Synthesis, structure, and coordination properties of silicon-bridged macrocycles

The synthesis and characterization of silicon-bridged macrocyclic compounds are presented. The scheme involves the reaction of carbo- and heterocyclic dianions with bis-electrophiles. Silicalix(4)arene was formed when p-tert-butylmethoxybenzene has been used as starting material. X-ray crystallographic studies of sicalix(4)arene conformers showed a partial cone conformation. Tests also indicate that the macrocycles extract metal ions with less affinity compared to crown ethers.