scholarly journals THEORETICAL STUDY OF THE REACTION MECHANISM 1,2-ETHANEDIIOL WITH 1,3-DICHLOROPROPENE

2020 ◽  
Vol 2018 (1) ◽  
pp. 68-77
Author(s):  
Elena Chirkina ◽  
Leonid Krivdin ◽  
Nikolay Korchevin
Keyword(s):  
Carbon Atom ◽  
Chlorine Atom ◽  
Sulfur Atom ◽  
Density Functional ◽  
Theoretical Study ◽  
Thiol Group ◽  
Nucleophilic Attack ◽  
Substitution Product ◽  
Reaction Proceeds ◽  
Theoretical Mechanism

The theoretical mechanism of the interaction of 1,3-dichloropropene with 1,2-ethanedithiol in the system "hydrazine hydrate-KOH" has been proposed by the method of B3LYP / 6-311 ++ G (d, p) in the framework of the theory of the electron-density functional according to which the reaction proceeds successively in several stages, including the nucleophilic substitution of the chlorine atom present in the sp3-hybridized carbon atom with a sulfur atom to form a mono-substitution product that undergoes a prototropic allylic rearrangement that migrates the double bond to the sulfur atom, followed by closure in the dithiolane cycle due to the nucleophilic attack of the sulfide anion of the second thiol group of the reagent per carbon atom located in the γ-position with respect to the second chlorine atom.

scholarly journals QUANTUM-CHEMICAL STUDY OF THE REACTION MECHANISM 1,2-ETHANEDIIOL WITH 1,3-DICHLOROPROPENE

2020 ◽  
Vol 2018 (1) ◽  
pp. 56-57
Author(s):  
Elena Chirkina ◽  
Leonid Krivdin ◽  
Nikolay Korchevin
Keyword(s):  
Carbon Atom ◽  
Sulfur Atom ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Thiol Group ◽  
Chemical Study ◽  
Nucleophilic Attack ◽  
Substitution Product ◽  
Reaction Proceeds ◽  
Theoretical Mechanism

The theoretical mechanism of the interaction of 1,3-dichloropropene with 1,2- ethanedithiol in the system "hydrazine hydrate-KOH" has been proposed by the method of B3LYP / 6- 311 ++ G (d, p) in the framework of the theory of the electron-density functional according to which the reaction proceeds successively in several stages, including the nucleophilic substitution of the chlorine atom present in the sp3-hybridized carbon atom with a sulfur atom to form a mono-substitution product that undergoes a prototropic allylic rearrangement that migrates the double bond to the sulfur atom, followed by closure in the dithiolane cycle due to the nucleophilic attack of the sulfide anion of the second thiol group of the reagent per carbon atom located in the γ-position with respect to the second chlorine atom.

scholarly journals THEORETICAL STUDY OF THE INTERACTION OF 1,2-Ethanedithiol With 1,3-Dichloropropene in the Hydrazrazine Hydrate System

2018 ◽  
Vol 1 (12) ◽  
pp. 114-120
Author(s):  
Elena Chirkina
Keyword(s):  
Carbon Atom ◽  
Chlorine Atom ◽  
Density Functional ◽  
Thiol Group ◽  
Nucleophilic Attack ◽  
Substitution Product ◽  
Chemical Studies ◽  
Allyl Rearrangement ◽  
Quantum Chemical Studies ◽  
Theoretical Mechanism

According to the results of quantum chemical studies in the framework of the electron density functional theory, the B3LYP / 6-311 ++ G (d, p) method proposed a theoretical mechanism for the interaction of 1,3-dichloropropene with 1,2-ethanedithiol in the hydrazine-hydrateKOH system. It was shown that the reaction proceeds sequentially in several stages, including the nucleophilic substitution of the chlorine atom of the sp3 hybridized carbon atom to the sulfur atom with the formation of the mono-substitution product, which undergoes prototropic allyl rearrangement, providing the double bond to the atom sulfur. Next, the dithiolan ring closes due to the nucleophilic attack of the sulfide anion of the second thiol group of the reagent on the carbon atom, which is in the γ position relative to the second chlorine atom. The resulting vinyldithiolan is isomerized to a more stable ethylidene-dithiolan as a result of prototropic allyl rearrangement

scholarly journals Understanding the reaction mechanism of the regioselective piperidinolysis of aryl 1-(2,4-dinitronaphthyl) ethers in DMSO: Kinetic and DFT studies

2021 ◽  
Vol 46 ◽  
pp. 146867832110274
Author(s):  
Yasmen M Moghazy ◽  
Nagwa MM Hamada ◽  
Magda F Fathalla ◽  
Yasser R Elmarassi ◽  
Ezzat A Hamed ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Density Functional ◽  
Function Analysis ◽  
Density Functional Theory Method ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Nucleophilic Attack ◽  
Common Mechanism ◽  
Slow Step ◽  
Rate Determining Step

Reactions of aryl 1-(2,4-dinitronaphthyl) ethers with piperidine in dimethyl sulfoxide at 25oC resulted in substitution of the aryloxy group at the ipso carbon atom. The reaction was measured spectrophotochemically and the kinetic studies suggested that the titled reaction is accurately third order. The mechanism is began by fast nucleophilic attack of piperidine on C1 to form zwitterion intermediate (I) followed by deprotonation of zwitterion intermediate (I) to the Meisenheimer ion (II) in a slow step, that is, SB catalysis. The regular variation of activation parameters suggested that the reaction proceeded through a common mechanism. The Hammett equation using reaction constant σo values and Brønsted coefficient value showed that the reaction is poorly dependent on aryloxy substituent and the reaction was significantly associative and Meisenheimer intermediate-like. The mechanism of piperidinolysis has been theoretically investigated using density functional theory method using B3LYP/6-311G(d,p) computational level. The combination between experimental and computational studies predicts what mechanism is followed either through uncatalyzed or catalyzed reaction pathways, that is, SB and SB-GA. The global parameters of the reactants, the proposed activated complexes, and the local Fukui function analysis explained that C1 carbon atom is the most electrophilic center of ether. Also, kinetics and theoretical calculation of activation energies indicated that the mechanism of the piperidinolysis passed through a two-step mechanism and the proton transfer process was the rate determining step.

scholarly journals Neutral Rhenadicarbaboranes with Re(CO)2(NO) Vertices: A Theoretical Study of Building Blocks for Rhenacarborane-Based Drug Delivery Agents

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 110 ◽  
Author(s):  
Amr A. A. Attia ◽  
Alexandru Lupan ◽  
Radu Silaghi-Dumitrescu ◽  
R. Bruce King
Keyword(s):  
Drug Delivery ◽  
Density Functional Theory ◽  
Carbon Atom ◽  
Related Species ◽  
Density Functional ◽  
Theoretical Study ◽  
Building Blocks ◽  
Rhenium Atom ◽  
Functional Theory

The rhenadicarbaborane carbonyl nitrosyls (C2Bn−3Hn−1)Re(CO)2(NO), (n = 8 to 12), of interest in drug delivery agents based on the experimentally known C2B9H11Re(CO)2(NO) and related species, have been investigated by density functional theory. The lowest energy structures of these rhenadicarbaboranes are all found to have central ReC2Bn−3 most spherical closo deltahedra in accord with their 2n + 2 Wadean skeletal electrons. Carbon atoms are found to be located preferentially at degree 4 vertices in such structures. Furthermore, rhenium atoms are preferentially located at a highest degree vertex, typically a vertex of degree 5. Only for the 9-vertex C2B6H8Re(CO)2(NO) system are alternative isocloso deltahedral isomers found within ~8 kcal/mol of the lowest energy closo isomer. Such 9-vertex isocloso structures provide a degree 6 vertex for the rhenium atom flanked by degree 4 vertices for each carbon atom.

scholarly journals Theoretical Study on Epoxide Ring-opening in CO2/Epoxide Copolymerization Catalyzed by Bifunctional Salen-Type Cobalt(III) Complexes: Influence of Stereoelectronic Factors

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 328
Author(s):  
Karol Dyduch ◽  
Aleksandra Roznowska ◽  
Monika Srebro-Hooper ◽  
Bun Yeoul Lee ◽  
Artur Michalak
Keyword(s):  
Carbon Atom ◽  
Ring Opening ◽  
Density Functional ◽  
Model Systems ◽  
Conformational Space ◽  
Nucleophilic Attack ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
The Real ◽  
Ring Opening Reaction

Propylene oxide (PO) binding and ring-opening reaction with the bifunctional CO2/epoxide copolymerization catalyst, based on the Co(III)-salcy complex including two quaternary ammonium salts with n-butyl substituents (N+-chains) were investigated by Density Functional Theory (DFT) calculations and compared with the model systems without the N+-chains. The importance of the different possible stereoisomers and the stereoselectivity of these processes for (S)- and (R)-enantiomers of PO were considered. To explore the conformational space for the real catalyst, a complex approach, developed previously was applied. The calculations for the model systems directly demonstrate that PO-ring opening proceeds preferentially in trans catalysts’ configuration and no participation of cis-β isomers is viable; nucleophilic attack at the methylene-carbon atom is preferred over that at methine-carbon atom. For the real bifunctional catalyst, with the (S,S)-configuration of cyclohexane, the results indicate a preference of (R)-PO ring-opening over (S)-PO ring-opening (ca. 6:5). Concerning stereoisomers resulting from the orientation of N+-chains in the real catalyst, different groups of structures participate in the ring-opening reaction for (R)-PO, and different for (S)-PO. The high population of nonreactive complexes of (R)-PO may be the key factor responsible for decreasing the activity of the analyzed catalyst in the epoxide ring-opening reaction.

Réactivité de la combinaison anthracène–lithium vis-à-vis des nitriles

1975 ◽  
Vol 53 (21) ◽  
pp. 3158-3166 ◽  
Author(s):  
Jean-Paul Mazaleyrat
Keyword(s):  
Electron Transfer ◽  
Carbon Atom ◽  
Transfer Process ◽  
Nucleophilic Addition ◽  
Nucleophilic Attack ◽  
Electron Transfer Process ◽  
Ethereal Solution ◽  
Competitive Reactions ◽  
Reaction Proceeds

Lithium anthracenylide in ethereal solution behaves as a basic reagent towards nitriles with acidic hydrogens. However, in the case of nitriles with a tertiary α-carbon atom, two competitive reactions may occur: nucleophilic attack and electron transfer. The nucleophilic addition is faster, but because of its reversibility, the reaction proceeds, through the electron transfer process which is followed by the irreversible breaking of the C—CN bond, towards the formation of 9-alkyl-9,10-dihydroanthracene.

Density Functional Theoretical Study on the Mechanism of Alcoholysis of Acylpalladium(II) Complexes

2017 ◽  
Vol 42 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Hamed Chegini ◽  
Ali Morsali ◽  
Mohammad Reza Bozorgmehr ◽  
S. Ali Beyramabadi
Keyword(s):  
Carbon Monoxide ◽  
Carbon Atom ◽  
Solvent Effects ◽  
Energy Barrier ◽  
Density Functional ◽  
Theoretical Study ◽  
Experimental Studies ◽  
Reductive Elimination ◽  
Rate Determining Step ◽  
Insertion Mechanism

The mechanism of alcoholysis of acylpalladium(II) complexes relevant to the alternating copolymerisation of ethene and carbon monoxide has been investigated theoretically in detail. The solvolysis of acylpalladium(II) complexes is an important step in palladium-catalysed reactions. Based on experimental studies, two mechanisms have been proposed for this process, which consist of a concerted reductive elimination and an insertion mechanism (reductive elimination via a Meisenheimer intermediate). Both mechanisms include deprotonating of an acylpalladium(II) complex and according to our calculations, any mechanism involving this step, has an energy barrier higher than that of the rate-determining step. We propose a new mechanism for the insertion in which proton transfer to Pd is simultaneous with an inner-sphere attack of the alkoxide ligand (OCH3) at the carbon atom of the palladium-bound carbonyl group (new Meisenheimer intermediate). Considering solvent effects, the activation energies of the two mechanisms and other contingent mechanisms were calculated and compared with each other and the experimental results.

scholarly journals Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4466
Author(s):  
Duichun Li ◽  
Bin Xing ◽  
Baojun Wang ◽  
Ruifeng Li
Keyword(s):  
Acid Site ◽  
Density Functional ◽  
Theoretical Study ◽  
Atomic Radius ◽  
Acid Sites ◽  
Isomorphous Substitution ◽  
Dispersion Correction ◽  
Brønsted Acidity ◽  
Functional Theory ◽  
Brönsted Acidity

Systematic periodic density functional theory computations including dispersion correction (DFT-D) were carried out to determine the preferred location site of Zr atoms in sodalite (SOD) and CHA-type topology frameworks, including alumino-phosphate-34 (AlPO-34) and silico-alumino-phosphate-34 (SAPO-34), and to determine the relative stability and Brönsted acidity of Zr-substituted forms of SOD, AlPO-34, and SAPO-34. Mono and multiple Zr atom substitutions were considered. The Zr substitution causes obvious structural distortion because of the larger atomic radius of Zr than that of Si, however, Zr-substituted forms of zeolites are found to be more stable than pristine zeolites. Our results demonstrate that in the most stable configurations, the preferred favorable substitutions of Zr in substituted SOD have Zr located at the neighboring sites of the Al-substituted site. However, in the AlPO-34 and SAPO-34 frameworks, the Zr atoms are more easily distributed in a dispersed form, rather than being centralized. Brönsted acidity of substituted zeolites strongly depends on Zr content. For SOD, substitution of Zr atoms reduces Brönsted acidity. However, for Zr-substituted forms of AlPO-34 and SAPO-34, Brönsted acidity of the Zr-O(H)-Al acid sites are, at first, reduced and, then, the presence of Zr atoms substantially increased Brönsted acidity of the Zr-O(H)-Al acid site. The results in the SAPO-34-Zr indicate that more Zr atoms substantially increase Brönsted acidity of the Si-O(H)-Al acid site. It is suggested that substituted heteroatoms play an important role in regulating and controlling structural stability and Brönsted acidity of zeolites.

Cyclisierung von Di(tert-butyl-methyl)ketazin zu 1,2-Diaza-3-bora- und 1,2-Diaza-3-sila-cyclopent-5-enen / Cyclization of Di(tert-butyl-methyl)ketazine to 1,2-Diaza-3-bora- and 1,2-Diaza-3-sila-cyclopent-5-enes

2006 ◽  
Vol 61 (10) ◽  
pp. 1261-1274 ◽  
Author(s):  
Florian Armbruster ◽  
Nina Armbruster ◽  
Uwe Klingebiel ◽  
Mathias Noltemeyer ◽  
Stefan Schmatz
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Chlorine Atom ◽  
Quantum Chemical ◽  
Membered Ring ◽  
Substitution Product ◽  
Tert Butyl ◽  
Isomeric Structures

The results of quantum chemical calculations on lithium ketazides suggest mainly four isomeric structures with different modes of lithium coordination (A-D). A monolithium ketazide thf-adduct (1) was isolated supporting the results of the quantum chemical calculations. In reactions of the lithiated di(tert-butyl-methyl)ketazine with BCl3 and Cl2BPh, 1,2-aza-azonia-3-borata-cyclopent-5-enes (2, 3) were isolated. Substitution of a chlorine atom of 2 and 3 with t-BuLi leads to the formation of derivatives 4 and 5. HCl elimination from 2 with Et3N gives - via a diazaboracyclopentene (6) - a bicyclus 7. In the reaction of the dilithiated ketazine with F2BN(SiMe3)2, the diaza-boracyclopentene 8 is obtained while with Cl4Si, F3SiN(SiMe3)2, and Cl2SiMe2 the diazasilacyclopentenes 9 - 11 are generated. SiF4 reacts with the dilithium ketazide to give a spirocyclus (12). The monolithium ketazide and Cl2SiMe2 react at 30 °C to give a four-membered ring isomer of the substitution product which is formed via a 1,3-chlorine shift from silicon to carbon (13). A tetrameric silanolate was isolated as a by-product in this reaction. It gives evidence for the structure of lithium ketazide A. Crystal structures of 5, 7, 10, and 14 are reported.

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