Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution
Autor(a) principal: | |
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Data de Publicação: | 2007 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Journal of the Brazilian Chemical Society (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000400005 |
Resumo: | The neutral hydrolysis of formamide in aqueous solution involving up to four explicit solvent molecules was theoretically investigated using high level ab initio methods and including the bulk solvent effect through the Polarizable Continuum Model (PCM). We have analyzed cyclic transition states structures involving bifunctional catalysis and a general base catalysis structure. Both a stepwise mechanism with tetrahedral intermediate formation and a concerted mechanism were investigated. Our calculations at CCSD(T)/6-311+G(2df,2p)//MP2/6-31G(d) level predict an observable activation free energy barrier of 48.7 kcal mol-1, corresponding to a stepwise water catalyzed mechanism with two water molecules into the transition state. Liquid phase geometry optimization was also performed, but the effect on the activation free energy is modest. Tests with density functional theory were carried out. The B3LYP/6-31G(d) calculation underestimates the barrier by 13 kcal mol-1, whereas the B3LYP/6-311+G(2df,2p) method predicts an accurate barrier. The present study raises important questions about the reliability of the experimental activation free energy of 31.0 kcal mol-1 and suggests that the neutral hydrolysis of formamide does not take place at all. |
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Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solutionamide hydrolysisab initioreaction mechanismbifunctional catalysisThe neutral hydrolysis of formamide in aqueous solution involving up to four explicit solvent molecules was theoretically investigated using high level ab initio methods and including the bulk solvent effect through the Polarizable Continuum Model (PCM). We have analyzed cyclic transition states structures involving bifunctional catalysis and a general base catalysis structure. Both a stepwise mechanism with tetrahedral intermediate formation and a concerted mechanism were investigated. Our calculations at CCSD(T)/6-311+G(2df,2p)//MP2/6-31G(d) level predict an observable activation free energy barrier of 48.7 kcal mol-1, corresponding to a stepwise water catalyzed mechanism with two water molecules into the transition state. Liquid phase geometry optimization was also performed, but the effect on the activation free energy is modest. Tests with density functional theory were carried out. The B3LYP/6-31G(d) calculation underestimates the barrier by 13 kcal mol-1, whereas the B3LYP/6-311+G(2df,2p) method predicts an accurate barrier. The present study raises important questions about the reliability of the experimental activation free energy of 31.0 kcal mol-1 and suggests that the neutral hydrolysis of formamide does not take place at all.Sociedade Brasileira de Química2007-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000400005Journal of the Brazilian Chemical Society v.18 n.4 2007reponame:Journal of the Brazilian Chemical Society (Online)instname:Sociedade Brasileira de Química (SBQ)instacron:SBQ10.1590/S0103-50532007000400005info:eu-repo/semantics/openAccessAlmerindo,Gizelle I.Pliego Jr.,Josefredo R.eng2007-09-18T00:00:00Zoai:scielo:S0103-50532007000400005Revistahttp://jbcs.sbq.org.brONGhttps://old.scielo.br/oai/scielo-oai.php||office@jbcs.sbq.org.br1678-47900103-5053opendoar:2007-09-18T00:00Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)false |
dc.title.none.fl_str_mv |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
title |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
spellingShingle |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution Almerindo,Gizelle I. amide hydrolysis ab initio reaction mechanism bifunctional catalysis |
title_short |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
title_full |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
title_fullStr |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
title_full_unstemmed |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
title_sort |
Ab initio investigation of the kinetics and mechanism of the neutral hydrolysis of formamide in aqueous solution |
author |
Almerindo,Gizelle I. |
author_facet |
Almerindo,Gizelle I. Pliego Jr.,Josefredo R. |
author_role |
author |
author2 |
Pliego Jr.,Josefredo R. |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Almerindo,Gizelle I. Pliego Jr.,Josefredo R. |
dc.subject.por.fl_str_mv |
amide hydrolysis ab initio reaction mechanism bifunctional catalysis |
topic |
amide hydrolysis ab initio reaction mechanism bifunctional catalysis |
description |
The neutral hydrolysis of formamide in aqueous solution involving up to four explicit solvent molecules was theoretically investigated using high level ab initio methods and including the bulk solvent effect through the Polarizable Continuum Model (PCM). We have analyzed cyclic transition states structures involving bifunctional catalysis and a general base catalysis structure. Both a stepwise mechanism with tetrahedral intermediate formation and a concerted mechanism were investigated. Our calculations at CCSD(T)/6-311+G(2df,2p)//MP2/6-31G(d) level predict an observable activation free energy barrier of 48.7 kcal mol-1, corresponding to a stepwise water catalyzed mechanism with two water molecules into the transition state. Liquid phase geometry optimization was also performed, but the effect on the activation free energy is modest. Tests with density functional theory were carried out. The B3LYP/6-31G(d) calculation underestimates the barrier by 13 kcal mol-1, whereas the B3LYP/6-311+G(2df,2p) method predicts an accurate barrier. The present study raises important questions about the reliability of the experimental activation free energy of 31.0 kcal mol-1 and suggests that the neutral hydrolysis of formamide does not take place at all. |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000400005 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000400005 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0103-50532007000400005 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
dc.source.none.fl_str_mv |
Journal of the Brazilian Chemical Society v.18 n.4 2007 reponame:Journal of the Brazilian Chemical Society (Online) instname:Sociedade Brasileira de Química (SBQ) instacron:SBQ |
instname_str |
Sociedade Brasileira de Química (SBQ) |
instacron_str |
SBQ |
institution |
SBQ |
reponame_str |
Journal of the Brazilian Chemical Society (Online) |
collection |
Journal of the Brazilian Chemical Society (Online) |
repository.name.fl_str_mv |
Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ) |
repository.mail.fl_str_mv |
||office@jbcs.sbq.org.br |
_version_ |
1750318168129142784 |