Synthesis of a new class of unsymmetrical PCP′ pincer ligands and their palladium (II) complexes: X-ray structure determination of PdCl{C6H3-2-CH2PPh2-6-CH2PBut2}

The unsymmetrical PCP′ pincer ligands {C6H4-1-CH2PPh2-3-CH2PBut2} and {C6H4-1-CH2PPh2-3-CH2PPri2} and the corresponding palladium complexes: PdCl{C6H3-2-CH2PPh2-6-CH2PBut2} and PdCl{C6H3-2-CH2PPh2-6-CH2PPri2} have been synthesized in good yields. The molecular structure of PdCl{C6H3-2-CH2PPh2-6-CH2PBut2} was determined through a single crystal X-ray diffraction study. The palladium center was found to be located into a slightly distorted square planar environment in which the {C6H4-1-CH2PPh2-3-CH2PBut2} ligand is coordinated as a tridentate, PCP pincer type chelate. The complex, PdCl{C6H3-2-CH2PPh2-6-CH2PPri2} catalyzes the Heck coupling of iodobenzene with styrene.