Reactions of bis(silylcyclopentadienyl) tetracarbonyl diiron compounds [η^5-RC5H4Fe(CO)]2(μ-CO)2(R=SiMe3, 1; Si2Me5, 2) with HgCl2 resulted in cleavage of Fe-Fe bond and gave expected products 5-8, while from the corresponding reactions of bridged analogues R^1[η ^5-RC5H4Fe(CO)]2(μ-CO)2(R^1=SiMe2, 3; SiMe2OSiMe2, 4), unexpected products of disproportionation were isolated, as well as the expected ones. The occurrence of the disproportionation was investigated. All the products were characterized by IR, ^1H NMR and elemental analysis. The crystal structure of 5 was determined. The crystals of 5 are monoclinic, space group P2/1m with a=1.1648(3), b=0.7484(4), c=1.6823(5)nm and β=106.55(2)°, V=1.405(2)nm^3, Z=4, Dx=2.29g.cm^-^3.

Key words: INFRARED SPECTROPHOTOMETRY, ELEMENTAL ANALYSIS, CYCLOPENTADIENE P, IRON COMPLEX, DISPROPORTIONATION REACTION, PROTON MAGNETIC RESONANCE SPECTROMETRY, CARBONYL COMPOUNDS, MERCURY CHLORIDE