Formation of a Stable Dihydrido(alkyl)platinum(IV) Complex by Water Activation

Haskel, Ariel; Keinan, Ehud

doi:10.1021/om990588m

Cited by 44 publications

(45 citation statements)

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“…The structure of B is supported by related reports [31,32] and by our previous observation that 1 is quantitatively converted into 6 under acidic conditions. [20] Possible reaction pathways: Scheme 2 presents three possible pathways for the formation of a s-CH 4 intermediate from B. One could envision that B, which bears two acidic protons, could lead to the s-methane complexes C or D via transition state TSA C H T U N G T R E N N U N G (B-C) or TSA C H T U N G T R E N N U N G (B-D).…”

Section: Resultsmentioning

confidence: 99%

“…Sephadex LH-20 (Fluka) was used to separate charged species. Tetramethylammonium triflate (Me 4 NOTf), [45] which was used as an internal standard in NMR reactions, and compounds 1, [46] 3, [47] 4, [21] 5, [48] and 6 [20] were prepared according to literature methods.…”

Section: Discussionmentioning

confidence: 99%

“…13 CO 2 was observed in the 13 C{ 1 H} NMR spectra recorded during the reaction of 13 CO-labelled 1. [20] Although this was found to be a downhill process, the large barrier to TSA C H T U N G T R E N N U N G (B 2 -D) precludes this route. However, complex G can also be reached starting from E 1 .…”

Section: N Ormentioning

confidence: 99%

“…[20,21] We attributed the thermal stability of 2 to the rigidity of the Tp ligand which prevents trans coordination of two pyrazolyl rings. [22] The transitory formation of a s-methane complex was supported by computational studies and by the observation that when 2 was dissolved in a deuterated protic solvent, such as [D 4 1 H NMR spectra of the reaction mixture, as well as 2 and its isotopologues.…”

Section: Introductionmentioning

confidence: 99%

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Proton Walk in the Aqueous Platinum Complex [TpPtMeCO] via a Sticky σ‐Methane Ligand

Lo¹,

Iron²,

Martin³

et al. 2007

Chemistry A European J

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Both experimental and theoretical evidence suggest that the proton exchange between water and the methyl group in [TpPt(CO)CH(3)] (1, Tp=hydridotripyrazolylborate) involves the formation and deprotonation of a "sticky" sigma-methane ligand. The efficiency of this nontrivial process has been attributed to the spatial orientation of functional groups that operate in concert to activate a water molecule and then achieve a multistep proton walk from water to an uncoordinated pyrazolyl nitrogen atom, to the methyl ligand, and then back to the nitrogen atom and water. The overall proton-exchange process has been proposed to involve an initial attack of water at the CO ligand in 1 with concerted deprotonation by the uncoordinated pyrazolyl nitrogen atom. The pyrazolium proton is then transferred to the Pt--CH(3) bond, leading to a sigma-methane intermediate. Subsequent rotation and deprotonation of the sigma-methane ligand, followed by reformation of 1 and water, result in scrambling of the methyl protons with the hydrogen atoms of water. An alternative two-step process that involves oxidative addition and reductive elimination has also been considered. The two competing mechanistic routes from 1 into [D(3)]-1, as well as the conversion of 1 into [TpPt(CH(3))H(2)] (2), have been examined by density functional theory (DFT) using a variety of exchange-correlation methods, primarily PW6B95, which was recently shown to be highly accurate for evaluating reactions of late-transition-metal complexes. The key role played by the free pyrazolyl nitrogen atom, acting as a proton carrier that abstracts a proton from water and transfers the proton to the Pt--CH(3) bond, is reminiscent of the dual functionality of histidine in the catalytic triad of natural serine proteases.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: N Ormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Proton Walk in the Aqueous Platinum Complex [TpPtMeCO] via a Sticky σ‐Methane Ligand

Lo¹,

Iron²,

Martin³

et al. 2007

Chemistry A European J

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“…Complexes of platinum(II) with a CO, an alkyl (or aryl) ligand and a tridentate N-donor ligand in the coordination sphere are not common and the most studied species are probably neutral scorpionate-based complexes having general formula Pt(R)(Tp)(CO) [27].…”

Section: Reactivity With Comentioning

confidence: 99%

New platinum(II) and palladium(II) quinoline-imine-pyridine, quinoline-imine-thiazole and quinoline-imine-imidazole complexes by metal-assisted condensation reactions

Bortoluzzi

Paolucci

Pitteri

et al. 2011

Journal of Organometallic Chemistry

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Platinum: Organometallic ChemistryBased in part on the article Platinum: Organometallic Chemistry by Charles M. Lukehart which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

Chen

2005

Encyclopedia of Inorganic Chemistry

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This article aims to describe the prominent advances of organoplatinum chemistry in the latest decade. Recent development in this field has been much advanced with the design of new ancillary ligands as well as new organic ligands. For the former, the polydentate cyclometallated ligands, tridentate pincer ligands, nitrogen‐donor ligands, and aminocarbenes are discussed. For the latter, in addition to the synthesis and structure of new organoplatinum compounds, a noteworthy growth is to exploit some of these compounds for luminescent materials. The content in this regard is brief since it has been covered as an independent article of this volume. Organoplatinum species with unprecedented bonding modes or new organometallic functionalities are discussed separately. The progress of nano sciences prompts the conceptual revolution in the whole frontier line of chemical research. Organoplatinum chemistry has been contributing in a profound way to construction of the new substances of large skeletons. Exploration starting from clusters and molecular assemblies to organometallic polymers, particularly with rational design, is addressed. Reactions involving the SiH, SiSi, CH, and CC bond formation or cleavage are crucial to hydrosilylation and alkane functionalization respectively. Platinum‐silylene chemistry accounts for a major breakthrough in synthetic chemistry. As to platinum‐hydrides that are mainly concerned in Pt(IV)‐state and are key intermediates in alkane activation, their syntheses and structures are discussed in Section 5. Platinum(IV)‐alkyls are the theme of Section 6. The reaction mechanisms of Pt(II)/Pt(IV) involving aqueous CH activation and other reactions or catalysis involving organoplatinum are summarized at the end.

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Formation of a Stable Dihydrido(alkyl)platinum(IV) Complex by Water Activation

Cited by 44 publications

References 45 publications

Proton Walk in the Aqueous Platinum Complex [TpPtMeCO] via a Sticky σ‐Methane Ligand

Proton Walk in the Aqueous Platinum Complex [TpPtMeCO] via a Sticky σ‐Methane Ligand

New platinum(II) and palladium(II) quinoline-imine-pyridine, quinoline-imine-thiazole and quinoline-imine-imidazole complexes by metal-assisted condensation reactions

Platinum: Organometallic ChemistryBased in part on the article Platinum: Organometallic Chemistry by Charles M. Lukehart which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

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