Macrocyclic Ethers and Their Inclusion Complexes

Abstract

Abstract The synthesis and characterisation of eleven new macrocyclic ethers (up to 96‐membered [6+6] gigantocycle) with well‐defined cavities are described. Syntheses of the macrocycles M1–M7 were performed under high‐dilution conditions. A “supramolecular” purification method was used for the small [2+2] macrocycles M3–M7 , which separated selectively from the reaction mixture on recrystallisation from a dichloromethane/diethyl ether solution mixture. This proved to be an excellent method for purifying [2+2] macrocyclic ethers containing 1,1‐diphenylmethane moieties, and the separation was nearly quantitative. Molecular inclusion of dichloromethane in the cavities of noncovalently bonded macrocyclic ethers M2–M5 was studied by X‐ray diffraction in the solid state. Additionally, clathrate formation was found for macrocycles M1 (including diethyl ether), M2 (including water), M6 (including benzene) and M7 (including benzene).