Doubly helical, chiral crown thioether fully preorganized for planar coordination

Abstract

Optically active 18-membered quadridentate crown thioethers with double helicity, (+)-(R,R)- and (–)-(S,S)-bitol₂Me₄[18]S₄ and the non-helical meso-compound are prepared and their reactions with ruthenium(II) give trans-[RuCl₂{(+)-(R,R)-bitol₂Me₄[18]S₄}] and the meso-analogue of D₂ and C_2h, symmetries, respectively; free (+)-(R,R)-bitol₂Me₄[18]S₄ and the racemic ruthenium(II) complex have been structurally characterized.