Palladium(II) Pincer Type Complexes Containing ONO Donor Heterocyclic Hydrazones: Synthesis, Structure and Catalytic Activity Towards the Suzuki–Miyaura Cross-Coupling of 3-Bromochromone and Arylboronic Acids via C–Br Activation

Three new pincer type palladium(II) complexes 1–3 synthesized by reacting palladium precursor [PdCl 2 (PPh 3 ) 2 ] with ONO heterocyclic hydrazone ligands H 2 L1-3 in equimolar quantities were well characterized using single-crystal XRD, analytical and spectroscopic data. These complexes were examined as homogeneous catalysts for the Suzuki–Miyaura cross-coupling of 3-bromochromone with a range of arylboronic acids in ethanol medium. Catalytic transformations progressed smoothly under aerobic conditions with 0.01 mol% of catalyst load at room temperature to afford an array of 3-arylated chromones (6a–o). This catalyst was reused up to five cycles and favourably this protocol does not require any external oxidant, additives and phase transfer reagents. Graphical Abstract