Sulfimidation--a new and versatile strategy for the post ring-closure derivatisation of mixed thia/oxa crowns.

Reaction of [18]aneO(5)S with the aminating agent MSH results in the {[18]aneO(5)SNH(2)}+ cation which may be converted through to the linked crown system [({[18]aneO(5)S}(2)N)]+ via deprotonation, bromination and reaction with the parent crown; significantly, despite their positive charge, both systems can coordinate sodium cations to the ether linkages.