Novel Three-Dimensional OrganicâInorganic Heterometallic Hybrid

Communication pubs.acs.org/crystal

Novel Three-Dimensional Organic−Inorganic Heterometallic Hybrid Built by Sandwich-Type Tetra-Mn-Substituted Germanotungstates through Mixed 3d and 4f Metal Linkers Hai-Yan Zhao,† Jun-Wei Zhao,*,‡ Bai-Feng Yang,† Huan He,† and Guo-Yu Yang*,†,§ †

DOE Key Laboratory of Cluster Science, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China Henan Key Laboratory of Polyoxometalate Chemistry, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, China § State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China ‡

S Supporting Information *

ABSTRACT: The reaction of trivacant Keegin germanotungstate [A-α-GeW9O34]10− with Mn2+ and Ce4+ cations in the presence of oxalate ligand under hydrothermal conditions led to the isolation of a novel organic−inorganic hybrid 3d−4f heterometallic germanotungstate K4Na4[Ce2(ox)3(H2O)2]2{[Mn(H2O)3]2[Mn4(GeW9O34)2(H2O)2]·14H2O (1) (ox = oxalate), which has been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and single-crystal X-ray crystallography. Interestingly, each tetra-MnIIsubstituted sandwich-type unit acts as 14-dentate ligands to link eight Ce3+ centers and six Mn2+ centers further into a threedimensional (3D) architecture. The 3D structure can be considered as two parts: one is the two-dimensional layer formed by sandwich-type [Mn4(H2O)2(GeW9O34)2]12− fragments and Mn2+ linkers; the other layer is constructed from Ce3+ cations and oxalate bridges, and the two layers are combined together alternately through W−O−Ce−O−W linkers, resulting in the 3D framework. Notably, 1 exhibits the first 3d−4f 3D organic−inorganic hybrid framework constructed by sandwich-type TM-substituted polyoxoanions and mixed 3d and 4f metal linkers in POM chemistry.

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can be exemplified by a rare 3D alumomolybdate [Na4(H2O)14Cu(PDA)2]H[Al(OH)6Mo6O18]·5 H2O (H2PDA= pyrazine2,3-dicarboxylic acid) constructed from Anderson-type [Al(OH)6Mo6O18]3− moieties, tetrameric [Na4(H2O)14]4+ clusters, and [Cu(PDA)2]2− cations.4 (iv) POM-based materials based on various isopolyoxoanion units such as [Ag(CH3CN)3]2[Ag(CH 3 CN) 2 ] 2 [W 10 O 32 ] and [Ag(CH 3 CN) 4 ]⊂{[Ag (CH3CN)2]4[H3W12O40]} as well as a class of 3D inorganic materials based on [H2W12O42]10− building blocks and different alkaline-earth metal linkers (Ca2+, Sr2+, and Ba2+).3c,5 As a continuous exploration of novel-extended POM-based aggregates with the ‘‘property-adding” feature, recently, an effective strategy was concentrated on the introduction of new POM building blocks (beside the commonly used POM precursors) to obtain charming structures and construct multifunctional frameworks of hybrid materials.6 In this aspect, a large subfamily of sandwichtype transition-metal-substituted POTs (TMSPs), as some of the most representative POM species,7 have the larger volume and the more-negative charge than those of the commonly used POMs, which allow the formation of higher coordination numbers with metal cations and should be an ideal class of

he use of polyoxometalates (POMs) as well-known excellent inorganic polydentate building blocks to construct novel-extended materials by means of different cationic linkers is of great interest and a permanent aim that researchers have been pursuing all along, not only from their intriguing variety of architectures and topologies but also from their versatile applications in catalysis, nanoscience, photochemistry, medicine, biochemistry, magnetism, analytical, and materials chemistry.1 In this field, to our knowledge, a large number of extended POMbased materials assembled from the commonly used POM units and different linkers have been extensively reported to date, which can mainly be classified into four types: (i) Keggin-type POM-based materials. For example, Cronin et al. reported a series of extended POM framework solids (C4H10NO)m[W72M12X7O268] that can undergo genuine reversible singlecrystal to single-crystal redox reactions.2 (ii) Dawson-type POMbased materials. For instance, Wang’s group addressed two {P 2 W 12 }-based [K 3 ⊂{GdMn(H 2 O) 10 }{HMnGd 2 (Tart)O 2 (H2O)15}{P6W42O151(H2O)7}]11− (Tart = Tartaric acid anion) and [K3⊂{GdCo(H2O)11}2{P6W41O148(H2O)7}]13−; Cronin’s group discovered a three-dimensional (3D) extended framework based on truncated cuboctahedron [Mn8(H2O)48P8W48O184]24− units and nonclassic Dawson-type antimonio/bismuthotungstates [Ag(CH 3 CN) 3 ]2 [Ag(CH 3 CN) 2 ]2 [H 5Sb/BiW18 O60 ]· 2CH3CN.3 (iii) Anderson-type POM-based materials, which © 2013 American Chemical Society

Received: October 1, 2013 Revised: November 1, 2013 Published: November 8, 2013 5169

dx.doi.org/10.1021/cg4014575 | Cryst. Growth Des. 2013, 13, 5169−5174

Crystal Growth & Design

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hydrothermal conditions; we deliberately attempt to introduce the [A-α-GeW9O34]10− precursor into the {CeIV/MnII/ox2−} system in order to explore a new route for preparing novel high-dimensional organic−inorganic hybrid POM-based frameworks with unexpected structural models and interesting properties. Herein, we present a novel 3D organic−inorganic hybrid 3d−4f heterometallic polyoxotungstate derivative featuring both tetra-MnII-substituted sandwich-type Keggin aggregates and Mn2+ as well as Ce3+ linkers, which is isolated as K4Na4[Ce2(ox)3(H2O)2]2{[Mn(H2O)3]2[Mn4(GeW9O34)2(H2O)2]}·14H2O (1). As far as we know, it is the first 3D organic−inorganic hybrid framework constructed from sandwich-type TM-substituted polyoxoanions and mixed 3d and 4f linkers. Yellow crystals of 1 can be hydrothermally obtained by the reaction of K8Na2[A-α-GeW9O34]·25H2O,18 Ce(NH4)2(NO3)6, and manganese nitrate 50% solution in the presence of oxalic acid dehydrate and aqueous 1 M NaOH in water at 120 °C for 3 days.19 Notably, although the [A-α-GeW9O34]10− polyoxoanion was used as the starting material, the product contains the [B-α-GeW9O34]10− fragments, indicating that the isomerization of [A-α-GeW9O34]10− → [B-α-GeW9O34]10− must have taken place during the course of the reaction. Such isomerization phenomena have already been observed in previous studies.20 Actually, a series of parallel synthetic experiments have been conducted during the course of our exploration: (i) To further explore the effect of the organic ligands on the products, we replaced oxalic acid dehydrate with malonic acid/succinic acid/ citric acid under the same conditions, but unfortunately no isostructural species but amorphous phases were obtained. It can be seen that the size and shape of organic ligands can influence the formation of the resulting products. (ii) We also attempted to investigate the effect of different TM ions on structural diversity by replacing the MnII ion by the FeII, CoII, NiII, CuII, ZnII, CrIII, or FeIII cations. However, after plenty of parallel experiments, we could not obtain the expected compounds but only amorphous precipitates or tetra-TM-substituted GTs,21 suggesting that the nature of TM ions played a key role in the construction of products. (iii) The reaction temperature should be in the range of 110−120 °C, when the reaction temperature is below 110 °C (80−110 °C); tetra-Mn-substituted GTs are easily obtained,21b while when the reaction temperature is above 120 °C (120−170 °C), only amorphous phases are obtained. (iv) When we introduced Na9[A-α-PW9O34]·7H2O, Na10[A-αSiW9O34]·19H2O, or K12[α-H2P2W12O48]·24H2O precursors to the {CeIV/MnII/ox2−} systems, no analogous was harvested but only several tetra-Mn-substituted POTs were isolated.22 (iv) Moreover, similar reactions with other 4f ions (LnIII = Eu, Sm, Tb, and Dy) were also performed, but unexpectedly, we could not obtain the expected isomorphic compounds but only amorphous precipitates, showing that the redox properties of CeIV might be crucial in the formation of 1. It is also noteworthy that there are two obvious color changes during the reaction. At the beginning of the reaction, the yellow aqueous solution immediately changed to brown when the mixed solution of Ce(NH4)2(NO3)6 and 1 M NaOH solution was added. However, the brown color changed back to yellow after heating at 120 °C for 3 days. It is presumed that the redox reactions between Mn2+ and Ce4+ ions at room temperature led to the formation of Mn3+ and Ce3+ ions, which exhibits the brown color. After sealed in a stainless steel reactor with a Teflon liner and heated at 120 °C for 3 days, the disproportionation reaction of the metastable Mn3+ ions occurred, which resulted in the

candidates for constructing the high-dimensional extended materials.8 Following this strategy, we should mention another key factor, that is, the choice of various “cationic linkers” such as transition metal (TM) ions or lanthanide (Ln) cations that can effectively connect sandwich-type TMSP fragments together. To our knowledge, since the first series of extended organic− inorganic hybrid materials built from tetra-TM substituted sandwich-type POTs and TM complexes [Cu(dien)(H2O)]2[Cu(dien)(H 2 O)] 2 [Cu(dien)(H 2 O) 2 ] 2 [Cu 4 (SiW 9 O 34 ) 2 ]}· 5H2O, [Zn(enMe)2(H2O)]2{[Zn(enMe)2]2[Zn4(HenMe)2(PW9O34)2]}·8H2O, and [Zn(enMe)2(H2O)]4[Zn(enMe)2]2{(enMe)2{[Zn(enMe)2]2[Zn4(HSiW9O34)2]}{[Zn(enMe)2(H2O)]2[Zn4(HSiW9O34)2]}}·13H2O (dien = diethylenetriamine) were discovered by Yang et al. in 2007,9 hitherto, a large number of extended sandwich-type TMSPs by means of TM linkers with fascinating properties have been extensively reported.8b,c,10 Compared with TM cations, oxyphilic Ln cations (Ln3+/4+) are popular linkers due to their high coordination numbers as well as their multiple physicochemical properties.11 However, it is comparatively difficult to find appropriate reaction conditions that would enable the acquisition of novel extended aggregates that are based on sandwich-type TMSPs and Ln linkers, which is probably due to the fact that the pH stability ranges for sandwich-type TMSPs in aqueous solutions are different from those of Ln ions, together with the case that the obvious reactive activity between the highly negative polyanions and strongly oxyphilic Ln cations results in immediate precipitates but not crystals.3a,12 To date, only three examples of extended inorganic aggregates based on sandwichtype TMSPs and Ln linkers have been reported, including a chiral ladderlike chain K4Na2[{Ce(H2O)7}2Mn4Si2W18O68(H2O)2]·21.5H2O based on tetra-MnII-substituted sandwichtype polyanions and cerium cations and a 2D inorganic aggregate K3Na3{Nd2(H2O)12Cu4(H2O)2(SiW9O34)2}·21H2O composed of tetra-CuII-sandwiched POM units and neodymium linkers that were isolated by Wang et al. in 2007−2008,13 as well as a 1D double-chain silicotungstate 3d−4f derivative Cs4[(γ-SiW10O36)2(Cr(OH)(H2O))3(La(H2O)7)2]·19H2O assembled by LaIII cations and tri-CrIII-substituted sandwich-type POM units found by Mialane et al. in 2010.14 From the above, it can be concluded that materials based on sandwich-type TMSPs and Ln linkers are one-dimensional (1D) or two-dimensional (2D) inorganic aggregates; however, high-dimensional organic−inorganic hybrid POM-based frameworks assembled by sandwichtype TMSPs and mixed Ln and TM linkers remain unexplored, which not only provides us with an excellent opportunity but also gives us a great impetus to explore this domain. It is well-known that organic spacers as linkers can tune the binding strength and directionality and play a key role in the construction of POM-based hybrid materials with novel structures and improved properties.15 Also, current efforts indicate that introduction of organic N- and O-donor ligands during the preparations can to some extent stabilize Ln cations and reduce the direct combination between lacunary POM units and Ln cations, which is favored to obtain highdimensional organic−inorganic hybrid POM-based frameworks.16 Furthermore, hydrothermal synthesis has proven to be a most effective method for obtaining extended materials, which provides a great chance for exploring 3d−4f heterometallic POMs.17 As a proof-of-concept for this methodology, therefore, the multidentate O-donor ligand (oxalate) is chosen during our preparations of novel-extended aggregates under 5170



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Supporting Information). The MnII−O bond lengths are ranging from 2.096(8) to 2.221(7) Å (Table S1 of the Supporting Information). These bonds are significantly longer than those of the MnIII-containing POMs and in agreement with other MnII-containing POMs.21b,25 Moreover, it is worth mentioning that each sandwich-type polyoxoanion in 1 coordinates to six crystallographically identical Mn2+ cations via six terminal oxygen atoms, and each Mn2+ cation is in turn coordinated to three dimeric polyoxoanions. On the basis of this arrangement, Weakley-type polyoxoanions and {Mn(H2O)3}2+ linkers are well-arranged into a 2D layer (layer A) on the ab plane (Figure 2a). To comprehend the structure better,

transformation of Mn3+ into Mn2+; thus, the brown solution changed back to yellow. In the previous study, such transformations have been observed.13a The profound investigation on this reaction mechanism is in progress. The experimental PXRD pattern of 1 is in good agreement with the simulated PXRD pattern from the single-crystal X-ray diffraction, suggesting the good phase purity for 1 (Figure S1 of the Supporting Information). The differences in intensity between them may be due to the variation in preferred orientation of the powder sample during collection of the experimental PXRD pattern. Bond−valence sum caculations23 indicate that the oxidation states of W, Ce, and Mn elements in 1 are +6, +3, and +2, respectively (Table S1 of the Supporting Information). Single-crystal X-ray diffraction analysis24 reveals that 1 crystallizes in the triclinic space group P1̅ and shows a unique 3D structure constructed by dimeric [Mn4(H2O)2(GeW9O34)2]12− fragments through Mn2+ and Ce3+ linkers. The dimeric Weakleytype fragment [Mn4(H2O)2(GeW9O34)2]12− (Figure 1a) consists

Figure 2. (a) Layer A, polyhedral diagram of the 2D layer of 1 based on Weakley-type polyoxoanions and the {Mn(H2O)3}2+ linkers. (b) Layer B, stick diagram of the 2D lanthanide−organic layer composed of cerium centers and oxalate ligands (color codes: blue, Ce1; green, Ce2). (c) View of linkage between layers A and B in 1 along the c axis. (d) Topological view of 3D framework along the a axis, arranged in the ABAB... mode. The Na+ and K+ cations and solvent water molecules are omitted for clarity (pink nodes, [Mn4(H2O)2(GeW9O34)2]12− clusters and their surrounding six Mn32+ linkers; blue nodes, oxalatebridging Ce1−Ce1 clusters; green nodes, oxalate-bridging Ce2−Ce2 clusters).

Figure 1. (a) The coordination environment of [Mn4(H2O)2(GeW9O34)2]12− polyoxoanion. (b) The rhomblike Mn4O14(H2O)2 group sandwiched by two trivacant [B-α-GeW9O34]10− Keggin fragments in 1. (c−e) The coordination environments of the (c) Ce1III, (d) Mn3II, and (e) Ce2III cations in 1. The atoms with the suffix A are generated by the symmetry operation: A, 1 − x, 2 − y, −z.

of two trivacant Keggin [B-α-GeW9O34]10− moieties, sandwiching a central symmetric rhomblike {Mn4O14(H2O)2} segment (Figure 1b) via exposed 14-bridging O atoms from lacunae of two [B-α-GeW9O34]10− units (two μ4-O from one GeO4 groups and 12 μ2-O from 12 WO6 groups). It is noticeable that each trivacant Keggin [B-α-GeW9O34]10− subunit is bound to three Mn32+, two Ce13+, and two Ce23+ cations, hence, the dimeric tetra-MnII-substituted sandwich-type fragment acts as 14-dentate inorganic ligand coordinating to eight Ce3+ centers and six Mn2+ centers (Figure 1a). Although the sandwich-type TMSP aggregates have abundant oxygen atoms available to coordinate to TM or Ln metals, their connection numbers are no more than that of the [Mn4(H2O)2(GeW9O34)2]12− fragment in 1. So the sandwich-type polyoxoanion fragment in 1 has the highest coordination number to date in the 3d−4f POM chemistry. In addition, three independent Mn2+ cations (Mn1, Mn2, and Mn3) all exhibit the octahedral coordination environments defined by six oxygen atoms, but their coordinated water oxygen atoms are 1, 0, and 3, respectively; other coordinated oxygen atoms are from different trivacant Keggin [B-α-GeW9O34]10− moieties (Figure 1d and Figures S2 (panels a and b) of the

a simplified diagram of the (3,6)-connected 2D layer can be rationalized, if dimeric [Mn4(H2O)2(GeW9O34)2]12− polyoxoanions are taken as six-connected nodes and Mn3(H2O)32+ ions as three-connected nodes (Figure 3a). There are two crystallographically unique Ce3+ cations that exhibit the nine-coordinate distorted tricapped trigonal prismatic geometry. In the coordination configuration of the Ce1III cation, the O29, O36, O2W and the O3, O39, O43 groups constitute the two bottom surfaces of the trigonal prism, while O35, O40, and O44 occupy the three-cap positions covering the side planes defined by the O3−O39−O36−O2W, O29−O36−O39−O43, and O3−O43−O29−O2W groups, respectively (Figure 1c). But in the coordination geometry of the Ce2III cation, the O19, O37, O46 and O31, O41, O3W groups make up the two bottom surfaces of the trigonal prism, while O38, O42, and O45 occupy the three cap positions covering the side planes defined by the O31−O41−O37−O46, O19−O37−O41−O3W, and O19−O46−O31−O3W groups, respectively (Figure 1e). It can be found that two Ce3+ cations 5171



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ions are taken as 8-connected nodes (pink), whereas ox-bridging Ce1−Ce1 clusters and ox-bridging Ce2−Ce2 clusters are reduced to two 6-connected nodes (blue and green), respectively, so the whole framework possesses a (6,8)-connected topology calculated by the TOPOS 4.0 professional software package27 with a Schlafli symbol of (32·412·58·64·72}{32·48·52·63)2. The Fourier transform-infrared (FT-IR) spectrum was recorded as KBr pellets in a range of 4000−400 cm−1 for 1 (Figure S5 of the Supporting Information). The IR spectrum of 1 displays the characteristic vibration pattern derived from the Keggin framework in the region of 700−1000 cm−1. Four characteristic bands attributable to vas(W−Ot), v(Ge−Oa), vas(W−Ob−W), and vas(W−Oc−W) appear at 935, 879, 770, and 709 cm−1. As we all know, the difference [Δν = νas(CO2−) − νs(CO2−)] between the asymmetric νas(CO2−) and symmetric νs(CO2−) stretching vibration of carboxylic groups has been successfully used to derive information regarding bonding modes of carboxylate groups.28 It is found that strong absorption bands at 1690 and 1350 cm−1 can be regarded as the asymmetric and symmetric stretching vibrations of the carboxylate group of the free oxalate ligand.28a,29 For 1, these bands shift to the lower wavenumber and are observed at 1610 and 1317 cm−1, indicating that the oxalate ligands coordinate to two CeIII ions. The Δν value indicates the presence of the bridging coordination mode for the oxalate ligand. Besides that, the vibration bands centered at 3407 cm−1 are indicative of the presence of lattice water or coordinated water molecules. In a word, the results of the IR spectra are in good agreement with the results obtained from X-ray single-crystal structural analysis. X-ray photoelectron spectroscopy (XPS) was also performed to identify the oxidation states of the manganese centers and cerium centers in 1. The Mn2p3/2 and Mn2p1/2 binding energies of 640.9 and 652.0 eV (Figure S6a of the Supporting Information) are consistent with earlier results,30 indicating that all the Mn centers are +2. Two peaks at 882.0 and 902.6 eV (Figure S6b of the Supporting Information) correspond to the Ce3d5/2 and Ce3d3/2 of the CeIII cations.31 In a word, the XPS results of 1 are in good agreement with the results obtained from bond−valence sum calculations and X-ray single-crystal structural analysis and further confirm that the oxidation states of all Ce and Mn atoms in 1 are +3 and +2, respectively. To investigate the thermal stability of 1, the TG analysis was carried out on the crystalline sample under the flowing air atmosphere with a heating rate of 10 °C min−1 from 25 to 1000 °C (Figure 4). Its TG curve displays two continuous weight loss stages in the range of 30−1000 °C. The first weight loss is 7.13% (calcd 7.02%) from 30 to 257 °C, corresponding to the release of 14 lattice water molecules and 12 coordinated water molecules; upon

Figure 3. (a) View of simplified diagram of (3,6)-connected 2D layer based on the Weakley-type polyoxoanions and the {Mn(H2O)3}2+ linkers along the c axis. (b) View of simplified diagram of (3,3)connected 2D Ln-organic layer along the c axis (pink nodes, [Mn4(H2O)2(GeW9O34)2]12− clusters; yellow nodes, Mn3 atoms; blue nodes, Ce1 atoms; green nodes, Ce2 atoms).

are both bound to two terminal O atoms from different sandwich tetra-Mn II -substituted polyoxoanions [Ce−O: 2.437(7)−2.532(7) Å], six O atoms from three oxalate ligands [Ce−O: 2.481(7)−2.625(9) Å] (Figure S2c of the Supporting Information), and one water molecule [Ce−O: 2.607(12)− 2.619(10) Å]. The CeIII−O bonds are in agreement with other CeIII-containing POMs.25,26 In addition, the most interesting feature is that each C2O42− ligand acts as a tetradentate linker bridging two Ce3+ centers (Figure S2d of the Supporting Information) to form a 2D organic−inorganic layer (Figure 2b), in which two types of different circles (I and II) are observed. Interestingly, ox links Ce1 and Ce2, alternately forming a {Ce1−ox−Ce2−ox−Ce1}2 circle (Circle-I) (Figure S3a of the Supporting Information). In a similar way, eight ox ligands in the μ2-mode bridging eight Ce3+ cations result in the formation of a {Ce1−ox−Ce1−ox−Ce2−ox−Ce2−ox−Ce1}2 circle (Circle-II) (Figure S3b of the Supporting Information). Circle-I and Circle-II are fused by side-sharing; on the basis of this connection mode, it is easy to deduce that each Circle-I is surrounded by four circle-II (Figure S3c of the Supporting Information), while each circle-II is surrounded by four circle-I and four circle-II (Figure S3d of the Supporting Information), which leads to a unprecedented 2D Ln−organic layer (layer B) on the ab plane (Figure 2b). When the ox ligand connects with two CeIII cations and is considered a linear linker, a simplified diagram of (3,3)-connected 2D Ln−organic layer is formed (Figure 3b). Furthermore, as is shown in Figure 2c along the c axis, when viewed from one side of layer A, it can be seen that one of trivacant Keggin [B-α-GeW9O34]10− fragment in each dimeric Weakley-type polyoxoanion is bound to two Ce13+ cations and the other is bound to two Ce23+ cations. From the other side of layer A, the linking mode is similar. So each sandwich-type polyoxoanion in 1 coordinates to four crystallographically identical Ce13+ cations and four crystallographically identical Ce23+ cations via eight terminal oxygen atoms, while each cerium cations are bonded to two O atoms from two different sandwich-type polyoxoanions in the opposite positions; hence, depending on such an interesting linking mode, these two kinds of 2D adjacent layers (layer A and layer B) are joined together through W−O−Ce−O−W linkers into a 3D open framework along the b axis (Figure S4 of the Supporting Information). In addition, the layers alternately pack with the mode of −A−B− A−B−. To better understand this intricate 3D framework, further insight into the architecture can be described by a simple node-and-linker reference net (Figure 2d). The tetraMnII-sandwiched aggregate and its surrounding Mn3(H2O)32+

Figure 4. TG curve of 1. 5172



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B.; Shi, S. Y.; Wang, G. W.; Xu, J. Q. Dalton Trans. 2010, 39, 1916− 1919. (2) (a) Thiel, J.; Ritchie, C.; Miras, H. N.; Streb, C.; Mitchell, S. G.; Boyd, T.; Corella Ochoa, M. N.; Rosnes, M. H.; McIver, J.; Long, D. L.; Cronin, L. Angew. Chem., Int. Ed. 2010, 49, 6984−6988. (b) Thiel, J.; Ritchie, C.; Streb, C.; Long, D. L.; Cronin, L. J. Am. Chem. Soc. 2009, 131, 4180−4181. (c) Ritchie, C.; Streb, C.; Thiel, J.; Mitchell, S. G.; Miras, H. N.; Long, D. L.; Boyd, T.; Peacock, R. D.; McGlone, T.; Cronin, L. Angew. Chem., Int. Ed. 2008, 47, 6881−6884. (3) (a) Yao, S.; Zhang, Z. M.; Li, Y. G.; Lu, Y.; Wang, E. B.; Su, Z. M. Cryst. Growth Des. 2009, 10, 135−139. (b) Mitchell, S. G.; Streb, C.; Miras, H. N.; Boyd, T.; Long, D. L.; Cronin, L. Nat Chem. 2010, 2, 308−312. (c) McGlone, T.; Streb, C.; Busquets-Fité, M.; Yan, J.; Gabb, D.; Long, D. L.; Cronin, L. Cryst. Growth Des. 2011, 11, 2471− 2478. (4) (a) An, H. Y.; Liu, X.; Chen, H.; Han, Z. B.; Zhang, H.; Chen, Z. F. CrystEngComm 2011, 13, 5384−5393. (b) Li, S. Z.; Ma, P. T.; Wang, J. P.; Guo, Y. Y.; Niu, H. Z.; Zhao, J. W; Niu, J. Y. CrystEngComm 2010, 12, 1718−1721. (5) (a) Streb, C.; Ritchie, C.; Long, D. L.; Kögerler, P.; Cronin, L. Angew. Chem., Int. Ed. 2007, 46, 7579−7582. (b) Cui, K. Y.; Li, F. Y.; Xu, L.; Wang, Y. C.; Sun, Z. X.; Fu, H. G. CrystEngComm 2013, 15, 4721−4729. (6) Li, Y. W.; Li, Y. G.; Wang, Y. H.; Feng, X. J.; Lu, Y.; Wang, E. B. Inorg. Chem. 2009, 48, 6452−6458. (7) Evans, H. T.; Tourne, C. M.; Tourne, G. F.; Weakley, T. J. R. J. Chem. Soc., Dalton Trans. 1986, 2699−2705. (8) (a) Zhao, J. W.; Shi, D. Y.; Chen, L. J.; Cai, X. M.; Wang, Z. Q.; Ma, P. T.; Wang, J. P.; Niu, J. Y. CrystEngComm 2012, 14, 2797−2806. (b) Zhao, J. W.; Zhang, J.; Zheng, S. T.; Yang, G. Y. Chem. Commun. 2008, 570−572. (c) Zhao, J. W.; Wang, C. M.; Zhang, J.; Zheng, S. T.; Yang, G. Y. Chem.Eur. J. 2008, 14, 9223−9239. (d) Zhu, G.; Geletii, Y. V.; Song, J.; Zhao, C.; Glass, E. N.; Bacsa, J.; Hill, C. L. Inorg. Chem. 2012, 52, 1018−1024. (9) Zheng, S. T.; Wang, M. H.; Yang, G. Y. Chem.−Asian J. 2007, 2, 1380−1387. (10) (a) Zheng, S. T.; Yang, G. Y. Chem. Soc. Rev. 2012, 41, 7623− 7646. (b) Oms, O.; Dolbecq, A.; Mialane, P. Chem. Soc. Rev. 2012, 41, 7497−7536. (c) Zhao, J. W.; Li, B.; Zheng, S. T.; Yang, G. Y. Cryst. Growth Des. 2007, 7, 2658−2664. (11) (a) Cardona-Serra, S.; Clemente-Juan, J. M.; Coronado, E.; Gaita-Ariño, A.; Camón, A.; Evangelisti, M.; Luis, F.; Martínez-Pérez, M. J.; Sesé, J. J. Am. Chem. Soc. 2012, 134, 14982−14900. (b) Zhang, S. W.; Zhang, D. D.; Ma, P. T.; Liang, Y. F.; Wang, J. P.; Niu, J. Y. CrystEngComm 2013, 15, 2992−2998. (c) Suzuki, K.; Sato, R.; Mizuno, N. Chem. Sci. 2013, 4, 596−600. (12) Zhang, Z. M.; Li, Y. G.; Yao, S.; Wang, E. B. Dalton Trans. 2011, 40, 6475−6479. (13) (a) Chen, W. L.; Li, Y. G.; Wang, Y. H.; Wang, E. B. Eur. J. Inorg. Chem. 2007, 2007, 2216−2220. (b) Zhang, Z. M.; Li, Y. G.; Chen, W. L.; Wang, E. B.; Wang, X. L. Inorg. Chem. Commun. 2008, 11, 879−882. (14) Compain, J. D.; Mialane, P.; Dolbecq, A.; Mbomekallé, I. M.; Marrot, J.; Sécheresse, F.; Duboc, C.; Rivière, E. Inorg. Chem. 2010, 49, 2851−2858. (15) Sha, J. Q.; Sun, J. W.; Li, M. T.; Wang, C.; Li, G. M.; Yan, P. F.; Sun, L. J. Dalton Trans. 2013, 42, 1667−1677. (16) (a) Zhang, S. W.; Wang, Y.; Zhao, J. W.; Ma, P. T.; Wang, J. P; Niu, J. Y. Dalton Trans. 2012, 41, 3764−3772. (b) Li, F. Y.; Guo, W. H.; Xu, L.; Ma, L. F.; Wang, Y. C. Dalton Trans. 2012, 41, 9220−9226. (17) (a) Zhao, J. W.; Shi, D. Y.; Chen, L. J.; Li, Y. Z.; Ma, P. T.; Wang, J. P.; Niu, J. Y. Dalton Trans. 2012, 41, 10740−10751. (b) Shi, D. Y.; Zhao, J. W.; Chen, L. J.; Ma, P. T.; Wang, J. P.; Niu, J. Y. CrystEngComm 2012, 14, 3108−3119. (18) Bi, L. H.; Kortz, U.; Nellutla, S.; Stowe, A. C.; van Tol, J.; Dalal, N. S.; Keita, B.; Nadjo, L. Inorg. Chem. 2005, 44, 896−903. (19) 1 can be prepared as follows: K8Na2[A-α-GeW9O34]·25H2O (0.304 g) and manganese nitrate 50% solution (0.25 mL) were suspended in distilled water (8 mL), and then Ce(NH4)2(NO3)6

further heating, the second weight loss of 7.48% between 257 and 1000 °C is assigned to the removal of six oxalate ligands (calcd 7.91%). The observed experimental values are in approximate consistency with the theoretical values. In conclusion, a unique organic−inorganic hybrid 3d−4f heterometallic germanotungstate 1 has been hydrothermally synthesized for the first time. As far as we know, 1 exemplifies a new type of organic−inorganic hybrid TM−Ln heterometallic POMs. Each tetra-MnII-sandwiched POM unit acts as 14-dentate inorganic ligands to link eight Ce3+ centers and six Mn2+ centers into a 3D extended architecture, which can be considered as two parts: one is the 2D layer constructed from Weakley-type polyoxoanions and Mn2+ linkers, and the other is formed by Ce3+ cations and oxalate bridges. Both are fused together alternately through W−O−Ce−O−W linkers. 1 represents the first 3D organic−inorganic hybrid 3d−4f heterometallic polyoxotungstate derivative composed of sandwich-type TM-substituted polyoxoanion and mixed 3d and 4f linkers. The detailed study of the synthetic conditions reveals that not only hydrothermal technique is an effective synthetic method in the POM field but also the utilization of the organic ligands is an effective method to synthesize more novel 3d−4f heterometallic POMs, which endows us with great opportunities in exploiting and making more novel extended organic−inorganic hybrid Ln−TM heterometallic POM derivatives by means of the appropriate choice of changeable TM ions, Ln cations, different lacunary POM precursors, and various organic ligands. This continuous research is currently going on in our group.

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ASSOCIATED CONTENT

S Supporting Information *

Experimental details, IR and PXRD data, XPS, X-ray crystallographic information file (CIF) CCDC-942424, additional figures and tables. This material is available free of charge via the Internet at http://pubs.acs.org.

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]; [email protected]. Tel/Fax: (+86) 591-8371-0051. *E-mail: [email protected]. Author Contributions

The manuscript was written through the contributions of all authors. All authors have given approval to the final version of the manuscript. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the NNSF of China (Grants 91122028, 21221001, 50872133, and 21101055), the NNSF for Distinguished Young Scholars of China (Grant 20725101), and the 973 program (Grants 2014CB932101 and 2011CB932504).

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REFERENCES

(1) (a) Clemente-Juan, J. M.; Coronado, E.; Gaita-Arino, A. Chem. Soc. Rev. 2012, 41, 7464−7478. (b) Long, D.-L.; Tsunashima, R.; Cronin, L. Angew. Chem., Int. Ed. 2010, 49, 1736−1758. (c) Dolbecq, A.; Dumas, E.; Mayer, C. d. R.; Mialane, P. Chem. Rev. 2010, 110, 6009−6048. (d) Kortz, U.; Müller, A.; van Slageren, J.; Schnack, J.; Dalal, N. S.; Dressel, M. Coord. Chem. Rev. 2009, 253, 2315−2327. (e) Ni, L.; Patscheider, J.; Baldridge, K. K.; Patzke, G. R. Chem.Eur. J. 2012, 18, 13293−13298. (f) Wang, Y.; Ye, L.; Wang, T. G.; Cui, X. 5173



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(0.101 g) was added under stirring. Then aqueous 1 M NaOH (0.25 mL) was added dropwise to the solution with continuous stirring for 20 min. Finally, oxalic acid dehydrate (0.131 g) and 1 M NaOH solution (2 mL) were successively added (the starting pH was 5.2). The resulting brown mixture was sealed in a 35 mL stainless steel reactor with a Teflon liner and heated at 120 °C for 3 days and then cooled to room temperature (the end pH 6.1). Yellow block crystals of 1 were obtained. Yields: 15% based on Ce(NH4)2(NO3)6. Elemental analysis calcd (%) for C6H26Ce2GeK2Mn3Na2O59W9: C, 2.16; H, 0.78. Found: C, 2.05; H, 0.97. IR (KBr, cm−1): 3407(m), 3215(w), 2965 (w), 2923(w), 2853(w), 1610(s), 1403(m), 1386(w), 1317(s), 935(s), 879(s), 770(s), 709(s), 509(m), 470(m). (20) (a) Huang, L.; Zhang, J.; Cheng, L.; Yang, G. Y. Chem. Commun. 2012, 48, 9658−9660. (b) Zheng, S. T.; Zhang, J.; Yang, G. Y. Angew. Chem., Int. Ed. 2008, 47, 3909−3913. (21) (a) Wang, J. P.; Ma, P. T.; Shen, Y.; Niu, J. Y. Cryst. Growth Des. 2008, 8, 3130−3133. (b) Kortz, U.; Nellutla, S.; Stowe, A. C.; Dalal, N. S.; Rauwald, U.; Danquah, W.; Ravot, D. Inorg. Chem. 2004, 43, 2308− 2317. (22) (a) Kortz, U.; Isber, S.; Dickman, M. H.; Ravot, D. Inorg. Chem. 2000, 39, 2915−2922. (b) Gomez-Garcia, C. J.; Coronado, E.; GomezRomero, P.; Casan-Pastor, N. Inorg. Chem. 1993, 32, 3378−3381. (23) Brown, I. D.; Altermatt, D. Acta Crystallogr., Sect. B 1985, 41, 244−247. (24) Crystal data for 1: C6H26Ce2GeK2Mn3Na2O59W9, Mr = 3338.75, triclinic, P1̅, a = 13.1828(4) Å, b = 15.9386(6) Å, c = 16.0139(5) Å, α = 115.179(3)°, β = 105.020(3) °, γ = 102.893(3)°, V = 2718.68(16) Å3, Z = 2, ρcalcd = 4.079 g cm−3, μ = 22.097 mm−1, F(000) = 2966, GOOF = 1.047. A total of 25185 reflections were collected, 11259 of which were unique (Rint = 0.0401). R1/wR2 = 0.0388/0.0835 for 757 parameters and 11259 reflections [I > 2σ(I)]. CCDC-942424 contains the supplementary crystallographic data for this paper. Intensity data were collected on a Gemini A Ultra diffractometer with graphitemonochromated Mo Kα (λ = 0.71073 Å) at room temperature. The program SADABS was used for the absorption correction. The structure was solved by the direct method and refined on F2 by fullmatrix least-squares methods using the SHELX-97 program package. All nonhydrogen atoms were refined anisotropically except for some oxygen atoms. (25) Reinoso, S.; Galán-Mascarós, J. R. Inorg. Chem. 2009, 49, 377− 379. (26) Bassil, B. S.; Dickman, M. H.; Römer, I.; von der Kammer, B.; Kortz, U. Angew. Chem., Int. Ed. 2007, 46, 6192−6195. (27) Blatov, V. A.; Shevchenko, A. P. TOPOS, v.4.0 Professional (beta evaluation), Samara State University: Samara, Russia, 2006. (28) (a) Zhang, S. W.; Zhao, J. W.; Ma, P. T.; Niu, J. Y.; Wang, J. P. Chem.−Asian J. 2012, 7, 966−974. (b) An, H. Y; Zhang, H.; Chen, Z. F.; Li, Y. G.; Liu, X.; Chen, H. Dalton Trans. 2012, 41, 8390−8400. (29) (a) Zhao, H. Y.; Zhao, J. W.; Yang, B. F.; He, H.; Yang, G. Y. CrystEngComm 2013, 15, 5209−5213. (b) Zhang, D. D.; Zhang, S. W.; Ma, P. T.; Wang, J. P.; Niu, J. Y. Inorg. Chem. Commun. 2012, 20, 191− 195. (30) (a) Lebrini, M.; Mbomekallé, I. M.; Dolbecq, A.; Marrot, J.; Berthet, P.; Ntienoue, J.; Sécheresse, F.; Vigneron, J.; Etcheberry, A. Inorg. Chem. 2011, 50, 6437−6448. (b) Han, Y. F.; Chen, F. X.; Zhong, Z. Y.; Ramesh, K.; Chen, L. W.; Widjaja, E. J. Phys. Chem. B 2006, 110, 24450−24456. (31) (a) Chen, W. C.; Li, H. L.; Wang, X. L.; Shao, K. Z.; Su, Z. M.; Wang, E. B. Chem.Eur. J. 2013, 19, 11007−11015. (b) Ding, J. Q.; Weng, L. T.; Yang, S. H. J. Phys. Chem. B 1996, 100, 11120−11121.

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