Synthesis, Characterisation, Mossbauer Spectra, And Structures Of Some Trinuclear Iron-Tin Clusters

Reactions of [Fe-3(CO)(12)] with diaryltin species SnR(2) (R(1) = 2,4,8-triisopropylphenyl, R(2) = 2,6-diethylphenyl, R(3) = pentamethylphenyl) and with Sn[CH(PPh(2))(2)](2) have been investigated. The tin reagents SnR(2) (R = R(1) or R(2)) reacted under mild conditions to give in moderate yields the trinuclear species [Fe-2(CO)(8)(mu-SnR(2)(1))] 1 or [Fe-2(CO)(8)(mu SnR(2)(2))] 2, as orange-red crystalline solids, which decompose in air on prolonged exposure. The compound [Fe-2(CO)(8)(mu-SnR(2)(4))] 3 (R(4) = 2,4,6-triphenylphenyl) can be similarly obtained. Prolonged treatment of the carbonyl with the novel tin reagent SnR(2)(3), by contrast, afforded the known compound spiro-[(OC)(8)Fe2SnFe2(CO)(8)] 4 for which data are briefly reported. Reactions with tin or lead reagents M[CH(PPh(2))(2)](2) (M = Sn or Pb) afforded [Fe-2(CO)(6)(mu-CO)(mu-dppm)][dppm = 1,2-bis(diphenylphosphino)methane] rapidly and almost quantitatively. Full crystal and molecular structural data are reported for [Fe-2(CO)(8)(mu-SnR(2)(1))] and [Fe-2(CO)(8)(mu-SnR(2)(2))]. Mossbauer data are also presented for compounds 1-3, and interpreted in terms of the structural data for these and other systems.