Electronic aspects of the hydride transfer mechanism. Ab initio analytical gradient studies of the cyclopropenyl‐cation/lithium hydride model reactant system
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Electronic aspects of the hydride transfer mechanism. Ab initio analytical gradient studies of the cyclopropenyl‐cation/lithium hydride model reactant system

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Electronic aspects of the hydride transfer mechanism. Ab initio analytical gradient studies of the cyclopropenyl‐cation/lithium hydride model reactant system

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dc.contributor.author Tapia, O.
dc.contributor.author Andres, J.
dc.contributor.author Aulló Reverte, Josep Maria
dc.contributor.author Bränden, C.I.
dc.date.accessioned 2010-06-14T09:30:38Z
dc.date.available 2010-06-14T09:30:38Z
dc.date.issued 1985
dc.identifier.uri http://hdl.handle.net/10550/12963
dc.language.iso en en
dc.relation http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JCPSA6000083000009004673000001&idtype=cvips&prog=normal&doi= en
dc.source Tapia, O.; Andrès, J.; Aulló, J.M.; Bränden, C.I. Electronic aspects of the hydride transfer mechanism. Ab initio analytical gradient studies of the cyclopropenyl‐cation/lithium hydride model reactant system. En: Journal of Chemical Physics, 1985, vol. 83, no. 9 en
dc.subject Ab Initio Calculations ; Chemical Reactions ; Cycloalkenes ; Cations ; Lithium Hydrides ; Redox Process ; Biological Materials en
dc.title Electronic aspects of the hydride transfer mechanism. Ab initio analytical gradient studies of the cyclopropenyl‐cation/lithium hydride model reactant system en
dc.type info:eu-repo/semantics/article en
dc.type info:eu-repo/semantics/publishedVersion en
dc.subject.unesco UNESCO::FÍSICA en
dc.subject.unesco UNESCO::FÍSICA::Química física en
dc.identifier.doi 10.1063/1.449039 en
dc.description.abstractenglish The electronic mechanisms of a model hydride transfer reaction are theoretically studied with ab inito RHF and UHF SCF MO procedures at the 4‐31G basis set level and analytical gradient methods. The model system describes the reduction of cyclopropenyl cation to cyclopropene by the oxidation of lithium hydride to lithium cation. The molecular fragments corresponding to the asymptotic reactive channels characterizing the stepwise mechanisms currently discussed in the literature have been characterized. The binding energy between the fragments is estimated within a simple electrostatic approximate scheme. The results show that a hydride‐ion mechanism is a likely pathway for this particular system. The system is thereafter thoroughly studied from the supermolecule approach. Reaction paths for the ground and first triplet electronic states have been calculated. The hypersurface is explored from a geometrical disposition of the reactants that mimics the one found in several dehydrogenases (perpendicular configuration). A hydride ion is found to be the particle transferred on the unconstrained as well as the constrained reaction pathways in the ground electronic state. In the triplet state (perpendicular configuration) the mechanism is stepwise: electron transfer followed by a hydrogen atom transfer. It has been noticed that the perpendicular geometrical disposition of the reactants plays an important role by polarizing the susceptible cyclopropene C–H bond in the sense of increasing the electronic density at the hydrogen nucleus. This provides a clue to rationalize several dehydrogenase’s active site structure and mechanism. The reactant molecular complex found in the inverted potential energy curves, namely the LiH‐‐‐Cp+ association has an electronic distribution which can be described as a hydride ion cementing two electron deficient centers corresponding to the cyclopropenyl and the lithium cations. Direct CI calculations confirm the overall picture obtained above. en
dc.description.private Josep.M.Aullo@uv.es en

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