Trace amount CuII (ppm) and mixture design of CuII/PdII catalyzed Suzuki cross-coupling reactions based on the cooperative interaction of metal with a conjugated pyridylspirobifluorene

Self-assembly of Cu/psf sheets and layer-by-layer (LbL) growth of PEI-(Cu/psf)n films were carried out and characterized (psf = 2,2′,7,7′-tetra(4-pyridyl)-9,9′-spirobifluorene). A mixture design was performed to evaluate the singular and combined catalytic effects of Cu(II), Pd(II) and psf ligands in the Suzuki cross-coupling reactions. The results showed that copper exhibited high catalytic activities in the presence of psf ligands. The (CuII/psf)n films were used as the reservoirs of catalysts capable of gradually discharging highly active catalytic moieties to promote the coupling reactions with ultra low Cu-loadings (as low as 1.4 × 10−5 mol%).