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Synthesis and structural characterization of a unique 3D coordination polymer [Pb(4-pya)2]n(4-pya = trans-4-pyridylacrylate)
Inorganic Chemistry Communications 10 (2007) 485–488 www.elsevier.com/locate/inoche
Synthesis and structural characterization of a unique 3D coordination polymer [Pb(4-pya)2]n(4-pya = trans-4-pyridylacrylate) Yan-Jun Zhu a, Zhi-Gang Ren a, Wen-Hua Zhang a, Yang Chen a, Hong-Xi Li a, Yong Zhang a, Jian-Ping Lang a,b,* a
b
Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, Jiangsu, PR China State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, PR China Received 13 December 2006; accepted 15 January 2007 Available online 19 January 2007
Abstract A novel lead(II)/4-pya coordination polymer [Pb(4-pya)2]n (1) (4-pya = trans-4-pyridylacrylate) was synthesized and structurally characterized. Single-crystal X-ray diffraction revealed that 1 consists of a 3D network constructed from the 4-pya bridging ligand and {Pb2O2} subunits, in which each eight-coordinated Pb(II) ion adopts a dodecahedral coordination geometry. The thermal and luminescent properties of 1 in the solid state were investigated. 2007 Elsevier B.V. All rights reserved. Keywords: trans-4-Pyridylacrylic acid; Lead; Crystal structure; Luminescence; Coordination polymer
In the past decade, the design and synthesis of multidimensional coordination polymers and metal–organic framework materials (MOFs) have been of an attractive area of research due to their intriguing topological structures as well as their unique application as functional materials [1–6]. Typically MOFs consist of metal centers that are tethered by multi-functional organic linkers, which give rise to a variety of building units and overall topologies. As a result, the selection of organic ligands with appropriate coordination sites linked by specific connectors is the key to forming metal–organic coordination polymers with fascinating structures and desirable properties. trans-4Pyridylacrylic acid (4-Hpya) is one of the useful ligands that possesses several interesting structural features in constructing coordination polymers. It has multiple coordina*
Corresponding author. Address: Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, Jiangsu, PR China. Tel: +86 512 65882865; fax: +86 512 65880089. E-mail address: [email protected] (J.-P. Lang). 1387-7003/$ - see front matter 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2007.01.009
tion sites that allow structures of higher dimensions. Furthermore, it has an asymmetric geometry that may lead to synthesize new materials for NLO devices when combining with metals [7]. The d-block or f-block/4-Hpya system has been previously examined [8] and demonstrated considerable structural variability. We have extended this investigation to main group metal ion-Pb(II) ion. Lead is still the most commonly encountered toxic metal pollutant in the environment, and therefore, there is a need for exploiting the unique coordination chemistry of Pb(II) [9] for the development of practical ligands as extractants, lead-poisoning treatment agents and sensors [10]. The absence of crystal field stabilization energy effects allows the Pb(II) ion to adopt a range of different coordination geometries not restricted to octahedral, tetrahedral or square planar. In light of the large radius and the occurrence of a stereochemically active lone pair of electrons, we anticipate that the coordination of 4-pya at Pb(II) center may lead to the formation of new coordination polymer with structure different from that of the transition metal/4-pya [8]. In this communication, we describe the synthesis, crystal
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structure, thermal and luminescent property of an interesting 3D Pb(II)/4-pya coordination polymer [Pb(4-pya)2]n (1). Complex 1 was obtained as colorless needle crystals by treatment of Pb(OAc)2 Æ 3H2O with 4-Hpya under the presence of Et3N in methanol solution [11]. The structure of the complex was identified by satisfactory elemental analysis, IR and X-ray diffraction [12]. In the IR spectrum of 1, the symmetric carboxylate C@O stretching vibrations appear as strong peaks at 1386 and 1420 cm 1, which suggests the presence of both bidentate and bridging carboxylate groups [8a,13]. Complex 1 crystallizes in the orthorhombic space group Pna21 and the asymmetric unit has one discrete [Pb(4pya)2] molecule. The Pb(1) atom in 1 is eight-coordinated by seven O atoms from five 4-pya ligands and one N atom from another 4-pya ligand, forming a dodecahedral coordination geometry (Fig. 1). There are two kinds of coordination modes for 4-pya ligands in the structure. One mode is that the 4-pya ligand chelates the Pb(1) ion via O(1) and O(2) and links the Pb(1A) and Pb(1B) via O(1) atom and its pyridyl group remains intact. The other is that the 4-
pya ligand chelates the Pb(1) ion via O(3) and O(4) and connects the Pb(1A) atom via O(3) atom and its pyridyl nitrogen atom coordinates at one Pb center. Both coordination modes are unprecedented in metal/4-pya complexes. For 1, there is no clear gap in the coordination sphere of the Pb(II) ion, so a holodirected geometry is observed [14]. As shown in Fig. 1, O(1C) and O(1D) act as l-oxo bridging between Pb(1) and Pb(1C) to form a centrosymmetric Pb2O2 plane. The Pb(1) Pb(1C) contact within this ˚ , which is too long to include metal–metal plane is 4.320 A interaction [14c]. Based on the head-to-tail arranged 4-pya anions, the Pb2O2 plane was linked to construct [Pb2(4pya)8]4 rings. The [Pb2(4-pya)8]4 rings were further extended into a 2D network by sharing Pb(II) joints and the 4-pya ligand. This 2D network was further linked to form a 3D supramolecular architecture through the l3-O and l-O atoms of the carboxylate groups of 4-pya anions (Fig. 2). Interestingly, along the c axis, four Pb(II) atoms are located at the four corners of a defective double cubane (two cubanes sharing one face and each missing one vertex) and bridged by means of four l3-O atoms and two l-O
˚ ) and angles (): Pb(1)–O(1) Fig. 1. The coordination environment of the Pb(II) ion in 1 Hydrogen atoms are omitted for clarity. Selected bond lengths (A 2.677(5); Pb(1)–O(1D) 2.817(3); Pb(1)–O(1C) 2.744(3); Pb(1)–O(2) 2.629(4); Pb(1)–O(3A) 2.863(6); Pb(1)–O(3) 2.592(6); Pb(1)–O(4A) 2.468(4); Pb(1)– N(2B) 2.635(4); O(4A)–Pb(1)–O(3) 81.07(15); O(4A)–Pb(1)–O(2) 123.16(14); O(3)–Pb(1)–O(2) 144.28(14); O(4A)–Pb(1)–N(2B) 72.15(14); O(3)–Pb(1)– N(2B) 88.63(14); O(2)–Pb(1)–N(2B) 76.72(13); O(4A)–Pb(1)–O(1) 109.46(14); O(3)–Pb(1)–O(1) 153.66(11); O(2)–Pb(1)–O(1) 49.28(11); N(2B)–Pb(1)–O(1) 117.41(12); O(4A)–Pb(1)–O(1C) 116.64(13); O(3)–Pb(1)–O(1C) 76.44(14); O(2)–Pb(1)–O(1) 108.43(11); N(2B)–Pb(1)–O(1) 160.62(17); O(1)–Pb(1)–O(1C) 77.27(10). Symmetry code: A: x, y, z 1; B: x 1/2, y + 3/2, z; C: x + 2, y + 1, z + 1; D: x, y, z + 1.
Y.-J. Zhu et al. / Inorganic Chemistry Communications 10 (2007) 485–488
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Fig. 2. The 3D framework of complex 1. Hydrogen atoms are omitted for clarity.
atoms. It is worth noted that only a limited number of dicubane-like structures formed from Pb–O bond and bridging O atoms from carboxylate group were reported [15]. By sharing the Pb2O2 planes, this kind of dicubane was further linked to form a 1D dicubane-like chain along the c axis (Fig. 3). Because of the existence of the different coordination modes of 4-pya ligands in 1, the Pb–O bond distances are different. The average Pb-l3-O(1) bond length (2.746(4) ˚ ) is comparable to those of the corresponding ones in A ˚) [Pb2(PhOCH2CO2)4(H2O)]n (2.774(8) A [16a] and ˚ ) [16b]. The Pb(1)–O(3) [Pb6(iPrCO2)12(H2O)4] (2.76(2) A ˚ longer than that of Pb(1A)–O(3) bond, length is 0.27 A ˚ ) is slightly longer than and their mean value (2.728(6) A those of the corresponding ones in [Pb2(PhOCH2CO2)4˚ ) and [Pb6(iPrCO2)12(H2O)4] (2.54(2) (H2O)]n (2.713(9) A
˚ ). The Pb(1)–O(2) distance is 0.143 A ˚ longer than that A ˚ ) is of Pb(1)–O(4) bond, but their mean value (2.558(4) A close to those of the corresponding ones in [Pb2(PhOCH2˚ ) and [Pb6(iPrCO2)12(H2O)4] CO2)4(H2O)]n (2.524(10) A ˚ ). Such a difference may be attributed to the (2.53(2) A repulsion of the lone pair electrons with the electrons of the carboxylate oxygen atoms. The Pb(1)–N distance is ˚ , which is comparable to that reported in the 2.635(4) A complex [Pb(3-PYD)2]n [3-HPYD = 3-(3-pyridyl)acrylic ˚ ) [17a] and 0.1 A ˚ shorter than that in the acid] (2.652(8) A complex Pb2[O2CCH2N(CH2PO3)(CH2PO3H)] Æ H2O [17b]. The thermogravimetric analysis revealed that 1 was stable up to 320 C. The TGA curve of 1 displayed two stages of decomposition. The total weight loss of 59.3% in the range of 320–620 C corresponds roughly to the loss of two 4-pya ligands (calcd. 58.8%). The remaining weight
Fig. 3. The 1D incomplete-cubane chain of 1 extending along the c axis. All carbon and hydrogen atoms are omitted for clarity. Symmetry code: A: x, y, z + 1; B: x + 2, y + 1, z + 3/2; C: x + 2, y + 1, z + 1; D: x, y, z 1/2.
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Fig. 4. The emission (kex = 370 nm) spectrum of 1 in the solid state at ambient temperature.
of 40.7% was assumed to be the final product of Pb (calcd. 41.2%). The luminescent property of 1 was investigated in solid state at room temperature (Fig. 4). Complex 1 exhibited two fluorescence peaks at 418 and 438 nm when excited at 370 nm. We assumed that the emissions may be arising from the Pb2+ lone pair to ligand charge transfer [18]. Acknowledgements This work was financially supported by the NNSF (No. 20525101), the NSF of Jiangsu Province (No. BK2004205), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20050285004), the State Key Laboratory of Organometallic Chemistry of SIOC (No. 06-26) and the Qin-Lan Project of Jiangsu Province in China. The authors also thank Prof. Zhong-Ni Chen of FJIRSM for his assistance in the measurement of luminescent properties of the title compound. Appendix A. Supplementary material CCDC 609976 contains the supplementary crystallographic data for (1). These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: [email protected]. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.inoche. 2007.01.009. References [1] J.L.C. Rowsell, A.R. Millward, K.S. Park, O.M. Yaghi, J. Am. Chem. Soc. 126 (2004) 5666. [2] M.L. Tong, X.M. Chen, S.R. Batten, J. Am. Chem. Soc. 125 (2003) 16170. [3] C.F. Wang, J.L. Zuo, B.M. Bartlett, Y. Song, J.R. Long, X.Z. You, J. Am. Chem. Soc. 128 (2006) 7162. [4] L. Pan, E.B. Woodlock, X. Wang, Inorg. Chem. 39 (2000) 4174.
[5] P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem. Int. Ed. 38 (1999) 3268. [6] E.Q. Gao, S.Q. Bai, Z.M. Wang, C.H. Yan, J. Am. Chem. Soc. 125 (2003) 4984. [7] L. Pan, X.Y. Huang, J. Li, Y.G. Wu, N.W. Zheng, Angew. Chem. Int. Ed. 39 (2000) 527. [8] (a) O.R. Evans, W.B. Lin, Chem. Mater. 13 (2001) 2705; (b) J. Zhang, R.G. Xiong, J.L. Zuo, X.Z. You, Chem. Commun. (2000) 1495; (c) Y.H. Liu, C.S. Lin, S.Y. Chen, H.L. Tsai, C.H. Ueng, K.L. Lu, J. Solid State Chem. 157 (2001) 166; (d) Y.J. Zhu, J.X. Chen, W.H. Zhang, Z.G. Ren, Y. Zhang, J.P. Lang, S.W. Ng, J. Organomet. Chem. 690 (2005) 3479. [9] (a) E.S. Claudio, H.A. Godwin, J.S. Prog, Magyar, Inorg. Chem. 53 (2003) 1; (b) B.M. Bridgewater, G. Parkin, J. Am. Chem. Soc. 122 (2000) 7140; (c) S. Hino, M. Brynda, A.D. Phillips, P.P. Power, Angew. Chem. Int. Ed. 43 (2004) 2655. [10] (a) M. Crego-Calama, D.N. Reinhoudt, Adv. Mater. 13 (2001) 1171; (b) J.W. Liu, Y. Lu, J. Am. Chem. Soc. 125 (2003) 6642; (c) R. Metivier, I. Leray, B. Valeur, Chem. Commun. (2003) 996. [11] Synthesis of 1: To a suspension containing 4-Hpya (0.030 g, 0.2 mmol) in MeOH (2 ml) was added a small amount of Et3N. The resulting colorless solution was then treated with a solution of Pb(OAc)2 Æ 3H2O (0.038 g, 0.1 mmol) in 5 ml of MeOH. The mixture was stirred mildly for 15 min before filtration. Colorless needles of 1 were obtained by slow evaporation of MeOH and/or H2O in the filtrate at room temperature three days later. The crystals were collected by filtration, washed by MeOH and Et2O and dried in vacuo. Yield: 0.038 g (76%). Anal. Calcd. for C16H12PbN2O4: C, 38.17; H, 2.40; N, 5.56. Found: C, 37.80; H, 2.30; N, 5.75%. IR (KBr disk, cm 1): 2965(m), 1642(s), 1606(s), 1563(s), 1536(s), 1420(s), 1386(s), 1262(m), 977(m), 822(s), 729(m), 588(m). [12] Crystal data for 1: C16H12PbN2O4, Mr = 503.47, colorless crystal (0.30 · 0.13 · 0.10 mm), Orthorhombic, space group Pna21, ˚ , b = 25.051(5) A ˚ , c = 4.2579 A ˚ , V = 1513.0(5) A ˚ 3, a = 14.185(3) A Z = 4, T = 193 K, Dcalcd. = 2.210 g cm 1, l = 11.17 cm 1, R(wR) = 0.0239(0.0460) and GOF = 1.097 for 3098 reflections with I > 2.00r(I). The crystal structure of 1 was solved by direct methods using S HELXS-97 program and refined on F2 by full-matrix leastsquares using SHELXL-97 program. All non-H atoms were refined anisotropically while all H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with Uiso(H) = 1.2 Ueq. [13] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination compounds, Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry, fifth ed., Wiley, New York, 1997, p. 60. [14] (a) A.A. Saudi, F. Marandi, A. Ramazani, E. Ahmadi, A. Morsali, C.R. Chimie 8 (2005) 157; (b) J.M. Harrowfield, H. Miyamae, B.W. Skelton, A.A. Soudi, A.H. White, Aust. J. Chem. 49 (1996) 1121; (c) J.M. Harrowfield, B.W. Skelton, A.H. White, J. Chem. Soc. Dalton Trans. (1993) 2011. [15] (a) M.W. Wemple, D.M. Adams, K. Folting, D.N. Hendrickson, G. Christou, J. Am. Chem. Soc. 117 (1995) 7275; (b) G.S. Papaefstathiou, A. Escuer, C.P. Raptopoulou, A. Terzis, S.P. Perlepes, R. Vicente, Eur. J. Inorg. Chem. (2001) 1567. [16] (a) L.B. Archer, M.J. Hampden-Smith, E.N. Duesler, Polyhedron 15 (1996) 929; (b) G.D. Fallon, L. Spiccia, B.O. West, Q. Zhang, Polyhedron 16 (1997) 19. [17] (a) X.J. Li, R. Cao, Y.Q. Sun, W.H. Bi, X. Li, Y.Q. Wang, Eur. J. Inorg. Chem. (2005) 321; (b) J.L. Song, J.G. Mao, Y.Q. Sun, H.Y. Zeng, R.K. Kremer, A. Clearfield, J. Solid State Chem. 177 (2004) 633. [18] H.G. Zhu, Y. Xu, Z. Yu, Q.J. Wu, H.K. Fun, X.Z. You, Polyhedron 18 (1999) 3491.
Synthesis and structural characterization of a unique 3D coordination polymer [Pb(4-pya)2]n(4-pya = trans-4-pyridylacrylate) Yan-Jun Zhu a, Zhi-Gang Ren a, Wen-Hua Zhang a, Yang Chen a, Hong-Xi Li a, Yong Zhang a, Jian-Ping Lang a,b,* a
b
Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, Jiangsu, PR China State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, PR China Received 13 December 2006; accepted 15 January 2007 Available online 19 January 2007
Abstract A novel lead(II)/4-pya coordination polymer [Pb(4-pya)2]n (1) (4-pya = trans-4-pyridylacrylate) was synthesized and structurally characterized. Single-crystal X-ray diffraction revealed that 1 consists of a 3D network constructed from the 4-pya bridging ligand and {Pb2O2} subunits, in which each eight-coordinated Pb(II) ion adopts a dodecahedral coordination geometry. The thermal and luminescent properties of 1 in the solid state were investigated. 2007 Elsevier B.V. All rights reserved. Keywords: trans-4-Pyridylacrylic acid; Lead; Crystal structure; Luminescence; Coordination polymer
In the past decade, the design and synthesis of multidimensional coordination polymers and metal–organic framework materials (MOFs) have been of an attractive area of research due to their intriguing topological structures as well as their unique application as functional materials [1–6]. Typically MOFs consist of metal centers that are tethered by multi-functional organic linkers, which give rise to a variety of building units and overall topologies. As a result, the selection of organic ligands with appropriate coordination sites linked by specific connectors is the key to forming metal–organic coordination polymers with fascinating structures and desirable properties. trans-4Pyridylacrylic acid (4-Hpya) is one of the useful ligands that possesses several interesting structural features in constructing coordination polymers. It has multiple coordina*
Corresponding author. Address: Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123, Jiangsu, PR China. Tel: +86 512 65882865; fax: +86 512 65880089. E-mail address: [email protected] (J.-P. Lang). 1387-7003/$ - see front matter 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2007.01.009
tion sites that allow structures of higher dimensions. Furthermore, it has an asymmetric geometry that may lead to synthesize new materials for NLO devices when combining with metals [7]. The d-block or f-block/4-Hpya system has been previously examined [8] and demonstrated considerable structural variability. We have extended this investigation to main group metal ion-Pb(II) ion. Lead is still the most commonly encountered toxic metal pollutant in the environment, and therefore, there is a need for exploiting the unique coordination chemistry of Pb(II) [9] for the development of practical ligands as extractants, lead-poisoning treatment agents and sensors [10]. The absence of crystal field stabilization energy effects allows the Pb(II) ion to adopt a range of different coordination geometries not restricted to octahedral, tetrahedral or square planar. In light of the large radius and the occurrence of a stereochemically active lone pair of electrons, we anticipate that the coordination of 4-pya at Pb(II) center may lead to the formation of new coordination polymer with structure different from that of the transition metal/4-pya [8]. In this communication, we describe the synthesis, crystal
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structure, thermal and luminescent property of an interesting 3D Pb(II)/4-pya coordination polymer [Pb(4-pya)2]n (1). Complex 1 was obtained as colorless needle crystals by treatment of Pb(OAc)2 Æ 3H2O with 4-Hpya under the presence of Et3N in methanol solution [11]. The structure of the complex was identified by satisfactory elemental analysis, IR and X-ray diffraction [12]. In the IR spectrum of 1, the symmetric carboxylate C@O stretching vibrations appear as strong peaks at 1386 and 1420 cm 1, which suggests the presence of both bidentate and bridging carboxylate groups [8a,13]. Complex 1 crystallizes in the orthorhombic space group Pna21 and the asymmetric unit has one discrete [Pb(4pya)2] molecule. The Pb(1) atom in 1 is eight-coordinated by seven O atoms from five 4-pya ligands and one N atom from another 4-pya ligand, forming a dodecahedral coordination geometry (Fig. 1). There are two kinds of coordination modes for 4-pya ligands in the structure. One mode is that the 4-pya ligand chelates the Pb(1) ion via O(1) and O(2) and links the Pb(1A) and Pb(1B) via O(1) atom and its pyridyl group remains intact. The other is that the 4-
pya ligand chelates the Pb(1) ion via O(3) and O(4) and connects the Pb(1A) atom via O(3) atom and its pyridyl nitrogen atom coordinates at one Pb center. Both coordination modes are unprecedented in metal/4-pya complexes. For 1, there is no clear gap in the coordination sphere of the Pb(II) ion, so a holodirected geometry is observed [14]. As shown in Fig. 1, O(1C) and O(1D) act as l-oxo bridging between Pb(1) and Pb(1C) to form a centrosymmetric Pb2O2 plane. The Pb(1) Pb(1C) contact within this ˚ , which is too long to include metal–metal plane is 4.320 A interaction [14c]. Based on the head-to-tail arranged 4-pya anions, the Pb2O2 plane was linked to construct [Pb2(4pya)8]4 rings. The [Pb2(4-pya)8]4 rings were further extended into a 2D network by sharing Pb(II) joints and the 4-pya ligand. This 2D network was further linked to form a 3D supramolecular architecture through the l3-O and l-O atoms of the carboxylate groups of 4-pya anions (Fig. 2). Interestingly, along the c axis, four Pb(II) atoms are located at the four corners of a defective double cubane (two cubanes sharing one face and each missing one vertex) and bridged by means of four l3-O atoms and two l-O
˚ ) and angles (): Pb(1)–O(1) Fig. 1. The coordination environment of the Pb(II) ion in 1 Hydrogen atoms are omitted for clarity. Selected bond lengths (A 2.677(5); Pb(1)–O(1D) 2.817(3); Pb(1)–O(1C) 2.744(3); Pb(1)–O(2) 2.629(4); Pb(1)–O(3A) 2.863(6); Pb(1)–O(3) 2.592(6); Pb(1)–O(4A) 2.468(4); Pb(1)– N(2B) 2.635(4); O(4A)–Pb(1)–O(3) 81.07(15); O(4A)–Pb(1)–O(2) 123.16(14); O(3)–Pb(1)–O(2) 144.28(14); O(4A)–Pb(1)–N(2B) 72.15(14); O(3)–Pb(1)– N(2B) 88.63(14); O(2)–Pb(1)–N(2B) 76.72(13); O(4A)–Pb(1)–O(1) 109.46(14); O(3)–Pb(1)–O(1) 153.66(11); O(2)–Pb(1)–O(1) 49.28(11); N(2B)–Pb(1)–O(1) 117.41(12); O(4A)–Pb(1)–O(1C) 116.64(13); O(3)–Pb(1)–O(1C) 76.44(14); O(2)–Pb(1)–O(1) 108.43(11); N(2B)–Pb(1)–O(1) 160.62(17); O(1)–Pb(1)–O(1C) 77.27(10). Symmetry code: A: x, y, z 1; B: x 1/2, y + 3/2, z; C: x + 2, y + 1, z + 1; D: x, y, z + 1.
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Fig. 2. The 3D framework of complex 1. Hydrogen atoms are omitted for clarity.
atoms. It is worth noted that only a limited number of dicubane-like structures formed from Pb–O bond and bridging O atoms from carboxylate group were reported [15]. By sharing the Pb2O2 planes, this kind of dicubane was further linked to form a 1D dicubane-like chain along the c axis (Fig. 3). Because of the existence of the different coordination modes of 4-pya ligands in 1, the Pb–O bond distances are different. The average Pb-l3-O(1) bond length (2.746(4) ˚ ) is comparable to those of the corresponding ones in A ˚) [Pb2(PhOCH2CO2)4(H2O)]n (2.774(8) A [16a] and ˚ ) [16b]. The Pb(1)–O(3) [Pb6(iPrCO2)12(H2O)4] (2.76(2) A ˚ longer than that of Pb(1A)–O(3) bond, length is 0.27 A ˚ ) is slightly longer than and their mean value (2.728(6) A those of the corresponding ones in [Pb2(PhOCH2CO2)4˚ ) and [Pb6(iPrCO2)12(H2O)4] (2.54(2) (H2O)]n (2.713(9) A
˚ ). The Pb(1)–O(2) distance is 0.143 A ˚ longer than that A ˚ ) is of Pb(1)–O(4) bond, but their mean value (2.558(4) A close to those of the corresponding ones in [Pb2(PhOCH2˚ ) and [Pb6(iPrCO2)12(H2O)4] CO2)4(H2O)]n (2.524(10) A ˚ ). Such a difference may be attributed to the (2.53(2) A repulsion of the lone pair electrons with the electrons of the carboxylate oxygen atoms. The Pb(1)–N distance is ˚ , which is comparable to that reported in the 2.635(4) A complex [Pb(3-PYD)2]n [3-HPYD = 3-(3-pyridyl)acrylic ˚ ) [17a] and 0.1 A ˚ shorter than that in the acid] (2.652(8) A complex Pb2[O2CCH2N(CH2PO3)(CH2PO3H)] Æ H2O [17b]. The thermogravimetric analysis revealed that 1 was stable up to 320 C. The TGA curve of 1 displayed two stages of decomposition. The total weight loss of 59.3% in the range of 320–620 C corresponds roughly to the loss of two 4-pya ligands (calcd. 58.8%). The remaining weight
Fig. 3. The 1D incomplete-cubane chain of 1 extending along the c axis. All carbon and hydrogen atoms are omitted for clarity. Symmetry code: A: x, y, z + 1; B: x + 2, y + 1, z + 3/2; C: x + 2, y + 1, z + 1; D: x, y, z 1/2.
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Fig. 4. The emission (kex = 370 nm) spectrum of 1 in the solid state at ambient temperature.
of 40.7% was assumed to be the final product of Pb (calcd. 41.2%). The luminescent property of 1 was investigated in solid state at room temperature (Fig. 4). Complex 1 exhibited two fluorescence peaks at 418 and 438 nm when excited at 370 nm. We assumed that the emissions may be arising from the Pb2+ lone pair to ligand charge transfer [18]. Acknowledgements This work was financially supported by the NNSF (No. 20525101), the NSF of Jiangsu Province (No. BK2004205), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20050285004), the State Key Laboratory of Organometallic Chemistry of SIOC (No. 06-26) and the Qin-Lan Project of Jiangsu Province in China. The authors also thank Prof. Zhong-Ni Chen of FJIRSM for his assistance in the measurement of luminescent properties of the title compound. Appendix A. Supplementary material CCDC 609976 contains the supplementary crystallographic data for (1). These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: [email protected]. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.inoche. 2007.01.009. References [1] J.L.C. Rowsell, A.R. Millward, K.S. Park, O.M. Yaghi, J. Am. Chem. Soc. 126 (2004) 5666. [2] M.L. Tong, X.M. Chen, S.R. Batten, J. Am. Chem. Soc. 125 (2003) 16170. [3] C.F. Wang, J.L. Zuo, B.M. Bartlett, Y. Song, J.R. Long, X.Z. You, J. Am. Chem. Soc. 128 (2006) 7162. [4] L. Pan, E.B. Woodlock, X. Wang, Inorg. Chem. 39 (2000) 4174.
[5] P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem. Int. Ed. 38 (1999) 3268. [6] E.Q. Gao, S.Q. Bai, Z.M. Wang, C.H. Yan, J. Am. Chem. Soc. 125 (2003) 4984. [7] L. Pan, X.Y. Huang, J. Li, Y.G. Wu, N.W. Zheng, Angew. Chem. Int. Ed. 39 (2000) 527. [8] (a) O.R. Evans, W.B. Lin, Chem. Mater. 13 (2001) 2705; (b) J. Zhang, R.G. Xiong, J.L. Zuo, X.Z. You, Chem. Commun. (2000) 1495; (c) Y.H. Liu, C.S. Lin, S.Y. Chen, H.L. Tsai, C.H. Ueng, K.L. Lu, J. Solid State Chem. 157 (2001) 166; (d) Y.J. Zhu, J.X. Chen, W.H. Zhang, Z.G. Ren, Y. Zhang, J.P. Lang, S.W. Ng, J. Organomet. Chem. 690 (2005) 3479. [9] (a) E.S. Claudio, H.A. Godwin, J.S. Prog, Magyar, Inorg. Chem. 53 (2003) 1; (b) B.M. Bridgewater, G. Parkin, J. Am. Chem. Soc. 122 (2000) 7140; (c) S. Hino, M. Brynda, A.D. Phillips, P.P. Power, Angew. Chem. Int. Ed. 43 (2004) 2655. [10] (a) M. Crego-Calama, D.N. Reinhoudt, Adv. Mater. 13 (2001) 1171; (b) J.W. Liu, Y. Lu, J. Am. Chem. Soc. 125 (2003) 6642; (c) R. Metivier, I. Leray, B. Valeur, Chem. Commun. (2003) 996. [11] Synthesis of 1: To a suspension containing 4-Hpya (0.030 g, 0.2 mmol) in MeOH (2 ml) was added a small amount of Et3N. The resulting colorless solution was then treated with a solution of Pb(OAc)2 Æ 3H2O (0.038 g, 0.1 mmol) in 5 ml of MeOH. The mixture was stirred mildly for 15 min before filtration. Colorless needles of 1 were obtained by slow evaporation of MeOH and/or H2O in the filtrate at room temperature three days later. The crystals were collected by filtration, washed by MeOH and Et2O and dried in vacuo. Yield: 0.038 g (76%). Anal. Calcd. for C16H12PbN2O4: C, 38.17; H, 2.40; N, 5.56. Found: C, 37.80; H, 2.30; N, 5.75%. IR (KBr disk, cm 1): 2965(m), 1642(s), 1606(s), 1563(s), 1536(s), 1420(s), 1386(s), 1262(m), 977(m), 822(s), 729(m), 588(m). [12] Crystal data for 1: C16H12PbN2O4, Mr = 503.47, colorless crystal (0.30 · 0.13 · 0.10 mm), Orthorhombic, space group Pna21, ˚ , b = 25.051(5) A ˚ , c = 4.2579 A ˚ , V = 1513.0(5) A ˚ 3, a = 14.185(3) A Z = 4, T = 193 K, Dcalcd. = 2.210 g cm 1, l = 11.17 cm 1, R(wR) = 0.0239(0.0460) and GOF = 1.097 for 3098 reflections with I > 2.00r(I). The crystal structure of 1 was solved by direct methods using S HELXS-97 program and refined on F2 by full-matrix leastsquares using SHELXL-97 program. All non-H atoms were refined anisotropically while all H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with Uiso(H) = 1.2 Ueq. [13] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination compounds, Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry, fifth ed., Wiley, New York, 1997, p. 60. [14] (a) A.A. Saudi, F. Marandi, A. Ramazani, E. Ahmadi, A. Morsali, C.R. Chimie 8 (2005) 157; (b) J.M. Harrowfield, H. Miyamae, B.W. Skelton, A.A. Soudi, A.H. White, Aust. J. Chem. 49 (1996) 1121; (c) J.M. Harrowfield, B.W. Skelton, A.H. White, J. Chem. Soc. Dalton Trans. (1993) 2011. [15] (a) M.W. Wemple, D.M. Adams, K. Folting, D.N. Hendrickson, G. Christou, J. Am. Chem. Soc. 117 (1995) 7275; (b) G.S. Papaefstathiou, A. Escuer, C.P. Raptopoulou, A. Terzis, S.P. Perlepes, R. Vicente, Eur. J. Inorg. Chem. (2001) 1567. [16] (a) L.B. Archer, M.J. Hampden-Smith, E.N. Duesler, Polyhedron 15 (1996) 929; (b) G.D. Fallon, L. Spiccia, B.O. West, Q. Zhang, Polyhedron 16 (1997) 19. [17] (a) X.J. Li, R. Cao, Y.Q. Sun, W.H. Bi, X. Li, Y.Q. Wang, Eur. J. Inorg. Chem. (2005) 321; (b) J.L. Song, J.G. Mao, Y.Q. Sun, H.Y. Zeng, R.K. Kremer, A. Clearfield, J. Solid State Chem. 177 (2004) 633. [18] H.G. Zhu, Y. Xu, Z. Yu, Q.J. Wu, H.K. Fun, X.Z. You, Polyhedron 18 (1999) 3491.