Synthesis and supramolecular chemistry of broader rim tetraolefinic calix[4]arenes.

Synthesis of novel broader rim calix[4]arene derivatives has been carried out, initially, using palladium coupling reactions. Further derivatisation and investigation into host-guest chemistry of these novel compounds has also been accomplished. Conditions have been optimised for the coupling of both aromatic and aliphatic acrylates. Stereospecific formation of the all trans coupled product of an exclusively beta Heck coupling has been observed throughout. All compounds (of the type II) have been obtained in good yield. Synthetic methodology for the generation of receptor libraries (be they static or dynamic) via the coupling of both tertiary and secondary aciylamide species using a palladium catalyst has been accomplished. Some of the secondary aciylamides possess the capacity (by virtue of pre-arrangement of amidic hydrogen bonding motifs) to form dimers via H-bonding in non-polar solution. The binding of a commercial pesticide (TMTD) by an acrylamidocalix[4]arene is reported and corroborated by NMR and ESI-MS data. The ability to couple formyl functionalised acrylates to the broader rim has allowed the preparation of a small library of deep cavity receptors in the form of tetra-transimines. These deep cavity calix[4]arene receptors could be obtained and are folly characterised. In the case of dynamic combinatorial libraries the principle of utilising a guest molecule to template or at least effect a specific outcome of imine forming reactions at four aldehydic sites on the broader rim of the calix[4]arene has also been illustrated. This provides support for the principles of formation of dynamic combinatorial libraries and further proposes calix[4]arene building blocks as being useful in their construction