Repercussion of a 1, 3-Hydrogen Shift in a Hydride-Osmium-Allenylidene Complex

Esteruelas, M.A. ; Oñate, E. ; Paz, S. (Universidad de Zaragoza) ; Vélez, A. (Universidad de Zaragoza)

Resumen: An unusual 1, 3-hydrogen shift from the metal center to the Cß atom of the C3-chain of the allenylidene ligand in a hydride-osmium(II)-allenylidene complex is the beginning of several interesting transformations in the cumulene. The hydride-osmium(II)-allenylidene complex was prepared in two steps, starting from the tetrahydride dimer [(Os(H···H){¿3-P, O, P-[xant(PiPr2)2]})2(µ-Cl)2][BF4]2 (1). Complex 1 reacts with 1, 1-diphenyl-2-propyn-1-ol to give the hydride-osmium(II)-alkenylcarbyne [OsHCl(CCH-CPh2){¿3-P, O, P-[xant(PiPr2)2]}]BF4 (2), which yields OsHCl(-C-C-CPh2){¿3-P, O, P-[xant(PiPr2)2]} (3) by selective abstraction of the Cß-H hydrogen atom of the alkenylcarbyne ligand with KtBuO. Complex 3 is metastable. According to results of DFT calculations, the migration of the hydride ligand to the Cß atom of the cumulene has an activation energy too high to occur in a concerted manner. However, the migration can be catalyzed by water, alcohols, and aldehydes. The resulting alkenylcarbyne-osmium(0) intermediate is unstable and evolves into a 7:3 mixture of the hydride-osmium(II)-indenylidene OsHCl(-CIndPh){¿3-P, O, P-[xant(PiPr2)2]} (4) and the osmanaphthalene OsCl(C9H6Ph){¿3-P, O, P-[xant(PiPr2)2]} (5). Protonation of 4 with HBF4 leads to the elongated dihydrogen complex [OsCl(¿2-H2)(-CIndPh){¿3-P, O, P-[xant(PiPr2)2]}]BF4 (6), while the protonation of 5 regenerates 2. In contrast to 4, complex 6 evolves to a half-sandwich indenyl derivative, [Os(¿5-IndPh)H{¿3-P, O, P-[xant(PiPr2)2]}][BF4]Cl (7). Phenylacetylene also provokes the 1, 3-hydrogen shift in 3. However, it does not participate in the migration. In contrast to water, alcohols, and aldehydes, it stabilizes the resulting alkenylcarbyne to afford [Os(CCH-CPh2)(¿2-HCCPh){¿3-P, O, P-[xant(PiPr2)2]}]Cl (8).

Idioma: Inglés

DOI: 10.1021/acs.organomet.1c00176

Año: 2021

Publicado en: Organometallics 40, 10 (2021), 1523-1537
ISSN: 0276-7333

Factor impacto JCR: 3.837 (2021)

Categ. JCR: CHEMISTRY, ORGANIC rank: 15 / 56 = 0.268 (2021) - Q2 - T1
Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 12 / 46 = 0.261 (2021) - Q2 - T1

Factor impacto SCIMAGO: 0.994 - Organic Chemistry (Q1) - Inorganic Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/FEDER E06-20R
Financiación: info:eu-repo/grantAgreement/ES/DGA/LMP148-18
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/CTQ2017-82935-P
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/RED2018-102387-T

Tipo y forma: Article (Published version)

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