Enabling tetracationic cyclophane production by trading templates

Abstract

The time taken to produce the ubiquitous and promiscuous receptor, which has become known as the little "blue box", has been halved as a result of using a pH-responsive derivative of 1,5-diaminonaphthalene to displace the template employed during its synthesis. The fact that this surrogate trades places within the cavity of the "blue box" is the key to the time-saving for the simple reason that it leaves the lock, so-to-speak, as soon as it becomes protonated by a strong acid. During the subsequent full characterisation of the "blue box", it was discovered that the tetracationic cyclophane exists at least in two different polymorphs in the solid state. © The Royal Society of Chemistry 2010.