Synthesis and Structure Determination of the Linear Conjugated Polyynyl and Polyynediyl Iron Complexes Fp−(C⋮C) n −X (X = H (n = 1, 2); X = Fp (n = 1, 2, 4); Fp = (η5-C5Me5)Fe(CO)2)1

A series of polyynyl and polyynediyl complexes of iron, Fp*−(C⋮C) n −H [n = 2 (3)) and Fp*−(C⋮C) n −Fp* (n = 2 (4), 4 (5); Fp* = (η5-C5Me5)Fe(CO)2), have been prepared, and their linear structure has been confirmed by X-ray crystallography.