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1D Chain and 3D framework of silver(I) organo-metallic polymers self-assembled with triptycene
Polyhedron 26 (2007) 2455–2460 www.elsevier.com/locate/poly
1D Chain and 3D framework of silver(I) organo-metallic polymers self-assembled with triptycene Ming Wen a,*, Megumu Munakata b, Yi-Zhi Li c, Yusaku Suenaga b, Takayoshi Kuroda-Sowa b, Masahiko Maekawa d, Manabu Anahata b a Department of Chemistry, Tongji University, 1239# SiPing Road, Shanghai 200092, China Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, China d Research Institute for Science and Technology, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan b
c
Received 11 September 2006; accepted 12 December 2006 Available online 10 January 2007
Abstract For the purpose of investigating the coordination behavior of sterically congested alkenes and exploring the possibility of non-planar complexation in the polycyclic aromatic system for formation of extended polymeric networks, triptycene (tpty) has been studied with regard to its complexation with the silver(I) ion. The crystal structures of [Ag(tpty)(THF)2](ClO4) (1) and [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) have been determined by single-crystal X-ray diffraction. The polycyclic aromatic hydrocarbon triptycene is found to offer a potential site for complexation, which can be utilized to generate an interesting array of organo-metallic polymers with onedimensional (1D) chain and three-dimensional (3D) porous frameworks. 2007 Elsevier Ltd. All rights reserved. Keywords: Silver(I) complex; Triptycene; Porous complex
1. Introduction Silver p-complexes of polycyclic aromatic hydrocarbons exhibit stereochemical features of exceptional interest. Such examples are the conformational variability of silver-polycyclic aromatic complexes with a vast range of open frameworks and layered materials in which the ionic inorganic species is occluded within an organic framework [1]. Aside from the interest in these fascinating structures, the new hybrid organic–inorganic layered and chain materials have often shown unique donor–acceptor electronic properties due to the overall planarity of the organic molecules and the extended delocalized p-systems [2,3]. In an effort to establish strategies aimed at the design of solids with large pores and to obtain a consequence of known structures of non-planar aromatic species, we are *
Corresponding author. Fax: +86 21 65982287. E-mail address: [email protected] (M. Wen).
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currently engaged in a detailed study of the coordination chemistry of triptycene (tpty). Triptycene [4–6], an interesting class of compound with a unique propeller-like threedimensional (3D) rigid structure, was found to be a useful building block for the construction of supramolecular systems with unique structures and properties; it can act not only as a spacer and a cavity-forming unit but also as a potential donor for p-stacking interactions. We have achieved the synthesis and structure of a porous silver(I) coordination complex with tpty, [Ag3(tpty)3(ClO4)3](toluene) and its guest desorption and adsorption complexes [7,8], and subsequently we report in this work the synthesis and characterization of other two silver(I)–tpty coordination complexes. One is [Ag(tpty)(THF)2](ClO4) (1) with a one-dimensional chain structure. The other [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2), is constructed by g1/ g2-coordination modes of tpty to silver(I) which reversibly incorporate anionic guest molecules, similar to the complex [Ag3(tpty)3(ClO4)3](toluene)2 from our previous work [7].
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was transferred to a 7 mm diameter glass tube under argon and was layered with n-pentane as a diffusion solvent. The glass tube was sealed under argon and wrapped with aluminum foil. The filtrate was left standing at room temperature for two weeks. Colorless brick single crystals of 2 were obtained. Anal. Calc. for Ag6S6F18O24C86H56: C, 37.87; H, 2.11. Found: C, 38.17; H, 2.31%. Main IR bands (KBr, m/cm1): 3750(m), 2966(m), 2371(s), 2353(s), 2342(s), 1458(s), 1300(s), 1235(s), 1178(s), 1042(s), 1026(s), 797(m), 741(s), 646(s), 640(s), 625(s). 2.2. Crystallography
2. Experimental All manipulations were performed under an argon atmosphere using Schlenk techniques. Organic solvents were reagent grade, and were dried and distilled using standards methods before use. Triptycene, silver perchlorate and silver triflate were purchased from Aldrich, all other chemicals were purchased from Wako Pure Chemical Co., Japan, and were used as receive without further purification. IR spectra were measured as KBr disks on a JASCO FT/IR-8000 spectrometer. TG analysis was performed on a Rigaku Thermo Plus TG 8120 spectrometer at 20 C/min and under argon. All crystallizations of the silver complexes were performed in the dark. Safety note: Perchlorate salts with organic ligands are potentially explosive! Only small amounts of materials should be prepared and they should be handled with great care. 2.1. Synthesis 2.1.1. [Ag(tpty)(THF)2](ClO4) (1) A solution of AgClO4 Æ H2O (19.1 mg, 0.08 mmol) in 5 ml of THF was added to triptycene (10.2 mg, 0.04 mmol). After 20 min of stirring, the resultant colorless solution was filtered. The filtrate was introduced into a narrow-diameter glass tube and carefully layered with 2 ml of n-pentane as a diffusion solvent. The glass tube was sealed under Ar and wrapped with aluminum foil. The filtrate was allowed to stand at room temperature for two weeks, upon which colorless platelet crystals of 1 were obtained. Anal. Calc. for AgClO6C28H30: C, 55.46; H, 4.95. Found: C, 55.75; H, 5.21%. Main IR bands (KBr, m/cm1): 2969(w), 1456(s), 1144(s), 1111(s), 1086(s), 797(m), 741(s), 627(s). 2.1.2. [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) A solution of Ag(CF3SO3) Æ H2O (27.1 mg, 0.1 mmol) in toluene (5.0 ml) was added to tpty (12.7 mg, 0.05 mmol). The mixture was stirred at room temperature for 20 min, and the resultant colorless solution was filtered. The filtrate
Diffraction data for 1 were collected at a temperature of 73 ± 1 C on a Quantum CCD area detector coupled with a Rigaku AFC8 diffractometer, and for 2 on a Rigaku AFC7 diffractometer with graphite-monochromated Mo ˚ ) at a temperature of 23.0. Ka radiation (k = 0.71069 A Intensity data were collected by using standard scan techniques (x–2h) to a maximum 2h value of 55.2 for 1 and 55.7 for 2. All intensity data were corrected for Lorentz and polarization effects. The structures were solved by direct methods (SIR-88 [9] for 1 and SIR-97 [10] for 2) and expanded using Fourier techniques [11]. All non-H atoms were refined with anisotropic thermal parameters. The final cycle of full-matrix least-squares refinements [12] for all the structures were performed on these data having I > 2r(I) and included anisotropic thermal parameters for non-hydrogen atoms. P P Reliability factors are defined as R = iFoj jFci/ jFoj P P 2 2 1=2 and Rw ¼ ½ wðF 2o F 2c Þ = wðF 2o Þ . All crystallographic computations were performed using the teXsan
Table 1 Crystallographic data for complexes 1 and 2 Complex
1
Formula AgClO6C28H30 Formula weight 605.86 Crystal system orthorhombic Space group Pbca (no. 61) ˚) a (A 15.168(3) ˚) b (A 16.2911(9) ˚) c (A 20.753(2) a () b () c () ˚ 3) V (A 5128(1) Z 8 F(000) 2480.00 T (C) 73.0 Dcalc (g/cm3) 1.569 ˚) k (Mo Ka) (A 0.71069 l (cm1) 9.30 Number of observed reflections 4824 Number of variable parameters 326 Residuals: Ra, Rwb 0.053, 0.155 Goodness-of-fit 1.05 P P a R = iFoj jFci/ jFoj. P P b 2 Rw ¼ ½ wðF o F 2c Þ2 = wðF 2o Þ2 1=2 .
2 Ag6S6F18O24C86H68 2666.98 monoclinic P21 (no. 4) 14.122(2) 16.180(2) 20.037(3) 90.00 90.350(15) 90.00 4578.4(12) 2 2632.00 23.0 2.006 0.71073 15.65 16 783 1261 0.0664, 0.1581 1.077
M. Wen et al. / Polyhedron 26 (2007) 2455–2460
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Table 2 ˚ ) and bond angles () for complexes 1 and 2 Selected bond distances (A Complex 1 Bond distances (A˚) Ag(1)–O(5) Ag(1)–C(17) Bond angles () O(5)–Ag(1)–O(6) O(6)–Ag(1)–C(5) Complex 2 Bond distances (A˚) Ag(1)–O(1) Ag(1)–O(6) Ag(2)–O(6) Ag(2)–C(79) Ag(3)–C(42) Ag(4)–C(62) Ag(4)–C(32) Ag(5)–O(11) Ag(6)–C(12) C(2)–C(7) Bond angles () O(5)–Ag(1)–O(4) O(5)–Ag(1)–O(1) C(39)–Ag(2)–O(6) C(39)–Ag(2)–C(2) C(39)–Ag(2)–C(7) C(2)–Ag(2)–C(7) C(79)–Ag(2)–C(78) C(42)–Ag(3)–O(2) C(42)–Ag(3)–C(19) C(32)–Ag(4)–C(62) C(32)–Ag(4)–O(7) C(32)–Ag(4)–C(63) O(7)–Ag(4)–C(63) O(11)–Ag(5)–O(9) O(9)–Ag(5)–O(12) O(52)–Ag(6)–C(72) C(72)–Ag(6)–C(12)
2.357(3) 2.392(4) 106.2(1) 98.1(1)
2.502(6) 2.481(6) 2.444(6) 2.454(9) 2.446(8) 2.445(9) 2.437(8) 2.360(6) 2.550 (9) 1.426(1) 120.0(2) 139.2(2) 102.3(2) 116.0(2) 109.9(2) 31.8(3) 30.4(3) 96.3(2) 124.7(2) 117.5(3) 100.1(2) 108.2(2) 114.0(2) 89.0(2) 87.1(2) 113.3(2) 121.3(2)
Ag(1)–O(6)
O(5)–Ag(1)–C(5) O(6)–Ag(1)–C(17)
Ag(1)–O(4) Ag(2)–C(2) Ag(2)–C(39) Ag(3)–C(19) Ag(3)–O(2) Ag(4)–C(63) Ag(5)–O(9) Ag(5)–O(12) Ag(6)–C(52) C(62)–C(63) O(5)–Ag(1)–O(6) O(4)–Ag(1)–O(1) C(39)–Ag(2)–C(79) O(6)–Ag(2)–C(2) O(6)–Ag(2)–C(7) C(39)–Ag(2)–C(78) C(2)–Ag(2)–C(78) C(42)–Ag(3)–C(22) O(2)–Ag(3)–C(19) C(32)–Ag(4)–C(58) C(62)–Ag(4)–O(7) C(62)–Ag(4)–C(63) O(10)–Ag(5)–O(11) O(10)–Ag(5)–O(12) O(12)–Ag(6)–C(52) O(12)–Ag(6)–C(12)
package [13]. Details of the X-ray experiments and crystal data are summarized in Table 1. Selected bond lengths and angles for the three complexes are given in Table 2. 3. Results and discussion In order to probe the influence of the ligand stereochemical preference with different anions on the coordination of a porous complex of silver(I), the study was carried out with the ligand tpty and the perchlorate and triflate counter anions. While single crystals of 1 show a 1D chain structure using ClO4 anions; when CF3 SO3 is employed as the counter anion, complex 2 gives a 3D porous structure with a cavity including guest molecules by using THF as the solvent. The IR spectra of the two complexes exhibit bands that can be readily assigned to ClO4 with strong bands at 1144, 1111 and 1086 cm1 for 1, and to CF3 SO3 with strong bands at 1235, 1178 and 1042 cm1 for 2. Compared to the criteria for non-coordination of ClO4 , with strong non-split broad bands at 1140, 1109 and 1087 cm1, and
2.299(3)
92.7(1) 122.0(1)
2.346(5) 2.511(8) 2.437(7) 2.570(9) 2.446(6) 2.659(9) 2.473(6) 2.498(5) 2.489(9) 1.355(8) 120.3(2) 88.9(2) 119.8(2) 82.8(2) 114.4(2) 110.2(2) 118.4(2) 117.6(2) 97.2(2) 125.4(3) 83.6(2) 30.4(2) 126.5(2) 116.8(2) 87.3(2) 92.2(2)
Ag(1)–C(5)
O(5)–Ag(1)–C(17) C(5)–Ag(1)–C(17)
Ag(1)–O(5) Ag(2)–C(7) Ag(2)–C(78) Ag(3)–C(22) Ag(4)–C(58) Ag(4)–O(7) Ag(5)–O(10) Ag(6)–O(12) Ag(6)–C(72) C(78)–C(79) O(4)–Ag(1)–O(6) O(6)–Ag(1)–O(1) O(6)–Ag(2)–C(79) C(79)–Ag(2)–C(2) C(79)–Ag(2)–C(7) O(6)–Ag(2)–C(78) C(7)–Ag(2)–C(78) O(2)–Ag(3)–C(19) C(22)–Ag(3)–C(19) C(62)–Ag(4)–C(58) C(58)–Ag(4)–O(7) C(58)–Ag(4)–C(63) O(10)–Ag(5)–O(9) O(11)–Ag(5)–O(12) O(12)–Ag(6)–C(72) C(52)–Ag(6)–C(12)
2.498(4)
107.6(2) 125.5(1)
2.299(7) 2.662(9) 2.679(9) 2.500(8) 2.483(8) 2.526(6) 2.321(6) 2.436(5) 2.498(9) 1.363(1) 89.9(2) 84.7(2) 94.2(2) 123.4(2) 114.6(2) 124.4(2) 95.4(2) 124.7(2) 116.3(3) 115.4(3) 98.2(2) 110.2(2) 133.7(2) 91.1(2) 97.9(2) 124.9(2)
CF3 SO3 , with strong non-split broad bands at 1256, 1179 and 1036 cm1, it indicates that ClO4 and CF3 SO3 are present not as ionic species, but as coordinated ones. The two complexes exhibit a strong m(C–C) absorption at 1456 cm1 as expected for the presence of tpty. 3.1. 1D chain of [Ag(tpty)(THF)2](ClO4) (1) The crystallographic studies reveal that complex 1 consists of a one-dimensional chain of [Ag(tpty)(THF)2] units, in which the crystallographically independent metal ions are bridged by triptycene. The structure of the trimeric molecular unit of the crystals is shown in Fig. 1a with the atomic numbering scheme employed. The Ag(1) ion has a tetrahedral coordination geometry, coordinated to two aromatic carbon atoms with Ag–C bond distances of ˚ , and two THF groups at Ag–O dis2.392(4) and 2.498(4) A ˚ , Table 2. One crystallotances of 2.357(3) and 2.299(3) A graphically independent ligand bridges the silver(I) atoms in a l–g1–g1 mode and gives a 1D chain in which the
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Fig. 1. (a) 1D chain structure of the complex [Ag(tpty)(THF)2](ClO4) (1). (b) Molecular packing of complex 1.
Fig. 2. TG curve of [Ag(tpty)(THF)2](ClO4) (1).
perchlorate groups occupy the space between the chains, Fig. 1b. From the TG analysis results of complex 1 (Fig. 2), the weight loss of 22.5% at 70 C indicates the severing of the two THF molecules (calculated value: 23.8%) which coordinated to Ag(I). 3.2. 3D porous structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) Complex 2 consists of a 2D sheet of [Ag6(tpty)4(CF3SO3)2(H2O)6] units (shown in Fig. 3), in which the six crystallographically independent metal ions are bridged by ligands and oxygen atoms. Ag(1) and Ag(5) are coordinated to three hydrate oxygen atoms and one triflate oxygen atom. Ag(2) is coordinated to three tpty moleculars in a g2/g1-mode and one triflate oxygen atom. Ag(3) and
Fig. 3. Molecular structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2).
Ag(6) are coordinated to three tpty moleculars in a g1coordination mode and one hydrate oxygen. Interestingly, Ag(4) is coordinated to two tpty moleculars in a g1-coordination mode, one tpty in a g2-mode and one triflate oxygen. So the Ag(I) ions are all four-coordinated and have a tetrahedral coordination geometry. The Ag–O bond dis˚ for Ag(1), 2.444(6) A ˚ tances are from 2.249(7) to 2.502(6) A ˚ ˚ for Ag(2), 2.446(6) A for Ag(3), 2.526(6) A for Ag(4), from ˚ for Ag(5) and 2.436(5) A ˚ for Ag(6), 2.321(6) to 2.498(5) A whereas Ag–C bond distance range from 2.437(7) to ˚ for Ag(2), from 2.446(8) to 2.570(9) A ˚ for 2.679(9) A ˚ Ag(3), from 2.437(8) to 2.483(8) A for Ag(4) and from ˚ for Ag(6), Table 2. Because of the 2.489(9) to 2.550(9) A rigid triangular molecule of tpty, the Ag–O bond distances do not show any significant variations in this complex. The molecule also contains four crystallographically independent ligands with distinctly different coordination modes, two with a l–g1–g1–g1 fashion bridging Ag(2), Ag(3), Ag(4) and Ag(6) ions, and the other two involve l–g1–g1–g2 and l–g1–g2–g2 fashions bridging four silver centers. A 2D sheet is thus formed in which the ligands are arranged alternately such that twofold in two lines up in one direction and the next four stand in the same direction (Fig. 4a). The two adjacent sheets are connected by a bridging triflate group and one hydrate linking Ag(1) or Ag(5) with Ag(2) and Ag(3) or Ag(4) and Ag(6), leading to a 3D porous polymer (Figs. 4b and 5a) with a cavity size ˚ and 5.0 · 4.3 A ˚ (Fig. 5b). In addition, caviof 5.0 · 4.8 A ties are occupied by triflate anions. So there are two types of triflate group: one is used as a bridging group and the other exists in a cavity. The cavity is difficult to use owing to the triflate anions, but not to neutral small solvent mol-
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Fig. 4. (a) 2D sheet of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2). (b) 3D structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2).
Fig. 5. (a) Space filling model of complex 2. (b) Space filling model of CF3 SO3 excluded from complex 2.
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having three equivalent benzene rings mutually inclined at 120. Prior to the present work, some X-ray crystal structures of triptycene p complexes have been reported, such as [Cr(tpty)(CO)3] [14], [Co4(tpty)(CO)9] [14], [SnCl(tpty)(AlCl4)]2 [15], [Cr2(tpty)CO]6 [16] and [(Cp*Ru)3(tpty)](CF3SO3)3 [17]. Fig. 6 cites instances of illustrations of the coordination mode from these complexes and the present complexes. For smaller metal atoms, it tends to interact with one metal atom by one arene ring in type (a) with a small widening of the inter-arene angles [14,17], such as [Cr(tpty)(CO)3], [Co4(tpty)(CO)9] and [(Cp*Ru)3(tpty)](CF3SO3)3, while with the larger metal atom tin it offers bis(arene) coordination with type (b) in [SnCl(tpty)(AlCl4)]2, sandwiching the cation, with the angle between the two arene rings contracted to 108.2 and the remaining inter-arene angles widened accordingly to 125.8 and 126.0 [15]. In addition, type (c) also exist in [(Cp*Ru)3(tpty)](CF3SO3)3 with the coordination of three tpty arene rings with the metal atoms. Triptycene in these complexes exhibits only a g6-mode by one to three benzene rings, the g1-mode and g2-mode are never observed. In the present Ag(I) coordination complexes with triptycene, [Ag(tpty)(THF)2](ClO4) (1), [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) and [Ag3(tpty)3(ClO4)3](toluene)2 [7], tpty exhibits an unprecedented g1-and g2-fashion bridging two or three Ag atoms, by (d) type in [Ag(tpty)(THF)2](ClO4), by (c) type in [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4, and by (c) and (d) coordination type in [Ag3(tpty)3(ClO4)3](toluene)2 [7], affording novel polymeric materials. Surprisingly, the tpty framework was found to involve relatively little deformation as compared to the metal-free hydrocarbon and the variation of the three inter-arene angles (115.6–124.4) is relatively small regardless of bis- or tris(arene) coordination. Such an eased conformation of the aromatic may in part be the contributing factor for the stable three-dimensional complex network formed and the relatively similar Ag–O bond distances observed. 4. Conclusion
Fig. 6. Coordination modes of triptycene complexes.
ecules located at cavities in which the triflate guests desorption does not occur on heating. This is dissimilar to silver(I) coordination complexes [Ag3(tpty)3(ClO4)3](toluene)2 in our previous work [7,8]. 3.3. Coordination types of tpty with metal ions The triangular molecule triptycene is a very special hydrocarbon with a relatively rigid molecular geometry,
In this paper, two silver(I)–tpty complexes have been synthesized and characterized by single-crystal X-ray determination, IR, TG analysis and element analysis. In two silver(I)–tpty complexes, the structure of the silver(I) coordination polymer is closely related to the ligand geometry and coordination site as well as coordination direction. In addition, the anion and solvent also play an important role in the construction of the complexes. In the tpty/ AgClO4/THF system, silver(I) ions are bridged by tpty and give rise to a 1D chain coordination complex [Ag(tpty)(THF)2](ClO4) (1). In addition, the solvent THF is coordinated to the silver(I) ions. Using a larger size anion, CF3 SO3 instead of ClO4 , a 3D porous complex [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2), with large cavities, ˚ and 5.0 · 4.3 A ˚ , has been with a size of 5.0 · 4.8 A obtained in toluene solvent. Although CF3 SO3 is included
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in the cavity, it is impossible to desorption and incorporate triflate molecules. Acknowledgements This work was partially supported by a Grants-inAid for Science Research [Nos. 10440201, 11874092, 12440189, 10016743 (priority area: metal-assembled complexes)] from the Ministry of Education, Science, Culture, Sports of Japan, and the Project-sponsored by SRF for ROCS from the SEM [No. 1380241005], EYT funds [No. 1380219055] from Tongji University of China. Appendix A. Supplementary material CCDC 220692 and 610349 contain the supplementary crystallographic data for this paper. 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: deposit@ ccdc.cam.ac.uk. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.poly.2006.12.036. References [1] M. Munakata, L.P. Wu, G.L. Ning, Coord. Chem. Rev. 198 (2000) 171.
[2] V. Gama, R.T. Henriques, M. Almeida, L. Veiros, M.J. Calhorda, A. Meetsma, J.L. de Boer, Inorg. Chem. 32 (1993) 3705. [3] L.P. Battaglia, C. Bellitto, M.R. Cramarossa, I.M. Vezzosi, Inorg. Chem. 35 (1996) 2390. [4] J.C. Ma, D.A. Dougherty, Chem. Rev. 97 (1997) 1303. [5] P.T. Corbett, L.H. Tong, J.K.M. Sanders, S. Otto, J. Am. Chem. Soc. 127 (2005) 8902. [6] X.Z. Zhu, C.F. Chen, J. Am. Chem. Soc. 127 (2005) 13158. [7] M. Munakata, L.P. Wu, K. Sugimoto, T. Kuroda-Sowa, M. Maekawa, Y. Suenaga, N. Maeno, M. Fujita, Inorg. Chem. 38 (1999) 5674. [8] M. Wen, M. Munakata, Y. Suenaga, T. Kuroda-Sowa, M. Maekawa, Inorg. Chim. Acta 340 (2002) 8. [9] M.C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo, G. Polidori, R. Spagna, D. Viterbo SIR-88, J. Appl. Crystallogr. 22 (1989) 389. [10] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C. Giacovazzo, A. Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna SIR97, J. Appl. Crystallogr. 32 (1999) 115. [11] P.T. Beurskens, G. Admiraal, G. Beurskens, W.P. Bosman, R. de Gelder, R. Israel, J.M.M. Smits, DIRDIF-94: The DIRDIF-94 Program System, Technical Report of the Crystallography Laboratory, University of Nijmegen, The Netherlands, 1994. [12] G.M. Sheldrick, SHELXL-97: Program for the Refinement of Crystal Structures, University of Go¨ettingen, Go¨ettingen, Germany, 1997. [13] teXsan: Crystal Structure Analysis Package, Molecular Structure Corporation, 1985 and 1999. [14] R.A. Gancarz, J.F. Blount, K. Mislow, Organometallics 4 (1985) 2028. [15] H. Schmidbaur, T. Probst, O. Steigelmann, Organometallics 10 (1991) 3176. [16] S. Toyata, H. Okuhara, M. Oki, Organometallics 16 (1997) 4012. [17] P.J. Fagan, M.D. Ward, J.C. Calabrese, J. Am. Chem. Soc. 111 (1989) 1698.
1D Chain and 3D framework of silver(I) organo-metallic polymers self-assembled with triptycene Ming Wen a,*, Megumu Munakata b, Yi-Zhi Li c, Yusaku Suenaga b, Takayoshi Kuroda-Sowa b, Masahiko Maekawa d, Manabu Anahata b a Department of Chemistry, Tongji University, 1239# SiPing Road, Shanghai 200092, China Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, China d Research Institute for Science and Technology, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan b
c
Received 11 September 2006; accepted 12 December 2006 Available online 10 January 2007
Abstract For the purpose of investigating the coordination behavior of sterically congested alkenes and exploring the possibility of non-planar complexation in the polycyclic aromatic system for formation of extended polymeric networks, triptycene (tpty) has been studied with regard to its complexation with the silver(I) ion. The crystal structures of [Ag(tpty)(THF)2](ClO4) (1) and [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) have been determined by single-crystal X-ray diffraction. The polycyclic aromatic hydrocarbon triptycene is found to offer a potential site for complexation, which can be utilized to generate an interesting array of organo-metallic polymers with onedimensional (1D) chain and three-dimensional (3D) porous frameworks. 2007 Elsevier Ltd. All rights reserved. Keywords: Silver(I) complex; Triptycene; Porous complex
1. Introduction Silver p-complexes of polycyclic aromatic hydrocarbons exhibit stereochemical features of exceptional interest. Such examples are the conformational variability of silver-polycyclic aromatic complexes with a vast range of open frameworks and layered materials in which the ionic inorganic species is occluded within an organic framework [1]. Aside from the interest in these fascinating structures, the new hybrid organic–inorganic layered and chain materials have often shown unique donor–acceptor electronic properties due to the overall planarity of the organic molecules and the extended delocalized p-systems [2,3]. In an effort to establish strategies aimed at the design of solids with large pores and to obtain a consequence of known structures of non-planar aromatic species, we are *
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currently engaged in a detailed study of the coordination chemistry of triptycene (tpty). Triptycene [4–6], an interesting class of compound with a unique propeller-like threedimensional (3D) rigid structure, was found to be a useful building block for the construction of supramolecular systems with unique structures and properties; it can act not only as a spacer and a cavity-forming unit but also as a potential donor for p-stacking interactions. We have achieved the synthesis and structure of a porous silver(I) coordination complex with tpty, [Ag3(tpty)3(ClO4)3](toluene) and its guest desorption and adsorption complexes [7,8], and subsequently we report in this work the synthesis and characterization of other two silver(I)–tpty coordination complexes. One is [Ag(tpty)(THF)2](ClO4) (1) with a one-dimensional chain structure. The other [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2), is constructed by g1/ g2-coordination modes of tpty to silver(I) which reversibly incorporate anionic guest molecules, similar to the complex [Ag3(tpty)3(ClO4)3](toluene)2 from our previous work [7].
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was transferred to a 7 mm diameter glass tube under argon and was layered with n-pentane as a diffusion solvent. The glass tube was sealed under argon and wrapped with aluminum foil. The filtrate was left standing at room temperature for two weeks. Colorless brick single crystals of 2 were obtained. Anal. Calc. for Ag6S6F18O24C86H56: C, 37.87; H, 2.11. Found: C, 38.17; H, 2.31%. Main IR bands (KBr, m/cm1): 3750(m), 2966(m), 2371(s), 2353(s), 2342(s), 1458(s), 1300(s), 1235(s), 1178(s), 1042(s), 1026(s), 797(m), 741(s), 646(s), 640(s), 625(s). 2.2. Crystallography
2. Experimental All manipulations were performed under an argon atmosphere using Schlenk techniques. Organic solvents were reagent grade, and were dried and distilled using standards methods before use. Triptycene, silver perchlorate and silver triflate were purchased from Aldrich, all other chemicals were purchased from Wako Pure Chemical Co., Japan, and were used as receive without further purification. IR spectra were measured as KBr disks on a JASCO FT/IR-8000 spectrometer. TG analysis was performed on a Rigaku Thermo Plus TG 8120 spectrometer at 20 C/min and under argon. All crystallizations of the silver complexes were performed in the dark. Safety note: Perchlorate salts with organic ligands are potentially explosive! Only small amounts of materials should be prepared and they should be handled with great care. 2.1. Synthesis 2.1.1. [Ag(tpty)(THF)2](ClO4) (1) A solution of AgClO4 Æ H2O (19.1 mg, 0.08 mmol) in 5 ml of THF was added to triptycene (10.2 mg, 0.04 mmol). After 20 min of stirring, the resultant colorless solution was filtered. The filtrate was introduced into a narrow-diameter glass tube and carefully layered with 2 ml of n-pentane as a diffusion solvent. The glass tube was sealed under Ar and wrapped with aluminum foil. The filtrate was allowed to stand at room temperature for two weeks, upon which colorless platelet crystals of 1 were obtained. Anal. Calc. for AgClO6C28H30: C, 55.46; H, 4.95. Found: C, 55.75; H, 5.21%. Main IR bands (KBr, m/cm1): 2969(w), 1456(s), 1144(s), 1111(s), 1086(s), 797(m), 741(s), 627(s). 2.1.2. [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) A solution of Ag(CF3SO3) Æ H2O (27.1 mg, 0.1 mmol) in toluene (5.0 ml) was added to tpty (12.7 mg, 0.05 mmol). The mixture was stirred at room temperature for 20 min, and the resultant colorless solution was filtered. The filtrate
Diffraction data for 1 were collected at a temperature of 73 ± 1 C on a Quantum CCD area detector coupled with a Rigaku AFC8 diffractometer, and for 2 on a Rigaku AFC7 diffractometer with graphite-monochromated Mo ˚ ) at a temperature of 23.0. Ka radiation (k = 0.71069 A Intensity data were collected by using standard scan techniques (x–2h) to a maximum 2h value of 55.2 for 1 and 55.7 for 2. All intensity data were corrected for Lorentz and polarization effects. The structures were solved by direct methods (SIR-88 [9] for 1 and SIR-97 [10] for 2) and expanded using Fourier techniques [11]. All non-H atoms were refined with anisotropic thermal parameters. The final cycle of full-matrix least-squares refinements [12] for all the structures were performed on these data having I > 2r(I) and included anisotropic thermal parameters for non-hydrogen atoms. P P Reliability factors are defined as R = iFoj jFci/ jFoj P P 2 2 1=2 and Rw ¼ ½ wðF 2o F 2c Þ = wðF 2o Þ . All crystallographic computations were performed using the teXsan
Table 1 Crystallographic data for complexes 1 and 2 Complex
1
Formula AgClO6C28H30 Formula weight 605.86 Crystal system orthorhombic Space group Pbca (no. 61) ˚) a (A 15.168(3) ˚) b (A 16.2911(9) ˚) c (A 20.753(2) a () b () c () ˚ 3) V (A 5128(1) Z 8 F(000) 2480.00 T (C) 73.0 Dcalc (g/cm3) 1.569 ˚) k (Mo Ka) (A 0.71069 l (cm1) 9.30 Number of observed reflections 4824 Number of variable parameters 326 Residuals: Ra, Rwb 0.053, 0.155 Goodness-of-fit 1.05 P P a R = iFoj jFci/ jFoj. P P b 2 Rw ¼ ½ wðF o F 2c Þ2 = wðF 2o Þ2 1=2 .
2 Ag6S6F18O24C86H68 2666.98 monoclinic P21 (no. 4) 14.122(2) 16.180(2) 20.037(3) 90.00 90.350(15) 90.00 4578.4(12) 2 2632.00 23.0 2.006 0.71073 15.65 16 783 1261 0.0664, 0.1581 1.077
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Table 2 ˚ ) and bond angles () for complexes 1 and 2 Selected bond distances (A Complex 1 Bond distances (A˚) Ag(1)–O(5) Ag(1)–C(17) Bond angles () O(5)–Ag(1)–O(6) O(6)–Ag(1)–C(5) Complex 2 Bond distances (A˚) Ag(1)–O(1) Ag(1)–O(6) Ag(2)–O(6) Ag(2)–C(79) Ag(3)–C(42) Ag(4)–C(62) Ag(4)–C(32) Ag(5)–O(11) Ag(6)–C(12) C(2)–C(7) Bond angles () O(5)–Ag(1)–O(4) O(5)–Ag(1)–O(1) C(39)–Ag(2)–O(6) C(39)–Ag(2)–C(2) C(39)–Ag(2)–C(7) C(2)–Ag(2)–C(7) C(79)–Ag(2)–C(78) C(42)–Ag(3)–O(2) C(42)–Ag(3)–C(19) C(32)–Ag(4)–C(62) C(32)–Ag(4)–O(7) C(32)–Ag(4)–C(63) O(7)–Ag(4)–C(63) O(11)–Ag(5)–O(9) O(9)–Ag(5)–O(12) O(52)–Ag(6)–C(72) C(72)–Ag(6)–C(12)
2.357(3) 2.392(4) 106.2(1) 98.1(1)
2.502(6) 2.481(6) 2.444(6) 2.454(9) 2.446(8) 2.445(9) 2.437(8) 2.360(6) 2.550 (9) 1.426(1) 120.0(2) 139.2(2) 102.3(2) 116.0(2) 109.9(2) 31.8(3) 30.4(3) 96.3(2) 124.7(2) 117.5(3) 100.1(2) 108.2(2) 114.0(2) 89.0(2) 87.1(2) 113.3(2) 121.3(2)
Ag(1)–O(6)
O(5)–Ag(1)–C(5) O(6)–Ag(1)–C(17)
Ag(1)–O(4) Ag(2)–C(2) Ag(2)–C(39) Ag(3)–C(19) Ag(3)–O(2) Ag(4)–C(63) Ag(5)–O(9) Ag(5)–O(12) Ag(6)–C(52) C(62)–C(63) O(5)–Ag(1)–O(6) O(4)–Ag(1)–O(1) C(39)–Ag(2)–C(79) O(6)–Ag(2)–C(2) O(6)–Ag(2)–C(7) C(39)–Ag(2)–C(78) C(2)–Ag(2)–C(78) C(42)–Ag(3)–C(22) O(2)–Ag(3)–C(19) C(32)–Ag(4)–C(58) C(62)–Ag(4)–O(7) C(62)–Ag(4)–C(63) O(10)–Ag(5)–O(11) O(10)–Ag(5)–O(12) O(12)–Ag(6)–C(52) O(12)–Ag(6)–C(12)
package [13]. Details of the X-ray experiments and crystal data are summarized in Table 1. Selected bond lengths and angles for the three complexes are given in Table 2. 3. Results and discussion In order to probe the influence of the ligand stereochemical preference with different anions on the coordination of a porous complex of silver(I), the study was carried out with the ligand tpty and the perchlorate and triflate counter anions. While single crystals of 1 show a 1D chain structure using ClO4 anions; when CF3 SO3 is employed as the counter anion, complex 2 gives a 3D porous structure with a cavity including guest molecules by using THF as the solvent. The IR spectra of the two complexes exhibit bands that can be readily assigned to ClO4 with strong bands at 1144, 1111 and 1086 cm1 for 1, and to CF3 SO3 with strong bands at 1235, 1178 and 1042 cm1 for 2. Compared to the criteria for non-coordination of ClO4 , with strong non-split broad bands at 1140, 1109 and 1087 cm1, and
2.299(3)
92.7(1) 122.0(1)
2.346(5) 2.511(8) 2.437(7) 2.570(9) 2.446(6) 2.659(9) 2.473(6) 2.498(5) 2.489(9) 1.355(8) 120.3(2) 88.9(2) 119.8(2) 82.8(2) 114.4(2) 110.2(2) 118.4(2) 117.6(2) 97.2(2) 125.4(3) 83.6(2) 30.4(2) 126.5(2) 116.8(2) 87.3(2) 92.2(2)
Ag(1)–C(5)
O(5)–Ag(1)–C(17) C(5)–Ag(1)–C(17)
Ag(1)–O(5) Ag(2)–C(7) Ag(2)–C(78) Ag(3)–C(22) Ag(4)–C(58) Ag(4)–O(7) Ag(5)–O(10) Ag(6)–O(12) Ag(6)–C(72) C(78)–C(79) O(4)–Ag(1)–O(6) O(6)–Ag(1)–O(1) O(6)–Ag(2)–C(79) C(79)–Ag(2)–C(2) C(79)–Ag(2)–C(7) O(6)–Ag(2)–C(78) C(7)–Ag(2)–C(78) O(2)–Ag(3)–C(19) C(22)–Ag(3)–C(19) C(62)–Ag(4)–C(58) C(58)–Ag(4)–O(7) C(58)–Ag(4)–C(63) O(10)–Ag(5)–O(9) O(11)–Ag(5)–O(12) O(12)–Ag(6)–C(72) C(52)–Ag(6)–C(12)
2.498(4)
107.6(2) 125.5(1)
2.299(7) 2.662(9) 2.679(9) 2.500(8) 2.483(8) 2.526(6) 2.321(6) 2.436(5) 2.498(9) 1.363(1) 89.9(2) 84.7(2) 94.2(2) 123.4(2) 114.6(2) 124.4(2) 95.4(2) 124.7(2) 116.3(3) 115.4(3) 98.2(2) 110.2(2) 133.7(2) 91.1(2) 97.9(2) 124.9(2)
CF3 SO3 , with strong non-split broad bands at 1256, 1179 and 1036 cm1, it indicates that ClO4 and CF3 SO3 are present not as ionic species, but as coordinated ones. The two complexes exhibit a strong m(C–C) absorption at 1456 cm1 as expected for the presence of tpty. 3.1. 1D chain of [Ag(tpty)(THF)2](ClO4) (1) The crystallographic studies reveal that complex 1 consists of a one-dimensional chain of [Ag(tpty)(THF)2] units, in which the crystallographically independent metal ions are bridged by triptycene. The structure of the trimeric molecular unit of the crystals is shown in Fig. 1a with the atomic numbering scheme employed. The Ag(1) ion has a tetrahedral coordination geometry, coordinated to two aromatic carbon atoms with Ag–C bond distances of ˚ , and two THF groups at Ag–O dis2.392(4) and 2.498(4) A ˚ , Table 2. One crystallotances of 2.357(3) and 2.299(3) A graphically independent ligand bridges the silver(I) atoms in a l–g1–g1 mode and gives a 1D chain in which the
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Fig. 1. (a) 1D chain structure of the complex [Ag(tpty)(THF)2](ClO4) (1). (b) Molecular packing of complex 1.
Fig. 2. TG curve of [Ag(tpty)(THF)2](ClO4) (1).
perchlorate groups occupy the space between the chains, Fig. 1b. From the TG analysis results of complex 1 (Fig. 2), the weight loss of 22.5% at 70 C indicates the severing of the two THF molecules (calculated value: 23.8%) which coordinated to Ag(I). 3.2. 3D porous structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) Complex 2 consists of a 2D sheet of [Ag6(tpty)4(CF3SO3)2(H2O)6] units (shown in Fig. 3), in which the six crystallographically independent metal ions are bridged by ligands and oxygen atoms. Ag(1) and Ag(5) are coordinated to three hydrate oxygen atoms and one triflate oxygen atom. Ag(2) is coordinated to three tpty moleculars in a g2/g1-mode and one triflate oxygen atom. Ag(3) and
Fig. 3. Molecular structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2).
Ag(6) are coordinated to three tpty moleculars in a g1coordination mode and one hydrate oxygen. Interestingly, Ag(4) is coordinated to two tpty moleculars in a g1-coordination mode, one tpty in a g2-mode and one triflate oxygen. So the Ag(I) ions are all four-coordinated and have a tetrahedral coordination geometry. The Ag–O bond dis˚ for Ag(1), 2.444(6) A ˚ tances are from 2.249(7) to 2.502(6) A ˚ ˚ for Ag(2), 2.446(6) A for Ag(3), 2.526(6) A for Ag(4), from ˚ for Ag(5) and 2.436(5) A ˚ for Ag(6), 2.321(6) to 2.498(5) A whereas Ag–C bond distance range from 2.437(7) to ˚ for Ag(2), from 2.446(8) to 2.570(9) A ˚ for 2.679(9) A ˚ Ag(3), from 2.437(8) to 2.483(8) A for Ag(4) and from ˚ for Ag(6), Table 2. Because of the 2.489(9) to 2.550(9) A rigid triangular molecule of tpty, the Ag–O bond distances do not show any significant variations in this complex. The molecule also contains four crystallographically independent ligands with distinctly different coordination modes, two with a l–g1–g1–g1 fashion bridging Ag(2), Ag(3), Ag(4) and Ag(6) ions, and the other two involve l–g1–g1–g2 and l–g1–g2–g2 fashions bridging four silver centers. A 2D sheet is thus formed in which the ligands are arranged alternately such that twofold in two lines up in one direction and the next four stand in the same direction (Fig. 4a). The two adjacent sheets are connected by a bridging triflate group and one hydrate linking Ag(1) or Ag(5) with Ag(2) and Ag(3) or Ag(4) and Ag(6), leading to a 3D porous polymer (Figs. 4b and 5a) with a cavity size ˚ and 5.0 · 4.3 A ˚ (Fig. 5b). In addition, caviof 5.0 · 4.8 A ties are occupied by triflate anions. So there are two types of triflate group: one is used as a bridging group and the other exists in a cavity. The cavity is difficult to use owing to the triflate anions, but not to neutral small solvent mol-
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Fig. 4. (a) 2D sheet of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2). (b) 3D structure of [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2).
Fig. 5. (a) Space filling model of complex 2. (b) Space filling model of CF3 SO3 excluded from complex 2.
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having three equivalent benzene rings mutually inclined at 120. Prior to the present work, some X-ray crystal structures of triptycene p complexes have been reported, such as [Cr(tpty)(CO)3] [14], [Co4(tpty)(CO)9] [14], [SnCl(tpty)(AlCl4)]2 [15], [Cr2(tpty)CO]6 [16] and [(Cp*Ru)3(tpty)](CF3SO3)3 [17]. Fig. 6 cites instances of illustrations of the coordination mode from these complexes and the present complexes. For smaller metal atoms, it tends to interact with one metal atom by one arene ring in type (a) with a small widening of the inter-arene angles [14,17], such as [Cr(tpty)(CO)3], [Co4(tpty)(CO)9] and [(Cp*Ru)3(tpty)](CF3SO3)3, while with the larger metal atom tin it offers bis(arene) coordination with type (b) in [SnCl(tpty)(AlCl4)]2, sandwiching the cation, with the angle between the two arene rings contracted to 108.2 and the remaining inter-arene angles widened accordingly to 125.8 and 126.0 [15]. In addition, type (c) also exist in [(Cp*Ru)3(tpty)](CF3SO3)3 with the coordination of three tpty arene rings with the metal atoms. Triptycene in these complexes exhibits only a g6-mode by one to three benzene rings, the g1-mode and g2-mode are never observed. In the present Ag(I) coordination complexes with triptycene, [Ag(tpty)(THF)2](ClO4) (1), [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) and [Ag3(tpty)3(ClO4)3](toluene)2 [7], tpty exhibits an unprecedented g1-and g2-fashion bridging two or three Ag atoms, by (d) type in [Ag(tpty)(THF)2](ClO4), by (c) type in [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4, and by (c) and (d) coordination type in [Ag3(tpty)3(ClO4)3](toluene)2 [7], affording novel polymeric materials. Surprisingly, the tpty framework was found to involve relatively little deformation as compared to the metal-free hydrocarbon and the variation of the three inter-arene angles (115.6–124.4) is relatively small regardless of bis- or tris(arene) coordination. Such an eased conformation of the aromatic may in part be the contributing factor for the stable three-dimensional complex network formed and the relatively similar Ag–O bond distances observed. 4. Conclusion
Fig. 6. Coordination modes of triptycene complexes.
ecules located at cavities in which the triflate guests desorption does not occur on heating. This is dissimilar to silver(I) coordination complexes [Ag3(tpty)3(ClO4)3](toluene)2 in our previous work [7,8]. 3.3. Coordination types of tpty with metal ions The triangular molecule triptycene is a very special hydrocarbon with a relatively rigid molecular geometry,
In this paper, two silver(I)–tpty complexes have been synthesized and characterized by single-crystal X-ray determination, IR, TG analysis and element analysis. In two silver(I)–tpty complexes, the structure of the silver(I) coordination polymer is closely related to the ligand geometry and coordination site as well as coordination direction. In addition, the anion and solvent also play an important role in the construction of the complexes. In the tpty/ AgClO4/THF system, silver(I) ions are bridged by tpty and give rise to a 1D chain coordination complex [Ag(tpty)(THF)2](ClO4) (1). In addition, the solvent THF is coordinated to the silver(I) ions. Using a larger size anion, CF3 SO3 instead of ClO4 , a 3D porous complex [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2), with large cavities, ˚ and 5.0 · 4.3 A ˚ , has been with a size of 5.0 · 4.8 A obtained in toluene solvent. Although CF3 SO3 is included
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in the cavity, it is impossible to desorption and incorporate triflate molecules. Acknowledgements This work was partially supported by a Grants-inAid for Science Research [Nos. 10440201, 11874092, 12440189, 10016743 (priority area: metal-assembled complexes)] from the Ministry of Education, Science, Culture, Sports of Japan, and the Project-sponsored by SRF for ROCS from the SEM [No. 1380241005], EYT funds [No. 1380219055] from Tongji University of China. Appendix A. Supplementary material CCDC 220692 and 610349 contain the supplementary crystallographic data for this paper. 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: deposit@ ccdc.cam.ac.uk. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.poly.2006.12.036. References [1] M. Munakata, L.P. Wu, G.L. Ning, Coord. Chem. Rev. 198 (2000) 171.
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