Preparation, characterization, and some reactions of hydridobis(tri-<i>tert</i>- butyl)phosphineplatinum(II) cation containing three-coordinate platinum

Goel, Ram G.; Srivastava, R. C.

doi:10.1139/v83-238

Cited by 43 publications

(44 citation statements)

References 6 publications

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“…Interestingly, the closely related species T1 (Fig. 5) does not include any solvent molecule filling the vacancy [19]. Moreover, the structures of S1a and S1c were fully confirmed by X-ray studies.…”

Section: Reviewmentioning

confidence: 90%

“…5). In the 80s, Goel et al proposed, from nuclear magnetic resonance (NMR) data, a T-shaped structure for the cationic hydride trans -[( t -Bu 3 P) 2 Pt(H)] + T1 containing bulky phosphine ligands [19]. However, it was not until 2005 when Braunschweig et al successfully characterized a true 14-electron T-shaped Pt(II) boryl complex T2a by means of X-ray studies [20].…”

Section: Reviewmentioning

confidence: 99%

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True and masked three-coordinate T-shaped platinum(II) intermediates

Ortuño¹,

Conejero²,

Lledós³

2013

Beilstein J. Org. Chem.

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SummaryAlthough four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation. Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C–H bond-activation processes.

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Section: Reviewmentioning

confidence: 90%

Section: Reviewmentioning

confidence: 99%

True and masked three-coordinate T-shaped platinum(II) intermediates

Ortuño¹,

Conejero²,

Lledós³

2013

Beilstein J. Org. Chem.

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“…In marked contrast, a smooth, quick reaction took place (<5 min) when a C 6 D 6 solution of TMOFLP 1/2 was subjected to H 2 atmosphere (0.5 bar). Full consumption of gold complex 1 took place, leading to a 1:1:1 mixture of unreacted 2, a new hydride-bridged digold complex 3, and the known platinum hydride 4 14 (Scheme 2). After around 12 hours the foregoing mixture converted into the hydride-bridged platinum-gold complex 5, that was obtained as the only metal-containing product (ca.…”

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confidence: 99%

Dihydrogen and Acetylene Activation by a Gold(I)/Platinum(0) Transition Metal Only Frustrated Lewis Pair

Campos

2017

J. Am. Chem. Soc.

123

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ABSTRACT:The first example of a Frustrated Lewis Pair (FLP) solely constructed around transition metal centers is described in this work. We have focused on the established capacity of Au(I) and Pt(0) complexes to act as Lewis acidic and basic fragments, respectively, while employing sufficiently bulky P t Bu 3 and terphenyl phosphine ligands. This avoids formation of metallic Lewis adducts and confers the Au(I)/Pt(0) pair a remarkable capacity to activate dihydrogen and acetylene molecules in a fashion that closely resembles that of traditional main group FLP systems. As a consequence, unusual heterobimetallic Au(I)/Pt(II) complexes containing hydride (-H), acetylide (-C≡CH) and vinylene (-HC=CH-) bridges have been isolated.The recent development of Frustrated Lewis Pairs (FLPs) has catapulted the chemistry of main group elements beyond its well-established limits, achieving reactivity patterns that were once restricted to transition metals (TMs).1 A prominent example with profound implications in metal-free catalytic hydrogenations, 2 is the activation of dihydrogen by phosphine/borane pairs. Despite their importance, the catalytic usefulness of FLPs is nevertheless limited to mainly hydrogenation and a few other reactions, 3 possibly as a consequence of the reluctance of main group elements to participate in electron-transfer and other fundamental organometallic reactions, which are key elementary steps in transition metal catalysis.Incorporation of TMs into FLPs is therefore a promising objective 4 and, as such, it has attracted recently considerable attention, as exemplified by the pioneering work of the groups of Wass 5 and Erker 6 on Zr/phosphine pairs and related systems. Although some TMs, in particular Pt(0) complexes, 7 have been employed as Lewis base (LB) partners in FLP-like designs, no examples of transition metal-only FLPs (TMOFLPs), where both the acidic and the basic functions are constructed on TMs, seen to be known, 8 despite the existence of a large number of heterobimetallic systems capable of activating small molecules in a fashion reminiscent of FLPs. 9,10Cationic Au(I) and neutral Pt(0) complexes have a well-known capacity to behave as LA and LB fragments, respectively. Hence, they were envisioned as suitable building blocks to frame an intermolecular TMOFLP. To attain frustration, triflimide Au(I) complex [Au(NTf 2 )(PMe 2 Ar Dipp2 )] (1), 11 containing the bulky terphenyl phosphine PMe 2 Ar Dipp2 (Ar Dipp2 = C 6 H 3 -2,6-(C 6 H 3 -2,6-i Pr 2 ) 2 ), 12 and the Pt(0) species [Pt(P t Bu 3 ) 2 ] (2), were utilized as FLP constituents. The present contribution reports the results of our preliminary investigation into the activation of H 2 and C 2 H 2 by the resulting cationic Au(I)/Pt(0) TMOFLP.Although the main 1 H and 31 P{ 1 H} NMR features of complexes 1 and 2 remained unaltered when their C 6 D 6 solutions were combined, upon mixing, the initially colorless solutions of 1 and 2 distinctly became bright yellow. Furthermore, in CD 2 Cl 2 as the solvent, the 31 P{ 1 H} NMR resonances of ...

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“…31 PNMR spectroscopy (Fc observed;S cheme 1). [12] This outcome suggests only transient stability of 2b in solution, with subsequent C À Hb ond homolysis accounting for the divergence from fully reversible one-electron oxidation of 1b observed by CV. [13] Reaction of 1bwith two equiv of [Fc] [PF 6 ] in the presence of excess hindered base 2,6-bis(decyl)pyridine (5 equiv), which is able to deprotonate 4,resulted in selective formation of 3b within 15 min.…”

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confidence: 99%

One‐Electron Oxidation of [M(P^tBu₃)₂] (M=Pd, Pt): Isolation of Monomeric [Pd(P^tBu₃)₂]⁺ and Redox‐Promoted C−H Bond Cyclometalation

et al. 2016

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Oxidation of zero-valent phosphine complexes [M(P t Bu 3 ) 2 ]( M = Pd, Pt) has been investigated in 1,2-difluorobenzene solution using cyclic voltammetry and subsequently using the ferrocenium cation as ac hemical redox agent. In the case of palladium, am ononuclear paramagnetic Pd I derivative was readily isolated from solution and fully characterized (EPR, X-ray crystallography Over the past few decades ar ich variety of chemistry has emerged based on the reactions of palladium and platinum complexes in the 0a nd + II formal oxidation states,e pitomized by the omnipresence of palladium catalyzed crosscoupling reactions in contemporary organic chemistry. [1,2] In contrast, the organometallic chemistry of well-defined complexes of these elements bearing formal + Ioxidation states is much less established and examples are largely limited to unstable or dinuclear species with distinct metal-metal bonds. [3,4] Halogen bridged palladium complexes of the type [Pd(m-X)(P t Bu 3 )] 2 (X = Br,I )a re notable examples and are believed to act as reservoirs for reactive {Pd 0 (P t Bu 3 )} fragments in catalytic transformations.[5] In other systems,Pd I and Pt I species have been postulated as intermediates,b ut with little supporting evidence.[6] With av iew to isolating welldefined mononuclear complexes in the + Io xidation state relevant to catalysis,wereport herein our work involving oneelectron oxidation of widely used and commercially available palladium(0) and platinum (0) ).

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Preparation, characterization, and some reactions of hydridobis(tri-tert- butyl)phosphineplatinum(II) cation containing three-coordinate platinum

Cited by 43 publications

References 6 publications

True and masked three-coordinate T-shaped platinum(II) intermediates

True and masked three-coordinate T-shaped platinum(II) intermediates

Dihydrogen and Acetylene Activation by a Gold(I)/Platinum(0) Transition Metal Only Frustrated Lewis Pair

One‐Electron Oxidation of [M(P^tBu₃)₂] (M=Pd, Pt): Isolation of Monomeric [Pd(P^tBu₃)₂]⁺ and Redox‐Promoted C−H Bond Cyclometalation

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Preparation, characterization, and some reactions of hydridobis(tri-tert- butyl)phosphineplatinum(II) cation containing three-coordinate platinum

Cited by 43 publications

References 6 publications

True and masked three-coordinate T-shaped platinum(II) intermediates

True and masked three-coordinate T-shaped platinum(II) intermediates

Dihydrogen and Acetylene Activation by a Gold(I)/Platinum(0) Transition Metal Only Frustrated Lewis Pair

One‐Electron Oxidation of [M(PtBu3)2] (M=Pd, Pt): Isolation of Monomeric [Pd(PtBu3)2]+ and Redox‐Promoted C−H Bond Cyclometalation

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One‐Electron Oxidation of [M(P^tBu₃)₂] (M=Pd, Pt): Isolation of Monomeric [Pd(P^tBu₃)₂]⁺ and Redox‐Promoted C−H Bond Cyclometalation