Novel Amphiphilic Lantern-type Cu(II)-Pd(II) Complex Coordinated with Four 2-Pyridone Derivatives Having A Long Alkyl Chain

ABSTRACT

Novel amphiphilic dinuclear complex, copper(II) tetrakis(6-hydroxy-nicotinic dodesyl amide)palladium(II) complex with long hydrophobic alkyl chains ([CuPd(hnda)₄(DMF)] (1)), was synthesized and characterized by electronic absorption, IR, and ESR spectroscopic and elemental and X-ray diffraction methods. X-ray analysis of the single crystal of 1 obtained from a DMF/H₂O mixed solution revealed a lantern-type dinuclear Pd(II)-Cu(II) structure bridged by four HNDA ligands, in which Pd(II) and Cu(II) ions were respectively tetrakis-coordinated with the nitrogen and oxygen atoms of four HNDA ligands in the equatorial plane. The apical site of Cu(II) atom was occupied by a DMF molecule, and the apical site of Pd(II) atom was weakly linked with a water molecule. The four HNDA dodesyl groups extended outward to form a hydrophobic layer, while the lantern-type dinuclear cores formed a hydrophilic layer. They constructed alternate layered structures composed of hydrophobic and hydrophilic groups. DMF solution of 1 gave an intense ESR spectrum (g_⊥ = 2.08, g_// = 2.41, |A_//| = 9.89 mT) characteristic of a distorted square planar structure, to which the addition of water broadened it. These behaviors were discussed in connection with the structures of amphiphilic complex 1.