Interesting conformational and substitutional disorder in the crystal structures of three homologous crowns

The structures of three members of a homologous family of diphenylamine-containing crowns, 2-chloro-6,7,9,10-tetrahydro-16H-dibenzo[b,k][1,4,7,10]monoazatrioxacyclododecine (NAI), 2-chloro-6,7,9,10,12,13-hexahydro-19H-dibenzo[b,n][1,4,7,10,13]monoazatetraoxacyclopentadecine (NAII), 2-chloro-6,7,9,10,12,13,15,16-octahydro-22H-dibenzo[b,q][1,4,7,10,13,16]monoazapentaoxacyclooctadecine] (NAIII), are reported, compared and trends are established. The largest crown (an 18-crown-6-type) presents an ability to form a molecular compound with water molecules spontaneously. The propeller-like conformational behaviour of the two phenyl rings leads to the presence of two chiral conformers in the unit cell of the crystals. Additionally, due to the conformationally non-equivalent role of the two phenyl rings, the chlorine substitution leads to two further species, resulting in four different conformers in each crystal structure. The presence of so many species in one crystal generates an interesting type of disorder in two of the three cases.

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