Synthesis and characterization of new perchlorothiophene derivatives of some metals and metalloids

A short review is presented on lithium-hydrogen and lithium-halogen exchange reactions involving thiophene and several of its derivatives. Halogenated thiophenes required as starting materials were prepared in excellent yields by a slight modification of the method described by Ayres; perhalobithienyls were obtained using the coupling procedure of Cohen originally devised for perfluorobiphenyl syntheses. starting from 2,5-dichloro-3,4-diiodothiophene a stepwise synthesis was achieved of eleven heterocyclic thiophene derivatives containing sulphur, selenium, tellurium, phosphorus, arsenic, antimony, bismuth, silicon, tin or mercury as the heteroatoms. [Continues.]