Iodomethane oxidative addition and CO migratory insertion in monocarbonylphosphine complexes of the type [Rh((C6H5)COCHCO((CH2)nCH3))(CO)(PPh3)]: Steric and electronic effects

Stuurman, Nomampondomise F.; Conradie, Jeanet

doi:10.1016/j.jorganchem.2008.10.040

Cited by 42 publications

(22 citation statements)

References 24 publications

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“…The 1 H and 31 P NMR spectra were recorded on a Bruker Avance DRX 250 or 400 MHz spectrometer in CDCl 3 as solvent. The operating frequencies and references, respectively, are shown in parentheses as follows: 1 H (250 or 400 MHz, TMS) and 31 (Mo Kα = 0.71073 Å). The cell parameters were retrieved using X-AREA [17] software and refined using X-AREA on all observed reflections.…”

Section: General Remarksmentioning

confidence: 99%

Phenylpyrazolate cycloplatinated(II) complexes: Kinetics of oxidation to Pt(IV) complexes

Nahaei

Rasekh

Rashidi

et al. 2016

Journal of Organometallic Chemistry

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The cycloplatinated(II) complex [PtMe(phpz)(DMSO)], 1, in which DMSO is dimethylsulphoxide and phpz is 1-phenylpyrazolate was synthesized by reaction of phpzH (1-phenylpyrazole) with the known complex [PtMe 2 (DMSO) 2 ]. The C^N cycloplatinated(II) complexes [PtMe(phpz)(L)], 2, where L = PPh 3 (2a), PPh 2 Me (2b) and P(OPh) 3 (2c), were synthesized by reaction of the complex 1 with the appropriate P donor ligands L. Reaction of the Pt(II) complexes 2 with MeI gave the cycloplatinated(IV) complexes [PtMe 2 I(C^N)(L)], where L = PPh 3 (3a), PPh 2 Me (3b) and P(OPh) 3 (3c). All the complexes were fully characterized using NMR spectroscopy and the Pt(II) complex 2a and the Pt(IV) complex 3a, both containing PPh 3 ligand, were further determined by X-ray crystallography. The cycloplatinated(II) complexes 2 have a metal-to-ligand charge-transfer band, which was used to easily follow the kinetics of their reactions with MeI. Rates of the reactions at different temperatures were measured and the large negative ΔS ‡ values were found in each reaction. The data were consistent with an associative S N 2 mechanism. The reactivity of Pt(II) complexes 2 towards oxidative addition was also theoretically investigated using DFT calculations, which were in agreement with experimental findings.

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Section: General Remarksmentioning

confidence: 99%

Phenylpyrazolate cycloplatinated(II) complexes: Kinetics of oxidation to Pt(IV) complexes

Nahaei

Rasekh

Rashidi

et al. 2016

Journal of Organometallic Chemistry

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“…The oxidative addition reaction of CH 3 I to [Ir 2 (m-Dcbp) (CO) 2 (PCy 3 ) 2 ] À was first explored on IR since this technique allow to distinguish between metal-CO bonds in M(I)-carbonyl (resonates at w1900e2000 cm À1 ), M(III)-alkyl (resonates at w2000e2100 cm À1 ) and M(III)-acyl (resonates at w1700e1750 cm À1 ) species, M ¼ metal such as Rh [29] or Ir [30]. Three reactions were observed on the IR.…”

Section: Infrared Studymentioning

confidence: 99%

“…A possible explanation for this negative activation entropy is the probable coordination of solvent molecules during the transition state formation. The rate of acyl formation (1.42 Â 10 À5 s À1 ) is clearly indicative of a complex which is deactivated towards CO insertion or methyl migration if compared to reaction rates of complexes such as [Rh(acac)(CO)(PPh 3 )] (1.6 Â 10 À3 s À1 ), [Rh(hpt)(CO)(PPh 3 )] (1.0 Â 10 À2 s À1 ) [32] (hpt ¼ thiohydroxamate anion) [18] and [Rh(tta)(CO)(PPh 3 )] (1.8 Â 10 À3 s À1 ) (tta ¼ 2-thenoyltrifluoroacetonato) [29]. The relative large K 2 values (Table 3) points to a situation where the equilibrium lies to the right and that k obs ¼ k 2 .…”

Section: Proposed Mechanistic Pathwaymentioning

confidence: 99%

A kinetic investigation of the oxidative addition reactions of the dimeric Bu4N[Ir2(μ-Dcbp)(CO)2(PCy3)2] complex with iodomethane

Grobbelaar¹,

Conradie²,

Venter³

et al. 2011

Journal of Organometallic Chemistry

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a b s t r a c tThe IR and UV/visible kinetic results of the oxidative addition of iodomethane to Bu 4 N[Ir 2 (m-Dcbp) (CO) 2 (PCy 3 ) 2 ] (Dcbp ¼ 3,5-dicarboxylatepyrazolate anion) showed three time separable reactions. The first, very fast reaction corresponds to the a Ir(I)eIr(III) alkyl species formation within 10 À3 s. The second, relative fast reaction corresponds to Ir(III)eIr(III) alkyl formation with a rate constant of 3.25(4) Â 10 À2 M À1 s À1 while the third and slowest reaction corresponds to Ir(III)eIr(III) acyl formation with a rate constant of 1.42 Â 10 À5 s À1 . The IR data clearly show the existence of a number of equilibria with the formation of an Ir (I)eIr(III) alkyl product which then react to form the Ir(III)eIr(III) which then slowly react to form the Ir(III)eIr(III) acyl product. A solvent study indicated increased oxidative addition activity in the presence of polar solvents, which is indicative of a polar transition state. The large negative entropy of activation for the Ir(III)eIr(III) alkyl formation step (k 2 ) of À178(23) JK À1 mol À1 is indicative of an associative process. DFT calculations successfully identified the stereochemistry of the starting complex, [Ir 2 (m-Dcbp)(CO) 2 (PCy 3 ) 2 ] À as well as that of the Ir-alkyl and acyl isomers. A reaction pathway, using the IR data and DFT calculations, is proposed for the reaction.

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“…Oxidative addition of methyl iodide to rhodium(I) b-diketonato complexes also leads to the formation of a stable rhodium(III) alkyl intermediate or reaction product [11][12][13][14][15][16][17][18][19]. A theoretical study of the oxidative addition of iodomethane to [Rh(CH 3 COCHC-OCH 3 )(P(OPh) 3 ) 2 ] [20] indicates that oxidative addition of iodo methane to [Rh(b-diketonato)(P(OPh) 3 ) 2 ] occurs via a two-step mechanism.…”

Section: Introductionmentioning

confidence: 99%

Iodomethane oxidative addition and CO migratory insertion in monocarbonylphosphine complexes of the type [Rh((C6H5)COCHCO((CH2)nCH3))(CO)(PPh3)]: Steric and electronic effects

Cited by 42 publications

References 24 publications

Phenylpyrazolate cycloplatinated(II) complexes: Kinetics of oxidation to Pt(IV) complexes

Phenylpyrazolate cycloplatinated(II) complexes: Kinetics of oxidation to Pt(IV) complexes

A kinetic investigation of the oxidative addition reactions of the dimeric Bu4N[Ir2(μ-Dcbp)(CO)2(PCy3)2] complex with iodomethane

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

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