Enthalpies of reaction of (benzylideneacetone)iron tricarbonyl, (BDA)Fe(CO)3, with phosphine ligands. Thermodynamic insights into iron chemistry

Article abstract of DOI:10.1021/om00046a063

The enthalpies of reaction of (BDA)Fe(CO)₃ (BDA = benzylideneacetone) with a series of monodentate phosphine ligands (PR₃) leading to the formation of trans-(PR₃)₂Fe(CO)₃ complexes have been measured by solution calorimetry in THF at 50°C. These enthalpy data help establish the following relative order of stability: PEt₃ > PⁿBu₃ > PMe₃ > PPhMe₂ > PPh₂Me > PPh₃. The data span a range of 15 kcal/mol. This stability scale sheds light on the relative donating ability of phosphines. These data also allow comparison with other organometallic systems and give insight into factors influencing the Fe-PR₃ bond disruption enthalpies in the (PR₃)₂Fe-(CO)₃ system.