Adventitious formation of a new oxopentadienyl Mn(I) tricarbonyl complex: Structural study and bonding investigation of (η5-CH2C(Fc)CHC(Fc)O)Mn(CO)3

A Mn(I) tricarbonyl complex of a 1,3-diferrocenyl-1-oxopentadienyl ligand was synthesised adventitiously by what seems to be an in-situ aldol-like condensation of two acetylferrocene units promoted by benzyl-Mn(CO)5. X-ray structural analysis of this unexpected product confirms the η5 coordination of the 1,3-diferrocenyl-1-oxopentadienyl ligand to the Mn(CO)3 moiety. The nature of the metal-ligand bonding relationship was studied by theoretical calculations; it outlines the charge unbalance (polarisation) at the oxopentadienyl moiety as well as the lack of ketone character of the latter Mn-bound ligand.

The structure and bonding of a new oxopentadienyl complex of Mn(I) is reported.Figure optionsDownload as PowerPoint slideHighlights
► Reaction of acetylferrocene with PhCH2Mn(CO)5 was attempted.
► The oxopentadienyl product results from an aldol-type condensation.
► DFT and XRD investigations support a distorted η5 oxopentadienyl-Mn bonding mode.