STEREOCHEMISTRY OF 16-MEMBERED AZOCROWN AND AZOXYCROWN ETHERS - STRUCTURES OF THEIR SANDWICH POTASSIUM-IODIDE COMPLEXES

16-Membered dibenzoazo- and dibenzoazoxycrown ethers have been synthes ized. The Z and E isomers of the azocrown compound have been separated and the geometry of the -N=N- and -N(O)=N- groups determined. Potassi um iodide complexes of the azo-and azoxycrown ethers were obtained and their structures were determined by the X-ray method. The crystal of the azocrown ether complex is triclinic, space group P (1) over bar, a = 21.071(5), b = 12.112(4), c = 8.757(2) Angstrom; alpha = 81.28(2), beta = 84.66(2), gamma = 107.49(2)degrees. The azoxycrown ether comple x is monoclinic, space group C2/c, a = 15.648(3), b = 19.597(4), c = 1 4.651(3) Angstrom; beta = 111.30(3).