Transition metal (Rh and Fe) complexes and main-group (Se and B) adducts with N,N′-diphosphanyl NHC ligands: a study of stereoelectronic properties

Ai, Pengfei; Danopoulos, Andreas A.; Braunstein, Pierre

doi:10.1039/c6dt00318d

Cited by 17 publications

(6 citation statements)

References 55 publications

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“…39 The TEP, however, quantifies the overall electronic properties of ligands and does not separate the σ-donation and π-back-donation components. 40 In this context, Ganter's 77 Se and Bertrand's 31 P NMR methods are the most significant for the determination of the π-accepting property of singlet carbenes. 32,34 These methods rely on the 77 Se and 31 P NMR chemical shifts of the corresponding phosphinidene (NHC)-PPh and selenium (NHC)Se adducts, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Quantifying the Electronic and Steric Properties of 1,3-Imidazole-Based Mesoionic Carbenes (iMICs)

et al. 2020

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Imidazole-based mesoionic carbenes (iMICs) are a very promising class of carbon-donor ligands in synthesis and catalysis. However, a systematic study of the quantification of stereoelectronic properties of iMICs is lacking. This is most likely due to the absence of rational synthetic routes to suitable iMIC compounds. Herein, we report the synthesis of the appropriate phosphinidene (iMIC Ar )PPh (iMIC Ar = :CCH(NDipp) 2 CAr; Ar = Ph (5a), DMP (5b); DMP = 4-Me 2 NC 6 H 4 ; Dipp = 2,6-iPr 2 C 6 H 3 ), selenium (iMIC Ar )Se (Ar = Ph (6a), DMP (6b)), and nickel carbonyl compounds (iMIC Ar )Ni(CO) 3 (Ar = Ph (7a), DMP (7b)). The π-accepting property of iMIC Ar (Ar = Ph (2a), DMP (2b)) has been evaluated by 31 P and 77 Se NMR spectroscopic analyses of 5 and 6, respectively. The overall donor property of 2 has been assessed by determining the Tolman electronic parameter (TEP) of 7. Studies suggest that iMIC Ar (2) are stronger σ donors and weaker π acceptors compared to classical N-heterocyclic carbenes (NHCs). The steric profile of iMIC Ar (2) has been obtained by calculating the percentage buried volume (%V bur ) for (iMIC Ar

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Section: ■ Results and Discussionmentioning

confidence: 99%

Quantifying the Electronic and Steric Properties of 1,3-Imidazole-Based Mesoionic Carbenes (iMICs)

et al. 2020

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“…Imidazoline-2-chalcogenone ligands NHCE (NHC = N-heterocyclic carbene, E = S, Se) and their transition-metal complexes play a crucial role in organometallic and coordination chemistry as well as in catalysis. − Imidazoline-2-chalcogenone ligands are good σ-donors and weak π-acceptors and can be easily modified using appropriate available NHC precursors to allow fine tuning of steric and electronic properties of the center metal complexes. A series of transition-metal complexes with imidazoline-2-chalcogenone ligands have been synthesized for various applications such as C–C bond formation, ,, borylation of alkynes, biomimetic activity, and hydrogen transfer reaction , in recent years.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Catalytic Activities of Palladium Complexes with Phenylene-Bridged Bis(thione) Ligands

et al. 2019

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The neutral phenylene-bridged bis(thione) compounds, 1,3-bis(3′-ethylimidazolyl-2′-thione)benzene (Betb), 1,3-bis(3′-butylimidazolyl-2′-thione)benzene (Bbtb), and 1,3-bis(3′-allylimidazolyl-2′-thione)benzene (Batb), have been synthesized and characterized. Reactions of palladium precursor PdCl 2 (CH 3 CN) 2 with phenylene-bridged bis-(thione) ligands in 1:2 ratio resulted in the formation of the complexes: PdCl 2 (L) 2 (L = Betb, 3a; L = Bbtb, 3b; L = Batb, 3c, respectively). In contrast, treatment of the ligands with PdCl 2 (CH 3 CN) 2 in 1:1 ratio gave cyclometalation palladium complexes Pd 2+ Cl(L − ) (L = Betb-H, 4a; L = Bbtb-H, 4b; L = Batb-H, 4c) through the metal-induced C−H activation. Complexes 4a−c can also be obtained by the reaction of bis(thione) ligands and PdCl 2 in 1:1 ratio. The reaction of 3a−c with additional PdCl 2 (CH 3 CN) 2 also afforded complexes 4a−c. All ligands and palladium complexes were fully characterized by one-/two-dimensional NMR spectra, mass spectrometry, and infrared spectrometry. And the molecular structures of 3a−c, 4a, and 4c have been determined by the single-crystal X-ray diffraction method. Furthermore, the detailed spectroscopic properties and catalytic activities of the complexes for the reduction of nitro compounds were discussed in terms of the modification of the coordination ligands to the center metal.

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“…N -Phosphanyl-1,2,4-triazol-5-ylidenes ( II ) and N -phosphanylimidazolin-2-ylidenes ( III ) were also reported to form dinuclear complexes (mode A ) with coinage metals. Recently, the Braunstein and Danopoulos groups reported novel diphosphanyl N-heterocyclic carbenes ( IV ), which formed multinuclear complexes with d 10 coinage metals. However, these N -phosphanyl-NHCs showed thermal unstability with rearrangement from the N-PR 2 to C-PR 2 with heating.…”

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confidence: 99%

4-Phosphino-1,2,3-triazol-5-ylidenes: Stable Bridging Ligands for Coinage Metal Complexes

et al. 2018

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Transition metal (Rh and Fe) complexes and main-group (Se and B) adducts with N,N′-diphosphanyl NHC ligands: a study of stereoelectronic properties

Cited by 17 publications

References 55 publications

Quantifying the Electronic and Steric Properties of 1,3-Imidazole-Based Mesoionic Carbenes (iMICs)

Quantifying the Electronic and Steric Properties of 1,3-Imidazole-Based Mesoionic Carbenes (iMICs)

Synthesis, Characterization, and Catalytic Activities of Palladium Complexes with Phenylene-Bridged Bis(thione) Ligands

4-Phosphino-1,2,3-triazol-5-ylidenes: Stable Bridging Ligands for Coinage Metal Complexes

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