Synthesis and structure of a series of unique cobalt phosphides

Abstract

The reaction of CoCl₂ and [CoCl(PMe₃)₃] with the phosphidophosphine LiP(CH₂CH₂PMe₂)₂ afforded a unique class of cobalt phosphido complexes, revealing a new mode of reactivity for this ligand. The solid-state structure of the first monomeric cobalt phosphido complex, [Co{P(CH₂CH₂PMe₂)₂}{[P(CH₂CH₂PMe₂)₂]₂}]1 has been determined: monoclinic, space group P2₁/c, a= 15.484(7), b= 13.947(6), c= 17 875(2)Å, β= 108.54(2)°. An analogue, [CO{P(CH₂CH₂PMe₂)₂}(Me₂PCH₂CH₂PMe₂)]2, has been characterised by ³¹P-{¹H} NMR spectroscopy. Complex 1 was shown to be fluxional in solution and further characterised by two-dimensional correlation ³¹P-{¹H} NMR spectroscopy. The corresponding spectrum of 2 interestingly shows no ²J(P–P) coupling viathe cobalt centre.