Supramolecular Assembly: Recorded in ‘tape-form’

Abstract

Supramolecular assemblies, as distinct from ‘co-ordination polymers’ generally owe their occurrence to intermolecular interactions at the medium (e.g. hydrogen-bonding) to weak (e.g. Van der Waal’s) end of the scale. Though individually explained and successfully described by theory, much still remains unknown when these interactions are placed in competition with one-another and ultimately, what the net effect of multiple contacts will confer on intermolecular geometry. It is this void that has spawned the discipline now known as crystal engineering [1] - the systematic investigation of supramolecular interactions, how they behave and the effects they cause on molecular packing motifs. As the knowledge base in this field has increased, it has given rise to the concept of the supramolecular synthon – the spatial arrangements of intermolecular interactions which play the same rôle in supramolecular synthesis as conventional synthons do in organic synthesis. More recently Desiraju [2,3] and others [4,5] have described a wide variety of supramolecular synthons which can be used to control the architecture of organic molecules. Figure 1: Tripodal interaction in the one of the supramolecular synthons under investigationIt is on the key principles of crystal engineering that the study of known and robust supramolecular synthons, found to form “tape-like” assemblies [5] [Fig. 1] have been forged. In this poster, the results of some detailed comparative studies on the careful addition of various supramolecular contacts, conditions and/or constraints to the periphery of these “tapes” will be described. These investigations have led to some interesting discoveries [6] due to their impact on the intermolecular assembly of the primary “tape-like” structure and on secondary inter-“tape” architecture