Benzo-cis-cyclohexano-14-crown-4 and its lithium thiocyanate complex

The structures of a 14-crown-4 ether containing both benzo and cyclohexano substituents, 2,6,13,17-tetraoxatricyclo[16.4.0.0 (7,12)]docosa-1(18),19,21 -triene, C18H26O4, and its lithium complex, [2,6,13,17-tetraoxatricyclo[16. 4.0.0 7,12]docosa-1(18),19,21-triene-kappa(4)O](thiocyanato-N)lithium(I), [ Li(NCS)(C18H26O4)], are presented. The conformation of the free crown, (I), is not preorganized for cation binding, as its donor dipoles are oriented towards opposite sides of the crown ring. The Li + -crown complex, (II), ex hibits two formula units in the asymmetric unit. The binding conformation o bserved in (II) does not completely reorient the dipoles to one point, resu lting in a long Li-O bond length [2.068 (5) and 2.073 (5) Angstrom].