Hydration of Aliphatic Nitriles Catalyzed by an Osmium Polyhydride: Evidence for an Alternative Mechanism

Babón, J.C. (Universidad de Zaragoza) ; Esteruelas, M.A. ; López, A.M. (Universidad de Zaragoza) ; Oñate, E.

Resumen: The hexahydride OsH6(PiPr3)2 competently catalyzes the hydration of aliphatic nitriles to amides. The main metal species under the catalytic conditions are the trihydride osmium(IV) amidate derivatives OsH3{¿2-N, O-[HNC(O)R]}(PiPr3)2, which have been isolated and fully characterized for R = iPr and tBu. The rate of hydration is proportional to the concentrations of the catalyst precursor, nitrile, and water. When these experimental findings and density functional theory calculations are combined, the mechanism of catalysis has been established. Complexes OsH3{¿2-N, O-[HNC(O)R]}(PiPr3)2 dissociate the carbonyl group of the chelate to afford ¿1-N-amidate derivatives, which coordinate the nitrile. The subsequent attack of an external water molecule to both the C(sp) atom of the nitrile and the N atom of the amidate affords the amide and regenerates the ¿1-N-amidate catalysts. The attack is concerted and takes place through a cyclic six-membered transition state, which involves Cnitrile···O-H···Namidate interactions. Before the attack, the free carbonyl group of the ¿1-N-amidate ligand fixes the water molecule in the vicinity of the C(sp) atom of the nitrile. © 2021 American Chemical Society.

Idioma: Inglés

DOI: 10.1021/acs.inorgchem.1c00380

Año: 2021

Publicado en: Inorganic Chemistry 60, 10 (2021), 7284-7296
ISSN: 0020-1669

Factor impacto JCR: 5.436 (2021)

Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 5 / 46 = 0.109 (2021) - Q1 - T1

Factor impacto SCIMAGO: 1.121 - Inorganic Chemistry (Q1) - Chemistry (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E06-20R
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/RED2018-102387-T
Financiación: info:eu-repo/grantAgreement/ES/MINECO/CTQ2017-82935-P

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)