Intermediates en Route Towards Tetranitrosyl‐bis(diorganophosphanido)diiron Complexes

The reaction of the coordinatively unsaturated complexes [Fe2(CO)5(μ‐PR2)(μ‐PR′2)] (1 a: R=R′=tBu; 1 b: R=tBu, R′=Cy) with nitric oxide was investigated in more detail. Thus, the novel complex [Fe2(CO)3(NO)2(μ‐PtBu2)2] (2) was obtained which can be seen as an intermediate on the way to the already described tetranitrosyl complex [Fe2(NO)4(μ‐PtBu2)2] (3 a). Compound 2 was characterized by spectroscopic means and its molecular structure was confirmed by single‐crystal X‐ray diffraction. An additional in situ IR measurement gave insight in the reaction pathway. In addition, the molecular structure of the known mixed phosphanido‐bridged species [Fe2(NO)4(μ‐PCy2)(μ‐PtBu2)] (3 b) was determined.