Three Complexes of a [2.2]Cryptahemispherand

The macrocyclic host 36,37,38-trimethoxy-5,10,15-trimethyl-22,25,30,33-tetraoxa-1,19-diazapentacyclo [17.8.8.1^3,7.1^8,12.1^13,17]octatriaconta-3,5,7(38),8,10,12(37),13,15, 17(36)-nonaene contains a somewhat flexible cavity lined with seven O atoms and two N atoms. The structures of three of its complexes are reported here: that with sodium thiocyanate, (I) {[Na(C₃₈H₅₂N₂O₇)] SCN}, at 296 K, and those with potassium thiocyanate, (II) {[K(C₃₈H₅₂N₂O₇)]SCN.H₂O}, and caesium perchlorate, (III) {[Cs(C₃₈H₅₂N₂O₇)]ClO₄·H₂O}, at 156 K. The host adapts well to Cs⁺, with effective ninefold coordination; it adapts nearly as well to K⁺, but is not sufficiently flexible to be a good complexer for the much smaller Na⁺ ion. In structure (II) and in structure (III), a water molecule forms hydrogen bonds between an O atom of the host and an atom of the anion [N of SCN^- in (II), O of ClO₄^- in (III)].

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