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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The relativistic effects on the methane activation by gold(I) cations

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Author(s):
Santiago, Regis T. [1] ; Vichietti, Rafael M. [2] ; Machado, Francisco B. C. [2] ; Haiduke, Roberto L. A. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Dept Quim & Fis Mol, CP 780, BR-13560970 Sao Carlos, SP - Brazil
[2] Inst Tecnol Aeronaut, Dept Quim, BR-12228900 Sao Jose Dos Campos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Journal of Chemical Physics; v. 154, n. 24 JUN 28 2021.
Web of Science Citations: 0
Abstract

The reactivity of gold has been investigated for a long time. Here, we performed an in-depth analysis of relativistic effects over the chemical kinetic properties of elementary reactions associated with methane activation by gold(I) cations, CH4 + Au+ <-> AuCH2+ + H-2. The global reaction is modeled as a two-step process, CH4 + Au+ <-> HAuCH3+ <-> AuCH2+ + H-2. Moreover, the barrierless dissociation of the initial adduct between reactants, AuCH4+, is discussed as well. Higher-order relativistic treatments are used to provide corrections beyond the commonly considered scalar effects of relativistic effective core potentials (RECPs). Although the scalar relativistic contributions predominate, lowering the forward barrier heights by 48.4 and 36.1 kcal mol(-1), the spin-orbit coupling effect can still provide additional reductions of these forward barrier heights by as much as 9% (1.0 and 2.2 kcal mol(-1)). The global reaction proceeds rapidly at low temperatures to the intermediate attained after the first hydrogen transfer, HAuCH3+. The relativistic corrections beyond the ones from RECPs are still able to double the rate constant of the CH4 + Au+ -> HAuCH3+ process at 300 K, while the reverse reaction becomes five times slower. The formation of global products from this intermediate only becomes significant at much higher temperatures (similar to 1500 K upward). The scalar relativistic contributions decrease the dissociation energy of the initial adduct, AuCH4+, into the global products by 105.8 kcal mol(-1), while the spin-orbit effect provides an extra lowering of 1.8 kcal mol(-1). Published under an exclusive license by AIP Publishing. (AU)

FAPESP's process: 14/23714-1 - Electronic structure relativistic calculations for evaluation of new prolapse-free basis sets
Grantee:Roberto Luiz Andrade Haiduke
Support Opportunities: Regular Research Grants
FAPESP's process: 18/05691-5 - Application of quantum chemistry methods in the study of possible routes for formation of small molecular systems in different astrophysical environments
Grantee:Rafael Mario Vichietti
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 13/07375-0 - CeMEAI - Center for Mathematical Sciences Applied to Industry
Grantee:Francisco Louzada Neto
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 19/25105-6 - Polycyclic aromatic hydrocarbons (PAH's): doping, vacancy, reactivity, excited states: a multiconfigurational approach
Grantee:Francisco Bolivar Correto Machado
Support Opportunities: Regular Research Grants