- Email: [email protected]
Synthesis and characterization of two new organically templated indium phosphites built from one-dimensional ladders
Microporous and Mesoporous Materials 96 (2006) 287–292 www.elsevier.com/locate/micromeso
Synthesis and characterization of two new organically templated indium phosphites built from one-dimensional ladders Li Wang, Tianyou Song, Jianing Xu, Ying Wang, Zhenfen Tian, Suhua Shi
*
Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Department of Chemistry, Jilin University, Changchun 130012, China Received 9 April 2006; received in revised form 4 July 2006; accepted 10 July 2006 Available online 23 August 2006
Abstract Two new indium phosphites, (C2N2H10)[In(OH)3(HPO3)] I and (C4N2H12)[In2(HPO3)3(H2PO3)2] II have been synthesized under mild hydrothermal conditions using ethylenediamine and piperazine as structure-directing agents, respectively and characterized by singlecrystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, TGA, ICP-AES and elemental analyses. Compound I displays a one-dimensional ladder structure containing edge-sharing four-member rings. Compound II displays a complex three-dimensional open-framework containing multi-dimensional intersecting eight-membered ring channels. It is noted that compound II is the first organically templated indium phosphite with three-dimensional open-framework. Another striking feature of II is that it possesses a novel twodimensional double sheet which is constructed by H2PO3 pseudo-pyramids and the one-dimensional ladders that are similar to those ˚ , b = 9.7106(9) A ˚, observed in I. Crystal data: I, H14C2N2O6PIn, M = 307.94, orthorhombic, space group P212121, a = 6.6483(6) A ˚ , V = 836.28(13) A ˚ 3, Z = 4, and II, H19C4N2O15P5In2, M = 719.70, monoclinic, space group P21/c, a = 9.4610(2) A ˚, c = 12.9537(12) A ˚ , c = 20.963(5) A ˚ , b = 100.186(1), V = 1835.6(7) A ˚ 3, Z = 4. b = 9.4028(2) A 2006 Elsevier Inc. All rights reserved. Keywords: Open-framework; Crystal structure; Hydrothermal synthesis; Indium phosphite; Organic template
1. Introduction In the past decades, metal phosphates with open architectures have been synthesized due to their rich structural chemistry and the potential applications in ion exchange, separation and catalysis [1]. These compounds occur as zero- (clusters), one- (chains or ladders), two- (layers), and three-dimensional structures. One of the strategies used for the design and synthesis of new materials in this system is the employment of organic amines as structuredirecting agents. The transfer of a variety of organic amines to inorganic products allows the formation of otherwise unattainable inorganic structures [1] and the transformation of zero- or one-dimensional structures to two-dimensional layers as well as three-dimensional structures with channels [2]. More recently, the pseudo-pyramidal phos*
Corresponding author. Tel.: +86 431 5168471; fax: +86 431 5671974. E-mail address: [email protected] (S. Shi).
1387-1811/$ - see front matter 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.micromeso.2006.07.008
phite [HPO3] group has been investigated as a possible replacement for the traditional phosphate tetrahedron with great success [3]. Compared to phosphate ½PO3 4 , the pyramidal hydrogen phosphite group ½HPO2 only 3 links three adjacent cations via P–O–M (M = metal) bonds, which might be expected to lead to a new class of compounds with interesting architectures. Since the vanadium phosphites with piperazinium cations as structurally directing agents [H2NC4H8NH2][(VO)3(HPO3)4(H2O)2] were synthesized by Zubieta et al. [4], a number of studies on the metal phosphites containing Zn, Co, Fe, V, Mn, and Cr have been carried out [3]. However, less exploratory work has been carried out on synthesizing the organically templated main group metal phosphates [5–7]. With an aim toward searching for novel organically templated phosphites, we conducted our study on the hydrothermal synthesis in indium–phosphite–amine systems. In our experiments, InCl3, H3PO3 and ethylenediamine (en) were selected as starting materials to prepare an indium
288
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
phosphite (C2N2H10)[In(OH)3(HPO3)] I, which has a onedimensional ladder structure. Our efforts were then focused on the replacement of ethylenediamine by other organic amines in order to make compound I with the one-dimensional ladder structure transform to two-dimensional layers or three-dimensional structures with channels. Finally, in the presence of piperazine a new three-dimensional indium phosphite (C4N2H12)[In2(HPO3)3(H2PO3)2] II with the multi-dimensional intersecting eight-membered ring channels was synthesized under hydrothermal conditions, which is constructed from the HPO3 pseudo-pyramids and onedimensional ladders that are similar to those observed in compound I. Herein we describe the synthesis, crystal structure and characterization of I and II, along with the effect of organic amine on formation of I and II. 2. Experimental 2.1. Materials and instrumentation All chemicals were obtained from commercial sources and used without further purification. The elemental analysis was conducted on a Perkin Elmer 2400 elemental analyzer. ICP-AES (inductively coupled plasma-atomic emission spectroscope) analysis was performed on a Perkin Elmer Optima 3300DV ICP instrument. Powder X-ray diffraction (XRD) data were obtained using SHIMADAZU XRD-6000 diffractometer with Cu-Ka radiation ˚ ), with the step size and the count time of (k = 1.5418 A 0.02 and 4 s, respectively. FT-IR spectra were recorded on a Nicolet Impact 410 spectrometer between 400 and 4000 cm1 using the KBr pellet method. Thermogravimetric analysis (TGA) was conducted on a SHIMADAZU DTG 60 thermogravimetric analyzer with a heating rate of 10 C min1 under nitrogen gas. 2.2. Synthesis Compound I was prepared from a reaction mixture of InCl3 Æ 4H2O, H3PO3, en and water with a molar ratio of 0.5:2.4:3.0:277. A typical synthesis procedure begins with mixing 0.16 g InCl3, 0.20 g H3PO3, 0.20 ml en, and 5 ml of water to form a reaction mixture. The mixture was stirred for 30 min at room temperature, then the mixture was transferred to a 23 ml PTFE-lined stainless-steel hydrothermal autoclave at a filling capacity of 22% and heated at 180 C for 7 d under autogenous pressure. Fine rod-shaped crystals, were filtered off, washed with water and dried at room temperature (yield = 60% based on In). Elemental analysis data were satisfactory (C obsd. (%), calcd. (%), 7.81, 7.79; H, 4.60, 4.55; N, 9.07, 9.09). The XRD pattern of I is consistent with the simulated one on the basis of single-crystal structure, indicating the phase purity of the as-synthesized sample (Fig. 1a). The compound II was prepared from a reaction mixture of InCl3 Æ 4H2O, H3PO3, piperazine and water with a molar ratio of 0.5:17.1:4.0:666. A typical synthesis procedure
Fig. 1. Simulated and experimental power X-ray diffraction patterns of compound I (a) and II (b).
begins with mixing 0.16 g InCl3, 1.40 g H3PO3, 0.80 g piperazine hexahydrate, and 12 ml of water to form a reaction mixture. The reaction mixture was stirred for 1 h at room temperature, then the mixture was transferred to a 23 ml PTFE-lined stainless-steel hydrothermal autoclave at a filling capacity of 52% and heated at 180 C for 7 d under autogenous pressure. The product containing block crystals was collected by filtration, washed thoroughly with distilled water, and dried in air at room temperature (51% yield based on In). The agreement between the experimental and simulated XRD patterns indicated the phase purity of the product (Fig. 1b). The difference in reflection intensities between the simulated and experimental patterns was due to the variation in preferred orientation for the powder sample. The ICP and elemental analysis results were also consistent with the theoretical values: C obsd. (%), calcd. (%), 6.70, 6.67; H, 2.72, 2.63; N, 3.90, 3.89; In, 31.89, 31.92; P, 21.58, 21.54. 2.3. Crystal structure determination Suitable single crystals with dimensions of 0.30 · 0.18 · 0.13 mm3 for I and 0.20 · 0.18 · 0.16 mm3 for II were carefully selected for single-crystal X-ray diffraction analysis.
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
289
Table 1 Crystallographic data for compounds I and II C4H19In2N2O15P5 Empirical formula H14C2N2O6PIn Formula weight 307.94 719.70 Crystal system Orthorhombic Monoclinic Space group P212121 P21/c ˚) a (A 6.6483(6) 9.461(2) ˚) b (A 9.7106(9) 9.4028(2) ˚) c (A 12.9537(12) 20.963(5) ˚) b (A 100.186(1) ˚ 3) ˚3 V (A 836.28(13) A 1835.6(7) Z 4 4 Dc (g cm3) 2.446 2.604 l (mm1) 3.016 3.028 Reflections 5052/1846 12,673/4515 collected/unique [Rint = 0.0517] [Rint = 0.1522] Data/restraints/ 1846/0/113 4515/3/270 parameters Goodness-of-fit 1.070 1.002 on F2 Final R indices R1 = 0.0329, R1 = 0.0377, [I > 2r(I)] wR2 = 0.0843 wR2 = 0.0702 Largest diff. 1.689 and 0.598 1.222 and 1.735 ˚ 3] peak/hole [e A P P P P R1 ¼ jjF o j jF cs jj= jF o j, wR2 ¼ ½wðF 2o F 2c Þ2 = ½wðF 2o Þ2 1=2 .
The intensity data were collected on a Siemens Smart CCD diffractometer equipped with graphite-monochromated ˚ ) radiation in the x scanning mode Mo-Ka (k = 0.71073 A at room temperature. No significant decay was observed during the data collection. Empirical absorption correction was applied using the SADABS program [8]. Data were processed on a Pentium PC using Bruker AXS Windows NT SHELXTL software package (version 5.10) [9,10]. The structure was solved by direct method and refined with full-matrix least squares. All the non-hydrogen atoms were refined anisotropically. Hydrogen atoms were placed geometrically and located in the difference Fourier map. Experimental details for the structural determinations of I and II are summarized in Table 1. CCDC-250379 and CCDC-600044 contain the supplementary crystallographic data for compound I and II, respectively. These data can be obtained free of charge at www.ccdc.cam.ac.uk [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (internat.) +44-1223/336-033; e-mail: [email protected]].
Fig. 2. Asymmetric unit of compound I with detailed labeling of the atoms.
nation geometry with average P–O bond length of ˚ and the terminal P–H bond length is 1.34(4) A ˚ 1.513(4) A which is similar to the P–H bond length reported in H3PO3 previously [4]. The existence of P–H bond is also verified by the IR spectrum, which exhibits strong absorption at 2397 cm1 [3]. There is one diprotonated ethylenediamine molecule in the asymmetric unit. The crystal structure of the title compound consists of [In(OH)3(HPO3)]2 infinite edge-sharing four-member ring ladders propagating along the a axis. The en cations are in the cavities of the structure delimited by three different chains, and both ionic interactions with the anionic chains exist (shown in Fig. 3a). The structure of the [In(OH)3(HPO3)]2 anionic chains is constructed from isolated InO3(OH)3 octahedra and pseudo-pyramidal (HPO3)2 phosphite oxoanions. The InO3(OH)3 octahedron shares the trans O1 and O4 atoms with the HPO3 pseudo-pyramid, forming an infinite chain of alternating octahedra and pseudo-pyramids. Each octahedron also shares its O5 atom with another HPO3 pseudo-pyramid belonging to a parallel chain, giving rise to the infinite ladder-like chains as shown in Fig. 3b.
3. Results and discussion 3.1. Structural description Crystal structure of (C2N2H10)[In(OH)3(HPO3)], I: The asymmetric unit of I contains 14 non-hydrogen atoms (1In, 1P, 8O, 2N and 2C) as shown in Fig. 2. The In atom adopts six coordination geometry with six oxygen atoms occupying each coordination site. The In–O bond lengths ˚ (av. 2.093(6) A ˚) are in the range of 2.042(3)–2.120(3) A and O–In–O angles are in the range of 85.06(11)– 173.33(12). The P atom adopts pseudo-pyramidal coordi-
Fig. 3. Polyhedral view of the structure of compound I along the [1 0 0] direction (a) and the one-dimensional ladder containing edge-sharing fourmembered rings along a axis (b).
290
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
Fig. 4. Asymmetric unit of compound II with detailed labeling of the atoms.
Crystal structure of (C4N2H12)[In2(HPO3)3(H2PO3)2], II: The asymmetric unit of II contains 28 non-hydrogen atoms, of which 22 belong to the framework and six belong to the guest species as shown in Fig. 4. There are two crystallographically independent indium and five phosphorus atoms. All In atoms are linked to the P atoms via oxygen bridges. The In–O bond lengths are in the range of ˚ and O–In–O angles are in the range 2.103(3)–2.165(3) A of 79.87(14)–176.99(12). All P atoms adopt pseudo-pyramidal coordination geometry, each bonded to three oxygen atoms and one hydrogen atom. All oxygen atoms bridge to the In atoms with the exception of two, which we have identified as terminal OH groups. The terminal P–H bond ˚ which are lengths are in the range of 1.32(4)–1.43(2) A similar to the P–H bond length reported in metal phosphite previously [11]. The existence of P–H bond is also verified by the IR spectrum, which exhibits strong absorption at 2415 cm1 [3]. The framework stoichiometry of [In2(HPO3)3(H2PO3)2] creates a net charge of 2, which is balanced by one diprotonated piperazine cation. The crystal structure of II may be viewed as the stacking of the [In2(HPO3)2(H2PO3)2] layers with HPO3 pseudo-pyramids as pillars to form the three-dimensional open-framework with multi-dimensional intersecting eight-membered
ring channels. As shown in Fig. 5b, the [In2(HPO3)2(H2PO3)2] layer is constructed by the HPO3 pseudo-pyramids and one-dimensional ladders which are built up from alternating two different types of four-membered rings. Though the four-membered rings both are composed of two InO6 octahedra and two HPO3 pseudo-pyramids, fused via In–O–P vertices, one of them is built from two In(1) atoms and two P(1) atoms, the other one from two In(2) atoms and two P(4) atoms. They alternately connect each other through O(4) and O(11) atoms to form the infinite ladders along the a axis (shown in Fig. 5a) which are similar to those found in compound I. These ladders are connected together in [0 0 1] plane in a very unusual and hitherto unreported way. As shown in Fig. 5b, the adjacent ladders stack paralleling the [1 0 0] direction and further interconnect via H2P(2)O3 and H2P(5)O3 pseudo-pyramids to generate 2D double sheets with interleaving eight-membered ring openings toward the [0 0 1] direction. A series of inorganic layers are held together in –ABAB– stacking sequence along the [0 0 1] direction. These are further linked by HP(3)O3 pseudo-pyramids which coordinate to In(1)O6 and In(2)O6 octahedra from four-membered rings on each of two adjacent layers, forming a three-dimensional openframework with intersecting eight-membered ring channels along the [1 0 0] and [0 1 0] directions, respectively (shown in Fig. 6). The diprotonated piperazine cations are located in the eight-membered ring channels and neutralize the negative charge of the inorganic framework. It is noted that the compound II is the first three-dimensional open-framework organically templated indium phosphite. 3.2. Discussion Compounds I and II are synthesized under hydrothermal conditions. It can be shown that the formation of compounds I and II is greatly influenced by the indium source and solvent. Using In2O3 as indium source, neither compound I nor compound II was obtained in similar experimental conditions. If the solvent was replaced by
Fig. 5. (Left) Polyhedral view of the one-dimensional ladder of compound II along a axis (a) and two-dimensional layer with interleaving eight-membered ring openings along [0 0 1] direction built from the one-dimensional ladders and H2PO3 pseudo-pyramids (b); (right) schematic drawing of one-dimensional ladder along a axis (a) and two-dimensional layer along [0 0 1] direction (b) of compound II.
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
291
Fig. 6. Polyhedral view of the structure of compound II with intersecting eight-membered ring channels along [1 0 0] and [0 1 0] directions, respectively.
1-butanol or glycol, the amorphous phase or thick gel were produced. The amount of water is the other factor that effects the crystallization of II. Using InCl3 Æ 4H2O as indium source, microcrystals of II were synthesized in the mixture with molar ratios of 0.5InCl3 Æ 4H2O: 17.1H3PO3:4.0piperazine:556H2O. When increasing the molar amount of water to 666 and keeping other conditions unchanged, block crystals of II were obtained, when decreasing the molar amount of water to less than 444, no crystals of II were prepared except for a thick gel. The IR spectra of compounds I and II show the bands corresponding to the vibrations of the organic amine cations and phosphite ions. The vibrational modes and their frequencies are given in Table 2. These results are similar to those found in other related compounds [3–7]. Thermogravimetric analyses of compounds I and II were carried out under nitrogen gas with a heating rate of 10 C min1. TGA for I shows two continual stages of weight loss with a total of 40.75% around 280–590 C, which is attribute to the decomposition of diprotonated en cations (calcd. 20.78% for one en cation per formula unit), the dehydration (calcd. 11.69% for two water molecules per formula unit) and a partial release (8.28%) of volatile phosphorus oxide [12] (approximately 17.86% of ‘‘P2O3’’ molecules per formula unit). XRD analysis shows the residue is amorphous. Thermogravimetric analysis shows a two-step weight Table 2 Selected bands (cm1) from the IR spectra for compounds I and II Assignment
I
II
m(NH3)+ m(–CH2–) m(HP) d(–NH3)+ d(–CH2–)
3152, 3057 (m) 2928 (m) 2402 (m) 1612 (m) 1516 (m), 1458 (w)
mas(PO3) ms(PO3) d(HP) ds(PO3) das(PO3)
1079 (s) 1015 (s) 920 (m) 598 (m) 495 (m)
3429, 3031 (m) 2819, 2794 (m) 2446, 2408 (m) 1605 (m) 1465 (m), 1336 (w) 1156, 1092 (s) 1028, 983 (s) 951 (m) 604, 580 (m) 476 (m)
m: stretching; d: deformation; s: symmetric; as: asymmetric; w: weak; m: medium; s: strong.
loss process for compound II. The first step occurring between 300 and 820 C is due to the decomposition of piperazinium cations. However, the observed mass loss (7.39%) is much lower than the expected value (12.22%). The lower reduction in mass loss is likely due to the retention of piperazine cations in the solid residue. The second event starting at 835 C with a mass loss of 51.52% is assigned to the removal of the residual piperazine species (4.83%) and the dehydration (calcd. 8.75% for 3.5 water molecules per formula unit) and a partial release (37.94%) of volatile phosphorus oxide (approximately 38.21% for the 2.5 mol of ‘‘P2O3’’ molecules per formula unit), respectively. The residue is amorphous and its phase is unidentified. The organic amine molecule plays a central role for the production of the open-framework materials. Two parameters relative to the nature of the amine are important: the size and shape of the amine (either spherical or linear) and its correlated ability to be protonated. Hence, the volume, the anisotropy of shape, and the charge will influence the structure and the porosity of the solid. Using several amines of varying chain lengths as templates, a series of open-framework gallium phosphates (designated ULM-n) were synthesized and it showed that the pore size increases with the carbon number [13–15]. Rao reported the transformation of low-dimensional zinc phosphates to complex open-framework structures by changing organic amine molecules [2,16]. Herein, using en as structure-directing agent, a one-dimensional ladder structure indium phosphite I was first synthesized, then with piperazine replacement of en, a new three-dimensional open-framework structure indium phosphite II was prepared under appropriate conditions. Due to the structure-directing effect of piperazine, the 1D four-membered ring ladders that are similar to those observed in I are held together with H2PO3 pseudo-pyramids to form the 2D double sheets. These layers are further pillared by HPO3 pseudo-pyramids forming a 3D openframework with intersecting eight-membered ring channels along the [1 0 0] and [0 1 0] directions, respectively. A large number of the edge-sharing four-member ring chains [17,18] which are constructed by alternating tetrahedra are reported in the literature, however, the ladders that are observed in compounds I and II constructed by
292
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
alternating octahedra and pseudo-pyramids are very rare. The differences between them may derive from the different building unit and metal/phosphorous ratio. The structures of the compounds containing four-membered ring ladders are usual 1D chains, however, in the structure of compound II, the four-membered ring ladders first interconnect via H2PO3 pseudo-pyramids to form a novel 2D double sheet with interleaving eight-membered ring openings and these layers are further pillared by HPO3 pseudo-pyramids to generate 3D open-framework. To our knowledge, compound II is the first 3D open-framework constructed from 1D four-membered ring ladders. Compared to indium phosphate with a pillared layer structure, the compound II is different in that the 2D layers are further connected by HPO3 pseudo-pyramids to generate the 3D framework. In the case of indium phosphate [In8(HPO4)14(H2O)6](H2O)5(H3O)(C3N2H5)3 [19], the 2D In/P/O layers with 4,6-rings are further linked together by InO6 octahedra to form the 3D open-framework with intersecting 14-ring channels. In indium phosphate [In6.8F8(H2O)2(PO4)4(HPO4)4][H2DETA]2[DETA]2H2O [20] with 16-membered ring channels, the 2D layers which are connected through corner-shared tancoite chain are pillared by InO4F2 units. The compound [In4(4,4 0 - bipy)3(HPO4)4(H2PO4)4] Æ 4H2O [21] which consists of 4,8-sheets are pillared through 4,4 0 -bipy ligands. Due to the small charge/radius ratio of In3+, the openframework structures of indium phosphites are more difficult to construct in comparison to the abundance of other metal phosphites. To date, only a purely inorganic framework indium phosphite In2(HPO3)3(H2O) was reported [22]. Its structure consists of an In2O10 dimer and pseudo-pyramidal HPO3, which are connected by sharing vertexes to form the 3D inorganic framework with a In/P ratio of 2/3. Presence of the In–O–In linkage leading to an In2O10 dimer in the framework is a noteworthy feature. The multiple hydrogen bonds play a key role in the formation and the stability of the open architecture. In compound II, in order to balance the negative charge of the anionic framework, the piperazine molecules are fully protonated. Each NH2 group forms two strong hydrogen bonds with the oxygen atoms of the framework as evidenced by the short N–H O distances such as ˚ , N(1)–H(1) O(2) 2.836 A ˚, N(1)–H(1) O(13) 2.836 A ˚ and N(2)–H(2) O(9) 3.298 A ˚. N(2)–H(2) O(8) 2.892 A 4. Conclusion In summary, two new indium phosphites (C2N2H10)[In(OH)3(HPO3)] I and (C4N2H12)[In2(HPO3)3(H2PO3)2] II have been synthesized under mild hydrothermal conditions using ethylenediamine and piperazine as structuredirecting agents, respectively. The organic amine molecule plays a central role in the formation of indium phosphites. Compound I displays a one-dimensional ladder structure containing edge-sharing four-member rings. Compound II displays a complex three-dimensional open-framework
containing multi-dimensional intersecting eight-membered ring channels. Interestingly, the three-dimensional openframework of compound II can be regarded as being constructed from the HPO3 pseudo-pyramids and a novel 2D double sheet which built by H2PO3 pseudo-pyramids and one-dimensional ladders that are similar to those observed in compound I. It is noted that compound II is the first organically templated indium phosphite with a threedimensional open-framework. Recent exploratory syntheses of metal phosphites reveal a rich structural chemistry. Our investigation shows that it is possible to prepare structurally complex open-framework indium phosphites possessing cavity size, limiting apertures, and framework densities rivaling those of the most open zeolites and aluminophosphates under appropriate reaction conditions. Further investigation of indium phosphites is in progress. Acknowledgments This work was supported by the State Basic Research Project (G2000077507), and the National Science Foundation of China (Nos. 29873017 and 20101004). References [1] A.K. Cheetham, G. Fe´rey, T. Loiseau, Angew. Chem. Int. Ed. 38 (1999) 3268. [2] A. Choudhury, S. Neeraj, S. Natarajan, C.N.R. Rao, J. Mater. Chem. 11 (2001) 1537. [3] S.H. Shi, W. Qian, G.H. Li, L. Wang, H.M. Yuan, J.N. Xu, G.S. Zhu, T.Y. Song, S.L. Qiu, J. Solid State Chem. 177 (2004) 3038, references therein. [4] G. Bonavia, J. Debord, R.C. Haushalter, D. Rose, J. Zubieta, Chem. Mater. 7 (1995) 1995. [5] N. Li, S.H. Xiang, J. Mater. Chem. 12 (2002) 1397. [6] W.S. Fu, L. Wang, Z. Shi, G.H. Li, X.B. Chen, Z.M. Dai, L. Yang, S.H. Feng, Cryst. Growth Des. 2 (2004) 297. [7] L. Wang, T.Y. Song, Y. Fan, Y. Wang, J.N. Xu, S.H. Shi, J. Solid State Chem. 179 (2006) 865. [8] G.M. Sheldrick, A Program for the Siemens Area Detector ABSorption Correction, University of Gottingen, Gottingen, Germany, 1997. [9] G.M. Sheldrick, SHELXTL-NT, Version 5.1, Bruker AXS Inc., Madison, WI, 1997. [10] D.T. Cromer, J.T. Waber, International Tables for X-ray Crystallography, vol. 4, Kynoch Press, Birmingham, AL, 1974 (Table 2.2A). [11] J.X. Pan, S.T. Zheng, G.Y. Yang, Micropor. Mesopor. Mater. 75 (2004) 129, references therein. [12] Z. Lin, J. Zhang, S. Zheng, G. Yang, J. Mater. Chem. 14 (2004) 1652. [13] T. Loiseau, F. Serpaggi, G. Fe´rey, Chem. Commun. 14 (1997) 1093. [14] T. Loiseau, G. Fe´rey, J. Mater. Chem. 6 (1996) 1073. [15] G. Fe´rey, J. Fluorine Chem. 7 (1995) 187. [16] A.A. Ayi, A. Choudhury, S. Natarajan, S. Neeraj, C.N.R. Rao, J. Mater. Chem. 11 (2001) 1181. [17] W.T.A. Harrison, Z. Bircsak, L. Hannooman, Z.H. Zhang, J. Solid State Chem. 136 (1998) 93. [18] I.D. Williams, J. Yu, Q. Gao, J. Chen, R. Xu, Chem. Commun. 14 (1997) 1273. [19] A.M. Chippindale, S.J. Brech, A.R. Cowley, W.M. Simpson, Chem. Mater. 8 (1996) 2259. [20] A. Thirumurugan, S. Natarajan, Dalton Trans. 17 (2003) 3387. [21] K.H. Lii, Y.F. Huang, Inorg. Chem. 38 (1999) 1348. [22] Z. Yi, C. Chen, S. Li, G. Li, H. Meng, Y. Cui, Y. Yang, W. Pang, Inorg. Chem. Commun. 8 (2005) 166.
Synthesis and characterization of two new organically templated indium phosphites built from one-dimensional ladders Li Wang, Tianyou Song, Jianing Xu, Ying Wang, Zhenfen Tian, Suhua Shi
*
Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Department of Chemistry, Jilin University, Changchun 130012, China Received 9 April 2006; received in revised form 4 July 2006; accepted 10 July 2006 Available online 23 August 2006
Abstract Two new indium phosphites, (C2N2H10)[In(OH)3(HPO3)] I and (C4N2H12)[In2(HPO3)3(H2PO3)2] II have been synthesized under mild hydrothermal conditions using ethylenediamine and piperazine as structure-directing agents, respectively and characterized by singlecrystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, TGA, ICP-AES and elemental analyses. Compound I displays a one-dimensional ladder structure containing edge-sharing four-member rings. Compound II displays a complex three-dimensional open-framework containing multi-dimensional intersecting eight-membered ring channels. It is noted that compound II is the first organically templated indium phosphite with three-dimensional open-framework. Another striking feature of II is that it possesses a novel twodimensional double sheet which is constructed by H2PO3 pseudo-pyramids and the one-dimensional ladders that are similar to those ˚ , b = 9.7106(9) A ˚, observed in I. Crystal data: I, H14C2N2O6PIn, M = 307.94, orthorhombic, space group P212121, a = 6.6483(6) A ˚ , V = 836.28(13) A ˚ 3, Z = 4, and II, H19C4N2O15P5In2, M = 719.70, monoclinic, space group P21/c, a = 9.4610(2) A ˚, c = 12.9537(12) A ˚ , c = 20.963(5) A ˚ , b = 100.186(1), V = 1835.6(7) A ˚ 3, Z = 4. b = 9.4028(2) A 2006 Elsevier Inc. All rights reserved. Keywords: Open-framework; Crystal structure; Hydrothermal synthesis; Indium phosphite; Organic template
1. Introduction In the past decades, metal phosphates with open architectures have been synthesized due to their rich structural chemistry and the potential applications in ion exchange, separation and catalysis [1]. These compounds occur as zero- (clusters), one- (chains or ladders), two- (layers), and three-dimensional structures. One of the strategies used for the design and synthesis of new materials in this system is the employment of organic amines as structuredirecting agents. The transfer of a variety of organic amines to inorganic products allows the formation of otherwise unattainable inorganic structures [1] and the transformation of zero- or one-dimensional structures to two-dimensional layers as well as three-dimensional structures with channels [2]. More recently, the pseudo-pyramidal phos*
Corresponding author. Tel.: +86 431 5168471; fax: +86 431 5671974. E-mail address: [email protected] (S. Shi).
1387-1811/$ - see front matter 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.micromeso.2006.07.008
phite [HPO3] group has been investigated as a possible replacement for the traditional phosphate tetrahedron with great success [3]. Compared to phosphate ½PO3 4 , the pyramidal hydrogen phosphite group ½HPO2 only 3 links three adjacent cations via P–O–M (M = metal) bonds, which might be expected to lead to a new class of compounds with interesting architectures. Since the vanadium phosphites with piperazinium cations as structurally directing agents [H2NC4H8NH2][(VO)3(HPO3)4(H2O)2] were synthesized by Zubieta et al. [4], a number of studies on the metal phosphites containing Zn, Co, Fe, V, Mn, and Cr have been carried out [3]. However, less exploratory work has been carried out on synthesizing the organically templated main group metal phosphates [5–7]. With an aim toward searching for novel organically templated phosphites, we conducted our study on the hydrothermal synthesis in indium–phosphite–amine systems. In our experiments, InCl3, H3PO3 and ethylenediamine (en) were selected as starting materials to prepare an indium
288
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
phosphite (C2N2H10)[In(OH)3(HPO3)] I, which has a onedimensional ladder structure. Our efforts were then focused on the replacement of ethylenediamine by other organic amines in order to make compound I with the one-dimensional ladder structure transform to two-dimensional layers or three-dimensional structures with channels. Finally, in the presence of piperazine a new three-dimensional indium phosphite (C4N2H12)[In2(HPO3)3(H2PO3)2] II with the multi-dimensional intersecting eight-membered ring channels was synthesized under hydrothermal conditions, which is constructed from the HPO3 pseudo-pyramids and onedimensional ladders that are similar to those observed in compound I. Herein we describe the synthesis, crystal structure and characterization of I and II, along with the effect of organic amine on formation of I and II. 2. Experimental 2.1. Materials and instrumentation All chemicals were obtained from commercial sources and used without further purification. The elemental analysis was conducted on a Perkin Elmer 2400 elemental analyzer. ICP-AES (inductively coupled plasma-atomic emission spectroscope) analysis was performed on a Perkin Elmer Optima 3300DV ICP instrument. Powder X-ray diffraction (XRD) data were obtained using SHIMADAZU XRD-6000 diffractometer with Cu-Ka radiation ˚ ), with the step size and the count time of (k = 1.5418 A 0.02 and 4 s, respectively. FT-IR spectra were recorded on a Nicolet Impact 410 spectrometer between 400 and 4000 cm1 using the KBr pellet method. Thermogravimetric analysis (TGA) was conducted on a SHIMADAZU DTG 60 thermogravimetric analyzer with a heating rate of 10 C min1 under nitrogen gas. 2.2. Synthesis Compound I was prepared from a reaction mixture of InCl3 Æ 4H2O, H3PO3, en and water with a molar ratio of 0.5:2.4:3.0:277. A typical synthesis procedure begins with mixing 0.16 g InCl3, 0.20 g H3PO3, 0.20 ml en, and 5 ml of water to form a reaction mixture. The mixture was stirred for 30 min at room temperature, then the mixture was transferred to a 23 ml PTFE-lined stainless-steel hydrothermal autoclave at a filling capacity of 22% and heated at 180 C for 7 d under autogenous pressure. Fine rod-shaped crystals, were filtered off, washed with water and dried at room temperature (yield = 60% based on In). Elemental analysis data were satisfactory (C obsd. (%), calcd. (%), 7.81, 7.79; H, 4.60, 4.55; N, 9.07, 9.09). The XRD pattern of I is consistent with the simulated one on the basis of single-crystal structure, indicating the phase purity of the as-synthesized sample (Fig. 1a). The compound II was prepared from a reaction mixture of InCl3 Æ 4H2O, H3PO3, piperazine and water with a molar ratio of 0.5:17.1:4.0:666. A typical synthesis procedure
Fig. 1. Simulated and experimental power X-ray diffraction patterns of compound I (a) and II (b).
begins with mixing 0.16 g InCl3, 1.40 g H3PO3, 0.80 g piperazine hexahydrate, and 12 ml of water to form a reaction mixture. The reaction mixture was stirred for 1 h at room temperature, then the mixture was transferred to a 23 ml PTFE-lined stainless-steel hydrothermal autoclave at a filling capacity of 52% and heated at 180 C for 7 d under autogenous pressure. The product containing block crystals was collected by filtration, washed thoroughly with distilled water, and dried in air at room temperature (51% yield based on In). The agreement between the experimental and simulated XRD patterns indicated the phase purity of the product (Fig. 1b). The difference in reflection intensities between the simulated and experimental patterns was due to the variation in preferred orientation for the powder sample. The ICP and elemental analysis results were also consistent with the theoretical values: C obsd. (%), calcd. (%), 6.70, 6.67; H, 2.72, 2.63; N, 3.90, 3.89; In, 31.89, 31.92; P, 21.58, 21.54. 2.3. Crystal structure determination Suitable single crystals with dimensions of 0.30 · 0.18 · 0.13 mm3 for I and 0.20 · 0.18 · 0.16 mm3 for II were carefully selected for single-crystal X-ray diffraction analysis.
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
289
Table 1 Crystallographic data for compounds I and II C4H19In2N2O15P5 Empirical formula H14C2N2O6PIn Formula weight 307.94 719.70 Crystal system Orthorhombic Monoclinic Space group P212121 P21/c ˚) a (A 6.6483(6) 9.461(2) ˚) b (A 9.7106(9) 9.4028(2) ˚) c (A 12.9537(12) 20.963(5) ˚) b (A 100.186(1) ˚ 3) ˚3 V (A 836.28(13) A 1835.6(7) Z 4 4 Dc (g cm3) 2.446 2.604 l (mm1) 3.016 3.028 Reflections 5052/1846 12,673/4515 collected/unique [Rint = 0.0517] [Rint = 0.1522] Data/restraints/ 1846/0/113 4515/3/270 parameters Goodness-of-fit 1.070 1.002 on F2 Final R indices R1 = 0.0329, R1 = 0.0377, [I > 2r(I)] wR2 = 0.0843 wR2 = 0.0702 Largest diff. 1.689 and 0.598 1.222 and 1.735 ˚ 3] peak/hole [e A P P P P R1 ¼ jjF o j jF cs jj= jF o j, wR2 ¼ ½wðF 2o F 2c Þ2 = ½wðF 2o Þ2 1=2 .
The intensity data were collected on a Siemens Smart CCD diffractometer equipped with graphite-monochromated ˚ ) radiation in the x scanning mode Mo-Ka (k = 0.71073 A at room temperature. No significant decay was observed during the data collection. Empirical absorption correction was applied using the SADABS program [8]. Data were processed on a Pentium PC using Bruker AXS Windows NT SHELXTL software package (version 5.10) [9,10]. The structure was solved by direct method and refined with full-matrix least squares. All the non-hydrogen atoms were refined anisotropically. Hydrogen atoms were placed geometrically and located in the difference Fourier map. Experimental details for the structural determinations of I and II are summarized in Table 1. CCDC-250379 and CCDC-600044 contain the supplementary crystallographic data for compound I and II, respectively. These data can be obtained free of charge at www.ccdc.cam.ac.uk [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (internat.) +44-1223/336-033; e-mail: [email protected]].
Fig. 2. Asymmetric unit of compound I with detailed labeling of the atoms.
nation geometry with average P–O bond length of ˚ and the terminal P–H bond length is 1.34(4) A ˚ 1.513(4) A which is similar to the P–H bond length reported in H3PO3 previously [4]. The existence of P–H bond is also verified by the IR spectrum, which exhibits strong absorption at 2397 cm1 [3]. There is one diprotonated ethylenediamine molecule in the asymmetric unit. The crystal structure of the title compound consists of [In(OH)3(HPO3)]2 infinite edge-sharing four-member ring ladders propagating along the a axis. The en cations are in the cavities of the structure delimited by three different chains, and both ionic interactions with the anionic chains exist (shown in Fig. 3a). The structure of the [In(OH)3(HPO3)]2 anionic chains is constructed from isolated InO3(OH)3 octahedra and pseudo-pyramidal (HPO3)2 phosphite oxoanions. The InO3(OH)3 octahedron shares the trans O1 and O4 atoms with the HPO3 pseudo-pyramid, forming an infinite chain of alternating octahedra and pseudo-pyramids. Each octahedron also shares its O5 atom with another HPO3 pseudo-pyramid belonging to a parallel chain, giving rise to the infinite ladder-like chains as shown in Fig. 3b.
3. Results and discussion 3.1. Structural description Crystal structure of (C2N2H10)[In(OH)3(HPO3)], I: The asymmetric unit of I contains 14 non-hydrogen atoms (1In, 1P, 8O, 2N and 2C) as shown in Fig. 2. The In atom adopts six coordination geometry with six oxygen atoms occupying each coordination site. The In–O bond lengths ˚ (av. 2.093(6) A ˚) are in the range of 2.042(3)–2.120(3) A and O–In–O angles are in the range of 85.06(11)– 173.33(12). The P atom adopts pseudo-pyramidal coordi-
Fig. 3. Polyhedral view of the structure of compound I along the [1 0 0] direction (a) and the one-dimensional ladder containing edge-sharing fourmembered rings along a axis (b).
290
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
Fig. 4. Asymmetric unit of compound II with detailed labeling of the atoms.
Crystal structure of (C4N2H12)[In2(HPO3)3(H2PO3)2], II: The asymmetric unit of II contains 28 non-hydrogen atoms, of which 22 belong to the framework and six belong to the guest species as shown in Fig. 4. There are two crystallographically independent indium and five phosphorus atoms. All In atoms are linked to the P atoms via oxygen bridges. The In–O bond lengths are in the range of ˚ and O–In–O angles are in the range 2.103(3)–2.165(3) A of 79.87(14)–176.99(12). All P atoms adopt pseudo-pyramidal coordination geometry, each bonded to three oxygen atoms and one hydrogen atom. All oxygen atoms bridge to the In atoms with the exception of two, which we have identified as terminal OH groups. The terminal P–H bond ˚ which are lengths are in the range of 1.32(4)–1.43(2) A similar to the P–H bond length reported in metal phosphite previously [11]. The existence of P–H bond is also verified by the IR spectrum, which exhibits strong absorption at 2415 cm1 [3]. The framework stoichiometry of [In2(HPO3)3(H2PO3)2] creates a net charge of 2, which is balanced by one diprotonated piperazine cation. The crystal structure of II may be viewed as the stacking of the [In2(HPO3)2(H2PO3)2] layers with HPO3 pseudo-pyramids as pillars to form the three-dimensional open-framework with multi-dimensional intersecting eight-membered
ring channels. As shown in Fig. 5b, the [In2(HPO3)2(H2PO3)2] layer is constructed by the HPO3 pseudo-pyramids and one-dimensional ladders which are built up from alternating two different types of four-membered rings. Though the four-membered rings both are composed of two InO6 octahedra and two HPO3 pseudo-pyramids, fused via In–O–P vertices, one of them is built from two In(1) atoms and two P(1) atoms, the other one from two In(2) atoms and two P(4) atoms. They alternately connect each other through O(4) and O(11) atoms to form the infinite ladders along the a axis (shown in Fig. 5a) which are similar to those found in compound I. These ladders are connected together in [0 0 1] plane in a very unusual and hitherto unreported way. As shown in Fig. 5b, the adjacent ladders stack paralleling the [1 0 0] direction and further interconnect via H2P(2)O3 and H2P(5)O3 pseudo-pyramids to generate 2D double sheets with interleaving eight-membered ring openings toward the [0 0 1] direction. A series of inorganic layers are held together in –ABAB– stacking sequence along the [0 0 1] direction. These are further linked by HP(3)O3 pseudo-pyramids which coordinate to In(1)O6 and In(2)O6 octahedra from four-membered rings on each of two adjacent layers, forming a three-dimensional openframework with intersecting eight-membered ring channels along the [1 0 0] and [0 1 0] directions, respectively (shown in Fig. 6). The diprotonated piperazine cations are located in the eight-membered ring channels and neutralize the negative charge of the inorganic framework. It is noted that the compound II is the first three-dimensional open-framework organically templated indium phosphite. 3.2. Discussion Compounds I and II are synthesized under hydrothermal conditions. It can be shown that the formation of compounds I and II is greatly influenced by the indium source and solvent. Using In2O3 as indium source, neither compound I nor compound II was obtained in similar experimental conditions. If the solvent was replaced by
Fig. 5. (Left) Polyhedral view of the one-dimensional ladder of compound II along a axis (a) and two-dimensional layer with interleaving eight-membered ring openings along [0 0 1] direction built from the one-dimensional ladders and H2PO3 pseudo-pyramids (b); (right) schematic drawing of one-dimensional ladder along a axis (a) and two-dimensional layer along [0 0 1] direction (b) of compound II.
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
291
Fig. 6. Polyhedral view of the structure of compound II with intersecting eight-membered ring channels along [1 0 0] and [0 1 0] directions, respectively.
1-butanol or glycol, the amorphous phase or thick gel were produced. The amount of water is the other factor that effects the crystallization of II. Using InCl3 Æ 4H2O as indium source, microcrystals of II were synthesized in the mixture with molar ratios of 0.5InCl3 Æ 4H2O: 17.1H3PO3:4.0piperazine:556H2O. When increasing the molar amount of water to 666 and keeping other conditions unchanged, block crystals of II were obtained, when decreasing the molar amount of water to less than 444, no crystals of II were prepared except for a thick gel. The IR spectra of compounds I and II show the bands corresponding to the vibrations of the organic amine cations and phosphite ions. The vibrational modes and their frequencies are given in Table 2. These results are similar to those found in other related compounds [3–7]. Thermogravimetric analyses of compounds I and II were carried out under nitrogen gas with a heating rate of 10 C min1. TGA for I shows two continual stages of weight loss with a total of 40.75% around 280–590 C, which is attribute to the decomposition of diprotonated en cations (calcd. 20.78% for one en cation per formula unit), the dehydration (calcd. 11.69% for two water molecules per formula unit) and a partial release (8.28%) of volatile phosphorus oxide [12] (approximately 17.86% of ‘‘P2O3’’ molecules per formula unit). XRD analysis shows the residue is amorphous. Thermogravimetric analysis shows a two-step weight Table 2 Selected bands (cm1) from the IR spectra for compounds I and II Assignment
I
II
m(NH3)+ m(–CH2–) m(HP) d(–NH3)+ d(–CH2–)
3152, 3057 (m) 2928 (m) 2402 (m) 1612 (m) 1516 (m), 1458 (w)
mas(PO3) ms(PO3) d(HP) ds(PO3) das(PO3)
1079 (s) 1015 (s) 920 (m) 598 (m) 495 (m)
3429, 3031 (m) 2819, 2794 (m) 2446, 2408 (m) 1605 (m) 1465 (m), 1336 (w) 1156, 1092 (s) 1028, 983 (s) 951 (m) 604, 580 (m) 476 (m)
m: stretching; d: deformation; s: symmetric; as: asymmetric; w: weak; m: medium; s: strong.
loss process for compound II. The first step occurring between 300 and 820 C is due to the decomposition of piperazinium cations. However, the observed mass loss (7.39%) is much lower than the expected value (12.22%). The lower reduction in mass loss is likely due to the retention of piperazine cations in the solid residue. The second event starting at 835 C with a mass loss of 51.52% is assigned to the removal of the residual piperazine species (4.83%) and the dehydration (calcd. 8.75% for 3.5 water molecules per formula unit) and a partial release (37.94%) of volatile phosphorus oxide (approximately 38.21% for the 2.5 mol of ‘‘P2O3’’ molecules per formula unit), respectively. The residue is amorphous and its phase is unidentified. The organic amine molecule plays a central role for the production of the open-framework materials. Two parameters relative to the nature of the amine are important: the size and shape of the amine (either spherical or linear) and its correlated ability to be protonated. Hence, the volume, the anisotropy of shape, and the charge will influence the structure and the porosity of the solid. Using several amines of varying chain lengths as templates, a series of open-framework gallium phosphates (designated ULM-n) were synthesized and it showed that the pore size increases with the carbon number [13–15]. Rao reported the transformation of low-dimensional zinc phosphates to complex open-framework structures by changing organic amine molecules [2,16]. Herein, using en as structure-directing agent, a one-dimensional ladder structure indium phosphite I was first synthesized, then with piperazine replacement of en, a new three-dimensional open-framework structure indium phosphite II was prepared under appropriate conditions. Due to the structure-directing effect of piperazine, the 1D four-membered ring ladders that are similar to those observed in I are held together with H2PO3 pseudo-pyramids to form the 2D double sheets. These layers are further pillared by HPO3 pseudo-pyramids forming a 3D openframework with intersecting eight-membered ring channels along the [1 0 0] and [0 1 0] directions, respectively. A large number of the edge-sharing four-member ring chains [17,18] which are constructed by alternating tetrahedra are reported in the literature, however, the ladders that are observed in compounds I and II constructed by
292
L. Wang et al. / Microporous and Mesoporous Materials 96 (2006) 287–292
alternating octahedra and pseudo-pyramids are very rare. The differences between them may derive from the different building unit and metal/phosphorous ratio. The structures of the compounds containing four-membered ring ladders are usual 1D chains, however, in the structure of compound II, the four-membered ring ladders first interconnect via H2PO3 pseudo-pyramids to form a novel 2D double sheet with interleaving eight-membered ring openings and these layers are further pillared by HPO3 pseudo-pyramids to generate 3D open-framework. To our knowledge, compound II is the first 3D open-framework constructed from 1D four-membered ring ladders. Compared to indium phosphate with a pillared layer structure, the compound II is different in that the 2D layers are further connected by HPO3 pseudo-pyramids to generate the 3D framework. In the case of indium phosphate [In8(HPO4)14(H2O)6](H2O)5(H3O)(C3N2H5)3 [19], the 2D In/P/O layers with 4,6-rings are further linked together by InO6 octahedra to form the 3D open-framework with intersecting 14-ring channels. In indium phosphate [In6.8F8(H2O)2(PO4)4(HPO4)4][H2DETA]2[DETA]2H2O [20] with 16-membered ring channels, the 2D layers which are connected through corner-shared tancoite chain are pillared by InO4F2 units. The compound [In4(4,4 0 - bipy)3(HPO4)4(H2PO4)4] Æ 4H2O [21] which consists of 4,8-sheets are pillared through 4,4 0 -bipy ligands. Due to the small charge/radius ratio of In3+, the openframework structures of indium phosphites are more difficult to construct in comparison to the abundance of other metal phosphites. To date, only a purely inorganic framework indium phosphite In2(HPO3)3(H2O) was reported [22]. Its structure consists of an In2O10 dimer and pseudo-pyramidal HPO3, which are connected by sharing vertexes to form the 3D inorganic framework with a In/P ratio of 2/3. Presence of the In–O–In linkage leading to an In2O10 dimer in the framework is a noteworthy feature. The multiple hydrogen bonds play a key role in the formation and the stability of the open architecture. In compound II, in order to balance the negative charge of the anionic framework, the piperazine molecules are fully protonated. Each NH2 group forms two strong hydrogen bonds with the oxygen atoms of the framework as evidenced by the short N–H O distances such as ˚ , N(1)–H(1) O(2) 2.836 A ˚, N(1)–H(1) O(13) 2.836 A ˚ and N(2)–H(2) O(9) 3.298 A ˚. N(2)–H(2) O(8) 2.892 A 4. Conclusion In summary, two new indium phosphites (C2N2H10)[In(OH)3(HPO3)] I and (C4N2H12)[In2(HPO3)3(H2PO3)2] II have been synthesized under mild hydrothermal conditions using ethylenediamine and piperazine as structuredirecting agents, respectively. The organic amine molecule plays a central role in the formation of indium phosphites. Compound I displays a one-dimensional ladder structure containing edge-sharing four-member rings. Compound II displays a complex three-dimensional open-framework
containing multi-dimensional intersecting eight-membered ring channels. Interestingly, the three-dimensional openframework of compound II can be regarded as being constructed from the HPO3 pseudo-pyramids and a novel 2D double sheet which built by H2PO3 pseudo-pyramids and one-dimensional ladders that are similar to those observed in compound I. It is noted that compound II is the first organically templated indium phosphite with a threedimensional open-framework. Recent exploratory syntheses of metal phosphites reveal a rich structural chemistry. Our investigation shows that it is possible to prepare structurally complex open-framework indium phosphites possessing cavity size, limiting apertures, and framework densities rivaling those of the most open zeolites and aluminophosphates under appropriate reaction conditions. Further investigation of indium phosphites is in progress. Acknowledgments This work was supported by the State Basic Research Project (G2000077507), and the National Science Foundation of China (Nos. 29873017 and 20101004). References [1] A.K. Cheetham, G. Fe´rey, T. Loiseau, Angew. Chem. Int. Ed. 38 (1999) 3268. [2] A. Choudhury, S. Neeraj, S. Natarajan, C.N.R. Rao, J. Mater. Chem. 11 (2001) 1537. [3] S.H. Shi, W. Qian, G.H. Li, L. Wang, H.M. Yuan, J.N. Xu, G.S. Zhu, T.Y. Song, S.L. Qiu, J. Solid State Chem. 177 (2004) 3038, references therein. [4] G. Bonavia, J. Debord, R.C. Haushalter, D. Rose, J. Zubieta, Chem. Mater. 7 (1995) 1995. [5] N. Li, S.H. Xiang, J. Mater. Chem. 12 (2002) 1397. [6] W.S. Fu, L. Wang, Z. Shi, G.H. Li, X.B. Chen, Z.M. Dai, L. Yang, S.H. Feng, Cryst. Growth Des. 2 (2004) 297. [7] L. Wang, T.Y. Song, Y. Fan, Y. Wang, J.N. Xu, S.H. Shi, J. Solid State Chem. 179 (2006) 865. [8] G.M. Sheldrick, A Program for the Siemens Area Detector ABSorption Correction, University of Gottingen, Gottingen, Germany, 1997. [9] G.M. Sheldrick, SHELXTL-NT, Version 5.1, Bruker AXS Inc., Madison, WI, 1997. [10] D.T. Cromer, J.T. Waber, International Tables for X-ray Crystallography, vol. 4, Kynoch Press, Birmingham, AL, 1974 (Table 2.2A). [11] J.X. Pan, S.T. Zheng, G.Y. Yang, Micropor. Mesopor. Mater. 75 (2004) 129, references therein. [12] Z. Lin, J. Zhang, S. Zheng, G. Yang, J. Mater. Chem. 14 (2004) 1652. [13] T. Loiseau, F. Serpaggi, G. Fe´rey, Chem. Commun. 14 (1997) 1093. [14] T. Loiseau, G. Fe´rey, J. Mater. Chem. 6 (1996) 1073. [15] G. Fe´rey, J. Fluorine Chem. 7 (1995) 187. [16] A.A. Ayi, A. Choudhury, S. Natarajan, S. Neeraj, C.N.R. Rao, J. Mater. Chem. 11 (2001) 1181. [17] W.T.A. Harrison, Z. Bircsak, L. Hannooman, Z.H. Zhang, J. Solid State Chem. 136 (1998) 93. [18] I.D. Williams, J. Yu, Q. Gao, J. Chen, R. Xu, Chem. Commun. 14 (1997) 1273. [19] A.M. Chippindale, S.J. Brech, A.R. Cowley, W.M. Simpson, Chem. Mater. 8 (1996) 2259. [20] A. Thirumurugan, S. Natarajan, Dalton Trans. 17 (2003) 3387. [21] K.H. Lii, Y.F. Huang, Inorg. Chem. 38 (1999) 1348. [22] Z. Yi, C. Chen, S. Li, G. Li, H. Meng, Y. Cui, Y. Yang, W. Pang, Inorg. Chem. Commun. 8 (2005) 166.