Evaluating stereoelectronic properties of bulky dialkylterphenyl phosphine ligands

Marín, Mario; Moreno, Juan J.; Alcaide, María; Álvarez, Eleuterio; López‐Serrano, Joaquín; Campos, Jesús; Nicasio, M. Carmen; Carmona, Ernesto

doi:10.1016/j.jorganchem.2019.06.003

Cited by 27 publications

(30 citation statements)

References 79 publications

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“…Compounds 1a and 1c were readily prepared by the same procedure previously reported for 1b. 26 The steric shielding provided by these phosphines follows the order PCyp2Ar Xyl2 > PMe2Ar Dipp2 > PMe2Ar Xyl2 , 25 which has a direct impact on the reactivity of their gold triflimide complexes with compound 2, as will be discussed in detail in the following sections. For instance, when compound 1a, based on the less congested phosphine, is combined with an equimolar mixture of 2, the corresponding bimetallic Lewis adduct 4a is readily formed (Scheme 2).…”

Section: Frustration Versus Lewis Adduct Formationmentioning

confidence: 98%

“…To switch between the two extreme scenarios we have targeted herein three Lewis acidic gold complexes stabilized by terphenyl phosphines, PR2Ar' (R = alkyl; Ar' = C6H3-2,6-Ar2), whose steric parameters were recently investigated by our group (Figure 1). 25 We provide a combined experimental and computational investigation that includes isolation and reactivity studies of competent intermediates, kinetic investigations and density functional theory (DFT) calculations with the aim of elucidating the mechanism of dihydrogen activation by Au(I)/Pt(0) TMOFLPs (Scheme 1), paying special attention to the effects of M-M interaction/frustration balance.…”

Section: Introductionmentioning

confidence: 99%

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Evidence for Genuine Bimetallic Frustrated Lewis Pair Activation of Dihydrogen with Gold(I)/Platinum(0) Systems

Hidalgo

Moreno

Pérez‐Jiménez

et al. 2020

Chemistry A European J

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A joint experimental/computational effort to elucidate the mechanism of dihydrogen activation by a gold(I)/platinum(0) metal-only frustrated Lewis pairs is described herein. We have also investigated the drastic effects on H2 activation derived from subtle ligand modifications. The importance of the balance between bimetallic adduct formation and complete frustration has been interrogated, providing for the first time evidence for genuine metal-only FLP reactivity in solution. The origin of a strong inverse kinetic isotopic effect has also been clarified, offering further support for the proposed bimetallic FLP-type cleavage of dihydrogen.

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Section: Frustration Versus Lewis Adduct Formationmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Evidence for Genuine Bimetallic Frustrated Lewis Pair Activation of Dihydrogen with Gold(I)/Platinum(0) Systems

Hidalgo

Moreno

Pérez‐Jiménez

et al. 2020

Chemistry A European J

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“…14 We now tested the analogous reactivity using gold precursors [(PMe2Ar Xyl2 )Au(NTf2)] 1a and [(PCyp2Ar Xyl2 )Au(NTf2)] 1c in our search for regioselectivity effects while keeping unaltered the basicity of the metallic base (2). Moreover, the acidity of the gold precursors 1a-c barely differs from one another, 15 thus any anticipated outcomes mostly build on steric grounds. In fact, we found a drastic change in product distribution from the less hindered system (1a, PMe2Ar Xyl2 ) to the more congested one (1c, PCyp2Ar Xyl2 ), as determined by NMR spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Tuning Activity and Selectivity During Alkyne Activation by Gold(I)/Platinum(0) Frustrated Lewis Pairs

Hidalgo¹,

Pérez‐Jiménez²,

Maya³

et al. 2020

Preprint

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Introducing transition metals into frustrated Lewis pair systems has attracted considerable attention in recent years. Here we report a selection of three metal-only frustrated systems based on Au(I)/Pt(0) combinations and their reactivity towards alkynes. We have inspected the activation of the simplest alkyne, namely acetylene, as well as of other internal and terminal triply bonded hydrocarbons. The gold(I) fragments are stabilized by three bulky phosphines bearing terphenyl groups. We have observed that subtle modifications on the substituents of these ligands proved critical to control the regioselectivity of acetylene activation and the product distribution resulting from C(sp)—H cleavage of phenylacetylene. A mechanistic picture based on experimental observations and computational analysis is provided. As a result of the cooperative action of the two metals of the frustrated pairs, several uncommon heterobimetallic structures have been fully characterized.

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“…With the aim of investigating the properties of this type of ligands, we prepared a series of dialkylterphenyl phosphines with a variety of substituents both on the phosphorus atom and on the terphenyl moiety and evaluated their electronic and steric parameters . These studies highlighted their strong basicity and their superior steric protection when compared to dicyclohexylbiaryl phosphines . Moreover, the coordination properties of terphenyl phosphines towards a variety of late transition metals including Rh, Ir, Ni, Pt, and Au proved their ability to adopt different coordination modes involving the P atom and one of the flanking aryl rings of the terphenyl fragment .…”

Section: Introductionmentioning

confidence: 99%

Dialkylterphenyl Phosphine‐Based Palladium Precatalysts for Efficient Aryl Amination of N‐Nucleophiles

Rama

Maya

Nicasio

2020

Chemistry A European J

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Aseries of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR 2 Ar' (R = Me, Et, iPr, Cyp (cyclopentyl), Ar' = Ar Dipp2 ,A r Xyl2f ,D ipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl = xylyl) have been prepareda nd structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e.,M ea nd Et substituents) whereas the largest phosphines provided cationic palladacycles in whicht he phosphines adopted ab identate hemilabile k 1 -P,h 1 -C arene coordination mode.T he influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl aminationr eactions.C ationicc omplexes bearing the phosphines Pi-Pr 2 Ar Xyl2 andP Cyp 2 Ar Xyl2 weret he most active of the series. Thesep recatalysts have demonstrated ah igh versatility and efficiency in the coupling of av ariety of nitrogen nucleophiles, including secondary amines, alkyl amines,a nilines, and indoles, with electronically deactivated and ortho-substituted aryl chloridesa tl ow catalyst loadings (0.25-0.75 mol % Pd) and withoutexcess ligand.[a] R.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.Scheme2.Synthesis of complexes 2a and 2b.Scheme3.Generalsynthesis of complexes 3d and 3e.

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Evaluating stereoelectronic properties of bulky dialkylterphenyl phosphine ligands

Cited by 27 publications

References 79 publications

Evidence for Genuine Bimetallic Frustrated Lewis Pair Activation of Dihydrogen with Gold(I)/Platinum(0) Systems

Evidence for Genuine Bimetallic Frustrated Lewis Pair Activation of Dihydrogen with Gold(I)/Platinum(0) Systems

Tuning Activity and Selectivity During Alkyne Activation by Gold(I)/Platinum(0) Frustrated Lewis Pairs

Dialkylterphenyl Phosphine‐Based Palladium Precatalysts for Efficient Aryl Amination of N‐Nucleophiles

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