Synthesis, structures and catalytic properties of palladacycles derived from N,N-dimethylaminomethylferrocene

Abstract

Palladacycles 2 – 4 containing the N , N -dimethylaminomethylferrocenyl backbone and three pyridine co-ligands have been prepared and structurally characterized. Their catalytic activities in promoting the methanolysis of the pesticide parathion were investigated. Cyclopalladated complexes with a N , N -dimethylaminomethylferrocenyl (dmaf) backbone and three pyridine co-ligands, [Pd{(η 5 -C 5 H 5 )Fe[(η 5 -C 5 H 3 )CH 2 NMe 2 ]}Cl(R-Py)] ( 2 : R = 4-H; 3 : R = 4-cyano; 4 : 4- N , N -dimethylamino) have been synthesized and characterized. The single crystal X-ray diffraction analyses show that the palladium(II) in both 3 or 4 is coordinated in a distorted square planar geometry with the two nitrogen atoms trans to each other. The three palladacyles were shown to greatly catalyze the methanolysis of the P S containing pesticide parathion but showed different accelerations. It was found that the replacement of phenyl by ferrocenyl in the palladacycle backbone of 2 lowers the kinetic pKa s s of the Pd-(HOCH 3 ) required for activity by almost 2 units.