Formation and Crystal Structure of Two-Component Host System

Nov 24, 2008 - A two-component supramolecular host system having multiple chiral points (central, axial, and helical), which can include an n-alkyl al...
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Formation and Crystal Structure of Two-Component Host System Having Helical Chirality and Comprising 9,10-Dihydro-9,10-ethanoanthracene-11,12-diamine and 1,1′-Binaphthyl-2,2′-dicarboxylic Acid

CRYSTAL GROWTH & DESIGN 2009 VOL. 9, NO. 1 602–605

Yoshitane Imai,*,† Katuzo Murata,† Kensaku Kamon,† Takafumi Kinuta,† Tomohiro Sato,‡ Reiko Kuroda,‡,§ and Yoshio Matsubara*,† Department of Applied Chemistry, Faculty of Science and Engineering, Kinki UniVersity, 3-4-1 Kowakae, Higashi-Osaka, Osaka, 577-8502, Japan, JST ERATO-SORST Kuroda Chiromorphology Team, 4-7-6, Komaba, Meguro-ku, Tokyo, 153-0041, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The UniVersity of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan ReceiVed August 20, 2008; ReVised Manuscript ReceiVed September 29, 2008

ABSTRACT: A two-component supramolecular host system having multiple chiral points (central, axial, and helical), which can include an n-alkyl alcohol molecule, was successfully formed by combining (11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12diamine with central chirality and (S)-1,1′-binaphthyl-2,2′-dicarboxylic acid with axial chirality. The helical chirality of this host system was induced by the central and axial chiralities of the component molecules in solid state. Introduction Many supramolecular chiral organic host compounds used for chiral recognition and enantioselective reactions have been reported.1 In particular, chiral recognition by multiple chiral points is required in a host system in order to increase the chiral recognition ability for a guest molecule. Moreover, the demand for the modulation of the size and shape of the chiral cavity in a chiral host system has increased in order to accommodate various guest molecules. In order to satisfy these demands, supramolecular chiral organic host systems composed of two or three molecules have been developed.2 Recently, we have reported a two-component chiral supramolecular host system of achiral biphenic acid or chiral (R)-1,1′binaphthyl-2,2′-dicarboxylic acid combined with (1R,2R)-1,2diphenylethylenediamine or (1S,2S)-1,2-cyclohexanediamine.3 These chiral host systems have central, axial, and helical chiralities induced by the complexation of component molecules. Although it is generally difficult to carry out optical resolution of secondary alkyl alcohols with an OH group at the R-position, RCH(CH3)OH, due to the subtle structural difference between the enantiomers as the methyl group and hydrogen atom attached to the chiral carbon have to be discriminated, these chiral host systems with multiple chiral points can enantioselectively include secondary alkyl alcohols as guests. Moreover, by tuning the packing of two component molecules, various guest molecules can be accommodated into the chiral cavities of the host complex. One of the advantages of this supramolecular host system is that the shape and properties of the chiral cavity may be easily modified by changing the component molecules. Although previously used (1R,2R)-1,2-diphenylethylenediamine comprises two bulky substituents (phenyl group), it is extremely flexible. On the other hand, although the previously used (1S,2S)-1,2-cyclohexanediamine is comparatively rigid, it is not bulky. Therefore, a new type of chiral cavity may be formed if * To whom correspondence should be addressed. (Y.I.) Tel: +1-6-67305880(ext 5241). Fax: +81-6-6727-2024. E-mail: [email protected]. (Y.M.) E-mail: [email protected]. † Kinki University. ‡ JST. § The University of Tokyo.

a bulky and rigid diamine molecule is used as one of the component molecules. In this paper, we report the formation and crystal structure of a novel two-component supramolecular host system comprising chiral 1,1′-binaphthyl-2,2′-dicarboxylic acid (1) and having multiple chiral points (central, axial, and helical). For the bulky and rigid diamine portion, (11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-diamine [(11R,12R)-2] having a bulky and rigid backbone was used. Usually, it is difficult to predict the formation and crystal structure of supramolecular organic complexes for new component molecules. Therefore, an investigation of the structure of supramolecular complexes by using basic supramolecular building blocks has attracted considerable attention as a bottom-up approach for studying supramolecular host-guest chemistry. Thus, in order to study the guest inclusion mechanism of a new type of supramolecular complex by X-ray crystallographic analysis, three simple normal(n)-alkyl alcohols having different alkyl chains [methanol (MeOH), ethanol (EtOH), and n-propanol (n-PrOH)] are used as guest molecules.

Experimental Section General Methods. Component molecules (R)- and (S)-1 were provided by Mitsubishi Tanabe Pharma Corp. The component molecule (11R,12R)-2 was purchased from Tokyo Kasei Kogyo Co., Ltd. The guest solvent was purchased from Wako Pure Chemical Industries. Formation of Inclusion Complex by Crystallization from Solution. (R)-1 [or (S)-1] (20 mg, 0.058 mmol) and (11R,12R)-2 (15 mg, 0.063 mmol) were dissolved in each guest solution (3 mL). In the (S)-1/(11R,12R)-2 host system, after a week, colorless crystals I, II, and III were deposited and collected from MeOH, EtOH, and n-PrOH solutions, respectively. The total weight of all the crystals obtained in a batch was 8-12 mg. X-ray Crystallographic Study of Crystal I. X-ray diffraction data for single crystals were collected using BRUKER APEX. The crystal structures were solved by the direct method4 and refined by full-matrix

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Formation and Crystal Structure of Two-Component Host System

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least-squares using SHELX97.5 The diagrams were prepared using PLATON.6 Absorption corrections were performed using SADABS.7 Non-hydrogen atoms were refined with anisotropic displacement parameters, and hydrogen atoms were included in the models in their calculated positions in the riding model approximation. Crystallographic data of I: C22H12O4 · 2C16H17N2 · H2O · CH4O, M ) 865.01, orthorhombic, space group P212121, a ) 12.9012(10) Å, b ) 14.2134(12) Å, c ) 25.111(2) Å, U ) 4604.6(6) Å3, Z ) 4, Dc ) 1.248 g cm-3, µ(Mo KR) ) 0.082 mm-1, 28697 reflections measured, 10568 unique, final R(F2) ) 0.0619 using 9162 reflections with I > 2.0σ(I), R(all data) )0.0723, T ) 115(2) K, CCDC 697965. Crystallographic data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB21EZ, UK; fax: (+44)1223-336-033; [email protected]). X-ray Crystallographic Study of Crystal II. Crystallographic data of II: C22H12O4 · 2C16H17N2 · H2O · C2H6O, M ) 879.03, orthorhombic, space group P212121, a ) 12.9155(9) Å, b ) 14.2194(10) Å, c ) 25.2284(17) Å, U ) 4633.2(6) Å3, Z ) 4, Dc ) 1.260 g cm-3, µ(Mo KR) ) 0.082 mm-1, 28191 reflections measured, 10510 unique, final R(F2) ) 0.0639 using 8930 reflections with I > 2.0σ(I), R(all data) ) 0.0783, T ) 115(2)K, CCDC 697966. X-ray Crystallographic Study of Crystal III. Crystallographic data of III: C22H12O4 · 2C16H17N2 · H2O · C3H8O, M ) 893.06, orthorhombic, space group P212121, a ) 12.8177(8) Å, b ) 14.4717(9) Å, c ) 25.1811(15) Å, U ) 4670.9(5) Å3, Z ) 4, Dc ) 1.270 gcm-3, µ(Mo KR) ) 0.083 mm-1, 41511 reflections measured, 10755 unique, final R(F2) ) 0.0667 using 9066 reflections with I > 2.0σ(I), R(all data) ) 0.0818, T ) 115(2) K, CCDC 697967.

Results and Discussion First, the complexation behavior of the 1/(11R,12R)-2 host system was studied for the MeOH guest molecule. The formation of an inclusion complex was attempted by crystallization of the guest MeOH solution containing (R)-1 [or (S)-1] and (11R,12R)-2. As a result, differences in the complexation behavior were observed corresponding to the chiralities of 1 and 2. In the case of (R)-1 and (11R,12R)-2, an inclusion complex was not formed from the guest MeOH solution. However, in the case of (S)-1 and (11R,12R)-2, inclusion complex I was obtained by crystallization of the MeOH solution. In order to study the structure of this inclusion complex, X-ray crystallographic analysis of the obtained crystals was carried out. The crystal structure of complex I is shown in Figure 1. Complex I formed from (S)-1 (Figure 1, represented as blue molecules) and (11R,12R)-2 (Figure 1, represented as green molecules) includes MeOH molecules (Figure 1, represented as red and purple molecules) as guest molecules. The stoichiometry of complex I is (S)-1:(11R,12R)-2/H2O/MeOH ) 1:2: 1:1, and the space group is P212121. Characteristically, this complex has a helical columnar hydrogen- and ionic-bonded network around the 21-axis and along the a-axis (parts (a) and (b) of Figure 1). This network is formed mainly by the ammonium hydrogen of one protonated amine and the carboxylate oxygen of a carboxylic acid anion. The included water molecules (Figure 1, represented by red balls) that link the two carboxyl groups of (S)-1 through the hydrogen bonds and contribute to the maintenance of the column frame. Each helical column network interacts with other helical column networks through one type of naphthalene edge-to-face interaction (Figure 1d, indicated by red arrows, 2.65 Å). As a result, chiral cavities are formed by the self-assembly of this helical column (Figure 1d). Interestingly, these cavities have the axial chirality of 1, central chirality of 2, and helical chirality of the column network structure induced by complexation. In this chiral cavity, the MeOH guest molecule (Figure 1, represented as red molecules) is trapped with the included water molecules (represented by red balls) through a hydrogen bond. From the X-ray crystallographic analysis, an electron density corresponding to a small

Figure 1. Crystal structure of complex I. (S)-1, (11R,12R)-2, major MeOH, and minor MeOH molecules are represented as blue, green, red, and purple molecules, respectively. Water molecules are represented by red balls. (a) Helical columnar hydrogen- and ionic-bonded network parallel to the a-axis. (b) View down the a-axis. (c) Packing of the minor MeOH molecules observed along the a-axis. (d) Packing structure observed along the a-axis. Minor MeOH molecules are not shown. The red arrows indicate the naphthalene edge-to-face interactions.

amount of other MeOH molecules (Figure 1c, represented as purple molecules) having different packing from the major MeOH molecules (Figure 1b, represented as red molecules) is observed as disorder (Figure 1c). The reason for this is that since the size of the MeOH molecule is smaller than that of the chiral cavity, the MeOH molecule cannot be fixed in one packing style into the chiral cavity. From X-ray crystallographic analysis of (S)-1/(11R,12R)-2 complex, if (R)-1 and (11R,12R)-2 molecules form a similar 1D-helical column structure, sterical repulsions between the naphthyl group of (R)-1 and anthracene group of (11R,12R)-2 may occur. Therefore, it is thought that (R)-1/(11R,12R)-2 complex could not be formed. In complex I, because the cavities were formed by the selfassembly of 21-helical columns without strong interactions, the size and shape of the cavities are expected to be tuned by altering the packing structure of the helical columns according to guest

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Figure 2. Crystal structure of complex II. (S)-1, (11R,12R)-2, and EtOH molecules are represented as blue, green, and red molecules, respectively. Water molecules are represented by red balls. (a) Helical columnar hydrogen- and ionic-bonded network parallel to the a-axis. (b) View down the a-axis. (c) Packing structure observed along the a-axis. The red arrows indicate the naphthalene edge-to-face interactions.

molecules. Next, the inclusion behavior of two other types of n-alkyl alcohols having longer alkyl chains (EtOH and n-PrOH) was investigated by using them as crystallization solvents. Goodquality colorless crystals II and III were obtained from the EtOH and n-PrOH solutions, respectively, and their crystal structures were analyzed by X-ray crystallographic analysis. The crystal structure of complex II, which contains EtOH, is shown in Figure 2. The X-ray crystallographic analysis revealed that the stoichiometry of this complex is (S)-1/(11R,12R)-2/H2O/EtOH ) 1:2:1:1, with the space group P212121. As expected, this complex also has a 21-helical columnar network structure along the a-axis (parts (a) and (b) of Figure 2), which is mainly formed by the hydrogen and ionic bonds of (S)-1 (Figure 2, represented as blue molecules) and (11R,12R)-2 (Figure 2, represented as green molecules), similar to the case of complex I. As is the case with complex I, the included water molecules (Figure 2,

Imai et al.

Figure 3. Crystal structure of complex III. (S)-1, (11R,12R)-2, and n-PrOH molecules are represented as blue, green, and red molecules, respectively. Water molecules are represented by red balls. (a) Helical columnar hydrogen- and ionic-bonded network parallel to the a-axis. (b) View down the a-axis. (c) Packing structure observed along the a-axis. The red arrows indicate the naphthalene edge-to-face interactions.

represented by red balls) link the two carboxyl groups of (S)-1 through the hydrogen bonds and contribute to the maintenance of the column frame. Chiral cavities are formed by the selfassembly of the 21-column through one type of naphthalene edge-to-face interaction [Figure 2c, indicated by red arrows, 2.65 Å] (Figure 2c). In this cavity, the EtOH guest molecule (Figure 2, represented as red molecules) is trapped with the included water molecules through a hydrogen bond. In contrast to complex I, the EtOH molecule is not observed as disorder. Next, the inclusion mechanism of complex III containing n-PrOH molecules was studied. The crystal structure of complex III is shown in Figure 3. Although the guest alkyl alcohol molecule is changed from MeOH (or EtOH) to n-PrOH, the stoichiometry of this complex is the same as that of I and II, i.e., (S)-1/(11R,12R)-2/H2O/nPrOH ) 1:2:1:1, with the space group P212121. This complex has a characteristic 21-helical column structure composed of (S)-1 (Figure 3, represented as blue molecules), (11R,12R)-2 (Figure 3, represented as green molecules), and water molecules (Figure 3, represented by red balls), similar to the cases of crystals I and II (parts (a) and (b) of Figure 3). Moreover, in

Formation and Crystal Structure of Two-Component Host System

this complex, the chiral cavities are formed by the self-assembly of the 21-column through one type of naphthalene edge-to-face interaction (Figure 3c, indicated by red arrows, 2.72 Å). The guest n-PrOH molecules (Figure 3, represented as red molecules) without disorder are trapped into the cavity with the included water molecules by the same hydrogen bonds, similar to the case of crystals I and II. In complexes I, II, and III, as the alkyl chain of the n-alkyl alcohol becomes longer, i.e., changes from MeOH to n-PrOH, the distances between the (S)-1 molecules along the column (A, Figures 1a-3a) change slightly (12.90, 12.92, and 12.82 Å for I, II, and III, respectively), and the torsion angles of (S)-1 decrease slightly from 67.9° for I and 67.4° for II to 66.3° for III. The distances between the 21-helical columns (B, Figures 1d, 2c, and 3c) along the b-axis increase slightly from 14.21 Å for I and 14.22 Å for II to 14.47 Å for III. Moreover, the distances between the columns (C, Figures 1d, 2c, and 3c) along the c-axis also increase (14.55, 14.56, and 14.58 Å for I, II, and III, respectively). These results suggest that this host system can include n-alkyl alcohol by tuning the packing structure of the shared 21-helical column. Interestingly, a comparison of the crystal structures of the chiral complexes I-III with those of previously studied two-component chiral 1,1′-binaphthyl-2,2′dicarboxylic acid complexes having diamine derivatives reveals that the reported complexes share a similar helical column comprising two 1,1′-binaphthyl-2,2′-dicarboxylic acid molecules and two diamine molecules when observed along the column. However, although chiral complexes I-III also share a similar helical column, this helical column structure comprises two 1,1′binaphthyl-2,2′-dicarboxylic acid molecules and four (11R,12R)9,10-dihydro-9,10-ethanoanthracene-11,12-diamine molecules when observed along the column. From these results, it is concluded that the chiral 1,1′-binaphthyl-2,2′-dicarboxylic acid forms easily a helical column by tuning the component ratio of the component molecules (1,1′-binaphthyl-2,2′-dicarboxylic acid and diamine molecules). Conclusions In conclusion, a novel two-component chiral supramolecular host system of chiral 1,1′-binaphthyl-2,2′-dicarboxylic acid combined with (11R,12R)-9,10-dihydro-9,10-ethanoanthracene11,12-diamine was formed. This chiral host system forms a 21helical column by incorporating water molecules included in the guest solution and can include guest molecules by tuning the packing structure of the shared 21-helical column according to the guest molecule. The chiral cavity in this host system has multiple chiral points (central, axial, and helical), and the size of the cavity changes according to that of the guest molecules. Therefore, it is expected that tunable chiral cavities of this type that can accommodate various guest molecules have great

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potential in enantioselective molecular recognition or asymmetric reactions. Moreover, it is confirmed that these structural informations are useful for the design of novel supramolecular host systems. Acknowledgment. We thank Dr. M. Seki of Mitsubishi Tanabe Pharma Corp. for providing the sample. This work was supported by a Grant-in-Aid for Scientific Research (No. 20750115) from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Supporting Information Available: X-ray crystallographic reports (CIF) of complexes I-III. This information is available free of charge via the Internet at http://pubs.acs.org.

References (1) Atwood, J. L., Davies, J. E. D., MacNicol, D. D., Eds. Inclusion Compounds; Academic Press: New York, 1984; Vols. 1-3. Walba, D. M.; Clark, N. A.; Razavi, H. A.; Parmar, D. S. In Inclusion Phenomenon and Molecular Recognition; Atwood, J. L., Ed.; Plenum Press: New York, 1990. Lehn, J. -M., Atwood, J. L., Davies, J. E. D., MacNicol, D. D., Vogtle, F., Eds. ComprehensiVe Supramolecular Chemistry; Pergamon Press: Oxford, 1996; Vols 1-11. Atwood, J. L., Steed, J. W., Eds. Encyclopedia of Supramolecular Chemistry; Mercel Dekker: New York, 2004. Toda, F., Bishop, R., Eds. PerspectiVes in Supramolecular Chemistry; John Wiley & Sons: Chichester, UK, 2004; Vol. 8. (2) Sada, K.; Shiomi, N.; Miyata, M. J. Am. Chem. Soc. 1998, 120, 10543. Nakano, K.; Hishikawa, Y.; Sada, K.; Miyata, M.; Hanabusa, K. Chem. Lett. 2000, 1170. Kobayashi, Y.; Kodama, K.; Saigo, K. Org. Lett. 2004, 6, 2941. Imai, Y.; Sato, T.; Kuroda, R. Chem. Commun. 2005, 3289. Kodama, K.; Kobayashi, Y.; Saigo, K. Chem.sEur. J. 2007, 13, 2144. Imai, Y.; Kawaguchi, K.; Asai, K.; Sato, T.; Kuroda, R.; Matsubara, Y. CrystEngComm 2007, 9, 467. Kodama, K.; Kobayashi, Y.; Saigo, K. Cryst. Growth Des. 2007, 7, 935. Imai, Y.; Murata, K.; Kawaguchi, K.; Sato, T.; Kuroda, R.; Matsubara, Y. Org. Lett. 2007, 9, 3457. Imai, Y.; Murata, K.; Kawaguchi, K.; Sato, T.; Tajima, N.; Kuroda, R.; Matsubara, Y. Chem. Asian J. 2008, 3, 625. Imai, Y.; Murata, K.; Matsuno, H.; Sato, T.; Kuroda, R.; Matsubara, Y. CrystEngComm 2008, 10, 947. Imai, Y.; Nagasaki, K.; Murata, K.; Kawaguchi, K.; Harada, T.; Nakano, Y.; Sato, T.; Fujiki, M.; Kuroda, R.; Matsubara, Y. CrystEngComm. 2008, 10, 951, and references cited therein. (3) Imai, Y.; Sato, T.; Kuroda, R. Chem. Commun. 2005, 3289. Imai, Y.; Takeshita, M.; Sato, T.; Kuroda, R. Chem. Commun. 2006, 1070. Imai, Y.; Kawaguchi, K.; Sato, T.; Kuroda, R.; Matsubara, Y. Tetrahedron Lett. 2006, 47, 7885. Imai, Y.; Kawaguchi; Murata, K.; Sato, T.; Kuroda, R.; Matsubara, Y. Cryst. Growth Des. 2007, 7, 1676. (4) Sheldrick, G. M. SHELX97, Program for the solution of crystal strctures; University of Goettingen: Goettingen, 1997. (5) Sheldrick, G. M. SHELX97, Program for the refinement of crystal strctures; University of Goettingen: Goettingen, 1997. (6) Spek, A. L. PLATON, Molecular geometry and graphics program; University of Utrecht: Utrecht, 1999. (7) Sheldrick, G. M. SADABS, Program for Empirical Absorption Correction of Area Detector Data; University of Gottingen: Goettingen, 1996.

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