dc.contributor.advisor | | |
dc.creator | Gallardo Villagrán, Manuel | es |
dc.creator | Vidal Barrero, Fernando | es |
dc.creator | Palma Ramírez, María del Pilar | es |
dc.creator | Álvarez González, Eleuterio | es |
dc.creator | Chen, Eugene Y. X. | es |
dc.creator | Cámpora Pérez, Juan | es |
dc.date.accessioned | 2022-10-06T11:04:15Z | |
dc.date.available | 2022-10-06T11:04:15Z | |
dc.date.issued | 2019 | |
dc.identifier.citation | Gallardo Villagrán, M., Vidal Barrero, F., Palma Ramírez, M.d.P., Álvarez González, E., Chen, E.Y.X. y Cámpora Pérez, J. (2019). Aluminium(iii) dialkyl 2,6-bisimino-4R-dihydropyridinates(−1): selective synthesis, structure and controlled dimerization. Dalton Transactions, 48, 9104. https://doi.org/10.1039/c9dt00847k. | |
dc.identifier.issn | 1477-9226 | es |
dc.identifier.issn | 1477-9234 | es |
dc.identifier.uri | https://hdl.handle.net/11441/137686 | |
dc.description.abstract | A family of stable and otherwise selectively unachievable 2,6-bisimino-4-R-1,4-dihydropyridinate
aluminium (III) dialkyl complexes [AlR’2(4-R-i
PrBIPH)] (R = Bn, Allyl; R’ = Me, Et, i
Bu) have been
synthesized, taking advantage of a method for the preparation of the corresponding 4-R-1,4-dihydropiridine precursors developed in our group. All the dihydropyrdinate(−1) dialkyl aluminium complexes
have been fully characterized by 1
H- 13C-NMR, elemental analysis and in the case 2’a, also by X-ray
diffraction studies. Upon heating in toluene solution at 110 °C, the dimethyl derivatives 2a and 2’a
dimerize selectively through a double cycloaddition. This reaction leads to the formation of two new C–C
bonds that involve the both meta positions of the two 4-R-1,4-dihydropyridinate fragments, resulting the
binuclear aluminium species [Me2Al(4-R-i
PrHBIP)]2 (R = Bn (3a); allyl (3’a)). Experimental kinetics showed
that the dimerization of 2’a obeys second order rate with negative activation entropy, which is consistent
with a bimolecular rate-determining step. Controlled methanolysis of both 3a and 3’a release the metalfree dimeric bases, (4-Bn-i
PrHBIPH)2 and (4-allyl-i
PrHBIPH)2, providing a convenient route to these
potentially useful ditopic ligands. When the R’ groups are bulkier than Me (2b, 2’b and 2’c), the dimerization is hindered or fully disabled, favoring the formation of paramagnetic NMR-silent species, which have
been identified on the basis of a controlled methanolysis of the final organometallic products. Thus, when
a toluene solution of [AlEt2(4-Bn-i
PrBIPH)] (2b) was heated at 110 °C, followed by the addition of methanol in excess, it yields a mixture of the dimer (4-Bn-i
PrHBIPH)2 and the aromatized base 4-Bn-i
PrBIP, in
ca. 1 : 2 ratio, indicating that the dimerization of 2b competes with its spontaneous dehydrogenation,
yielding a paramagnetic complex containing a AlEt2 unit and a non-innocent (4-Bn-i
PrBIP)•− radicalanion ligand. Similar NMR monitoring experiments on the thermal behavior of [AlEt2(4-allyl-i
PrBIPH)] (2’b)
and [Ali
Bu2(4-allyl-iPrBIPH)] (2’c) showed that these complexes do not dimerize, but afford exclusively
NMR silent products. When such thermally treated samples were subjected to methanolysis, they resulted
in mixtures of the alkylated 4-allyl-i
PrBIP and non-alkylated i
PrBIP ligand, suggesting that dehydrogenation and deallylation reactions take place competitively | es |
dc.description.sponsorship | Ministerio de Economía y Competitividad de España (MINECO) y los Fondos europeos FEDER-CTQ2015-68978-P y PRX14/00339 | es |
dc.description.sponsorship | United States National Science Foundation-CHE-1664915 | es |
dc.format | application/pdf | es |
dc.format.extent | 13 p. | es |
dc.language.iso | eng | es |
dc.publisher | Royal Society of Chemistry | es |
dc.relation.ispartof | Dalton Transactions, 48, 9104. | |
dc.rights | Attribution-NonCommercial-NoDerivatives 4.0 Internacional | * |
dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | * |
dc.title | Aluminium(iii) dialkyl 2,6-bisimino-4R-dihydropyridinates(−1): selective synthesis, structure and controlled dimerization | es |
dc.type | info:eu-repo/semantics/article | es |
dcterms.identifier | https://ror.org/03yxnpp24 | |
dc.type.version | info:eu-repo/semantics/acceptedVersion | es |
dc.rights.accessRights | info:eu-repo/semantics/openAccess | es |
dc.contributor.affiliation | Universidad de Sevilla. Departamento de Química Inorgánica | es |
dc.contributor.affiliation | Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental | |
dc.relation.projectID | CTQ2015-68978-P | es |
dc.relation.projectID | PRX14/00339 | es |
dc.relation.projectID | CHE-1664915 | es |
dc.relation.publisherversion | https://dx.doi.org/10.1039/c9dt00847k | es |
dc.identifier.doi | 10.1039/c9dt00847k | es |
dc.journaltitle | Dalton Transactions | es |
dc.publication.volumen | 48 | es |
dc.publication.initialPage | 9104 | es |
dc.contributor.funder | Ministerio de Economía y Competitividad (MINECO). España | es |
dc.contributor.funder | European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER) | es |
dc.contributor.funder | United States National Science Foundation | es |