Expedient Synthesis of a Metallostibine Os2(CO)8(µ‐SbPh): An Unusual and Strong Two‐Electron‐Donor Ligand

A metallostibine, Os2(CO)8(µ‐SbPh) (2), was generated readily and in high yield and purity from the Os3(CO)11(µ‐SbPh)(Cl)2 (1) cluster through elimination of the terminal Os(CO)3(Cl)2 Lewis acid fragment with activated γ‐alumina. Compound 2 is air sensitive in solution but relatively stable as a solid. The Sb atom in 2 adopts a trigonal pyramidal geometry in both the solid and solution states, with an active lone pair of electrons. Experimental and computational studies show that 2 is a strong two‐electron donor with a donor strength comparable to that of alkylphosphines. Strong two‐electron donor: The stable metallostibine Os2(CO)8(µ‐SbPh) can be obtained in high yield and purity through a one‐step reaction. Experimental and computational data show that its donor strength is comparable to that of alkylphosphines.