Iodomethane oxidative addition to β-diketonatobis(triphenylphosphite)rhodium(I) complexes: A synthetic, kinetic and computational study

Significance of the electron-density of molecular fragments on the properties of manganese(iii) β-diketonato complexes: an XPS and DFT study

“…53 For b-diketones and metal-bdiketonato complexes, the electronegativity of the b-diketonato ligands can conveniently be expressed in terms of Sc R , which is the sum of the Gordy scale group electronegativities, 24 of the different R groups attached to the b-diketonato ligands (RCOCHCOR 0 ) À . It has been shown that the relative electronwithdrawing or electron-donating ability of different R groups in b-diketone ligands as well as metal-b-diketonato complexes, inuences chemical properties like electrochemistry, 54,55 spectroscopic response, 56,57 kinetics, 58,59 turn-over frequency of catalysis, 60 and NMR peak positions 61 of the b-diketone ligands and metal-b-diketonato compounds. For [Mn III (RCOCHCOR 0 ) 3 ] complexes, the sum of the Gordy scale group electronegativities is Sc R ¼ 3(c R + c R 0 ).…”

Reactivity of [Rh(β-diketonato)(cod)] complexes: A DFT approach

“…These complexes can undergo a variety of substitutions, see Scheme 1 for selected reactions. For example: cod in [Rh(b-diketonato)(cod)] (cod ¼ 1,5-cyclooctadiene) can be replaced by two monodentate carbon monoxide ligands [16,17] (Scheme 1 reaction 1) or by two phosphite groups [18,19] (Scheme 1 reaction 2). Triphenyl phosphine can only substitute one CO in [Rh(b-diketonato)(CO) 2 ] [20] (Scheme 1 reaction 3) while triphenyl phosphite substitutes both CO groups [19,21] (Scheme 1 reaction 4).…”

“…For example: cod in [Rh(b-diketonato)(cod)] (cod ¼ 1,5-cyclooctadiene) can be replaced by two monodentate carbon monoxide ligands [16,17] (Scheme 1 reaction 1) or by two phosphite groups [18,19] (Scheme 1 reaction 2). Triphenyl phosphine can only substitute one CO in [Rh(b-diketonato)(CO) 2 ] [20] (Scheme 1 reaction 3) while triphenyl phosphite substitutes both CO groups [19,21] (Scheme 1 reaction 4). In contrast we observed that a series of derivatives of 1,10-phenanthroline (phen) or 2,2 0 -dipyridyl [22] reacts with the [Rh(b-diketonato)(cod)] with the replacement of the b-diketonato ligand (Scheme 1 reaction 5).…”

Prediction of chemical and electrochemical oxidation potentials of β-diketonatobis(triphenylphosphite)rhodium(I) complexes: A DFT study

“…Various parameters can be used to describe the electronic effect of the substituent groups R and R 0 of which the pK a of the free b-diketone and the Gordy scale group electronegativities (v R + v R 0 ) are often used [21,22,[37][38][39][40][41][42].…”

“…The reactivity of these rhodium complexes can experimentally be measured by means of the kinetic rate of oxidative addition of methyl iodide to [Rh(b-diketonato)(P(OPh) 3 ) 2 ] complexes, or by the electrochemical oxidation potential of the rhodium nucleus in [Rh(b-diketonato)(P(OPh) 3 ) 2 ]. Both the rate of oxidative addition [21] and the electrochemical oxidation potential [22] of [Rh(bdiketonato)(P(OPh) 3 ) 2 ] complexes are related to the electron density on the rhodium(I) centre as expressed by the sum of the group electronegativities of the b-diketonato side groups or the pK a of the uncoordinated b-diketone. This study focuses on theoretical ways to predict redox potentials and chemical reactivity.…”