- Email: [email protected]
Extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters
Inorganic Chemistry Communications 23 (2012) 70–73
Contents lists available at SciVerse ScienceDirect
Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche
Extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters Shuang Yao a,⁎, Jinghui Yan a, Yanchun Yu a, Enbo Wang b a b
College of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Wei Xing Road No.7989, Changchun, Jilin, 130022, PR China Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Ren Min Street No.5268, Changchun, Jilin, 130024, PR China
a r t i c l e
i n f o
Article history: Received 8 February 2012 Accepted 12 June 2012 Available online 22 June 2012 Keywords: Heterometal Silicotungstate Tetrameric Extended architectures
a b s t r a c t Two extended architectures, Na2[Cu(en)2]9{K4Na2[Dy(SiW11O39)2]2}·32H2O (1), K2[Cu(en)2]9{K4Na2[Ho(SiW11O39)2]2}·41H2O (2) (en= ethylenediamine), have been successfully synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction analysis, element analysis, IR spectroscopy, thermal gravimetric analysis and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis revealed that both 1 and 2 contain a tetrameric polyoxoanions, consisting of four {α-SiW11O39} building blocks, two lanthanide cations, a {K4Na2} linking fragment and four decorating [Cu(en)2]2+ groups. Interestingly, the tetrameric polyoxoanions in 1 and 2 are bridged into a one dimensional (1D) infinite chain by additional [Cu(en)2]2+ bridges. © 2012 Elsevier B.V. All rights reserved.
Polyoxometalates (POMs), a unique class of metal-oxygen cluster complexes, have been used in numerous fields, such as catalysis, magnetochemistry, photochemistry, materials science, and medicine, as their remarkable structures and properties [1–3]. In the past decades, design and synthesis of multinuclear transition-metal (TM) substituted POMs has received much of its impetus from their intriguing variety of architectures and their fascinating chemical and physical properties [4,5]. Simultaneously, lanthanide (Ln) cations, because of their multiple coordination requirements and oxophilicity, are suitable to incorporate with POMs to form functional materials with potential applications in magnetism and optics [6,7]. As a result, lots of such multinuclear TM or Ln-substituted POMs have hitherto been reported, which have been regarded as an important family of POM chemistry. In comparison to the extensive work on the TM or Ln-substituted POMs, considerably less attention has been paid on the 3d–4f heterometallic POMs [8–12]. In the reaction, the reaction competitions in 3d–4f-POM synthetic systems among the highly negative polyoxoanions, Ln cations and TM cations appears to be one of the key factors behind the low number of heterometallic clusters reported [8]. Interestingly, Kögerler et al. reported two heterometallic POMs by reactions of the lacunary polyoxoanions with the preformed heterometallic clusters [CeIV3MnIV2O6(OH)2]6+ and [CeMn6O9(O2CCH3)9(NO3)(H2O)2], which have successfully avoided competition among the highly negative polyoxoanions, Ln cations and TM cations [9]. Meanwhile, Mialane's group reported the magnetic {LnCu3(OH)3H2O} cubane-containing POMs by reaction of the [A-α-SiW9O34]10− unit with the Cu2+, Ln3+ in the presence of adapted exogenous ligands [10]. Very recently, ⁎ Corresponding author. Tel.: + 86 431 85583142; fax: + 86 431 85383815. E-mail address: [email protected] (S. Yao). 1387-7003/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2012.06.010
two dimeric polyoxoanions [{Ce(H2O)2}2Mn2(B-α-GeW9O34)2] 8− and [{CeIV(OAc)}CuII3(H2O)(B-α-GeW9O34)2] 11− were isolated by Reinoso and his co-workers [11]. In the past two years, Niu et al. reported several organic–inorganic hybrids assembled from [Ln(α-PW11O39)2] 11− polyoxoanions and copper linkers [12]. We have worked in this field for a long time, and reported a series of 3d and 4f heterometals-containing POMs [13]. In this paper, two extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters were isolated under hydrothermal conditions by introducing the exogenous ligands into 3d–4f-POM reaction systems. Compounds 1 and 2 were synthesized by reactions of the monovacant POMs K8[β2-SiW11O39]•14H2O, Cu(NO3)2, Ln3+ ions and the exogenous ligands en under hydrothermal conditions. Single crystal X-ray diffraction analysis reveal that polyoxoanions 1 and 2 are isostructural and crystallize in the same space group P2(1)/n. Therefore, only the structure of 1 is described in detail. As shown in Fig. 1, polyoxoanion 1 exhibits 1D chain-like structures built up of a tetrameric aggregate {K4Na2[Dy(SiW11O39)2]2}11− and [Cu(en)2] 2+ groups. In the 1D chain, the tetrameric aggregate is composed of four [α-SiW11O39] units which possess a monovacant α-Keggin structural feature, resulting by removal of one [WO6] octahedron from the saturated α-Keggin structure (Figure. S1). Two neighboring [α-SiW11O39] units are fused together by a octa-coordinated Dy(III) cation with the bond length of 2.34(2)– 2.42(2) Å, resulting in a sandwich-type silicotungstate cluster [Dy(SiW11O39)2] (Figs. 2 and S1). Interestingly, the sandwich-type structure was decorated by two Cu 2+ cations (Cu(3) and Cu(4)) (Fig. 2), which are in the penta- and hexa-coordinated environment, respectively. The Cu(3) 2+ cation displays the square pyramid geometry defined by for N atoms from two en ligands [Cu–N, 1.96(2)–1.98(2) Å] and one terminal O atom from the [Dy(α-SiW11O39)2] moiety [Cu–O,
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73
71
Fig. 1. Polyhedral and ball‐ and ‐stick representation of 1D chain in 1.
2.396(18) Å]. The Cu(4) 2+ cation adopts the octahedral coordination configuration, which was completed by four N atoms from two en ligands [Cu–N, 1.98(2)–2.039(19) Å], one water ligand [Cu–Ow, 2.473 Å] and one terminal O atom from the [Dy(α-SiW11O39)2] moiety [Cu–O, 2.775 Å]. Additionally, two adjacent sandwich polyoxoanions [Dy(SiW11O39)2] are bridged by a [K4Na2] group into a tetrameric aggregate (Figs. 2 and S2). In 1, each tetrameric aggregate connects with two [Cu(5)(en)2] 2+ units, and each [Cu(5)(en)2] 2+ unit bridges to two tetrameric aggregates resulting in an infinite 1D chain running along the a-axis (Fig. 1). In this polymeric chain, the Cu(5)2+ cation coordinates to two tetrameric aggregates by two bridging oxygen atoms and links them to constitute the 1D chain with Cu\O bond lengths of 2.571(22) Å, while the four remaining octahedral coordination sites of Cu(5) 2+ are occupied by four N atoms from two en molecules with Cu\N bond lengths ranging from 1.99 (2) to 2.011 (18) Å. In this field, the sandwich-type polyoxoanions mostly provide terminal oxygen atoms to combine with the linkers forming the extended structural materials. The sandwich-type polyoxoanion coordinating with the linking groups via bridging oxo-atoms is rarely observed in the POM chemistry [14]. The bond lengths and angles in the two compounds are not unusual. All the W centers exhibit octahedral coordination environments and the Ln3+ ions in the two compounds are all in an octacoordinated fashion. The oxidation states of the W, Cu and Ln sites are determined based on the bond lengths and angles, charge balance consideration and bond valence sum calculations, indicating that all W, Cu, Dy and Ho atoms in 1 and 2 are in the +6, +2, +3 and +3 oxidation state, respectively. Bond valence sum calculations also reveal
Fig. 2. Polyhedral and ball‐ and ‐stick representation of the tetrameric aggregate in 1.
that the terminal oxygen atoms associated with the Cu 2+ ions are all diprotonated. The solid-state magnetic behaviors of 1 and 2 were measured in the temperature range of 2.0–300 K at a 0.1 T magnetic field (Figs. 3 and 4), and was plotted as χT versus T. As shown in Fig. 3, χT value slowly decreases from 16.7 cm3 K mol− 1 at room temperature to 16.0 cm3 K mol− 1 at 55 K, and then rapidly drops to a value of 12.1 cm3 K mol− 1 at 2 K. The χ− 1 versus T plot is fitted by the Curie–Weiss law in the whole temperature range with C = 16.83 cm3·K·mol− 1 and Ө = −5.43 K. The χT value of 1 is 16.7 cm 3 K mol − 1 at room temperature, which is a little lower than that of the expected values for nine Cu 2+ (S = 1/2) and one Dy III noninteracting ions: 17.5 cm 3 K mol − 1 for 1 (Dy III: 6 H15/2, S = 5/2, L = 5, g = 4/3, C = 14.17 cm 3 K mol − 1). For compound 2, χT value slowly decreases from 17.5 cm3 K mol− 1 at 300 K to 16.8 cm3 K mol− 1 at 55 K, and then rapidly drops to a value of 9.8 cm3 K mol− 1 at 2 K. The χ− 1 versus T plot is fitted by the Curie– Weiss law in the whole temperature range with C =17.6 cm3·K·mol− 1 and Ө = −6.49 K. The χT value of 2 is 17.6 cm3 K mol− 1 which is a reasonably agreement with the expected values for nine Cu2+ (S = 1/2) and one HoIII noninteracting ions: 17.43 cm3 K mol− 1 (HoIII: S = 2, L = 6, g= 5/4, C= 14.06 cm3·K·mol − 1). The χT value slowly decreases upon lowing the temperature of the two compounds may result from spin-orbit coupling of lanthanide ion. In conclusion, two 1D chain-like structures built upon 3d–4f heterometals-containing silicotungstates have been obtained by the reactions of K8[β2-SiW11O39]·14H2O, Dy 3+, and Cu 2+ with the assistance of organic ligands under hydrothermal conditions. The chainlike structures in 1 and 2 provide novel examples of condensation of discrete clusters through TM and Ln cations into extended structures. Future research will focus on the synthesis of 3D porous framework
Fig. 3. Temperature dependence of (a) χ and (b) χT values and (inset) temperature dependence of reciprocal magnetic susceptibility χ− 1 for 1.
72
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73
Fig. 4. Temperature dependence of (a) χ and (b) χT values and (inset) temperature dependence of reciprocal magnetic susceptibility χ− 1 for 2.
materials based on the Ln-containing sandwich-type polyoxoanions and other TM cations. This work is ongoing in our group. Acknowledgments This work was supported by the National Natural Science Foundation of China (21101022). Appendix A. Supplementary data The experiments in detail, crystal data, IR spectra, TG curves, XRD pattern, additional figures and X-ray crystallographic information file (CIF) are available for compounds 1 and 2. Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.inoche.2012. 06.010. References [1] (a) A. Müller, F. Peters, M.T. Pope, D. Gatteschi, Polyoxometalates: very large clusters nanoscale magnets, Chem. Rev. 98 (1998) 239–271; (b) P. Mialane, A. Dolbecq, F. Sécheresse, Functionalization of polyoxometalates by carboxylato and azido ligands: macromolecular complexes and extended compounds, Chem. Commun. 33 (2006) 3477–3485; (c) C. Pichon, P. Mialane, E. Rivière, G. Blain, A. Dolbecq, J. Marrot, F. Sécheresse, C. Duboc, The highest D Value for a MnII ion: investigation of a manganese(II) polyoxometalate complex by high-field electron paramagnetic resonance, Inorg. Chem. 46 (2007) 7710–7712; (d) D.L. Long, E. Burkholder, L. Cronin, Polyoxometalate clusters, nanostructures and materials: from self assembly to designer materials and devices, Chem. Soc. Rev. 36 (2007) 105–121. [2] (a) J.M.C. Juan, E. Coronado, Magnetic clusters from polyoxometalate complexes, Coord. Chem. Rev. 193–195 (1999) 361–394; (b) J.T. Rhule, C.L. Hill, D.A. Judd, R.F. Schinazi, Polyoxometalates in medicine, Chem. Rev. 98 (1998) 327–357; (c) A. Proust, R. Thouvenot, P. Gouzerhg, Functionalization of polyoxometalates: towards advanced applications in catalysis and materials science, Chem. Commun. 16 (2008) 1837–1852; (d) S.T. Zheng, J. Zhang, G.Y. Yang, Designed synthesis of POM-organic frameworks by Ni6PW9 building blocks under hydrothermal conditions, Angew. Chem. Int. Ed. 47 (2008) 3909–3913; (e) L.X. Shi, X.W. Zhang, C.D. Wu, The synergistic effect of [WZn(VO)2(ZnW9O34)2]12− cores and peripheral metal sites in catalytic oxidative cyclization of acetylacetone, Dalton Trans. 40 (2011) 779–781. [3] (a) C. Ritchie, A. Ferguson, H. Nojiri, H.N. Miras, Y.F. Song, D.L. Long, E. Burkholder, M. Murrie, P. Kögerler, E.K. Brechin, L. Cronin, Polyoxometalate-mediated self-assembly of single-molecule magnets: {[XW9O34]2[MnIII4MnII2O4(H2O)4]}12−, Angew. Chem. Int. Ed. 47 (2008) 5609–5612; (b) A.E. Kuznetsov, Y.V. Geletii, C.L. Hill, K. Morokuma, D.G. Musaev, Dioxygen and water activation processes on multi-Ru-substituted polyoxometalates: comparison with the “Blue-dimer” water oxidation catalyst, J. Am. Chem. Soc. 131 (2009) 6844–6854; (c) M.A. AlDamen, J.M. Clemente-Juan, E. Coronado, C. Martí-Gastaldo, A. Gaita-Ariño, Mononuclear lanthanide single-molecule magnets based on polyoxometalates, J. Am. Chem. Soc. 130 (2008) 8874–8875;
(d) D. Barats, G. Leitus, R. Popovitz-Biro, L.J.W. Shimon, R. Neumann, A stable “End-On” iron(III)–hydroperoxo complex in water derived from a multi-iron(II)-substituted polyoxometalate and molecular oxygen, Angew. Chem. Int. Ed. 47 (2008) 9908–9912; (e) F.P. Xiao, J. Hao, J. Zhang, C.L. Lv, P.C. Yin, L.S. Wang, Y.G. Wei, Polyoxometalatocyclophanes: controlled assembly of polyoxometalate-based chiral metallamacrocycles from achiral building blocks, J. Am. Chem. Soc. 132 (2010) 5956–5957. [4] (a) R. Copping, A.J. Gaunt, I. May, C.A. Sharrad, D. Collison, M. Helliwell, O.D. Foxc, C.J. Jones, Oxoneptunium(V) as part of the framework of a polyoxometalate, Chem. Commun. 36 (2006) 3788–3790; (b) L.H. Bi, U. Kortz, S. Nellutla, A.C. Stowe, J. van Tol, N.S. Dalal, B. Keita, L. Nadjo, Structure, electrochemistry, and magnetism of the iron(III)-substituted Keggin dimer, [Fe6(OH)3(A-α-GeW9O34(OH)3)2]11−, Inorg. Chem. 44 (2005) 896–903; (c) L. Li, Q. Shen, G. Xue, H. Xu, H. Hu, F. Fu, J. Wang, Two sandwich arsenomolybdates 9− based on the new building block As(III)Mo7O27 : [Cr2(AsMo7O27)2]12− and [Cu2(AsMo7O27)2]14−, Dalton Trans. 42 (2008) 5698–5700; (d) Z.M. Zhang, J. Liu, E.B. Wang, C. Qin, Y.G. Li, Y.F. Qi, X.L. Wang, Two extended structures constructed from sandwich-type polyoxometalates functionalized by organic amines, Dalton Trans. 4 (2008) 463–468. [5] (a) S.S. Mal, U. Kortz, The wheel-shaped Cu20 tungstophosphate [Cu20Cl(OH)24 (H2O)12(P8W48O184)]25− ion, Angew. Chem. Int. Ed. 44 (2005) 3777–3780; (b) B. Godin, Y.G. Chen, J. Vaissermann, L. Ruhlmann, M. Verdaguer, P. Gouzerh, Coordination chemistry of the hexavacant tungstophosphate [H2P2W12O48]12− with FeIII ions: towards original structures of increasing size and complexity, Angew. Chem. Int. Ed. 44 (2005) 3072–3075; (c) G.S. Kim, H.D. Zeng, D. VanDerveer, C.L. Hill, A supramolecular tetra-Keggin polyoxometalate [Nb4O6(− Nb3SiW9O40)4]20−, Angew. Chem. Int. Ed. 38 (1999) 3205–3207; (d) C.P. Pradeep, D.L. Long, P. Kögerlerb, L. Cronin, Controlled assembly and solution observation of a 2.6 nm polyoxometalate ‘super’ tetrahedron cluster: [KFe12(OH)18(α-1,2,3-P2W15O56)4]29−, Chem. Commun. 41 (2007) 4254–4256. [6] (a) B.S. Bassil, M.H. Dickman, I. Römer, B.V.D. Kammer, U. Kortz, The tungstogermanate [Ce20Ge10W100O376(OH)4(H2O)30]56−: a polyoxometalate containing 20 cerium(III) atoms, Angew. Chem. Int. Ed. 46 (2007) 6192–6195; (b) F. Hussain, R.W. Gable, M. Speldrich, P. Kögerler, C. Boskovic, Polyoxotungstate-encapsulated Gd6 and Yb10 complexes, Chem. Commun. 3 (2009) 328–330; (c) A. Sartorel, M. Carraro, G. Scorrano, R.D. Zorzi, Polyoxometalate embedding of a tetraruthenium(IV)-oxo-core by template-directed metalation of [γ-SiW10O36]8−: a totally inorganic oxygen-evolving catalyst, J. Am. Chem. Soc. 130 (2008) 5006–5007; (d) K. Fukaya, T. Yamase, Alkali-metal-controlled self-assembly of crown-shaped ring complexes of lanthanide/[α-AsW9O33]9−: [K⊂{Eu(H2O)2(α-AsW9O33)}6]35− and [Cs⊂{Eu(H2O)2(α-AsW9O33)}4]23−, Angew. Chem. Int. Ed. 42 (2003) 654–658. [7] (a) K. Wassermann, M.H. Dickman, M.T. Pope, Self-assembly of supramolecular polyoxometalates: the compact water-soluble heteropolytungstate anion [AsCe(H2O)36W148O524]76−, Angew. Chem. Int. Ed. Engl. 36 (1997) 1445–1448; (b) F. Hussain, F. Conrad, G.R. Patzke, A gadolinium-bridged polytungstoarsenate(III) nanocluster: [Gd8As12W124O432(H2O)22]60−, Angew. Chem. Int. Ed. 48 (2009) 9088–9091. [8] S. Reinoso, Heterometallic 3d–4f polyoxometalates: still an incipient field, Dalton Trans. 40 (2011) 6610–6615. [9] (a) X.K. Fang, P. Kögerler, PO43−-mediated polyoxometalate supercluster assembly, Angew. Chem. Int. Ed. 47 (2008) 8123–8126; (b) X.K. Fang, P. Kögerler, A polyoxometalate-based manganese carboxylate cluster, Chem. Commun. 29 (2008) 3396–3398. [10] (a) B. Nohra, P. Mialane, A. Dolbecq, E. Rivière, J. Marrot, F. Sécheresse, Heterometallic 3d–4f cubane clusters inserted in polyoxometalate matrices, Chem. Commun. 19 (2009) 2703–2705; (b) J.D. Compain, P. Mialane, A. Dolbecq, I.M. Mbomekallé, J. Marrot, F. Séecheresse, C. Duboc, E. Rivière, Structural, magnetic, EPR, and electrochemical characterizations of a spin-frustrated trinuclear CrIII polyoxometalate and study of its reactivity with lanthanum cations, Inorg. Chem. 49 (2010) 2851–2858. [11] (a) S. Reinoso, J.R. Galán-Mascarós, Heterometallic 3d−4f polyoxometalate derived from the weakley-type dimeric structure, Inorg. Chem. 49 (2010) 377–379; (b) A. Merca, A. Müller, J. van Slageren, M. Läge, B. Krebs, Systematic study of the interaction between VIV centres and lanthanide ions MIII in well defined {VIV2MIII}{AsIIIW9O33}2 sandwich type clusters: part 1, J. Clust. Sci. 18 (2007) 711–719; (c) S. Reinoso, J.R.G. Mascarós, L. Lezama, New type of heterometallic 3d–4f rhomblike core in weakley-like polyoxometalates, Inorg. Chem. 19 (2011) 9587–9593. [12] (a) J.F. Cao, S.X. Liu, R.G. Cao, L.H. Xie, Y.H. Ren, C.Y. Gao, L. Xu, Organic–inorganic hybrids assembled by bis(undecatungstophosphate) lanthanates and dinuclear copper(II)–oxalate complexes, Dalton Trans. (2008) 115–120; (b) J.Y. Niu, S.W. Zhang, H.N. Chen, J.W. Zhao, P.T. Ma, J.P. Wang, 1-D, 2-D, and 3-D organic–inorganic hybrids assembled from Keggin-type polyoxometalates and 3d–4f heterometals, Cryst. Growth Des. 11 (2011) 3769–3777; (c) D.Y. Shi, L.J. Chen, J.W. Zhao, Y. Wang, P.T. Ma, J.Y. Niu, Two novel 2D organic– inorganic hybrid lacunary Keggin phosphotungstate 3d–4f heterometallic
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73 derivatives: [Cu(en)2]2H6[Ce(α-PW11O39)2]·8H2O and [Cu(dap)2(H2O)] [Cu(dap)2]4.5[Dy(α-PW11O39)2]·4H2O, Inorg. Chem. Commun. 14 (2011) 324–329; (d) D.Y. Du, J.S. Qin, S.L. Li, Y.Q. Lan, X.L. Wang, Z.M. Su, 3d–4f Heterometallic complexes for the construction of POM-based inorganic–organic hybrid compounds: from nanoclusters to one-dimensional ladder-like chains, Aust. J. Chem. 63 (2010) 1389–1395. [13] (a) S. Yao, Z.M. Zhang, Y.G. Li, Y. Lu, E.B. Wang, Z.M. Su, Two heterometallic aggregates constructed from the {P2W12}–based trimeric polyoxotungstates and 3d–4f heterometals, Cryst. Growth Des. 10 (2010) 135–139;
73
(b) Z.M. Zhang, Y.G. Li, S. Yao, E.B. Wang, Hexameric polyoxometalates decorated by six 3d–4f heterometallic clusters, Dalton Trans. 40 (2011) 6475–6479; (c) Z.M. Zhang, Y.G. Li, W.L. Chen, E.B. Wang, X.L. Wang, Two-dimensional (3, 6)-topological inorganic aggregate based on the sandwich-type polyoxometalate and lanthanide linkers, Inorg. Chem. Commun. 11 (2008) 879–882. [14] J.-W. Zhao, S.-T. Zheng, Z.-H. Li, G.-Y. Yang, Combination of lacunary polyoxometalates and high-nuclear transition-metal clusters under hydrothermal conditions: first 65·8 CdSO4-type 3-D framework built by hexa-CuII sandwiched polyoxotungstates, Dalton Trans. (2009) 1300–1306.
Contents lists available at SciVerse ScienceDirect
Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche
Extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters Shuang Yao a,⁎, Jinghui Yan a, Yanchun Yu a, Enbo Wang b a b
College of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Wei Xing Road No.7989, Changchun, Jilin, 130022, PR China Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Ren Min Street No.5268, Changchun, Jilin, 130024, PR China
a r t i c l e
i n f o
Article history: Received 8 February 2012 Accepted 12 June 2012 Available online 22 June 2012 Keywords: Heterometal Silicotungstate Tetrameric Extended architectures
a b s t r a c t Two extended architectures, Na2[Cu(en)2]9{K4Na2[Dy(SiW11O39)2]2}·32H2O (1), K2[Cu(en)2]9{K4Na2[Ho(SiW11O39)2]2}·41H2O (2) (en= ethylenediamine), have been successfully synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction analysis, element analysis, IR spectroscopy, thermal gravimetric analysis and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis revealed that both 1 and 2 contain a tetrameric polyoxoanions, consisting of four {α-SiW11O39} building blocks, two lanthanide cations, a {K4Na2} linking fragment and four decorating [Cu(en)2]2+ groups. Interestingly, the tetrameric polyoxoanions in 1 and 2 are bridged into a one dimensional (1D) infinite chain by additional [Cu(en)2]2+ bridges. © 2012 Elsevier B.V. All rights reserved.
Polyoxometalates (POMs), a unique class of metal-oxygen cluster complexes, have been used in numerous fields, such as catalysis, magnetochemistry, photochemistry, materials science, and medicine, as their remarkable structures and properties [1–3]. In the past decades, design and synthesis of multinuclear transition-metal (TM) substituted POMs has received much of its impetus from their intriguing variety of architectures and their fascinating chemical and physical properties [4,5]. Simultaneously, lanthanide (Ln) cations, because of their multiple coordination requirements and oxophilicity, are suitable to incorporate with POMs to form functional materials with potential applications in magnetism and optics [6,7]. As a result, lots of such multinuclear TM or Ln-substituted POMs have hitherto been reported, which have been regarded as an important family of POM chemistry. In comparison to the extensive work on the TM or Ln-substituted POMs, considerably less attention has been paid on the 3d–4f heterometallic POMs [8–12]. In the reaction, the reaction competitions in 3d–4f-POM synthetic systems among the highly negative polyoxoanions, Ln cations and TM cations appears to be one of the key factors behind the low number of heterometallic clusters reported [8]. Interestingly, Kögerler et al. reported two heterometallic POMs by reactions of the lacunary polyoxoanions with the preformed heterometallic clusters [CeIV3MnIV2O6(OH)2]6+ and [CeMn6O9(O2CCH3)9(NO3)(H2O)2], which have successfully avoided competition among the highly negative polyoxoanions, Ln cations and TM cations [9]. Meanwhile, Mialane's group reported the magnetic {LnCu3(OH)3H2O} cubane-containing POMs by reaction of the [A-α-SiW9O34]10− unit with the Cu2+, Ln3+ in the presence of adapted exogenous ligands [10]. Very recently, ⁎ Corresponding author. Tel.: + 86 431 85583142; fax: + 86 431 85383815. E-mail address: [email protected] (S. Yao). 1387-7003/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2012.06.010
two dimeric polyoxoanions [{Ce(H2O)2}2Mn2(B-α-GeW9O34)2] 8− and [{CeIV(OAc)}CuII3(H2O)(B-α-GeW9O34)2] 11− were isolated by Reinoso and his co-workers [11]. In the past two years, Niu et al. reported several organic–inorganic hybrids assembled from [Ln(α-PW11O39)2] 11− polyoxoanions and copper linkers [12]. We have worked in this field for a long time, and reported a series of 3d and 4f heterometals-containing POMs [13]. In this paper, two extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters were isolated under hydrothermal conditions by introducing the exogenous ligands into 3d–4f-POM reaction systems. Compounds 1 and 2 were synthesized by reactions of the monovacant POMs K8[β2-SiW11O39]•14H2O, Cu(NO3)2, Ln3+ ions and the exogenous ligands en under hydrothermal conditions. Single crystal X-ray diffraction analysis reveal that polyoxoanions 1 and 2 are isostructural and crystallize in the same space group P2(1)/n. Therefore, only the structure of 1 is described in detail. As shown in Fig. 1, polyoxoanion 1 exhibits 1D chain-like structures built up of a tetrameric aggregate {K4Na2[Dy(SiW11O39)2]2}11− and [Cu(en)2] 2+ groups. In the 1D chain, the tetrameric aggregate is composed of four [α-SiW11O39] units which possess a monovacant α-Keggin structural feature, resulting by removal of one [WO6] octahedron from the saturated α-Keggin structure (Figure. S1). Two neighboring [α-SiW11O39] units are fused together by a octa-coordinated Dy(III) cation with the bond length of 2.34(2)– 2.42(2) Å, resulting in a sandwich-type silicotungstate cluster [Dy(SiW11O39)2] (Figs. 2 and S1). Interestingly, the sandwich-type structure was decorated by two Cu 2+ cations (Cu(3) and Cu(4)) (Fig. 2), which are in the penta- and hexa-coordinated environment, respectively. The Cu(3) 2+ cation displays the square pyramid geometry defined by for N atoms from two en ligands [Cu–N, 1.96(2)–1.98(2) Å] and one terminal O atom from the [Dy(α-SiW11O39)2] moiety [Cu–O,
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73
71
Fig. 1. Polyhedral and ball‐ and ‐stick representation of 1D chain in 1.
2.396(18) Å]. The Cu(4) 2+ cation adopts the octahedral coordination configuration, which was completed by four N atoms from two en ligands [Cu–N, 1.98(2)–2.039(19) Å], one water ligand [Cu–Ow, 2.473 Å] and one terminal O atom from the [Dy(α-SiW11O39)2] moiety [Cu–O, 2.775 Å]. Additionally, two adjacent sandwich polyoxoanions [Dy(SiW11O39)2] are bridged by a [K4Na2] group into a tetrameric aggregate (Figs. 2 and S2). In 1, each tetrameric aggregate connects with two [Cu(5)(en)2] 2+ units, and each [Cu(5)(en)2] 2+ unit bridges to two tetrameric aggregates resulting in an infinite 1D chain running along the a-axis (Fig. 1). In this polymeric chain, the Cu(5)2+ cation coordinates to two tetrameric aggregates by two bridging oxygen atoms and links them to constitute the 1D chain with Cu\O bond lengths of 2.571(22) Å, while the four remaining octahedral coordination sites of Cu(5) 2+ are occupied by four N atoms from two en molecules with Cu\N bond lengths ranging from 1.99 (2) to 2.011 (18) Å. In this field, the sandwich-type polyoxoanions mostly provide terminal oxygen atoms to combine with the linkers forming the extended structural materials. The sandwich-type polyoxoanion coordinating with the linking groups via bridging oxo-atoms is rarely observed in the POM chemistry [14]. The bond lengths and angles in the two compounds are not unusual. All the W centers exhibit octahedral coordination environments and the Ln3+ ions in the two compounds are all in an octacoordinated fashion. The oxidation states of the W, Cu and Ln sites are determined based on the bond lengths and angles, charge balance consideration and bond valence sum calculations, indicating that all W, Cu, Dy and Ho atoms in 1 and 2 are in the +6, +2, +3 and +3 oxidation state, respectively. Bond valence sum calculations also reveal
Fig. 2. Polyhedral and ball‐ and ‐stick representation of the tetrameric aggregate in 1.
that the terminal oxygen atoms associated with the Cu 2+ ions are all diprotonated. The solid-state magnetic behaviors of 1 and 2 were measured in the temperature range of 2.0–300 K at a 0.1 T magnetic field (Figs. 3 and 4), and was plotted as χT versus T. As shown in Fig. 3, χT value slowly decreases from 16.7 cm3 K mol− 1 at room temperature to 16.0 cm3 K mol− 1 at 55 K, and then rapidly drops to a value of 12.1 cm3 K mol− 1 at 2 K. The χ− 1 versus T plot is fitted by the Curie–Weiss law in the whole temperature range with C = 16.83 cm3·K·mol− 1 and Ө = −5.43 K. The χT value of 1 is 16.7 cm 3 K mol − 1 at room temperature, which is a little lower than that of the expected values for nine Cu 2+ (S = 1/2) and one Dy III noninteracting ions: 17.5 cm 3 K mol − 1 for 1 (Dy III: 6 H15/2, S = 5/2, L = 5, g = 4/3, C = 14.17 cm 3 K mol − 1). For compound 2, χT value slowly decreases from 17.5 cm3 K mol− 1 at 300 K to 16.8 cm3 K mol− 1 at 55 K, and then rapidly drops to a value of 9.8 cm3 K mol− 1 at 2 K. The χ− 1 versus T plot is fitted by the Curie– Weiss law in the whole temperature range with C =17.6 cm3·K·mol− 1 and Ө = −6.49 K. The χT value of 2 is 17.6 cm3 K mol− 1 which is a reasonably agreement with the expected values for nine Cu2+ (S = 1/2) and one HoIII noninteracting ions: 17.43 cm3 K mol− 1 (HoIII: S = 2, L = 6, g= 5/4, C= 14.06 cm3·K·mol − 1). The χT value slowly decreases upon lowing the temperature of the two compounds may result from spin-orbit coupling of lanthanide ion. In conclusion, two 1D chain-like structures built upon 3d–4f heterometals-containing silicotungstates have been obtained by the reactions of K8[β2-SiW11O39]·14H2O, Dy 3+, and Cu 2+ with the assistance of organic ligands under hydrothermal conditions. The chainlike structures in 1 and 2 provide novel examples of condensation of discrete clusters through TM and Ln cations into extended structures. Future research will focus on the synthesis of 3D porous framework
Fig. 3. Temperature dependence of (a) χ and (b) χT values and (inset) temperature dependence of reciprocal magnetic susceptibility χ− 1 for 1.
72
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73
Fig. 4. Temperature dependence of (a) χ and (b) χT values and (inset) temperature dependence of reciprocal magnetic susceptibility χ− 1 for 2.
materials based on the Ln-containing sandwich-type polyoxoanions and other TM cations. This work is ongoing in our group. Acknowledgments This work was supported by the National Natural Science Foundation of China (21101022). Appendix A. Supplementary data The experiments in detail, crystal data, IR spectra, TG curves, XRD pattern, additional figures and X-ray crystallographic information file (CIF) are available for compounds 1 and 2. Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.inoche.2012. 06.010. References [1] (a) A. Müller, F. Peters, M.T. Pope, D. Gatteschi, Polyoxometalates: very large clusters nanoscale magnets, Chem. Rev. 98 (1998) 239–271; (b) P. Mialane, A. Dolbecq, F. Sécheresse, Functionalization of polyoxometalates by carboxylato and azido ligands: macromolecular complexes and extended compounds, Chem. Commun. 33 (2006) 3477–3485; (c) C. Pichon, P. Mialane, E. Rivière, G. Blain, A. Dolbecq, J. Marrot, F. Sécheresse, C. Duboc, The highest D Value for a MnII ion: investigation of a manganese(II) polyoxometalate complex by high-field electron paramagnetic resonance, Inorg. Chem. 46 (2007) 7710–7712; (d) D.L. Long, E. Burkholder, L. Cronin, Polyoxometalate clusters, nanostructures and materials: from self assembly to designer materials and devices, Chem. Soc. Rev. 36 (2007) 105–121. [2] (a) J.M.C. Juan, E. Coronado, Magnetic clusters from polyoxometalate complexes, Coord. Chem. Rev. 193–195 (1999) 361–394; (b) J.T. Rhule, C.L. Hill, D.A. Judd, R.F. Schinazi, Polyoxometalates in medicine, Chem. Rev. 98 (1998) 327–357; (c) A. Proust, R. Thouvenot, P. Gouzerhg, Functionalization of polyoxometalates: towards advanced applications in catalysis and materials science, Chem. Commun. 16 (2008) 1837–1852; (d) S.T. Zheng, J. Zhang, G.Y. Yang, Designed synthesis of POM-organic frameworks by Ni6PW9 building blocks under hydrothermal conditions, Angew. Chem. Int. Ed. 47 (2008) 3909–3913; (e) L.X. Shi, X.W. Zhang, C.D. Wu, The synergistic effect of [WZn(VO)2(ZnW9O34)2]12− cores and peripheral metal sites in catalytic oxidative cyclization of acetylacetone, Dalton Trans. 40 (2011) 779–781. [3] (a) C. Ritchie, A. Ferguson, H. Nojiri, H.N. Miras, Y.F. Song, D.L. Long, E. Burkholder, M. Murrie, P. Kögerler, E.K. Brechin, L. Cronin, Polyoxometalate-mediated self-assembly of single-molecule magnets: {[XW9O34]2[MnIII4MnII2O4(H2O)4]}12−, Angew. Chem. Int. Ed. 47 (2008) 5609–5612; (b) A.E. Kuznetsov, Y.V. Geletii, C.L. Hill, K. Morokuma, D.G. Musaev, Dioxygen and water activation processes on multi-Ru-substituted polyoxometalates: comparison with the “Blue-dimer” water oxidation catalyst, J. Am. Chem. Soc. 131 (2009) 6844–6854; (c) M.A. AlDamen, J.M. Clemente-Juan, E. Coronado, C. Martí-Gastaldo, A. Gaita-Ariño, Mononuclear lanthanide single-molecule magnets based on polyoxometalates, J. Am. Chem. Soc. 130 (2008) 8874–8875;
(d) D. Barats, G. Leitus, R. Popovitz-Biro, L.J.W. Shimon, R. Neumann, A stable “End-On” iron(III)–hydroperoxo complex in water derived from a multi-iron(II)-substituted polyoxometalate and molecular oxygen, Angew. Chem. Int. Ed. 47 (2008) 9908–9912; (e) F.P. Xiao, J. Hao, J. Zhang, C.L. Lv, P.C. Yin, L.S. Wang, Y.G. Wei, Polyoxometalatocyclophanes: controlled assembly of polyoxometalate-based chiral metallamacrocycles from achiral building blocks, J. Am. Chem. Soc. 132 (2010) 5956–5957. [4] (a) R. Copping, A.J. Gaunt, I. May, C.A. Sharrad, D. Collison, M. Helliwell, O.D. Foxc, C.J. Jones, Oxoneptunium(V) as part of the framework of a polyoxometalate, Chem. Commun. 36 (2006) 3788–3790; (b) L.H. Bi, U. Kortz, S. Nellutla, A.C. Stowe, J. van Tol, N.S. Dalal, B. Keita, L. Nadjo, Structure, electrochemistry, and magnetism of the iron(III)-substituted Keggin dimer, [Fe6(OH)3(A-α-GeW9O34(OH)3)2]11−, Inorg. Chem. 44 (2005) 896–903; (c) L. Li, Q. Shen, G. Xue, H. Xu, H. Hu, F. Fu, J. Wang, Two sandwich arsenomolybdates 9− based on the new building block As(III)Mo7O27 : [Cr2(AsMo7O27)2]12− and [Cu2(AsMo7O27)2]14−, Dalton Trans. 42 (2008) 5698–5700; (d) Z.M. Zhang, J. Liu, E.B. Wang, C. Qin, Y.G. Li, Y.F. Qi, X.L. Wang, Two extended structures constructed from sandwich-type polyoxometalates functionalized by organic amines, Dalton Trans. 4 (2008) 463–468. [5] (a) S.S. Mal, U. Kortz, The wheel-shaped Cu20 tungstophosphate [Cu20Cl(OH)24 (H2O)12(P8W48O184)]25− ion, Angew. Chem. Int. Ed. 44 (2005) 3777–3780; (b) B. Godin, Y.G. Chen, J. Vaissermann, L. Ruhlmann, M. Verdaguer, P. Gouzerh, Coordination chemistry of the hexavacant tungstophosphate [H2P2W12O48]12− with FeIII ions: towards original structures of increasing size and complexity, Angew. Chem. Int. Ed. 44 (2005) 3072–3075; (c) G.S. Kim, H.D. Zeng, D. VanDerveer, C.L. Hill, A supramolecular tetra-Keggin polyoxometalate [Nb4O6(− Nb3SiW9O40)4]20−, Angew. Chem. Int. Ed. 38 (1999) 3205–3207; (d) C.P. Pradeep, D.L. Long, P. Kögerlerb, L. Cronin, Controlled assembly and solution observation of a 2.6 nm polyoxometalate ‘super’ tetrahedron cluster: [KFe12(OH)18(α-1,2,3-P2W15O56)4]29−, Chem. Commun. 41 (2007) 4254–4256. [6] (a) B.S. Bassil, M.H. Dickman, I. Römer, B.V.D. Kammer, U. Kortz, The tungstogermanate [Ce20Ge10W100O376(OH)4(H2O)30]56−: a polyoxometalate containing 20 cerium(III) atoms, Angew. Chem. Int. Ed. 46 (2007) 6192–6195; (b) F. Hussain, R.W. Gable, M. Speldrich, P. Kögerler, C. Boskovic, Polyoxotungstate-encapsulated Gd6 and Yb10 complexes, Chem. Commun. 3 (2009) 328–330; (c) A. Sartorel, M. Carraro, G. Scorrano, R.D. Zorzi, Polyoxometalate embedding of a tetraruthenium(IV)-oxo-core by template-directed metalation of [γ-SiW10O36]8−: a totally inorganic oxygen-evolving catalyst, J. Am. Chem. Soc. 130 (2008) 5006–5007; (d) K. Fukaya, T. Yamase, Alkali-metal-controlled self-assembly of crown-shaped ring complexes of lanthanide/[α-AsW9O33]9−: [K⊂{Eu(H2O)2(α-AsW9O33)}6]35− and [Cs⊂{Eu(H2O)2(α-AsW9O33)}4]23−, Angew. Chem. Int. Ed. 42 (2003) 654–658. [7] (a) K. Wassermann, M.H. Dickman, M.T. Pope, Self-assembly of supramolecular polyoxometalates: the compact water-soluble heteropolytungstate anion [AsCe(H2O)36W148O524]76−, Angew. Chem. Int. Ed. Engl. 36 (1997) 1445–1448; (b) F. Hussain, F. Conrad, G.R. Patzke, A gadolinium-bridged polytungstoarsenate(III) nanocluster: [Gd8As12W124O432(H2O)22]60−, Angew. Chem. Int. Ed. 48 (2009) 9088–9091. [8] S. Reinoso, Heterometallic 3d–4f polyoxometalates: still an incipient field, Dalton Trans. 40 (2011) 6610–6615. [9] (a) X.K. Fang, P. Kögerler, PO43−-mediated polyoxometalate supercluster assembly, Angew. Chem. Int. Ed. 47 (2008) 8123–8126; (b) X.K. Fang, P. Kögerler, A polyoxometalate-based manganese carboxylate cluster, Chem. Commun. 29 (2008) 3396–3398. [10] (a) B. Nohra, P. Mialane, A. Dolbecq, E. Rivière, J. Marrot, F. Sécheresse, Heterometallic 3d–4f cubane clusters inserted in polyoxometalate matrices, Chem. Commun. 19 (2009) 2703–2705; (b) J.D. Compain, P. Mialane, A. Dolbecq, I.M. Mbomekallé, J. Marrot, F. Séecheresse, C. Duboc, E. Rivière, Structural, magnetic, EPR, and electrochemical characterizations of a spin-frustrated trinuclear CrIII polyoxometalate and study of its reactivity with lanthanum cations, Inorg. Chem. 49 (2010) 2851–2858. [11] (a) S. Reinoso, J.R. Galán-Mascarós, Heterometallic 3d−4f polyoxometalate derived from the weakley-type dimeric structure, Inorg. Chem. 49 (2010) 377–379; (b) A. Merca, A. Müller, J. van Slageren, M. Läge, B. Krebs, Systematic study of the interaction between VIV centres and lanthanide ions MIII in well defined {VIV2MIII}{AsIIIW9O33}2 sandwich type clusters: part 1, J. Clust. Sci. 18 (2007) 711–719; (c) S. Reinoso, J.R.G. Mascarós, L. Lezama, New type of heterometallic 3d–4f rhomblike core in weakley-like polyoxometalates, Inorg. Chem. 19 (2011) 9587–9593. [12] (a) J.F. Cao, S.X. Liu, R.G. Cao, L.H. Xie, Y.H. Ren, C.Y. Gao, L. Xu, Organic–inorganic hybrids assembled by bis(undecatungstophosphate) lanthanates and dinuclear copper(II)–oxalate complexes, Dalton Trans. (2008) 115–120; (b) J.Y. Niu, S.W. Zhang, H.N. Chen, J.W. Zhao, P.T. Ma, J.P. Wang, 1-D, 2-D, and 3-D organic–inorganic hybrids assembled from Keggin-type polyoxometalates and 3d–4f heterometals, Cryst. Growth Des. 11 (2011) 3769–3777; (c) D.Y. Shi, L.J. Chen, J.W. Zhao, Y. Wang, P.T. Ma, J.Y. Niu, Two novel 2D organic– inorganic hybrid lacunary Keggin phosphotungstate 3d–4f heterometallic
S. Yao et al. / Inorganic Chemistry Communications 23 (2012) 70–73 derivatives: [Cu(en)2]2H6[Ce(α-PW11O39)2]·8H2O and [Cu(dap)2(H2O)] [Cu(dap)2]4.5[Dy(α-PW11O39)2]·4H2O, Inorg. Chem. Commun. 14 (2011) 324–329; (d) D.Y. Du, J.S. Qin, S.L. Li, Y.Q. Lan, X.L. Wang, Z.M. Su, 3d–4f Heterometallic complexes for the construction of POM-based inorganic–organic hybrid compounds: from nanoclusters to one-dimensional ladder-like chains, Aust. J. Chem. 63 (2010) 1389–1395. [13] (a) S. Yao, Z.M. Zhang, Y.G. Li, Y. Lu, E.B. Wang, Z.M. Su, Two heterometallic aggregates constructed from the {P2W12}–based trimeric polyoxotungstates and 3d–4f heterometals, Cryst. Growth Des. 10 (2010) 135–139;
73
(b) Z.M. Zhang, Y.G. Li, S. Yao, E.B. Wang, Hexameric polyoxometalates decorated by six 3d–4f heterometallic clusters, Dalton Trans. 40 (2011) 6475–6479; (c) Z.M. Zhang, Y.G. Li, W.L. Chen, E.B. Wang, X.L. Wang, Two-dimensional (3, 6)-topological inorganic aggregate based on the sandwich-type polyoxometalate and lanthanide linkers, Inorg. Chem. Commun. 11 (2008) 879–882. [14] J.-W. Zhao, S.-T. Zheng, Z.-H. Li, G.-Y. Yang, Combination of lacunary polyoxometalates and high-nuclear transition-metal clusters under hydrothermal conditions: first 65·8 CdSO4-type 3-D framework built by hexa-CuII sandwiched polyoxotungstates, Dalton Trans. (2009) 1300–1306.