A DFT study of the reactivity of β-diketonato-1,5-cyclo-octadieneiridium(I) complexes

Good linear relationships exist between density functional theory (DFT) calculated orbital energies and charges of [Ir(β-diketonato)(cod)] complexes and the experimental second order substitution rate constant of the [Ir(R′COCHCOR)(cod)] + phen → [Ir(R′COCHCOR)(cod)(phen)] reaction. Both calculated and experimental values relate to the electron-donating and -withdrawing properties of the side groups R and R′ on the β-diketonato ligand (RCOCHCOR′)− as described by the Gordy scale group electronegativities, Hammett meta substituent constants, Lever electronic parameters and the pKa of the free β-diketone.

Relationships between kinetic rate constants, electronic parameters and DFT calculated orbital energies and charges of [Ir(β-diketonato)(cod)] complexes.Figure optionsDownload as PowerPoint slideHighlight
► [Ir(β-diketonato)(cod)] + 1,10-phenanthroline gives [Ir(β-diketonato)(cod)(phen)].
► Prediction of reactivity from DFT calculated, experimental and empirical values.
► EHOMO = -0.0619 ln k2 - 3.92, k2 = second-order substitution rate constant.