular coordination polymers, networks and frameworks, which are aesthetics as well as the potential for nanoscale applications toward molecular devices and new materials. Therefore, the Q[n]-based coordination chemistry has been receiving considerable attention [2,3]. Amongst these metal– Q[n] complexes are few heterometallic Q[n]-based complexes, in which a kind of metal ion coordinates to one portal of a Q[n], and the second kind of metal ions coordinates to the other portal of the Q[n] [4–7]. Although Fedin et al. demonstrated a series of second metal-containing cluster interacting with Q[6] through hydrogen bonding [8–12], the first several examples of such complexes was reported by Thuery, when uranyl nitrate is reacted with Q[5] in the presence of alkali metal salts, mixed capsules, capped by one uranyl ion at one portal and K+ or Cs+ at the other, are obtained as dicationic species [4]. Recently, when we focus on study of the Q[n]-based networks and frameworks constructed through direct coordination of metal ions to the Q[n]s [13,14], we found that the introduction of the third species, into Q[5]–metal systems could result in the formation of Q[n]-based networks and frameworks, the species can be organic molecules, or inorganic metal salts. For example, normally, potassium metal ions can coordinate to Q[5] molecules and form one dimensional coordination polymers [15], when ZnCl2 salt is ⇑ Corresponding author. Address: Institute of Applied Chemistry, Guizhou University, Guiyang 550025, People’s Republic of China. Tel.: +86 851 3623903; fax: +86 851 3620906. E-mail address: [email protected] (Z. Tao). 0022-2860/$ - see front matter Ó 2011 Published by Elsevier B.V. doi:10.1016/j.molstruc.2011.07.062
introduced into the Q[5]–K+ system, an infinite 1D supramolecular chain is constructed of heterometallic zinc and potassium ions/ cucurbit[5]uril capsules through ion–dipole interaction and hydrogen binding, and the stacking of the chains forms a novel hexagonal open framework [6]. In the present study, we report three crystal structures of heterometallic Q[5]-based complexes. They are complexes of heterometallic cadmium and potassium ions/Q[5] capsules with a stoichiometry of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1), heterometallic praseodymium and calcium/Q[5] pairs with a stoichiometry of 2{[Ca(H2O)(OH)]-l-[Pr (H2O)3 [Cl@Q [5]]]}3+ 6Cl32H2O (2) and discrete heterometallic neodymium and potassium ions/Q[5] capsules with a stoichiometry of {[Nd(H2O)3] [(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3). 2. Experimental 2.1. General materials Chemicals, such as CaCl2, CdCl2, KCl, Pr(NO3)3 and Nd(NO3)3 were of reagent grade and used without further purification. The ligand compound Q[5] was prepared by the reported procedures previously [16,17]. Elemental analysis was carried out a EURO EA-3000 element analyzer. 2.2. Preparation of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1) The single crystal of the compound 1 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), KCl (15 mg, 0.20 mmol) and CdCl2 (55 mg, 0.30 mmol) in 10 mL of water was refluxed for 5 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding
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L.-L. Liang et al. / Journal of Molecular Structure 1006 (2011) 87–90 Table 1 Crystallographic data for complexes 1–3.
Fig. 1. Structures of the cucurbit[n]urils.
colorless crystals within 5 days (39% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C30H50N20O20Cd2KCl5 (%): C, 24.82, H, 3.47, N, 19.29; found: C, 25.17, H, 3.38, N, 19.40. 2.3. Preparation of 2{[Ca(H2O)(OH)]-l-[Pr(H2O)3[Cl@Q[5]]]}3+ 6Cl32H2O (2) The single crystal of the complex 2 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), CaCl2 (22 mg, 0.20 mmol) and PrCl3 (74 mg, 0.30 mmol) in 10 mL of water was refluxed for 30 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding colorless crystals within 7 days (51% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C60H146N40O64Pr2Ca2Cl8 (%): C 23.26, H 4.75, N 18.09; found: C 23.57, H 4.61, N 18.23. 2.4. Preparation of {[Nd(H2O)3][(NO3)@Q[5]][K(H2O)][Nd(H2O)3 (NO3)4]}2+2(NO3)8H2O (3) The single crystal of the compound 3 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), KCl (15 mg, 0.20 mmol) and Nd(NO3)3 (99 mg, 0.30 mmol) in 10 mL of water was refluxed for 30 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding magenta crystals within 8 days (56% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C30H60N27O46Nd2K (%): C 19.35, H 3.25, N 20.30; found: C 19.27, H 3.18, N 20.40. 2.5. Crystallography The data of the four supramolecular assemblies were collected on a Bruker Apex-2000 CCD diffractometer using graphite monochromated Mo Ka radiation (k = 0.71073 Å) in x scan mode. Lorentz polarization and absorption corrections were applied. Structural solution and full matrix least-squares refinement based on F2 were performed with the SHELXS-97 and SHELXL-97 program package [18,19], respectively. All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were generated geometrically. Details of the crystal parameters, data collection, and refinements for complexes 1–3 are summarized in Table 1. Further details are provided in the Supporting information. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as deposition Nos.: CCDC 820002 (1), CCDC 820003 (2), CCDC 820004 (3). Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223/336 033; [email protected]). 3. Results and discussion 3.1. Crystal structure of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3 (H2O)2]7H2O (1) The X-ray structure of 1 reveals a one dimensional supramolecular chain constructed of heterometallic cadmium and potassium ions/cucurbit[5]uril capsules through the hydrogen bonding. The
a b
Compound
1
2
3
Empirical formula Formula weight Crystal system Space group a (Å) b (Å) c (Å) a (°) b (°) c (°) V (Å3) Z k (Å) Dcalcd. (g cm3) T (K) Unique reflns Obsd reflns Params Rint R [I > 2r(I)]a wR[I > 2r(I)]b
C30H50N20O20Cd2KCl5 C60H146N40O64Pr2Ca2Cl8 C30H60N27O46Nd2K 1452.02
3097.75
1862.63
Orthorhombic
Monoclinic
Triclinic
P212121 12.0196(16) 16.529(2) 24.768(3) 90.00 90.00 90.00 4920.7(11) 4 0.71073 1.960
C 2/m 24.146(2) 15.1185(13) 34.302(3) 90.00 108.377(2) 90.00 11883.6(18) 4 0.71073 1.731
P-1 12.0577(8) 13.8132(10) 18.3926(13) 88.412(2) 82.692(2) 88.700(2) 3036.8(4) 2 0.71703 2.037
223 8643 8252 703 0.0309 0.0313 0.0831
223 11804 10495 899 0.0281 0.0547 0.1506
223 11541 10486 956 0.0406 0.0516 0.1432
Conventional R on Fhkl: R||Fo| |Fc||/R|Fo|. Weighted R on |Fhkl|2: R½wðF 2o F 2c Þ2 =R½wðF 2o Þ2 1=2 .
capsule is fully capped by cadmium and potassium cations at its two portals (referring to Fig. 2a). Both of cation Cd1 and K1 coordinated to seven atoms: for the Cd cation, five carbonyl oxygens (O1, O2, O3, O4, and O5); a chloride anion (Cl1) at a portal of Q[5]; an included chloride anion (Cl2) shared with potassium cation at other portal of the Q[5]. For the K1 cation, five carbonyl oxygens (O6, O7, O8, O9, and O10); a water molecule (O10W) at the other portal of Q[5]; an included chloride anion (Cl2) shared with cadmium cation at the portal of the Q[5]. The distances between the capped ion Cd1 and carbonyl oxygens of Q[5] are 2.567(4) Å (Cd1–O1), 2.491(4) Å (Cd1–O2), 2.683(5) Å (Cd1–O3), 2.534(5) Å (Cd1–O4), 2.512(5) Å (Cd1–O5), the average distance is 2.557 Å. The distances between the capped ion Cd1 and the coordinated Cl1 anion at the portal is 2.445 Å. The distances between the capped ion K1 and carbonyl oxygens of Q[5] are 2.765(4) Å (K1–O6), 2.654(4) Å (K1–O7), 2.661(5) Å (K1–O8), 2.762(5) Å (K1–O9), 2.660(5) Å (K1–O10), the average distance is 2.701 Å. The distances between the capped ion K1 and the coordinated water molecule (O3W) is 2.751 Å. The distances between the capped ion Cd1 or K1 and the included Cl2 anion is 2.469 and 3.550 Å respectively. The neighboring capsules are linked by the coordinated water molecules (O3W) and two latticed water molecules O5W and O7W through hydrogen binding of O2–O7W–O7 (O2–O7W, 2.828 Å and O7W–O7, 2.762 Å); O3W–O3 (2.933 Å) and O8–O5W–O4 (O8–O5W, 2.825 Å and O5W–O4, 2.956 Å). Thus, a 1D supramolecular chain is formed (referring to Fig. 2b). Remarkably, the supramolecular chains arranged in a honeycomb structure with linear hexagonal channels extended along the a axis in 1 (referring to Fig. 2c) [20]. Each channel constructed of six paralleled supramolecular chains has an around 11.6 Å 8.8 Å section, and is filled with [Cd(H2O)2Cl3] complex anions (referring to Fig. 2d and e). The included [Cd(H2O)2Cl3] anions interact with the coordinated and latticed water molecules and discrete chloride anions through hydrogen bonding interaction, that leads to the formation of a complicated non-covalent interaction network. The channels or the void constructed of the wall of the cucurbit[5]uril appear to favor including or containing larger anions. In our recent work, we have demonstrated the ring with eight interlinked Q[5]
L.-L. Liang et al. / Journal of Molecular Structure 1006 (2011) 87–90
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Fig. 2. X-ray crystal structure of (a) the heterometallic metal ions/cucurbit[5]uril capsule; (b) the 1D supramolecular chain based on the capsules; (c) view of honeycomb structure with linear channels extended along the a axis; view of a hexagonal channel filled with [Cd(H2O)2Cl3], (d) top view, (e) side view.
‘‘beads’’ including four large anion InCl4 [13]. A more recent study 2 also showed that large anions ZnCl4 can be contained in the channels constructed of the walls of the Q[5]s, instead of including in the cavity of the Q[n]s [6]. 3.2. Crystal structure of 2{Ca(H2O)2(OH)-l-[Pr(H2O)3Cl@Q5]} 6Cl32(H2O) (2) The X-ray structure of 2 reveals a novel heterometallic cucurbit[5]uril pair, in which two Q[5] molecules are linked by a [Ca2(l-H2O)2(H2O)2] unit through direct coordination of calcium to portal carbonyl of the Q[5]s. while the other opening portal of the two Q[5] molecules in the unit is fully capped by praseodymium cations (referring to Fig. 3a). The Ca1 cation coordinates to nine oxygen atoms: four carbonyl oxygens belong to two Q[5] molecules in the unit (O4, O5, and O10, O11); two water molecules (O5W, O6W), which are shared with another Ca1 cation in the unit; two water molecules O7W and O8W (both of them with a 50% occupancy). The Pr1 or Pr2 cation also coordinates to nine atoms: five carbonyl oxygens (2O1, 2O2 and O3 or 2O7, 2O8 and O9); three coordinated water molecule (2O1W and O2W or O3W and 2O4W); an included chloride anion (Cl1 or Cl2) respectively. The distances between the capped ion Ca1 and carbonyl oxygens of two Q[5]s are 2.448 Å (Ca1–O4), 2.413 Å (Ca1–O5), 2.442 Å
(Ca1–O10), 2.432 Å (Ca1–O11), respectively, the average distance is 2.444 Å. The distances between the capped ion Ca1 and the coordinated water molecules are in the range of 2.406–2.497 Å. The distances between the capped ion Pr1 or Pr2 and carbonyl oxygens of Q[5] are 2.517 Å (Pr1–O1), 2.587 Å (Pr1–O2) and 2.535 Å (Pr1– O3), or 2.538 Å (Pr2–O7), 2.542 Å (Pr2–O8) and 2.519 Å (Pr2–O9), respectively, the average distance is 2.540 Å. The distances between the capped ion Pr1 or Pr2 and the coordinated water molecules are 2.573 Å (Pr1–O1W) and 2.566 Å (Pr1–O2W) or 2.568 Å (Pr2–O3W) and 2.535 Å (Pr2–O4W), respectively, the average distance is 2.561 Å. The distance between Pr1 or Pr2 and the included chloride anion Cl1 or Cl2 is 2.778 Å or 2.794 Å. It is common that larger cucurbit[n]urils, such as Q[6], Q[7] or Q[8], which have larger portals, could be capped with two or three metal ions at one portal [5,20,21]. To our knowledge, it is the first several Q[5]–metal complexes, in which a portal of a Q[5] molecule is capped with two metal ions [22]. In the present case, the Ca2+ and Pr3+ cations have similar ionic diameters, 0.99 Å and 1.01 Å respectively. When the Pr3+ cation fully coordinates on a portal of a Q[5] molecule, the other portal of the Q[5] molecule could be enlarged. The average distances of the center of five portal oxygen to these portal oxygens are 2.686 Å (Ca2+ capped) and 2.480 Å Pr3+ capped) respectively, there is 0.2 Å difference (referring to Fig. 3b). It suggests that the portal is too large to be fully capped
Fig. 3. X-ray crystal structure of (left) the heterometallic metal ions/cucurbit[5]uril pair linked by a [Ca2(l-H2O)2(H2O)2] unit; (b) the portal size data of a heterometallic Pr3+ and Ca2+ metal ions/cucurbit[5]uril complex.
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into a metal–Q[5] system, it could lead to the formation of a new novel Q[5]-based architecture. When a K–Q[5] system is introduced CdCl2 salt, the X-ray structure of 1 reveals a honeycomb structure constructed of one dimensional supramolecular chain of the heterometallic cadmium and potassium ions/cucurbit[5]uril capsules; when a Pr–Q[5] system is introduced CaCl2 salt, the first several Q[5]–metal complexes, in which a portal of a Q[5] molecule is capped with two metal ions, can be obtained. The strategy of introduction of a third species into a metal–Q[n] system could results in the formation of a novel Q[n]-based architecture, and we are at present embarking on studies of this type. Fig. 4. X-ray crystal structure of the heterometallic Nd3+ and K+ metal ions/ cucurbit[5]uril capsule and a linked [Nd(H2O)3(NO3)4] complex.
by one metal ion, which has a similar ionic diameter, such as the calcium ion. Thus, [Ca2(l-H2O)2(Cl)2] units capped on the portals of Q[5]s in the Q[5] pair can be observed in 2. 3.3. Crystal structure of {[Nd(H2O)3][(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3)
Acknowledgments We thank the National Natural Science Foundation of China (NSFC; No. 20961002 and 20971002), Natural Science Foundation of the Education Department of Guizhou Province, the Science and Technology Fund of Guizhou Province, and the International Collaborative Project Fund of Guizhou province for the financial support. Appendix A. Supplementary material
The X-ray structural analysis reveals discrete heterometallic neodymium and potassium/cucurbit[5]uril capsules in 3. In each capsule, the K1 cation coordinates to ten oxygen atoms: five carbonyl oxygens (O6, O7, O8, O9 and O10); one water molecule (O3W); two oxygens (O11 and O12) of a coordinated nitrate anion at the portal; two oxygens (O29 and O30) of an included nitrate anion in the cavity of the Q[5] molecule. The Nd1 cation coordinates to nine oxygen atoms: five carbonyl oxygens (O1, O2, O3, O4 and O5); three coordinated water molecule (O4W, O5W and O6W); one of three oxygens (O31) of the included nitrate anion in the cavity of the Q[5] molecule. Compared to the average distance (2.701 Å) of K1–O(carbonyl) in 1, the average distance between the capped ion K1 and carbonyl oxygens is 2.783 Å in 3, slightly longer than that in 1. The distances between the capped ion Nd1 and carbonyl oxygens of Q[5] are in the range of 2.511–2.570 Å, similar to those of Pr–O(carbonyl) in 2. The distances between the capped ion K1 and the coordinated water molecule (O6W) is 3.257 Å. The distances between the capped ion Nd1 and the coordinated water molecule are 2.472 Å (Nd1–O5W), 2.482 Å (Nd1– O7W) and 2.448 Å (Nd1–O8W), respectively. The distances between the included nitrate anion and the two capped cation ions are 3.181 Å (K1–O31) and 2.983 Å (K1–O30) and 2.374 Å (Nd– O29), respectively. In additional, a [Nd(H2O)3(NO3)4] anion complex linked to the molecular capsule through the coordination the K1 cation to one of nitrate anion in the anion complex (see Fig. 4). 4. Conclusion In the present study, three heterometallic metal ions/Q[5] systems are introduced. When the second inorganic salt is introduced
Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.molstruc.2011.07.062. References [1] Review: J. Lagona, P. Mukhopadhyay, S. Chakrabarti, L. Isaacs, Angew. Chem., Int. Ed. 44 (2005) 4844. [2] K.M. Park, S.Y. Kim, J. Heo, D. Whang, S. Sakamoto, K. Yamaguchi, K. Kim, J. Am. Chem. Soc. 124 (2002) 2140. [3] H. Cong, Q.J. Zhu, S.F. Xue, Z. Tao, G. Wei, Chin. Sci. Bull. 55 (2010) 3633. [4] P. Thuery, Cryst. Growth Des. 9 (2009) 1208. [5] P. Thuery, Inorg. Chem. 48 (2009) 825. [6] X. Xiao, K. Chen, S.F. Xue, Q.J. Zhu, Z. Tao, G. Wei, J. Mol. Struct. 969 (2010) 216. [7] J.X. Liu, Y.F. Gu, R.L. Lin, W.R. Yao, X.H. Liu, J. Zhu, Supramol. Chem. 22 (2010) 130. [8] R. Hernandez-Molina, M.N. Sokolov, A.G. Sykes, Acc. Chem. Res. 34 (2001) 223. [9] V.P. Fedin, Russ. Chem. Bull. 52 (2003) 1041. [10] R. Hernandez-Molina, M. Sokolov, P. Esparza, C. Vicent, R. Llusar, Dalton (2004) 847. [11] R. Hernandez-Molina, M.N. Sokolov, M. Clausen, W. Clegg, Inorg. Chem. 45 (2006) 10567. [12] O.A. Gerasko, E.A. Mainicheva, M.I. Naumova, M. Neumaier, M.M. Kappes, S. Lebedkin, D. Fenske, V.P. Fedin, Inorg. Chem. 47 (2008) 8869. [13] X.L. Ni, J.X. Lin, Y.Y. Zheng, W.S. Wu, Y.Q. Zhang, S.F. Xue, Q.J. Zhu, Z. Tao, A.I. Day, Cryst. Growth Des. 8 (2008) 3446. [14] Z.F. Li, F. Wu, F.G. Zhou, X.L. Ni, X. Feng, X. Xiao, Y.Q. Zhang, S.F. Xue, Q.J. Zhu, L.F. Lindoy, J.K. Clegg, Z. Tao, G. Wei, Cryst. Growth Des. 10 (2010) 5113. [15] J.X. Liu, L.S. Long, R.B. Huang, L.S. Zheng, Cryst. Growth Des. 6 (2006) 2611. [16] J. Kim, I.S. Jung, S.Y. Kim, E. Lee, J.K. Kang, S. Sakamoto, K. Yamaguchi, K. Kim, J. Am. Chem. Soc. 122 (2000) 540. [17] A.I. Day, A.P. Arnold, WO 0068232, 2000, p. 8. [18] G.M. Sheldrick, Acta Crystallogr. A 46 (1990) 467. p. 423. [19] G.M. Sheldrick, SHELXL-97 Program for the Solution and Refinement of Crystal Structures, University of Göttingen, Germany, 1997. [20] J.X. Liu, C.H. Dong, L.S. Long, R.B. Huang, L.S. Zheng, Dalton Trans. 36 (2009) 7344. [21] J. Heo, S.Y. Kim, D. Whang, K. Kim, Angew. Chem., Int. Ed. 38 (1999) 641. [22] Y.Q. Zhang, J.P. Zeng, Q.J. Zhu, S.F. Xue, Z. Tao, J. Mol. Struct. 929 (2009) 167.
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc
Three cucurbit[5]uril-based heterometallic complexes Li-Li Liang, Kai Chen, Xing Feng, Yun-Qian Zhang, Qian-Jiang Zhu, Sai-Feng Xue, Zhu Tao ⇑ Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, People’s Republic of China
a r t i c l e
i n f o
Article history: Received 10 April 2011 Accepted 29 July 2011 Available online 22 August 2011 Keywords: Cucurbit[5]uril Heterometallic Capsules
a b s t r a c t In the present study, we report three crystal structures of heterometallic Q[5]-based complexes. They are complexes of heterometallic cadmium and potassium ions/Q[5] capsules with a stoichiometry of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1), heterometallic praseodymium and calcium/Q[5] pairs with a stoichiometry of 2{[Ca(H2O)(OH)]-l-[Pr(H2O)3[Cl@Q[5]]]}3+6Cl32H2O (2) and discrete heterometallic neodymium and potassium ions/Q[5] capsules with a stoichiometry of {[Nd(H2O)3] [(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3). Ó 2011 Published by Elsevier B.V.
1. Introduction Cucurbit[n]urils (Q[n]s) [1] as shown in Fig. 1 have proved to be a promising class of ligands and organic building blocks because these macrocycles have two open portals with a unique cavity rimmed with carbonyl groups, and they readily coordinate with various metal ions to form various supramolecular coordination polymers, networks and frameworks, which are aesthetics as well as the potential for nanoscale applications toward molecular devices and new materials. Therefore, the Q[n]-based coordination chemistry has been receiving considerable attention [2,3]. Amongst these metal– Q[n] complexes are few heterometallic Q[n]-based complexes, in which a kind of metal ion coordinates to one portal of a Q[n], and the second kind of metal ions coordinates to the other portal of the Q[n] [4–7]. Although Fedin et al. demonstrated a series of second metal-containing cluster interacting with Q[6] through hydrogen bonding [8–12], the first several examples of such complexes was reported by Thuery, when uranyl nitrate is reacted with Q[5] in the presence of alkali metal salts, mixed capsules, capped by one uranyl ion at one portal and K+ or Cs+ at the other, are obtained as dicationic species [4]. Recently, when we focus on study of the Q[n]-based networks and frameworks constructed through direct coordination of metal ions to the Q[n]s [13,14], we found that the introduction of the third species, into Q[5]–metal systems could result in the formation of Q[n]-based networks and frameworks, the species can be organic molecules, or inorganic metal salts. For example, normally, potassium metal ions can coordinate to Q[5] molecules and form one dimensional coordination polymers [15], when ZnCl2 salt is ⇑ Corresponding author. Address: Institute of Applied Chemistry, Guizhou University, Guiyang 550025, People’s Republic of China. Tel.: +86 851 3623903; fax: +86 851 3620906. E-mail address: [email protected] (Z. Tao). 0022-2860/$ - see front matter Ó 2011 Published by Elsevier B.V. doi:10.1016/j.molstruc.2011.07.062
introduced into the Q[5]–K+ system, an infinite 1D supramolecular chain is constructed of heterometallic zinc and potassium ions/ cucurbit[5]uril capsules through ion–dipole interaction and hydrogen binding, and the stacking of the chains forms a novel hexagonal open framework [6]. In the present study, we report three crystal structures of heterometallic Q[5]-based complexes. They are complexes of heterometallic cadmium and potassium ions/Q[5] capsules with a stoichiometry of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1), heterometallic praseodymium and calcium/Q[5] pairs with a stoichiometry of 2{[Ca(H2O)(OH)]-l-[Pr (H2O)3 [Cl@Q [5]]]}3+ 6Cl32H2O (2) and discrete heterometallic neodymium and potassium ions/Q[5] capsules with a stoichiometry of {[Nd(H2O)3] [(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3). 2. Experimental 2.1. General materials Chemicals, such as CaCl2, CdCl2, KCl, Pr(NO3)3 and Nd(NO3)3 were of reagent grade and used without further purification. The ligand compound Q[5] was prepared by the reported procedures previously [16,17]. Elemental analysis was carried out a EURO EA-3000 element analyzer. 2.2. Preparation of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3(H2O)2]7H2O (1) The single crystal of the compound 1 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), KCl (15 mg, 0.20 mmol) and CdCl2 (55 mg, 0.30 mmol) in 10 mL of water was refluxed for 5 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding
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L.-L. Liang et al. / Journal of Molecular Structure 1006 (2011) 87–90 Table 1 Crystallographic data for complexes 1–3.
Fig. 1. Structures of the cucurbit[n]urils.
colorless crystals within 5 days (39% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C30H50N20O20Cd2KCl5 (%): C, 24.82, H, 3.47, N, 19.29; found: C, 25.17, H, 3.38, N, 19.40. 2.3. Preparation of 2{[Ca(H2O)(OH)]-l-[Pr(H2O)3[Cl@Q[5]]]}3+ 6Cl32H2O (2) The single crystal of the complex 2 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), CaCl2 (22 mg, 0.20 mmol) and PrCl3 (74 mg, 0.30 mmol) in 10 mL of water was refluxed for 30 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding colorless crystals within 7 days (51% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C60H146N40O64Pr2Ca2Cl8 (%): C 23.26, H 4.75, N 18.09; found: C 23.57, H 4.61, N 18.23. 2.4. Preparation of {[Nd(H2O)3][(NO3)@Q[5]][K(H2O)][Nd(H2O)3 (NO3)4]}2+2(NO3)8H2O (3) The single crystal of the compound 3 was obtained by dissolving a mixture of Q[5]10H2O (50 mg, 0.05 mmol), KCl (15 mg, 0.20 mmol) and Nd(NO3)3 (99 mg, 0.30 mmol) in 10 mL of water was refluxed for 30 min and then filtered, the filtrate was allowed to stand slow evaporation in air at room temperature, yielding magenta crystals within 8 days (56% yield on the basis of Q[5]10H2O). Elemental analysis calcd. for C30H60N27O46Nd2K (%): C 19.35, H 3.25, N 20.30; found: C 19.27, H 3.18, N 20.40. 2.5. Crystallography The data of the four supramolecular assemblies were collected on a Bruker Apex-2000 CCD diffractometer using graphite monochromated Mo Ka radiation (k = 0.71073 Å) in x scan mode. Lorentz polarization and absorption corrections were applied. Structural solution and full matrix least-squares refinement based on F2 were performed with the SHELXS-97 and SHELXL-97 program package [18,19], respectively. All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were generated geometrically. Details of the crystal parameters, data collection, and refinements for complexes 1–3 are summarized in Table 1. Further details are provided in the Supporting information. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as deposition Nos.: CCDC 820002 (1), CCDC 820003 (2), CCDC 820004 (3). Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223/336 033; [email protected]). 3. Results and discussion 3.1. Crystal structure of {(CdCl)[K(H2O)][Cl@Q[5]]}+[CdCl3 (H2O)2]7H2O (1) The X-ray structure of 1 reveals a one dimensional supramolecular chain constructed of heterometallic cadmium and potassium ions/cucurbit[5]uril capsules through the hydrogen bonding. The
a b
Compound
1
2
3
Empirical formula Formula weight Crystal system Space group a (Å) b (Å) c (Å) a (°) b (°) c (°) V (Å3) Z k (Å) Dcalcd. (g cm3) T (K) Unique reflns Obsd reflns Params Rint R [I > 2r(I)]a wR[I > 2r(I)]b
C30H50N20O20Cd2KCl5 C60H146N40O64Pr2Ca2Cl8 C30H60N27O46Nd2K 1452.02
3097.75
1862.63
Orthorhombic
Monoclinic
Triclinic
P212121 12.0196(16) 16.529(2) 24.768(3) 90.00 90.00 90.00 4920.7(11) 4 0.71073 1.960
C 2/m 24.146(2) 15.1185(13) 34.302(3) 90.00 108.377(2) 90.00 11883.6(18) 4 0.71073 1.731
P-1 12.0577(8) 13.8132(10) 18.3926(13) 88.412(2) 82.692(2) 88.700(2) 3036.8(4) 2 0.71703 2.037
223 8643 8252 703 0.0309 0.0313 0.0831
223 11804 10495 899 0.0281 0.0547 0.1506
223 11541 10486 956 0.0406 0.0516 0.1432
Conventional R on Fhkl: R||Fo| |Fc||/R|Fo|. Weighted R on |Fhkl|2: R½wðF 2o F 2c Þ2 =R½wðF 2o Þ2 1=2 .
capsule is fully capped by cadmium and potassium cations at its two portals (referring to Fig. 2a). Both of cation Cd1 and K1 coordinated to seven atoms: for the Cd cation, five carbonyl oxygens (O1, O2, O3, O4, and O5); a chloride anion (Cl1) at a portal of Q[5]; an included chloride anion (Cl2) shared with potassium cation at other portal of the Q[5]. For the K1 cation, five carbonyl oxygens (O6, O7, O8, O9, and O10); a water molecule (O10W) at the other portal of Q[5]; an included chloride anion (Cl2) shared with cadmium cation at the portal of the Q[5]. The distances between the capped ion Cd1 and carbonyl oxygens of Q[5] are 2.567(4) Å (Cd1–O1), 2.491(4) Å (Cd1–O2), 2.683(5) Å (Cd1–O3), 2.534(5) Å (Cd1–O4), 2.512(5) Å (Cd1–O5), the average distance is 2.557 Å. The distances between the capped ion Cd1 and the coordinated Cl1 anion at the portal is 2.445 Å. The distances between the capped ion K1 and carbonyl oxygens of Q[5] are 2.765(4) Å (K1–O6), 2.654(4) Å (K1–O7), 2.661(5) Å (K1–O8), 2.762(5) Å (K1–O9), 2.660(5) Å (K1–O10), the average distance is 2.701 Å. The distances between the capped ion K1 and the coordinated water molecule (O3W) is 2.751 Å. The distances between the capped ion Cd1 or K1 and the included Cl2 anion is 2.469 and 3.550 Å respectively. The neighboring capsules are linked by the coordinated water molecules (O3W) and two latticed water molecules O5W and O7W through hydrogen binding of O2–O7W–O7 (O2–O7W, 2.828 Å and O7W–O7, 2.762 Å); O3W–O3 (2.933 Å) and O8–O5W–O4 (O8–O5W, 2.825 Å and O5W–O4, 2.956 Å). Thus, a 1D supramolecular chain is formed (referring to Fig. 2b). Remarkably, the supramolecular chains arranged in a honeycomb structure with linear hexagonal channels extended along the a axis in 1 (referring to Fig. 2c) [20]. Each channel constructed of six paralleled supramolecular chains has an around 11.6 Å 8.8 Å section, and is filled with [Cd(H2O)2Cl3] complex anions (referring to Fig. 2d and e). The included [Cd(H2O)2Cl3] anions interact with the coordinated and latticed water molecules and discrete chloride anions through hydrogen bonding interaction, that leads to the formation of a complicated non-covalent interaction network. The channels or the void constructed of the wall of the cucurbit[5]uril appear to favor including or containing larger anions. In our recent work, we have demonstrated the ring with eight interlinked Q[5]
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Fig. 2. X-ray crystal structure of (a) the heterometallic metal ions/cucurbit[5]uril capsule; (b) the 1D supramolecular chain based on the capsules; (c) view of honeycomb structure with linear channels extended along the a axis; view of a hexagonal channel filled with [Cd(H2O)2Cl3], (d) top view, (e) side view.
‘‘beads’’ including four large anion InCl4 [13]. A more recent study 2 also showed that large anions ZnCl4 can be contained in the channels constructed of the walls of the Q[5]s, instead of including in the cavity of the Q[n]s [6]. 3.2. Crystal structure of 2{Ca(H2O)2(OH)-l-[Pr(H2O)3Cl@Q5]} 6Cl32(H2O) (2) The X-ray structure of 2 reveals a novel heterometallic cucurbit[5]uril pair, in which two Q[5] molecules are linked by a [Ca2(l-H2O)2(H2O)2] unit through direct coordination of calcium to portal carbonyl of the Q[5]s. while the other opening portal of the two Q[5] molecules in the unit is fully capped by praseodymium cations (referring to Fig. 3a). The Ca1 cation coordinates to nine oxygen atoms: four carbonyl oxygens belong to two Q[5] molecules in the unit (O4, O5, and O10, O11); two water molecules (O5W, O6W), which are shared with another Ca1 cation in the unit; two water molecules O7W and O8W (both of them with a 50% occupancy). The Pr1 or Pr2 cation also coordinates to nine atoms: five carbonyl oxygens (2O1, 2O2 and O3 or 2O7, 2O8 and O9); three coordinated water molecule (2O1W and O2W or O3W and 2O4W); an included chloride anion (Cl1 or Cl2) respectively. The distances between the capped ion Ca1 and carbonyl oxygens of two Q[5]s are 2.448 Å (Ca1–O4), 2.413 Å (Ca1–O5), 2.442 Å
(Ca1–O10), 2.432 Å (Ca1–O11), respectively, the average distance is 2.444 Å. The distances between the capped ion Ca1 and the coordinated water molecules are in the range of 2.406–2.497 Å. The distances between the capped ion Pr1 or Pr2 and carbonyl oxygens of Q[5] are 2.517 Å (Pr1–O1), 2.587 Å (Pr1–O2) and 2.535 Å (Pr1– O3), or 2.538 Å (Pr2–O7), 2.542 Å (Pr2–O8) and 2.519 Å (Pr2–O9), respectively, the average distance is 2.540 Å. The distances between the capped ion Pr1 or Pr2 and the coordinated water molecules are 2.573 Å (Pr1–O1W) and 2.566 Å (Pr1–O2W) or 2.568 Å (Pr2–O3W) and 2.535 Å (Pr2–O4W), respectively, the average distance is 2.561 Å. The distance between Pr1 or Pr2 and the included chloride anion Cl1 or Cl2 is 2.778 Å or 2.794 Å. It is common that larger cucurbit[n]urils, such as Q[6], Q[7] or Q[8], which have larger portals, could be capped with two or three metal ions at one portal [5,20,21]. To our knowledge, it is the first several Q[5]–metal complexes, in which a portal of a Q[5] molecule is capped with two metal ions [22]. In the present case, the Ca2+ and Pr3+ cations have similar ionic diameters, 0.99 Å and 1.01 Å respectively. When the Pr3+ cation fully coordinates on a portal of a Q[5] molecule, the other portal of the Q[5] molecule could be enlarged. The average distances of the center of five portal oxygen to these portal oxygens are 2.686 Å (Ca2+ capped) and 2.480 Å Pr3+ capped) respectively, there is 0.2 Å difference (referring to Fig. 3b). It suggests that the portal is too large to be fully capped
Fig. 3. X-ray crystal structure of (left) the heterometallic metal ions/cucurbit[5]uril pair linked by a [Ca2(l-H2O)2(H2O)2] unit; (b) the portal size data of a heterometallic Pr3+ and Ca2+ metal ions/cucurbit[5]uril complex.
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into a metal–Q[5] system, it could lead to the formation of a new novel Q[5]-based architecture. When a K–Q[5] system is introduced CdCl2 salt, the X-ray structure of 1 reveals a honeycomb structure constructed of one dimensional supramolecular chain of the heterometallic cadmium and potassium ions/cucurbit[5]uril capsules; when a Pr–Q[5] system is introduced CaCl2 salt, the first several Q[5]–metal complexes, in which a portal of a Q[5] molecule is capped with two metal ions, can be obtained. The strategy of introduction of a third species into a metal–Q[n] system could results in the formation of a novel Q[n]-based architecture, and we are at present embarking on studies of this type. Fig. 4. X-ray crystal structure of the heterometallic Nd3+ and K+ metal ions/ cucurbit[5]uril capsule and a linked [Nd(H2O)3(NO3)4] complex.
by one metal ion, which has a similar ionic diameter, such as the calcium ion. Thus, [Ca2(l-H2O)2(Cl)2] units capped on the portals of Q[5]s in the Q[5] pair can be observed in 2. 3.3. Crystal structure of {[Nd(H2O)3][(NO3)@Q[5]][K(H2O)][Nd(H2O)3(NO3)4]}2+2(NO3)8H2O (3)
Acknowledgments We thank the National Natural Science Foundation of China (NSFC; No. 20961002 and 20971002), Natural Science Foundation of the Education Department of Guizhou Province, the Science and Technology Fund of Guizhou Province, and the International Collaborative Project Fund of Guizhou province for the financial support. Appendix A. Supplementary material
The X-ray structural analysis reveals discrete heterometallic neodymium and potassium/cucurbit[5]uril capsules in 3. In each capsule, the K1 cation coordinates to ten oxygen atoms: five carbonyl oxygens (O6, O7, O8, O9 and O10); one water molecule (O3W); two oxygens (O11 and O12) of a coordinated nitrate anion at the portal; two oxygens (O29 and O30) of an included nitrate anion in the cavity of the Q[5] molecule. The Nd1 cation coordinates to nine oxygen atoms: five carbonyl oxygens (O1, O2, O3, O4 and O5); three coordinated water molecule (O4W, O5W and O6W); one of three oxygens (O31) of the included nitrate anion in the cavity of the Q[5] molecule. Compared to the average distance (2.701 Å) of K1–O(carbonyl) in 1, the average distance between the capped ion K1 and carbonyl oxygens is 2.783 Å in 3, slightly longer than that in 1. The distances between the capped ion Nd1 and carbonyl oxygens of Q[5] are in the range of 2.511–2.570 Å, similar to those of Pr–O(carbonyl) in 2. The distances between the capped ion K1 and the coordinated water molecule (O6W) is 3.257 Å. The distances between the capped ion Nd1 and the coordinated water molecule are 2.472 Å (Nd1–O5W), 2.482 Å (Nd1– O7W) and 2.448 Å (Nd1–O8W), respectively. The distances between the included nitrate anion and the two capped cation ions are 3.181 Å (K1–O31) and 2.983 Å (K1–O30) and 2.374 Å (Nd– O29), respectively. In additional, a [Nd(H2O)3(NO3)4] anion complex linked to the molecular capsule through the coordination the K1 cation to one of nitrate anion in the anion complex (see Fig. 4). 4. Conclusion In the present study, three heterometallic metal ions/Q[5] systems are introduced. When the second inorganic salt is introduced
Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.molstruc.2011.07.062. References [1] Review: J. Lagona, P. Mukhopadhyay, S. Chakrabarti, L. Isaacs, Angew. Chem., Int. Ed. 44 (2005) 4844. [2] K.M. Park, S.Y. Kim, J. Heo, D. Whang, S. Sakamoto, K. Yamaguchi, K. Kim, J. Am. Chem. Soc. 124 (2002) 2140. [3] H. Cong, Q.J. Zhu, S.F. Xue, Z. Tao, G. Wei, Chin. Sci. Bull. 55 (2010) 3633. [4] P. Thuery, Cryst. Growth Des. 9 (2009) 1208. [5] P. Thuery, Inorg. Chem. 48 (2009) 825. [6] X. Xiao, K. Chen, S.F. Xue, Q.J. Zhu, Z. Tao, G. Wei, J. Mol. Struct. 969 (2010) 216. [7] J.X. Liu, Y.F. Gu, R.L. Lin, W.R. Yao, X.H. Liu, J. Zhu, Supramol. Chem. 22 (2010) 130. [8] R. Hernandez-Molina, M.N. Sokolov, A.G. Sykes, Acc. Chem. Res. 34 (2001) 223. [9] V.P. Fedin, Russ. Chem. Bull. 52 (2003) 1041. [10] R. Hernandez-Molina, M. Sokolov, P. Esparza, C. Vicent, R. Llusar, Dalton (2004) 847. [11] R. Hernandez-Molina, M.N. Sokolov, M. Clausen, W. Clegg, Inorg. Chem. 45 (2006) 10567. [12] O.A. Gerasko, E.A. Mainicheva, M.I. Naumova, M. Neumaier, M.M. Kappes, S. Lebedkin, D. Fenske, V.P. Fedin, Inorg. Chem. 47 (2008) 8869. [13] X.L. Ni, J.X. Lin, Y.Y. Zheng, W.S. Wu, Y.Q. Zhang, S.F. Xue, Q.J. Zhu, Z. Tao, A.I. Day, Cryst. Growth Des. 8 (2008) 3446. [14] Z.F. Li, F. Wu, F.G. Zhou, X.L. Ni, X. Feng, X. Xiao, Y.Q. Zhang, S.F. Xue, Q.J. Zhu, L.F. Lindoy, J.K. Clegg, Z. Tao, G. Wei, Cryst. Growth Des. 10 (2010) 5113. [15] J.X. Liu, L.S. Long, R.B. Huang, L.S. Zheng, Cryst. Growth Des. 6 (2006) 2611. [16] J. Kim, I.S. Jung, S.Y. Kim, E. Lee, J.K. Kang, S. Sakamoto, K. Yamaguchi, K. Kim, J. Am. Chem. Soc. 122 (2000) 540. [17] A.I. Day, A.P. Arnold, WO 0068232, 2000, p. 8. [18] G.M. Sheldrick, Acta Crystallogr. A 46 (1990) 467. p. 423. [19] G.M. Sheldrick, SHELXL-97 Program for the Solution and Refinement of Crystal Structures, University of Göttingen, Germany, 1997. [20] J.X. Liu, C.H. Dong, L.S. Long, R.B. Huang, L.S. Zheng, Dalton Trans. 36 (2009) 7344. [21] J. Heo, S.Y. Kim, D. Whang, K. Kim, Angew. Chem., Int. Ed. 38 (1999) 641. [22] Y.Q. Zhang, J.P. Zeng, Q.J. Zhu, S.F. Xue, Z. Tao, J. Mol. Struct. 929 (2009) 167.