Dimeric palladium 1,2,3-triazol-5-ylidene complexes – synthesis, structure, reactivity and catalytic properties in Suzuki coupling†
Jan Lorkowski,Patrycja Żak,Maciej Kubicki,Cezary Pietraszuk,Dawid Jędrzkiewicz,Jolanta Ejfler
New Journal of Chemistry Pub Date : 05/11/2018 00:00:00 , DOI:10.1039/C8NJ00981C
Abstract

New dimeric palladium 1,2,3-triazol-5-ylidene complexes of the general formula [{Pd(μ-Cl)Cl(tzNHC)}2] (tzNHC = 1-mesityl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene; 1-hexyl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene and 1-butyl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene) were synthesized and characterized by spectroscopic methods, X-ray analysis and DFT calculations. For the mesityl substituted complex, the crystallographic structures of both the cisoidal and transoidal isomer were obtained. In the presence of an excess of 4-tolylboronic acid, the loss of the tzNHC ligand from the palladium coordination sphere as a 5-tolyltriazolium salt was observed. The complexes are precursors of palladium species catalytically active in the coupling of arylboronic acids with aryl bromides.

Graphical abstract: Dimeric palladium 1,2,3-triazol-5-ylidene complexes – synthesis, structure, reactivity and catalytic properties in Suzuki coupling