SYNTHESIS AND CRYSTAL-STRUCTURE OF CYCLOTRIS-(4,4'-THIODIPHENYLENE KETONE)

The side reaction of macrocyclization that occurs during the synthesis of poly-(1,4-phenylenesulfide ketone) by polycondensation of a 4,4'-d ihalobenzophenone with sodium sulfide was studied. It was found that t he major product of this reaction is a cyclic trimer, cyclotris-(4,4'- thiodiphenylene ketone) (1). Despite the fact that ketone bridges are more rigid than sulfide bridges, the yield of the macrocycle is rather high, as it is in the synthesis of poly-(1,4-phenylenesulfide), and r eaches 20% under high dilution conditions. The structure of 1 was inve stigated by X-ray diffraction analysis (R = 0.069 on 3138 reflections) . Macrocycle 1 is strongly flattened in the crystal; the conformation observed is determined by the packing, since stereochemical analysis i ndicates high flexibility of the macrocycle. The solvate acetone molec ules incorporated in the crystal are disordered, nevertheless, they ar e strongly fixed in the cavities and channels of the crystal structure .