Since silicon-transition metal bond-containing compounds have important applications as catalyst, on the basis of our previous finding that the rearrangement reaction of (η⁵,η⁵-C₅H₄Me₂SiSiMe₂- C₅H₄)Fe₂(CO)₄ (1) through metathesis of Si—Si and Fe—Fe bonds provided an effective route to prepare Si—Fe bond-containing cyclic complex [Me₂Si-η⁵-C₅H₄Fe(CO)₂]₂ (2), the syntheses of PPh₃-substituted derivatives of the Si—Fe bonded cyclic structure, namely [Me₂Si-η⁵-C₅H₄Fe(CO)(PPh₃)][Me₂Si-η⁵-C₅H₄Fe- (CO)_2－n(PPh₃)_n] (3: n＝0 and 5: n＝1), were studied in the present paper. It was found that the metathetical rearrangement reaction of 1 in the presence of PPh₃ was the preferred method for preparing the mono-PPh₃ substituted complex 3, while the bis-PPh₃ substituted prod-uct 5 might be obtained through CO substitution of 3 for PPh₃ under photo-chemical conditions, and the cis and trans isomers of the product could be separated by preparative TLC. The molecular structure of 3 has been determined by the X-ray diffraction method. The influences on the molecular structure by PPh₃ substitution as well as the stability of the PPh₃ to Fe coordination bond were examined.

Key words: carbonyl ligand, triphenylphosphine ligand, crystal structure, Si—Fe bond