A singly stranded, helical di-ruthenium(II) complex of a novel 6,6-ethynyl-linked bis(terpyridine) ligand. Distortion of the ethyne linkage and inversion of helicity

Abstract

The new, ethynyl-bridged ditopic ligand, 1,2-bis[4′-(4-methylphenyl)-2,2′∶6′2′′-terpyridin-6-yl]ethyne (L) was prepared and used in the formation of the helical dinclear complex [L{Ru(ttpy)}₂][PF₆]₄ (ttpy=4′-(4-methylphenyl)-2,2′∶6′,2′′-terpyridine), whose crystal structure exhibits pronounced bending of the central ethynyl bridge and whose solution NMR spectra indicate a rapid inversion of helicity at 335 K.