Oxidative Addition of S−S Bonds to Dimethylplatinum(II) Complexes: Evidence for a Binuclear Mechanism

Bonnington, Kevin J.; Jennings, Michael C.; Puddephatt, Richard J.

doi:10.1021/om800776b

Cited by 48 publications

(40 citation statements)

References 81 publications

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“…The formation of Pt(IV)-S species in the next stages can be explained by oxidation of the Pt(II)-S by di-and polysulfide groups as reported in refs [57,58]. The oxidative capability of the -S-S-species arising at the sulfide mineral surfaces upon their prolonged oxidation seems to be in fact mediated by Fe(III) entities and oxygen.…”

Section: Discussionmentioning

confidence: 74%

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

2018

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The interaction of aqueous solutions bearing platinum-group elements (PGEs) with sulfides is important for understanding the formation and weathering of PGE ore deposits, mineral processing, and synthesis of nanomaterials. Here, the surface species formed upon the contact of the main sulfide minerals (pyrite, pyrrhotite, galena, chalcopyrite and valleriite) with the solutions of H 2 PtCl 6 (pH 1.5, 20 • C) have been studied using X-ray photoelectron spectroscopy (XPS). Uptake of Pt increased gradually with increasing interaction time, and depended, as well as the composition of immobilized products, on the mineral nature and the state of its surface, e.g., the chemical pre-treatment. The highest rate of Pt deposition was observed on galena and valleriite and the lowest on pyrite and pyrrhotite. The preliminary moderate oxidation of pyrrhotite promoted Pt deposition, which, however, was hindered under harsh reaction conditions. The pre-oxidation of pyrite in all cases resulted in a decrease of the Pt deposition. Initially, Pt(IV) chloride complexes adsorb onto the mineral surface, and then the reduction of Pt(IV) to Pt(II) and substitution of chloride ions with sulfide groups occur forming sulfides of Pt(II) and then, Pt(IV). The reduction of Pt species to the metallic state was observed at valleriite after 24 h, probably due the negative charge of the sulfide nanolayers of this sulfide-hydroxide composite mineral.

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Section: Discussionmentioning

confidence: 74%

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

2018

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“…5,6 However, these reactions very often follow an S N 2 pathway, 7−11 with the metal center acting as nucleophile through the filled d z 2 orbital. In addition, Puddephatt and Canty have shown that OA to Pt(II) complexes of planar diimines follow a binuclear stepwise mechanism, with two π−stacked units involved in the initial oxidation step, 12,13 providing evidence of the role of metallophyllic interactions on the chemical reactivity of mononuclear d 8 complexes.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Half-Lantern Pt₂(II,II) Compounds by Halocarbons. Evidence of Dioxygen Insertion into a Pt(III)–CH₃ Bond

et al. 2015

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The half-lantern compound [{Pt(bzq)(μ-N^S)}2] (1) [bzq = benzo[h]quinoline, HN^S = 2-mercaptopyrimidine (C4H3N2HS)] reacts with CH3I and haloforms CHX3 (X = Cl, Br, I) to give the corresponding oxidized diplatinum(III) derivatives [{Pt(bzq)(μ-N^S)X}2] (X = Cl 2a, Br 2b, I 2c). These compounds exhibit half-lantern structures with short intermetallic distances (∼2.6 Å) due to Pt-Pt bond formation. The halogen abstraction mechanisms from the halocarbon molecules by the Pt2(II,II) compound 1 were investigated. NMR spectroscopic evidence using labeled reagents support that in the case of (13)CH3I the reaction initiates with an oxidative addition through an SN2 mechanism giving rise to the intermediate species [I(bzq)Pt(μ-N^S)2Pt(bzq)((13)CH3)}]. However, with haloforms the reactions proceed through a radical-like mechanism, thermally (CHBr3, CHI3) or photochemically (CHCl3) activated, giving rise to mixtures of species [X(bzq)Pt(μ-N^S)2Pt(bzq)R] (3a-c) and [X(bzq)Pt(μ-N^S)2Pt(bzq)X] (2a-c). In these cases the presence of O2 favors the formation of species 2 over 3. Transformation of 3 into 2 was possible upon irradiation with UV light. In the case of [I(bzq)Pt(μ-N^S)2Pt(bzq)((13)CH3)}] (3d), in the presence of O2 the formation of the unusual methylperoxo derivative [I(bzq)Pt(μ-N^S)2Pt(bzq)(O-O(13)CH3)}] (4d) was detected, which in the presence of (13)CH3I rendered the final product [{Pt(bzq)(μ-N^S)I}2] (2c) and (13)CH3OH.

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“…The geometry of the complexes motivates oxidation experiments, which should lead to a direct Pd À Pd bond. [44] However, first test experiments with disulfides as oxidation reagents were unsuccessful (see the Experimental Section). Even at elevated temperatures, no reaction was monitored, thus indicating a high complex stability.…”

Section: Figure 5 Molecular Structures Of the Dinuclear Complexes A)mentioning

confidence: 99%

Bisguanidines with Biphenyl, Binaphthyl, and Bipyridyl Cores: Proton‐Sponge Properties and Coordination Chemistry

Maronna

Hübner

Enders

et al. 2013

Chemistry A European J

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Herein, we report on the synthesis, protonation, and coordination chemistry of chelating guanidine ligands with biphenyl, binaphthyl, and bipyridyl backbones. The ligands are shown to be proton sponges, and this protonation was studied experimentally and by using quantum-chemical calculations. Group 10 metal (Ni, Pd, and Pt) complexes with different metal/ligand ratios were synthesized. In the case of the bipyridyl systems, coordination occurs exclusively at the pyridine N atoms, as opposed to protonation. The spin-density distribution and the magnetism were evaluated for a series of paramagnetic Ni(II) complexes with the aid of paramagnetic NMR spectroscopic studies in alliance with quantum-chemical calculations and magnetic (SQUID) measurements. Through direct delocalization from the singly occupied molecular orbitals (SOMOs), a significant amount of spin density is placed on the guanidinyl groups, and spin polarization also transports spin density onto the aromatic backbone.

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Oxidative Addition of S−S Bonds to Dimethylplatinum(II) Complexes: Evidence for a Binuclear Mechanism

Cited by 48 publications

References 81 publications

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

Oxidation of Half-Lantern Pt₂(II,II) Compounds by Halocarbons. Evidence of Dioxygen Insertion into a Pt(III)–CH₃ Bond

Bisguanidines with Biphenyl, Binaphthyl, and Bipyridyl Cores: Proton‐Sponge Properties and Coordination Chemistry

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Oxidative Addition of S−S Bonds to Dimethylplatinum(II) Complexes: Evidence for a Binuclear Mechanism

Cited by 48 publications

References 81 publications

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

X-ray Photoelectron Spectroscopy (XPS) Study of the Products Formed on Sulfide Minerals Upon the Interaction with Aqueous Platinum (IV) Chloride Complexes

Oxidation of Half-Lantern Pt2(II,II) Compounds by Halocarbons. Evidence of Dioxygen Insertion into a Pt(III)–CH3 Bond

Bisguanidines with Biphenyl, Binaphthyl, and Bipyridyl Cores: Proton‐Sponge Properties and Coordination Chemistry

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Oxidation of Half-Lantern Pt₂(II,II) Compounds by Halocarbons. Evidence of Dioxygen Insertion into a Pt(III)–CH₃ Bond