Palladium Complexes with Triazolyldiylidene. Structural Features and Catalytic Applications

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.