A hydrogen atom in an organoplatinum-amine system: tautomers having either a bridging hydrogen with platinum(II) or a hydride on platinum(IV). The X-ray crystal structure at 100 K of [Pt{C10H6(NMe2)-8-C,N}{C10H6(NHMe2)-8-C}(Br)]

Wehman-Ooyevaar, Ingrid C. M.; Grove, David M.; Sluis, P. van der; Spek, Anthony L.; Koten, Gerard van

doi:10.1039/c39900001367

Cited by 30 publications

(23 citation statements)

References 6 publications

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“…As reported, C−H activation can take place in similar systems having only one coordinated phosphine 14b, On the basis of these considerations we believe that the probable mechanism for the formation of 11 involves the precoordination of only the phosphine group to the platinum center. The formed intermediate undergoes reversible C−H bond activation, whereas the noncoordinated amine group drives the overall reaction toward 11 by deprotonation of the Pt(IV) center …”

Section: Resultssupporting

confidence: 74%

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

et al. 1997

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Reaction of the new aromatic aminophosphine ligand 1-((diethylamino)methyl)-3-((di-tert-butylphosphino)methyl)-2,4,6-trimethylbenzene (4) with [Rh(COE)2Cl]2 (COE = cyclooctene) or with [Rh(ethylene)2Cl]2 at room temperature results in selective carbon−carbon bond activation, yielding the complex ClRh(CH3)[C6H(CH3)2(CH2N(C2H5)2)(CH2P(t-Bu)2)] (5). No competing C−H activation was observed during the course of the reaction. When 4 was reacted with (COD)PtCl2 (COD = cyclooctadiene), selective C−H activation of the methyl group situated between the phosphine and amine groups took place, with concomitant intramolecular H transfer to the amine ligand, resulting in the zwitterionic Pt(II) complex Cl2PtCH2(C6H(CH3)2(CH2NH(C2H5)2)(CH2P(t-Bu)2) (11).

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Section: Resultssupporting

confidence: 74%

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

et al. 1997

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“…The effect of the trans ligand on the coupling constant should be noted. The chemical shift and coupling constant for Tp‘PtPh 2 H are similar to those of other complexes with trans nitrogen donor ligands. , …”

Section: Resultssupporting

confidence: 66%

Solid-State Structure of Tp‘PtMe₂H, a Dimethylhydrido Platinum(IV) Complex

1996

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The solid-state X-ray structure of Tp‘PtMe2H has been determined. This platinum(IV) hydride derivative is stable at room temperature and crystallizes in an orthorhombic cell (space group P cmn , Z = 4, a = 8.1292(8) Å, b = 13.3862(9) Å, and c = 17.9670(16) Å). The hydride ligand was not located. The complex was synthesized as one of a series of organometallic platinum(IV) derivatives with Tp‘ (Tp‘ = hydridotris(3,5-dimethylpyrazolyl)borate) in the coordination sphere. These octahedral platinum(IV) Tp‘PtMe2X and Tp‘PtPh2X complexes were prepared by formal oxidation of platinum(II) intermediates ([K][Tp‘PtMe2] and [K][Tp‘PtPh2]) with electrophiles (HX, MeI, I2). Thermogravimetric analysis (TGA) was employed to determine the solid-state decomposition temperatures for these platinum(IV) organometallic complexes.

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“…Another example involving a d 10 metal is provided by the adsorption of water on Pt(111), where recent evidence for hydrogen bonds between hydrogen atoms in water and Pt has been presented (30). Extensive experimental and computational evidence has also been provided for the involvement of a PtOHN hydrogen bond in zwitterionic Pt(II) complexes with a properly situated ammonium group (31)(32)(33). By x-ray crystallography an almost linear three-center PtOHN arrangement was observed (34).…”

Section: Resultsmentioning

confidence: 99%

OH–Pd(0) interaction as a stabilizing factor in palladium-catalyzed allylic alkylations

Hallman

Frölander²,

Wondimagegn³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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In palladium-catalyzed alkylations of allylic acetates with malonate as nucleophile, catalysts with oxazoline ligands bearing hydroxymethyl substituents in 4-position have been shown by density functional theory computations to undergo a conformational change on nucleophilic attack, which is accompanied by reduction of Pd(II) to Pd(0). The conformations of the Pd(0) complexes were shown to be governed by the presence of a hydrogen bond with the metal center acting as a hydrogen bond acceptor. The conformational change, which is absent in catalysts with O-alkylated analogs, largely affects the enantioselectivity of the catalytic process. This process is a previously uninvestigated example of where this type of weak hydrogen bond has been shown to influence the stereochemistry of a chemical reaction.A symmetric metal catalysis constitutes a powerful method for the preparation of enantiopure chiral compounds (1-3). To achieve high selectivity in the catalytic reactions, proper design of chiral ligands having the ability to transfer the chiral information to the reacting substrates is required. Proper design is usually accomplished by consideration of the steric and electronic demands of the catalytic process under study. Secondary interactions between the chiral ligand and the reacting species may influence the conformation of the catalyst, thereby affecting the stereoselectivity (4). At the same time, such interactions may be used to tune the electronic properties, resulting in increased reactivity of the catalytic system. Several examples of increased stereoselectivity and͞or acceleration of catalytic processes by ligands containing properly situated hydroxy groups have been reported. In rhodium-catalyzed hydrogenations of olefins, hydroxy substituents in the ligands have been shown to have remarkable effects. Thus, Knowles et al. (5) observed that a (R,R)-1,2-ethanediylbis[(2-methoxyphenyl)-phenylphosphine] derivative with the methoxy groups replaced by hydroxy groups provided high enantioselectivity, although it was at the expense of the high reactivity. Later, Börner (ref. 6 and references cited therein) noted similar effects for other types of ligands and provided evidence that properly situated hydroxy groups in the ligands coordinate to the cationic rhodium center by their oxygen lone pairs. Hayashi and coworkers (7-9) observed an accelerating effect by hydroxy groups in palladium-catalyzed allylic alkylations by using ferrocenylphosphine ligands. The effect was believed to be caused by an attractive interaction involving hydrogen bonding between a hydroxy group in the ligand and the nucleophile.We recently found that use of 2-(1-hydroxyalkyl)-(1a) and 2-(1-alkoxyalkyl)pyridinooxazolines (1b) as ligands in palladium-catalyzed allylic alkylations with malonate resulted in profoundly different enantioselectivities, ligands with (R*,R*)-configuration of the former type and those with (R*,S*)-configuration of the latter type, resulting in higher enantioselectivity than their diastereomers (10). This difference...

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A hydrogen atom in an organoplatinum-amine system: tautomers having either a bridging hydrogen with platinum(II) or a hydride on platinum(IV). The X-ray crystal structure at 100 K of [Pt{C10H6(NMe2)-8-C,N}{C10H6(NHMe2)-8-C}(Br)]

Cited by 30 publications

References 6 publications

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

Solid-State Structure of Tp‘PtMe₂H, a Dimethylhydrido Platinum(IV) Complex

OH–Pd(0) interaction as a stabilizing factor in palladium-catalyzed allylic alkylations

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A hydrogen atom in an organoplatinum-amine system: tautomers having either a bridging hydrogen with platinum(II) or a hydride on platinum(IV). The X-ray crystal structure at 100 K of [Pt{C10H6(NMe2)-8-C,N}{C10H6(NHMe2)-8-C}(Br)]

Cited by 30 publications

References 6 publications

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

A PCN Ligand System. Exclusive C−C Activation with Rhodium(I) and C−H Activation with Platinum(II)

Solid-State Structure of Tp‘PtMe2H, a Dimethylhydrido Platinum(IV) Complex

OH–Pd(0) interaction as a stabilizing factor in palladium-catalyzed allylic alkylations

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Solid-State Structure of Tp‘PtMe₂H, a Dimethylhydrido Platinum(IV) Complex