Computational study of the mechanism of thermal decomposition of xanthates in the gas phase (the Chugaev reaction)

Vélez, Ederley; Quíjano, Jairo; Notario, Rafael; Murillo, Juliana; Ramírez, José Ernesto

doi:10.1002/poc.1383

Cited by 19 publications

(13 citation statements)

References 31 publications

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“…Recently, V elez group did an extensive investigation on the pyrolysis of carbonate esters, carbamates and dithiocarbonates at higher level methods. [34][35][36][37][38][39] All these calculations supported the second pathways. Di®erent theoretical levels and di®erent basis sets were compared by Deleuze group 40 in the pyrolysis of EtSC(¼S)OMe and its substituent e®ects with the conclusion that MP2 method gave comparable activation energies as CCSD(T).…”

Section: Introductionsupporting

confidence: 58%

Theoretical studies on the pyrolysis of (Thion)carbonates

2014

J. Theor. Comput. Chem.

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MP2/6-31G(d) was employed to investigate the theoretical calculations on the pyrolysis of alkyl methyl (thion)carbonates, where alkyl groups referred to ethyl, isopropyl and t-butyl groups. Nine possible pathways were considered for the pyrolysis of alkyl methyl thioncarbonates, while only seven possible pathways were found to pyrolyze alkyl methyl carbonates. Both of them had three pathways to generate the desired alkene products. Not only thermal elimination pathways were calculated, other possible mechanisms, such as rearrangements and nucleophilic substitutions, were also considered. The progress of the reactions was also investigated by the calculation of Wiberg bond indices at MP2/6-31G(d) level.

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Section: Introductionsupporting

confidence: 58%

Theoretical studies on the pyrolysis of (Thion)carbonates

2014

J. Theor. Comput. Chem.

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“…The binding energy (BE) positions of the Cd 3d, Zn 2p and S 2p core level photoelectrons are attributed to CdS and ZnS as expected [44,45]. The XP spectra showed a single chemical species for Cd Figure 1 Suggested breakdown of metal ethyl xanthato precursor at 250°C by a modified Chugaev elimination mechanism [42]. with Cd 3d 5/2 at 405.2 eV with a spin-orbit splitting of 6.8 eV as expected for the ?…”

Section: Resultsmentioning

confidence: 69%

“…This technique is suitable for semiconductor fabrication and uses easily prepared precursors. The xanthato precursors are expected to decompose by a modified Chugaev elimination mechanism [42]. The Chugaev elimination mechanism (Fig.…”

Section: Resultsmentioning

confidence: 99%

The deposition of thin films of cadmium zinc sulfide Cd1−x Zn x S at 250 °C from spin-coated xanthato complexes: a potential route to window layers for photovoltaic cells

2017

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Thin films of Cd 1-x Zn x S (CZS) were prepared by a novel spin coating/melt method from cadmium ethylxanthato [Cd(C 2 H 5 OCS 2 ) 2 ] and zinc ethylxanthato [Zn(C 2 H 5 OCS 2 ) 2 ] in x ratios of 0-0.15 and of 1. A solution of the precursor(s) in THF was spin coated onto a glass substrate and then heated at 250°C for 1 h under N 2 . The thickness of the film formed can be controlled by varying the solution composition and/or the spin rate of the coating. A total metal precursor solution concentration of 50 mM was used in all cases. The films were characterized by p-XRD, SEM, EDX, ICP-AES, XPS, UV-Vis absorption spectroscopy, Raman spectroscopy and resistivity measurements. The band gaps of the films were between 2.35-2.58 and 3.75 eV (0 B x B 0.15 and at x = 1). The resistivity of Cd 1-x Zn x S films was found to vary linearly with zinc contents, and the properties of the films suggest potential application to photovoltaics as window layers. This work is the first study to demonstrate Cd 1-x Zn x S thin films by a spin coating/melt method from xanthato precursors.

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“…The progress of this reaction has been followed through these parameters like in other theoretical studies on mechanisms carried out by us [18][19][20][21][22][23][24], and the values are shown in Table III.…”

Section: Resultsmentioning

confidence: 99%

“…We have selected the classical transition state theory [16,17] to calculate the kinetic parameters. The equations used have been reported by us in previous works [18][19][20][21][22][23][24].…”

Section: Computational Detailsmentioning

confidence: 99%

Gas-Phase Elimination Reaction of Ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate: A Computational Study

Vélez

Ruíz

Quíjano

et al. 2015

Int. J. Chem. Kinet.

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The gas‐phase elimination reaction of ethyl (5‐cyanomethyl‐1,3,4‐thiadiazol‐2‐yl)carbamate has been studied computationally at the MP2/6–31++G(2d,p) level of theory. The values of the activation parameters and rate constants for the thermal decomposition were evaluated over a temperature range from 405.0 to 458.0 K. The temperature dependence of the rate constants was used to deduce the modified Arrhenius expression: log k405–458 K = (9.01 ± 0.49) + (1.32 ± 0.16) log T – (6946 ± 30) 1/T, which is in good agreement with the expression obtained from experimental data. The results confirm that the mechanism is a cis‐concerted elimination that occurs in two steps: The first one corresponds to the formation of ethylene and an intermediate, 5‐(cyanomethyl)‐1,3,4‐thiadiazol‐2‐yl‐carbamic acid, via a six‐membered cyclic transition state, and the second one is the decarboxylation of this intermediate via a four‐membered cyclic transition step, leading to carbon dioxide and the corresponding 1,3,4‐thiadiazole derivative (5‐amino‐1,3,4‐thiadiazole‐2‐acetonitrile). The connectivity of transition states with their respective minima was verified through intrinsic reaction coordinate calculations, and the progress of the reaction was followed by means of Wiberg bond indices, resulting that both transition states have an “early” character, nearer to the reactants than to the products.

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Computational study of the mechanism of thermal decomposition of xanthates in the gas phase (the Chugaev reaction)

Cited by 19 publications

References 31 publications

Theoretical studies on the pyrolysis of (Thion)carbonates

Theoretical studies on the pyrolysis of (Thion)carbonates

The deposition of thin films of cadmium zinc sulfide Cd1−x Zn x S at 250 °C from spin-coated xanthato complexes: a potential route to window layers for photovoltaic cells

Gas-Phase Elimination Reaction of Ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate: A Computational Study

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