Metallafurans are a class of furans in which one CH unit is replaced by isolobal metal fragments. Mostly incorporating late transition metals or group 6 transition metals, however, planar group 4 or 5 metallafurans are rarely reported. And for the known examples of group 4 and 5 metallafurans, the five-membered metallacycles are considered to be four-electron π systems rather than six-electron, due to the exhaustion of metal electrons.<br/>Herein, we report the synthesis of a planar, six-π-electron α-tantallafuran by a one-pot process. Starting from a half-sandwich tantalum alkyl complex, both carbon monoxide and alkyne serve as building blocks to construct a planar TaC<sub>3</sub>O cycle across the metal center. Both the bulky carboranyl substituent and the bidentate phosphine ligand are believed to play a role in maintaining the planar ring conformation. Single crystal X-ray crystallographic analysis indicates a certain degree of bond length equalization over the metallacycle, as an evidence for electron delocalization. DFT study reveals the presence of π-interaction between the metal and the vinyl ketone fragment.

Tantallafuran supported by a linked cyclopentadienyl-carboranyl ligand: Synthesis and structure

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.