MOLECULAR-STRUCTURE AND CONFORMATION OF 2 ACYCLIC POLYTHIOETHERS - IMPLICATIONS FOR THE DESIGN OF HEAVY-METAL CHELATORS

The crystal structures of the 1, 9-bis(p-tolyl)-2,5,8-trithianonane (1) and 1,12-bis(p-tolyl)-2,5,8, 11-tetrathiadodecane (2) are reported. Previous studies of macrocyclic polythioethers have revealed a pronounced tendency for backbone CS-CC bonds to adopt gauche torsion angles. The same tendency is observed in the homologous acyclic polythioethers 1 and 2, demonstrating that the gauche preference is not simply the result of a macrocyclic constraint. Because of this gauche preference of CS-CC torsion units and the well-established anti preference of SC-CS torsion units, polythioethers constructed from ethylene sulfide subunits are generally far from “preorganized” for metal ion chelation. © 1990, American Chemical Society. All rights reserved.