Palladium and platinum complexes of a benzannulated N-heterocyclic plumbylene with an unusual bonding mode

Reaction of the N,N'-diisobutyl-substituted benzannulated N-heterocyclic plumbylene (NHPb) 1 with [Pd(PPh(3))(4)] and [Pt(PPh(3))(4)] gave the complexes [M(NHPb)(PPh(3))(3)] (M = Pd [2], Pt [3]). X-ray diffraction studies of both complexes showed an angle of ~125° between the plumbylene plane and the transition-metal-Pb axis, indicating coordination of the transition metal to the empty π orbital of the plumbylene Pb atom. The experimentally determined metric parameters of complexes [2] and [3] are discussed on the basis of DFT calculations.