New shapes of PC(sp³)P pincer complexes

Trans-chelating bis(diisopropylphosphino)triptycene (1) was employed as a platform for the construction of a new class of C(sp³)-metalated pincer complexes via C-H activation. We synthesized and fully characterized platinum(II), ruthenium(II), and iridium(HI) compounds bearing this tridentate ligand. In contrast to the known all-aliphatic C(sp³)-metalated compounds, the new complexes exhibit excellent thermal and conformational stability even under very harsh and noninert conditions, likely due to the lack of labile α- or β-hydrogens. In addition, the three-dimensional barrelene-based scaffold represents a unique structural motif for the design of PC(sp³)P-based compounds with unexplored steric and electronic features.