DOI: 10.1021/cg900814b
Assembly of Seven Supramolecular Compounds with p-Sulfonatocalix[6]arene
2009, Vol. 9 5311–5318
Yabing Liu, Wuping Liao,* Yanfeng Bi, Xiaofei Wang, and Hongjie Zhang* State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China Received July 16, 2009; Revised Manuscript Received September 27, 2009
ABSTRACT: Seven supramolecular compounds comprising p-sulfonatocalix[6]arene and transition metals, {[Cu(Imz)(phen)(H2O)]4[C6AS]} 3 10H2O (1), {[Cu(Imz)2(phen)]2[Cu(Imz)(phen)(H2O)2]2[C6AS]} 3 13.3H2O (2), {[M(phen)2(H2O)][M(phen)2]2[C6AS]} 3 nH2O (3 and 4) (3: M=Co and n=29.6; 4: M=Zn and n=29.9), {[Cu(phen)2]4[C6AS]}2 3 13H2O (5), [H3O]2[Co(phen)3]2[C6AS] 3 10.7H2O (6), and [Cu(phen)2(H2O)]2{[Cu(phen)2]2[C6AS]} 3 8H2O (7) (phen=1,10-phenanthroline, C6AS = p-sulfonatocalix[6]arene, Imz = imidazole), have been synthesized by a hydrothermal method and structurally characterized by IR spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA), and single crystal X-ray diffraction. It is found that not only the acidity of the feeds plays an important role in the syntheses, but also the kind of metals, the molar ratio of the reactants, and the cochelating ligands influence the final extended structures. The extended structures are featured with two-dimensional (2D) coordination layers, one-dimensional chains, or zero-dimensional fragments. Notedly, the 2D metal-C6AS coordination layer was observed for the compounds of p-sulfonatocalix[6]arene for the first time. In these structures, all the C6AS ligands adopt a 1,2,3-alternate conformation.
Introduction p-Sulfonatocalix[n]arenes (CnAS, n=4, 5, 6, or 8), a wellknown kind of water-soluble calixarene derivative, have been attracting increasing attention in supramolecular chemistry and coordination chemistry.1,2 Among them, p-sulfonatecalix[4]arenes (C4AS) has gained much attention, and a variety of structures composed of “Russian dolls”,3 “molecular capsules”,4 “ferris wheels”,5 hydrogen bonded polymers, and coordination polymers have been reported.6 In contrast to the flourishing study on C4AS, the solid-state supramolecular chemistry of the corresponding calix[5, 6, and 8]arenes is less well developed. For example, although p-sulfonatocalix[6]arenes (C6AS) possesses a profusion of active oxygen atoms from sulfonate and phenoxyl groups which might be helpful to coordinate various cationic units, it has not been used as a popular building block due to its flexible conformation and high charge. Raston and Atwood et al. reported some architectures in which C6AS can act as a ditopic receptor to specific guest molecules such as crown ether, pyridine N-oxide, 4,40 dipyridine-N,N0 -dioxide, lanthanide, transition metal and tetraphenylphosphonium cations to form extended supramolecular arrays and bimolecular capsules.7 Liu et al. prepared the inclusion compounds of C6AS with 1,10-phenanthroline (phen), 6,7-dihydro-5H-[1,4]diazepino-[1,2,3,4-lmn][1,10]phenanthroline-4,8-diium, protonated quinoline and 8-hydroxyquinoline guests.8 Long and co-workers reported a supramolecular complex assembling from the building blocks of C6AS and cucurbit[6]uril through noncovalent bonding.9 Recently, our group prepared a copper/C6AS/phen supramolecular compound with one-dimensional (1D) [Cu2calixarene]n coordination chains.10 However, as we know, the two- or three-dimensional (2D or 3D) coordination networks of C6AS were not reported. On the basis of our
previous work on the calixarenes,11 we extended our research to the C6AS-phen system. Here we present the syntheses and structures of seven novel compounds {[Cu(Imz)(phen)(H2O)]4[C6AS]} 3 10H2O (1), {[Cu(Imz)2(phen)]2[Cu(Imz)(phen) (H2O)2]2[C6AS]} 3 13.3H2O (2), {[M(phen)2(H2O)][M(phen)2]2 [C6AS]} 3 nH2O (3 and 4) (3: M=Co and n=29.6; 4: M=Zn and n=29.9) {[Cu(phen)2]4[C6AS]}2 3 13H2O (5), [H3O]2[Co(phen)3]2[C6AS] 3 10.7H2O (6), and [Cu(phen)2(H2O)]2{[Cu(phen)2]2[C6AS]} 3 8H2O (7) (phen = 1,10-phenanthroline, C6AS = p-sulfonatocalix[6]arene, Imz = imidazole). Among them, one can find a 2D metal-C6AS coordination network and some 1D metal-C6AS coordination chains. To the best of our knowledge, it is the first time the 2D coordination network for C6AS has been reported. Experimental Section
*Corresponding author. Tel: þ86-431-8526-2036; fax: þ86-431-85698041; e-mail:
[email protected] (W.P.L.),
[email protected] (H.J.Z.).
Materials and Measurement. The sodium salt of p-sulfonatocalix[6]arene was synthesized according to the literature method,12 and other reagents were purchased from commercial sources and used as received. The thermogravimetric analysis (TGA) was carried out on a Perkin-Elmer TGA-7000 instrument from 40 to 800 °C, with a heating rate of 10 °C min-1 under a nitrogen flow. FT-IR (KBr pellets) spectra were recorded in the range of 225-4000 cm-1 using a Perkin-Elmer Spectrum One FTIR spectrophotometer. Preparation of Compounds 1-7. [Cu(Imz)(phen)(H2O)]4[C6AS] 3 10H2O (1) and [Cu(Imz)2(phen)]2[Cu(Imz)(phen)(H2O)2]2 [C6AS] 3 13.3H2O (2). A suspension of CuCl2 3 2H2O (34.0 mg, 0.2 mmol), Na6C6AS (62.4 mg, 0.05 mmol), phen (39.6 mg, 0.2 mmol), and imidazole (34.0 mg, 0.5 mmol) in water (10 mL) was transferred into a Teflon-lined stainless-steel autoclave. The autoclave was heated to 130 °C in 90 min, kept at that temperature for 4 days, and then cooled gradually to room temperature at about 4 °C h-1. The final pH value of the solution was 6.6. Green block crystals of 1 and blue block crystals of 2 suitable for X-ray diffraction analysis were isolated. Yield: 28% for 1 and 10% for 2 with respect to C6AS. {[M(phen)2(H2O)][M(phen)2]2[C6AS]} 3 nH2O (3: M=Co and n= 29.6; 4: M=Zn and n=29.9). Orange block crystals of 3 and colorless block crystals of 4 were obtained by hydrothermal treating the
r 2009 American Chemical Society
Published on Web 10/13/2009
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Crystal Growth & Design, Vol. 9, No. 12, 2009
Liu et al.
Table 1. Crystallographic Data for Compounds 1-7 1
3
4
5
6
7
C138H169.06Co4 N16O55.53S6
C138H169.74Zn4 N16O55.87S6
C138H118Cu4 N16O37S6
C114H105.32Co2 N12O36.66S6
C138H112Cu4 N16O34S6
2608.53 186(2)
C108H118.50 Cu4 N20O41.25S6 2803.25 187(2)
3039.00 187(2)
2540.20 173(2)
13.3935(5) 14.9472(5) 15.8144(6) 67.904(1) 69.399(1) 66.590 (1) 2614.6(2) 1 1.654 1.021 1344 18978 9166 0.0324 1.066 0.0428 0.1217
12.8498(5) 13.3198(5) 17.2996(7) 82.762(1) 82.390(1) 84.626(1) 2902.5(2) 1 1.600 0.929 1442 17765 10165 0.0240 1.060 0.0409 0.1081
12.1344(5) 15.4172(6) 20.3397(7) 80.495(1) 85.236(1) 89.904(1) 3739.6(2) 1 1.490 0.616 1744 35910 13161 0.0363 1.078 0.0615 0.1863
16.0944(9) 16.1653(8) 26.696(2) 91.654(1) 105.849(1) 98.066(1) 6598.9(6) 2 1.529 0.821 3132 39928 23085 0.0311 1.021 0.0978 0.2481
11.2771(5) 15.4311(7) 16.2779(7) 85.799(1) 82.086(1) 75.895(1) 2718.8(2) 1 1.551 0.516 1317 14721 9521 0.0252 1.055 0.0437 0.1052
2984.96 187(2) monoclinic Ρ21/c 20.5525(7) 14.8671(5) 25.5502(7) 90 127.511(2) 90 6192.8(3) 2 1.601 0.872 3072 44011 10915 0.0497 1.088 0.0460 0.1484
formula
C102H104Cu4 N16O38S6
formula wt T (K) cryst. syst. space group a (A˚) b (A˚) c (A˚) R (deg) β (deg) γ (deg) volume (A˚3) Z Dc/g cm-3 μ/mm-1 F(000) total data unique data Rint GOF R1a [I > 2σ(I)] wR2b a
2
3368.51 187(2)
3400.40 186(2) triclinic Ρ1 12.1579(4) 15.4571(5) 20.2944(7) 99.640(1) 94.916(1) 90.071(1) 3745.7(2) 1 1.507 0.813 1773 22998 13158 0.0273 1.088 0.0594 0.1912
R1=Σ||Fo| - |Fc||/Σ|Fo|. b wR2={Σ[w(Fo2 - Fc2)2]/Σ[w(Fo2)2]}1/2.
Scheme 1. Syntheses of Compounds 1-7
suspension of CoCl2 3 6H2O (24 mg, 0.1 mmol) or ZnCl2 (13.6 mg, 0.1 mmol), Na6C6AS (62.4 mg, 0.05 mmol), and phen (39.6 mg, 0.2 mmol) in 10 mL of deionized water (whose pH value was adjusted by 0.4 mol/L triethylamine aqueous solution to 5.2) following similar procedures for the syntheses of 1 and 2. The final pH value was 4.8. Yield: 24% for 3 and 31% for 4. {[Cu(phen)2]4[C6AS]}2 3 13H2O (5). Green block crystals of 5 were obtained by similar experiments for the syntheses of 3 and 4 but with CoCl2 3 6H2O or ZnCl2 replaced by CuCl2 3 2H2O (17 mg, 0.1 mmol). The pH value of the feed was first adjusted to about 5 and the final pH value was 4.5. Yield: 23% for 5. [H3O]2[Co(phen)3]2[C6AS] 3 10.7H2O (6). The synthesis of 6 was similar to that of 3, but the pH value was adjusted using hydrochloric acid (1 mol/L) to 1.5 first. The final pH value of the solution was less than 1. Yield: 41% for 6. [Cu(phen)2(H2O)]2{[Cu(phen)2]2[C6AS]} 3 8H2O (7). Green block crystals of 7 were obtained by similar experiments for the syntheses of 3 and 4 but with CoCl2 3 6H2O or ZnCl2 replaced by CuCl2 3 2H2O (17 mg, 0.1 mmol). The pH value of the feed was first adjusted to about 4.5 and the final pH value was 3.8. Yield: 17% for 7. X-ray Crystal Structure Analysis. The X-ray intensity data for compounds 1-7 were collected on a Bruker SMART APEX CCD diffractometer with graphite-monochromatized Mo KR radiation (λ = 0.71073 A˚) operated at 2.0 kW (50 kV, 40 mA). The crystal structure was solved by means of Direct Methods and refined
Scheme 2. Coordinations of C6AS in Compounds 1-7: (a) 1; (b) 2-4; (c) 5; (d) 6; and (e) 7
employing full-matrix least-squares on F2 (SHELXTL Program).13 All non-hydrogen atoms except some disordered water molecules were refined anisotropically, and hydrogen atoms of the phen and C6AS were generated theoretically onto the specific atoms and refined isotropically with fixed thermal factors. The refinement details for these compounds are given in Table 1. Crystallographic data for these structures reported here have been deposited in Cambridge Crystallographic Data Center with CCDC reference numbers 733763-733768 and 737591 for compounds 1-7.
Results and Discussion Syntheses. Compounds 1-7 were prepared under similar hydrothermal conditions, and their formations were governed by the reaction conditions such as the reactants, the
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Figure 1. Compound 1: (a) molecular structure (carbon atoms of phen ligands, water molecules and hydrogen atoms are omitted for clarity); (b) a ball-and-stick plot (left; phen and imidazole molecules are omitted for clarity) and the topological representation of the 2D coordination layer (right; C6AS: yellow; copper atoms: blue); (c) the stacking of the coordination layers through hydrogen bonds (green dotted lines) and π 3 3 3 π stacking interactions (black dotted lines); (d) topological representation of the extended structure (purple line, π 3 3 3 π stacking interactions).
molar ratio of the reactants, cochelating ligands, and the pH value of the reaction system. The synthesis conditions of compounds 1-7 are summarized in Scheme 1. As Atwood et al. reported,14 the pKa1-2 values for the phenolic hydroxyls of C6AS are 4.76 and 3.44, respectively. At a higher pH value, the phenolic hydroxyl groups should be deprotonated more easily and the coordination number of the C6AS ligand might become larger. The coordinations of C6AS in compounds 1-7 are shown in Scheme 2. It can be found that the metals bonded to C6AS become less in number with the increasing acidity of the feeds and even reach none when the pH value of the feed is below 1. The 2D networks or 1D chains formed when the pH value of the feed was higher than 4.5, while 0D fragments formed with the pH value being
