We have recently observed that, in the solid state, pyridine 2,6-dicarboxylates self assemble to form infinite tapes (as shown below) through a front-to-back triple C-H•••X contact (where X = N, O).
This contact is robust, tolerating a wide range of substituents (R = alkyl, arylmethyl, heteroarylmethyl, chloro, etc). We have also found that other substitution patterns around the pyridine core can result in tape assembly but such systems are much more sensitive to the nature of the peripheral substituents.
We are currently investigating the extent to which this contact persists into the liquid phase (solution or melt) using a variety of spectroscopic techniques and are attempting to quantify the strength of the contact and how this varies with different side groups.
We are also exploring the use of this assembly process for the design of functional organic materials.
M. C. Grossel, C. A. Golden, J. R. Gomm, P. N. Horton, D. A. S. Merckel, M. E. Oszer and R. A. Parker, CrystEngComm, 42, 1 (2001);
M. C. Grossel, M. B. Hursthouse, and J. B. Orton, CrystEngComm, 7, 279 (2005);
M. C. Grossel, A. N. Dwyer, B. Hursthouse, and J. B. Orton, CrystEngCom, 8, 123 (2006).