Geometry of Coordinatively Unsaturated Two-Legged Piano Stool Complexes with 16 Valence Electrons: A Theoretical Study†

摘要: The structure of coordinatively unsaturated (16-electron) two-legged piano stool complexes is analyzed with the extended Huckel methodology as well density functional theory. Pyramidal, and thus potentially chiral at metal, geometries are predicted to be preferred for bearing ligands like CO, CS, or NO+, containing low-lying π-acceptor orbitals, in case electropositive strong σ donors, e.g., silyl ligands. In all cases, however, computed inversion barriers low (<15 kcal mol-1). A minimum was located an η2-coordination acyl ligand [CpFe(acyl)NO]+, which may account stereospecific substitution acyl-containing systems. ground-state geometry isoelectronic series [(ηn-CnHn)M(CO)2] (M = Fe, Mn, Cr, V; n 4−7) probed a function ring size metal center.