Facile interconversion of mesitylcopper into a CuMes-Cu 2 bis(amidinate) triangle and a tetracuprous Möbius strip.

A new flexible bis(amidine) ligand featuring two additional N-donor groups incorporates a defined [Cu I MesCu 2 I ] 2+ fragment from mesitylcopper into a triangular cluster with a reactive organometallic coordination site. Subtle changes to the reaction protocol result in the formation of an intertwined tetracuprous arrangement that adopts the shape of a Möbius strip.