Coordination Behavior of [Cp″(2)Zr(µ(1:1)-As(4))] towards Lewis Acids

The functionalization of the arsenic transfer reagent [Cp″(2)Zr(η(1:1)-As(4))] (1) focuses on modifying its properties and enabling a broader scope of reactivity. The coordination behavior of 1 towards different Lewis-acidic transition metal complexes and main group compounds is investigated by experimental and computational studies. Depending on the steric requirements of the Lewis acids and the reaction temperature, a variety of new complexes with different coordination modes and coordination numbers could be synthesized. Depending on the Lewis acid (LA) used, a mono-substitution in [Cp″(2)Zr(µ,η(1:1:1:1)-As(4))(LA)] (LA = Fe(CO)(4) (4); B(C(6)F(5))(3) (7)) and [Cp″(2)Zr(µ,η(3:1:1)-As(4))(Fe(CO)(3))] (5) or a di-substitution [Cp″(2)Zr(µ(3),η(1:1:1:1)-As(4))(LA)(2)] (LA = W(CO)(5) (2); CpMn(CO)(2) (3); AlR(3) (6, R = Me, Et, (i)Bu)) are monitored. In contrast to other coordination products, 5 shows an η(3) coordination in which the butterfly As(4) ligand is rearranged to a cyclo-As(4) ligand. The reported complexes are rationalized in terms of inverse coordination.