Formation of [2+2] diruthenium(II) metallomacrocycles from ligands containing 2,2 `: 6 `,2 ``-terpyridine domains linked through flexible polyethyleneoxy spacers

The syntheses of three ligands containing two terpy metal-binding domains linked through flexible polyethyleneoxy spacers are described. These ligands have been utilised as building blocks in a two-step process for the formation of a series of dinuclear ruthenium(II) metallomacrocycles of the type [Ru2L2](4+). Employing a two-step methodology allows the formation of homoleptic ([Ru2L2](4+)) and heteroleptic ([Ru2LL`](4+)) species in which the ligands differ in the length of the polyethyleneoxy spacer connecting each terpy motif. Homoleptic metallomacrocycles have been characterised through single crystal X-ray diffraction studies, while 2D-NMR spectroscopy has been employed for the characterisation of the heteroleptic species.