Effect of the nuclearity on the catalytic performance of a series of Pd(II) complexes in the Suzuki-Miyaura reaction
Gracjan Kurpik, Anna Walczak, Mirosław Gilski, Jack M. Harrowfield, Artur R. Stefankiewicz
Abstract
Development of well-defined multivalent systems with densely packed multiple functional groups located within a single molecular structure provides an excellent opportunity to generate catalysts of enhanced activity. A series of mono-, di- and trinuclear Pd(II) complexes based on polyketonate ligands allied with 2,2′-bipyridine has been designed, synthesized and fully characterized in both solution and solid state. The mono-, di- and tritopic β-diketonate molecules serve as scaffolds for Pd(II) active sites which, in the two latter cases, are forced into close proximity. Application of the complexes as catalysts in Suzuki-Miyaura cross-coupling as a model reaction has revealed significant differences in reaction yields and a trend in reactivity reflecting their nuclearity.