An unsupported transition metal--lanthanide bond; synthesis and crystal structure of an Nd--Fe amido N-heterocyclic carbene complex.

A salt-elimination reaction between the neodymium monoiodide Nd(L')(N'')(I) [L' = Bu(t)NCH(2)CH(2){C(NCSiMe(3)CHNBu(t))}; N'' = N(SiMe(3))(2)] and K[FeCp(CO)(2)] affords the first complex with an unsupported 4f-3d metal-metal bond that is sufficiently stable to be isolated; the bond is identified as principally ionic in nature by DFT calculations.