Ligand-enforced geometric constraints and associated reactivity in p-block compounds

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 53(2), P. 764 - 792

Published: Dec. 15, 2023

This review presents a group-wise summary of ligand enforced non-VSEPR geometries in compounds the p-block elements and discusses emergent consequences for reactivity.

Language: Английский

---

Synthesis, Isolation, and Characterization of Two Cationic Organobismuth(II) Pincer Complexes Relevant in Radical Redox Chemistry

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(10), P. 5618 - 5623

Published: Feb. 28, 2023

Herein, we report the synthesis, isolation, and characterization of two cationic organobismuth(II) compounds bearing N,C,N pincer frameworks, which model crucial intermediates in bismuth radical processes. X-ray crystallography uncovered a monomeric Bi(II) structure, while SQUID magnetometry combination with NMR EPR spectroscopy provides evidence for paramagnetic S = 1/2 state. High-resolution multifrequency at X-, Q-, W-band enable precise assignment full g- 209Bi A-tensors. Experimental data DFT calculations reveal both complexes are metal-centered radicals little delocalization onto ligands.

Language: Английский

---

Calcium‐Ligand Cooperation Promoted Activation of N₂O, Amine, and H₂ as well as Catalytic Hydrogenation of Imines, Quinoline, and Alkenes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 27, 2024

Abstract Bond activation and catalysis using s‐block metals are of great significance. Herein, a series calcium pincer complexes with deprotonated side arms have been prepared pyridine‐based PNP PNN ligands. The were characterized by NMR X‐ray crystal diffraction. Utilizing the obtained complexes, unprecedented N 2 O metal‐ligand cooperation (MLC) involving dearomatization‐aromatization pyridine ligand was achieved, generating aromatized diazotate as products. Additionally, dearomatized able to activate N−H bond well reversibly H , offering an opportunity for catalytic hydrogenation various unsaturated molecules. DFT calculations applied analyze electronic structures synthesized explore possible reaction mechanisms. This study is important complement area MLC main‐group metal chemistry.

Language: Английский

---

Carbodicarbene Bismaalkene Cations: Unravelling the Complexities of Carbene versus Carbone in Heavy Pnictogen Chemistry

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(12), P. 6682 - 6690

Published: Dec. 9, 2020

We report a combined experimental and theoretical study on the first examples of carbodicarbene (CDC)-stabilized bismuth complexes, which feature low-coordinate cationic centers with C=Bi multiple-bond character. Monocations [(CDC)Bi(Ph)Cl][SbF6 ] (8) [(CDC)BiBr2 (THF)2 ][SbF6 (11), dications [(CDC)Bi(Ph)][SbF6 ]2 (9) [(CDC)BiBr(THF)3 ][NTf2 (12), trication [(CDC)2 Bi][NTf2 ]3 (13) have been synthesized via sequential halide abstractions from (CDC)Bi(Ph)Cl2 (7) (CDC)BiBr3 (10). Notably, exhibit C ⇉ Bi double dative bonds thus represent unprecedented bismaalkene cations. The synthesis these species highlights unique non-reductive route to C-Bi π-bonding CDC-[Bi] complexes (7-13) were compared related NHC-[Bi] (1, 3-6) show substantially different structural properties. Indeed, CDC ligand has remarkable influence overall stability resulting suggesting that is superior NHC in heavy pnictogen chemistry.

Language: Английский

---

Lewis Superacidic Heavy Pnictaalkene Cations: Comparative Assessment of Carbodicarbene-Stibenium and Carbodicarbene-Bismuthenium Ions

Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(46), P. 18640 - 18652

Published: Nov. 9, 2022

We report a comprehensive assessment of Lewis acidity for series carbone-stibenium and -bismuthenium ions using the Gutmann-Beckett (GB) method. These new antimony bismuth cations have been synthesized by halide abstractions from (CDC)PnBr3 [(pyCDC)PnBr2][Br] (CDC = carbodicarbene; Pn Sb or Bi; py pyridyl). The reaction (CDC)SbBr3 (1) with one two equivalents AgNTf2 (NTf2 bis(trifluoromethanesulfonyl)imide) AgSbF6 gives stibaalkene mono- dications form [(CDC)SbBr3-n][A]n (2-4; n 1,2; A NTf2 SbF6). trication [(CDC)2Sb][NTf2]3 (5) was also isolated collectively these molecules fill gap among cationic pnictaalkenes. are compared to related CDC-bismaalkene complexes 6-9. With goal preparing highly acidic compounds, tridentate bis(pyridine)carbodicarbene (pyCDC) used as ligand access (10, 12) trications [(pyCDC)Pn][NTf2]3 (Pn (11), Bi (13)), forgoing need second CDC in synthesis 5. bonding situation is elucidated through electron density energy decomposition analyses combination natural orbital chemical valence theory. In each complex, there exists CDC-Pn double interaction, consisting strong σ-bond weaker π-bond, whereby π-bond gradually strengthens increase charge complex. Notably, [(CDC)SbBr][NTf2]2 (4) has an acceptor number (AN) (84) that comparable quintessential acids such BF3, tricationic pnictaalkene 11 13 exhibit ANs 109 Sb) 84 Bi), respectively, which highest values reported any cation. Moreover, calculated fluoride ion affinities (FIAs) 99.8 94.3 kcal/mol, larger than SbF5 (85.1 kcal/mol), suggest superacids.

Language: Английский

---

Mechanism of the Aryl–F Bond-Forming Step from Bi(V) Fluorides

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(32), P. 14489 - 14504

Published: Aug. 3, 2022

In this article, we describe a combined experimental and theoretical mechanistic investigation of the C(sp

Language: Английский

---

Dihydrogen and Ethylene Activation by a Sterically Distorted Distibene

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 2, 2023

Herein, we report the synthesis of a sterically distorted distibene ([4]2 ) and its transition-metal-like reactivity towards two fundamental feedstock chemicals: H2 ethylene. Although [4]2 exhibits an unusually long Sb=Sb distance noticeable backbone distortion in solid state, NMR data suggest that remains predominantly as dimer solution, even at high temperatures. However, it was proposed elusive toward ethylene results from reversible dissociation into transient stibinidene ([4]), which could be observed by spectroscopic techniques.

Language: Английский

---

Stabilizing Monoatomic Two-Coordinate Bismuth(I) and Bismuth(II) Using a Redox Noninnocent Bis(germylene) Ligand

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(9), P. 6025 - 6036

Published: Feb. 26, 2024

The formation of isolable monatomic BiI complexes and BiII radical species is challenging due to the pronounced reducing nature metallic bismuth. Here, we report a convenient strategy tame atoms by taking advantage redox noninnocent character new chelating bis(germylene) ligand. remarkably stable novel cation complex 4, supported bis(iminophosphonamido-germylene)xanthene ligand [(P)GeII(Xant)GeII(P)] 1, [(P)GeII(Xant)GeII(P) = Ph2P(NtBu)2GeII(Xant)GeII(NtBu)2PPh2, Xant 9,9-dimethyl-xanthene-4,5-diyl], was synthesized two-electron reduction cationic BiIIII2 precursor 3 with cobaltocene (Cp2Co) in molar ratio 1:2. Notably, owing germylene moieties, positive charge 4 migrates one Ge ligand, giving rise germylium(germylene) as suggested DFT calculations X-ray photoelectron spectroscopy (XPS). Likewise, migration results bis(germylium)BiIIII2 complex. delocalization engenders much higher stability comparison an isoelectronic two-coordinate Pb0 analogue (plumbylone; decomposition below −30 °C). Interestingly, 4[BArF] undergoes reversible single-electron transfer (SET) reaction (oxidation) afford 5 5[BArF]2. According electron paramagnetic resonance (EPR) spectroscopy, unpaired predominantly resides at atom. Extending reactivity 4[OTf] employing AgOTf MeOTf affords BiIII(OTf)2 7 BiIIIMe 8, respectively, demonstrating high nucleophilic 4.

Language: Английский

---

Deoxygenation of Nitrous Oxide and Nitro Compounds Using Bis(N‐Heterocyclic Silylene)Amido Iron Complexes as Catalysts

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(7)

Published: Nov. 12, 2021

Herein, we report the efficient degradation of N2 O with a well-defined bis(silylene)amido iron complex as catalyst. The deoxygenation using silanone 4 catalyst and pinacolborane (HBpin) sacrificial reagent proceeds smoothly at 50 °C to form , H2 (pinB)2 O. Mechanistic studies suggest that iron-silicon cooperativity is key this catalytic transformation, which involves activation, H atom transfer, release oxygenation boron sites. This approach has been further developed enable reductions nitro compounds, producing amino-boranes good functional-group tolerance excellent chemoselectivity.

Language: Английский

---

Three-Component Coupling of Acyl Fluorides, Silyl Enol Ethers, and Alkynes by P(III)/P(V) Catalysis

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(44), P. 18394 - 18399

Published: Nov. 1, 2021

We report herein on the phosphine-catalyzed hydrovinylation reaction by three-component coupling of acyl fluorides, silyl enol ethers, and alkynoates. The key to success is formal transmetalation between pentacoordinate P(V) species (i.e., fluorophosphorane) a ether, which allows for C–C bond formation polarity-mismatched sites. that cannot be attained even transition metal catalysis accomplished P(III)/P(V) manifold.

Language: Английский

---