Electronic response of a (P,N)-based ligand on metal coordination.

The reaction of [(THF)Li(Ph(2)PC(H)Py)] with ZnCl(2) in the presence of ZnO yields the zinc complex [Zn(3)(Ph(2)PC(H)Py)(4)O] (1). Deprotonation of the phosphane Ph(2)P(CH(2)Py) with [Fe(N(SiMe(3))(2))2] gives the iron complexes [(Ph(2)P(CH(2)Py))Fe(Ph(2)PC(H)Py)2] (2) and [Fe(Ph(2)PC(H)Py)(N(SiMe(3))(2))]2 (3), depending on the ratio of phosphane. The solid state structures of the metal complexes illustrate the coordination flexibility of the [Ph(2)C(H)Py](-)-anion. Depending on the electronic requirements of the coordinated metal the anion acts as a (P,N)-chelating amide or C-coordinating carbanion with the P- and N-heteroatoms as donor bases.

Metal coordination to the formal P=N bond of an iminophosphorane and charge-density evidence against hypervalent phosphorus(V).

The iminophosphorane Ph(2)P(CH(2)Py)(NSiMe(3)) (1) was treated with deprotonating alkali metal reagents to give [(Et(2)O)Li[Ph(2)P(CHPy)(NSiMe(3))]] (2), [[Ph(2)P(CH(2)Py)(NSiMe(3))]Li[Ph(2)P(CHPy)(NSiMe(3))]] (3) and [[Ph(2)P(CH(2)Py)(NSiMe(3))]Na[Ph(2)P(CHPy)(NSiMe(3))]] (4). We report their coordination behaviour in solid-state structures and NMR spectroscopic features in solution. Furthermore, we furnish experimental evidence against hypervalency of the phosphorus atom in iminophosphoranes from experimental charge-density studies and subsequent topological analysis. The topological properties, correlated to the results from NMR spectroscopic investigations, illustrate that the formal P=N double bond is better written as a polar P(+)--N(-) single bond. Additionally, the effects of metal coordination on the bonding parameters of the iminophosphorane and the related anion are discussed.