Computational Characterization of Bidentate P-Donor Ligands: Direct Comparison to Tolman’s Electronic Parameters

Kégl, Tímea R.; Pálinkás, Noémi; Kollár, László; Kégl, Tamás

doi:10.3390/molecules23123176

Cited by 21 publications

(12 citation statements)

References 44 publications

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“…[5][6][7][8][9] The broad range of applications of organometallic compounds in catalytic processes originates from their favorable redox properties, which can be easily tuned and optimized to the specific chemical process of interest by alteration of the metal center but even more importantly, by structural modification of the ligand sphere. With respect to the oxidative addition reaction, the addition of strongly coordinating σ-donor ligands such as phosphines, [10] N-heterocyclic carbenes [11] or bidentate nitrogen-containing molecules, [12] can be beneficial to enhance the chemical stability and, thus, the long-term performance of the molecular catalyst, as well as to provide a handle for tuning the oxidation potential of the metal center, and in consequence, the catalytic turnover. [13] Sawamura et al [14] discovered that the yields of Rh-catalyzed borylation with assisting phosphine ligand increased by approximately 10 % compared to phosphine-free conditions.…”

Section: Introductionmentioning

confidence: 99%

Bidentate Rh(I)‐Phosphine Complexes for the C−H Activation of Alkanes: Computational Modelling and Mechanistic Insight

et al. 2022

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The CÀ H activation and subsequent carbonylation mediated by metal complexes, i. e., Rh(I) complexes, has drawn considerable attention in the past. To extend the mechanistic insight from Rh complexes featuring monodentate ligands like P(Me) 3 towards more active bisphosphines (PLP), a computationally derived fully conclusive mechanistic picture of the Rh(I)-catalyzed CÀ H activation and carbonylation is presented here. Depending on the nature of the bisphosphine ligand, the highest lying transition state (TS) is associated either to the initial CÀ H activation in [Rh(PLP)(CO)(Cl)] or to the rearrangement of the chloride in [Rh(PLP)(H)(R)(Cl)]. The chloride rearrangement was found to play a key role in the subsequent carbonylation. A set of 20 complexes of different architectures was studied, in order to fine tune the CÀ H activation in a knowledge-driven approach. The computational analysis suggests that a flexible ligand architecture with aromatic rings can potentially increase the performance of Rh-based catalysts for the CÀ H activation.

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Section: Introductionmentioning

confidence: 99%

Bidentate Rh(I)‐Phosphine Complexes for the C−H Activation of Alkanes: Computational Modelling and Mechanistic Insight

et al. 2022

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“…Moreover, the computed electronic parameter (CEP), that is the total symmetric (A) carbonyl stretching frequency in the Ni(CO) 3 L complex type, was calculated for ligand L1 ( Figure 4 ). The obtained value was ν A = 2083.2 cm −1 , which is in between the CEPs of triphenyl phosphite (ν A = 2085.3 cm −1 ) and trimethyl phosphite (ν A = 2079.5 cm −1 ), calculated at the same level of theory [ 45 ]. Since this parameter is a generally accepted measure for the Lewis basicity of P-donor ligands, we concluded that the new tris-BINOL-neomenthol monophosphites are expected to present a stronger Lewis base character compared with that of triphenyl phosphite.…”

Section: Resultsmentioning

confidence: 75%

Stereoisomeric Tris-BINOL-Menthol Bulky Monophosphites: Synthesis, Characterisation and Application in Rhodium-Catalysed Hydroformylation

et al. 2022

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Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a chiral (+)- or (−)-neomenthyloxy group were synthesised and fully characterised by NMR spectroscopy and X-ray crystallography. The respective tris-monophosphites were thereof prepared and fully characterised. The coordination ability of the new bulky phosphites with Rh(CO)2(acac), was attested by 31P NMR, which presented a doublet in the range of δ = 120 ppm, with a 1J(103Rh-31P) coupling constant of 290 Hz. The new tris-binaphthyl phosphite ligands were further characterised by DFT computational methods, which allowed us to calculate an electronic (CEP) parameter of 2083.2 cm−1 and an extremely large cone angle of 345°, decreasing to 265° upon coordination with a metal atom. Furthermore, the monophosphites were applied as ligands in rhodium-catalysed hydroformylation of styrene, leading to complete conversions in 4 h, 100% chemoselectivity for aldehydes and up to 98% iso-regioselectivity. The Rh(I)/phosphite catalytic system was also highly active and selective in the hydroformylation of disubstituted olefins, including (E)-prop-1-en-1-ylbenzene and prop-1-en-2-ylbenzene.

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“…The S4' parameter (ΣR 1 -P-R 2 − ΣNi-P-R) provides an insight into the strain exerted by the bulk on the Ni−P bond. Plotted against Tolman's electronic parameter, 47 we get a visualization of phosphine ligand space.…”

Section: ■ Theoretical Studies On Electronic and Steric Properties Of...mentioning

confidence: 99%

Room-Temperature Amination of Chloroheteroarenes in Water by a Recyclable Copper(II)-Phosphaadamantanium Sulfonate System

Parmar¹,

Somvanshi

Kori

et al. 2021

J. Org. Chem.

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Buchwald–Hartwig amination of chloroheteroarenes has been a challenging synthetic process, with very few protocols promoting this important transformation at ambient temperature. The current report discusses about an efficient copper-based catalytic system (Cu/PTABS) for the amination of chloroheteroarenes at ambient temperature in water as the sole reaction solvent, a combination that is first to be reported. A wide variety of chloroheteroarenes could be coupled efficiently with primary and secondary amines as well as selected amino acid esters under mild reaction conditions. Catalytic efficiency of the developed protocol also promotes late-stage functionalization of active pharmaceutical ingredients (APIs) such as antibiotics (floxacins) and anticancer drugs. The catalytic system also performs efficiently at a very low concentration of 0.0001 mol % (TON = 980,000) and can be recycled 12 times without any appreciable loss in activity. Theoretical calculations reveal that the π-acceptor ability of the ligand PTABS is the main reason for the appreciably high reactivity of the catalytic system. Preliminary characterization of the catalytic species in the reaction was carried out using UV–VIS and ESR spectroscopy, providing evidence for the Cu(II) oxidation state.

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Computational Characterization of Bidentate P-Donor Ligands: Direct Comparison to Tolman’s Electronic Parameters

Cited by 21 publications

References 44 publications

Bidentate Rh(I)‐Phosphine Complexes for the C−H Activation of Alkanes: Computational Modelling and Mechanistic Insight

Bidentate Rh(I)‐Phosphine Complexes for the C−H Activation of Alkanes: Computational Modelling and Mechanistic Insight

Stereoisomeric Tris-BINOL-Menthol Bulky Monophosphites: Synthesis, Characterisation and Application in Rhodium-Catalysed Hydroformylation

Room-Temperature Amination of Chloroheteroarenes in Water by a Recyclable Copper(II)-Phosphaadamantanium Sulfonate System

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