Synthesis and molecular structure of mixed-metal stannylene derivatives of cyclopentadienyl(nitrosyl)(carbonyl) manganese

The metathesis of CpMn(CO)(NO)SnCl3 (I) and anionic carbonyls (ML−) Mn(CO)5−, Co(CO)4−, Cp′Mo(CO)3−, Cp′W(CO)3−, Cp″Mo(CO)3− provided trinuclear mixed-metal complexes of general formula CpMn(CO)(NO)SnCl2ML (VIII–XII; Cp = C5H5, Cp′ = C5H4CH3, Cp″ = C5H3(C4H9)2). Along with XII, the product of transmetallation Cp″Mo(CO)3SnCl3 (XIII) was separated. Interaction of I with Fe2(CO)82− gave the mixed-metal cluster Cp(CO)(NO)Mn–SnCl2–Fe(CO)4–SnCl2–MnCp(CO)(NO) (XIV) which contain the pentanuclear metal-chain. As determined by the single crystal XRD analysis, the Mn–Sn distance in CpMn(CO)(NO)Sn fragment is 0.2 Å shorter than the expected value based on the Mn/Sn sum of covalent radii (SCR). From the other hand, the shortening of Sn–ML distances is in an accord with the donor ability of an ML fragment in the row Co(CO)4 ∼ Mn(CO)5 < Fe(CO)4 < CpMn(CO)(NO < Cp′Mo(CO)3 < Cp′W(CO)3 < Cp″Mo(CO)3 owing to the additive back donation of the transition metal d-LEP to Sn vacant orbitals. The absence of substantial elongation of the Sn–Cl distances may result from the π-back donation of transition metal d-orbitals to tin d-orbitals.