Synthesis and Characterization of a Rhenanaphthalene Isomer.

Exploration of organometallic metallacycles has led to the development of various polycyclic compouds with fascinating structures, which could be used as functional materials. In this work, a new rhenanaphthalene isomer was isolated from the reaction of ReH5(PMe2Ph)3 with o-ethynylphenyl alkyne in the presence of excess HCl. Its structure was then identified using the single-crystal X-ray diffraction and NMR spectroscopy. DFT studies suggest that its formation involves two protonation reactions and two migration reactions. This new rhenanaphthalene isomer enriches the family of metallacycles.