First example of cyclodimerisation of a phospha-alkyne to a 1,3-diphosphacyclobutadiene. Syntheses of complexes of the type [M(η5-C5R5){η4-(ButCP)2}] R = H or Me; M = Co, Rh, or Ir): crystal and molecular structure of η5-pentamethylcyclopentadienyl-2,4-di-t-butyl-1,3-diphosphacyclobutadienecobalt(I), [Co(η5-C5Me5){η4-(ButCP)2}]

Abstract

Displacement of ethylene from [M(η⁵-C₅R₅)(C₂H₄)₂], (R = H, M = Co or Rh; R = Me, M = Co, Rh, or Ir) by treatment with Bu^tCP affords complexes containing the novel 2,4-di-t-butyl-1,3-diphosphacyclobutadiene ring.