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Rhodium and Iridium Mediated C-H and O-H Bond Activation of Two Schiff Base Ligands: Synthesis, Characterization and Catalytic Properties of the Organometallic Complexes

Reaction of [Rh(PPh(3))(3)Cl] with two Schiff base ligands, viz. N-(2′-hydroxyphenyl)furan-2-aldimine (H (2) L (1)) and N-(2′-hydroxyphenyl)thiophene-2-aldimine (H (2) L (2)), in refluxing toluene affords organorhodium complexes of type [Rh(PPh(3))(2)(L)Cl] (L = L(1) and L(2)). Similar reaction with...

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Detalles Bibliográficos
Autores principales: Sengupta, Poulami, Das, Rituparna, Dhibar, Papu, Paul, Piyali, Bhattacharya, Samaresh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8380818/
https://www.ncbi.nlm.nih.gov/pubmed/34434917
http://dx.doi.org/10.3389/fchem.2021.696460
Descripción
Sumario:Reaction of [Rh(PPh(3))(3)Cl] with two Schiff base ligands, viz. N-(2′-hydroxyphenyl)furan-2-aldimine (H (2) L (1)) and N-(2′-hydroxyphenyl)thiophene-2-aldimine (H (2) L (2)), in refluxing toluene affords organorhodium complexes of type [Rh(PPh(3))(2)(L)Cl] (L = L(1) and L(2)). Similar reaction with [Ir(PPh(3))(3)Cl] yields organoiridium complexes of type [Ir(PPh(3))(2)(L) (H)] (L = L(1) and L(2)). Crystal structures of [Rh(PPh(3))(2)(L(1))Cl] and [Ir(PPh(3))(2)(L(2)) (H)] have been determined, where the imine ligands are found to bind to the metal centers as CNO-donors. Structures of [Rh(PPh(3))(2)(L(2))Cl] and [Ir(PPh(3))(2)(L(1)) (H)] have been optimized by density functional theory method. Formation of the organometallic complexes is believed to proceed via C-H and O-H bond activation of the imine ligands. All four complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows an oxidation on the positive side of SCE and a reduction on the negative side. The organoiridium complexes are found to efficiently catalyze Suzuki-type C-C cross coupling reactions.