Trace amount Pd(ppm)-catalyzed Sonogashira, Heck and Suzuki cross-coupling reactions based on synergistic interaction with an asymmetric conjugated pyridinespirofluorene

A multilayer film of (Pd2+/1)(10) was simply fabricated by Pd(II) and 2-Br-2',7,7'-tri(4-pyridyl)-9,9'-spirobifluorene (1, Br-tpsf) through a layer-by-layer self-assembly method. The film loaded on a quartz slide as a catalyst reservoir could gradually release high active catalytic species to promote Sonogashira, Heck and Suzuki cross-coupling reactions, with extremely low Pd-loading of 11.0 x 10(-6) mol% and high catalytic efficiency in EtOH-H2O system.