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

Abstract

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.