Oxidative addition of monosilanes to planar iridium(I) complexes and carbonylation of the resulting adducts

1977 ◽  
Vol 30 (6) ◽  
pp. 1201 ◽  
Author(s):  
MA Bennett ◽  
R Charles ◽  
PJ Fraser
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Steric Effects ◽  
Ambient Conditions ◽  
Tetragonal Pyramidal ◽  
Group 5 ◽  
Electronic And Steric Effects

Silanes [R3SiH; R3 = Cl3, MeCl2, (EtO)3, Ph3] undergo irreversible oxidative addition to planar iridium(I) complexes IrClL3 (L = PPh3, PMePh2 or AsPh3) to give silyliridium(III) hydrides IrHCl(SiR3)Ln (n = 2 or 3). The yellow, five-coordinate, probably tetragonal pyramidal complexes(n = 2) are formed mainly when L = PPh3 or AsPh3, and also in the case of L = PmePh2, R = Ph, whereas the colourless, six-coordinate, presumably octahedral adducts are formed predominantly when L = PMePh2. Both five- and six-coordinate adducts can be isolated from the addition of dichloro(methyl)silane to IrCl(AsPh3)3. Most of the adducts react with carbon monoxide under ambient conditions to give silyliridium(III) hydrido carbonyls, IrHCl(SiR3)(CO)L2, which may undergo partial or complete reductive elimination to IrCl(CO)L2 and R3SiH; the ease with which this occurs depends on L (PPh3 > PMePh2 > AsPh3) and on R3 [Ph3 > (EtO)3 > Cl3 ≈ MeCl2]. The reactions of silanes with IrClL3, RhClL3 and IrCl(CO)(PPh3)2 are compared, and the trends observed in the case of IrClL3 are discussed in terms of electronic and steric effects in the silyl and Group 5 donors. Structural assignments for the new complexes are based on i.r., far-i.r. and 1H N.M.R. data.

Electronic and Steric Effects on the Reductive Elimination of Diaryl Ethers from Palladium(II)

2003 ◽  
Vol 22 (13) ◽  
pp. 2775-2789 ◽  
Author(s):  
Grace Mann ◽  
Quinetta Shelby ◽  
Amy H. Roy ◽  
John F. Hartwig
Keyword(s):  
Reductive Elimination ◽  
Steric Effects ◽  
Diaryl Ethers ◽  
Electronic And Steric Effects

A dual light-driven palladium catalyst: Breaking the barriers in carbonylation reactions

Science ◽  
2020 ◽  
Vol 368 (6488) ◽  
pp. 318-323 ◽  
Author(s):  
Gerardo M. Torres ◽  
Yi Liu ◽  
Bruce A. Arndtsen
Keyword(s):  
Bond Cleavage ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Inherent Limitation ◽  
Carbonyl Derivatives ◽  
Palladium Catalyzed ◽  
Light Excitation ◽  
Metal Catalyzed

Transition metal–catalyzed coupling reactions have become one of the most important tools in modern synthesis. However, an inherent limitation to these reactions is the need to balance operations, because the factors that favor bond cleavage via oxidative addition ultimately inhibit bond formation via reductive elimination. Here, we describe an alternative strategy that exploits simple visible-light excitation of palladium to drive both oxidative addition and reductive elimination with low barriers. Palladium-catalyzed carbonylations can thereby proceed under ambient conditions, with challenging aryl or alkyl halides and difficult nucleophiles, and generate valuable carbonyl derivatives such as acid chlorides, esters, amides, or ketones in a now-versatile fashion. Mechanistic studies suggest that concurrent excitation of palladium(0) and palladium(II) intermediates is responsible for this activity.

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>

Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

2019 ◽  
Author(s):  
Rebecca Lindsey ◽  
Nir Goldman ◽  
Laurence E. Fried ◽  
Sorin Bastea
Keyword(s):  
Carbon Monoxide ◽  
Molecular System ◽  
Interaction Model ◽  
System Size ◽  
Single Atom ◽  
Reactive System ◽  
Extreme Conditions ◽  
Ambient Conditions ◽  
Molecular Systems ◽  
Three Body

<p>The interatomic Chebyshev Interaction Model for Efficient Simulation (ChIMES) is based on linear combinations of Chebyshev polynomials describing explicit two- and three-body interactions. Recently, the ChIMES model has been developed and applied to a molten metallic system of a single atom type (carbon), as well as a non-reactive molecular system of two atom types at ambient conditions (water). Here, we continue application of ChIMES to increasingly complex problems through extension to a reactive system. Specifically, we develop a ChIMES model for carbon monoxide under extreme conditions, with built-in transferability to nearby state points. We demonstrate that the resulting model recovers much of the accuracy of DFT while exhibiting a 10<sup>4</sup>increase in efficiency, linear system size scalability and the ability to overcome the significant system size effects exhibited by DFT.</p>

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