Pt(II)-Chiral Diene-Catalyzed Enantioselective Formal [4+2] Cycloaddition Initiated by C-C Bond Cleavage and Elucidation of a Pt(II)/(IV) Cycle by DFT Calculations

2021 ◽  
Author(s):  
Takanori Shibata ◽  
Natsumi Shiozawa ◽  
Shun Nishibe ◽  
Hideaki Takano ◽  
Satoshi Maeda
Keyword(s):  
Dft Calculations ◽  
Bond Cleavage

A chiral Pt(II) complex was readily prepared from [PtCl2(C2H4)]2 and Hayashi’s diene. Its dicationic derivative efficiently catalyzed a formal intramolecular [4+2] cycloaddition of biphenylenes possessing substituted arylalkynes tethered by an...

scholarly journals Heterolytic bond activation at gold: evidence for gold(iii) H–B, H–Si complexes, H–H and H–C cleavage

2019 ◽  
Vol 10 (9) ◽  
pp. 2633-2642 ◽  
Author(s):  
Luca Rocchigiani ◽  
Peter H. M. Budzelaar ◽  
Manfred Bochmann
Keyword(s):  
Dft Calculations ◽  
Bond Activation ◽  
Bond Cleavage

Gold(iii) forms spectroscopically detectable H–B and H–Si σ-complexes; experiments and DFT calculations demonstrate heterolytic H–Si, H–H and H–C bond cleavage.

scholarly journals Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes

2021 ◽  
Author(s):  
Stefan Weber ◽  
Luis F. Veiros ◽  
Karl Kirchner
Keyword(s):  
Dft Calculations ◽  
Precious Metal ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Migratory Insertion ◽  
Earth Abundant ◽  
First Time

<div>For the first time, an efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth abundant non-precious metal catalyst. The pre-catalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid C-H bond cleavage of the alkyne forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes yields selectively head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1-2 mol %. A mechanism based on DFT calculations is presented.</div><div><br></div>

scholarly journals Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes

2021 ◽  
Author(s):  
Stefan Weber ◽  
Luis F. Veiros ◽  
Karl Kirchner
Keyword(s):  
Dft Calculations ◽  
Precious Metal ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Migratory Insertion ◽  
Earth Abundant ◽  
First Time

<div>For the first time, an efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth abundant non-precious metal catalyst. The pre-catalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid C-H bond cleavage of the alkyne forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes yields selectively head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1-2 mol %. A mechanism based on DFT calculations is presented.</div><div><br></div>

scholarly journals Antibacterial Activity of Amidodithiophosphonato Nickel(II) Complexes: An Experimental and Theoretical Approach

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2052 ◽  
Author(s):  
Enrico Podda ◽  
Massimiliano Arca ◽  
Giulia Atzeni ◽  
Simon J. Coles ◽  
Antonella Ibba ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Dft Calculations ◽  
Density Functional ◽  
Bond Cleavage ◽  
Nickel Complexes ◽  
Functional Theory ◽  
Gram Negative

The reactions of 2,4-bis(4-methoxyphenyl)-1,3-dithio-2,4-diphosphetane-2,4-disulfide (Lawesson’s Reagent, LR) with benzylamine (BzNH2) and 4-phenylbutylamine (PhBuNH2) yield benzylammonium P-(4-methoxyphenyl)-N-benzyl-amidodithiophosphonate (BzNH3)(BzNH-adtp) and 4-phenylbutylammonium P-(4-methoxyphenyl)-N-(4-phenylbutyl)-amidodithiophosphonate (PhBuNH3)(PhBuNH-adtp). The relevant nickel complexes [Ni(BzNH-adtp)2] and [Ni(PhBuNH-adtp)2] and the corresponding hydrolysed derivatives (BzNH3)2[Ni(dtp)2] and (PhBuNH3)2[Ni(dtp)2] were prepared and fully characterized. The antimicrobial activity of the aforementioned amidodithiophosphonates against a set of Gram-positive and Gram-negative pathogen bacteria was evaluated, and [Ni(BzNH-adtp)2] and [Ni(PhBuNH-adtp)2] showed antiproliferative activity towards Staphylococcus aureus and Staphylococcus haemolyticus strains. density functional theory (DFT) calculations were performed to shed some light on the activity of reported compounds related to their tendency towards P–N bond cleavage.

scholarly journals Combined the Photocatalysis and Fenton-like Reaction to Efficiently Remove Sulfadiazine in Water Using g-C3N4/Ag/γ-FeOOH: Insights Into the Degradation Pathway From Density Functional Theory

2021 ◽  
Vol 9 ◽  
Author(s):  
Yangchen Zhu ◽  
Furong Zhao ◽  
Fei Wang ◽  
Beihai Zhou ◽  
Huilun Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Separation Efficiency ◽  
Bond Cleavage ◽  
Degradation Pathway ◽  
Environmental Pollutant ◽  
Functional Theory ◽  
Catalytic Material ◽  
Degradation Effect

Sulfadiazine (SDZ) is a common antibiotic pollutant in wastewater. Given that it poses a risk as an environmental pollutant, finding effective ways to treat it is important. In this paper, the composite catalytic material g-C3N4/Ag/γ-FeOOH was prepared, and its degradation performance was studied. g-C3N4/Ag/γ-FeOOH had a superior degradation effect on SDZ than g-C3N4 and γ-FeOOH. Compared with different g-C3N4 loadings and different catalyst dosages (5, 10, 25, and 50 mg/L), 2 mg/L g-C3N4/Ag/γ-FeOOH with a g-C3N4 loading of 5.0 wt% has the highest degradation promotion rate for SDZ, reaching up to 258.75% at 600 min. In addition, the photocatalytic enhancement mechanism of the catalyst was studied. Density functional theory (DFT) calculations indicated that the enhancement of photocatalytic activity was related to the narrowing of the forbidden band and the local electron density of the valence band. The bandgap of the catalyst was gradually narrowed from 2.7 to 1.05 eV, which can increase the light absorption intensity and expand the absorption edge. The density of states diagram showed that the local resonance at the interface could effectively improve the separation efficiency of e−-h+ pairs. Four degradation paths of SDZ were speculated based on DFT calculations. The analysis confirmed that the degradation path of SDZ primarily included Smiles-type rearrangement, SO2 extrusion, and S-N bond cleavage processes.

Brønsted base-catalyzed annulation of allyl ketones and alkynyl 1,2-diketones

2018 ◽  
Vol 54 (34) ◽  
pp. 4266-4269 ◽  
Author(s):  
Xiangwen Kong ◽  
Jinshuai Song ◽  
Jian Liu ◽  
Miao Meng ◽  
Shuang Yang ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Bond Cleavage ◽  
Aldol Reaction ◽  
Mild Conditions ◽  
Brønsted Base ◽  
Selective Addition

The Cs2CO3-catalyzed reaction of allyl ketones and alkynyl 1,2-diketones affords a series of 2-acyloxycyclopent-3-enones under mild conditions. A unique α-selective addition/aldol reaction/C–C bond cleavage mechanism was proposed and supported by DFT calculations.

scholarly journals Complete σ* intramolecular aromatic hydroxylation mechanism through O2 activation by a Schiff base macrocyclic dicopper(I) complex

2013 ◽  
Vol 9 ◽  
pp. 585-593 ◽  
Author(s):  
Albert Poater ◽  
Miquel Solà
Keyword(s):  
Schiff Base ◽  
Proton Transfer ◽  
Dft Calculations ◽  
Reaction Pathway ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Subsequent Reaction ◽  
O2 Activation ◽  
Aromatic Carbon ◽  
Aromatic Hydroxylation

In this work we analyze the whole molecular mechanism for intramolecular aromatic hydroxylation through O2 activation by a Schiff hexaazamacrocyclic dicopper(I) complex, [CuI 2(bsH2m)]2+. Assisted by DFT calculations, we unravel the reaction pathway for the overall intramolecular aromatic hydroxylation, i.e., from the initial O2 reaction with the dicopper(I) species to first form a CuICuII-superoxo species, the subsequent reaction with the second CuI center to form a μ-η2:η2-peroxo-CuII 2 intermediate, the concerted peroxide O–O bond cleavage and C–O bond formation, followed finally by a proton transfer to an alpha aromatic carbon that immediately yields the product [CuII 2(bsH2m-O)(μ-OH)]2+.

Mechanistic insight into conjugated N–N bond cleavage by Rh(iii)-catalyzed redox-neutral C–H activation of pyrazolones

2015 ◽  
Vol 13 (30) ◽  
pp. 8251-8260 ◽  
Author(s):  
Weirong Wu ◽  
Yuxia Liu ◽  
Siwei Bi
Keyword(s):  
Dft Calculations ◽  
Bond Cleavage ◽  
Mechanistic Insight ◽  
Insight Into

DFT calculations are performed to understand the conjugated N–N bond cleavage by Rh(iii)-catalyzed redox-neutral C–H activation of pyrazolones with PhCCPh.

Probing enantioselectivity in rhodium-catalyzed Si–C bond cleavage to construct silicon-stereocenters: a theoretical study

2019 ◽  
Vol 9 (3) ◽  
pp. 646-651 ◽  
Author(s):  
Zhaoyuan Yu ◽  
Tao Zhang ◽  
Ruopeng Bai ◽  
Yu Lan
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Theoretical Study ◽  
Bond Cleavage ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Functional Theory ◽  
Elimination Process

Density functional theory (DFT) calculations indicate that favorable oxidative addition/reductive elimination process from arylrhodium complex determines the enantioselectivity.

Nickel-catalyzed Homo-coupling of Aryl Ethers with Magnesium Anthracene Reductant

Synthesis ◽  
2021 ◽  
Author(s):  
Vishal Kumar Rawat ◽  
Kosuke Higashida ◽  
Masaya Sawamura
Keyword(s):  
Dft Calculations ◽  
Bond Cleavage ◽  
Low Cost ◽  
Coupling Reaction ◽  
Reducing Agent ◽  
Aryl Ether ◽  
Bimetallic System ◽  
Cleavage Reactions ◽  
Aryl Ethers

Nickel-catalyzed reductive homo-coupling of aryl ethers has been achieved with Mg(anthracene)(thf)3 as a readily available low-cost reductant. DFT calculations provided a rationale for the specific efficiency of the diorganomagnesium-type two-electron reducing agent. The calculations showed that the dianionic anthracene-9,10-diyl ligand reduces the two aryl ether substrates resulting in the homo-coupling reaction through supplying the electrons to the Ni-Mg bimetallic system to form organomagnesium nickel(0)-ate complexes, which cause two sequential C–O bond cleavage reactions. The calculations also showed cooperative actions of Lewis-acidic magnesium atoms and electron-rich nickel atoms in the C–O cleavage reactions.

Sign in / Sign up

Export Citation Format

Share Document