Synthesis, NMR and properties of a novel crown ether dimer: X-ray molecular structure of bis (2, 5-dimethoxy-4,6-dimethyl-1,3-xylyl)-18-crown-4

The synthesis and complete characterization of the precursor diol 3 and that of the crown ether 4 are reported. Further the X-ray structure of this novel crown ether is included, which provide us with valuable information about its solid-state structure. The title molecule lies about a centre of symmetry. Thus the novel 18-membered macrocycle 4 has a symmetrical configuration. Interestingly, a side view of the molecule shows that the two methoxy groups on each ring are on the same side, face to face and bend over the two arene units in the macrocycle. Finally, preliminary studies of its complexing property towards rhodium cations are presented and discussed.