scholarly journals Metal control of selectivity in acetate-assisted C–H bond activation: an experimental and computational study of heterocyclic, vinylic and phenylic C(sp2)–H bonds at Ir and Rh

2014 ◽  
Vol 5 (6) ◽  
pp. 2340-2346 ◽  
Author(s):  
Kevin J. T. Carr ◽  
David L. Davies ◽  
Stuart A. Macgregor ◽  
Kuldip Singh ◽  
Barbara Villa-Marcos
Keyword(s):  
Bond Activation ◽  
Computational Study ◽  
Metal Catalyst ◽  
Kinetic Control ◽  
Dft Studies ◽  
Thermodynamic Control

Experimental and DFT studies show the selectivity of C–H bond activation at [MCl2Cp*]2 (M = Ir, Rh) species can be controlled by the choice of metal catalyst, reflecting kinetic control at M = Ir and thermodynamic control at M = Rh.

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

2020 ◽  
Author(s):  
Rui Guo ◽  
Xiaotian Qi ◽  
Hengye Xiang ◽  
Paul Geaneoates ◽  
Ruihan Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Biologically Active ◽  
Dft Studies ◽  
Thermodynamic Control ◽  
Important Goal ◽  
Peptide Bonds ◽  
Metal Free ◽  
Vinyl Cation ◽  
E And Z Isomers ◽  
Vinyl Fluorides

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

Identifying the preferential pathways of CO2 capture and hydrogenation to methanol over Mn(I)-PNP catalyst: A computational study

2021 ◽  
Author(s):  
Shyama Charan Mandal ◽  
Biswarup Pathak
Keyword(s):  
Density Functional Theory ◽  
Co2 Capture ◽  
Density Functional ◽  
Computational Study ◽  
Co2 Hydrogenation ◽  
Dft Studies ◽  
Functional Theory ◽  
Preferential Pathways

CO2 hydrogenation to CH3OH is a crucial conversion for several purposes. Density functional theory (DFT) studies have been performed to explore the mechanistic pathways of newly reported CO2 capture and...

Insights into hydrogen bond donor promoted fixation of carbon dioxide with epoxides catalyzed by ionic liquids

2015 ◽  
Vol 17 (8) ◽  
pp. 5959-5965 ◽  
Author(s):  
Mengshuai Liu ◽  
Kunqi Gao ◽  
Lin Liang ◽  
Fangxiao Wang ◽  
Lei Shi ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Ionic Liquids ◽  
Bond Activation ◽  
Cycloaddition Reaction ◽  
Dft Studies ◽  
Hydrogen Bond Donor ◽  
Fixation Of Carbon Dioxide

Experimental and DFT studies demonstrated that additional EG could cooperate with ILs to facilitate the cycloaddition reactionviahydrogen bond activation.

Novel Intramolecular CAryl–S Bond Activation by an Electron Rich, Ring-Expanded-NHC-Rh centre: A Combined Experimental and DFT Study

2011 ◽  
Vol 64 (8) ◽  
pp. 1141 ◽  
Author(s):  
Abeer Binobaid ◽  
Kingsley J. Cavell ◽  
Mikhail S. Nechaev ◽  
Benson M. Kariuki
Keyword(s):  
Bond Activation ◽  
Reaction Pathway ◽  
Heterocyclic Carbenes ◽  
Dft Study ◽  
Dft Studies ◽  
X Ray ◽  
Carbene Complex ◽  
Donor Capacity ◽  
Insight Into ◽  
Sulfur Bond

The reaction of (o-MeSPh)-N-functionalized tetrahydropyrimidinium salts with KN(SiMe3)2 and [Rh(COD)Cl]2 in THF leads to the formation of a novel dimeric RhIII bis-carbene complex. The reaction involves the unexpected cleavage/oxidative addition of the aryl-sulfur bond to give dimeric metallated RhIII with bridging MeS< moieties. This unusual reaction is probably a consequence of the sterically imposing structure and strong donor capacity of ring-expanded N-heterocyclic carbenes (RE-NHCs). An X-ray structure of the [(Ph,DIPP-NHC)Rh(Cl)(SMe)2] product complex has been obtained, and DFT studies were undertaken to gain an insight into the reaction pathway.

Experimental and Theoretical Investigation of the Reaction of Secondary Amines with Maleic Anhydride

2017 ◽  
Vol 70 (12) ◽  
pp. 1247 ◽  
Author(s):  
Manjinder Kour ◽  
Raakhi Gupta ◽  
Raj K. Bansal
Keyword(s):  
Maleic Anhydride ◽  
Carbonyl Group ◽  
Carbonyl Compounds ◽  
Secondary Amines ◽  
Kinetic Control ◽  
Thermodynamic Control ◽  
Carbonyl Carbon ◽  
Fukui Functions ◽  
Unsaturated Carbonyl Compound ◽  
Condensed Fukui Functions

The reaction of secondary amines, namely 1-methylpiperazine, pyrrolidine, morpholine, 2-methylpiperidine, and diethylamine, with maleic anhydride has been investigated experimentally and theoretically at the DFT level. Under kinetic control, i.e. at −78°C or −15°C, amines add across the C=O functionality exclusively and the initially formed addition products isomerize to the corresponding N-substituted maleimic acid derivatives. In contrast to the acyclic α,β-unsaturated carbonyl compounds, amine does not add across the C=C functionality in maleic anhydride even under thermodynamic control. This behaviour of maleic anhydride can be rationalized on the basis of the local condensed Fukui functions, which reveal that the carbonyl carbon atoms in maleic anhydride are much harder than in an acyclic α,β-unsaturated carbonyl compound, such as acrolein. This prompts the amines to attack the carbonyl group in maleic anhydride exclusively.

Helicity control in the synthesis of helicenes and related compounds

2006 ◽  
Vol 78 (2) ◽  
pp. 495-499 ◽  
Author(s):  
Ivo Starý ◽  
Irena G. Stará ◽  
Zuzana Alexandrová ◽  
Petr Sehnal ◽  
Filip Teplý ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Kinetic Control ◽  
Thermodynamic Control ◽  
Further Development ◽  
Related Compounds

Asymmetric synthesis of helicenes and their congeners has been demonstrated to rely either on enantioselective Ni0/PR3*-catalyzed [2+2+2] cycloisomerization of triynes or on diastereoselective CoI-catalyzed [2+2+2] cycloisomerization of chiral triynes. The former approach providing tetrahydrohelicenes in a nonracemic form requires further development as moderate enantioselectivities (up to 54 % ee) have so far been achieved under kinetic control. The latter approach affording helicene-like structures in a diastereomerically enriched form allows for reaching good to excellent diastereoselectivities (up to 100:0) under thermodynamic control.

Selective C−C vs C−H Bond Activation by Rhodium(I) PCP Pincer Complexes. A Computational Study

2000 ◽  
Vol 122 (29) ◽  
pp. 7095-7104 ◽  
Author(s):  
Andreas Sundermann ◽  
Olivier Uzan ◽  
David Milstein ◽  
Jan M. L. Martin
Keyword(s):  
Bond Activation ◽  
Computational Study ◽  
Pincer Complexes ◽  
Pcp Pincer

scholarly journals QUANTUM CHEMITRY STUDY ON STRUCTURES, ACTIVITIES AND REACTIONS OF ONIUM-BORONIUM DICATIONS

2010 ◽  
Vol 13 (2) ◽  
pp. 45-52
Author(s):  
Thanh Tho Bui ◽  
Tran Thi Bao Vo
Keyword(s):  
Activation Energy ◽  
Intrinsic Reaction Coordinate ◽  
Kinetic Control ◽  
Ab Initio Methods ◽  
Thermodynamic Control ◽  
Imaginary Frequency ◽  
Theoretical Investigations ◽  
Transition Structures ◽  
Frequency Calculation ◽  
Energy Activation

This paper provides information about theoretical investigations of structures of onium-boronium dications X+BH3+, X+BH5+; (X= NH3, PH3, H2O, H2S) and some reactions of them in thermodynamic control and kinetic control. Two kinds of reactions studied are complexation of onium-boronium dications X+BH3+ with H2 leading to X+BH5+ and deprotonation of X+BH5+ to give X+BH4. The similar studies with boronium ion analog BH4+ and BH6+ is carried out and results obtained pointed out that the eletrophility of onium-boronium dications is more stronger than that of boronium ion: onium-boronium dications X+BH3+, X+BH5+ are superelectrophiles. The structures of onium-boronium dications and boronium ions are optimized by using ab initio methods at the MP2/6-311+G** level of Gaussian 03W, revision B.04 and represented with Gaussview 3.0. Frequency calculation is performed to assure the obtained structures corresponding to minimun energies and have no any imaginary frequency. The transition structures are calculated and verified due to Intrinsic Reaction Coordinate Calculations. The properties of structures, as MP2 energy, Gibbs free energy, activation energy are also examined.

Unexpected Stability of CO-Coordinated Palladacycle in Bidentate Auxiliary Directed C(sp3)–H Bond Activation: A Combined Experimental and Computational Study

2019 ◽  
Vol 38 (9) ◽  
pp. 2022-2030 ◽  
Author(s):  
Yi Jiang ◽  
Shuo-Qing Zhang ◽  
Fei Cao ◽  
Jiao-Xia Zou ◽  
Jing-Lu Yu ◽  
...  
Keyword(s):  
Bond Activation ◽  
Computational Study

Unveiling the potential of scandium complexes for methane C–H bond activation: a computational study

2019 ◽  
Vol 43 (31) ◽  
pp. 12257-12263 ◽  
Author(s):  
Ana Paula de Lima Batista ◽  
Antonio G. S. de Oliveira-Filho ◽  
Ataualpa A. C. Braga
Keyword(s):  
Bond Activation ◽  
Computational Study ◽  
Mild Conditions

Sc(i) complexes activate methane C–H bonds under mild conditions.

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