The reaction of 1,2-bis(cyclohexylcyclopentadienyl) tetramethyldisilane with Fe(CO)5 in refluxing xylene afforded a mixture of cis and trans isomers of the diiron complex (MezSiSiM^tCc- CgHnCsI^FeCCCO^C^-CC)^ (2), which were separated by column chromatography. When the two isomers were heated in refluxing xylene, the cis substrate 2c rearranged to the trans product [Me2Si(c-C6HnC5H3) Fe(CO)2]2 (3t), while the trans substrate 2t to the cis product 3c. This indicates that the rearrangement reaction is stereospecific. Molecular structures of 3c and 4t were determined by X-ray diffraction analysis.

Key words: SILANE P;XRD;CRYSTAL STRUCTURE;REARRANGEMENT REACTION;IRON COMPOUNDS, SPECIFICITY