A Diamagnetic Dititanium(III) Paddlewheel Complex with No Direct Metal−Metal Bond

Reaction of Ti[N(Bu t )Ar]3 (Ar = 3,5-C6H3Me2 or Ar‘ = C6H5) with CO2 at −40 °C produces diamagmetic TiIII paddlewheel complexes with long Ti−Ti separations (>3.4 Å), thus excluding direct Ti−Ti bonding. 1H NMR spectroscopy shows that the compounds are diamagnetic in solution in the temperature range of −65 to +70 °C. In the solid state, the diamagnetism was found to persist between 2 and 300 K. Calculations at the density functional theory level suggest that the diamagnetism results from antiferromagnetic coupling by superexchange through the ligand π system.