Cyclopropenylidenetransition metal complexes: synthesis and structure of cis-dichloro(tri-n-butylphosphine)(bis(N,N-dimethylamino)cyclopropenylid ene)-palladium(II)

The synthesis of cis-dichloro(tri-n-butylphosphine)(bis(N,N-dimethylamino)-cyclopropenyli dene)palladium(II), cis-PdCl₂[C(Me₂NC)₂](P-n-Bu₃ ), from the reaction of [PdCl₂(C(Me₂NC)₂)]₂ with P-n-Bu₃ is described. The first precise analysis of the structure of a cyclopropenylidene-transition metal complex has been carried out. The C₃-ring is bound through the unique carbon atom to the metal center with a PdC distance of 1.961(3)Å and is roughly perpendicular to the metal square plane. All CC ring distances are equivalent within experimental error and average 1.383(2)Å. The dimethylamino groups are sp₂ hybridized at the nitrogen atoms and are coplanar with the carbbocyclic fragment. The compound crystallizes in the monoclinic space group C⁵_2h-P2₁/c with four molecules in a cell of dimensions a 7.933(4), b 15.524(6), c 19.572(7)Å, β 101.05(2)°, V 2326ų (T-160°C). The final values of R and R_w for the 226 variables and 4383 significant observations are 0.036 and 0.042. Characteristic spectroscopic (IR and NMR) data for the compound are reported.