[[pi]]-[[pi]] STACKING IN MODEL DYE HOSTS. C.M. Murray, J.F. Malone, R. Docherty, A.J. Lavery, G. Stewart.

Weak hydrogen bonds e.g. C-H...O and weak interactions e.g. [[pi]]-[[pi]] stacking and T-bonding have been shown to have a role within crystal structure¹. The [[pi]]-[[pi]] stacking interaction, though weak, is significant in the structure of 1,3 Bis(((3-hydroxyphenyl)amino)carbonyl)benzene which is reported.

This interaction has been quantified using the HABIT program². Semi-empirical calculations of the heat of formation show agreement between the preferred conformation in the gas phase and the single crystal X-Ray diffraction structure. Similar structures retrieved from the Cambridge Structural Database confirm the importance of the [[pi]]-[[pi]] interaction for not only single molecule asymmetric units of this type but also asymmetric units which contain hydrated species or co-crystals. Quantification of the values is reported and the conformational preference is also investigated.

1 G.R. Desiriaju Acc. Chem. Res. 1991, 24, 290-296. A.D. Hamilton et al J. Am. Chem. Soc. 1988, 110, 6561-6562. D.R. Boyd et al J. Am. Chem. Soc. 1996 in press.

2 G. Clydesdale, R. Docherty, K.J. Roberts Computer Physics Communications 64 (1991) 311-328.