Thiophosphinoyl-Tethered Ylide-Substituted Heavier Carbenes: Synthesis, Structures and Stabilities

The synthesis and structure analysis of a series of mono and diylide-substituted tetrylenes of type YEX and Y₂ E (E=Ge, Sn, Pb; X=Cl or Br) using a thiophosphinoyl-tethered metallated ylide (Y=Ph₂ P(S)-C-P(pip)Ph₂ with pip=piperidyl) is reported, amongst the first ylide-substituted plumbylenes. The tetrylenes feature distinct trends in the spectroscopic and structural properties of the ylide ligand with increasing atomic number of the tetrel element. For instance, an increasingly high-field shifted signal for the thiophosphinoyl group is observed in the ³¹ P{¹ H} NMR spectrum as a consequence of the increasing polarity of the element-carbon bond, which likewise results in a shortening of the ylidic C-P bond in the solid-state structure. The diylidyltetrylenes are unstable towards transylidation forming the mono(ylide)tetrylenes when treated with the tetrel dihalides according to the stability trend: Y₂ Pb2 Sn2 Ge