THE CRYSTAL AND MOLECULAR STRUCTURE OF 1,4,7,11,14,17-HEXATHIACYCLOEICOSAN-9,19-DIONE-SOLID-STATE CONFORMATION OF A MACROCYCLIC DIKETOHEXATHIOETHER¹

Abstract

Abstract The macrocyclic hexathioether, 1,4,7,11,14,17-hexathiacycloeicosan-9,19-dione (diketo-20-ane-S6) has been synthesized and the crystal and molecular structure of the compound determined from a single-crystal X-ray study. The compound crystallizes in the monoclinic space group P21/c with two molecules per unit cell of dimensions a = 10.361(3) A, b = 9.370(3) A, c = 11.132(2) A, and β = 108.25(2)°. The observed and calculated densities are 1.37(1) and 1.35 g cm−3, respectively. Full-matrix least-squares refinement using 1342 unique reflections having 4° ≤ 2θ ≤ 50° and 1 ≥ 3[sgrave](I) converged at R = 0.039 and Rw = 0.049. The compound exists, in the crystalline state, in a conformation such that the sulfur atoms point away from the cavity of the ring, (exodentate), and the two ketone functionalities point above and below the plane of the ring, away from each other (anti), but toward the cavity of the ring (endodenrate).