1,4,7-Tris(2,2′-bipyridyl-5-ylmethyl)-1,4,7-triazacyclononane (L1), a powerful tris(2,2′-bipyridyl) chelating macrocyclic ligand. X-Ray structure of [Ru(L1H)][PF6]3, a complex containing a strongly trapped proton

Abstract

A new powerful tris(2,2′-bipyridyl) chelating ligand, 1,4,7-tris(2,2′-bipyridyl-5-ylmethyl)1,4,7-triazacyclononane (L¹), has been synthesised and characterised, and an X-ray structure of [Ru(L¹H)]³⁺ obtained; in the complex all three bipyridyl groups are coordinated, with a fairly regular octahedral Ru^II geometry, and although the azamacrocyclic nitrogen-atoms are non-coordinating to Ru^II, in aqueous solution they trap a single proton in the cavity between the macrocycle and the Ru^II, and which cannot be removed even at high pH.