Chlorohydridobis(Trialkylphosphine)‐Platinum(II) Complexes

Phillips, Julia R.; Trogler, William C.; Brammer, Mick; Packett, Dianne L.

doi:10.1002/9780470132609.ch46

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…This irreversible transformation was very slow at −50 °C, occurred at an increased rate above −30 °C, and went rapidly to completion at 0 °C. The 31 P, 195 Pt, and 1 H NMR data of 15 Mes are similar to those of 11 Mes , and the 31 P and 195 Pt chemical shifts match those of known complexes trans -[Pt(R 3 P) 2 (H)(Cl)], which can also be readily prepared by hydride reduction of Pt(II) precursors . The structural assignment is also backed by the good match of the observed 195 Pt NMR chemical shift with the calculated value of −5114 ppm for the N-Me substituted model compound 11 Me .…”

Section: Results and Discussionsupporting

confidence: 64%

Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

et al. 2017

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The outcome of the reduction of [(cod)PtX] (X = Cl, Br; cod = 1,5-cyclooctadiene) with N-heterocyclic phosphenium hydrides NHP-H depends strongly on the steric demand of the N-aryl group R and the nature of X. Reaction of [(cod)PtCl] with NHP-H featuring bulky N-Dipp groups produced an unprecedented monomeric phosphenium metal(0) halide [(NHP)(NHP-H)PtCl] stabilized by a single phosphine ligand. The phosphenium unit exhibits a pyramidal coordination geometry at the phosphorus atom and may according to DFT calculations be classified as a Z-type ligand. In contrast, reaction of [(cod)PtBr] with the sterically less protected NHP-H afforded a mixture of donor-ligand free oligonuclear complexes [{(NHP)PtBr}] (n = 2, 3), which are structural analogues of known palladium complexes with μ-bridging phosphenium units. All reductions studied proceed via spectroscopically detectable intermediates, several of which could be unambiguously identified by means of multinuclear (H, P,Pt) NMR spectroscopy and computational studies. The experimental findings reveal that the phosphenium hydrides in these multistep processes adopt a dual function as ligands and hydride transfer reagents. The preference for the observed intricate pathways over seemingly simpler ligand exchange processes is presumably due to kinetic reasons. The attempt to exchange the bulky phosphine ligand in [(NHP)(NHP-H)PtCl] by MeP resulted in an unexpected isomerization to a platinum(0) chlorophosphine complex via a formal chloride migration from platinum to phosphorus, which accentuates the electrophilic nature of the phosphenium ligand. Phosphenium metal(0) halides of platinum further show a surprising thermal stability, whereas the palladium complexes easily disintegrate upon gentle heating in dimethyl sulfoxide to yield metal nanoparticles, which were characterized by TEM and XRD studies.

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Section: Results and Discussionsupporting

confidence: 64%

Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

et al. 2017

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“…The sodium naphthalide preparation of trans-[(Me 3 P) 2 PtHCl] is inconvenient, and Trogler later published a preparation of trans-[(Me 3 P) 2 PtHCl] based on the sodium borohydride reduction of cis-[(Me 3 P) 2 PtCl 2 ] in methanol in the presence of diethylamine. 14 In an attempt to understand the nature of the postulated catalytic impurity in Trogler's system, we became interested in a reaction first reported by Minghetti and co-workers 15 who found that styrene reacted with the dinuclear H-bridged cationic complex 1 to give the bridging alkylidene complex 2, as shown in eqn (2). This involved the transfer of a hydride in 1 to the benzylic carbon of styrene.…”

Section: Introductionmentioning

confidence: 99%

Studies towards the catalytic anti-Markovnikov functionalisation of alkenes

Richard

Parkins

2008

New J. Chem.

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In 1986 Jensen and Trogler reported that a biphasic system containing the mononuclear complex trans-[(Me 3 P) 2 PtHCl] and NaOH catalysed the anti-Markovnikov hydration of 1-hexene to 1-hexanol. The unusual method of preparation could also give rise to dinuclear complexes with bridging hydride ligands. We have tested some dinuclear complexes for catalytic activity and discovered that on heating these yield trinuclear complexes. Using the independently prepared trinuclear complex [(dppe) 3 Pt 3 H 3 ] + , we found that it acted as a catalyst for the reaction between 1-octene and methanol to give 1-methoxyoctane, although the results were somewhat erratic. A cause of the erratic behaviour was found to be the presence of varying amounts of hydroperoxide impurities, which underwent a Hock rearrangement in acidic conditions.

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Novel, Efficient, Palladium-Based System for the Polymerization of Norbornene Derivatives: Scope and Mechanism

et al. 2001

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1,5-Cyclooctadiene)(CH 3 )Pd(Cl)], when reacted in situ with 1 equiv of a monodentate phosphine ligand and 1 equiv of the complex Na + [3,5-(CF 3 ) 2 C 6 H 3 ] 4 B -was found to catalyze the vinyl addition polymerization of norbornene derivatives, including those with pendant oxygen functionalities. For norbornene, a polymerization rate of 1000 tons norbornene/mol Pd‚h was observed at 25°C. For several norbornene derivatives, the molecular weight of the polymer was found to decrease with increasing amounts of added 2-propanol. Mechanistic data confirm a vinyl insertion mechanism for these polymerizations. The polymerization rate was found to decrease dramatically for norbornene derivatives with pendant oxygen functionalities. The effect of coordinating solvents and the uptake of endo vs exo isomers for functionalized norbornenes was tested. Experiments show that (a) the endo isomer reacts more slowly than the exo isomer and (b) both isomers react much more slowly compared to norbornene derivatives lacking coordinating functionalities. Reaction of 5-norbornene carboxylic acid ethyl ester with the [(Et 3 P) 2 Pt(H)] + fragment yields the endo-inserted product exhibiting intramolecular coordination of the ester functionality to the platinum center. The formation of chelates, both upon the coordination of the endo-fuctionalized nobornene and in the endo-inserted product, appears to be responsible, in part, for the observed decrease in polymerization rate for functional norbornene derivates. A further reason for the diminution of activity of both the endo-and the exo-functionalized isomers is simply the coordination of the functionality. Of the two factors, the latter is the dominant one.

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Chlorohydridobis(Trialkylphosphine)‐Platinum(II) Complexes

Cited by 4 publications

References 11 publications

Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

Studies towards the catalytic anti-Markovnikov functionalisation of alkenes

Novel, Efficient, Palladium-Based System for the Polymerization of Norbornene Derivatives: Scope and Mechanism

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Chlorohydridobis(Trialkylphosphine)‐Platinum(II) Complexes

Cited by 4 publications

References 11 publications

Phosphenium Hydride Reduction of [(cod)MX2] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

Phosphenium Hydride Reduction of [(cod)MX2] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

Studies towards the catalytic anti-Markovnikov functionalisation of alkenes

Novel, Efficient, Palladium-Based System for the Polymerization of Norbornene Derivatives: Scope and Mechanism

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Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles

Phosphenium Hydride Reduction of [(cod)MX₂] (M = Pd, Pt; X = Cl, Br): Snapshots on the Way to Phosphenium Metal(0) Halides and Synthesis of Metal Nanoparticles