Scalar Coupling Across [CH⋅⋅⋅FC] Interactions in (σ‐Aryl)‐Chelating Post‐Metallocenes

The nature and importance of CH⋅⋅⋅FC interactions is a topical yet controversial issue, and the development of spectroscopic methods to probe such contacts is therefore warranted. A series of Group 4 bis(benzyl) complexes supported by (σ‐aryl)‐2‐phenolate‐6‐pyridyl [O,C,NR 1 ] ligands bearing a fluorinated R 1 group (CF 3 or F) in the vicinity of the metal has been prepared. The X‐ray crystal structure of the CF 3 ‐substituted Hf derivative features intramolecular C‐H⋅⋅⋅F‐C and Hf⋅⋅⋅F‐C contacts. All complexes have been characterized by multinuclear NMR spectroscopy. The 1 H and 13 C NMR spectra of [M(O,C,NCF 3 )(CH 2 Ph) 2 ] derivatives display coupling (assigned to 1h J HF and 2h J CF for Ti; 3 J HF and 2 J CF (through M⋅⋅⋅F) for Hf and Zr) between the benzyl CH 2 and CF 3 moieties. [ 1 H, 19 F]‐HMBC NMR experiments have been performed for the M‐[O,C,N‐R 1 ] complexes and their [O,N,C] counterparts, revealing significant scalar coupling across the CH⋅⋅⋅FC interactions for Ti‐[O,C,N] and [O,N,C] species.