CRYSTAL-STRUCTURE OF 3 DIAZA-CROWNS-18

The crystal structures of three diaza crowns-18, namely 1,4,10,13-tetr aoxa-7,16-diazacyclooctadecane (crown 1), 1,4,10,13-tetraoxa-7, 16-dia zacyclooctadecane-7,16-diacetonitrile (crown 2) and -tetraoxa-7,16-dia zacyclooctadecane-7,16-diyldi-2, [4-methyl-benzenesulfonamide] (crown 3) have the following space groups and unit cell parameters: crown 1(C 12H26N2O4), monoclinic, P2(1)/c, Z = 2, a = 10.207(3) Angstrom, b = 8. 494(3) Angstrom, c = 8.942(3) Angstrom, beta = 109.39(3)degrees; crown 2(C16H28N4O4), triclinic, P (1) over bar, Z = 1, a = 6.226(3) Angstro m, b = 8.367(4) Angstrom, c = 9.323(4) Angstrom, alpha = 74.13(3)degre es, beta = 74.66(2)degrees, gamma = 81.56(2)degrees; and crown 3 (C30H 48N4O8S2), triclinic, P (1) over bar, Z = 1, a = 7.880(3) Angstrom, b = 10.559(4) Angstrom, c = 10.984(4) Angstrom, alpha = 72.63(3)degrees, beta = 77.67(3)degrees, gamma = 71.87(3)degrees. The structures were solved using direct methods and refined by full-matrix least-squares t echniques to R1 of 0.039, 0.045 and 0.055, respectively. Geometry of t he 18-membered ring of the crowns studied, in the neat state and engag ed in complexes with alkali metals, has been thoroughly examined in or der to reveal similarities and differences between them, relations bet ween constitution and ability to interaction, as well as possibilities of selective complexation of metal cations.