´
5 A. Lemmerer, N. B. Bathori and S. A. Bourne, Acta Crystallogr.,
Sect. B: Struct. Sci., 2008, 64, 780–790.
6 C3A: 14–17 1C; C4A: ꢁ7.5 1C; C5A: 3–5 1C and C6A: 30 1C.
7 (a) B. Sarma, S. Roy and A. Nangia, Chem. Commun., 2006,
4918–4920; (b) K. M. Anderson, K. Afarinkia, H.-W. Yu,
A. E. Goeta and J. W. Steed, Cryst. Growth Des., 2006, 6,
2109–2113; (c) K. M. Anderson, A. E. Goeta, K. S. B. Hancock
and J. W. Steed, Chem. Commun., 2006, 2138–2140;
(d) G. S. Nichol and W. Clegg, Cryst. Growth Des., 2006, 6,
451–460; (e) K. M. Anderson, M. R. Probert, C. N. Whiteley,
A. M. Rowland, A. E. Goeta and J. W. Steed, Cryst. Growth Des.,
2009, 9, 1082–1087.
8 (a) I. Halasz, M. Rubcic, K. Uzarevic, I. Ðilovic and E. Mestrovic,
´ ´ ´ ´
New J. Chem., 2011, 35, 24–27; (b) A. Mukherjee and
G. R. Desiraju, Chem. Commun., 2011, 47, 4090–4092.
9 H.-Y. Ye, J.-Z. Ge, F. Chen and R.-G. Xiong, CrystEngComm,
2010, 12, 1705–1708.
´
10 S. Karki, T. Friscic and W. Jones, CrystEngComm, 2009, 11,
470–481.
Fig. 13 DSC traces of a series of three subsequent heating/cooling
runs starting with form II of 4, showing the phase transition from II to
I, the reverse phase transition from I to II, and the fusion endotherm
11 Bruker, SAINT+, Version 6.02 (Includes XPREP and SADABS),
Bruker AXS Inc., Madison, Wisconsin, USA, 2004.
12 G. M. Sheldrick, SADABS, Universitat Gottingen, Germany,
2004.
¨
¨
of form I. The heating and cooling rates are 10 K minꢁ1
.
13 L. J. Farrugia, J. Appl. Crystallogr., 1999, 32, 837–838.
14 G. M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr.,
2008, 64, 112–122.
suggest that a crystal engineer has much to gain by working in
the area of co-crystals.
15 M. C. Burla, R. Caliandro, M. Camalli, B. Carrozzini,
G. L. Cascarano, L. De Caro, C. Giacovazzo, G. Polidori,
D. Siliqi and R. Spagna, J. Appl. Crystallogr., 2007, 40, 609–613.
16 L. J. Farrugia, J. Appl. Crystallogr., 1997, 30, 565.
17 A. L. Spek, J. Appl. Crystallogr., 2003, 36, 7–13.
18 K. Brandenburg, Diamond, Version 2.1e, Crystal Impact GbR,
Bonn, Germany, 1996–2001.
19 C. F. Macrae, P. R. Edgington, P. McCabe, E. Pidcock,
G. P. Shields, R. Taylor, M. Towler and J. van de Streek,
J. Appl. Crystallogr., 2006, 39, 453–457.
20 (a) P. Vishweshwar, A. Nangia and V. M. Lynch, Cryst. Growth
Des., 2003, 3, 783–790; (b) M. Du, Z.-H. Zhang, X.-G. Wang,
H.-F. Wu and Q. Wang, Cryst. Growth Des., 2006, 6, 1867–1875;
(c) M. Du, Z.-H. Zhang, X.-J. Zhao and H. Cai, Cryst. Growth
Des., 2006, 6, 114–121.
Acknowledgements
The University of the Witwatersrand and the Molecular
Sciences Institute are thanked for providing the infrastructure
and financial support to do this work. Dr Clive Oliver is
thanked for solving the crystal structure of 1. AL thanks the
Friedel Sellshop Grant for additional financial support.
Notes and references
1 (a) V. Bertolasi, L. Pretto, P. Gilli, V. Ferretti and G. Gilli, New J.
Chem., 2002, 26, 1559–1566; (b) C. B. Aakeroy, N. Schultheiss,
J. Desper and C. Moore, New J. Chem., 2006, 30, 1452–1460;
(c) K. K. Arora, M. S. Talwelkar and V. R. Pedireddi, New J.
Chem., 2009, 33, 57–63; (d) H. F. Clausen, M. S. Chevallier,
M. A. Spackman and B. B. Iversen, New J. Chem., 2010, 34,
21 C. B. Aakeroy, A. B. Grommet and J. Desper, Pharmaceutics,
¨
¨
2011, 3, 601–614.
22 S. L. Childs, G. P Stahly and A. Pak, Mol. Pharmaceutics, 2007, 4,
323–338.
23 As calculated using the ACD Labs module in SciFinder. For
comparison, the pKa values of their acyclic isomers show the same
trend and relative values.
193–199; (e) J. Martı
A. Morte-Rodenas, F. Guo, Z. Glavcheva-Laleva, K. Ta-stemur,
´
´
-Rujas, B. M. Kariuki, C. E. Hughes,
¨
L.-L. Ooi, L. Yeo and K. D. M. Harris, New J. Chem., 2011, 35,
1515–1521.
2 A. D. Bond, CrystEngComm, 2007, 9, 833–834.
3 (a) G. P. Stahly, Cryst. Growth Des., 2007, 7, 1007–1026; (b) B. R
Bhogala and A. Nangia, New J. Chem., 2008, 32, 800–807;
(c) S. L. Childs and K. I Hardcastle, Cryst. Growth Des., 2007, 7,
1291–1304; (d) C. B. Aakeroy and D. J. Salmon, CrystEngComm,
¨
2005, 7, 439–448; (e) W. Jones, W. D. Motherwell and A. V. Trask,
¨
MRS Bull., 2006, 341, 875–879; (f) O. Almarsson and
24 (a) T. Steiner, Acta Crystallogr., Sect. B: Struct. Sci., 2000, 56,
673–676; (b) K. M. Anderson and J. W. Steed, CrystEngComm,
2007, 9, 328–330.
25 (a) J. W. Steed, CrystEngComm, 2003, 5, 169–179;
(b) G. R. Desiraju, CrystEngComm, 2007, 9, 91–92.
26 D. Das, R. Banerjee, R. Mondal, J. A. K. Howard, R. Boese and
G. R. Desiraju, Chem. Commun., 2006, 555–557.
27 K. M. Anderson, A. E. Goeta and J. W. Steed, Cryst. Growth Des.,
2008, 8, 2517–2524.
M. J. Zaworotko, Chem. Commun., 2004, 1889–1896;
(g) N. Schultheiss and A. Newman, Cryst. Growth Des., 2009, 9,
2950–2967.
28 K. M. Anderson, M. R. Probert, A. E. Goeta and J. W. Steed,
CrystEngComm, 2011, 13, 83–87.
29 M. C. Etter, Acc. Chem. Res., 1990, 23, 120–126.
4 R. Boese, D. Blaser and G. Jansen, J. Am. Chem. Soc., 2009, 131,
2104–2106.
´
30 N. B. Bathori, A. Lemmerer, G. A. Venter, S. A. Bourne and
M. R. Caira, Cryst. Growth Des., 2011, 11, 75–87.
¨
c
2252 New J. Chem., 2012, 36, 2242–2252
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012