Synthesis of the Novel μ‐(Phosphanoalkylidene) Complexes [Fe 2 Cp 2 (CO) 2 (μ‐CO){μ‐C(CN)PR 2 }] (PR 2 = PEt 2 , PHCy, PHPh) and Molecular Structure of the PEt 2 Derivative

Replacement of SMe 2 at the pseudo‐alkylidyne μ‐carbon atom of [Fe 2 Cp 2 (CO) 2 (μ‐CO){μ‐C(CN)SMe 2 }]SO 3 CF 3 by PR 2 H (PR 2 = PEt 2 , PCyH, PPhH) results in the formation of the phosphonium salts [Fe 2 Cp 2 (CO) 2 (μ‐CO){μ‐C(CN)PHR 2 }]SO 3 CF 3 which upon deprotonation with NEt 3 yield the corresponding neutral complexes [Fe 2 Cp 2 (CO) 2 (μ‐CO){μ‐C(CN)PR 2 }]. These μ‐(phosphanoalkylidene) complexes have been characterized on the basis of IR, 31 P{ 1 H}‐, 1 H‐, and 13 C{ 1 H}‐NMR spectra and by the X‐ray molecular structure of [Fe 2 Cp 2 (CO) 2 (μ‐CO){μ‐C(CN)PEt 2 }].