Pentabenzylcyclopentadienylthallium( I ): Synthesis and Structure of a “Dimeric” Organothallium Compound with TlTl Interaction

A protective shield consisting of six benzyl groups envelops a Tl 1 Tl 1 unit in the title compound. The Tl–Tl distance of 3.6 Å does not correspond to that of a normal single bond but does indicate a bonding interaction—perhaps similar to that in Cu 1 Cu 1 and Au 1 Au 1 complexes. Normally, cyclopentadienylthallium complexes do not have a dimeric structure but rather a polymeric structure containing zigzag chains.