Theoretical investigation of the role of chelating biphosphine ligands in oxidative addition reactions of platinum complexes

Nabavizadeh, S. Masoud; Nikahd, Sahebeh; Hosseini, Fatemeh Niroomand

doi:10.1007/s13738-015-0661-5

Cited by 4 publications

(3 citation statements)

References 34 publications

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“…On the other hand, two elementary reactions, oxidative addition and reductive elimination, are very important because of their major role in many catalytic processes. − These reactions have been the subject of many studies, and organoplatinum(II) and -(IV) complexes have been used to investigate their chemistry in detail. − Most organoplatinum complexes used in this regard include N-donor (such as 2,2′-bipyridine) or cyclometalated (such as 2-phenylpyridinate) chelate ligands. − These organoplatinum(II) complexes having N^N or C^N ligands are highly reactive toward oxidative addition reactions, which typically proceed by an S N 2 mechanism, as has been confirmed experimentally − and computationally. − In contrast to many reports on the oxidative addition and reductive elimination of organoplatinum complexes bearing N^N or C^N chelate ligands, few studies have been reported on the reactivity of bis-NHC platinum complexes. ,− Bis-NHC chelate complexes of dimethylplatinum are rare. Jamali and co-workers prepared the complex [PtMe 2 (bis-NHC)] by the reaction of [PtMe 2 (μ-SMe 2 )] 2 with 1,1′-methylene-3,3′-bis[( N -( tert -butyl)imidazol-2-diylidene] in the presence of Ag 2 O .…”

Section: Introductionmentioning

confidence: 99%

Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

et al. 2021

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Three classes of Pt(II) complexes of the types [PtMe 2 (NHC)] (NHC = 1,1′-dimethyl-3,3′-methylenediimidazolin-2,2′-diylidene), [PtMe 2 (N^N)] (N^N = 2,2′-bipyridine, 1,10phenanthroline), and [PtMe(C^N)(SMe 2 )] (C^N = 2-phenylpyridinate, benzo[h]quinolinate), with a systematic variation in the chelating ligand, were chosen to investigate the oxidative addition of Pt(II) complexes with acetyl halides and the ensuing C−C reductive elimination from the corresponding Pt(IV) complexes.In accordance with the nature of the chelating ligand, the following conclusions can be ascertained: (i) in the reaction of [PtMe 2 (NHC)] complex 1a with acetyl halides, the order of the energy barriers (kcal/mol) for C−X bond activation is computed as Cl (24.4) ≈ Br (23.7) ≈ I (23.6), which are in a narrow range, showing no significant halide effect; (ii) while the energy barriers for oxidative addition of acetyl halides to complex 1a are almost the same, the C sp 3 −C sp 2 (CH 3 −COMe) reductive elimination barriers from [PtMe 2 (NHC)(MeCO)X] for X = Cl, Br, I are 23.5, 16.3, and 10.3 kcal/mol, respectively (lower than the acetyl halide oxidative addition to [PtMe 2 (NHC)]), suggesting that, when X = I, the Pt(IV) complex is more prone to undergo reductive elimination in comparison to the related Cl and Br analogues; (iii) the NHC Pt(IV) complexes selectively form C sp 3 −C sp 2 bonds instead of C sp 3 −C sp 3 bonds in reductive elimination; (iv) while NHC Pt(IV) complexes undergo a C−C reductive elimination process, the C−C coupling reaction is quite difficult for [PtCl(COMe)Me 2 (N^N)] complexes because of the high energy barrier found for C−C bond formation versus C−Cl oxidative addition; (v) similarly to NHC Pt(IV) complexes, the cycloplatinated (IV) complexes [PtCl(COMe)Me(C^N)(SMe 2 )] readily undergo C−C bond formation with reductive elimination.

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Section: Introductionmentioning

confidence: 99%

Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

et al. 2021

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“…[1,6,[19][20][21][22][23][24][25][26][27] This involves nucleophilic substitution of halide by Pt complex to form a Pt-C bond, followed by subsequent coordination of halide to form a six-coordinate octahedral alkyl product. It is interesting to compare the behaviours of RCH 2 Br (R = CH 3 , Ph and PhCH 2 ) in their oxidative addition reactions with the organoplatinum(II) complex 1a with an emphasis on the differences between the effect of the R group of alkyl halides.…”

Section: Dft Studymentioning

confidence: 99%

Reaction of dimethylplatinum(II) complexes with PhCH₂CH₂Br: Comparative reactivity with CH₃CH₂Br and PhCH₂Br and synthesis of Pt(IV) complexes

Sangari

Rashidi

Nabavizadeh

et al. 2017

Applied Organom Chemis

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Oxidative addition of 2-phenylethylbromide (PhCH 2 CH 2 Br) to dimethylplatinum(II) complexes [PtMe 2 (NN)] (1a, NN = 2,2′-bipyridine (bpy); 1b, NN = 1,10-phenanthroline (phen)) afforded the new organoplatinum(IV) complexes [PtMe 2 (Br)(PhCH 2 CH 2 )(bpy)], as a mixture of trans (2a) and cis (3a) isomers, and [PtMe 2 (Br)(PhCH 2 CH 2 )(phen)], as a mixture of trans (2b) and cis (3b) isomers, respectively. The new Pt(IV) complexes were readily characterized using multinuclear ( 1 H and 13 C) NMR spectroscopy and elemental microanalysis. The crystal structure of 2a was further determined using X-ray crystallography indicating an octahedral geometry around the platinum centre. A comparison of reactivity of RCH 2 Br reagents (R = CH 3 , Ph or PhCH 2 ) in their oxidative addition reactions with complex 1a, with an emphasis on the effects of the R groups of alkyl halides, was also conducted using density functional theory.

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“…On the other hand, oxidative addition reactions in catalytic processes have been well established. , Among transition metal complexes, cycloplatinated(II) complexes having ĈN ligands are highly reactive toward oxidative addition reactions, which typically proceed by an S N 2 mechanism as has been confirmed experimentally ,,− and computationally. , For example, MeI oxidative addition to a cyclometalated platinum(II) complex such as [PtMe(ĈN)PPh 3 ] (ĈN = 2-phenylpyridyinate or benzo[h]quinolate) gives the corresponding dimethylplatinum(IV) complex …”

Section: Introductionmentioning

confidence: 99%

Which is the Stronger Nucleophile, Platinum or Nitrogen in Rollover Cycloplatinated(II) Complexes?

2017

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The rollover cyclometalated platinum(II) complexes [PtMe(2,X'-bpy-H)(PPh)], (X = 2, 1a; X = 3, 1b; and X = 4, 1c) containing two potential nucleophilic centers have been investigated to elucidate which center is the stronger nucleophile toward methyl iodide. On the basis of DFT calculations, complexes 1b and 1c are predicted reacting with MeI through the free nitrogen donor to form N-methylated platinum(II) complexes, while complex 1a reacts through oxidative addition on platinum to give a platinum(IV) complex, which is in agreement with experimental findings. The reasons for this difference in selectivity for complexes 1a-1c are discussed based on the energy barrier needed for N-methylation versus oxidative addition reactions.

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Theoretical investigation of the role of chelating biphosphine ligands in oxidative addition reactions of platinum complexes

Cited by 4 publications

References 34 publications

Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Reaction of dimethylplatinum(II) complexes with PhCH₂CH₂Br: Comparative reactivity with CH₃CH₂Br and PhCH₂Br and synthesis of Pt(IV) complexes

Which is the Stronger Nucleophile, Platinum or Nitrogen in Rollover Cycloplatinated(II) Complexes?

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Theoretical investigation of the role of chelating biphosphine ligands in oxidative addition reactions of platinum complexes

Cited by 4 publications

References 34 publications

Selectivity in Competitive Csp2–Csp3 versus Csp3–Csp3 Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Selectivity in Competitive Csp2–Csp3 versus Csp3–Csp3 Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Reaction of dimethylplatinum(II) complexes with PhCH2CH2Br: Comparative reactivity with CH3CH2Br and PhCH2Br and synthesis of Pt(IV) complexes

Which is the Stronger Nucleophile, Platinum or Nitrogen in Rollover Cycloplatinated(II) Complexes?

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Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Selectivity in Competitive C_sp²–C_sp³ versus C_sp³–C_sp³ Reductive Eliminations at Pt(IV) Complexes: Experimental and Computational Approaches

Reaction of dimethylplatinum(II) complexes with PhCH₂CH₂Br: Comparative reactivity with CH₃CH₂Br and PhCH₂Br and synthesis of Pt(IV) complexes