Synthesis and solid-state supramolecular chemistry of a series of pyridinium-derived zwitterions

A new class of potential supramolecular building blocks is presented. The synthesis and crystal structures of seven novel pyridinium-derived zwitterionic compounds are discussed, as well as two related pyridinium salts. The synthesis of these compounds was achieved by simple solution methods using mild conditions, and the products were isolated as single crystals with no further purification required. Hydrogen-bonded chains were found to be prevalent in all of the crystal structures of the zwitterions and due to the robust nature of this motif, these compounds have the potential to be exploited in future supramolecular studies. There is a large scope for the synthesis of related zwitterionic compounds using a range of pyridyl substituents with varied functional groups. These zwitterionic compounds show great potential as a new class of supramolecular building block in the formation of ionic- as well as metal–organic frameworks.