Palladium Complexes with Triazolyldiylidene. Structural Features and Catalytic Applications

Abstract

Our recently described 1,2,4-trimethyltriazolyldiylidene ligand (ditz) has been coordinated to two different palladium sources, namely, Pd(OAc)2 and Pd(acac)2, affording two different complexes that have been fully characterized. Remarkably, the product from the reaction with Pd(acac)2 shows activation of the C−H bonds of two terminal methyl groups of the acac ligands of Pd(acac)2, affording a 12-membered metallacycle with three palladium centers. The reaction product from the reaction with Pd(AcO)2 was shown to be an efficient catalyst in C−C coupling reactions, such as the Heck reaction and the acylation of aryl halides with aldehydes.

Hydrodefluorination of carbon–fluorine bonds by the synergistic action of a ruthenium–palladium catalyst

“…1) [33][34][35][36][37][38][39] . The preparation of such types of heterodimetallic complexes allowed us to study several catalytic processes in which each metal fragment facilitated a mechanistically different cycle 33,35,36,40 .…”

Quaternary 4-Amino-1,2,4-triazolium Salts: Crystal Structures of Ionic Liquids and N-Heterocyclic Carbene (NHC) Complexes

“…Often imidazolium salts are used, but recently more and more triazolederived carbenes have been reported. Thus, syntheses and structures of 1,2,4-triazol-5-ylidene transition metal complexes [21,22], even di-NHC complexes derived from the 1,2,4-trimethyl-1,2,4-triazolium dica-tion [23], have been published. Only a few examples of heteroatom N-substituted triazole-based carbenes are known, such as N-alkyloxy-1,2,4-triazol-5-ylidene [24] and N-dialkylamino-1,2,4-triazol-5-ylidene [25] systems.…”

Metal compounds with rigid polyaromatic ligands. Catalytic consequences

“…In this particular case, the addition of base results in a decrease of the TEP value from 2047.5 to 2029.5 cm -1 . This strategy has been extensively studied by Glorius, 96 César and Lavigne. 97,98 Scheme 1.4…”

“…A pesar de este gran potencial, solo se han descritos pocos ejemplos hasta ahora, 44,96,[133][134][135] algunos de los cuales incluyen procesos intermoleculares. 44,96,132,135 Basados en estos precedentes, decidimos explorar la actividad catalítica de los complejos 3J y 4J. Las reacciones las llevamos a cabo con halogenuro de arilo (bromobenceno o yodobenceno), hidrocinamaldehido, pirrolidona y 2% mol del respectivo catalizador en DMF a 120ºC, durante 16h (Esquema 7.24).…”

“…Bajo estas condiciones de reacción ambos catalizadores mostraron rendimiento entre moderados a bajos, si comparamos con otros ejemplos descritos en la literatura. 44,96,132,135 El complejo que incorpora el ligando 3-cloropiridina 4J fue ligeramente más activo que el derivado de acetonitrilo 3J. Los rendimientos más elevados se obtuvieron utilizando yodobenceno como sustrato.…”