Investigation of Chemical Bonding in In Situ Cryocrystallized Organometallic Liquids

This report presents the crystal structure of organometallic complexes namely (a) (η4-1, 3 Cyclohexadiene) iron tricarbonyl [I] and (b) (Methyl cyclopentadienyl) manganese tricarbonyl [II] (both are liquid at the room temperature), which were determined using state-of-the-art in situ cryocrystallization technique. The bonding features are elucidated using topological analysis of charge density in the framework of Quantum Theory of Atoms in Molecules (QTAIM) and theoretical charge density analysis (multipolar refinement), to decipher the metal-carbonyl, metal-olefin and metal-carbocyclic ligand interactions in these complexes. Complex I displays the simultaneous interplay of 'synergic effect' (σ-donation and π-back bonding in metal and end-on-coordinated carbonyl interaction) as well as consistency with Dewar-Chatt-Duncanson (DCD) model (metal and side-on-coordinated π-ligand interaction).