Dimethylphosphinate bridged binuclear Rh(i) catalysts for the alkoxycarbonylation of aromatic C-H bonds

Iturmendi, Amaia (Universidad de Zaragoza) ; Sanz Miguel, Pablo J. (Universidad de Zaragoza) ; Popoola, Saheed A. ; Al-Saadi, Abdulaziz A. ; Iglesias, Manuel (Universidad de Zaragoza) ; Oro, Luis A. (Universidad de Zaragoza)

Resumen: A variety of binuclear rhodium(I) complexes featuring two bridging dimethylphosphinate ligands ((CH3)2PO2-) have been prepared and tested in the alkoxycarbonylation of aromatic C–H bonds. The complex [Rh(µ-¿O,O'-(CH3)2PO2)(cod)]2 has been prepared by a reaction of [Rh(µ-MeO)(cod)]2 with 2 equivalents of dimethylphosphinic acid. Binuclear complexes [Rh(µ-¿O,O'-(CH3)2PO2)(CO)L]2 (L = PPh3, P(OMe)Ph2 and P(OPh)3) were obtained by carbonylation of the related mononuclear complexes [Rh(¿O-(CH3)2PO2)(cod)(L)], which were prepared in situ by the reaction of [Rh(µ-¿O,O'-(CH3)2PO2)(cod)]2 with 2 equivalents of L. Conversely, if L = IPr, the reaction of [Rh(µ-¿O,O'-(CH3)2PO2)(CO)L]2 with carbon monoxide affords the mononuclear complex [Rh(¿O-(CH3)2PO2)(CO)2IPr]. The subsequent reaction with trimethylamine N-oxide gives the corresponding binuclear complex [Rh(µ-¿O,O'-(CH3)2PO2)(CO)(IPr)]2 by abstraction of one of the carbonyl ligands. Complexes [Rh(µ-¿O,O'-(CH3)2PO2)(cod)]2 and [Rh(¿O-(CH3)2PO2)(cod)(L)] (L = IPr, PPh3, P(OMe)Ph2, P(OPh)3) are active precatalysts in the alkoxycarbonylation of C–H bonds, with the ligand system playing a key role in the catalytic activity. The complexes that feature more labile Rh–L bonds give rise to better catalysts, probably due to the more straightforward substitution of L by a second carbonyl ligand, since a more electrophilic carbonyl carbon atom is more susceptible toward aryl migration. In fact, complexes [Rh(µ-¿O,O'-(CH3)2PO2)(CO)2]2 and [Rh(µ-Cl)(CO)2]2, generated in situ from [Rh(µ-¿O,O'-(CH3)2PO2)(cod)]2 and [Rh(µ-Cl)(cod)2]2, respectively, are the most active catalysts tested in this work.

Idioma: Inglés

DOI: 10.1039/c6dt03010f

Año: 2016

Publicado en: Dalton Transactions 45, 42 (2016), 16955-16965
ISSN: 1477-9226

Factor impacto JCR: 4.029 (2016)

Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 7 / 46 = 0.152 (2016) - Q1 - T1

Factor impacto SCIMAGO: 1.229 - Inorganic Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E07
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CSD2009-0050

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)
Área (Departamento): Proy. investigación HWA (Dpto. Química Inorgánica)