NEW SUPRAMOLECULAR ARRAYS BASED ON INTERACTIONS BETWEEN CARBOXYLATE AND UREA GROUPS - SOLID-STATE AND SOLUTION BEHAVIOR

The urea-carboxylate interaction is introduced as a potentially genera l motif for the control of solid-state packing patterns. We show that simple phenylurea carboxylate derivatives can form extended hydrogen-b onded ribbons in the crystal in which the zig-zag shape of the aggrega te is controlled by the relative orientation of the two substituents a bout the phenyl core. We also show that an alternative type of aggrega tion may occur in solution involving the formation of cyclic aggregate s. Again, the size and stability of the aggregate is dependent on the substitution pattern of the monomer.