Nacnac‐Cobalt‐Mediated P(4) Transformations

A comparison of P(4) activations mediated by low‐valent β‐diketiminato (L) cobalt complexes is presented. The formal Co(0) source [K(2)(L(3)Co)(2)(μ(2):η(1),η(1)‐N(2))] (1) reacts with P(4) to form a mixture of the monoanionic complexes [K(thf)(6)][(L(3)Co)(2)(μ(2):η(4),η(4)‐P(4))] (2) and [K(thf)(6)][(L(3)Co)(2)(μ(2):η(3),η(3)‐P(3))] (3). The analogue Co(I) precursor [L(3)Co(tol)] (4 a), however, selectively yields the corresponding neutral derivative [(L(3)Co)(2)(μ(2):η(4),η(4)‐P(4))] (5 a). Compound 5 a undergoes thermal P atom loss to form the unprecedented complex [(L(3)Co)(2)(μ(2):η(3),η(3)‐P(3))] (6). The products 2 and 3 can be obtained selectively by an one‐electron reduction of their neutral precursors 5 a and 6, respectively. The electrochemical behaviour of 2, 3, 5 a, and 6 is monitored by cyclic voltammetry and their magnetism is examined by SQUID measurements and the Evans method. The initial Co(I)‐mediated P(4) activation is not influenced by applying the structurally different ligands L(1) and L(2), which is proven by the formation of the isostructural products [(LCo)(2)(μ(2):η(4),η(4)‐P(4))] [L=L(3) (5 a), L(1) (5 b), L(2) (5 c)].