An Investigation of Supramolecular Interactions in some Electronically Active Organic and Organometallic Materials

The opening section of this thesis reviews the application of the concepts of supramolecular chemistry to the control of the solid-state behaviour of organic and organometallic materials. The application of these concepts to our understanding of (i) electronically active salts based on TCNQ and its analogues; and (ii) simple 2,6-disubstituted pyridine derivatives is then reported.Two series of salts have been prepared based on (a) the Mn+ (mnt2-)2) anion and (b) on radialene and triazine analogues of TCNQ.- (TCNQ = 7,7,8,8-tetracyanoquinodimethane). For both these series, counter cations chosen for study were either (i) simple ammonium and pyridinium cations; (ii) cyaninium cations or (iii) ionophore-encapsulated alkali metal cations. Detailed comparison of the solid-state behaviour of these materials has revealed that in addition to electrostatic association, specific C-H......X interactions play an important structure forming role.In a parallel study C-H......X interactions have been found to play a crucial role in the solid-state behaviour of pyridine 2,6-dicarboxylate esters, where a triple interaction of this type leads to the formation of infinite tapes in the solid-state. This contact, a novel supramolecular synthon, is insensitive to the nature of the ester side arms. Preliminary studies on the effect of modifying the nature of this contact are also reported. The analogous pyridine 2,6-dicarboxamides do not show this phenomenon, but prefer a U-shaped conformation which is shown to be ideal for metal ion complexation. In particular 2,6-bis-N,N-(2-pyridylmethyl) pyridine dicarboxamide reacts with nickel (II) and copper (II) to form neutral complexes, which in the latter case are helical. However with cobalt (III) a 2:1 ligand-to-metal complex is formed.