CRYSTAL GROWTH & DESIGN
Synthesis, Structure, and Second-Harmonic Generation of Noncentrosymmetric Cocrystals of 2-Amino-5-nitropyridine with Achiral Benzenesulfonic Acids
2001 VOL. 1, NO. 6 467-471
Hideko Koshima,*,† Mitsuo Hamada,† Ichizo Yagi,‡ and Kohei Uosaki‡ Department of Applied Chemistry, Faculty of Engineering, Ehime University, Matsuyama 790-8577, Japan, and Graduate School of Science, Division of Chemistry, Hokkaido University, N10W8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan Received July 20, 2001
ABSTRACT: A series of noncentrosymmetric cocrystals were prepared from 2-amino-5-nitropyridine (2A5NP) and achiral benzenesulfonic acids (Ar-SO3H), which were designed for nonlinear optical materials. The cocrystals are colorless, and the melting points are fairly high, at around 200 °C. Both components are commonly crystallized in 1:1 ionic forms of 2A5NP+‚Ar-SO3-. The crystal of 2A5NP and 3-methyl-4-nitrobenzenesulfonic acid belongs to chiral space group P212121, in which the 2A5NP+ cation and the anion are alternately stacked with a dihedral angle due to the large sulfonic anion to form column structures. Crystals of 2A5NP with both p-toluenesulfonic acid and p-chlorobenzenesulfonic acid are crystallized into noncentrosymmetric space group Pc and are isomorphic with each other. The 2A5NP+ cation and anion in each crystal are also alternatively stacked to form independently elongated zigzag and layer arrays in perpendicular directions. The crystal of 2A5NP and p-phenolsulfonic acid belongs to acentric space group Pna21, in which herringbone networks of 2A5NP+ cations are arranged in the lattice. The feature of these organic-organic crystals is that the molecular packings are controlled by the aromatic-aromatic interactions as well as multidirectional hydrogen bondings between the 2A5NP+ cations and anions. Second-harmonic generation (SHG) powers measured by the SHEW (second-harmonic generation with evanescent wave) technique revealed the high SHG efficiencies of cocrystals of 2A5NP with p-toluenesulfonic and p-phenolsulfonic acid, comparable to those of the well-known m-nitroaniline and 4-(dimethylamino)-3-acetamidonitrobenzene (DAN), respectively. Chiral and noncentrosymmetric crystals formed from achiral organic compounds1,2 are useful for nonlinear optical (NLO) materials3-5 as well as reactants for absolute asymmetric synthesis.6-8 We already prepared various chiral cocrystals by combining two different achiral molecules.8-11 They involve a series of the helical-type crystals from tryptamine and various achiral carboxylic acids11 and the propeller-type crystals from diphenylacetic acid and aza aromatic compounds.8,9 It has been revealed that cocrystals provide higher possibilities for solid structure design rather than singlecomponent crystals. Masse and co-workers have published a series of organic-inorganic crystals of 2-amino5-nitropyridine (2A5NP; 1) and inorganic acids such as phosphoric acid, which were designed for NLO materials.12-16 Herein we report organic-organic crystals of 1 combined with four achiral benzenesulfonic acids (Ar-SO3H; a-d) and their preliminary SHG properties (Chart 1). The key molecule is 2-amino-5-nitropyridine (1), which has a nitro group as an electron donor and an amino group as an electron acceptor to induce NLO character. Further, the pyridine ring acts as a cationic bonding site, the nitro group as a hydrogen acceptor, and the amino group as a hydrogen donor. The achiral benzenesulfonic acids a-d were selected as strong anionic connectors. * To whom correspondence should be addressed. Fax: +81-89-9279923. E-mail:
[email protected]. † Ehime University. ‡ Hokkaido University.
Chart 1
Both components (2 mmol/2 mmol) were dissolved in methanol (20 mL) and 2 M HCl (1 mL) with gentle heating followed by evaporation to give colorless crystals of 1‚a-1‚d. Several millimeter sizes of single crystals were also easily obtained by slow evaporation at room temperature. The melting points are 218-221, 203-208, 180-183, and 201-203 °C, respectively, which are fairly high due to the salt crystals. The crystals were submitted to X-ray crystallographic analysis to confirm the chiral (1‚a) and noncentrosymmetric (1‚b-1‚d) nature due to belonging to space groups of P212121, Pc, Pc, and Pna21, respectively. The crystal data are summarized in Table 1. Both components are crystallized in a 1:1 ratio of 2A5NP+ cation and Ar-SO3- anion. The ionic species are formed by the
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Table 1. Crystal Data for 1‚a-1‚d formula Mr cryst color cryst size/mm cryst syst space group a/Å b/Å c/Å β/deg cell vol/Å3 calcd density/g cm-3 Z no. of data/params R Rw
1‚a
1‚b
1‚c
1‚d
C12H12O7N4S 356.31 colorless 0.5 × 0.4 × 0.1 orthorhombic P212121 (No. 19) 7.9129(3) 27.337(7) 6.8853(4) 90.0 1489.4(1) 1.589 4 1566/219 0.034 0.089
C12H13O5N3S 311.31 colorless 0.5 × 0.5 × 0.4 monoclinic Pc (No. 7) 11.516(2) 7.914(1) 15.227(2) 91.897(5) 1387.0(4) 1.491 4 2517/396 0.049 0.060
C11H10O5N3SCl 331.73 colorless 0.5 × 0.5 × 0.4 monoclinic Pc (No. 7) 11.738(1) 7.7924(9) 14.921(2) 92.535(7) 1363.4(3) 1.616 4 2475/396 0.043 0.066
C11H11O6N3S 313.28 colorless 0.4 × 0.3 × 0.1 orthorhombic Pna21 (No. 33) 11.9739(7) 17.867(1) 6.3554(4) 90.0 1359.6(1) 1.530 4 1339/190 0.028 0.028
Table 2. Distances (Å) and Angles (D-H‚‚‚O, deg) of the Salt Bridges and Hydrogen Bonds Formed in 1‚a-1‚da 1‚a
1‚b
1‚c
1‚d
interaction
dist
angle
dist
angle
dist
angle
dist
angle
PyN+-H‚‚‚Oa-S N-Ha‚‚‚Ob-S N-Hb‚‚‚Oc-S N-Hb‚‚‚Oa-S PyN4+-H‚‚‚Oa-S N-Ha‚‚‚Ob-S N-Hb‚‚‚Oc-S O-H‚‚‚Ob-S
1.92 (2.67) 2.07 (2.91) 1.92 (2.88)
163 164 170
1.71 (2.67) 2.05 (2.97) 1.94 (2.83)
174 157 133
1.85 (2.65) 1.99 (2.98) 2.23 (2.87)
160 159 151
1.84 (2.72) 1.97 (2.84) 2.28 (3.15) 2.37 (3.08)
173 166 170 151
1.72 (2.69) 2.01 (2.93) 2.15 (2.86)
173 158 131
1.92 (2.72) 2.18 (2.95) 2.03 (2.85)
170 163 154 1.99 (2.77)
178
a
Values in parentheses present the distances between the N and O atoms.
transformation of the proton of the sulfonic acid group of a-d to the nitrogen atom of pyridine of 1. Three kinds of intermolecular bondings are commonly formed between the cation and anion in all four crystals. One is the pyridinium salt bridge (PyN+-H‚‚‚-Oa-S) between the pyridium cation and the Ar-SO3- anion. The other two are the hydrogen bonds (N-Ha‚‚‚-Ob-S and N-Hb‚ ‚‚-Oc-S) between the NH2 group of the 2A5NP+ cation and the Ar-SO3- anion. The distances of salt bridges and hydrogen bonds are in the ranges of 1.7-1.9 and 1.9-2.4 Å, respectively (Table 2). Figure 1 shows the molecular arrangement in the chiral 1‚a. The 2A5NP+ cation and the sulfonic anion are alternatively stacked not in parallel but with a dihedral angle (8.1°) due to the large SO3- anion to form four columns along the a axis (Figure 1b). A cation is connected to the neighboring anion in the same unit cell through the pyridinium salt bridge (PyN+-H‚‚‚-Oa-S) and the hydrogen bond (N-Ha‚‚‚-Ob-S) as well as another anion in the next unit cell through the hydrogen bond (N-Hb‚‚‚-Oc-S) (Figure 1a), forming binding zones along the a and c axes. At the opposite side of the binding zones, the nitro groups of the cation and anion which are not participating in any hydrogen bondings aggregate in mutual repulsion to form nitro zones along the a and c axes. The intermolecular distances of N- - -O (3.05-3.77 Å) and O- - -O (2.953.33 Å) among the nitro groups are short. Further, the pyridine plane and the nitro group of the 2A5NP+ cation and the phenyl plane and the nitro group of the anion are in slightly torsional conformations with dihedral angles of 13.84(9) and 10.52(8)°, respectively. Figure 2 shows the molecular arrangement in the noncentrosymmetric crystal 1‚b. Two independent pairs A and B of 1 and b exist in the asymmetric unit (Figure 2a). The components 1 and b of pair A are alternately arranged with a dihedral angle of 18.5(1)° along the c
Figure 1. Molecular arrangements on the (a) bc plane and (b) ab plane in 1‚a. Yellow, red, blue, dark blue, and white atoms represent sulfur, oxygen, nitrogen, carbon, and hydrogen atoms, respectively.
Nonsymmetric Cocrystals
Crystal Growth & Design, Vol. 1, No. 6, 2001 469
Figure 2. Molecular arrangements on the (a) ac plane and bc plane of (b) A pairs and (c) B pairs in 1‚b. Yellow, red, blue, dark blue, and white atoms represent sulfur, oxygen, nitrogen, carbon, and hydrogen atoms, respectively.
axis to form independent slanting layers of 2A5NP+ cations and sulfonic anions along the b axis (Figure 2b). Both components of pair B also stack alternately with a dihedral angle of 20.7(1)° along the b axis to give independent zigzag structures of 2A5NP+ cations and sulfonic anions along the glide planes on the bc face (Figure 2c). A pyridinium salt bridge (PyN+-H‚‚‚-OaS) and a hydrogen bond (N-Ha‚‚‚-Ob-S) are formed between the perpendicularly neighboring A and B stacks and another hydrogen bond (N-Hb‚‚‚-Oc-S) between the neighboring B stacks (Figure 2a). The intermolecular bindings and the alternative stackings in 1‚b are similar to those in the crystal of 1‚a, but the different
substituent groups, the nitro group of a and the methyl group of b, lead to the different packing arrangements between 1‚a and 1‚b. The crystal 1‚c is isomorphic with 1‚b; the cell constants (Table 1), the intermolecular bondings (Table 2), and the molecular arrangement are very similar to those of 1‚b (Figure 2). This is derived from the similar molecular structures between c and b. The dihedral angles of 1 and b in the A and B pairs are 13.4(6) and 17.8(6)°, respectively. The crystal 1‚d has intermolecular bondings and molecuclar arrangement different from those of 1‚a1‚c, because p-phenolsulfonic acid (d) has a hydroxyl
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Koshima et al. Table 3. SHG Powers of 1‚b and 1‚d SHG relative strength to mNA DAN cutoff wavelength (nm)
Figure 3. Molecular arrangements on the (a) ab plane and (b) bc plane in 1‚d. Yellow, red, blue, dark blue, and white atoms represent sulfur, oxygen, nitrogen, carbon, and hydrogen atoms, respectively.
group as an additional binding site (Figure 3). The anions are bound to each other through the O-H‚‚‚-ObS hydrogen bond between the hydroxyl group and the sulfonic anion to form a 2-fold helical chain in the center of the unit cell along the c axis and opposite helical chains at the corners of the unit cell (Figure 3a). On the other hand, the 2A5NP+ cation is connected to the neighboring anion through the pyridinium salt bridge (PyN+-Hb‚‚‚-Oa-S) and the hydrogen bond (N-Ha‚‚‚ -O -S) as well as another neighboring anion through b the hydrogen bonds (N-Hb‚‚‚-Oc-S and N-Hb‚‚‚-OaS) to form a continuous binding chain along the a axis (Figure 3a). Further, the 2A5NP+ cations are arranged with the 2-fold screw axes to form a herringbone structure along the c axis (Figure 3b). Such a herringbone network is similar to those in the organicinorganic crystals of 2A5NP+ with dichromate14 and phosphate (2A5NPDP).15 Thus, in the case of these organic-organic crystals 1‚a-1‚d, the π-π interaction between the pyridine and phenyl moieties as well as the multidimensional hydrogen bonds control the crystal structures to lead to the alternate stacking of 2A5NP+ cations and Ar-SO3anions and the formation of column, zigzag, layer, and herringbone structures. On the other hand, in the organic-inorganic crystals,12 inorganic anions such as
1‚b
1‚d
0.62 0.05 410
7.31 0.62 415
nitrate,13 dichromate,14 and phosphate,15 lacking aromatic moieties, play a role in controlling the crystal structures by multidimensional hydrogen bonds. Finally, second-harmonic generations (SHG) of the crystals 1‚a-1‚d were measured in powder form by the total reflection method using a hemicylindrical prism, based on the SHEW (second-harmonic generation with evanescent wave) technique.17 The fundamental wave of Nd:YAG (λ ) 1064 nm) was used with an incident angle of 60°. The dependence of laser powers on the signals at 532 nm were measured and compared with those of well-known m-nitroaniline (mNA)18 and 4-(dimethylamino)-3-acetamidonitrobenzene (DAN)19 as standard SHG crystals. The SHG value of 1‚d was larger by an order of magnitude than that of mNA and was comparable to that of DAN (Table 3). The SHG power of 1‚b was comparable to that of mNA. SHG signals of 1‚a and 1‚c were not observed due to their smallness. Absorption spectra of powdered crystals of 1‚b and 1‚d were measured by the reflection method, using barium sulfate as a reference. The cutoff wavelengths determined from the absorption edges were around 410 nm, favorable to NLO materials. The relatively large SHG power of 1‚d suggests the primary contribution of the herringbone arrangement of 2A5NP+ cations, because 2A5NPDP having a similar herringbone structure revealed high SHG efficiency.15 The anionic nature and the helical arrangement of d also seem to have a strong influence on the SHG character. Further measurements of NLO properties by the Maker fringe method as well as refractive indices of 1‚d are necessary. The SHG of 1‚b may be derived from the elongated zigzag and layer arrangements of 2A5NP+ cations. In addition, despite the fact that 1‚b and 1‚c are isomorphic, the larger SHG power of 1‚b as compared to that of 1‚c suggests the influence of substituted groups: the electron-donating methyl group of b and the electron-withdrawing chloro group of c. In the case of 1‚a, the alternate stackings of 2A5NP+ cations and sulfonic anions may disturb the chargetransfer enhancement of 2A5NP+ moieties to lead to the low SHG power. In conclusion, the organic-organic crystal approach using 2A5NP and benzenesulfonic acids confirmed the validity for the design of NLO materials. Acknowledgment. This work was supported by a Grant-in-Aid for scientific research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. Supporting Information Available: X-ray crystallographic information files (CIF) for 1‚a-1‚d. This material is available free of charge via the Internet at http://pubs.acs.org.
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Nonsymmetric Cocrystals (2) (a) Koshima, H.; Matsuura, T. J. Synth. Org. Chem. 1998, 56, 268 (Japanese). (b) Koshima, H.; Matsuura, T. J. Synth. Org. Chem. 1998, 56, 466 (Japanese). (3) In Quantum Electronics Principles and Applications Series; Chemla, D. S., Zyss, J., Eds.; Academic Press: Orlando, FL, 1985. (4) Miyata, S. In Organic Molecules for Nonlinear Optics and Photonics; Messier, J., Kajzar, F., Prasad, P., Eds.; Kluwer: Dordrecht, The Netherlands, 1991. (5) (a) Koshima, H.; Wang, Y.; Matsuura, T.; Mibuka, N.; Imahashi, S. Mol. Cryst. Liq. Cryst. 1996, 275, 233. (b) Koshima, H.; Wang, Y.; Matsuura, T. Mol. Cryst. Liq. Cryst. 1996, 277, 63. (6) Elgavi, J. A.; Green, B. S.; Schmidt, G. M. J. J. Am. Chem. Soc. 1973, 95, 2058. (7) Suzuki, T.; Fukushima, T.; Yamashita, Y.; Miyashi, T. J. Am. Chem. Soc. 1994, 116, 2793. (8) Koshima, H.; Ding, K.; Chisaka, Y.; Matsuura, T. J. Am. Chem. Soc. 1996, 118, 12059. (9) Koshima, H.; Nakagawa, T.; Matsuura, T.; Miyamoto, H.; Toda, F. J. Org. Chem. 1996, 62, 6322. (10) (a) Koshima, H.; Hayashi, E.; Matsuura, T.; Tanaka, K.; Toda, F.; Kato, M., Kiguchi, M. Tetrahedron Lett. 1997, 38, 5009. (b) Koshima, H.; Hayashi, E.; Matsuura, T. Supramol. Chem. 1999, 11, 57. (11) (a) Koshima, H.; Khan, S. I.; Garcia-Garibay, M. A. Tetrahedron: Asymmetry 1998, 9, 1851. (b) Koshima, H.; Honke, S. J. Org. Chem. 1999, 64, 790. (c) Koshima, H.; Honke, S.;
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Fujita, J. J. Org. Chem. 1999, 64, 3916. (d) Koshima, H.; Honke, S.; Miyauchi, M. Enantiomer 2000, 5, 125. (e) Koshima, H.; Miyauchi, M.; Shiro, M. Supramol. Chem., 2001, 13, 137. (f) Koshima, H.; Miyauchi, M. Cryst. Growth Des. 2001, 1, 355. Masse, R.; Bagieu-Beucher, M.; Pecaut, J.; Levy, J. P.; Zyss, J. Nonlin. Opt. 1993, 5, 413. Bagieu-Beucher, M.; Masse, R.; Tranqui, D. Z. Anorg. Allg. Chem. 1991, 606, 59. Pecaut, J.; Masse, R. Acta Crystallogr. 1993, B49, 277. (a) Masse, R.; Zyss, J. Mol. Eng. 1991, 1, 141. (b) Kotler, Z.; Hierle, R.; Josse, D.; Masse, R. J. Opt. Soc. Am. 1992, B9, 534. Zyss, J.; Masse, M.; Bagieu-Beucher, M.; Levy, J. P. Adv. Mater. 1993, 5(2), 120. (a) Kiguchi, M.; Kato, M.; Taniguchi, Y. Appl. Phys. Lett. 1993, 63, 2165. (b) Kiguchi, M.; Kato, M.; Kumegawa, N.; Taniguchi, Y. J. Appl. Phys. 1994, 75, 4332. (c) Kato, M.; Kiguchi, M.; Sugita, N.; Taniguchi, Y. J. Phys. Chem. B 1997, 101, 8856. Southgate, P. D.; Hall, D. S. Appl. Phys. Lett. 1971, 18, 456. Baumert, J.-C.; Twieg, R. J.; Bjorklund, G. C.; Logan, J. A.; Dirk, C. W. Appl. Phys. Lett. 1987, 51, 1484.
CG015542M
