Synthesis and cyclic voltammetry of some new metal carbene substituted cyclopentadienyliron half sandwich complexes

The syntheses of a number of cyclopentadienylcarbene iron half sandwich complexes are described. In addition to their spectroscopic characterization an X-ray crystal structure analysis is provided. The complexes prepared include chromium, molybdenum, and tungsten carbene complexes. The dicarbonyliron unit is substituted by benzyl, butyl or trimethylsilylmethyl groups. In two cases tetrametallic dimeric complexes connected by a propyl chain are presented. The reaction of the formylcyclopentadienyliron complex with a chromium carbene complex provided a vinylogous representative. Cyclic voltammetry was performed, and the data obtained are discussed in comparison to similar ferrocene based complexes.