One-step syntheses of Ph 3P-substituted selenido carbonyl iron and ruthenium clusters Part 2. Crystal structures of Fe 2(μ 2-Se 2)(CO) 6- n(PPh 3) n( n=1 or 2) Fe 3(μ 3-Se) 2(CO) 8(PPh 3) and Ru 4(μ 4-Se) 2(μ-CO) 2(CO) 8(PPh 3), and HPLC behaviour of the iron derivatives

Abstract

Ph 3PSe reacts with Fe 3(CO) 12 giving six products ( 1–6) belonging to three different families of clusters: Fe 3(μ-Se 2)(CO) 9- n L n (two products, 3,5, n = 1, 2, Fe 3( μ 3-Se) 2(CO) 9- n L n (three products, 1, 2, 4, n= 0–2) and Fe 3-Se)( μ- CO) 9- n L n (one product, 6, n = 2). Under the same conditions, Ru 3(CO) 12 affords Fe 3(μ 3-Se) 2(CO) 9- n (PPh 3) n (three products 7,8,10, n = 1–3) and the tetraruthenium clusters Ru 4(μ 4-Se) 4(CO) 2(CO) 9- n (PPh 3) n (two products, 11, 9, n=1,2). The structures of the clusters 2, 3, 5 and 11 · 1 2 CH 2Cl 2 have been determined by X-ray diffraction methods. The mass-spectral behaviour of iron mono- and disubstituted phosphine derivatives ( 2–6) is characterised by the low abundance (<6%) of polynuclear fragments, even under NICI conditions. Gas-phase rearrangements are considered to take place in order to explain the presence of certain peaks. The six iron derivatives are effectively separated by HPLC, the elution order depending on the degree of phosphine substitution and the kind of cluster framework.