Chiral 1,2-ethanediyl-spaced quaterpyridines give a library of cyclic and double helicates with copper(I)

A new enantiomeric pair of ligands in which a 2,2′:6′,2″:6″,2″′-quaterpyridine has been split into two 2,2′-bipyridine binding domains by a CH2CH2 spacer has been prepared: reaction with Ag(I) gives dinuclear double helicates whereas Cu(I) gives a library of {CuL}nn+ complexes (n = 2,3,4,5) of which the compounds with n = 2,3 have been structurally characterised as double helicates and cyclohelicates respectively.