Dinuclear acetylide-bridged ruthenium(ii) complexes with rigid non-aromatic spacers

Abstract

Rigid dinuclear ruthenium complexes containing non-aromatic caged and polycyclic spacer groups were synthesised and characterised. The complexes, [trans,trans-{Ru(dmpe)₂(CC^tBu)}₂(μ-CC–X–CC)], where X = 1,4-bicyclo[2.2.2]octane (C₈H₁₂) or 1,12-p-carborane (p-C₂B₁₀H₁₀), were formed via the metathesis of terminal organic bisacetylenes with the methylruthenium complex, [trans-Ru(dmpe)₂(CH₃)(CC^tBu)], under mild conditions. Electrochemical studies demonstrated electronic interactions across the non-aromatic caged and polycyclic spacers was less than in the analogous complex with an aromatic spacer group, [trans,trans-{Ru(dmpe)₂(CC^tBu)}₂(μ-CC-p-C₆H₄-CC)]. Mononuclear complexes, [trans-Ru(dmpe)₂(CC^tBu)(CC–X–CCH)], were also synthesised. [trans-Ru(dmpe)₂(CC^tBu)(CC–C₈H₁₂–CCH)] and [trans,trans-{Ru(dmpe)₂(CC^tBu)}₂(μ-CC–p-C₂B₁₀H₁₀–CC)] were structurally characterised by X-ray crystallography.