Synthesis and characterization of para-pyridine linked NHC palladium complexes and their studies for the Heck–Mizoroki coupling reaction

Abstract

This paper describes the synthesis of 1-(pyridine-4-ylmethyl) NHC and their Pd(II) and Ag(I) complexes, which are fully characterized. Interestingly, we have also synthesized a Pd complex 3a-CO₃3 using a more direct treatment of K₂CO₃ with PdCl₂. 3a-CO₃3 represents the first reported solid structure of a Pd η²-carbonato complex stabilized by an NHC framework. 3a-CO₃3 can be easily converted to a PdCl₂ derivative by treating it with chloroform. We have found these palladium complexes mediate the Heck–Mizoroki coupling with a low catalyst loading. Furthermore, we also expand such catalytic manifold toward constructing fused polyaromatic substrates, a highly useful class of compounds in optoelectronic chemistry.