Synthesis, Characterization, and Catalytic Studies of Dinuclear d⁸ Metal-Phosphazane Complexes

Herein we report the synthesis and characterization of two diphosphazane (P-N-P) ligands, along with their corresponding novel palladium and platinum complexes. Compounds were characterized by FTIR and NMR spectroscopy, single crystal X-ray diffraction (SC-XRD), and powder X-ray diffraction (PXRD)), as well as mass spectrometry. The Pd(II) complex of the p-phenyldiphosphazane was shown to effectively and efficiently catalyze Suzuki-Miyaura cross-coupling reactions between a variety of substrates. Yields were as high as 96%, with reaction times as short as 15 min at room temperature and open to air. No additional supporting ligands, such as triphenylphosphine, were needed. The work reported here expands the use of phosphazane ligands to support catalytic centers and provides an understanding of phosphazane metal-ligand bonding interactions (specifically diphosphazanes).