Iron(II) complexes utilising terpyridine containing [2]rotaxanes as ligands

A terpyridine chelating group is incorporated into a cationic (dipyridinium)ethane axle and self-assembly synthesis used to create three [2]rotaxanes utilising 24-membered crown ether wheels: 24-crown-8, dibenzo-24-crown-8 and dinaphtho-24-crown-8 ether. The resulting [2]rotaxanes are characterised by 1H NMR spectroscopy, X-ray crystallography and mass spectrometry. The ability of these rotaxanes to act as ligands is demonstrated by the formation of bis(terpy) chelate complexes of Fe(II). The effect of using a rotaxane as a ligand is probed by UV-vis absorption spectroscopy of the Fe(II) complexes.