| Abstract |
An unexpected dimerization of a cryptand L with N5O3 donors, C33H45N5O3, was observed in aqueous solution when L was treated by hydrochloric acid in MeOH and washed with EtOH. The crystal dimerization product is a complex (H2L2)(2+.)2Cl(-.)5HCl(.)18H(2)O (1) (where the neutral dimeric cryptand L-2 is C66H90N10O6). The crystal complex L(2.)2HCl(.)3H(2)O (2) was obtained when complex 1 was neutralized with aqueous solution of NaOH. The two complexes have been characterized by X-ray diffraction, NMR and MS. The conformation of L-2 in 1 is endo-endo-endo-endo, and the two nitrogen atoms of four bridgehead tertiary nitrogen atoms of L-2 are protonated. However, conformation of L-2 in 2 is endo-exo-endo-exo, and the L-2 is neutral. |
