Synthesis of (POCOP)Co(Ph)(X) Pincer Complexes and Observation of Aryl–Aryl Reductive Elimination Involving the Pincer Aryl

2018 ◽  
Vol 37 (21) ◽  
pp. 3803-3812 ◽  
Author(s):  
Bryan J. Foley ◽  
Chandra Mouli Palit ◽  
Samuel D. Timpa ◽  
Oleg V. Ozerov
Keyword(s):  
Reductive Elimination ◽  
Pincer Complexes

scholarly journals Carbon–sulfur bond formation by reductive elimination of gold(iii) thiolates

2018 ◽  
Vol 47 (18) ◽  
pp. 6333-6343 ◽  
Author(s):  
Lucy Currie ◽  
Luca Rocchigiani ◽  
David L. Hughes ◽  
Manfred Bochmann
Keyword(s):  
Bond Formation ◽  
Reductive Elimination ◽  
Pincer Complexes ◽  
Elimination Reactions ◽  
Sulfur Bond

Thiols were found to cleave Au–C bonds in (C^N^C)gold(iii) pincer complexes and to induce C–S reductive elimination reactions, to give aryl thioethers.

scholarly journals Comparing the Acidity of (R3P)2BH-Based Donor Groups in Iridium Pincer Complexes

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 61 ◽  
Author(s):  
Leon Maser ◽  
Christian Schneider ◽  
Lukas Alig ◽  
Robert Langer
Keyword(s):  
Secondary Amine ◽  
Quantum Chemical ◽  
Reductive Elimination ◽  
Pincer Complexes ◽  
Donor Group ◽  
Initial Product ◽  
Square Planar ◽  
Neutral Ligands ◽  
Stretching Vibrations ◽  
Iridium Pincer Complexes

In the current manuscript, we describe the reactivity of a series of iridium(III) pincer complexes with the general formulae [(PEP)IrCl(CO)(H)]n (n = +1, +2) towards base, where PEP is a pincer-type ligand with different central donor groups, and E is the ligating atom of this group (E = B, C, N). The donor groups encompass a secondary amine, a phosphine-stabilised borylene and a protonated carbodiphosphorane. As all ligating atoms E exhibit an E–H bond, we addressed the question of wether the coordinated donor group can be deprotonated in competition to the reductive elimination of HCl from the iridium(III) centre. Based on experimental and quantum chemical investigations, it is shown that the ability for deprotonation of the coordinated ligand decreases in the order of (R3P)2CH+ > R2NH > (R3P)2BH. The initial product of the reductive elimination of HCl from [(PBP)IrCl(CO)(H)]n (1c), the square planar iridium(I) complex, [(PBP)Ir(CO)]+ (3c), was found to be unstable and further reacts to [(PBP)Ir(CO)2]+ (5c). Comparing the C–O stretching vibrations of the latter with those of related complexes, it is demonstrated that neutral ligands based on tricoordinate boron are very strong donors.

Reversible Oxidative-Addition and Reductive-Elimination of Thiophene from a Titanium Complex and Its Thermally-Induced Hydrodesulfurization Chemistry

2019 ◽  
Author(s):  
Alejandra Gomez-Torres ◽  
J. Rolando Aguilar-Calderón ◽  
Carlos Saucedo ◽  
Aldo Jordan ◽  
Alejandro J. Metta-Magaña ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Thiophene Ring ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Thermally Induced ◽  
Titanium Complex

<p>The masked Ti(II) synthon (<sup>Ket</sup>guan)(<i>η</i><sup>6</sup>-Im<sup>Dipp</sup>N)Ti (<b>1</b>) oxidatively adds across thiophene to give ring-opened (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti[<i>κ</i><sup>2</sup>-<i>S</i>(CH)<sub>3</sub><i>C</i>H] (<b>2</b>). Complex <b>2</b> is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate <b>1</b> – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from <b>2</b>. Finally, pressurizing solutions of <b>2 </b>with H<sub>2</sub> (150 psi) at 80 °C leads to the hydrodesulfurization of thiophene to give the Ti(IV) sulfide (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti(S) (<b>3</b>) and butane. </p>

S(IV)–Mediated Unsymmetrical Heterocycle Cross-Couplings

2019 ◽  
Author(s):  
Min Zhou ◽  
Jet Tsien ◽  
Tian Qin
Keyword(s):  
Cross Coupling ◽  
Reductive Elimination ◽  
Facile Synthesis ◽  
Trigonal Bipyramidal

<p>Herein we report a sulfur (IV) mediated cross-coupling for facile synthesis of heteroaromatic substrates. Addition of heteroaryl nucleophiles onto a simple, readily-accessible alkyl sulfinyl (IV) chloride allows formation of a trigonal bipyramidal sulfurane intermediate. Reductive elimination therefrom provides bis-heteroaryl products in a practical and efficient fashion. <br></p>

Effect of Hydrated Metal Salts on the Coordination Product of Cobalt(II) halide and PNP Type Ligand, 2,6-bis(di-tertbutylphosphinomethyl) pyridine

2018 ◽  
Author(s):  
Tasneem Siddiquee ◽  
Abdul Goni
Keyword(s):  
Metal Salts ◽  
Molar Ratio ◽  
Pincer Complexes ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Pincer Ligand ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Distorted Tetrahedral Geometry ◽  
Cobalt Center

Chemical treatment of CoX<sub>2</sub><b><sup>. </sup></b>6H<sub>2</sub>O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-<i>tert</i>-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.

Carbon-Heteroatom Cross-Coupling via an Electronically Excited Nickel (II) Complex

2019 ◽  
Author(s):  
Randolph Escobar ◽  
Jeffrey Johannes
Keyword(s):  
Energy Transfer ◽  
Functional Groups ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
General Methodology ◽  
Cross Coupling Reactions ◽  
Electronically Excited ◽  
Energy Transfer Pathway

<div>While carbon-heteroatom cross coupling reactions have been extensively studied, many methods are specific and</div><div>limited to a set of substrates or functional groups. Reported here is a method that allows for C-O, C-N and C-S cross coupling reactions under one general methodology. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel (II) complex, is responsible for the key reductive elimination step that couples aryl halides to 1° and 2° alcohols, anilines, thiophenols, carbamates and sulfonamides.</div>

scholarly journals Force-modulated reductive elimination from platinum(ii) diaryl complexes

2021 ◽  
Author(s):  
Yichen Yu ◽  
Chenxu Wang ◽  
Liqi Wang ◽  
Cai-Li Sun ◽  
Roman Boulatov ◽  
...  
Keyword(s):  
Transition State ◽  
Reductive Elimination ◽  
Mechanical Force ◽  
Elimination Reactions

The influence of mechanical force on the rates of model reductive elimination reactions depends on the structure of the force-transducing ligand and provides a measure of geometry changes upon reaching the transition state.

Novel meta-Benzothiazole and Benzimidazole Functionalised POCOP-Ni(II) Pincer Complexes as Efficient Catalysts in the Production of Diarylketones.

2021 ◽  
Author(s):  
Antonio Aldair Castillo-García ◽  
González-Sebastián Lucero ◽  
Leticia Lomas-Romero ◽  
Simon Hernandez-Ortega ◽  
Ruben Alfredo Toscano ◽  
...  
Keyword(s):  
Pincer Complexes ◽  
Aryl Ring

The synthesis of four novel non-symmetric Ni(II)-POCOP pincer complexes meta-functionalized with either benzothiazole or benzimidazole at the central aryl ring is described. All complexes were fully characterised in solution by...

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