DOI: 10.1021/cg901132g
Cocrystal and Salts of 2,20 ,6,60 -Tetracarboxybiphenyl with Bis(pyridyl) Derivatives: Eight-fold Interpenetrated Diamondoid and Layered Networks
2009, Vol. 9 5006–5008
Sandipan Roy, Goutam Mahata, and Kumar Biradha* Department of Chemistry, Indian Institute of Technology, Kharagpur-721302, India Received September 16, 2009; Revised Manuscript Received November 2, 2009
ABSTRACT: The cocrystallization reactions of 2,20 ,6,60 -tetracarboxybiphenyl with bis(4-pyridyl) ethylene and 4,40 -bipyridine were studied, and it was found that molecular symmetry (pseudo-S4) has been transferred into supramolecular symmetry to form an 8-fold interpenetrated diamondoid network only in the case of cocrystals but not in the case of salts. The supramolecular synthesis of multicomponent organic materials is of importance due to their functional properties.1 The facile way of synthesizing these cocrystals is to consider the components containing complementary functional groups such as pyridine and -COOH; to date, several multicomponent cocrystals containing various network geometries were prepared using these two functional groups.2 Among various geometries of three-dimensional networks, the diamondoid network is the most popular and attractive, as it resembles the super-adamantanoid.3 The easiest way to design these networks is to consider the molecules containing S4 or pseudo-S4 symmetry with hydrogen bonding functional groups. In principle, the use of linkers between such tetrahedral molecules is expected to increase the cavity sizes of the diamondoid network and therefore the self-interpenetration of the networks. However, in practice, the transfer of molecular symmetry to supramolecular symmetry is not an obvious exercise in crystal engineering, as there are several factors that influence the final structural outcome. It is often true that the molecules with S4 symmetry prefer square nets than diamondoid networks. The complexity in obtaining required network geometries increases further in the case of two component systems. Accordingly, to our knowledge, to date, there exists only two examples of two component hydrogen bonded diamondoid networks.4 Here we would like to present our studies on the cocrystals of 2,20 ,6,60 tetracarboxybiphenyl (H41) with 4,40 -bipyridine (bpy) and 4,40 bipyridylethylene (bpe). These studies are aimed at obtaining diamondoid or square networks, as the molecule H41 can exhibit the S4 symmetry. It is important to note here that the molecules of H41 assemble to form a square grid network in its crystal structure instead of a diamondoid network.5 Our studies here show that the diamondoid network in the cocrystals of H41 is indeed possible subjected to reaction conditions and linkers. However, the probability in obtaining the square networks is found to be higher than that of obtaining an adamantanoid network.
*To whom correspondence should be addressed. E-mail: kbiradha@ chem.iitkgp.ernet.in. Fax:þ91-3222-282252. Telephone: þ91-3222-283346. pubs.acs.org/crystal
Published on Web 11/10/2009
The crystallization of H41 (0.031 mmol) with bpe (0.062 mmol) in MeOH (>12 mL) resulted in the single crystals of a salt [H31]2[H2bpe] 3 2MeOH (2) but not in the anticipated cocrystals.6 In the crystal structure of 2, the asymmetric unit is constituted by one unit of H31, half a unit of H2bpe, and one unit of MeOH. The H31 moiety contains one intramolecular hydrogen bond between the deprotonated carboxylate O-atom and -COOH (O 3 3 3 O, O-H 3 3 3 O: 2.510(2) A˚, 177(2)°); these anions self-assemble to form a one-dimensional chain via O-H 3 3 3 O hydrogen bonds (O 3 3 3 O, O-H 3 3 3 O: 2.642(3) A˚; 169(4)°; 2.550(2) A˚, 173(2)°). The anionic chains are linked by the H2bpe units via charge assisted and donor bifurcated N-H 3 3 3 O hydrogen bonds (N 3 3 3 O, N-H 3 3 3 O: 2.766(3) A˚, 136(2)°; 2.938(3) A˚, 134(2)°) to form a layer structure with rectangular cavities of dimension 9.2 14.8 A˚2 (Figure 1). These layers have highly corrugated geometry, and therefore, the cavities of the layers are filled by the interdigitation of the layers. The MeOH molecules are bound to the CO of COOH via O-H 3 3 3 O hydrogen bonds. In anticipation of the expected diamondoid network, the crystallization reaction of H41 with bpe has been tried under various conditions such as changing the concentration and varying the solvents. In this exercise we found that the MeOH ( 2σ(I), 2.09 < θ < 25.50°, final R-factors R1 = 0.0532, wR2 = 0.1630. (7) Crystal data for 3: monoclinic, C2/c, a = 10.530(2) A˚, b = 16.484(2) A˚, c = 20.026(3) A˚, β = 92.652(4)°, V = 3474.2(9) A˚3, Z = 4, Dc = 1.329 g cm-3, 1961 reflections out of 3541 unique reflections with I > 2σ(I), 2.04 < θ < 26.36°, final R-factors R1 = 0.0604, wR2 = 0.1695. (8) Crystal data for 4: triclinic, P1, a = 8.2046(4) A˚, b = 13.0131(6) A˚, c = 13.1983(6) A˚, R = 65.624(1)°, β = 74.404(1)°, γ = 72.316(1)°, V = 1206.05(10) A˚3, Z = 2, Dc = 1.428 g cm-3, 3566 reflections out of 4909 unique reflections with I > 2σ(I), 2.09 < θ < 25.50°, final R-factors R1 = 0.0570, wR2 = 0.1886. (9) Crystal data for 5: monoclinic, Cc, a = 17.703(1) A˚, b = 8.383(5) A˚, c = 17.403(1) A˚, β = 108.626(2)°, V = 2447.4(3) A˚3, Z = 4, Dc = 1.418 g cm-3, 4066 reflections out of 4405 unique reflections with I > 2σ(I), 2.43 < θ < 26.50°, final R-factors R1 = 0.0360, wR2 = 0.0986. (10) Crystal data for 6: triclinic, P1, a = 12.6784(4) A˚, b = 12.9302(4) A˚, c = 15.1054(5) A˚, R = 75.356(1)°, β = 71.286(1)°, γ = 63.366(1)°, V = 2079.06(11) A˚3, Z = 1, Dc = 1.487 g cm-3, 6136 reflections out of 8807 unique reflections with I > 2σ(I), 2.09 < θ < 25.50°, final R-factors R1 = 0.0495, wR2 = 0.1650. (11) Biradha, K.; Mahata, G. Cryst. Growth Des. 2005, 5, 49. (12) (a) Mohamed, S.; Tocher, D. A.; Vickers, M.; Karamertzanis, P. G.; Price, S. L. Cryst. Growth Des. 2009, 9, 2881. (b) Aaker€oy, C. B.; Fasulo, M. E.; Desper, J. Mol. Pharmaceutics 2007, 4, 317. (13) (a) Santra, R.; Ghosh, N.; Biradha, K. New J. Chem. 2008, 32, 1673. (b) Santra, R.; Biradha, K. Cryst. Growth Des. 2009, 9, 4969. (14) Han, J.; Yau, C.-W.; Lam, C.-K.; Mak, T. C. W. J. Am. Chem. Soc. 2008, 130, 10315.
