Structural Change of a Line ar Polyether upon Complex Formation. 1.11-Bis(2-acetylaminophenoxy)-3.6.9-trioxaundecane and its KSCN Complexa

The title compound (1) was crystallized as free ligand and as its (1 · KSCN) · H O complex. Crystallographic data are, for the former: space group C 2/c, a = 31.110(9), b = 4.608(4), c = 17.188(6) Å, β = 105.27(8)°, Z = 2, D = 1.25 gem ; for the latter: space group P2 , a = 11.044(3), b = 18.310(4), c = 14.485(4) Å, β = 97.49(2)°, Z = 4, Dm = 1.27 gem . Crystal structures were solved by direct methods using X-ray diffraktometer data and least squares refinements converged at 10.8% for 1 and at 7.6% for (1 · KSCN)2 · H2O. The free ligand (1) is S-shaped and, upon K -complexation, changes signs of some gauche O-C-C-O torsion angles while C-C-O-C angles remain trans. In (1 · KSCN) · H O, there are two complex molecules 1 A · KSCN · H O (I) and 1 B · KSCN (II). The ligands are wrapped circularly around K and coordinated with only four of the five polyether oxygens. K interacts further with H O in (I) and with N of SCN in II and, in both complexes, with acetylamino oxygen of adjacent 1. The latter interaction leads to polymeric structures not observed previously for similar complexes.