Carbonyl Substitution in beta-Diketonatodicarbonyl-rhodium(I) by Cyclo-octadiene: Relationships with Experimental, Electronic and Calculated Parameters

Abstract

The substitution rate constant of the reaction between [Rh(β-diketonato)(CO)₂] and cyclo-octadiene is related to various empirical parameters and density functional theory calculated energies and charges, β-diketonato = R'COCHCOR. Results indicate that especially the Hammett meta substituent constants (σ), the Lever electronic parameters (EL) and the density functional theory calculated energies and charges predict the substitution rate constant to a high degree of accuracy, for example: In <i>k</i>₂=8.48 (σ_R+σ_R') - 2.24 (R²=0.99)=31.8 Σ<i>E</i>_L - 63.0 (R²=0.99)=-9.16 <i>E</i>_HOMO - 52.1 (R²=0.97)=101 ΣQ_Mulliken(Rh(CO)₂) - 49.9 (R² = 0.99).