Design of alkyl- and haloalkyl complexes of dimethylplatinum(IV) via oxidative addition: Reactivity, characterization and crystal structures

Momeni, Badri Z.; Hadi, Saba; Biglari, Abbas

doi:10.1016/j.ica.2016.10.029

Cited by 7 publications

(6 citation statements)

References 39 publications

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“…36 It contrasts to a recent report on the OA of benzyl bromide to [Pt(N^N)(Me) 2 ] (N^N = 5Me 2 bpy or phen) 35 with the main product showing the two Me groups in the equatorial positions (like 2a) and one minor species with one Me ligand trans to Br in the axial positions. 35 Experimental Reductive Elimination Reaction of 2a. Heating complex 2a at 70 °C in toluene for 4 days gave quantitatively the Pt(II) complex [Pt(pbt)Br(CH 2 Ph)] in its stereoisomeric form 3a (Figure 1, Chart 2, and Figure S4, Supporting Information).…”

Section: ■ Results and Discussioncontrasting

confidence: 70%

“…Products with two C ligands in the axial positions ( mer -PtC 3 ) were not observed . Two fac -PtC 3 isomers were also previously reported for the OA of benzyl bromide to the complexes [Pt(N^N)(Me) 2 ] bearing the symmetric ligands 5,5′-Me 2 -2,2′-bipyridine (5Me 2 bpy) or 1,10-phenanthroline (phen) with the main products having the benzyl ligand trans to Br in the axial positions (like 2a ) and the minor species with the Me ligand trans to Br in the axial positions (like 2a’ and 2a” ) …”

Section: Introductionmentioning

confidence: 61%

“…7 Two fac-PtC 3 isomers were also previously reported for the OA of benzyl bromide to the complexes [Pt(N^N)(Me) 2 ] bearing the symmetric ligands 5,5′-Me 2 -2,2′-bipyridine (5Me 2 bpy) or 1,10-phenanthroline (phen) with the main products having the benzyl ligand trans to Br in the axial positions (like 2a) and the minor species with the Me ligand trans to Br in the axial positions (like 2a' and 2a"). 35 Herein, we report on a study on the competitive C−C reductive elimination of Me−Me or benzyl−Me from the complex 2a experimentally and by density functional theory (DFT) calculations alongside the refined synthesis and 195 Pt nuclear magnetic resonance (NMR) characterization of 2a.…”

Section: ■ Introductionmentioning

confidence: 99%

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Cross-Coupling versus Homo-Coupling at a Pt(IV) Center: Computational and Experimental Approaches

et al. 2023

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C−C cross-coupling versus homo-coupling from the Pt(IV) complex [Pt(pbt)Br(CH 2 Ph)(Me) 2 ], 2a (pbt = 2-(2-pyridyl)benzothiazole), was studied experimentally and through density functional theory calculations. The calculations show that from the three competitive C−C reductive eliminations, (A) Me−Me homo-coupling, (B) benzyl−Me cross-coupling (Me trans to N py ), and (C) benzyl−Me cross-coupling (Me trans to N bz ), the Me−Me homo-coupling reaction is preferred over the other two due to the lower energy barrier of the Me−Me vs the benzyl−Me bond formation. The reaction is initiated by a dissociation of the Br − ligand followed by Me−Me homo-coupling from the resulting five-coordinate intermediate. Experimentally, complex 2a undergoes reductive elimination in toluene at 70 °C producing ethane and the Pt(II) complex [Pt(pbt)Br(CH 2 Ph)] 3a in over 99% yield, fully in line with the calculations. 1 H 195 Pt HMBC experiments allowed studying even sub-% products in this study.

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Section: ■ Results and Discussioncontrasting

confidence: 70%

Section: Introductionmentioning

confidence: 61%

Section: ■ Introductionmentioning

confidence: 99%

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Cross-Coupling versus Homo-Coupling at a Pt(IV) Center: Computational and Experimental Approaches

et al. 2023

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“…The 1 J (PtC) values (see Table ) are smaller than the corresponding values reported for the methyl groups of complex 1a ( 1 J (PtC) = 807 Hz and 844 Hz), confirming the oxidation of Pt(II) to Pt(IV) by benzyl bromide. The CH 2 of benzyl appears at δ = 22.8 and was confirmed by DEPT 13 C analysis …”

Section: Results and Discussionmentioning

confidence: 68%

“…The CH 2 of benzyl appears at δ = 22.8 and was confirmed by DEPT 13 C analysis. 63 2a′ also shows the two singlet resonances for two different methyl ligands being trans to N of the pyridyl ligand and Br. Similar to 2a, the isomer 2a′ displays a singlet C atom of CH 2 , which was confirmed by DEPT 13 C NMR experiments.…”

Section: ■ Introductionmentioning

confidence: 99%

Ligand-Mediated C–Br Oxidative Addition to Cycloplatinated(II) Complexes and Benzyl-Me C–C Bond Reductive Elimination from a Cycloplatinated(IV) Complex

et al. 2020

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Reaction of the Pt(II) complexes [PtMe2(pbt)], 1a, (pbt = 2-(2-pyridyl)benzothiazole) and [PtMe(C^N)(PPh2Me)] [C^N = deprotonated 2-phenylpyridine (ppy), 1b, or deprotonated benzo[h]quinoline (bhq), 1c] with benzyl bromide, PhCH2Br, is studied. The reaction of 1a with PhCH2Br gave the Pt(IV) product complex [PtBr(CH2Ph)Me2(pbt)]. The major trans isomer is formed in a trans oxidative addition (2a), while the minor cis products (2a′ and 2a″) resulted from an isomerization process. A solution of Pt(II) complex 1a in the presence of benzyl bromide in toluene at 70 °C after 7 days gradually gave the dibromo Pt(IV) complex [Pt(Br)2Me2(pbt)], 4a, as determined by NMR spectroscopy and single-crystal XRD. The reaction of complexes 1b and 1c with PhCH2Br gave the Pt(IV) complexes [PtMeBr(CH2Ph)(C^N)(PPh2Me)] (C^N = ppy; 2b; C^N = bhq, 2c), in which the phosphine and benzyl ligands are trans. Multinuclear NMR spectroscopy ruled out other isomers. Attempts to grow crystals of the cycloplatinated(IV) complex 2b yielded a previously reported Pt(II) complex [PtBr(ppy)(PPh2Me)], 3b, presumably from reductive elimination of ethylbenzene. UV–vis spectroscopy was used to study the kinetics of reaction of Pt(II) complexes 1a–1c with benzyl bromide. The data are consistent with a second-order SN2 mechanism and the first order in both the Pt complex and PhCH2Br. The rate of reaction decreases along the series 1a ≫ 1c > 1b. Density functional theory calculations were carried out to support experimental findings and understand the formation of isomers.

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Push-pull ligands to enhance the oxygen activation step in catalytic oxidation with platinum complexes

Abo-Amer

Boyle

Puddephatt

2018

Inorganica Chimica Acta

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Design of alkyl- and haloalkyl complexes of dimethylplatinum(IV) via oxidative addition: Reactivity, characterization and crystal structures

Cited by 7 publications

References 39 publications

Cross-Coupling versus Homo-Coupling at a Pt(IV) Center: Computational and Experimental Approaches

Cross-Coupling versus Homo-Coupling at a Pt(IV) Center: Computational and Experimental Approaches

Ligand-Mediated C–Br Oxidative Addition to Cycloplatinated(II) Complexes and Benzyl-Me C–C Bond Reductive Elimination from a Cycloplatinated(IV) Complex

Push-pull ligands to enhance the oxygen activation step in catalytic oxidation with platinum complexes

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